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.cpp
similarity index 98%
rename from libsparse/append2simg.c
rename to libsparse/append2simg.cpp
index eef8764..83450a0 100644
--- a/libsparse/append2simg.c
+++ b/libsparse/append2simg.cpp
@@ -16,7 +16,6 @@
 
 #define _FILE_OFFSET_BITS 64
 #define _LARGEFILE64_SOURCE 1
-#define _GNU_SOURCE
 
 #include <errno.h>
 #include <fcntl.h>
diff --git a/libsparse/backed_block.c b/libsparse/backed_block.cpp
similarity index 92%
rename from libsparse/backed_block.c
rename to libsparse/backed_block.cpp
index 794cd6b..fb26d1a 100644
--- a/libsparse/backed_block.c
+++ b/libsparse/backed_block.cpp
@@ -122,7 +122,8 @@
 
 struct backed_block_list *backed_block_list_new(unsigned int block_size)
 {
-	struct backed_block_list *b = calloc(sizeof(struct backed_block_list), 1);
+	struct backed_block_list *b = reinterpret_cast<backed_block_list*>(
+            calloc(sizeof(struct backed_block_list), 1));
 	b->block_size = block_size;
 	return b;
 }
@@ -292,7 +293,7 @@
 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));
+	struct backed_block *bb = reinterpret_cast<backed_block*>(calloc(1, sizeof(struct backed_block)));
 	if (bb == NULL) {
 		return -ENOMEM;
 	}
@@ -310,7 +311,7 @@
 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));
+	struct backed_block *bb = reinterpret_cast<backed_block*>(calloc(1, sizeof(struct backed_block)));
 	if (bb == NULL) {
 		return -ENOMEM;
 	}
@@ -328,7 +329,7 @@
 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));
+	struct backed_block *bb = reinterpret_cast<backed_block*>(calloc(1, sizeof(struct backed_block)));
 	if (bb == NULL) {
 		return -ENOMEM;
 	}
@@ -347,7 +348,7 @@
 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));
+	struct backed_block *bb = reinterpret_cast<backed_block*>(calloc(1, sizeof(struct backed_block)));
 	if (bb == NULL) {
 		return -ENOMEM;
 	}
@@ -373,7 +374,7 @@
 		return 0;
 	}
 
-	new_bb = malloc(sizeof(struct backed_block));
+	new_bb = reinterpret_cast<backed_block*>(malloc(sizeof(struct backed_block)));
 	if (new_bb == NULL) {
 		return -ENOMEM;
 	}
diff --git a/libsparse/img2simg.c b/libsparse/img2simg.cpp
similarity index 100%
rename from libsparse/img2simg.c
rename to libsparse/img2simg.cpp
diff --git a/libsparse/output_file.c b/libsparse/output_file.cpp
similarity index 94%
rename from libsparse/output_file.c
rename to libsparse/output_file.cpp
index 002ad27..8d91550 100644
--- a/libsparse/output_file.c
+++ b/libsparse/output_file.cpp
@@ -326,7 +326,7 @@
 {
 	size_t total = 0;
 	int ret;
-	char *ptr = buf;
+	char *ptr = reinterpret_cast<char*>(buf);
 
 	while (total < len) {
 		ret = read(fd, ptr, len - total);
@@ -350,7 +350,7 @@
 	int ret;
 
 	if (skip_len % out->block_size) {
-		error("don't care size %"PRIi64" is not a multiple of the block size %u",
+		error("don't care size %" PRIi64 " is not a multiple of the block size %u",
 				skip_len, out->block_size);
 		return -1;
 	}
@@ -557,13 +557,13 @@
 	out->crc32 = 0;
 	out->use_crc = crc;
 
-	out->zero_buf = calloc(block_size, 1);
+	out->zero_buf = reinterpret_cast<char*>(calloc(block_size, 1));
 	if (!out->zero_buf) {
 		error_errno("malloc zero_buf");
 		return -ENOMEM;
 	}
 
-	out->fill_buf = calloc(block_size, 1);
+	out->fill_buf = reinterpret_cast<uint32_t*>(calloc(block_size, 1));
 	if (!out->fill_buf) {
 		error_errno("malloc fill_buf");
 		ret = -ENOMEM;
@@ -584,8 +584,8 @@
 				.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,
+				.total_blks = static_cast<unsigned>(DIV_ROUND_UP(out->len, out->block_size)),
+				.total_chunks = static_cast<unsigned>(chunks),
 				.image_checksum = 0
 		};
 
