diff --git a/init/uevent_listener.cpp b/init/uevent_listener.cpp
index 24b14c4..81486e1 100644
--- a/init/uevent_listener.cpp
+++ b/init/uevent_listener.cpp
@@ -23,7 +23,11 @@
 
 #include <memory>
 
+#include <android-base/chrono_utils.h>
+#include <android-base/file.h>
 #include <android-base/logging.h>
+#include <android-base/scopeguard.h>
+#include <android-base/stringprintf.h>
 #include <cutils/uevent.h>
 
 namespace android {
@@ -130,9 +134,19 @@
 
     int fd = openat(dfd, "uevent", O_WRONLY);
     if (fd >= 0) {
+        android::base::Timer t;
         write(fd, "add\n", 4);
+        const std::string fd_path = android::base::StringPrintf("/proc/self/fd/%d", fd);
+        std::string uevent_file_path;
+        android::base::Readlink(fd_path, &uevent_file_path);
         close(fd);
 
+        auto guard = android::base::make_scope_guard([&t, &uevent_file_path]() {
+            if (t.duration() > 50ms) {
+                LOG(WARNING) << "ReadUevent took " << t << " on '" << uevent_file_path << "'";
+            }
+        });
+
         Uevent uevent;
         while (ReadUevent(&uevent)) {
             if (callback(uevent) == ListenerAction::kStop) return ListenerAction::kStop;
diff --git a/libsparse/.clang-format b/libsparse/.clang-format
new file mode 120000
index 0000000..fd0645f
--- /dev/null
+++ b/libsparse/.clang-format
@@ -0,0 +1 @@
+../.clang-format-2
\ No newline at end of file
diff --git a/libsparse/Android.bp b/libsparse/Android.bp
index c7c089f..8ad339f 100644
--- a/libsparse/Android.bp
+++ b/libsparse/Android.bp
@@ -6,11 +6,11 @@
     recovery_available: true,
     unique_host_soname: true,
     srcs: [
-        "backed_block.c",
-        "output_file.c",
-        "sparse.c",
-        "sparse_crc32.c",
-        "sparse_err.c",
+        "backed_block.cpp",
+        "output_file.cpp",
+        "sparse.cpp",
+        "sparse_crc32.cpp",
+        "sparse_err.cpp",
         "sparse_read.cpp",
     ],
     cflags: ["-Werror"],
@@ -31,8 +31,8 @@
     name: "simg2img",
     host_supported: true,
     srcs: [
-        "simg2img.c",
-        "sparse_crc32.c",
+        "simg2img.cpp",
+        "sparse_crc32.cpp",
     ],
     static_libs: [
         "libsparse",
@@ -46,7 +46,7 @@
 cc_binary {
     name: "img2simg",
     host_supported: true,
-    srcs: ["img2simg.c"],
+    srcs: ["img2simg.cpp"],
     static_libs: [
         "libsparse",
         "libz",
@@ -58,7 +58,7 @@
 
 cc_binary_host {
     name: "append2simg",
-    srcs: ["append2simg.c"],
+    srcs: ["append2simg.cpp"],
     static_libs: [
         "libsparse",
         "libz",
diff --git a/libsparse/append2simg.c b/libsparse/append2simg.c
deleted file mode 100644
index eef8764..0000000
--- a/libsparse/append2simg.c
+++ /dev/null
@@ -1,140 +0,0 @@
-/*
- * Copyright (C) 2013 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#define _FILE_OFFSET_BITS 64
-#define _LARGEFILE64_SOURCE 1
-#define _GNU_SOURCE
-
-#include <errno.h>
-#include <fcntl.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <unistd.h>
-
-#include <sparse/sparse.h>
-#include "sparse_file.h"
-#include "backed_block.h"
-
-#ifndef O_BINARY
-#define O_BINARY 0
-#endif
-
-#if defined(__APPLE__) && defined(__MACH__)
-#define lseek64 lseek
-#endif
-#if defined(__APPLE__) && defined(__MACH__)
-#define lseek64 lseek
-#define off64_t off_t
-#endif
-
-void usage()
-{
-    fprintf(stderr, "Usage: append2simg <output> <input>\n");
-}
-
-int main(int argc, char *argv[])
-{
-    int output;
-    int output_block;
-    char *output_path;
-    struct sparse_file *sparse_output;
-
-    int input;
-    char *input_path;
-    off64_t input_len;
-
-    int tmp_fd;
-    char *tmp_path;
-
-    int ret;
-
-    if (argc == 3) {
-        output_path = argv[1];
-        input_path = argv[2];
-    } else {
-        usage();
-        exit(-1);
-    }
-
-    ret = asprintf(&tmp_path, "%s.append2simg", output_path);
-    if (ret < 0) {
-        fprintf(stderr, "Couldn't allocate filename\n");
-        exit(-1);
-    }
-
-    output = open(output_path, O_RDWR | O_BINARY);
-    if (output < 0) {
-        fprintf(stderr, "Couldn't open output file (%s)\n", strerror(errno));
-        exit(-1);
-    }
-
-    sparse_output = sparse_file_import_auto(output, false, true);
-    if (!sparse_output) {
-        fprintf(stderr, "Couldn't import output file\n");
-        exit(-1);
-    }
-
-    input = open(input_path, O_RDONLY | O_BINARY);
-    if (input < 0) {
-        fprintf(stderr, "Couldn't open input file (%s)\n", strerror(errno));
-        exit(-1);
-    }
-
-    input_len = lseek64(input, 0, SEEK_END);
-    if (input_len < 0) {
-        fprintf(stderr, "Couldn't get input file length (%s)\n", strerror(errno));
-        exit(-1);
-    } else if (input_len % sparse_output->block_size) {
-        fprintf(stderr, "Input file is not a multiple of the output file's block size");
-        exit(-1);
-    }
-    lseek64(input, 0, SEEK_SET);
-
-    output_block = sparse_output->len / sparse_output->block_size;
-    if (sparse_file_add_fd(sparse_output, input, 0, input_len, output_block) < 0) {
-        fprintf(stderr, "Couldn't add input file\n");
-        exit(-1);
-    }
-    sparse_output->len += input_len;
-
-    tmp_fd = open(tmp_path, O_WRONLY | O_CREAT | O_BINARY, 0664);
-    if (tmp_fd < 0) {
-        fprintf(stderr, "Couldn't open temporary file (%s)\n", strerror(errno));
-        exit(-1);
-    }
-
-    lseek64(output, 0, SEEK_SET);
-    if (sparse_file_write(sparse_output, tmp_fd, false, true, false) < 0) {
-        fprintf(stderr, "Failed to write sparse file\n");
-        exit(-1);
-    }
-
-    sparse_file_destroy(sparse_output);
-    close(tmp_fd);
-    close(output);
-    close(input);
-
-    ret = rename(tmp_path, output_path);
-    if (ret < 0) {
-        fprintf(stderr, "Failed to rename temporary file (%s)\n", strerror(errno));
-        exit(-1);
-    }
-
-    free(tmp_path);
-
-    exit(0);
-}
diff --git a/libsparse/append2simg.cpp b/libsparse/append2simg.cpp
new file mode 100644
index 0000000..99f4339
--- /dev/null
+++ b/libsparse/append2simg.cpp
@@ -0,0 +1,137 @@
+/*
+ * Copyright (C) 2013 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define _FILE_OFFSET_BITS 64
+#define _LARGEFILE64_SOURCE 1
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sparse/sparse.h>
+#include "backed_block.h"
+#include "sparse_file.h"
+
+#ifndef O_BINARY
+#define O_BINARY 0
+#endif
+
+#if defined(__APPLE__) && defined(__MACH__)
+#define lseek64 lseek
+#endif
+#if defined(__APPLE__) && defined(__MACH__)
+#define lseek64 lseek
+#define off64_t off_t
+#endif
+
+void usage() {
+  fprintf(stderr, "Usage: append2simg <output> <input>\n");
+}
+
+int main(int argc, char* argv[]) {
+  int output;
+  int output_block;
+  char* output_path;
+  struct sparse_file* sparse_output;
+
+  int input;
+  char* input_path;
+  off64_t input_len;
+
+  int tmp_fd;
+  char* tmp_path;
+
+  int ret;
+
+  if (argc == 3) {
+    output_path = argv[1];
+    input_path = argv[2];
+  } else {
+    usage();
+    exit(-1);
+  }
+
+  ret = asprintf(&tmp_path, "%s.append2simg", output_path);
+  if (ret < 0) {
+    fprintf(stderr, "Couldn't allocate filename\n");
+    exit(-1);
+  }
+
+  output = open(output_path, O_RDWR | O_BINARY);
+  if (output < 0) {
+    fprintf(stderr, "Couldn't open output file (%s)\n", strerror(errno));
+    exit(-1);
+  }
+
+  sparse_output = sparse_file_import_auto(output, false, true);
+  if (!sparse_output) {
+    fprintf(stderr, "Couldn't import output file\n");
+    exit(-1);
+  }
+
+  input = open(input_path, O_RDONLY | O_BINARY);
+  if (input < 0) {
+    fprintf(stderr, "Couldn't open input file (%s)\n", strerror(errno));
+    exit(-1);
+  }
+
+  input_len = lseek64(input, 0, SEEK_END);
+  if (input_len < 0) {
+    fprintf(stderr, "Couldn't get input file length (%s)\n", strerror(errno));
+    exit(-1);
+  } else if (input_len % sparse_output->block_size) {
+    fprintf(stderr, "Input file is not a multiple of the output file's block size");
+    exit(-1);
+  }
+  lseek64(input, 0, SEEK_SET);
+
+  output_block = sparse_output->len / sparse_output->block_size;
+  if (sparse_file_add_fd(sparse_output, input, 0, input_len, output_block) < 0) {
+    fprintf(stderr, "Couldn't add input file\n");
+    exit(-1);
+  }
+  sparse_output->len += input_len;
+
+  tmp_fd = open(tmp_path, O_WRONLY | O_CREAT | O_BINARY, 0664);
+  if (tmp_fd < 0) {
+    fprintf(stderr, "Couldn't open temporary file (%s)\n", strerror(errno));
+    exit(-1);
+  }
+
+  lseek64(output, 0, SEEK_SET);
+  if (sparse_file_write(sparse_output, tmp_fd, false, true, false) < 0) {
+    fprintf(stderr, "Failed to write sparse file\n");
+    exit(-1);
+  }
+
+  sparse_file_destroy(sparse_output);
+  close(tmp_fd);
+  close(output);
+  close(input);
+
+  ret = rename(tmp_path, output_path);
+  if (ret < 0) {
+    fprintf(stderr, "Failed to rename temporary file (%s)\n", strerror(errno));
+    exit(-1);
+  }
+
+  free(tmp_path);
+
+  exit(0);
+}
diff --git a/libsparse/backed_block.c b/libsparse/backed_block.c
deleted file mode 100644
index 794cd6b..0000000
--- a/libsparse/backed_block.c
+++ /dev/null
@@ -1,404 +0,0 @@
-/*
- * Copyright (C) 2010 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include <assert.h>
-#include <errno.h>
-#include <stdint.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include "backed_block.h"
-#include "sparse_defs.h"
-
-struct backed_block {
-	unsigned int block;
-	unsigned int len;
-	enum backed_block_type type;
-	union {
-		struct {
-			void *data;
-		} data;
-		struct {
-			char *filename;
-			int64_t offset;
-		} file;
-		struct {
-			int fd;
-			int64_t offset;
-		} fd;
-		struct {
-			uint32_t val;
-		} fill;
-	};
-	struct backed_block *next;
-};
-
-struct backed_block_list {
-	struct backed_block *data_blocks;
-	struct backed_block *last_used;
-	unsigned int block_size;
-};
-
-struct backed_block *backed_block_iter_new(struct backed_block_list *bbl)
-{
-	return bbl->data_blocks;
-}
-
-struct backed_block *backed_block_iter_next(struct backed_block *bb)
-{
-	return bb->next;
-}
-
-unsigned int backed_block_len(struct backed_block *bb)
-{
-	return bb->len;
-}
-
-unsigned int backed_block_block(struct backed_block *bb)
-{
-	return bb->block;
-}
-
-void *backed_block_data(struct backed_block *bb)
-{
-	assert(bb->type == BACKED_BLOCK_DATA);
-	return bb->data.data;
-}
-
-const char *backed_block_filename(struct backed_block *bb)
-{
-	assert(bb->type == BACKED_BLOCK_FILE);
-	return bb->file.filename;
-}
-
-int backed_block_fd(struct backed_block *bb)
-{
-	assert(bb->type == BACKED_BLOCK_FD);
-	return bb->fd.fd;
-}
-
-int64_t backed_block_file_offset(struct backed_block *bb)
-{
-	assert(bb->type == BACKED_BLOCK_FILE || bb->type == BACKED_BLOCK_FD);
-	if (bb->type == BACKED_BLOCK_FILE) {
-		return bb->file.offset;
-	} else { /* bb->type == BACKED_BLOCK_FD */
-		return bb->fd.offset;
-	}
-}
-
-uint32_t backed_block_fill_val(struct backed_block *bb)
-{
-	assert(bb->type == BACKED_BLOCK_FILL);
-	return bb->fill.val;
-}
-
-enum backed_block_type backed_block_type(struct backed_block *bb)
-{
-	return bb->type;
-}
-
-void backed_block_destroy(struct backed_block *bb)
-{
-	if (bb->type == BACKED_BLOCK_FILE) {
-		free(bb->file.filename);
-	}
-
-	free(bb);
-}
-
-struct backed_block_list *backed_block_list_new(unsigned int block_size)
-{
-	struct backed_block_list *b = calloc(sizeof(struct backed_block_list), 1);
-	b->block_size = block_size;
-	return b;
-}
-
-void backed_block_list_destroy(struct backed_block_list *bbl)
-{
-	if (bbl->data_blocks) {
-		struct backed_block *bb = bbl->data_blocks;
-		while (bb) {
-			struct backed_block *next = bb->next;
-			backed_block_destroy(bb);
-			bb = next;
-		}
-	}
-
-	free(bbl);
-}
-
-void backed_block_list_move(struct backed_block_list *from,
-		struct backed_block_list *to, struct backed_block *start,
-		struct backed_block *end)
-{
-	struct backed_block *bb;
-
-	if (start == NULL) {
-		start = from->data_blocks;
-	}
-
-	if (!end) {
-		for (end = start; end && end->next; end = end->next)
-			;
-	}
-
-	if (start == NULL || end == NULL) {
-		return;
-	}
-
-	from->last_used = NULL;
-	to->last_used = NULL;
-	if (from->data_blocks == start) {
-		from->data_blocks = end->next;
-	} else {
-		for (bb = from->data_blocks; bb; bb = bb->next) {
-			if (bb->next == start) {
-				bb->next = end->next;
-				break;
-			}
-		}
-	}
-
-	if (!to->data_blocks) {
-		to->data_blocks = start;
-		end->next = NULL;
-	} else {
-		for (bb = to->data_blocks; bb; bb = bb->next) {
-			if (!bb->next || bb->next->block > start->block) {
-				end->next = bb->next;
-				bb->next = start;
-				break;
-			}
-		}
-	}
-}
-
-/* may free b */
-static int merge_bb(struct backed_block_list *bbl,
-		struct backed_block *a, struct backed_block *b)
-{
-	unsigned int block_len;
-
-	/* Block doesn't exist (possible if one block is the last block) */
-	if (!a || !b) {
-		return -EINVAL;
-	}
-
-	assert(a->block < b->block);
-
-	/* Blocks are of different types */
-	if (a->type != b->type) {
-		return -EINVAL;
-	}
-
-	/* Blocks are not adjacent */
-	block_len = a->len / bbl->block_size; /* rounds down */
-	if (a->block + block_len != b->block) {
-		return -EINVAL;
-	}
-
-	switch (a->type) {
-	case BACKED_BLOCK_DATA:
-		/* Don't support merging data for now */
-		return -EINVAL;
-	case BACKED_BLOCK_FILL:
-		if (a->fill.val != b->fill.val) {
-			return -EINVAL;
-		}
-		break;
-	case BACKED_BLOCK_FILE:
-		/* Already make sure b->type is BACKED_BLOCK_FILE */
-		if (strcmp(a->file.filename, b->file.filename) ||
-				a->file.offset + a->len != b->file.offset) {
-			return -EINVAL;
-		}
-		break;
-	case BACKED_BLOCK_FD:
-		if (a->fd.fd != b->fd.fd ||
-				a->fd.offset + a->len != b->fd.offset) {
-			return -EINVAL;
-		}
-		break;
-	}
-
-	/* Blocks are compatible and adjacent, with a before b.  Merge b into a,
-	 * and free b */
-	a->len += b->len;
-	a->next = b->next;
-
-	backed_block_destroy(b);
-
-	return 0;
-}
-
-static int queue_bb(struct backed_block_list *bbl, struct backed_block *new_bb)
-{
-	struct backed_block *bb;
-
-	if (bbl->data_blocks == NULL) {
-		bbl->data_blocks = new_bb;
-		return 0;
-	}
-
-	if (bbl->data_blocks->block > new_bb->block) {
-		new_bb->next = bbl->data_blocks;
-		bbl->data_blocks = new_bb;
-		return 0;
-	}
-
-	/* Optimization: blocks are mostly queued in sequence, so save the
-	   pointer to the last bb that was added, and start searching from
-	   there if the next block number is higher */
-	if (bbl->last_used && new_bb->block > bbl->last_used->block)
-		bb = bbl->last_used;
-	else
-		bb = bbl->data_blocks;
-	bbl->last_used = new_bb;
-
-	for (; bb->next && bb->next->block < new_bb->block; bb = bb->next)
-		;
-
-	if (bb->next == NULL) {
-		bb->next = new_bb;
-	} else {
-		new_bb->next = bb->next;
-		bb->next = new_bb;
-	}
-
-	merge_bb(bbl, new_bb, new_bb->next);
-	if (!merge_bb(bbl, bb, new_bb)) {
-		/* new_bb destroyed, point to retained as last_used */
-		bbl->last_used = bb;
-	}
-
-	return 0;
-}
-
-/* Queues a fill block of memory to be written to the specified data blocks */
-int backed_block_add_fill(struct backed_block_list *bbl, unsigned int fill_val,
-		unsigned int len, unsigned int block)
-{
-	struct backed_block *bb = calloc(1, sizeof(struct backed_block));
-	if (bb == NULL) {
-		return -ENOMEM;
-	}
-
-	bb->block = block;
-	bb->len = len;
-	bb->type = BACKED_BLOCK_FILL;
-	bb->fill.val = fill_val;
-	bb->next = NULL;
-
-	return queue_bb(bbl, bb);
-}
-
-/* Queues a block of memory to be written to the specified data blocks */
-int backed_block_add_data(struct backed_block_list *bbl, void *data,
-		unsigned int len, unsigned int block)
-{
-	struct backed_block *bb = calloc(1, sizeof(struct backed_block));
-	if (bb == NULL) {
-		return -ENOMEM;
-	}
-
-	bb->block = block;
-	bb->len = len;
-	bb->type = BACKED_BLOCK_DATA;
-	bb->data.data = data;
-	bb->next = NULL;
-
-	return queue_bb(bbl, bb);
-}
-
-/* Queues a chunk of a file on disk to be written to the specified data blocks */
-int backed_block_add_file(struct backed_block_list *bbl, const char *filename,
-		int64_t offset, unsigned int len, unsigned int block)
-{
-	struct backed_block *bb = calloc(1, sizeof(struct backed_block));
-	if (bb == NULL) {
-		return -ENOMEM;
-	}
-
-	bb->block = block;
-	bb->len = len;
-	bb->type = BACKED_BLOCK_FILE;
-	bb->file.filename = strdup(filename);
-	bb->file.offset = offset;
-	bb->next = NULL;
-
-	return queue_bb(bbl, bb);
-}
-
-/* Queues a chunk of a fd to be written to the specified data blocks */
-int backed_block_add_fd(struct backed_block_list *bbl, int fd, int64_t offset,
-		unsigned int len, unsigned int block)
-{
-	struct backed_block *bb = calloc(1, sizeof(struct backed_block));
-	if (bb == NULL) {
-		return -ENOMEM;
-	}
-
-	bb->block = block;
-	bb->len = len;
-	bb->type = BACKED_BLOCK_FD;
-	bb->fd.fd = fd;
-	bb->fd.offset = offset;
-	bb->next = NULL;
-
-	return queue_bb(bbl, bb);
-}
-
-int backed_block_split(struct backed_block_list *bbl, struct backed_block *bb,
-		unsigned int max_len)
-{
-	struct backed_block *new_bb;
-
-	max_len = ALIGN_DOWN(max_len, bbl->block_size);
-
-	if (bb->len <= max_len) {
-		return 0;
-	}
-
-	new_bb = malloc(sizeof(struct backed_block));
-	if (new_bb == NULL) {
-		return -ENOMEM;
-	}
-
-	*new_bb = *bb;
-
-	new_bb->len = bb->len - max_len;
-	new_bb->block = bb->block + max_len / bbl->block_size;
-	new_bb->next = bb->next;
-	bb->next = new_bb;
-	bb->len = max_len;
-
-	switch (bb->type) {
-	case BACKED_BLOCK_DATA:
-		new_bb->data.data = (char *)bb->data.data + max_len;
-		break;
-	case BACKED_BLOCK_FILE:
-		new_bb->file.offset += max_len;
-		break;
-	case BACKED_BLOCK_FD:
-		new_bb->fd.offset += max_len;
-		break;
-	case BACKED_BLOCK_FILL:
-		break;
-	}
-
-	return 0;
-}
diff --git a/libsparse/backed_block.cpp b/libsparse/backed_block.cpp
new file mode 100644
index 0000000..7f5632e
--- /dev/null
+++ b/libsparse/backed_block.cpp
@@ -0,0 +1,380 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <assert.h>
+#include <errno.h>
+#include <stdint.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "backed_block.h"
+#include "sparse_defs.h"
+
+struct backed_block {
+  unsigned int block;
+  unsigned int len;
+  enum backed_block_type type;
+  union {
+    struct {
+      void* data;
+    } data;
+    struct {
+      char* filename;
+      int64_t offset;
+    } file;
+    struct {
+      int fd;
+      int64_t offset;
+    } fd;
+    struct {
+      uint32_t val;
+    } fill;
+  };
+  struct backed_block* next;
+};
+
+struct backed_block_list {
+  struct backed_block* data_blocks;
+  struct backed_block* last_used;
+  unsigned int block_size;
+};
+
+struct backed_block* backed_block_iter_new(struct backed_block_list* bbl) {
+  return bbl->data_blocks;
+}
+
+struct backed_block* backed_block_iter_next(struct backed_block* bb) {
+  return bb->next;
+}
+
+unsigned int backed_block_len(struct backed_block* bb) {
+  return bb->len;
+}
+
+unsigned int backed_block_block(struct backed_block* bb) {
+  return bb->block;
+}
+
+void* backed_block_data(struct backed_block* bb) {
+  assert(bb->type == BACKED_BLOCK_DATA);
+  return bb->data.data;
+}
+
+const char* backed_block_filename(struct backed_block* bb) {
+  assert(bb->type == BACKED_BLOCK_FILE);
+  return bb->file.filename;
+}
+
+int backed_block_fd(struct backed_block* bb) {
+  assert(bb->type == BACKED_BLOCK_FD);
+  return bb->fd.fd;
+}
+
+int64_t backed_block_file_offset(struct backed_block* bb) {
+  assert(bb->type == BACKED_BLOCK_FILE || bb->type == BACKED_BLOCK_FD);
+  if (bb->type == BACKED_BLOCK_FILE) {
+    return bb->file.offset;
+  } else { /* bb->type == BACKED_BLOCK_FD */
+    return bb->fd.offset;
+  }
+}
+
+uint32_t backed_block_fill_val(struct backed_block* bb) {
+  assert(bb->type == BACKED_BLOCK_FILL);
+  return bb->fill.val;
+}
+
+enum backed_block_type backed_block_type(struct backed_block* bb) {
+  return bb->type;
+}
+
+void backed_block_destroy(struct backed_block* bb) {
+  if (bb->type == BACKED_BLOCK_FILE) {
+    free(bb->file.filename);
+  }
+
+  free(bb);
+}
+
+struct backed_block_list* backed_block_list_new(unsigned int block_size) {
+  struct backed_block_list* b =
+      reinterpret_cast<backed_block_list*>(calloc(sizeof(struct backed_block_list), 1));
+  b->block_size = block_size;
+  return b;
+}
+
+void backed_block_list_destroy(struct backed_block_list* bbl) {
+  if (bbl->data_blocks) {
+    struct backed_block* bb = bbl->data_blocks;
+    while (bb) {
+      struct backed_block* next = bb->next;
+      backed_block_destroy(bb);
+      bb = next;
+    }
+  }
+
+  free(bbl);
+}
+
+void backed_block_list_move(struct backed_block_list* from, struct backed_block_list* to,
+                            struct backed_block* start, struct backed_block* end) {
+  struct backed_block* bb;
+
+  if (start == NULL) {
+    start = from->data_blocks;
+  }
+
+  if (!end) {
+    for (end = start; end && end->next; end = end->next)
+      ;
+  }
+
+  if (start == NULL || end == NULL) {
+    return;
+  }
+
+  from->last_used = NULL;
+  to->last_used = NULL;
+  if (from->data_blocks == start) {
+    from->data_blocks = end->next;
+  } else {
+    for (bb = from->data_blocks; bb; bb = bb->next) {
+      if (bb->next == start) {
+        bb->next = end->next;
+        break;
+      }
+    }
+  }
+
+  if (!to->data_blocks) {
+    to->data_blocks = start;
+    end->next = NULL;
+  } else {
+    for (bb = to->data_blocks; bb; bb = bb->next) {
+      if (!bb->next || bb->next->block > start->block) {
+        end->next = bb->next;
+        bb->next = start;
+        break;
+      }
+    }
+  }
+}
+
+/* may free b */
+static int merge_bb(struct backed_block_list* bbl, struct backed_block* a, struct backed_block* b) {
+  unsigned int block_len;
+
+  /* Block doesn't exist (possible if one block is the last block) */
+  if (!a || !b) {
+    return -EINVAL;
+  }
+
+  assert(a->block < b->block);
+
+  /* Blocks are of different types */
+  if (a->type != b->type) {
+    return -EINVAL;
+  }
+
+  /* Blocks are not adjacent */
+  block_len = a->len / bbl->block_size; /* rounds down */
+  if (a->block + block_len != b->block) {
+    return -EINVAL;
+  }
+
+  switch (a->type) {
+    case BACKED_BLOCK_DATA:
+      /* Don't support merging data for now */
+      return -EINVAL;
+    case BACKED_BLOCK_FILL:
+      if (a->fill.val != b->fill.val) {
+        return -EINVAL;
+      }
+      break;
+    case BACKED_BLOCK_FILE:
+      /* Already make sure b->type is BACKED_BLOCK_FILE */
+      if (strcmp(a->file.filename, b->file.filename) || a->file.offset + a->len != b->file.offset) {
+        return -EINVAL;
+      }
+      break;
+    case BACKED_BLOCK_FD:
+      if (a->fd.fd != b->fd.fd || a->fd.offset + a->len != b->fd.offset) {
+        return -EINVAL;
+      }
+      break;
+  }
+
+  /* Blocks are compatible and adjacent, with a before b.  Merge b into a,
+   * and free b */
+  a->len += b->len;
+  a->next = b->next;
+
+  backed_block_destroy(b);
+
+  return 0;
+}
+
+static int queue_bb(struct backed_block_list* bbl, struct backed_block* new_bb) {
+  struct backed_block* bb;
+
+  if (bbl->data_blocks == NULL) {
+    bbl->data_blocks = new_bb;
+    return 0;
+  }
+
+  if (bbl->data_blocks->block > new_bb->block) {
+    new_bb->next = bbl->data_blocks;
+    bbl->data_blocks = new_bb;
+    return 0;
+  }
+
+  /* Optimization: blocks are mostly queued in sequence, so save the
+     pointer to the last bb that was added, and start searching from
+     there if the next block number is higher */
+  if (bbl->last_used && new_bb->block > bbl->last_used->block)
+    bb = bbl->last_used;
+  else
+    bb = bbl->data_blocks;
+  bbl->last_used = new_bb;
+
+  for (; bb->next && bb->next->block < new_bb->block; bb = bb->next)
+    ;
+
+  if (bb->next == NULL) {
+    bb->next = new_bb;
+  } else {
+    new_bb->next = bb->next;
+    bb->next = new_bb;
+  }
+
+  merge_bb(bbl, new_bb, new_bb->next);
+  if (!merge_bb(bbl, bb, new_bb)) {
+    /* new_bb destroyed, point to retained as last_used */
+    bbl->last_used = bb;
+  }
+
+  return 0;
+}
+
+/* Queues a fill block of memory to be written to the specified data blocks */
+int backed_block_add_fill(struct backed_block_list* bbl, unsigned int fill_val, unsigned int len,
+                          unsigned int block) {
+  struct backed_block* bb = reinterpret_cast<backed_block*>(calloc(1, sizeof(struct backed_block)));
+  if (bb == NULL) {
+    return -ENOMEM;
+  }
+
+  bb->block = block;
+  bb->len = len;
+  bb->type = BACKED_BLOCK_FILL;
+  bb->fill.val = fill_val;
+  bb->next = NULL;
+
+  return queue_bb(bbl, bb);
+}
+
+/* Queues a block of memory to be written to the specified data blocks */
+int backed_block_add_data(struct backed_block_list* bbl, void* data, unsigned int len,
+                          unsigned int block) {
+  struct backed_block* bb = reinterpret_cast<backed_block*>(calloc(1, sizeof(struct backed_block)));
+  if (bb == NULL) {
+    return -ENOMEM;
+  }
+
+  bb->block = block;
+  bb->len = len;
+  bb->type = BACKED_BLOCK_DATA;
+  bb->data.data = data;
+  bb->next = NULL;
+
+  return queue_bb(bbl, bb);
+}
+
+/* Queues a chunk of a file on disk to be written to the specified data blocks */
+int backed_block_add_file(struct backed_block_list* bbl, const char* filename, int64_t offset,
+                          unsigned int len, unsigned int block) {
+  struct backed_block* bb = reinterpret_cast<backed_block*>(calloc(1, sizeof(struct backed_block)));
+  if (bb == NULL) {
+    return -ENOMEM;
+  }
+
+  bb->block = block;
+  bb->len = len;
+  bb->type = BACKED_BLOCK_FILE;
+  bb->file.filename = strdup(filename);
+  bb->file.offset = offset;
+  bb->next = NULL;
+
+  return queue_bb(bbl, bb);
+}
+
+/* Queues a chunk of a fd to be written to the specified data blocks */
+int backed_block_add_fd(struct backed_block_list* bbl, int fd, int64_t offset, unsigned int len,
+                        unsigned int block) {
+  struct backed_block* bb = reinterpret_cast<backed_block*>(calloc(1, sizeof(struct backed_block)));
+  if (bb == NULL) {
+    return -ENOMEM;
+  }
+
+  bb->block = block;
+  bb->len = len;
+  bb->type = BACKED_BLOCK_FD;
+  bb->fd.fd = fd;
+  bb->fd.offset = offset;
+  bb->next = NULL;
+
+  return queue_bb(bbl, bb);
+}
+
+int backed_block_split(struct backed_block_list* bbl, struct backed_block* bb,
+                       unsigned int max_len) {
+  struct backed_block* new_bb;
+
+  max_len = ALIGN_DOWN(max_len, bbl->block_size);
+
+  if (bb->len <= max_len) {
+    return 0;
+  }
+
+  new_bb = reinterpret_cast<backed_block*>(malloc(sizeof(struct backed_block)));
+  if (new_bb == NULL) {
+    return -ENOMEM;
+  }
+
+  *new_bb = *bb;
+
+  new_bb->len = bb->len - max_len;
+  new_bb->block = bb->block + max_len / bbl->block_size;
+  new_bb->next = bb->next;
+  bb->next = new_bb;
+  bb->len = max_len;
+
+  switch (bb->type) {
+    case BACKED_BLOCK_DATA:
+      new_bb->data.data = (char*)bb->data.data + max_len;
+      break;
+    case BACKED_BLOCK_FILE:
+      new_bb->file.offset += max_len;
+      break;
+    case BACKED_BLOCK_FD:
+      new_bb->fd.offset += max_len;
+      break;
+    case BACKED_BLOCK_FILL:
+      break;
+  }
+
+  return 0;
+}
diff --git a/libsparse/backed_block.h b/libsparse/backed_block.h
index 1a159be..3a75460 100644
--- a/libsparse/backed_block.h
+++ b/libsparse/backed_block.h
@@ -23,42 +23,40 @@
 struct backed_block;
 
