diff --git a/fastboot/Android.mk b/fastboot/Android.mk
index 089b9bb..e3261a7 100644
--- a/fastboot/Android.mk
+++ b/fastboot/Android.mk
@@ -48,7 +48,7 @@
   LOCAL_C_INCLUDES += development/host/windows/usb/api
 endif
 
-LOCAL_STATIC_LIBRARIES := $(EXTRA_STATIC_LIBS) libzipfile libunz libext4_utils libz
+LOCAL_STATIC_LIBRARIES := $(EXTRA_STATIC_LIBS) libzipfile libunz libext4_utils libsparse libz
 
 ifneq ($(HOST_OS),windows)
 ifeq ($(HAVE_SELINUX), true)
diff --git a/fastboot/engine.c b/fastboot/engine.c
index f5215cf..8d7b68a 100644
--- a/fastboot/engine.c
+++ b/fastboot/engine.c
@@ -28,7 +28,6 @@
 
 #include "fastboot.h"
 #include "make_ext4fs.h"
-#include "ext4_utils.h"
 
 #include <stdio.h>
 #include <stdlib.h>
@@ -77,6 +76,7 @@
 #define OP_QUERY      3
 #define OP_NOTICE     4
 #define OP_FORMAT     5
+#define OP_DOWNLOAD_SPARSE 6
 
 typedef struct Action Action;
 
@@ -111,6 +111,20 @@
 void generate_ext4_image(struct image_data *image);
 void cleanup_image(struct image_data *image);
 
+int fb_getvar(struct usb_handle *usb, char *response, const char *fmt, ...)
+{
+    char cmd[CMD_SIZE] = "getvar:";
+    int getvar_len = strlen(cmd);
+    va_list args;
+
+    response[FB_RESPONSE_SZ] = '\0';
+    va_start(args, fmt);
+    vsnprintf(cmd + getvar_len, sizeof(cmd) - getvar_len, fmt, args);
+    va_end(args);
+    cmd[CMD_SIZE - 1] = '\0';
+    return fb_command_response(usb, cmd, response);
+}
+
 struct generator {
     char *fs_type;
 
@@ -278,9 +292,7 @@
     unsigned i;
     char cmd[CMD_SIZE];
 
-    response[FB_RESPONSE_SZ] = '\0';
-    snprintf(cmd, sizeof(cmd), "getvar:partition-type:%s", partition);
-    status = fb_command_response(usb, cmd, response);
+    status = fb_getvar(usb, response, "partition-type:%s", partition);
     if (status) {
         if (skip_if_not_supported) {
             fprintf(stderr,
@@ -312,9 +324,7 @@
         return -1;
     }
 
-    response[FB_RESPONSE_SZ] = '\0';
-    snprintf(cmd, sizeof(cmd), "getvar:partition-size:%s", partition);
-    status = fb_command_response(usb, cmd, response);
+    status = fb_getvar(usb, response, "partition-size:%s", partition);
     if (status) {
         if (skip_if_not_supported) {
             fprintf(stderr,
@@ -372,6 +382,19 @@
     a->msg = mkmsg("writing '%s'", ptn);
 }
 
+void fb_queue_flash_sparse(const char *ptn, struct sparse_file *s, unsigned sz)
+{
+    Action *a;
+
+    a = queue_action(OP_DOWNLOAD_SPARSE, "");
+    a->data = s;
+    a->size = 0;
+    a->msg = mkmsg("sending sparse '%s' (%d KB)", ptn, sz / 1024);
+
+    a = queue_action(OP_COMMAND, "flash:%s", ptn);
+    a->msg = mkmsg("writing '%s'", ptn);
+}
+
 static int match(char *str, const char **value, unsigned count)
 {
     const char *val;
@@ -572,6 +595,10 @@
             status = fb_format(a, usb, (int)a->data);
             status = a->func(a, status, status ? fb_get_error() : "");
             if (status) break;
+        } else if (a->op == OP_DOWNLOAD_SPARSE) {
+            status = fb_download_data_sparse(usb, a->data);
+            status = a->func(a, status, status ? fb_get_error() : "");
+            if (status) break;
         } else {
             die("bogus action");
         }
diff --git a/fastboot/fastboot.c b/fastboot/fastboot.c
index 544893b..6a14301 100644
--- a/fastboot/fastboot.c
+++ b/fastboot/fastboot.c
@@ -26,22 +26,36 @@
  * SUCH DAMAGE.
  */
 