@@ -610,7 +610,8 @@
 
 static struct output_file *output_file_new_gz(void)
 {
-	struct output_file_gz *outgz = calloc(1, sizeof(struct output_file_gz));
+	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;
@@ -623,7 +624,8 @@
 
 static struct output_file *output_file_new_normal(void)
 {
-	struct output_file_normal *outn = calloc(1, sizeof(struct output_file_normal));
+	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;
@@ -642,7 +644,8 @@
 	int ret;
 	struct output_file_callback *outc;
 
-	outc = calloc(1, sizeof(struct output_file_callback));
+	outc = reinterpret_cast<struct output_file_callback*>(
+            calloc(1, sizeof(struct output_file_callback)));
 	if (!outc) {
 		error_errno("malloc struct outc");
 		return NULL;
@@ -716,15 +719,15 @@
 #ifndef _WIN32
 	if (buffer_size > SIZE_MAX)
 		return -E2BIG;
-	char *data = mmap64(NULL, buffer_size, PROT_READ, MAP_SHARED, fd,
-			aligned_offset);
+	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 = malloc(len);
+	char *data = reinterpret_cast<char*>(malloc(len));
 	if (!data) {
 		return -errno;
 	}
diff --git a/libsparse/simg2img.c b/libsparse/simg2img.cpp
similarity index 100%
rename from libsparse/simg2img.c
rename to libsparse/simg2img.cpp
diff --git a/libsparse/simg2simg.c b/libsparse/simg2simg.cpp
similarity index 98%
rename from libsparse/simg2simg.c
rename to libsparse/simg2simg.cpp
index 5f9ccf6..6f02f4f 100644
--- a/libsparse/simg2simg.c
+++ b/libsparse/simg2simg.cpp
@@ -16,7 +16,6 @@
 
 #define _FILE_OFFSET_BITS 64
 #define _LARGEFILE64_SOURCE 1
-#define _GNU_SOURCE
 
 #include <fcntl.h>
 #include <stdbool.h>
diff --git a/libsparse/sparse.c b/libsparse/sparse.cpp
similarity index 97%
rename from libsparse/sparse.c
rename to libsparse/sparse.cpp
index 466435f..992945f 100644
--- a/libsparse/sparse.c
+++ b/libsparse/sparse.cpp
@@ -29,7 +29,7 @@
 
 struct sparse_file *sparse_file_new(unsigned int block_size, int64_t len)
 {
-	struct sparse_file *s = calloc(sizeof(struct sparse_file), 1);
+	struct sparse_file *s = reinterpret_cast<sparse_file*>(calloc(sizeof(struct sparse_file), 1));
 	if (!s) {
 		return NULL;
 	}
@@ -209,7 +209,7 @@
 
 static int foreach_chunk_write(void *priv, const void *data, size_t len)
 {
-	struct chunk_data *chk = priv;
+	struct chunk_data *chk = reinterpret_cast<chunk_data*>(priv);
 
 	return chk->write(chk->priv, data, len, chk->block, chk->nr_blocks);
 }
@@ -252,7 +252,7 @@
 
 static int out_counter_write(void *priv, const void *data __unused, size_t len)
 {
-	int64_t *count = priv;
+	int64_t *count = reinterpret_cast<int64_t*>(priv);
 	*count += len;
 	return 0;
 }
diff --git a/libsparse/sparse_crc32.c b/libsparse/sparse_crc32.cpp
similarity index 96%
rename from libsparse/sparse_crc32.c
rename to libsparse/sparse_crc32.cpp
index 38bfe4a..97c5a10 100644
--- a/libsparse/sparse_crc32.c
+++ b/libsparse/sparse_crc32.cpp
@@ -44,6 +44,7 @@
 
 /* Code taken from FreeBSD 8 */
 #include <stdint.h>
+#include <stdio.h>
 
 static uint32_t crc32_tab[] = {
         0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
@@ -98,9 +99,9 @@
  * in sys/libkern.h, where it can be inlined.
  */
 
-uint32_t sparse_crc32(uint32_t crc_in, const void *buf, int size)
+uint32_t sparse_crc32(uint32_t crc_in, const void *buf, size_t size)
 {
-        const uint8_t *p = buf;
+        const uint8_t *p = reinterpret_cast<const uint8_t*>(buf);
         uint32_t crc;
 
         crc = crc_in ^ ~0U;
diff --git a/libsparse/sparse_crc32.h b/libsparse/sparse_crc32.h
index 50cd9e9..e42c1eb 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
-
 #endif
diff --git a/libsparse/sparse_err.c b/libsparse/sparse_err.cpp
similarity index 100%
rename from libsparse/sparse_err.c
rename to libsparse/sparse_err.cpp