 enum backed_block_type {
-	BACKED_BLOCK_DATA,
-	BACKED_BLOCK_FILE,
-	BACKED_BLOCK_FD,
-	BACKED_BLOCK_FILL,
+  BACKED_BLOCK_DATA,
+  BACKED_BLOCK_FILE,
+  BACKED_BLOCK_FD,
+  BACKED_BLOCK_FILL,
 };
 
-int backed_block_add_data(struct backed_block_list *bbl, void *data,
-		unsigned int len, unsigned int block);
-int backed_block_add_fill(struct backed_block_list *bbl, unsigned int fill_val,
-		unsigned int len, unsigned int block);
-int backed_block_add_file(struct backed_block_list *bbl, const char *filename,
-		int64_t offset, unsigned int len, unsigned int block);
-int backed_block_add_fd(struct backed_block_list *bbl, int fd,
-		int64_t offset, unsigned int len, unsigned int block);
+int backed_block_add_data(struct backed_block_list* bbl, void* data, unsigned int len,
+                          unsigned int block);
+int backed_block_add_fill(struct backed_block_list* bbl, unsigned int fill_val, unsigned int len,
+                          unsigned int block);
+int backed_block_add_file(struct backed_block_list* bbl, const char* filename, int64_t offset,
+                          unsigned int len, unsigned int block);
+int backed_block_add_fd(struct backed_block_list* bbl, int fd, int64_t offset, unsigned int len,
+                        unsigned int block);
 
-struct backed_block *backed_block_iter_new(struct backed_block_list *bbl);
-struct backed_block *backed_block_iter_next(struct backed_block *bb);
-unsigned int backed_block_len(struct backed_block *bb);
-unsigned int backed_block_block(struct backed_block *bb);
-void *backed_block_data(struct backed_block *bb);
-const char *backed_block_filename(struct backed_block *bb);
-int backed_block_fd(struct backed_block *bb);
-int64_t backed_block_file_offset(struct backed_block *bb);
-uint32_t backed_block_fill_val(struct backed_block *bb);
-enum backed_block_type backed_block_type(struct backed_block *bb);
-int backed_block_split(struct backed_block_list *bbl, struct backed_block *bb,
-		unsigned int max_len);
+struct backed_block* backed_block_iter_new(struct backed_block_list* bbl);
+struct backed_block* backed_block_iter_next(struct backed_block* bb);
+unsigned int backed_block_len(struct backed_block* bb);
+unsigned int backed_block_block(struct backed_block* bb);
+void* backed_block_data(struct backed_block* bb);
+const char* backed_block_filename(struct backed_block* bb);
+int backed_block_fd(struct backed_block* bb);
+int64_t backed_block_file_offset(struct backed_block* bb);
+uint32_t backed_block_fill_val(struct backed_block* bb);
+enum backed_block_type backed_block_type(struct backed_block* bb);
+int backed_block_split(struct backed_block_list* bbl, struct backed_block* bb, unsigned int max_len);
 
-struct backed_block *backed_block_iter_new(struct backed_block_list *bbl);
-struct backed_block *backed_block_iter_next(struct backed_block *bb);
+struct backed_block* backed_block_iter_new(struct backed_block_list* bbl);
+struct backed_block* backed_block_iter_next(struct backed_block* bb);
 
-struct backed_block_list *backed_block_list_new(unsigned int block_size);
-void backed_block_list_destroy(struct backed_block_list *bbl);
+struct backed_block_list* backed_block_list_new(unsigned int block_size);
+void backed_block_list_destroy(struct backed_block_list* bbl);
 
-void backed_block_list_move(struct backed_block_list *from,
-		struct backed_block_list *to, struct backed_block *start,
-		struct backed_block *end);
+void backed_block_list_move(struct backed_block_list* from, struct backed_block_list* to,
+                            struct backed_block* start, struct backed_block* end);
 
 #endif
diff --git a/libsparse/defs.h b/libsparse/defs.h
index 34e63c5..28e5cab 100644
--- a/libsparse/defs.h
+++ b/libsparse/defs.h
@@ -17,7 +17,7 @@
 #ifndef _LIBSPARSE_DEFS_H_
 
 #ifndef __unused
-#define __unused        __attribute__((__unused__))
+#define __unused __attribute__((__unused__))
 #endif
 
 #endif /* _LIBSPARSE_DEFS_H_ */
diff --git a/libsparse/img2simg.c b/libsparse/img2simg.c
deleted file mode 100644
index a0db36f..0000000
--- a/libsparse/img2simg.c
+++ /dev/null
@@ -1,115 +0,0 @@
-/*
- * Copyright (C) 2012 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#define _FILE_OFFSET_BITS 64
-#define _LARGEFILE64_SOURCE 1
-
-#include <fcntl.h>
-#include <stdbool.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <unistd.h>
-
-#include <sparse/sparse.h>
-
-#ifndef O_BINARY
-#define O_BINARY 0
-#endif
-
-#if defined(__APPLE__) && defined(__MACH__)
-#define lseek64 lseek
-#define off64_t off_t
-#endif
-
-void usage()
-{
-    fprintf(stderr, "Usage: img2simg <raw_image_file> <sparse_image_file> [<block_size>]\n");
-}
-
-int main(int argc, char *argv[])
-{
-	int in;
-	int out;
-	int ret;
-	struct sparse_file *s;
-	unsigned int block_size = 4096;
-	off64_t len;
-
-	if (argc < 3 || argc > 4) {
-		usage();
-		exit(-1);
-	}
-
-	if (argc == 4) {
-		block_size = atoi(argv[3]);
-	}
-
-	if (block_size < 1024 || block_size % 4 != 0) {
-		usage();
-		exit(-1);
-	}
-
-	if (strcmp(argv[1], "-") == 0) {
-		in = STDIN_FILENO;
-	} else {
-		in = open(argv[1], O_RDONLY | O_BINARY);
-		if (in < 0) {
-			fprintf(stderr, "Cannot open input file %s\n", argv[1]);
-			exit(-1);
-		}
-	}
-
-	if (strcmp(argv[2], "-") == 0) {
-		out = STDOUT_FILENO;
-	} else {
-		out = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0664);
-		if (out < 0) {
-			fprintf(stderr, "Cannot open output file %s\n", argv[2]);
-			exit(-1);
-		}
-	}
-
-	len = lseek64(in, 0, SEEK_END);
-	lseek64(in, 0, SEEK_SET);
-
-	s = sparse_file_new(block_size, len);
-	if (!s) {
-		fprintf(stderr, "Failed to create sparse file\n");
-		exit(-1);
-	}
-
-	sparse_file_verbose(s);
-	ret = sparse_file_read(s, in, false, false);
-	if (ret) {
-		fprintf(stderr, "Failed to read file\n");
-		exit(-1);
-	}
-
-	ret = sparse_file_write(s, out, false, true, false);
-	if (ret) {
-		fprintf(stderr, "Failed to write sparse file\n");
-		exit(-1);
-	}
-
-	close(in);
-	close(out);
-
-	exit(0);
-}
diff --git a/libsparse/img2simg.cpp b/libsparse/img2simg.cpp
new file mode 100644
index 0000000..4c2c6ca
--- /dev/null
+++ b/libsparse/img2simg.cpp
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define _FILE_OFFSET_BITS 64
+#define _LARGEFILE64_SOURCE 1
+
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <sparse/sparse.h>
+
+#ifndef O_BINARY
+#define O_BINARY 0
+#endif
+
+#if defined(__APPLE__) && defined(__MACH__)
+#define lseek64 lseek
+#define off64_t off_t
+#endif
+
+void usage() {
+  fprintf(stderr, "Usage: img2simg <raw_image_file> <sparse_image_file> [<block_size>]\n");
+}
+
+int main(int argc, char* argv[]) {
+  int in;
+  int out;
+  int ret;
+  struct sparse_file* s;
+  unsigned int block_size = 4096;
+  off64_t len;
+
+  if (argc < 3 || argc > 4) {
+    usage();
+    exit(-1);
+  }
+
+  if (argc == 4) {
+    block_size = atoi(argv[3]);
+  }
+
+  if (block_size < 1024 || block_size % 4 != 0) {
+    usage();
+    exit(-1);
+  }
+
+  if (strcmp(argv[1], "-") == 0) {
+    in = STDIN_FILENO;
+  } else {
+    in = open(argv[1], O_RDONLY | O_BINARY);
+    if (in < 0) {
+      fprintf(stderr, "Cannot open input file %s\n", argv[1]);
+      exit(-1);
+    }
+  }
+
+  if (strcmp(argv[2], "-") == 0) {
+    out = STDOUT_FILENO;
+  } else {
+    out = open(argv[2], O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0664);
+    if (out < 0) {
+      fprintf(stderr, "Cannot open output file %s\n", argv[2]);
+      exit(-1);
+    }
+  }
+
+  len = lseek64(in, 0, SEEK_END);
+  lseek64(in, 0, SEEK_SET);
+
+  s = sparse_file_new(block_size, len);
+  if (!s) {
+    fprintf(stderr, "Failed to create sparse file\n");
+    exit(-1);
+  }
+
+  sparse_file_verbose(s);
+  ret = sparse_file_read(s, in, false, false);
+  if (ret) {
+    fprintf(stderr, "Failed to read file\n");
+    exit(-1);
+  }
+
+  ret = sparse_file_write(s, out, false, true, false);
+  if (ret) {
+    fprintf(stderr, "Failed to write sparse file\n");
+    exit(-1);
+  }
+
+  close(in);
+  close(out);
+
+  exit(0);
+}
diff --git a/libsparse/include/sparse/sparse.h b/libsparse/include/sparse/sparse.h
index 1b91ead..3d5fb0c 100644
--- a/libsparse/include/sparse/sparse.h
+++ b/libsparse/include/sparse/sparse.h
@@ -246,9 +246,24 @@
 int sparse_file_read(struct sparse_file *s, int fd, bool sparse, bool crc);
 
 /**
- * sparse_file_import - import an existing sparse file
+ * sparse_file_read_buf - read a buffer into a sparse file cookie
  *
  * @s - sparse file cookie
+ * @buf - buffer to read from
+ * @crc - verify the crc of a file in the Android sparse file format
+ *
+ * Reads a buffer into a sparse file cookie. The buffer must remain
+ * valid until the sparse file cookie is freed. If crc is true, the
+ * crc of the sparse file will be verified.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int sparse_file_read_buf(struct sparse_file *s, char *buf, bool crc);
+
+/**
+ * sparse_file_import - import an existing sparse file
+ *
+ * @fd - file descriptor to read from
  * @verbose - print verbose errors while reading the sparse file
  * @crc - verify the crc of a file in the Android sparse file format
  *
@@ -261,6 +276,21 @@
 struct sparse_file *sparse_file_import(int fd, bool verbose, bool crc);
 