+#define _LARGEFILE64_SOURCE
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
 #include <string.h>
 #include <errno.h>
 #include <fcntl.h>
 #include <unistd.h>
 #include <limits.h>
 #include <ctype.h>
+#include <getopt.h>
 
 #include <sys/time.h>
+#include <sys/types.h>
+
 #include <bootimg.h>
+#include <sparse/sparse.h>
 #include <zipfile/zipfile.h>
 
 #include "fastboot.h"
 
+#ifndef O_BINARY
+#define O_BINARY 0
+#endif
+
+#define DEFAULT_SPARSE_LIMIT (256 * 1024 * 1024)
+
 char cur_product[FB_RESPONSE_SZ + 1];
 
 void bootimg_set_cmdline(boot_img_hdr *h, const char *cmdline);
@@ -59,6 +73,8 @@
 static int wipe_data = 0;
 static unsigned short vendor_id = 0;
 static int long_listing = 0;
+static int64_t sparse_limit = -1;
+static int64_t target_sparse_limit = -1;
 
 static unsigned base_addr = 0x10000000;
 
@@ -117,7 +133,27 @@
 
 #ifdef _WIN32
 void *load_file(const char *fn, unsigned *_sz);
+int64_t file_size(const char *fn);
 #else
+#if defined(__APPLE__) && defined(__MACH__)
+#define lseek64 lseek
+#define off64_t off_t
+#endif
+
+int64_t file_size(const char *fn)
+{
+    off64_t off;
+    int fd;
+
+    fd = open(fn, O_RDONLY);
+    if (fd < 0) return -1;
+
+    off = lseek64(fd, 0, SEEK_END);
+    close(fd);
+
+    return off;
+}
+
 void *load_file(const char *fn, unsigned *_sz)
 {
     char *data;
@@ -259,6 +295,8 @@
             "  -i <vendor id>                           specify a custom USB vendor id\n"
             "  -b <base_addr>                           specify a custom kernel base address\n"
             "  -n <page size>                           specify the nand page size. default: 2048\n"
+            "  -S <size>[K|M|G]                         automatically sparse files greater than\n"
+            "                                           size. default: 256M, 0 to disable\n"
         );
 }
 
@@ -444,6 +482,110 @@
     fb_queue_notice("--------------------------------------------");
 }
 
+
+struct sparse_file **load_sparse_files(const char *fname, int max_size)
+{
+    int fd;
+    struct sparse_file *s;
+    int files;
+    struct sparse_file **out_s;
+
+    fd = open(fname, O_RDONLY | O_BINARY);
+    if (fd < 0) {
+        die("cannot open '%s'\n", fname);
+    }
+
+    s = sparse_file_import_auto(fd, false);
+    if (!s) {
+        die("cannot sparse read file '%s'\n", fname);
+    }
+
+    files = sparse_file_resparse(s, max_size, NULL, 0);
+    if (files < 0) {
+        die("Failed to resparse '%s'\n", fname);
+    }
+
+    out_s = calloc(sizeof(struct sparse_file *), files + 1);
+    if (!out_s) {
+        die("Failed to allocate sparse file array\n");
+    }
+
+    files = sparse_file_resparse(s, max_size, out_s, files);
+    if (files < 0) {
+        die("Failed to resparse '%s'\n", fname);
+    }
+
+    return out_s;
+}
+
+static int64_t get_target_sparse_limit(struct usb_handle *usb)
+{
+    int64_t limit = 0;
+    char response[FB_RESPONSE_SZ + 1];
+    int status = fb_getvar(usb, response, "max-download-size");
+
+    if (!status) {
+        limit = strtoul(response, NULL, 0);
+        if (limit > 0) {
+            fprintf(stderr, "target reported max download size of %lld bytes\n",
+                    limit);
+        }
+    }
+
+    return limit;
+}
+
+static int64_t get_sparse_limit(struct usb_handle *usb, int64_t size)
+{
+    int64_t limit;
+
+    if (sparse_limit == 0) {
+        return 0;
+    } else if (sparse_limit > 0) {
+        limit = sparse_limit;
+    } else {
+        if (target_sparse_limit == -1) {
+            target_sparse_limit = get_target_sparse_limit(usb);
+        }
+        if (target_sparse_limit > 0) {
+            limit = target_sparse_limit;
+        } else {
+            limit = DEFAULT_SPARSE_LIMIT;
+        }
+    }
+
+    if (size > limit) {
+        return limit;
+    }
+
+    return 0;
+}
+
+void do_flash(usb_handle *usb, const char *pname, const char *fname)
+{
+    int64_t sz64;
+    void *data;
+    int64_t limit;
+
+    sz64 = file_size(fname);
+    limit = get_sparse_limit(usb, sz64);
+    if (limit) {
+        struct sparse_file **s = load_sparse_files(fname, limit);
+        if (s == NULL) {
+            die("cannot sparse load '%s'\n", fname);
+        }
+        while (*s) {
+            sz64 = sparse_file_len(*s, true, false);
+            fb_queue_flash_sparse(pname, *s++, sz64);
+        }
+    } else {
+        unsigned int sz;
+        data = load_file(fname, &sz);
+        if (data == 0) die("cannot load '%s'\n", fname);
+        fb_queue_flash(pname, data, sz);
+    }
+}
+
 void do_update_signature(zipfile_t zip, char *fn)
 {
     void *data;
@@ -581,73 +723,136 @@
     return 0;
 }
 