 /**
+ * sparse_file_import_buf - import an existing sparse file from a buffer
+ *
+ * @buf - buffer to read from
+ * @verbose - print verbose errors while reading the sparse file
+ * @crc - verify the crc of a file in the Android sparse file format
+ *
+ * Reads existing sparse file data into a sparse file cookie, recreating the same
+ * sparse cookie that was used to write it.  If verbose is true, prints verbose
+ * errors when the sparse file is formatted incorrectly.
+ *
+ * Returns a new sparse file cookie on success, NULL on error.
+ */
+struct sparse_file *sparse_file_import_buf(char* buf, bool verbose, bool crc);
+
+/**
  * sparse_file_import_auto - import an existing sparse or normal file
  *
  * @fd - file descriptor to read from
diff --git a/libsparse/output_file.c b/libsparse/output_file.c
deleted file mode 100644
index 002ad27..0000000
--- a/libsparse/output_file.c
+++ /dev/null
@@ -1,776 +0,0 @@
-/*
- * Copyright (C) 2010 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#define _FILE_OFFSET_BITS 64
-#define _LARGEFILE64_SOURCE 1
-
-#include <fcntl.h>
-#include <inttypes.h>
-#include <limits.h>
-#include <stdbool.h>
-#include <stddef.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <unistd.h>
-#include <zlib.h>
-
-#include "defs.h"
-#include "output_file.h"
-#include "sparse_crc32.h"
-#include "sparse_format.h"
-
-#ifndef _WIN32
-#include <sys/mman.h>
-#define O_BINARY 0
-#else
-#define ftruncate64 ftruncate
-#endif
-
-#if defined(__APPLE__) && defined(__MACH__)
-#define lseek64 lseek
-#define ftruncate64 ftruncate
-#define mmap64 mmap
-#define off64_t off_t
-#endif
-
-#define min(a, b) \
-	({ typeof(a) _a = (a); typeof(b) _b = (b); (_a < _b) ? _a : _b; })
-
-#define SPARSE_HEADER_MAJOR_VER 1
-#define SPARSE_HEADER_MINOR_VER 0
-#define SPARSE_HEADER_LEN       (sizeof(sparse_header_t))
-#define CHUNK_HEADER_LEN (sizeof(chunk_header_t))
-
-#define container_of(inner, outer_t, elem) \
-	((outer_t *)((char *)(inner) - offsetof(outer_t, elem)))
-
-struct output_file_ops {
-	int (*open)(struct output_file *, int fd);
-	int (*skip)(struct output_file *, int64_t);
-	int (*pad)(struct output_file *, int64_t);
-	int (*write)(struct output_file *, void *, size_t);
-	void (*close)(struct output_file *);
-};
-
-struct sparse_file_ops {
-	int (*write_data_chunk)(struct output_file *out, unsigned int len,
-			void *data);
-	int (*write_fill_chunk)(struct output_file *out, unsigned int len,
-			uint32_t fill_val);
-	int (*write_skip_chunk)(struct output_file *out, int64_t len);
-	int (*write_end_chunk)(struct output_file *out);
-};
-
-struct output_file {
-	int64_t cur_out_ptr;
-	unsigned int chunk_cnt;
-	uint32_t crc32;
-	struct output_file_ops *ops;
-	struct sparse_file_ops *sparse_ops;
-	int use_crc;
-	unsigned int block_size;
-	int64_t len;
-	char *zero_buf;
-	uint32_t *fill_buf;
-	char *buf;
-};
-
-struct output_file_gz {
-	struct output_file out;
-	gzFile gz_fd;
-};
-
-#define to_output_file_gz(_o) \
-	container_of((_o), struct output_file_gz, out)
-
-struct output_file_normal {
-	struct output_file out;
-	int fd;
-};
-
-#define to_output_file_normal(_o) \
-	container_of((_o), struct output_file_normal, out)
-
-struct output_file_callback {
-	struct output_file out;
-	void *priv;
-	int (*write)(void *priv, const void *buf, size_t len);
-};
-
-#define to_output_file_callback(_o) \
-	container_of((_o), struct output_file_callback, out)
-
-static int file_open(struct output_file *out, int fd)
-{
-	struct output_file_normal *outn = to_output_file_normal(out);
-
-	outn->fd = fd;
-	return 0;
-}
-
-static int file_skip(struct output_file *out, int64_t cnt)
-{
-	off64_t ret;
-	struct output_file_normal *outn = to_output_file_normal(out);
-
-	ret = lseek64(outn->fd, cnt, SEEK_CUR);
-	if (ret < 0) {
-		error_errno("lseek64");
-		return -1;
-	}
-	return 0;
-}
-
-static int file_pad(struct output_file *out, int64_t len)
-{
-	int ret;
-	struct output_file_normal *outn = to_output_file_normal(out);
-
-	ret = ftruncate64(outn->fd, len);
-	if (ret < 0) {
-		return -errno;
-	}
-
-	return 0;
-}
-
-static int file_write(struct output_file *out, void *data, size_t len)
-{
-	ssize_t ret;
-	struct output_file_normal *outn = to_output_file_normal(out);
-
-	while (len > 0) {
-		ret = write(outn->fd, data, len);
-		if (ret < 0) {
-			if (errno == EINTR) {
-				continue;
-			}
-			error_errno("write");
-			return -1;
-		}
-
-		data = (char *)data + ret;
-		len -= ret;
-	}
-
-	return 0;
-}
-
-static void file_close(struct output_file *out)
-{
-	struct output_file_normal *outn = to_output_file_normal(out);
-
-	free(outn);
-}
-
-static struct output_file_ops file_ops = {
-	.open = file_open,
-	.skip = file_skip,
-	.pad = file_pad,
-	.write = file_write,
-	.close = file_close,
-};
-
-static int gz_file_open(struct output_file *out, int fd)
-{
-	struct output_file_gz *outgz = to_output_file_gz(out);
-
-	outgz->gz_fd = gzdopen(fd, "wb9");
-	if (!outgz->gz_fd) {
-		error_errno("gzopen");
-		return -errno;
-	}
-
-	return 0;
-}
-
-
-static int gz_file_skip(struct output_file *out, int64_t cnt)
-{
-	off64_t ret;
-	struct output_file_gz *outgz = to_output_file_gz(out);
-
-	ret = gzseek(outgz->gz_fd, cnt, SEEK_CUR);
-	if (ret < 0) {
-		error_errno("gzseek");
-		return -1;
-	}
-	return 0;
-}
-
-static int gz_file_pad(struct output_file *out, int64_t len)
-{
-	off64_t ret;
-	struct output_file_gz *outgz = to_output_file_gz(out);
-
-	ret = gztell(outgz->gz_fd);
-	if (ret < 0) {
-		return -1;
-	}
-
-	if (ret >= len) {
-		return 0;
-	}
-
-	ret = gzseek(outgz->gz_fd, len - 1, SEEK_SET);
-	if (ret < 0) {
-		return -1;
-	}
-
-	gzwrite(outgz->gz_fd, "", 1);
-
-	return 0;
-}
-
-static int gz_file_write(struct output_file *out, void *data, size_t len)
-{
-	int ret;
-	struct output_file_gz *outgz = to_output_file_gz(out);
-
-	while (len > 0) {
-		ret = gzwrite(outgz->gz_fd, data,
-			      min(len, (unsigned int)INT_MAX));
-		if (ret == 0) {
-			error("gzwrite %s", gzerror(outgz->gz_fd, NULL));
-			return -1;
-		}
-		len -= ret;
-		data = (char *)data + ret;
-	}
-
-	return 0;
-}
-
-static void gz_file_close(struct output_file *out)
-{
-	struct output_file_gz *outgz = to_output_file_gz(out);
-
-	gzclose(outgz->gz_fd);
-	free(outgz);
-}
-
-static struct output_file_ops gz_file_ops = {
-	.open = gz_file_open,
-	.skip = gz_file_skip,
-	.pad = gz_file_pad,
-	.write = gz_file_write,
-	.close = gz_file_close,
-};
-
-static int callback_file_open(struct output_file *out __unused, int fd __unused)
-{
-	return 0;
-}
-
-static int callback_file_skip(struct output_file *out, int64_t off)
-{
-	struct output_file_callback *outc = to_output_file_callback(out);
-	int to_write;
-	int ret;
-
-	while (off > 0) {
-		to_write = min(off, (int64_t)INT_MAX);
-		ret = outc->write(outc->priv, NULL, to_write);
-		if (ret < 0) {
-			return ret;
-		}
-		off -= to_write;
-	}
-
-	return 0;
-}
-
-static int callback_file_pad(struct output_file *out __unused, int64_t len __unused)
-{
-	return -1;
-}
-
-static int callback_file_write(struct output_file *out, void *data, size_t len)
-{
-	struct output_file_callback *outc = to_output_file_callback(out);
-
-	return outc->write(outc->priv, data, len);
-}
-
-static void callback_file_close(struct output_file *out)
-{
-	struct output_file_callback *outc = to_output_file_callback(out);
-
-	free(outc);
-}
-
-static struct output_file_ops callback_file_ops = {
-	.open = callback_file_open,
-	.skip = callback_file_skip,
-	.pad = callback_file_pad,
-	.write = callback_file_write,
-	.close = callback_file_close,
-};
-
-int read_all(int fd, void *buf, size_t len)
-{
-	size_t total = 0;
-	int ret;
-	char *ptr = buf;
-
-	while (total < len) {
-		ret = read(fd, ptr, len - total);
-
-		if (ret < 0)
-			return -errno;
-
-		if (ret == 0)
-			return -EINVAL;
-
-		ptr += ret;
-		total += ret;
-	}
-
-	return 0;
-}
-
-static int write_sparse_skip_chunk(struct output_file *out, int64_t skip_len)
-{
-	chunk_header_t chunk_header;
-	int ret;
-
-	if (skip_len % out->block_size) {
-		error("don't care size %"PRIi64" is not a multiple of the block size %u",
-				skip_len, out->block_size);
-		return -1;
-	}
-
-	/* We are skipping data, so emit a don't care chunk. */
-	chunk_header.chunk_type = CHUNK_TYPE_DONT_CARE;
-	chunk_header.reserved1 = 0;
-	chunk_header.chunk_sz = skip_len / out->block_size;
-	chunk_header.total_sz = CHUNK_HEADER_LEN;
-	ret = out->ops->write(out, &chunk_header, sizeof(chunk_header));
-	if (ret < 0)
-		return -1;
-
-	out->cur_out_ptr += skip_len;
-	out->chunk_cnt++;
-
-	return 0;
-}
-
-static int write_sparse_fill_chunk(struct output_file *out, unsigned int len,
-		uint32_t fill_val)
-{
-	chunk_header_t chunk_header;
-	int rnd_up_len, count;
-	int ret;
-
-	/* Round up the fill length to a multiple of the block size */
-	rnd_up_len = ALIGN(len, out->block_size);
-
-	/* Finally we can safely emit a chunk of data */
-	chunk_header.chunk_type = CHUNK_TYPE_FILL;
-	chunk_header.reserved1 = 0;
-	chunk_header.chunk_sz = rnd_up_len / out->block_size;
-	chunk_header.total_sz = CHUNK_HEADER_LEN + sizeof(fill_val);
-	ret = out->ops->write(out, &chunk_header, sizeof(chunk_header));
-
-	if (ret < 0)
-		return -1;
-	ret = out->ops->write(out, &fill_val, sizeof(fill_val));
-	if (ret < 0)
-		return -1;
-
-	if (out->use_crc) {
-		count = out->block_size / sizeof(uint32_t);
-		while (count--)
-			out->crc32 = sparse_crc32(out->crc32, &fill_val, sizeof(uint32_t));
-	}
-
-	out->cur_out_ptr += rnd_up_len;
-	out->chunk_cnt++;
-
-	return 0;
-}
-
-static int write_sparse_data_chunk(struct output_file *out, unsigned int len,
-		void *data)
-{
-	chunk_header_t chunk_header;
-	int rnd_up_len, zero_len;
-	int ret;
-
-	/* Round up the data length to a multiple of the block size */
-	rnd_up_len = ALIGN(len, out->block_size);
-	zero_len = rnd_up_len - len;
-
-	/* Finally we can safely emit a chunk of data */
-	chunk_header.chunk_type = CHUNK_TYPE_RAW;
-	chunk_header.reserved1 = 0;
-	chunk_header.chunk_sz = rnd_up_len / out->block_size;
-	chunk_header.total_sz = CHUNK_HEADER_LEN + rnd_up_len;
-	ret = out->ops->write(out, &chunk_header, sizeof(chunk_header));
-
-	if (ret < 0)
-		return -1;
-	ret = out->ops->write(out, data, len);
-	if (ret < 0)
-		return -1;
-	if (zero_len) {
-		ret = out->ops->write(out, out->zero_buf, zero_len);
-		if (ret < 0)
-			return -1;
-	}
-
-	if (out->use_crc) {
-		out->crc32 = sparse_crc32(out->crc32, data, len);
-		if (zero_len)
-			out->crc32 = sparse_crc32(out->crc32, out->zero_buf, zero_len);
-	}
-
-	out->cur_out_ptr += rnd_up_len;
-	out->chunk_cnt++;
-
-	return 0;
-}
-
-int write_sparse_end_chunk(struct output_file *out)
-{
-	chunk_header_t chunk_header;
-	int ret;
-
-	if (out->use_crc) {
-		chunk_header.chunk_type = CHUNK_TYPE_CRC32;
-		chunk_header.reserved1 = 0;
-		chunk_header.chunk_sz = 0;
-		chunk_header.total_sz = CHUNK_HEADER_LEN + 4;
-
-		ret = out->ops->write(out, &chunk_header, sizeof(chunk_header));
-		if (ret < 0) {
-			return ret;
-		}
-		out->ops->write(out, &out->crc32, 4);
-		if (ret < 0) {
-			return ret;
-		}
-
-		out->chunk_cnt++;
-	}
-
-	return 0;
-}
-
-static struct sparse_file_ops sparse_file_ops = {
-		.write_data_chunk = write_sparse_data_chunk,
-		.write_fill_chunk = write_sparse_fill_chunk,
-		.write_skip_chunk = write_sparse_skip_chunk,
-		.write_end_chunk = write_sparse_end_chunk,
-};
-
-static int write_normal_data_chunk(struct output_file *out, unsigned int len,
-		void *data)
-{
-	int ret;
-	unsigned int rnd_up_len = ALIGN(len, out->block_size);
-
-	ret = out->ops->write(out, data, len);
-	if (ret < 0) {
-		return ret;
-	}
-
-	if (rnd_up_len > len) {
-		ret = out->ops->skip(out, rnd_up_len - len);
-	}
-
-	return ret;
-}
-
-static int write_normal_fill_chunk(struct output_file *out, unsigned int len,
-		uint32_t fill_val)
-{
-	int ret;
-	unsigned int i;
-	unsigned int write_len;
-
-	/* Initialize fill_buf with the fill_val */
-	for (i = 0; i < out->block_size / sizeof(uint32_t); i++) {
-		out->fill_buf[i] = fill_val;
-	}
-
-	while (len) {
-		write_len = min(len, out->block_size);
-		ret = out->ops->write(out, out->fill_buf, write_len);
-		if (ret < 0) {
-			return ret;
-		}
-
-		len -= write_len;
-	}
-
-	return 0;
-}
-
-static int write_normal_skip_chunk(struct output_file *out, int64_t len)
-{
-	return out->ops->skip(out, len);
-}
-
-int write_normal_end_chunk(struct output_file *out)
-{
-	return out->ops->pad(out, out->len);
-}
-
-static struct sparse_file_ops normal_file_ops = {
-		.write_data_chunk = write_normal_data_chunk,
-		.write_fill_chunk = write_normal_fill_chunk,
-		.write_skip_chunk = write_normal_skip_chunk,
-		.write_end_chunk = write_normal_end_chunk,
-};
-
-void output_file_close(struct output_file *out)
-{
-	out->sparse_ops->write_end_chunk(out);
-	out->ops->close(out);
-}
-
-static int output_file_init(struct output_file *out, int block_size,
-		int64_t len, bool sparse, int chunks, bool crc)
-{
-	int ret;
-
-	out->len = len;
-	out->block_size = block_size;
-	out->cur_out_ptr = 0ll;
-	out->chunk_cnt = 0;
-	out->crc32 = 0;
-	out->use_crc = crc;
-
-	out->zero_buf = calloc(block_size, 1);
-	if (!out->zero_buf) {
-		error_errno("malloc zero_buf");
-		return -ENOMEM;
-	}
-
-	out->fill_buf = calloc(block_size, 1);
-	if (!out->fill_buf) {
-		error_errno("malloc fill_buf");
-		ret = -ENOMEM;
-		goto err_fill_buf;
-	}
-
-	if (sparse) {
-		out->sparse_ops = &sparse_file_ops;
-	} else {
-		out->sparse_ops = &normal_file_ops;
-	}
-
-	if (sparse) {
-		sparse_header_t sparse_header = {
-				.magic = SPARSE_HEADER_MAGIC,
-				.major_version = SPARSE_HEADER_MAJOR_VER,
-				.minor_version = SPARSE_HEADER_MINOR_VER,
-				.file_hdr_sz = SPARSE_HEADER_LEN,
-				.chunk_hdr_sz = CHUNK_HEADER_LEN,
-				.blk_sz = out->block_size,
-				.total_blks = DIV_ROUND_UP(out->len, out->block_size),
-				.total_chunks = chunks,
-				.image_checksum = 0
-		};
-
-		if (out->use_crc) {
-			sparse_header.total_chunks++;
-		}
-
-		ret = out->ops->write(out, &sparse_header, sizeof(sparse_header));
-		if (ret < 0) {
-			goto err_write;
-		}
-	}
-
-	return 0;
-
-err_write:
-	free(out->fill_buf);
-err_fill_buf:
-	free(out->zero_buf);
-	return ret;
-}
-
-static struct output_file *output_file_new_gz(void)
-{
-	struct output_file_gz *outgz = calloc(1, sizeof(struct output_file_gz));
-	if (!outgz) {
-		error_errno("malloc struct outgz");
-		return NULL;
-	}
-
-	outgz->out.ops = &gz_file_ops;
-
-	return &outgz->out;
-}
-
-static struct output_file *output_file_new_normal(void)
-{
-	struct output_file_normal *outn = calloc(1, sizeof(struct output_file_normal));
-	if (!outn) {
-		error_errno("malloc struct outn");
-		return NULL;
-	}
-
-	outn->out.ops = &file_ops;
-
-	return &outn->out;
-}
-
-struct output_file *output_file_open_callback(
-		int (*write)(void *, const void *, size_t),
-		void *priv, unsigned int block_size, int64_t len,
-		int gz __unused, int sparse, int chunks, int crc)
-{
-	int ret;
-	struct output_file_callback *outc;
-
-	outc = calloc(1, sizeof(struct output_file_callback));
-	if (!outc) {
-		error_errno("malloc struct outc");
-		return NULL;
-	}
-
-	outc->out.ops = &callback_file_ops;
-	outc->priv = priv;
-	outc->write = write;
-
-	ret = output_file_init(&outc->out, block_size, len, sparse, chunks, crc);
-	if (ret < 0) {
-		free(outc);
-		return NULL;
-	}
-
-	return &outc->out;
-}
-
-struct output_file *output_file_open_fd(int fd, unsigned int block_size, int64_t len,
-		int gz, int sparse, int chunks, int crc)
-{
-	int ret;
-	struct output_file *out;
-
-	if (gz) {
-		out = output_file_new_gz();
-	} else {
-		out = output_file_new_normal();
-	}
-	if (!out) {
-		return NULL;
-	}
-
-	out->ops->open(out, fd);
-
-	ret = output_file_init(out, block_size, len, sparse, chunks, crc);
-	if (ret < 0) {
-		free(out);
-		return NULL;
-	}
-
-	return out;
-}
-
-/* Write a contiguous region of data blocks from a memory buffer */
-int write_data_chunk(struct output_file *out, unsigned int len, void *data)
-{
-	return out->sparse_ops->write_data_chunk(out, len, data);
-}
-
-/* Write a contiguous region of data blocks with a fill value */
-int write_fill_chunk(struct output_file *out, unsigned int len,
-		uint32_t fill_val)
-{
-	return out->sparse_ops->write_fill_chunk(out, len, fill_val);
-}
-
-int write_fd_chunk(struct output_file *out, unsigned int len,
-		int fd, int64_t offset)
-{
-	int ret;
-	int64_t aligned_offset;
-	int aligned_diff;
-	uint64_t buffer_size;
-	char *ptr;
-
-	aligned_offset = offset & ~(4096 - 1);
-	aligned_diff = offset - aligned_offset;
-	buffer_size = (uint64_t)len + (uint64_t)aligned_diff;
-
-#ifndef _WIN32
-	if (buffer_size > SIZE_MAX)
-		return -E2BIG;
-	char *data = mmap64(NULL, buffer_size, PROT_READ, MAP_SHARED, fd,
-			aligned_offset);
-	if (data == MAP_FAILED) {
-		return -errno;
-	}
-	ptr = data + aligned_diff;
-#else
-	off64_t pos;
-	char *data = malloc(len);
-	if (!data) {
-		return -errno;
-	}
-	pos = lseek64(fd, offset, SEEK_SET);
-	if (pos < 0) {
-                free(data);
-		return -errno;
-	}
-	ret = read_all(fd, data, len);
-	if (ret < 0) {
-                free(data);
-		return ret;
-	}
-	ptr = data;
-#endif
-
-	ret = out->sparse_ops->write_data_chunk(out, len, ptr);
-
-#ifndef _WIN32
-	munmap(data, buffer_size);
-#else
-	free(data);
-#endif
-
-	return ret;
-}
-
-/* Write a contiguous region of data blocks from a file */
-int write_file_chunk(struct output_file *out, unsigned int len,
-		const char *file, int64_t offset)
-{
-	int ret;
-
-	int file_fd = open(file, O_RDONLY | O_BINARY);
-	if (file_fd < 0) {
-		return -errno;
-	}
-
-	ret = write_fd_chunk(out, len, file_fd, offset);
-
-	close(file_fd);
-
-	return ret;
-}
-
-int write_skip_chunk(struct output_file *out, int64_t len)
-{
-	return out->sparse_ops->write_skip_chunk(out, len);
-}
diff --git a/libsparse/output_file.cpp b/libsparse/output_file.cpp
new file mode 100644
index 0000000..5388e77
--- /dev/null
+++ b/libsparse/output_file.cpp