+static int64_t parse_num(const char *arg)
+{
+    char *endptr;
+    unsigned long long num;
+
+    num = strtoull(arg, &endptr, 0);
+    if (endptr == arg) {
+        return -1;
+    }
+
+    if (*endptr == 'k' || *endptr == 'K') {
+        if (num >= (-1ULL) / 1024) {
+            return -1;
+        }
+        num *= 1024LL;
+        endptr++;
+    } else if (*endptr == 'm' || *endptr == 'M') {
+        if (num >= (-1ULL) / (1024 * 1024)) {
+            return -1;
+        }
+        num *= 1024LL * 1024LL;
+        endptr++;
+    } else if (*endptr == 'g' || *endptr == 'G') {
+        if (num >= (-1ULL) / (1024 * 1024 * 1024)) {
+            return -1;
+        }
+        num *= 1024LL * 1024LL * 1024LL;
+        endptr++;
+    }
+
+    if (*endptr != '\0') {
+        return -1;
+    }
+
+    if (num > INT64_MAX) {
+        return -1;
+    }
+
+    return num;
+}
+
 int main(int argc, char **argv)
 {
     int wants_wipe = 0;
     int wants_reboot = 0;
     int wants_reboot_bootloader = 0;
-    int wants_device_list = 0;
     void *data;
     unsigned sz;
     unsigned page_size = 2048;
     int status;
+    int c;
+    int r;
 
-    skip(1);
-    if (argc == 0) {
+    const struct option longopts = { 0, 0, 0, 0 };
+
+    serial = getenv("ANDROID_SERIAL");
+
+    while (1) {
+        c = getopt_long(argc, argv, "wb:n:s:S:lp:c:i:m:h", &longopts, NULL);
+        if (c < 0) {
+            break;
+        }
+
+        switch (c) {
+        case 'w':
+            wants_wipe = 1;
+            break;
+        case 'b':
+            base_addr = strtoul(optarg, 0, 16);
+            break;
+        case 'n':
+            page_size = (unsigned)strtoul(optarg, NULL, 0);
+            if (!page_size) die("invalid page size");
+            break;
+        case 's':
+            serial = optarg;
+            break;
+        case 'S':
+            sparse_limit = parse_num(optarg);
+            if (sparse_limit < 0) {
+                    die("invalid sparse limit");
+            }
+            break;
+        case 'l':
+            long_listing = 1;
+            break;
+        case 'p':
+            product = optarg;
+            break;
+        case 'c':
+            cmdline = optarg;
+            break;
+        case 'i': {
+                char *endptr = NULL;
+                unsigned long val;
+
+                val = strtoul(optarg, &endptr, 0);
+                if (!endptr || *endptr != '\0' || (val & ~0xffff))
+                    die("invalid vendor id '%s'", optarg);
+                vendor_id = (unsigned short)val;
+                break;
+            }
+        case 'h':
+            usage();
+            return 1;
+        case '?':
+            return 1;
+        default:
+            abort();
+        }
+    }
+
+    argc -= optind;
+    argv += optind;
+
+    if (argc == 0 && !wants_wipe) {
         usage();
         return 1;
     }
 