@@ -0,0 +1,720 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define _FILE_OFFSET_BITS 64
+#define _LARGEFILE64_SOURCE 1
+
+#include <fcntl.h>
+#include <inttypes.h>
+#include <limits.h>
+#include <stdbool.h>
+#include <stddef.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+#include <zlib.h>
+
+#include "defs.h"
+#include "output_file.h"
+#include "sparse_crc32.h"
+#include "sparse_format.h"
+
+#ifndef _WIN32
+#include <sys/mman.h>
+#define O_BINARY 0
+#else
+#define ftruncate64 ftruncate
+#endif
+
+#if defined(__APPLE__) && defined(__MACH__)
+#define lseek64 lseek
+#define ftruncate64 ftruncate
+#define mmap64 mmap
+#define off64_t off_t
+#endif
+
+#define min(a, b)        \
+  ({                     \
+    typeof(a) _a = (a);  \
+    typeof(b) _b = (b);  \
+    (_a < _b) ? _a : _b; \
+  })
+
+#define SPARSE_HEADER_MAJOR_VER 1
+#define SPARSE_HEADER_MINOR_VER 0
+#define SPARSE_HEADER_LEN (sizeof(sparse_header_t))
+#define CHUNK_HEADER_LEN (sizeof(chunk_header_t))
+
+#define container_of(inner, outer_t, elem) ((outer_t*)((char*)(inner)-offsetof(outer_t, elem)))
+
+struct output_file_ops {
+  int (*open)(struct output_file*, int fd);
+  int (*skip)(struct output_file*, int64_t);
+  int (*pad)(struct output_file*, int64_t);
+  int (*write)(struct output_file*, void*, size_t);
+  void (*close)(struct output_file*);
+};
+
+struct sparse_file_ops {
+  int (*write_data_chunk)(struct output_file* out, unsigned int len, void* data);
+  int (*write_fill_chunk)(struct output_file* out, unsigned int len, uint32_t fill_val);
+  int (*write_skip_chunk)(struct output_file* out, int64_t len);
+  int (*write_end_chunk)(struct output_file* out);
+};
+
+struct output_file {
+  int64_t cur_out_ptr;
+  unsigned int chunk_cnt;
+  uint32_t crc32;
+  struct output_file_ops* ops;
+  struct sparse_file_ops* sparse_ops;
+  int use_crc;
+  unsigned int block_size;
+  int64_t len;
+  char* zero_buf;
+  uint32_t* fill_buf;
+  char* buf;
+};
+
+struct output_file_gz {
+  struct output_file out;
+  gzFile gz_fd;
+};
+
+#define to_output_file_gz(_o) container_of((_o), struct output_file_gz, out)
+
+struct output_file_normal {
+  struct output_file out;
+  int fd;
+};
+
+#define to_output_file_normal(_o) container_of((_o), struct output_file_normal, out)
+
+struct output_file_callback {
+  struct output_file out;
+  void* priv;
+  int (*write)(void* priv, const void* buf, size_t len);
+};
+
+#define to_output_file_callback(_o) container_of((_o), struct output_file_callback, out)
+
+static int file_open(struct output_file* out, int fd) {
+  struct output_file_normal* outn = to_output_file_normal(out);
+
+  outn->fd = fd;
+  return 0;
+}
+
+static int file_skip(struct output_file* out, int64_t cnt) {
+  off64_t ret;
+  struct output_file_normal* outn = to_output_file_normal(out);
+
+  ret = lseek64(outn->fd, cnt, SEEK_CUR);
+  if (ret < 0) {
+    error_errno("lseek64");
+    return -1;
+  }
+  return 0;
+}
+
+static int file_pad(struct output_file* out, int64_t len) {
+  int ret;
+  struct output_file_normal* outn = to_output_file_normal(out);
+
+  ret = ftruncate64(outn->fd, len);
+  if (ret < 0) {
+    return -errno;
+  }
+
+  return 0;
+}
+
+static int file_write(struct output_file* out, void* data, size_t len) {
+  ssize_t ret;
+  struct output_file_normal* outn = to_output_file_normal(out);
+
+  while (len > 0) {
+    ret = write(outn->fd, data, len);
+    if (ret < 0) {
+      if (errno == EINTR) {
+        continue;
+      }
+      error_errno("write");
+      return -1;
+    }
+
+    data = (char*)data + ret;
+    len -= ret;
+  }
+
+  return 0;
+}
+
+static void file_close(struct output_file* out) {
+  struct output_file_normal* outn = to_output_file_normal(out);
+
+  free(outn);
+}
+
+static struct output_file_ops file_ops = {
+    .open = file_open,
+    .skip = file_skip,
+    .pad = file_pad,
+    .write = file_write,
+    .close = file_close,
+};
+
+static int gz_file_open(struct output_file* out, int fd) {
+  struct output_file_gz* outgz = to_output_file_gz(out);
+
+  outgz->gz_fd = gzdopen(fd, "wb9");
+  if (!outgz->gz_fd) {
+    error_errno("gzopen");
+    return -errno;
+  }
+
+  return 0;
+}
+
+static int gz_file_skip(struct output_file* out, int64_t cnt) {
+  off64_t ret;
+  struct output_file_gz* outgz = to_output_file_gz(out);
+
+  ret = gzseek(outgz->gz_fd, cnt, SEEK_CUR);
+  if (ret < 0) {
+    error_errno("gzseek");
+    return -1;
+  }
+  return 0;
+}
+
+static int gz_file_pad(struct output_file* out, int64_t len) {
+  off64_t ret;
+  struct output_file_gz* outgz = to_output_file_gz(out);
+
+  ret = gztell(outgz->gz_fd);
+  if (ret < 0) {
+    return -1;
+  }
+
+  if (ret >= len) {
+    return 0;
+  }
+
+  ret = gzseek(outgz->gz_fd, len - 1, SEEK_SET);
+  if (ret < 0) {
+    return -1;
+  }
+
+  gzwrite(outgz->gz_fd, "", 1);
+
+  return 0;
+}
+
+static int gz_file_write(struct output_file* out, void* data, size_t len) {
+  int ret;
+  struct output_file_gz* outgz = to_output_file_gz(out);
+
+  while (len > 0) {
+    ret = gzwrite(outgz->gz_fd, data, min(len, (unsigned int)INT_MAX));
+    if (ret == 0) {
+      error("gzwrite %s", gzerror(outgz->gz_fd, NULL));
+      return -1;
+    }
+    len -= ret;
+    data = (char*)data + ret;
+  }
+
+  return 0;
+}
+
+static void gz_file_close(struct output_file* out) {
+  struct output_file_gz* outgz = to_output_file_gz(out);
+
+  gzclose(outgz->gz_fd);
+  free(outgz);
+}
+
+static struct output_file_ops gz_file_ops = {
+    .open = gz_file_open,
+    .skip = gz_file_skip,
+    .pad = gz_file_pad,
+    .write = gz_file_write,
+    .close = gz_file_close,
+};
+
+static int callback_file_open(struct output_file* out __unused, int fd __unused) {
+  return 0;
+}
+
+static int callback_file_skip(struct output_file* out, int64_t off) {
+  struct output_file_callback* outc = to_output_file_callback(out);
+  int to_write;
+  int ret;
+
+  while (off > 0) {
+    to_write = min(off, (int64_t)INT_MAX);
+    ret = outc->write(outc->priv, NULL, to_write);
+    if (ret < 0) {
+      return ret;
+    }
+    off -= to_write;
+  }
+
+  return 0;
+}
+
+static int callback_file_pad(struct output_file* out __unused, int64_t len __unused) {
+  return -1;
+}
+
+static int callback_file_write(struct output_file* out, void* data, size_t len) {
+  struct output_file_callback* outc = to_output_file_callback(out);
+
+  return outc->write(outc->priv, data, len);
+}
+
+static void callback_file_close(struct output_file* out) {
+  struct output_file_callback* outc = to_output_file_callback(out);
+
+  free(outc);
+}
+
+static struct output_file_ops callback_file_ops = {
+    .open = callback_file_open,
+    .skip = callback_file_skip,
+    .pad = callback_file_pad,
+    .write = callback_file_write,
+    .close = callback_file_close,
+};
+
+int read_all(int fd, void* buf, size_t len) {
+  size_t total = 0;
+  int ret;
+  char* ptr = reinterpret_cast<char*>(buf);
+
+  while (total < len) {
+    ret = read(fd, ptr, len - total);
+
+    if (ret < 0) return -errno;
+
+    if (ret == 0) return -EINVAL;
+
+    ptr += ret;
+    total += ret;
+  }
+
+  return 0;
+}
+
+static int write_sparse_skip_chunk(struct output_file* out, int64_t skip_len) {
+  chunk_header_t chunk_header;
+  int ret;
+
+  if (skip_len % out->block_size) {
+    error("don't care size %" PRIi64 " is not a multiple of the block size %u", skip_len,
+          out->block_size);
+    return -1;
+  }
+
+  /* We are skipping data, so emit a don't care chunk. */
+  chunk_header.chunk_type = CHUNK_TYPE_DONT_CARE;
+  chunk_header.reserved1 = 0;
+  chunk_header.chunk_sz = skip_len / out->block_size;
+  chunk_header.total_sz = CHUNK_HEADER_LEN;
+  ret = out->ops->write(out, &chunk_header, sizeof(chunk_header));
+  if (ret < 0) return -1;
+
+  out->cur_out_ptr += skip_len;
+  out->chunk_cnt++;
+
+  return 0;
+}
+
+static int write_sparse_fill_chunk(struct output_file* out, unsigned int len, uint32_t fill_val) {
+  chunk_header_t chunk_header;
+  int rnd_up_len, count;
+  int ret;
+
+  /* Round up the fill length to a multiple of the block size */
+  rnd_up_len = ALIGN(len, out->block_size);
+
+  /* Finally we can safely emit a chunk of data */
+  chunk_header.chunk_type = CHUNK_TYPE_FILL;
+  chunk_header.reserved1 = 0;
+  chunk_header.chunk_sz = rnd_up_len / out->block_size;
+  chunk_header.total_sz = CHUNK_HEADER_LEN + sizeof(fill_val);
+  ret = out->ops->write(out, &chunk_header, sizeof(chunk_header));
+
+  if (ret < 0) return -1;
+  ret = out->ops->write(out, &fill_val, sizeof(fill_val));
+  if (ret < 0) return -1;
+
+  if (out->use_crc) {
+    count = out->block_size / sizeof(uint32_t);
+    while (count--) out->crc32 = sparse_crc32(out->crc32, &fill_val, sizeof(uint32_t));
+  }
+
+  out->cur_out_ptr += rnd_up_len;
+  out->chunk_cnt++;
+
+  return 0;
+}
+
+static int write_sparse_data_chunk(struct output_file* out, unsigned int len, void* data) {
+  chunk_header_t chunk_header;
+  int rnd_up_len, zero_len;
+  int ret;
+
+  /* Round up the data length to a multiple of the block size */
+  rnd_up_len = ALIGN(len, out->block_size);
+  zero_len = rnd_up_len - len;
+
+  /* Finally we can safely emit a chunk of data */
+  chunk_header.chunk_type = CHUNK_TYPE_RAW;
+  chunk_header.reserved1 = 0;
+  chunk_header.chunk_sz = rnd_up_len / out->block_size;
+  chunk_header.total_sz = CHUNK_HEADER_LEN + rnd_up_len;
+  ret = out->ops->write(out, &chunk_header, sizeof(chunk_header));
+
+  if (ret < 0) return -1;
+  ret = out->ops->write(out, data, len);
+  if (ret < 0) return -1;
+  if (zero_len) {
+    ret = out->ops->write(out, out->zero_buf, zero_len);
+    if (ret < 0) return -1;
+  }
+
+  if (out->use_crc) {
+    out->crc32 = sparse_crc32(out->crc32, data, len);
+    if (zero_len) out->crc32 = sparse_crc32(out->crc32, out->zero_buf, zero_len);
+  }
+
+  out->cur_out_ptr += rnd_up_len;
+  out->chunk_cnt++;
+
+  return 0;
+}
+
+int write_sparse_end_chunk(struct output_file* out) {
+  chunk_header_t chunk_header;
+  int ret;
+
+  if (out->use_crc) {
+    chunk_header.chunk_type = CHUNK_TYPE_CRC32;
+    chunk_header.reserved1 = 0;
+    chunk_header.chunk_sz = 0;
+    chunk_header.total_sz = CHUNK_HEADER_LEN + 4;
+
+    ret = out->ops->write(out, &chunk_header, sizeof(chunk_header));
+    if (ret < 0) {
+      return ret;
+    }
+    out->ops->write(out, &out->crc32, 4);
+    if (ret < 0) {
+      return ret;
+    }
+
+    out->chunk_cnt++;
+  }
+
+  return 0;
+}
+
+static struct sparse_file_ops sparse_file_ops = {
+    .write_data_chunk = write_sparse_data_chunk,
+    .write_fill_chunk = write_sparse_fill_chunk,
+    .write_skip_chunk = write_sparse_skip_chunk,
+    .write_end_chunk = write_sparse_end_chunk,
+};
+
+static int write_normal_data_chunk(struct output_file* out, unsigned int len, void* data) {
+  int ret;
+  unsigned int rnd_up_len = ALIGN(len, out->block_size);
+
+  ret = out->ops->write(out, data, len);
+  if (ret < 0) {
+    return ret;
+  }
+
+  if (rnd_up_len > len) {
+    ret = out->ops->skip(out, rnd_up_len - len);
+  }
+
+  return ret;
+}
+
+static int write_normal_fill_chunk(struct output_file* out, unsigned int len, uint32_t fill_val) {
+  int ret;
+  unsigned int i;
+  unsigned int write_len;
+
+  /* Initialize fill_buf with the fill_val */
+  for (i = 0; i < out->block_size / sizeof(uint32_t); i++) {
+    out->fill_buf[i] = fill_val;
+  }
+
+  while (len) {
+    write_len = min(len, out->block_size);
+    ret = out->ops->write(out, out->fill_buf, write_len);
+    if (ret < 0) {
+      return ret;
+    }
+
+    len -= write_len;
+  }
+
+  return 0;
+}
+
+static int write_normal_skip_chunk(struct output_file* out, int64_t len) {
+  return out->ops->skip(out, len);
+}
+
+int write_normal_end_chunk(struct output_file* out) {
+  return out->ops->pad(out, out->len);
+}
+
+static struct sparse_file_ops normal_file_ops = {
+    .write_data_chunk = write_normal_data_chunk,
+    .write_fill_chunk = write_normal_fill_chunk,
+    .write_skip_chunk = write_normal_skip_chunk,
+    .write_end_chunk = write_normal_end_chunk,
+};
+
+void output_file_close(struct output_file* out) {
+  out->sparse_ops->write_end_chunk(out);
+  out->ops->close(out);
+}
+
+static int output_file_init(struct output_file* out, int block_size, int64_t len, bool sparse,
+                            int chunks, bool crc) {
+  int ret;
+
+  out->len = len;
+  out->block_size = block_size;
+  out->cur_out_ptr = 0ll;
+  out->chunk_cnt = 0;
+  out->crc32 = 0;
+  out->use_crc = crc;
+
+  out->zero_buf = reinterpret_cast<char*>(calloc(block_size, 1));
+  if (!out->zero_buf) {
+    error_errno("malloc zero_buf");
+    return -ENOMEM;
+  }
+
+  out->fill_buf = reinterpret_cast<uint32_t*>(calloc(block_size, 1));
+  if (!out->fill_buf) {
+    error_errno("malloc fill_buf");
+    ret = -ENOMEM;
+    goto err_fill_buf;
+  }
+
+  if (sparse) {
+    out->sparse_ops = &sparse_file_ops;
+  } else {
+    out->sparse_ops = &normal_file_ops;
+  }
+
+  if (sparse) {
+    sparse_header_t sparse_header = {
+        .magic = SPARSE_HEADER_MAGIC,
+        .major_version = SPARSE_HEADER_MAJOR_VER,
+        .minor_version = SPARSE_HEADER_MINOR_VER,
+        .file_hdr_sz = SPARSE_HEADER_LEN,
+        .chunk_hdr_sz = CHUNK_HEADER_LEN,
+        .blk_sz = out->block_size,
+        .total_blks = static_cast<unsigned>(DIV_ROUND_UP(out->len, out->block_size)),
+        .total_chunks = static_cast<unsigned>(chunks),
+        .image_checksum = 0};
+
+    if (out->use_crc) {
+      sparse_header.total_chunks++;
+    }
+
+    ret = out->ops->write(out, &sparse_header, sizeof(sparse_header));
+    if (ret < 0) {
+      goto err_write;
+    }
+  }
+
+  return 0;
+
+err_write:
+  free(out->fill_buf);
+err_fill_buf:
+  free(out->zero_buf);
+  return ret;
+}
+
+static struct output_file* output_file_new_gz(void) {
+  struct output_file_gz* outgz =
+      reinterpret_cast<struct output_file_gz*>(calloc(1, sizeof(struct output_file_gz)));
+  if (!outgz) {
+    error_errno("malloc struct outgz");
+    return NULL;
+  }
+
+  outgz->out.ops = &gz_file_ops;
+
+  return &outgz->out;
+}
+
+static struct output_file* output_file_new_normal(void) {
+  struct output_file_normal* outn =
+      reinterpret_cast<struct output_file_normal*>(calloc(1, sizeof(struct output_file_normal)));
+  if (!outn) {
+    error_errno("malloc struct outn");
+    return NULL;
+  }
+
+  outn->out.ops = &file_ops;
+
+  return &outn->out;
+}
+
+struct output_file* output_file_open_callback(int (*write)(void*, const void*, size_t), void* priv,
+                                              unsigned int block_size, int64_t len, int gz __unused,
+                                              int sparse, int chunks, int crc) {
+  int ret;
+  struct output_file_callback* outc;
+
+  outc =
+      reinterpret_cast<struct output_file_callback*>(calloc(1, sizeof(struct output_file_callback)));
+  if (!outc) {
+    error_errno("malloc struct outc");
+    return NULL;
+  }
+
+  outc->out.ops = &callback_file_ops;
+  outc->priv = priv;
+  outc->write = write;
+
+  ret = output_file_init(&outc->out, block_size, len, sparse, chunks, crc);
+  if (ret < 0) {
+    free(outc);
+    return NULL;
+  }
+
+  return &outc->out;
+}
+
+struct output_file* output_file_open_fd(int fd, unsigned int block_size, int64_t len, int gz,
+                                        int sparse, int chunks, int crc) {
+  int ret;
+  struct output_file* out;
+
+  if (gz) {
+    out = output_file_new_gz();
+  } else {
+    out = output_file_new_normal();
+  }
+  if (!out) {
+    return NULL;
+  }
+
+  out->ops->open(out, fd);
+
+  ret = output_file_init(out, block_size, len, sparse, chunks, crc);
+  if (ret < 0) {
+    free(out);
+    return NULL;
+  }
+
+  return out;
+}
+
+/* Write a contiguous region of data blocks from a memory buffer */
+int write_data_chunk(struct output_file* out, unsigned int len, void* data) {
+  return out->sparse_ops->write_data_chunk(out, len, data);
+}
+
+/* Write a contiguous region of data blocks with a fill value */
+int write_fill_chunk(struct output_file* out, unsigned int len, uint32_t fill_val) {
+  return out->sparse_ops->write_fill_chunk(out, len, fill_val);
+}
+
+int write_fd_chunk(struct output_file* out, unsigned int len, int fd, int64_t offset) {
+  int ret;
+  int64_t aligned_offset;
+  int aligned_diff;
+  uint64_t buffer_size;
+  char* ptr;
+
+  aligned_offset = offset & ~(4096 - 1);
+  aligned_diff = offset - aligned_offset;
+  buffer_size = (uint64_t)len + (uint64_t)aligned_diff;
+
+#ifndef _WIN32
+  if (buffer_size > SIZE_MAX) return -E2BIG;
+  char* data =
+      reinterpret_cast<char*>(mmap64(NULL, buffer_size, PROT_READ, MAP_SHARED, fd, aligned_offset));
+  if (data == MAP_FAILED) {
+    return -errno;
+  }
+  ptr = data + aligned_diff;
+#else
+  off64_t pos;
+  char* data = reinterpret_cast<char*>(malloc(len));
+  if (!data) {
+    return -errno;
+  }
+  pos = lseek64(fd, offset, SEEK_SET);
+  if (pos < 0) {
+    free(data);
+    return -errno;
+  }
+  ret = read_all(fd, data, len);
+  if (ret < 0) {
+    free(data);
+    return ret;
+  }
+  ptr = data;
+#endif
+
+  ret = out->sparse_ops->write_data_chunk(out, len, ptr);
+
+#ifndef _WIN32
+  munmap(data, buffer_size);
+#else
+  free(data);
+#endif
+
+  return ret;
+}
+
+/* Write a contiguous region of data blocks from a file */
+int write_file_chunk(struct output_file* out, unsigned int len, const char* file, int64_t offset) {
+  int ret;
+
+  int file_fd = open(file, O_RDONLY | O_BINARY);
+  if (file_fd < 0) {
+    return -errno;
+  }
+
+  ret = write_fd_chunk(out, len, file_fd, offset);
+
+  close(file_fd);
+
+  return ret;
+}
+
+int write_skip_chunk(struct output_file* out, int64_t len) {
+  return out->sparse_ops->write_skip_chunk(out, len);
+}
diff --git a/libsparse/output_file.h b/libsparse/output_file.h
index 690f610..278430b 100644
--- a/libsparse/output_file.h
+++ b/libsparse/output_file.h
@@ -25,23 +25,19 @@
 
 struct output_file;
 
-struct output_file *output_file_open_fd(int fd, unsigned int block_size, int64_t len,
-		int gz, int sparse, int chunks, int crc);
-struct output_file *output_file_open_callback(
-		int (*write)(void *, const void *, size_t),
-		void *priv, unsigned int block_size, int64_t len, int gz, int sparse,
-		int chunks, int crc);
-int write_data_chunk(struct output_file *out, unsigned int len, void *data);
-int write_fill_chunk(struct output_file *out, unsigned int len,
-		uint32_t fill_val);
-int write_file_chunk(struct output_file *out, unsigned int len,
-		const char *file, int64_t offset);
-int write_fd_chunk(struct output_file *out, unsigned int len,
-		int fd, int64_t offset);
-int write_skip_chunk(struct output_file *out, int64_t len);
-void output_file_close(struct output_file *out);
+struct output_file* output_file_open_fd(int fd, unsigned int block_size, int64_t len, int gz,
+                                        int sparse, int chunks, int crc);
+struct output_file* output_file_open_callback(int (*write)(void*, const void*, size_t), void* priv,
+                                              unsigned int block_size, int64_t len, int gz,
+                                              int sparse, int chunks, int crc);
+int write_data_chunk(struct output_file* out, unsigned int len, void* data);
+int write_fill_chunk(struct output_file* out, unsigned int len, uint32_t fill_val);
+int write_file_chunk(struct output_file* out, unsigned int len, const char* file, int64_t offset);
+int write_fd_chunk(struct output_file* out, unsigned int len, int fd, int64_t offset);
+int write_skip_chunk(struct output_file* out, int64_t len);
+void output_file_close(struct output_file* out);
 
-int read_all(int fd, void *buf, size_t len);
+int read_all(int fd, void* buf, size_t len);
 