-    if (!strcmp(*argv, "help")) {
-        usage();
+    if (!strcmp(*argv, "devices")) {
+        skip(1);
+        list_devices();
         return 0;
     }
 
-
-    serial = getenv("ANDROID_SERIAL");
+    usb = open_device();
 
     while (argc > 0) {
-        if(!strcmp(*argv, "-w")) {
-            wants_wipe = 1;
-            skip(1);
-        } else if(!strcmp(*argv, "-b")) {
-            require(2);
-            base_addr = strtoul(argv[1], 0, 16);
-            skip(2);
-        } else if(!strcmp(*argv, "-n")) {
-            require(2);
-            page_size = (unsigned)strtoul(argv[1], NULL, 0);
-            if (!page_size) die("invalid page size");
-            skip(2);
-        } else if(!strcmp(*argv, "-s")) {
-            require(2);
-            serial = argv[1];
-            skip(2);
-        } else if(!strcmp(*argv, "-l")) {
-            long_listing = 1;
-            skip(1);
-        } else if(!strcmp(*argv, "-p")) {
-            require(2);
-            product = argv[1];
-            skip(2);
-        } else if(!strcmp(*argv, "-c")) {
-            require(2);
-            cmdline = argv[1];
-            skip(2);
-        } else if(!strcmp(*argv, "-i")) {
-            char *endptr = NULL;
-            unsigned long val;
-
-            require(2);
-            val = strtoul(argv[1], &endptr, 0);
-            if (!endptr || *endptr != '\0' || (val & ~0xffff))
-                die("invalid vendor id '%s'", argv[1]);
-            vendor_id = (unsigned short)val;
-            skip(2);
-        } else if (!strcmp(*argv, "devices")) {
-            skip(1);
-            wants_device_list = 1;
-        } else if(!strcmp(*argv, "getvar")) {
+        if(!strcmp(*argv, "getvar")) {
             require(2);
             fb_queue_display(argv[1], argv[1]);
             skip(2);
@@ -704,9 +909,7 @@
                 skip(2);
             }
             if (fname == 0) die("cannot determine image filename for '%s'", pname);
-            data = load_file(fname, &sz);
-            if (data == 0) die("cannot load '%s'\n", fname);
-            fb_queue_flash(pname, data, sz);
+            do_flash(usb, pname, fname);
         } else if(!strcmp(*argv, "flash:raw")) {
             char *pname = argv[1];
             char *kname = argv[2];
@@ -736,15 +939,15 @@
             wants_reboot = 1;
         } else if(!strcmp(*argv, "oem")) {
             argc = do_oem_command(argc, argv);
+        } else if (!strcmp(*argv, "help")) {
+            usage();
+            return 0;
         } else {
             usage();
             return 1;
         }
     }
 
-    if (wants_device_list)
-        list_devices();
-
     if (wants_wipe) {
         fb_queue_erase("userdata");
         fb_queue_format("userdata", 1);
@@ -760,8 +963,6 @@
     if (fb_queue_is_empty())
         return 0;
 
-    usb = open_device();
-
     status = fb_execute_queue(usb);
     return (status) ? 1 : 0;
 }
diff --git a/fastboot/fastboot.h b/fastboot/fastboot.h
index 90d8a6a..b4cf195 100644
--- a/fastboot/fastboot.h
+++ b/fastboot/fastboot.h
@@ -31,17 +31,22 @@
 
 #include "usb.h"
 
+struct sparse_file;
+
 /* protocol.c - fastboot protocol */
 int fb_command(usb_handle *usb, const char *cmd);
 int fb_command_response(usb_handle *usb, const char *cmd, char *response);
 int fb_download_data(usb_handle *usb, const void *data, unsigned size);
+int fb_download_data_sparse(usb_handle *usb, struct sparse_file *s);
 char *fb_get_error(void);
 