 #ifdef __cplusplus
 }
diff --git a/libsparse/simg2img.c b/libsparse/simg2img.c
deleted file mode 100644
index b9b438e..0000000
--- a/libsparse/simg2img.c
+++ /dev/null
@@ -1,90 +0,0 @@
-/*
- * Copyright (C) 2010 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include <sparse/sparse.h>
-
-#include <fcntl.h>
-#include <stdbool.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <unistd.h>
-
-#ifndef O_BINARY
-#define O_BINARY 0
-#endif
-
-void usage()
-{
-  fprintf(stderr, "Usage: simg2img <sparse_image_files> <raw_image_file>\n");
-}
-
-int main(int argc, char *argv[])
-{
-	int in;
-	int out;
-	int i;
-	struct sparse_file *s;
-
-	if (argc < 3) {
-		usage();
-		exit(-1);
-	}
-
-	out = open(argv[argc - 1], O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0664);
-	if (out < 0) {
-		fprintf(stderr, "Cannot open output file %s\n", argv[argc - 1]);
-		exit(-1);
-	}
-
-	for (i = 1; i < argc - 1; i++) {
-		if (strcmp(argv[i], "-") == 0) {
-			in = STDIN_FILENO;
-		} else {
-			in = open(argv[i], O_RDONLY | O_BINARY);
-			if (in < 0) {
-				fprintf(stderr, "Cannot open input file %s\n", argv[i]);
-				exit(-1);
-			}
-		}
-
-		s = sparse_file_import(in, true, false);
-		if (!s) {
-			fprintf(stderr, "Failed to read sparse file\n");
-			exit(-1);
-		}
-
-		if (lseek(out, 0, SEEK_SET) == -1) {
-			perror("lseek failed");
-			exit(EXIT_FAILURE);
-		}
-
-		if (sparse_file_write(s, out, false, false, false) < 0) {
-			fprintf(stderr, "Cannot write output file\n");
-			exit(-1);
-		}
-		sparse_file_destroy(s);
-		close(in);
-	}
-
-	close(out);
-
-	exit(0);
-}
-
diff --git a/libsparse/simg2img.cpp b/libsparse/simg2img.cpp
new file mode 100644
index 0000000..8ba5f69
--- /dev/null
+++ b/libsparse/simg2img.cpp
@@ -0,0 +1,86 @@
+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <sparse/sparse.h>
+
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#ifndef O_BINARY
+#define O_BINARY 0
+#endif
+
+void usage() {
+  fprintf(stderr, "Usage: simg2img <sparse_image_files> <raw_image_file>\n");
+}
+
+int main(int argc, char* argv[]) {
+  int in;
+  int out;
+  int i;
+  struct sparse_file* s;
+
+  if (argc < 3) {
+    usage();
+    exit(-1);
+  }
+
+  out = open(argv[argc - 1], O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0664);
+  if (out < 0) {
+    fprintf(stderr, "Cannot open output file %s\n", argv[argc - 1]);
+    exit(-1);
+  }
+
+  for (i = 1; i < argc - 1; i++) {
+    if (strcmp(argv[i], "-") == 0) {
+      in = STDIN_FILENO;
+    } else {
+      in = open(argv[i], O_RDONLY | O_BINARY);
+      if (in < 0) {
+        fprintf(stderr, "Cannot open input file %s\n", argv[i]);
+        exit(-1);
+      }
+    }
+
+    s = sparse_file_import(in, true, false);
+    if (!s) {
+      fprintf(stderr, "Failed to read sparse file\n");
+      exit(-1);
+    }
+
+    if (lseek(out, 0, SEEK_SET) == -1) {
+      perror("lseek failed");
+      exit(EXIT_FAILURE);
+    }
+
+    if (sparse_file_write(s, out, false, false, false) < 0) {
+      fprintf(stderr, "Cannot write output file\n");
+      exit(-1);
+    }
+    sparse_file_destroy(s);
+    close(in);
+  }
+
+  close(out);
+
+  exit(0);
+}
diff --git a/libsparse/simg2simg.c b/libsparse/simg2simg.c
deleted file mode 100644
index 5f9ccf6..0000000
--- a/libsparse/simg2simg.c
+++ /dev/null
@@ -1,115 +0,0 @@
-/*
- * Copyright (C) 2012 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#define _FILE_OFFSET_BITS 64
-#define _LARGEFILE64_SOURCE 1
-#define _GNU_SOURCE
-
-#include <fcntl.h>
-#include <stdbool.h>
-#include <stdio.h>
-#include <stdlib.h>
-#include <string.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include <sys/types.h>
-#include <unistd.h>
-
-#include <sparse/sparse.h>
-
-#ifndef O_BINARY
-#define O_BINARY 0
-#endif
-
-void usage()
-{
-  fprintf(stderr, "Usage: simg2simg <sparse image file> <sparse_image_file> <max_size>\n");
-}
-
-int main(int argc, char *argv[])
-{
-	int in;
-	int out;
-	int i;
-	int ret;
-	struct sparse_file *s;
-	int64_t max_size;
-	struct sparse_file **out_s;
-	int files;
-	char filename[4096];
-
-	if (argc != 4) {
-		usage();
-		exit(-1);
-	}
-
-	max_size = atoll(argv[3]);
-
-	in = open(argv[1], O_RDONLY | O_BINARY);
-	if (in < 0) {
-		fprintf(stderr, "Cannot open input file %s\n", argv[1]);
-		exit(-1);
-	}
-
-	s = sparse_file_import(in, true, false);
-	if (!s) {
-		fprintf(stderr, "Failed to import sparse file\n");
-		exit(-1);
-	}
-
-	files = sparse_file_resparse(s, max_size, NULL, 0);
-	if (files < 0) {
-		fprintf(stderr, "Failed to resparse\n");
-		exit(-1);
-	}
-
-	out_s = calloc(sizeof(struct sparse_file *), files);
-	if (!out_s) {
-		fprintf(stderr, "Failed to allocate sparse file array\n");
-		exit(-1);
-	}
-
-	files = sparse_file_resparse(s, max_size, out_s, files);
-	if (files < 0) {
-		fprintf(stderr, "Failed to resparse\n");
-		exit(-1);
-	}
-
-	for (i = 0; i < files; i++) {
-		ret = snprintf(filename, sizeof(filename), "%s.%d", argv[2], i);
-		if (ret >= (int)sizeof(filename)) {
-			fprintf(stderr, "Filename too long\n");
-			exit(-1);
-		}
-
-		out = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0664);
-		if (out < 0) {
-			fprintf(stderr, "Cannot open output file %s\n", argv[2]);
-			exit(-1);
-		}
-
-		ret = sparse_file_write(out_s[i], out, false, true, false);
-		if (ret) {
-			fprintf(stderr, "Failed to write sparse file\n");
-			exit(-1);
-		}
-		close(out);
-	}
-
-	close(in);
-
-	exit(0);
-}
diff --git a/libsparse/simg2simg.cpp b/libsparse/simg2simg.cpp
new file mode 100644
index 0000000..7e65701
--- /dev/null
+++ b/libsparse/simg2simg.cpp
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#define _FILE_OFFSET_BITS 64
+#define _LARGEFILE64_SOURCE 1
+
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#include <sparse/sparse.h>
+
+#ifndef O_BINARY
+#define O_BINARY 0
+#endif
+
+void usage() {
+  fprintf(stderr, "Usage: simg2simg <sparse image file> <sparse_image_file> <max_size>\n");
+}
+
+int main(int argc, char* argv[]) {
+  int in;
+  int out;
+  int i;
+  int ret;
+  struct sparse_file* s;
+  int64_t max_size;
+  struct sparse_file** out_s;
+  int files;
+  char filename[4096];
+
+  if (argc != 4) {
+    usage();
+    exit(-1);
+  }
+
+  max_size = atoll(argv[3]);
+
+  in = open(argv[1], O_RDONLY | O_BINARY);
+  if (in < 0) {
+    fprintf(stderr, "Cannot open input file %s\n", argv[1]);
+    exit(-1);
+  }
+
+  s = sparse_file_import(in, true, false);
+  if (!s) {
+    fprintf(stderr, "Failed to import sparse file\n");
+    exit(-1);
+  }
+
+  files = sparse_file_resparse(s, max_size, NULL, 0);
+  if (files < 0) {
+    fprintf(stderr, "Failed to resparse\n");
+    exit(-1);
+  }
+
+  out_s = calloc(sizeof(struct sparse_file*), files);
+  if (!out_s) {
+    fprintf(stderr, "Failed to allocate sparse file array\n");
+    exit(-1);
+  }
+
+  files = sparse_file_resparse(s, max_size, out_s, files);
+  if (files < 0) {
+    fprintf(stderr, "Failed to resparse\n");
+    exit(-1);
+  }
+
+  for (i = 0; i < files; i++) {
+    ret = snprintf(filename, sizeof(filename), "%s.%d", argv[2], i);
+    if (ret >= (int)sizeof(filename)) {
+      fprintf(stderr, "Filename too long\n");
+      exit(-1);
+    }
+
+    out = open(filename, O_WRONLY | O_CREAT | O_TRUNC | O_BINARY, 0664);
+    if (out < 0) {
+      fprintf(stderr, "Cannot open output file %s\n", argv[2]);
+      exit(-1);
+    }
+
+    ret = sparse_file_write(out_s[i], out, false, true, false);
+    if (ret) {
+      fprintf(stderr, "Failed to write sparse file\n");
+      exit(-1);
+    }
+    close(out);
+  }
+
+  close(in);
+
+  exit(0);
+}
diff --git a/libsparse/sparse.c b/libsparse/sparse.c
deleted file mode 100644
index 466435f..0000000
--- a/libsparse/sparse.c
+++ /dev/null
@@ -1,395 +0,0 @@
-/*
- * Copyright (C) 2012 The Android Open Source Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-#include <assert.h>
-#include <stdlib.h>
-
-#include <sparse/sparse.h>
-
-#include "defs.h"
-#include "sparse_file.h"
-
-#include "output_file.h"
-#include "backed_block.h"
-#include "sparse_defs.h"
-#include "sparse_format.h"
-
-struct sparse_file *sparse_file_new(unsigned int block_size, int64_t len)
-{
-	struct sparse_file *s = calloc(sizeof(struct sparse_file), 1);
-	if (!s) {
-		return NULL;
-	}
-
-	s->backed_block_list = backed_block_list_new(block_size);
-	if (!s->backed_block_list) {
-		free(s);
-		return NULL;
-	}
-
-	s->block_size = block_size;
-	s->len = len;
-
-	return s;
-}
-
-void sparse_file_destroy(struct sparse_file *s)
-{
-	backed_block_list_destroy(s->backed_block_list);
-	free(s);
-}
-
-int sparse_file_add_data(struct sparse_file *s,
-		void *data, unsigned int len, unsigned int block)
-{
-	return backed_block_add_data(s->backed_block_list, data, len, block);
-}
-
-int sparse_file_add_fill(struct sparse_file *s,
-		uint32_t fill_val, unsigned int len, unsigned int block)
-{
-	return backed_block_add_fill(s->backed_block_list, fill_val, len, block);
-}
-
-int sparse_file_add_file(struct sparse_file *s,
-		const char *filename, int64_t file_offset, unsigned int len,
-		unsigned int block)
-{
-	return backed_block_add_file(s->backed_block_list, filename, file_offset,
-			len, block);
-}
-
-int sparse_file_add_fd(struct sparse_file *s,
-		int fd, int64_t file_offset, unsigned int len, unsigned int block)
-{
-	return backed_block_add_fd(s->backed_block_list, fd, file_offset,
-			len, block);
-}
-unsigned int sparse_count_chunks(struct sparse_file *s)
-{
-	struct backed_block *bb;
-	unsigned int last_block = 0;
-	unsigned int chunks = 0;
-
-	for (bb = backed_block_iter_new(s->backed_block_list); bb;
-			bb = backed_block_iter_next(bb)) {
-		if (backed_block_block(bb) > last_block) {
-			/* If there is a gap between chunks, add a skip chunk */
-			chunks++;
-		}
-		chunks++;
-		last_block = backed_block_block(bb) +
-				DIV_ROUND_UP(backed_block_len(bb), s->block_size);
-	}
-	if (last_block < DIV_ROUND_UP(s->len, s->block_size)) {
-		chunks++;
-	}
-
-	return chunks;
-}
-
-static int sparse_file_write_block(struct output_file *out,
-		struct backed_block *bb)
-{
-	int ret = -EINVAL;
-
-	switch (backed_block_type(bb)) {
-	case BACKED_BLOCK_DATA:
-		ret = write_data_chunk(out, backed_block_len(bb), backed_block_data(bb));
-		break;
-	case BACKED_BLOCK_FILE:
-		ret = write_file_chunk(out, backed_block_len(bb),
-				       backed_block_filename(bb),
-				       backed_block_file_offset(bb));
-		break;
-	case BACKED_BLOCK_FD:
-		ret = write_fd_chunk(out, backed_block_len(bb),
-				     backed_block_fd(bb),
-				     backed_block_file_offset(bb));
-		break;
-	case BACKED_BLOCK_FILL:
-		ret = write_fill_chunk(out, backed_block_len(bb),
-				       backed_block_fill_val(bb));
-		break;
-	}
-
-	return ret;
-}
-
-static int write_all_blocks(struct sparse_file *s, struct output_file *out)
-{
-	struct backed_block *bb;
-	unsigned int last_block = 0;
-	int64_t pad;
-	int ret = 0;
-
-	for (bb = backed_block_iter_new(s->backed_block_list); bb;
-			bb = backed_block_iter_next(bb)) {
-		if (backed_block_block(bb) > last_block) {
-			unsigned int blocks = backed_block_block(bb) - last_block;
-			write_skip_chunk(out, (int64_t)blocks * s->block_size);
-		}
-		ret = sparse_file_write_block(out, bb);
-		if (ret)
-			return ret;
-		last_block = backed_block_block(bb) +
-				DIV_ROUND_UP(backed_block_len(bb), s->block_size);
-	}
-
-	pad = s->len - (int64_t)last_block * s->block_size;
-	assert(pad >= 0);
-	if (pad > 0) {
-		write_skip_chunk(out, pad);
-	}
-
-	return 0;
-}
-
-int sparse_file_write(struct sparse_file *s, int fd, bool gz, bool sparse,
-		bool crc)
-{
-	int ret;
-	int chunks;
-	struct output_file *out;
-
-	chunks = sparse_count_chunks(s);
-	out = output_file_open_fd(fd, s->block_size, s->len, gz, sparse, chunks, crc);
-
-	if (!out)
-		return -ENOMEM;
-
-	ret = write_all_blocks(s, out);
-
-	output_file_close(out);
-
-	return ret;
-}
-
-int sparse_file_callback(struct sparse_file *s, bool sparse, bool crc,
-		int (*write)(void *priv, const void *data, size_t len), void *priv)
-{
-	int ret;
-	int chunks;
-	struct output_file *out;
-
-	chunks = sparse_count_chunks(s);
-	out = output_file_open_callback(write, priv, s->block_size, s->len, false,
-			sparse, chunks, crc);
-
-	if (!out)
-		return -ENOMEM;
-
-	ret = write_all_blocks(s, out);
-
-	output_file_close(out);
-
-	return ret;
-}
-
-struct chunk_data {
-	void		*priv;
-	unsigned int	block;
-	unsigned int	nr_blocks;
-	int (*write)(void *priv, const void *data, size_t len,
-		     unsigned int block, unsigned int nr_blocks);
-};
-
-static int foreach_chunk_write(void *priv, const void *data, size_t len)
-{
-	struct chunk_data *chk = priv;
-
-	return chk->write(chk->priv, data, len, chk->block, chk->nr_blocks);
-}
-
-int sparse_file_foreach_chunk(struct sparse_file *s, bool sparse, bool crc,
-	int (*write)(void *priv, const void *data, size_t len, unsigned int block,
-		     unsigned int nr_blocks),
-	void *priv)
-{
-	int ret;
-	int chunks;
-	struct chunk_data chk;
-	struct output_file *out;
-	struct backed_block *bb;
-
-	chk.priv = priv;
-	chk.write = write;
-	chk.block = chk.nr_blocks = 0;
-	chunks = sparse_count_chunks(s);
-	out = output_file_open_callback(foreach_chunk_write, &chk,
-					s->block_size, s->len, false, sparse,
-					chunks, crc);
-
-	if (!out)
-		return -ENOMEM;
-
-	for (bb = backed_block_iter_new(s->backed_block_list); bb;
-			bb = backed_block_iter_next(bb)) {
-		chk.block = backed_block_block(bb);
-		chk.nr_blocks = (backed_block_len(bb) - 1) / s->block_size + 1;
-		ret = sparse_file_write_block(out, bb);
-		if (ret)
-			return ret;
-	}
-
-	output_file_close(out);
-
-	return ret;
-}
-
-static int out_counter_write(void *priv, const void *data __unused, size_t len)
-{
-	int64_t *count = priv;
-	*count += len;
-	return 0;
-}
-
-int64_t sparse_file_len(struct sparse_file *s, bool sparse, bool crc)
-{
-	int ret;
-	int chunks = sparse_count_chunks(s);
-	int64_t count = 0;
-	struct output_file *out;
-
-	out = output_file_open_callback(out_counter_write, &count,
-			s->block_size, s->len, false, sparse, chunks, crc);
-	if (!out) {
-		return -1;
-	}
-
-	ret = write_all_blocks(s, out);
-
-	output_file_close(out);
-
-	if (ret < 0) {
-		return -1;
-	}
-
-	return count;
-}
-
-unsigned int sparse_file_block_size(struct sparse_file *s)
-{
-	return s->block_size;
-}
-
-static struct backed_block *move_chunks_up_to_len(struct sparse_file *from,
-		struct sparse_file *to, unsigned int len)
-{
-	int64_t count = 0;
-	struct output_file *out_counter;
-	struct backed_block *last_bb = NULL;
-	struct backed_block *bb;
-	struct backed_block *start;
-	unsigned int last_block = 0;
-	int64_t file_len = 0;
-	int ret;
-
-	/*
-	 * overhead is sparse file header, the potential end skip
-	 * chunk and crc chunk.
-	 */
-	int overhead = sizeof(sparse_header_t) + 2 * sizeof(chunk_header_t) +
-			sizeof(uint32_t);
-	len -= overhead;
-
-	start = backed_block_iter_new(from->backed_block_list);
-	out_counter = output_file_open_callback(out_counter_write, &count,
-			to->block_size, to->len, false, true, 0, false);
-	if (!out_counter) {
-		return NULL;
-	}
-
-	for (bb = start; bb; bb = backed_block_iter_next(bb)) {
-		count = 0;
-		if (backed_block_block(bb) > last_block)
-			count += sizeof(chunk_header_t);
-		last_block = backed_block_block(bb) +
-				DIV_ROUND_UP(backed_block_len(bb), to->block_size);
-
-		/* will call out_counter_write to update count */
-		ret = sparse_file_write_block(out_counter, bb);
-		if (ret) {
-			bb = NULL;
-			goto out;
-		}
-		if (file_len + count > len) {
-			/*
-			 * If the remaining available size is more than 1/8th of the
-			 * requested size, split the chunk.  Results in sparse files that
-			 * are at least 7/8ths of the requested size
-			 */
-			file_len += sizeof(chunk_header_t);
-			if (!last_bb || (len - file_len > (len / 8))) {
-				backed_block_split(from->backed_block_list, bb, len - file_len);
-				last_bb = bb;
-			}
-			goto move;
-		}
-		file_len += count;
-		last_bb = bb;
-	}
-
-move:
-	backed_block_list_move(from->backed_block_list,
-		to->backed_block_list, start, last_bb);
-
-out:
-	output_file_close(out_counter);
-
-	return bb;
-}
-
-int sparse_file_resparse(struct sparse_file *in_s, unsigned int max_len,
-		struct sparse_file **out_s, int out_s_count)
-{
-	struct backed_block *bb;
-	struct sparse_file *s;
-	struct sparse_file *tmp;
-	int c = 0;
-
-	tmp = sparse_file_new(in_s->block_size, in_s->len);
-	if (!tmp) {
-		return -ENOMEM;
-	}
-
-	do {
-		s = sparse_file_new(in_s->block_size, in_s->len);
-
-		bb = move_chunks_up_to_len(in_s, s, max_len);
-
-		if (c < out_s_count) {
-			out_s[c] = s;
-		} else {
-			backed_block_list_move(s->backed_block_list, tmp->backed_block_list,
-					NULL, NULL);
-			sparse_file_destroy(s);
-		}
-		c++;
-	} while (bb);
-
-	backed_block_list_move(tmp->backed_block_list, in_s->backed_block_list,
-			NULL, NULL);
-
-	sparse_file_destroy(tmp);
-
-	return c;
-}
-
-void sparse_file_verbose(struct sparse_file *s)
-{
-	s->verbose = true;
-}
diff --git a/libsparse/sparse.cpp b/libsparse/sparse.cpp
new file mode 100644
index 0000000..6ff97b6
--- /dev/null
+++ b/libsparse/sparse.cpp
@@ -0,0 +1,348 @@
+/*
+ * Copyright (C) 2012 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <assert.h>
+#include <stdlib.h>
+
+#include <sparse/sparse.h>
+
+#include "defs.h"
+#include "sparse_file.h"
+
+#include "backed_block.h"
+#include "output_file.h"
+#include "sparse_defs.h"
+#include "sparse_format.h"
+
+struct sparse_file* sparse_file_new(unsigned int block_size, int64_t len) {
+  struct sparse_file* s = reinterpret_cast<sparse_file*>(calloc(sizeof(struct sparse_file), 1));
+  if (!s) {
+    return NULL;
+  }
+
+  s->backed_block_list = backed_block_list_new(block_size);
+  if (!s->backed_block_list) {
+    free(s);
+    return NULL;
+  }
+
+  s->block_size = block_size;
+  s->len = len;
+
+  return s;
+}
+
+void sparse_file_destroy(struct sparse_file* s) {
+  backed_block_list_destroy(s->backed_block_list);
+  free(s);
+}
+
+int sparse_file_add_data(struct sparse_file* s, void* data, unsigned int len, unsigned int block) {
+  return backed_block_add_data(s->backed_block_list, data, len, block);
+}
+
+int sparse_file_add_fill(struct sparse_file* s, uint32_t fill_val, unsigned int len,
+                         unsigned int block) {
+  return backed_block_add_fill(s->backed_block_list, fill_val, len, block);
+}
+
+int sparse_file_add_file(struct sparse_file* s, const char* filename, int64_t file_offset,
+                         unsigned int len, unsigned int block) {
+  return backed_block_add_file(s->backed_block_list, filename, file_offset, len, block);
+}
+
+int sparse_file_add_fd(struct sparse_file* s, int fd, int64_t file_offset, unsigned int len,
+                       unsigned int block) {
+  return backed_block_add_fd(s->backed_block_list, fd, file_offset, len, block);
+}
+unsigned int sparse_count_chunks(struct sparse_file* s) {
+  struct backed_block* bb;
+  unsigned int last_block = 0;
+  unsigned int chunks = 0;
+
+  for (bb = backed_block_iter_new(s->backed_block_list); bb; bb = backed_block_iter_next(bb)) {
+    if (backed_block_block(bb) > last_block) {
+      /* If there is a gap between chunks, add a skip chunk */
+      chunks++;
+    }
+    chunks++;
+    last_block = backed_block_block(bb) + DIV_ROUND_UP(backed_block_len(bb), s->block_size);
+  }
+  if (last_block < DIV_ROUND_UP(s->len, s->block_size)) {
+    chunks++;
+  }
+
+  return chunks;
+}
+
+static int sparse_file_write_block(struct output_file* out, struct backed_block* bb) {
+  int ret = -EINVAL;
+
+  switch (backed_block_type(bb)) {
+    case BACKED_BLOCK_DATA:
+      ret = write_data_chunk(out, backed_block_len(bb), backed_block_data(bb));
+      break;
+    case BACKED_BLOCK_FILE:
+      ret = write_file_chunk(out, backed_block_len(bb), backed_block_filename(bb),
+                             backed_block_file_offset(bb));
+      break;
+    case BACKED_BLOCK_FD:
+      ret = write_fd_chunk(out, backed_block_len(bb), backed_block_fd(bb),
+                           backed_block_file_offset(bb));
+      break;
+    case BACKED_BLOCK_FILL:
+      ret = write_fill_chunk(out, backed_block_len(bb), backed_block_fill_val(bb));
+      break;
+  }
+
+  return ret;
+}
+
+static int write_all_blocks(struct sparse_file* s, struct output_file* out) {
+  struct backed_block* bb;
+  unsigned int last_block = 0;
+  int64_t pad;
+  int ret = 0;
+
+  for (bb = backed_block_iter_new(s->backed_block_list); bb; bb = backed_block_iter_next(bb)) {
+    if (backed_block_block(bb) > last_block) {
+      unsigned int blocks = backed_block_block(bb) - last_block;
+      write_skip_chunk(out, (int64_t)blocks * s->block_size);
+    }
+    ret = sparse_file_write_block(out, bb);
+    if (ret) return ret;
+    last_block = backed_block_block(bb) + DIV_ROUND_UP(backed_block_len(bb), s->block_size);
+  }
+
+  pad = s->len - (int64_t)last_block * s->block_size;
+  assert(pad >= 0);
+  if (pad > 0) {
+    write_skip_chunk(out, pad);
+  }
+
+  return 0;
+}
+
+int sparse_file_write(struct sparse_file* s, int fd, bool gz, bool sparse, bool crc) {
+  int ret;
+  int chunks;
+  struct output_file* out;
+
+  chunks = sparse_count_chunks(s);
+  out = output_file_open_fd(fd, s->block_size, s->len, gz, sparse, chunks, crc);
+
+  if (!out) return -ENOMEM;
+
+  ret = write_all_blocks(s, out);
+
+  output_file_close(out);
+
+  return ret;
+}
+
+int sparse_file_callback(struct sparse_file* s, bool sparse, bool crc,
+                         int (*write)(void* priv, const void* data, size_t len), void* priv) {
+  int ret;
+  int chunks;
+  struct output_file* out;
+
+  chunks = sparse_count_chunks(s);
+  out = output_file_open_callback(write, priv, s->block_size, s->len, false, sparse, chunks, crc);
+
+  if (!out) return -ENOMEM;
+
+  ret = write_all_blocks(s, out);
+
+  output_file_close(out);
+
+  return ret;
+}
+
+struct chunk_data {
+  void* priv;
+  unsigned int block;
+  unsigned int nr_blocks;
+  int (*write)(void* priv, const void* data, size_t len, unsigned int block, unsigned int nr_blocks);
+};
+
+static int foreach_chunk_write(void* priv, const void* data, size_t len) {
+  struct chunk_data* chk = reinterpret_cast<chunk_data*>(priv);
+
+  return chk->write(chk->priv, data, len, chk->block, chk->nr_blocks);
+}
+
+int sparse_file_foreach_chunk(struct sparse_file* s, bool sparse, bool crc,
+                              int (*write)(void* priv, const void* data, size_t len,
+                                           unsigned int block, unsigned int nr_blocks),
+                              void* priv) {
+  int ret;
+  int chunks;
+  struct chunk_data chk;
+  struct output_file* out;
+  struct backed_block* bb;
+
+  chk.priv = priv;
+  chk.write = write;
+  chk.block = chk.nr_blocks = 0;
+  chunks = sparse_count_chunks(s);
+  out = output_file_open_callback(foreach_chunk_write, &chk, s->block_size, s->len, false, sparse,
+                                  chunks, crc);
+
+  if (!out) return -ENOMEM;
+
+  for (bb = backed_block_iter_new(s->backed_block_list); bb; bb = backed_block_iter_next(bb)) {
+    chk.block = backed_block_block(bb);
+    chk.nr_blocks = (backed_block_len(bb) - 1) / s->block_size + 1;
+    ret = sparse_file_write_block(out, bb);
+    if (ret) return ret;
+  }
+
+  output_file_close(out);
+
+  return ret;
+}
+
+static int out_counter_write(void* priv, const void* data __unused, size_t len) {
+  int64_t* count = reinterpret_cast<int64_t*>(priv);
+  *count += len;
+  return 0;
+}
+
+int64_t sparse_file_len(struct sparse_file* s, bool sparse, bool crc) {
+  int ret;
+  int chunks = sparse_count_chunks(s);
+  int64_t count = 0;
+  struct output_file* out;
+
+  out = output_file_open_callback(out_counter_write, &count, s->block_size, s->len, false, sparse,
+                                  chunks, crc);
+  if (!out) {
+    return -1;
+  }
+
+  ret = write_all_blocks(s, out);
+
+  output_file_close(out);
+
+  if (ret < 0) {
+    return -1;
+  }
+
+  return count;
+}
+
+unsigned int sparse_file_block_size(struct sparse_file* s) {
+  return s->block_size;
+}
+
+static struct backed_block* move_chunks_up_to_len(struct sparse_file* from, struct sparse_file* to,
+                                                  unsigned int len) {
+  int64_t count = 0;
+  struct output_file* out_counter;
+  struct backed_block* last_bb = NULL;
+  struct backed_block* bb;
+  struct backed_block* start;
+  unsigned int last_block = 0;
+  int64_t file_len = 0;
+  int ret;
+
+  /*
+   * overhead is sparse file header, the potential end skip
+   * chunk and crc chunk.
+   */
+  int overhead = sizeof(sparse_header_t) + 2 * sizeof(chunk_header_t) + sizeof(uint32_t);
+  len -= overhead;
+
+  start = backed_block_iter_new(from->backed_block_list);
+  out_counter = output_file_open_callback(out_counter_write, &count, to->block_size, to->len, false,
+                                          true, 0, false);
+  if (!out_counter) {
+    return NULL;
+  }
+
+  for (bb = start; bb; bb = backed_block_iter_next(bb)) {
+    count = 0;
+    if (backed_block_block(bb) > last_block) count += sizeof(chunk_header_t);
+    last_block = backed_block_block(bb) + DIV_ROUND_UP(backed_block_len(bb), to->block_size);
+
+    /* will call out_counter_write to update count */
+    ret = sparse_file_write_block(out_counter, bb);
+    if (ret) {
+      bb = NULL;
+      goto out;
+    }
+    if (file_len + count > len) {
+      /*
+       * If the remaining available size is more than 1/8th of the
+       * requested size, split the chunk.  Results in sparse files that
+       * are at least 7/8ths of the requested size
+       */
+      file_len += sizeof(chunk_header_t);
+      if (!last_bb || (len - file_len > (len / 8))) {
+        backed_block_split(from->backed_block_list, bb, len - file_len);
+        last_bb = bb;
+      }
+      goto move;
+    }
+    file_len += count;
+    last_bb = bb;
+  }
+
+move:
+  backed_block_list_move(from->backed_block_list, to->backed_block_list, start, last_bb);
+
+out:
+  output_file_close(out_counter);
+
+  return bb;
+}
+
+int sparse_file_resparse(struct sparse_file* in_s, unsigned int max_len, struct sparse_file** out_s,
+                         int out_s_count) {
+  struct backed_block* bb;
+  struct sparse_file* s;
+  struct sparse_file* tmp;
+  int c = 0;
+
+  tmp = sparse_file_new(in_s->block_size, in_s->len);
+  if (!tmp) {
+    return -ENOMEM;
+  }
+
+  do {
+    s = sparse_file_new(in_s->block_size, in_s->len);
+
+    bb = move_chunks_up_to_len(in_s, s, max_len);
+
+    if (c < out_s_count) {
+      out_s[c] = s;
+    } else {
+      backed_block_list_move(s->backed_block_list, tmp->backed_block_list, NULL, NULL);
+      sparse_file_destroy(s);
+    }
+    c++;
+  } while (bb);
+
+  backed_block_list_move(tmp->backed_block_list, in_s->backed_block_list, NULL, NULL);
+
+  sparse_file_destroy(tmp);
+
+  return c;
+}
+
+void sparse_file_verbose(struct sparse_file* s) {
+  s->verbose = true;
+}
diff --git a/libsparse/sparse_crc32.c b/libsparse/sparse_crc32.c
deleted file mode 100644
index 38bfe4a..0000000
--- a/libsparse/sparse_crc32.c
+++ /dev/null
@@ -1,111 +0,0 @@
-/*-
- *  COPYRIGHT (C) 1986 Gary S. Brown.  You may use this program, or
- *  code or tables extracted from it, as desired without restriction.
- */
-
-/*
- *  First, the polynomial itself and its table of feedback terms.  The
- *  polynomial is
- *  X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0
- *
- *  Note that we take it "backwards" and put the highest-order term in
- *  the lowest-order bit.  The X^32 term is "implied"; the LSB is the
- *  X^31 term, etc.  The X^0 term (usually shown as "+1") results in
- *  the MSB being 1
- *
- *  Note that the usual hardware shift register implementation, which
- *  is what we're using (we're merely optimizing it by doing eight-bit
- *  chunks at a time) shifts bits into the lowest-order term.  In our
- *  implementation, that means shifting towards the right.  Why do we
- *  do it this way?  Because the calculated CRC must be transmitted in
- *  order from highest-order term to lowest-order term.  UARTs transmit
- *  characters in order from LSB to MSB.  By storing the CRC this way
- *  we hand it to the UART in the order low-byte to high-byte; the UART
- *  sends each low-bit to hight-bit; and the result is transmission bit
- *  by bit from highest- to lowest-order term without requiring any bit
- *  shuffling on our part.  Reception works similarly
- *
- *  The feedback terms table consists of 256, 32-bit entries.  Notes
- *
- *      The table can be generated at runtime if desired; code to do so
- *      is shown later.  It might not be obvious, but the feedback
- *      terms simply represent the results of eight shift/xor opera
- *      tions for all combinations of data and CRC register values
- *
- *      The values must be right-shifted by eight bits by the "updcrc
- *      logic; the shift must be unsigned (bring in zeroes).  On some
- *      hardware you could probably optimize the shift in assembler by
- *      using byte-swap instructions
- *      polynomial $edb88320
- *
- *
- * CRC32 code derived from work by Gary S. Brown.
- */
-
-/* Code taken from FreeBSD 8 */
-#include <stdint.h>
-
-static uint32_t crc32_tab[] = {
-        0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
-        0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
-        0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
-        0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
-        0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
-        0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
-        0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
-        0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
-        0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
-        0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
-        0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
-        0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
-        0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
-        0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
-        0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
-        0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
-        0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
-        0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
-        0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
-        0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
-        0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
-        0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
-        0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
-        0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
-        0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
-        0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
-        0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
-        0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
-        0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
-        0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
-        0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
-        0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
-        0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
-        0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
-        0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
-        0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
-        0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
-        0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
-        0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
-        0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
-        0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
-        0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
-        0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
-};
-
-/*
- * A function that calculates the CRC-32 based on the table above is
- * given below for documentation purposes. An equivalent implementation
- * of this function that's actually used in the kernel can be found
- * in sys/libkern.h, where it can be inlined.
- */
-
-uint32_t sparse_crc32(uint32_t crc_in, const void *buf, int size)
-{
-        const uint8_t *p = buf;
-        uint32_t crc;
-
-        crc = crc_in ^ ~0U;
-        while (size--)
-                crc = crc32_tab[(crc ^ *p++) & 0xFF] ^ (crc >> 8);
-        return crc ^ ~0U;
-}
-
diff --git a/libsparse/sparse_crc32.cpp b/libsparse/sparse_crc32.cpp
new file mode 100644
index 0000000..267322c
--- /dev/null
+++ b/libsparse/sparse_crc32.cpp
@@ -0,0 +1,97 @@
+/*-
+ *  COPYRIGHT (C) 1986 Gary S. Brown.  You may use this program, or
+ *  code or tables extracted from it, as desired without restriction.
+ */
+
+/*
+ *  First, the polynomial itself and its table of feedback terms.  The
+ *  polynomial is
+ *  X^32+X^26+X^23+X^22+X^16+X^12+X^11+X^10+X^8+X^7+X^5+X^4+X^2+X^1+X^0
+ *
+ *  Note that we take it "backwards" and put the highest-order term in
+ *  the lowest-order bit.  The X^32 term is "implied"; the LSB is the
+ *  X^31 term, etc.  The X^0 term (usually shown as "+1") results in
+ *  the MSB being 1
+ *
+ *  Note that the usual hardware shift register implementation, which
+ *  is what we're using (we're merely optimizing it by doing eight-bit
+ *  chunks at a time) shifts bits into the lowest-order term.  In our
+ *  implementation, that means shifting towards the right.  Why do we
+ *  do it this way?  Because the calculated CRC must be transmitted in
+ *  order from highest-order term to lowest-order term.  UARTs transmit
+ *  characters in order from LSB to MSB.  By storing the CRC this way
+ *  we hand it to the UART in the order low-byte to high-byte; the UART
+ *  sends each low-bit to hight-bit; and the result is transmission bit
+ *  by bit from highest- to lowest-order term without requiring any bit
+ *  shuffling on our part.  Reception works similarly
+ *
+ *  The feedback terms table consists of 256, 32-bit entries.  Notes
+ *
+ *      The table can be generated at runtime if desired; code to do so
+ *      is shown later.  It might not be obvious, but the feedback
+ *      terms simply represent the results of eight shift/xor opera
+ *      tions for all combinations of data and CRC register values
+ *
+ *      The values must be right-shifted by eight bits by the "updcrc
+ *      logic; the shift must be unsigned (bring in zeroes).  On some
+ *      hardware you could probably optimize the shift in assembler by
+ *      using byte-swap instructions
+ *      polynomial $edb88320
+ *
+ *
+ * CRC32 code derived from work by Gary S. Brown.
+ */
+
+/* Code taken from FreeBSD 8 */
+#include <stdint.h>
+#include <stdio.h>
+
+static uint32_t crc32_tab[] = {
+    0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f, 0xe963a535, 0x9e6495a3,
+    0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988, 0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91,
+    0x1db71064, 0x6ab020f2, 0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
+    0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9, 0xfa0f3d63, 0x8d080df5,
+    0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172, 0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b,
+    0x35b5a8fa, 0x42b2986c, 0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
+    0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423, 0xcfba9599, 0xb8bda50f,
+    0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924, 0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d,
+    0x76dc4190, 0x01db7106, 0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
+    0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d, 0x91646c97, 0xe6635c01,
+    0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e, 0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457,
+    0x65b0d9c6, 0x12b7e950, 0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
+    0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7, 0xa4d1c46d, 0xd3d6f4fb,
+    0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0, 0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9,
+    0x5005713c, 0x270241aa, 0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
+    0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81, 0xb7bd5c3b, 0xc0ba6cad,
+    0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a, 0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683,
+    0xe3630b12, 0x94643b84, 0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
+    0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb, 0x196c3671, 0x6e6b06e7,
+    0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc, 0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5,
+    0xd6d6a3e8, 0xa1d1937e, 0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
+    0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55, 0x316e8eef, 0x4669be79,
+    0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236, 0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f,
+    0xc5ba3bbe, 0xb2bd0b28, 0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
+    0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f, 0x72076785, 0x05005713,
+    0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38, 0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21,
+    0x86d3d2d4, 0xf1d4e242, 0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
+    0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69, 0x616bffd3, 0x166ccf45,
+    0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2, 0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db,
+    0xaed16a4a, 0xd9d65adc, 0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
+    0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693, 0x54de5729, 0x23d967bf,
+    0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94, 0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d};
+
+/*
+ * A function that calculates the CRC-32 based on the table above is
+ * given below for documentation purposes. An equivalent implementation
+ * of this function that's actually used in the kernel can be found
+ * in sys/libkern.h, where it can be inlined.
+ */
+
+uint32_t sparse_crc32(uint32_t crc_in, const void* buf, size_t size) {
+  const uint8_t* p = reinterpret_cast<const uint8_t*>(buf);
+  uint32_t crc;
+
+  crc = crc_in ^ ~0U;
+  while (size--) crc = crc32_tab[(crc ^ *p++) & 0xFF] ^ (crc >> 8);
+  return crc ^ ~0U;
+}
diff --git a/libsparse/sparse_crc32.h b/libsparse/sparse_crc32.h
index 50cd9e9..2702c4f 100644
--- a/libsparse/sparse_crc32.h
+++ b/libsparse/sparse_crc32.h
@@ -19,14 +19,6 @@
 
 #include <stdint.h>
 
-#ifdef __cplusplus
-extern "C" {
-#endif
-
-uint32_t sparse_crc32(uint32_t crc, const void *buf, size_t size);
-
-#ifdef __cplusplus
-}
-#endif
+uint32_t sparse_crc32(uint32_t crc, const void* buf, size_t size);
 
 #endif
diff --git a/libsparse/sparse_defs.h b/libsparse/sparse_defs.h
index b99cfd5..9137805 100644
--- a/libsparse/sparse_defs.h
+++ b/libsparse/sparse_defs.h
@@ -39,11 +39,14 @@
 typedef unsigned short int u16;
 typedef unsigned char u8;
 
-#define DIV_ROUND_UP(x, y) (((x) + (y) - 1)/(y))
-#define ALIGN(x, y) ((y) * DIV_ROUND_UP((x), (y)))
+#define DIV_ROUND_UP(x, y) (((x) + (y)-1) / (y))
+#define ALIGN(x, y) ((y)*DIV_ROUND_UP((x), (y)))
 #define ALIGN_DOWN(x, y) ((y) * ((x) / (y)))
 
-#define error(fmt, args...) do { fprintf(stderr, "error: %s: " fmt "\n", __func__, ## args); } while (0)
+#define error(fmt, args...)                                    \
+  do {                                                         \
+    fprintf(stderr, "error: %s: " fmt "\n", __func__, ##args); \
+  } while (0)
 #define error_errno(s, args...) error(s ": %s", ##args, strerror(errno))
 
 #endif
diff --git a/libsparse/sparse_err.c b/libsparse/sparse_err.cpp
similarity index 73%
rename from libsparse/sparse_err.c
rename to libsparse/sparse_err.cpp
index 0f392ad..6886d31 100644
--- a/libsparse/sparse_err.c
+++ b/libsparse/sparse_err.cpp
@@ -20,14 +20,13 @@
 #include <stdio.h>
 #include <unistd.h>
 
-void sparse_default_print(const char *fmt, ...)
-{
-	va_list argp;
+void sparse_default_print(const char* fmt, ...) {
+  va_list argp;
 
-	va_start(argp, fmt);
-	vfprintf(stderr, fmt, argp);
-	va_end(argp);
+  va_start(argp, fmt);
+  vfprintf(stderr, fmt, argp);
+  va_end(argp);
 }
 
-void (*sparse_print_error)(const char *fmt, ...) = sparse_default_print;
-void (*sparse_print_verbose)(const char *fmt, ...) = sparse_default_print;
+void (*sparse_print_error)(const char* fmt, ...) = sparse_default_print;
+void (*sparse_print_verbose)(const char* fmt, ...) = sparse_default_print;
diff --git a/libsparse/sparse_file.h b/libsparse/sparse_file.h
index 763f43f..e565f63 100644
--- a/libsparse/sparse_file.h
+++ b/libsparse/sparse_file.h
@@ -24,12 +24,12 @@
 #include <sparse/sparse.h>
 
 struct sparse_file {
-	unsigned int block_size;
-	int64_t len;
-	bool verbose;
+  unsigned int block_size;
+  int64_t len;
+  bool verbose;
 
-	struct backed_block_list *backed_block_list;
-	struct output_file *out;
+  struct backed_block_list* backed_block_list;
+  struct output_file* out;
 };
 
 #ifdef __cplusplus
diff --git a/libsparse/sparse_format.h b/libsparse/sparse_format.h
index 779e038..a8a721e 100644
--- a/libsparse/sparse_format.h
+++ b/libsparse/sparse_format.h
@@ -23,31 +23,31 @@
 #endif
 
 typedef struct sparse_header {
-  __le32	magic;		/* 0xed26ff3a */
-  __le16	major_version;	/* (0x1) - reject images with higher major versions */
-  __le16	minor_version;	/* (0x0) - allow images with higer minor versions */
-  __le16	file_hdr_sz;	/* 28 bytes for first revision of the file format */
-  __le16	chunk_hdr_sz;	/* 12 bytes for first revision of the file format */
-  __le32	blk_sz;		/* block size in bytes, must be a multiple of 4 (4096) */
-  __le32	total_blks;	/* total blocks in the non-sparse output image */
-  __le32	total_chunks;	/* total chunks in the sparse input image */
-  __le32	image_checksum; /* CRC32 checksum of the original data, counting "don't care" */
-				/* as 0. Standard 802.3 polynomial, use a Public Domain */
-				/* table implementation */
+  __le32 magic;          /* 0xed26ff3a */
+  __le16 major_version;  /* (0x1) - reject images with higher major versions */
+  __le16 minor_version;  /* (0x0) - allow images with higer minor versions */
+  __le16 file_hdr_sz;    /* 28 bytes for first revision of the file format */
+  __le16 chunk_hdr_sz;   /* 12 bytes for first revision of the file format */
+  __le32 blk_sz;         /* block size in bytes, must be a multiple of 4 (4096) */
+  __le32 total_blks;     /* total blocks in the non-sparse output image */
+  __le32 total_chunks;   /* total chunks in the sparse input image */
+  __le32 image_checksum; /* CRC32 checksum of the original data, counting "don't care" */
+                         /* as 0. Standard 802.3 polynomial, use a Public Domain */
+                         /* table implementation */
 } sparse_header_t;
 
-#define SPARSE_HEADER_MAGIC	0xed26ff3a
+#define SPARSE_HEADER_MAGIC 0xed26ff3a
 
-#define CHUNK_TYPE_RAW		0xCAC1
-#define CHUNK_TYPE_FILL		0xCAC2
-#define CHUNK_TYPE_DONT_CARE	0xCAC3
-#define CHUNK_TYPE_CRC32    0xCAC4
+#define CHUNK_TYPE_RAW 0xCAC1
+#define CHUNK_TYPE_FILL 0xCAC2
+#define CHUNK_TYPE_DONT_CARE 0xCAC3
+#define CHUNK_TYPE_CRC32 0xCAC4
 
 typedef struct chunk_header {
-  __le16	chunk_type;	/* 0xCAC1 -> raw; 0xCAC2 -> fill; 0xCAC3 -> don't care */
-  __le16	reserved1;
-  __le32	chunk_sz;	/* in blocks in output image */
-  __le32	total_sz;	/* in bytes of chunk input file including chunk header and data */
+  __le16 chunk_type; /* 0xCAC1 -> raw; 0xCAC2 -> fill; 0xCAC3 -> don't care */
+  __le16 reserved1;
+  __le32 chunk_sz; /* in blocks in output image */
+  __le32 total_sz; /* in bytes of chunk input file including chunk header and data */
 } chunk_header_t;
 
 /* Following a Raw or Fill or CRC32 chunk is data.
diff --git a/libsparse/sparse_read.cpp b/libsparse/sparse_read.cpp
index 4379635..56e2c9a 100644
--- a/libsparse/sparse_read.cpp
+++ b/libsparse/sparse_read.cpp
@@ -17,16 +17,16 @@
 #define _FILE_OFFSET_BITS 64
 #define _LARGEFILE64_SOURCE 1
 
-#include <algorithm>
-#include <inttypes.h>
 #include <fcntl.h>
+#include <inttypes.h>
 #include <stdarg.h>
 #include <stdint.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
-#include <string>
 #include <unistd.h>
+#include <algorithm>
+#include <string>
 
 #include <sparse/sparse.h>
 
@@ -37,447 +37,541 @@
 #include "sparse_file.h"
 #include "sparse_format.h"
 
-
 #if defined(__APPLE__) && defined(__MACH__)
 #define lseek64 lseek
 #define off64_t off_t
 #endif
 
 #define SPARSE_HEADER_MAJOR_VER 1
-#define SPARSE_HEADER_LEN       (sizeof(sparse_header_t))
+#define SPARSE_HEADER_LEN (sizeof(sparse_header_t))
 #define CHUNK_HEADER_LEN (sizeof(chunk_header_t))
 
 static constexpr int64_t COPY_BUF_SIZE = 1024 * 1024;
-static char *copybuf;
+static char* copybuf;
 
-static std::string ErrorString(int err)
-{
-	if (err == -EOVERFLOW) return "EOF while reading file";
-	if (err == -EINVAL) return "Invalid sparse file format";
-	if (err == -ENOMEM) return "Failed allocation while reading file";
-	return android::base::StringPrintf("Unknown error %d", err);
+static std::string ErrorString(int err) {
+  if (err == -EOVERFLOW) return "EOF while reading file";
+  if (err == -EINVAL) return "Invalid sparse file format";
+  if (err == -ENOMEM) return "Failed allocation while reading file";
+  return android::base::StringPrintf("Unknown error %d", err);
 }
 
-static void verbose_error(bool verbose, int err, const char *fmt, ...)
-{
-	if (!verbose) return;
+class SparseFileSource {
+ public:
+  /* Seeks the source ahead by the given offset. */
+  virtual void Seek(int64_t offset) = 0;
 
-	std::string msg = ErrorString(err);
-	if (fmt) {
-		msg += " at ";
-		va_list argp;
-		va_start(argp, fmt);
-		android::base::StringAppendV(&msg, fmt, argp);
-		va_end(argp);
-	}
-	sparse_print_verbose("%s\n", msg.c_str());
+  /* Return the current offset. */
+  virtual int64_t GetOffset() = 0;
+
+  /* Set the current offset. Return 0 if successful. */
+  virtual int SetOffset(int64_t offset) = 0;
+
+  /* Adds the given length from the current offset of the source to the file at the given block.
+   * Return 0 if successful. */
+  virtual int AddToSparseFile(struct sparse_file* s, int64_t len, unsigned int block) = 0;
+
+  /* Get data of fixed size from the current offset and seek len bytes. Return 0 if successful. */
+  virtual int ReadValue(void* ptr, int len) = 0;
+
+  /* Find the crc32 of the next len bytes and seek ahead len bytes. Return 0 if successful. */
+  virtual int GetCrc32(uint32_t* crc32, int64_t len) = 0;
+
+  virtual ~SparseFileSource(){};
+};
+
+class SparseFileFdSource : public SparseFileSource {
+ private:
+  int fd;
+
+ public:
+  SparseFileFdSource(int fd) : fd(fd) {}
+  ~SparseFileFdSource() override {}
+
+  void Seek(int64_t off) override { lseek64(fd, off, SEEK_CUR); }
+
+  int64_t GetOffset() override { return lseek64(fd, 0, SEEK_CUR); }
+
+  int SetOffset(int64_t offset) override {
+    return lseek64(fd, offset, SEEK_SET) == offset ? 0 : -errno;
+  }
+
+  int AddToSparseFile(struct sparse_file* s, int64_t len, unsigned int block) override {
+    return sparse_file_add_fd(s, fd, GetOffset(), len, block);
+  }
+
+  int ReadValue(void* ptr, int len) override { return read_all(fd, ptr, len); }
+
+  int GetCrc32(uint32_t* crc32, int64_t len) override {
+    int chunk;
+    int ret;
+    while (len) {
+      chunk = std::min(len, COPY_BUF_SIZE);
+      ret = read_all(fd, copybuf, chunk);
+      if (ret < 0) {
+        return ret;
+      }
+      *crc32 = sparse_crc32(*crc32, copybuf, chunk);
+      len -= chunk;
+    }
+    return 0;
+  }
+};
+
+class SparseFileBufSource : public SparseFileSource {
+ private:
+  char* buf;
+  int64_t offset;
+
+ public:
+  SparseFileBufSource(char* buf) : buf(buf), offset(0) {}
+  ~SparseFileBufSource() override {}
+
+  void Seek(int64_t off) override {
+    buf += off;
+    offset += off;
+  }
+
+  int64_t GetOffset() override { return offset; }
+
+  int SetOffset(int64_t off) override {
+    buf += off - offset;
+    offset = off;
+    return 0;
+  }
+
+  int AddToSparseFile(struct sparse_file* s, int64_t len, unsigned int block) override {
+    return sparse_file_add_data(s, buf, len, block);
+  }
+
+  int ReadValue(void* ptr, int len) override {
+    memcpy(ptr, buf, len);
+    Seek(len);
+    return 0;
+  }
+
+  int GetCrc32(uint32_t* crc32, int64_t len) override {
+    *crc32 = sparse_crc32(*crc32, buf, len);
+    Seek(len);
+    return 0;
+  }
+};
+
+static void verbose_error(bool verbose, int err, const char* fmt, ...) {
+  if (!verbose) return;
+
+  std::string msg = ErrorString(err);
+  if (fmt) {
+    msg += " at ";
+    va_list argp;
+    va_start(argp, fmt);
+    android::base::StringAppendV(&msg, fmt, argp);
+    va_end(argp);
+  }
+  sparse_print_verbose("%s\n", msg.c_str());
 }
 
-static int process_raw_chunk(struct sparse_file *s, unsigned int chunk_size,
-		int fd, int64_t offset, unsigned int blocks, unsigned int block,
-		uint32_t *crc32)
-{
-	int ret;
-	int chunk;
-	int64_t len = blocks * s->block_size;
+static int process_raw_chunk(struct sparse_file* s, unsigned int chunk_size,
+                             SparseFileSource* source, unsigned int blocks, unsigned int block,
+                             uint32_t* crc32) {
+  int ret;
+  int64_t len = blocks * s->block_size;
 
-	if (chunk_size % s->block_size != 0) {
-		return -EINVAL;
-	}
+  if (chunk_size % s->block_size != 0) {
+    return -EINVAL;
+  }
 
-	if (chunk_size / s->block_size != blocks) {
-		return -EINVAL;
-	}
+  if (chunk_size / s->block_size != blocks) {
+    return -EINVAL;
+  }
 
-	ret = sparse_file_add_fd(s, fd, offset, len, block);
-	if (ret < 0) {
-		return ret;
-	}
+  ret = source->AddToSparseFile(s, len, block);
+  if (ret < 0) {
+    return ret;
+  }
 
-	if (crc32) {
-		while (len) {
-			chunk = std::min(len, COPY_BUF_SIZE);
-			ret = read_all(fd, copybuf, chunk);
-			if (ret < 0) {
-				return ret;
-			}
-			*crc32 = sparse_crc32(*crc32, copybuf, chunk);
-			len -= chunk;
-		}
-	} else {
-		lseek64(fd, len, SEEK_CUR);
-	}
+  if (crc32) {
+    ret = source->GetCrc32(crc32, len);
+    if (ret < 0) {
+      return ret;
+    }
+  } else {
+    source->Seek(len);
+  }
 
-	return 0;
+  return 0;
 }
 
-static int process_fill_chunk(struct sparse_file *s, unsigned int chunk_size,
-		int fd, unsigned int blocks, unsigned int block, uint32_t *crc32)
-{
-	int ret;
-	int chunk;
-	int64_t len = (int64_t)blocks * s->block_size;
-	uint32_t fill_val;
-	uint32_t *fillbuf;
-	unsigned int i;
+static int process_fill_chunk(struct sparse_file* s, unsigned int chunk_size,
+                              SparseFileSource* source, unsigned int blocks, unsigned int block,
+                              uint32_t* crc32) {
+  int ret;
+  int chunk;
+  int64_t len = (int64_t)blocks * s->block_size;
+  uint32_t fill_val;
+  uint32_t* fillbuf;
+  unsigned int i;
 
-	if (chunk_size != sizeof(fill_val)) {
-		return -EINVAL;
-	}
+  if (chunk_size != sizeof(fill_val)) {
+    return -EINVAL;
+  }
 
-	ret = read_all(fd, &fill_val, sizeof(fill_val));
-	if (ret < 0) {
-		return ret;
-	}
+  ret = source->ReadValue(&fill_val, sizeof(fill_val));
+  if (ret < 0) {
+    return ret;
+  }
 
-	ret = sparse_file_add_fill(s, fill_val, len, block);
-	if (ret < 0) {
-		return ret;
-	}
+  ret = sparse_file_add_fill(s, fill_val, len, block);
+  if (ret < 0) {
+    return ret;
+  }
 
-	if (crc32) {
-		/* Fill copy_buf with the fill value */
-		fillbuf = (uint32_t *)copybuf;
-		for (i = 0; i < (COPY_BUF_SIZE / sizeof(fill_val)); i++) {
-			fillbuf[i] = fill_val;
-		}
+  if (crc32) {
+    /* Fill copy_buf with the fill value */
+    fillbuf = (uint32_t*)copybuf;
+    for (i = 0; i < (COPY_BUF_SIZE / sizeof(fill_val)); i++) {
+      fillbuf[i] = fill_val;
+    }
 
-		while (len) {
-			chunk = std::min(len, COPY_BUF_SIZE);
-			*crc32 = sparse_crc32(*crc32, copybuf, chunk);
-			len -= chunk;
-		}
-	}
+    while (len) {
+      chunk = std::min(len, COPY_BUF_SIZE);
+      *crc32 = sparse_crc32(*crc32, copybuf, chunk);
+      len -= chunk;
+    }
+  }
 
-	return 0;
+  return 0;
 }
 
-static int process_skip_chunk(struct sparse_file *s, unsigned int chunk_size,
-		int fd __unused, unsigned int blocks,
-		unsigned int block __unused, uint32_t *crc32)
-{
-	if (chunk_size != 0) {
-		return -EINVAL;
-	}
+static int process_skip_chunk(struct sparse_file* s, unsigned int chunk_size,
+                              SparseFileSource* source __unused, unsigned int blocks,
+                              unsigned int block __unused, uint32_t* crc32) {
+  if (chunk_size != 0) {
+    return -EINVAL;
+  }
 
-	if (crc32) {
-	        int64_t len = (int64_t)blocks * s->block_size;
-		memset(copybuf, 0, COPY_BUF_SIZE);
+  if (crc32) {
+    int64_t len = (int64_t)blocks * s->block_size;
+    memset(copybuf, 0, COPY_BUF_SIZE);
 
-		while (len) {
-			int chunk = std::min(len, COPY_BUF_SIZE);
-			*crc32 = sparse_crc32(*crc32, copybuf, chunk);
-			len -= chunk;
-		}
-	}
+    while (len) {
+      int chunk = std::min(len, COPY_BUF_SIZE);
+      *crc32 = sparse_crc32(*crc32, copybuf, chunk);
+      len -= chunk;
+    }
+  }
 
-	return 0;
+  return 0;
 }
 
-static int process_crc32_chunk(int fd, unsigned int chunk_size, uint32_t *crc32)
-{
-	uint32_t file_crc32;
-	int ret;
+static int process_crc32_chunk(SparseFileSource* source, unsigned int chunk_size, uint32_t* crc32) {
+  uint32_t file_crc32;
 
-	if (chunk_size != sizeof(file_crc32)) {
-		return -EINVAL;
-	}
+  if (chunk_size != sizeof(file_crc32)) {
+    return -EINVAL;
+  }
 
-	ret = read_all(fd, &file_crc32, sizeof(file_crc32));
-	if (ret < 0) {
-		return ret;
-	}
+  int ret = source->ReadValue(&file_crc32, sizeof(file_crc32));
+  if (ret < 0) {
+    return ret;
+  }
 
-	if (crc32 != NULL && file_crc32 != *crc32) {
-		return -EINVAL;
-	}
+  if (crc32 != NULL && file_crc32 != *crc32) {
+    return -EINVAL;
+  }
 
-	return 0;
+  return 0;
 }
 
-static int process_chunk(struct sparse_file *s, int fd, off64_t offset,
-		unsigned int chunk_hdr_sz, chunk_header_t *chunk_header,
-		unsigned int cur_block, uint32_t *crc_ptr)
-{
-	int ret;
-	unsigned int chunk_data_size;
+static int process_chunk(struct sparse_file* s, SparseFileSource* source, unsigned int chunk_hdr_sz,
+                         chunk_header_t* chunk_header, unsigned int cur_block, uint32_t* crc_ptr) {
+  int ret;
+  unsigned int chunk_data_size;
+  int64_t offset = source->GetOffset();
 
-	chunk_data_size = chunk_header->total_sz - chunk_hdr_sz;
+  chunk_data_size = chunk_header->total_sz - chunk_hdr_sz;
 
-	switch (chunk_header->chunk_type) {
-		case CHUNK_TYPE_RAW:
-			ret = process_raw_chunk(s, chunk_data_size, fd, offset,
-					chunk_header->chunk_sz, cur_block, crc_ptr);
-			if (ret < 0) {
-				verbose_error(s->verbose, ret, "data block at %" PRId64, offset);
-				return ret;
-			}
-			return chunk_header->chunk_sz;
-		case CHUNK_TYPE_FILL:
-			ret = process_fill_chunk(s, chunk_data_size, fd,
-					chunk_header->chunk_sz, cur_block, crc_ptr);
-			if (ret < 0) {
-				verbose_error(s->verbose, ret, "fill block at %" PRId64, offset);
-				return ret;
-			}
-			return chunk_header->chunk_sz;
-		case CHUNK_TYPE_DONT_CARE:
-			ret = process_skip_chunk(s, chunk_data_size, fd,
-					chunk_header->chunk_sz, cur_block, crc_ptr);
-			if (chunk_data_size != 0) {
-				if (ret < 0) {
-					verbose_error(s->verbose, ret, "skip block at %" PRId64, offset);
-					return ret;
-				}
-			}
-			return chunk_header->chunk_sz;
-		case CHUNK_TYPE_CRC32:
-			ret = process_crc32_chunk(fd, chunk_data_size, crc_ptr);
-			if (ret < 0) {
-				verbose_error(s->verbose, -EINVAL, "crc block at %" PRId64,
-						offset);
-				return ret;
-			}
-			return 0;
-		default:
-			verbose_error(s->verbose, -EINVAL, "unknown block %04X at %" PRId64,
-					chunk_header->chunk_type, offset);
-	}
+  switch (chunk_header->chunk_type) {
+    case CHUNK_TYPE_RAW:
+      ret =
+          process_raw_chunk(s, chunk_data_size, source, chunk_header->chunk_sz, cur_block, crc_ptr);
+      if (ret < 0) {
+        verbose_error(s->verbose, ret, "data block at %" PRId64, offset);
+        return ret;
+      }
+      return chunk_header->chunk_sz;
+    case CHUNK_TYPE_FILL:
+      ret = process_fill_chunk(s, chunk_data_size, source, chunk_header->chunk_sz, cur_block,
+                               crc_ptr);
+      if (ret < 0) {
+        verbose_error(s->verbose, ret, "fill block at %" PRId64, offset);
+        return ret;
+      }
+      return chunk_header->chunk_sz;
+    case CHUNK_TYPE_DONT_CARE:
+      ret = process_skip_chunk(s, chunk_data_size, source, chunk_header->chunk_sz, cur_block,
+                               crc_ptr);
+      if (chunk_data_size != 0) {
+        if (ret < 0) {
+          verbose_error(s->verbose, ret, "skip block at %" PRId64, offset);
+          return ret;
+        }
+      }
+      return chunk_header->chunk_sz;
+    case CHUNK_TYPE_CRC32:
+      ret = process_crc32_chunk(source, chunk_data_size, crc_ptr);
+      if (ret < 0) {
+        verbose_error(s->verbose, -EINVAL, "crc block at %" PRId64, offset);
+        return ret;
+      }
+      return 0;
+    default:
+      verbose_error(s->verbose, -EINVAL, "unknown block %04X at %" PRId64, chunk_header->chunk_type,
+                    offset);
+  }
 
-	return 0;
+  return 0;
 }
 
-static int sparse_file_read_sparse(struct sparse_file *s, int fd, bool crc)
-{
-	int ret;
-	unsigned int i;
-	sparse_header_t sparse_header;
-	chunk_header_t chunk_header;
-	uint32_t crc32 = 0;
-	uint32_t *crc_ptr = 0;
-	unsigned int cur_block = 0;
-	off64_t offset;
+static int sparse_file_read_sparse(struct sparse_file* s, SparseFileSource* source, bool crc) {
+  int ret;
+  unsigned int i;
+  sparse_header_t sparse_header;
+  chunk_header_t chunk_header;
+  uint32_t crc32 = 0;
+  uint32_t* crc_ptr = 0;
+  unsigned int cur_block = 0;
 
-	if (!copybuf) {
-		copybuf = (char *)malloc(COPY_BUF_SIZE);
-	}
+  if (!copybuf) {
+    copybuf = (char*)malloc(COPY_BUF_SIZE);
+  }
 
-	if (!copybuf) {
-		return -ENOMEM;
-	}
+  if (!copybuf) {
+    return -ENOMEM;
+  }
 
-	if (crc) {
-		crc_ptr = &crc32;
-	}
+  if (crc) {
+    crc_ptr = &crc32;
+  }
 
-	ret = read_all(fd, &sparse_header, sizeof(sparse_header));
-	if (ret < 0) {
-		return ret;
-	}
+  ret = source->ReadValue(&sparse_header, sizeof(sparse_header));
+  if (ret < 0) {
+    return ret;
+  }
 
-	if (sparse_header.magic != SPARSE_HEADER_MAGIC) {
-		return -EINVAL;
-	}
+  if (sparse_header.magic != SPARSE_HEADER_MAGIC) {
+    return -EINVAL;
+  }
 
-	if (sparse_header.major_version != SPARSE_HEADER_MAJOR_VER) {
-		return -EINVAL;
-	}
+  if (sparse_header.major_version != SPARSE_HEADER_MAJOR_VER) {
+    return -EINVAL;
+  }
 
-	if (sparse_header.file_hdr_sz < SPARSE_HEADER_LEN) {
-		return -EINVAL;
-	}
+  if (sparse_header.file_hdr_sz < SPARSE_HEADER_LEN) {
+    return -EINVAL;
+  }
 
-	if (sparse_header.chunk_hdr_sz < sizeof(chunk_header)) {
-		return -EINVAL;
-	}
+  if (sparse_header.chunk_hdr_sz < sizeof(chunk_header)) {
+    return -EINVAL;
+  }
 
-	if (sparse_header.file_hdr_sz > SPARSE_HEADER_LEN) {
-		/* Skip the remaining bytes in a header that is longer than
-		 * we expected.
-		 */
-		lseek64(fd, sparse_header.file_hdr_sz - SPARSE_HEADER_LEN, SEEK_CUR);
-	}
+  if (sparse_header.file_hdr_sz > SPARSE_HEADER_LEN) {
+    /* Skip the remaining bytes in a header that is longer than
+     * we expected.
+     */
+    source->Seek(sparse_header.file_hdr_sz - SPARSE_HEADER_LEN);
+  }
 
-	for (i = 0; i < sparse_header.total_chunks; i++) {
-		ret = read_all(fd, &chunk_header, sizeof(chunk_header));
-		if (ret < 0) {
-			return ret;
-		}
+  for (i = 0; i < sparse_header.total_chunks; i++) {
+    ret = source->ReadValue(&chunk_header, sizeof(chunk_header));
+    if (ret < 0) {
+      return ret;
+    }
 
-		if (sparse_header.chunk_hdr_sz > CHUNK_HEADER_LEN) {
-			/* Skip the remaining bytes in a header that is longer than
-			 * we expected.
-			 */
-			lseek64(fd, sparse_header.chunk_hdr_sz - CHUNK_HEADER_LEN, SEEK_CUR);
-		}
+    if (sparse_header.chunk_hdr_sz > CHUNK_HEADER_LEN) {
+      /* Skip the remaining bytes in a header that is longer than
+       * we expected.
+       */
+      source->Seek(sparse_header.chunk_hdr_sz - CHUNK_HEADER_LEN);
+    }
 
-		offset = lseek64(fd, 0, SEEK_CUR);
+    ret = process_chunk(s, source, sparse_header.chunk_hdr_sz, &chunk_header, cur_block, crc_ptr);
+    if (ret < 0) {
+      return ret;
+    }
 
-		ret = process_chunk(s, fd, offset, sparse_header.chunk_hdr_sz, &chunk_header,
-				cur_block, crc_ptr);
-		if (ret < 0) {
-			return ret;
-		}
+    cur_block += ret;
+  }
 
-		cur_block += ret;
-	}
+  if (sparse_header.total_blks != cur_block) {
+    return -EINVAL;
+  }
 
-	if (sparse_header.total_blks != cur_block) {
-		return -EINVAL;
-	}
-
-	return 0;
+  return 0;
 }
 
-static int sparse_file_read_normal(struct sparse_file *s, int fd)
-{
-	int ret;
-	uint32_t *buf = (uint32_t *)malloc(s->block_size);
-	unsigned int block = 0;
-	int64_t remain = s->len;
-	int64_t offset = 0;
-	unsigned int to_read;
-	unsigned int i;
-	bool sparse_block;
+static int sparse_file_read_normal(struct sparse_file* s, int fd) {
+  int ret;
+  uint32_t* buf = (uint32_t*)malloc(s->block_size);
+  unsigned int block = 0;
+  int64_t remain = s->len;
+  int64_t offset = 0;
+  unsigned int to_read;
+  unsigned int i;
+  bool sparse_block;
 
-	if (!buf) {
-		return -ENOMEM;
-	}
+  if (!buf) {
+    return -ENOMEM;
+  }
 
-	while (remain > 0) {
-		to_read = std::min(remain, (int64_t)(s->block_size));
-		ret = read_all(fd, buf, to_read);
-		if (ret < 0) {
-			error("failed to read sparse file");
-			free(buf);
-			return ret;
-		}
+  while (remain > 0) {
+    to_read = std::min(remain, (int64_t)(s->block_size));
+    ret = read_all(fd, buf, to_read);
+    if (ret < 0) {
+      error("failed to read sparse file");
+      free(buf);
+      return ret;
+    }
 
-		if (to_read == s->block_size) {
-			sparse_block = true;
-			for (i = 1; i < s->block_size / sizeof(uint32_t); i++) {
-				if (buf[0] != buf[i]) {
-					sparse_block = false;
-					break;
-				}
-			}
-		} else {
-			sparse_block = false;
-		}
+    if (to_read == s->block_size) {
+      sparse_block = true;
+      for (i = 1; i < s->block_size / sizeof(uint32_t); i++) {
+        if (buf[0] != buf[i]) {
+          sparse_block = false;
+          break;
+        }
+      }
+    } else {
+      sparse_block = false;
+    }
 
-		if (sparse_block) {
-			/* TODO: add flag to use skip instead of fill for buf[0] == 0 */
-			sparse_file_add_fill(s, buf[0], to_read, block);
-		} else {
-			sparse_file_add_fd(s, fd, offset, to_read, block);
-		}
+    if (sparse_block) {
+      /* TODO: add flag to use skip instead of fill for buf[0] == 0 */
+      sparse_file_add_fill(s, buf[0], to_read, block);
+    } else {
+      sparse_file_add_fd(s, fd, offset, to_read, block);
+    }
 
-		remain -= to_read;
-		offset += to_read;
-		block++;
-	}
+    remain -= to_read;
+    offset += to_read;
+    block++;
+  }
 
-	free(buf);
-	return 0;
+  free(buf);
+  return 0;
 }
 
-int sparse_file_read(struct sparse_file *s, int fd, bool sparse, bool crc)
-{
-	if (crc && !sparse) {
-		return -EINVAL;
-	}
+int sparse_file_read(struct sparse_file* s, int fd, bool sparse, bool crc) {
+  if (crc && !sparse) {
+    return -EINVAL;
+  }
 
-	if (sparse) {
-		return sparse_file_read_sparse(s, fd, crc);
-	} else {
-		return sparse_file_read_normal(s, fd);
-	}
+  if (sparse) {
+    SparseFileFdSource source(fd);
+    return sparse_file_read_sparse(s, &source, crc);
+  } else {
+    return sparse_file_read_normal(s, fd);
+  }
 }
 
-struct sparse_file *sparse_file_import(int fd, bool verbose, bool crc)
-{
-	int ret;
-	sparse_header_t sparse_header;
-	int64_t len;
-	struct sparse_file *s;
-
-	ret = read_all(fd, &sparse_header, sizeof(sparse_header));
-	if (ret < 0) {
-		verbose_error(verbose, ret, "header");
-		return NULL;
-	}
-
-	if (sparse_header.magic != SPARSE_HEADER_MAGIC) {
-		verbose_error(verbose, -EINVAL, "header magic");
-		return NULL;
-	}
-
-	if (sparse_header.major_version != SPARSE_HEADER_MAJOR_VER) {
-		verbose_error(verbose, -EINVAL, "header major version");
-		return NULL;
-	}
-
-	if (sparse_header.file_hdr_sz < SPARSE_HEADER_LEN) {
-		return NULL;
-	}
-
-	if (sparse_header.chunk_hdr_sz < sizeof(chunk_header_t)) {
-		return NULL;
-	}
-
-	len = (int64_t)sparse_header.total_blks * sparse_header.blk_sz;
-	s = sparse_file_new(sparse_header.blk_sz, len);
-	if (!s) {
-		verbose_error(verbose, -EINVAL, NULL);
-		return NULL;
-	}
-
-	ret = lseek64(fd, 0, SEEK_SET);
-	if (ret < 0) {
-		verbose_error(verbose, ret, "seeking");
-		sparse_file_destroy(s);
-		return NULL;
-	}
-
-	s->verbose = verbose;
-
-	ret = sparse_file_read(s, fd, true, crc);
-	if (ret < 0) {
-		sparse_file_destroy(s);
-		return NULL;
-	}
-
-	return s;
+int sparse_file_read_buf(struct sparse_file* s, char* buf, bool crc) {
+  SparseFileBufSource source(buf);
+  return sparse_file_read_sparse(s, &source, crc);
 }
 
-struct sparse_file *sparse_file_import_auto(int fd, bool crc, bool verbose)
-{
-	struct sparse_file *s;
-	int64_t len;
-	int ret;
+static struct sparse_file* sparse_file_import_source(SparseFileSource* source, bool verbose,
+                                                     bool crc) {
+  int ret;
+  sparse_header_t sparse_header;
+  int64_t len;
+  struct sparse_file* s;
 
-	s = sparse_file_import(fd, verbose, crc);
-	if (s) {
-		return s;
-	}
+  ret = source->ReadValue(&sparse_header, sizeof(sparse_header));
+  if (ret < 0) {
+    verbose_error(verbose, ret, "header");
+    return NULL;
+  }
 
-	len = lseek64(fd, 0, SEEK_END);
-	if (len < 0) {
-		return NULL;
-	}
+  if (sparse_header.magic != SPARSE_HEADER_MAGIC) {
+    verbose_error(verbose, -EINVAL, "header magic");
+    return NULL;
+  }
 
-	lseek64(fd, 0, SEEK_SET);
+  if (sparse_header.major_version != SPARSE_HEADER_MAJOR_VER) {
+    verbose_error(verbose, -EINVAL, "header major version");
+    return NULL;
+  }
 
-	s = sparse_file_new(4096, len);
-	if (!s) {
-		return NULL;
-	}
+  if (sparse_header.file_hdr_sz < SPARSE_HEADER_LEN) {
+    return NULL;
+  }
 
-	ret = sparse_file_read_normal(s, fd);
-	if (ret < 0) {
-		sparse_file_destroy(s);
-		return NULL;
-	}
+  if (sparse_header.chunk_hdr_sz < sizeof(chunk_header_t)) {
+    return NULL;
+  }
 
-	return s;
+  len = (int64_t)sparse_header.total_blks * sparse_header.blk_sz;
+  s = sparse_file_new(sparse_header.blk_sz, len);
+  if (!s) {
+    verbose_error(verbose, -EINVAL, NULL);
+    return NULL;
+  }
+
+  ret = source->SetOffset(0);
+  if (ret < 0) {
+    verbose_error(verbose, ret, "seeking");
+    sparse_file_destroy(s);
+    return NULL;
+  }
+
+  s->verbose = verbose;
+
+  ret = sparse_file_read_sparse(s, source, crc);
+  if (ret < 0) {
+    sparse_file_destroy(s);
+    return NULL;
+  }
+
+  return s;
+}
+
+struct sparse_file* sparse_file_import(int fd, bool verbose, bool crc) {
+  SparseFileFdSource source(fd);
+  return sparse_file_import_source(&source, verbose, crc);
+}
+
+struct sparse_file* sparse_file_import_buf(char* buf, bool verbose, bool crc) {
+  SparseFileBufSource source(buf);
+  return sparse_file_import_source(&source, verbose, crc);
+}
+
+struct sparse_file* sparse_file_import_auto(int fd, bool crc, bool verbose) {
+  struct sparse_file* s;
+  int64_t len;
+  int ret;
+
+  s = sparse_file_import(fd, verbose, crc);
+  if (s) {
+    return s;
+  }
+
+  len = lseek64(fd, 0, SEEK_END);
+  if (len < 0) {
+    return NULL;
+  }
+
+  lseek64(fd, 0, SEEK_SET);
+
+  s = sparse_file_new(4096, len);
+  if (!s) {
+    return NULL;
+  }
+
+  ret = sparse_file_read_normal(s, fd);
+  if (ret < 0) {
+    sparse_file_destroy(s);
+    return NULL;
+  }
+
+  return s;
 }
diff --git a/libsync/include/android/sync.h b/libsync/include/android/sync.h
index 68f74a0..32bb878 100644
--- a/libsync/include/android/sync.h
+++ b/libsync/include/android/sync.h
@@ -41,28 +41,8 @@
 
 __BEGIN_DECLS
 
-struct sync_fence_info_data {
- uint32_t len;
- char name[32];
- int32_t status;
- uint8_t pt_info[0];
-};
-
-struct sync_pt_info {
- uint32_t len;
- char obj_name[32];
- char driver_name[32];
- int32_t status;
- uint64_t timestamp_ns;
- uint8_t driver_data[0];
-};
-
 /* timeout in msecs */
 int sync_wait(int fd, int timeout);
-struct sync_fence_info_data *sync_fence_info(int fd);
-struct sync_pt_info *sync_pt_info(struct sync_fence_info_data *info,
-                                  struct sync_pt_info *itr);
-void sync_fence_info_free(struct sync_fence_info_data *info);
 
 __END_DECLS
 
diff --git a/libsync/sync.c b/libsync/sync.c
index 6b187fa..b8c48c7 100644
--- a/libsync/sync.c
+++ b/libsync/sync.c
@@ -30,6 +30,29 @@
 
 #include <android/sync.h>
 
+/* Prototypes for deprecated functions that used to be declared in the legacy
+ * android/sync.h. They've been moved here to make sure new code does not use
+ * them, but the functions are still defined to avoid breaking existing
+ * binaries. Eventually they can be removed altogether.
+ */
+struct sync_fence_info_data {
+    uint32_t len;
+    char name[32];
+    int32_t status;
+    uint8_t pt_info[0];
+};
+struct sync_pt_info {
+    uint32_t len;
+    char obj_name[32];
+    char driver_name[32];
+    int32_t status;
+    uint64_t timestamp_ns;
+    uint8_t driver_data[0];
+};
+struct sync_fence_info_data* sync_fence_info(int fd);
+struct sync_pt_info* sync_pt_info(struct sync_fence_info_data* info, struct sync_pt_info* itr);
+void sync_fence_info_free(struct sync_fence_info_data* info);
+
 /* Legacy Sync API */
 
 struct sync_legacy_merge_data {
diff --git a/libsync/tests/sync_test.cpp b/libsync/tests/sync_test.cpp
index 0fb86d6..011b09d 100644
--- a/libsync/tests/sync_test.cpp
+++ b/libsync/tests/sync_test.cpp
@@ -15,6 +15,35 @@
 #include <random>
 #include <unordered_map>
 
+/* These deprecated declarations were in the legacy android/sync.h. They've been removed to
+ * encourage code to move to the modern equivalents. But they are still implemented in libsync.so
+ * to avoid breaking existing binaries; as long as that's true we should keep testing them here.
+ * That means making local copies of the declarations.
+ */
+extern "C" {
+
+struct sync_fence_info_data {
+    uint32_t len;
+    char name[32];
+    int32_t status;
+    uint8_t pt_info[0];
+};
+
+struct sync_pt_info {
+    uint32_t len;
+    char obj_name[32];
+    char driver_name[32];
+    int32_t status;
+    uint64_t timestamp_ns;
+    uint8_t driver_data[0];
+};
+
+struct sync_fence_info_data* sync_fence_info(int fd);
+struct sync_pt_info* sync_pt_info(struct sync_fence_info_data* info, struct sync_pt_info* itr);
+void sync_fence_info_free(struct sync_fence_info_data* info);
+
+}  // extern "C"
+
 // TODO: better stress tests?
 // Handle more than 64 fd's simultaneously, i.e. fix sync_fence_info's 4k limit.
 // Handle wraparound in timelines like nvidia.
diff --git a/logd/main.cpp b/logd/main.cpp
index 5a588be..b697d44 100644
--- a/logd/main.cpp
+++ b/logd/main.cpp
@@ -87,30 +87,25 @@
 //
 
 static int drop_privs(bool klogd, bool auditd) {
-    // Tricky, if ro.build.type is "eng" then this is true because of the
-    // side effect that ro.debuggable == 1 as well, else it is false.
-    bool eng =
-        __android_logger_property_get_bool("ro.build.type", BOOL_DEFAULT_FALSE);
-
-    struct sched_param param;
-    memset(&param, 0, sizeof(param));
+    sched_param param = {};
 
     if (set_sched_policy(0, SP_BACKGROUND) < 0) {
         android::prdebug("failed to set background scheduling policy");
-        if (!eng) return -1;
+        return -1;
     }
 
     if (sched_setscheduler((pid_t)0, SCHED_BATCH, &param) < 0) {
         android::prdebug("failed to set batch scheduler");
-        if (!eng) return -1;
+        return -1;
     }
 
     if (setpriority(PRIO_PROCESS, 0, ANDROID_PRIORITY_BACKGROUND) < 0) {
         android::prdebug("failed to set background cgroup");
-        if (!eng) return -1;
+        return -1;
     }
 
-    if (!eng && (prctl(PR_SET_DUMPABLE, 0) < 0)) {
+    if (__android_logger_property_get_bool("ro.debuggable", BOOL_DEFAULT_FALSE) &&
+        prctl(PR_SET_DUMPABLE, 0) == -1) {
         android::prdebug("failed to clear PR_SET_DUMPABLE");
         return -1;
     }
@@ -133,24 +128,24 @@
         android::prdebug(
             "failed to set CAP_SETGID, CAP_SYSLOG or CAP_AUDIT_CONTROL (%d)",
             errno);
-        if (!eng) return -1;
+        return -1;
     }
 
     gid_t groups[] = { AID_READPROC };
 
     if (setgroups(arraysize(groups), groups) == -1) {
         android::prdebug("failed to set AID_READPROC groups");
-        if (!eng) return -1;
+        return -1;
     }
 
     if (setgid(AID_LOGD) != 0) {
         android::prdebug("failed to set AID_LOGD gid");
-        if (!eng) return -1;
+        return -1;
     }
 
     if (setuid(AID_LOGD) != 0) {
         android::prdebug("failed to set AID_LOGD uid");
-        if (!eng) return -1;
+        return -1;
     }
 
     if (cap_set_flag(caps.get(), CAP_PERMITTED, 1, cap_value, CAP_CLEAR) < 0) {
@@ -161,7 +156,7 @@
     }
     if (cap_set_proc(caps.get()) < 0) {
         android::prdebug("failed to clear CAP_SETGID (%d)", errno);
-        if (!eng) return -1;
+        return -1;
     }
 
     return 0;
@@ -468,7 +463,7 @@
     bool auditd =
         __android_logger_property_get_bool("ro.logd.auditd", BOOL_DEFAULT_TRUE);
     if (drop_privs(klogd, auditd) != 0) {
-        return -1;
+        return EXIT_FAILURE;
     }
 
     // Serves the purpose of managing the last logs times read on a
@@ -496,7 +491,7 @@
 
     LogReader* reader = new LogReader(logBuf);
     if (reader->startListener()) {
-        exit(1);
+        return EXIT_FAILURE;
     }
 
     // LogListener listens on /dev/socket/logdw for client
@@ -506,7 +501,7 @@
     LogListener* swl = new LogListener(logBuf, reader);
     // Backlog and /proc/sys/net/unix/max_dgram_qlen set to large value
     if (swl->startListener(600)) {
-        exit(1);
+        return EXIT_FAILURE;
     }
 
     // Command listener listens on /dev/socket/logd for incoming logd
@@ -514,7 +509,7 @@
 
     CommandListener* cl = new CommandListener(logBuf, reader, swl);
     if (cl->startListener()) {
-        exit(1);
+        return EXIT_FAILURE;
     }
 
     // LogAudit listens on NETLINK_AUDIT socket for selinux
@@ -549,5 +544,5 @@
 
     TEMP_FAILURE_RETRY(pause());
 
-    exit(0);
+    return EXIT_SUCCESS;
 }