 #define FB_COMMAND_SZ 64
 #define FB_RESPONSE_SZ 64
 
 /* engine.c - high level command queue engine */
+int fb_getvar(struct usb_handle *usb, char *response, const char *fmt, ...);
 void fb_queue_flash(const char *ptn, void *data, unsigned sz);;
+void fb_queue_flash_sparse(const char *ptn, struct sparse_file *s, unsigned sz);
 void fb_queue_erase(const char *ptn);
 void fb_queue_format(const char *ptn, int skip_if_not_supported);
 void fb_queue_require(const char *prod, const char *var, int invert,
diff --git a/fastboot/protocol.c b/fastboot/protocol.c
index e871113..a0e0fd4 100644
--- a/fastboot/protocol.c
+++ b/fastboot/protocol.c
@@ -26,11 +26,18 @@
  * SUCH DAMAGE.
  */
 
+#define min(a, b) \
+    ({ typeof(a) _a = (a); typeof(b) _b = (b); (_a < _b) ? _a : _b; })
+#define round_down(a, b) \
+    ({ typeof(a) _a = (a); typeof(b) _b = (b); _a - (_a % _b); })
+
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
 
+#include <sparse/sparse.h>
+
 #include "fastboot.h"
 
 static char ERROR[128];
@@ -40,8 +47,7 @@
     return ERROR;
 }
 
-static int check_response(usb_handle *usb, unsigned size,
-                          unsigned data_okay, char *response)
+static int check_response(usb_handle *usb, unsigned int size, char *response)
 {
     unsigned char status[65];
     int r;
@@ -82,7 +88,7 @@
             return -1;
         }
 
-        if(!memcmp(status, "DATA", 4) && data_okay){
+        if(!memcmp(status, "DATA", 4) && size > 0){
             unsigned dsize = strtoul((char*) status + 4, 0, 16);
             if(dsize > size) {
                 strcpy(ERROR, "data size too large");
@@ -100,9 +106,8 @@
     return -1;
 }
 
-static int _command_send(usb_handle *usb, const char *cmd,
-                         const void *data, unsigned size,
-                         char *response)
+static int _command_start(usb_handle *usb, const char *cmd, unsigned size,
+                          char *response)
 {
     int cmdsize = strlen(cmd);
     int r;
@@ -122,46 +127,81 @@
         return -1;
     }
 
-    if(data == 0) {
-        return check_response(usb, size, 0, response);
+    return check_response(usb, size, response);
+}
+
+static int _command_data(usb_handle *usb, const void *data, unsigned size)
+{
+    int r;
+
+    r = usb_write(usb, data, size);
+    if(r < 0) {
+        sprintf(ERROR, "data transfer failure (%s)", strerror(errno));
+        usb_close(usb);
+        return -1;
+    }
+    if(r != ((int) size)) {
+        sprintf(ERROR, "data transfer failure (short transfer)");
+        usb_close(usb);
+        return -1;
     }
 
-    r = check_response(usb, size, 1, 0);
+    return r;
+}
+
+static int _command_end(usb_handle *usb)
+{
+    int r;
+    r = check_response(usb, 0, 0);
     if(r < 0) {
         return -1;
     }
-    size = r;
+    return 0;
+}
 
-    if(size) {
-        r = usb_write(usb, data, size);
-        if(r < 0) {
-            sprintf(ERROR, "data transfer failure (%s)", strerror(errno));
-            usb_close(usb);
-            return -1;
-        }
-        if(r != ((int) size)) {
-            sprintf(ERROR, "data transfer failure (short transfer)");
-            usb_close(usb);
-            return -1;
-        }
+static int _command_send(usb_handle *usb, const char *cmd,
+                         const void *data, unsigned size,
+                         char *response)
+{
+    int r;
+    if (size == 0) {
+        return -1;
     }
 
-    r = check_response(usb, 0, 0, 0);
+    r = _command_start(usb, cmd, size, response);
+    if (r < 0) {
+        return -1;
+    }
+
+    r = _command_data(usb, data, size);
+    if (r < 0) {
+        return -1;
+    }
+
+    r = _command_end(usb);
     if(r < 0) {
         return -1;
-    } else {
-        return size;
     }
+
+    return size;
+}
+
+static int _command_send_no_data(usb_handle *usb, const char *cmd,
+                                 char *response)
+{
+    int r;
+
+    return _command_start(usb, cmd, 0, response);
 }
 
 int fb_command(usb_handle *usb, const char *cmd)
 {
-    return _command_send(usb, cmd, 0, 0, 0);
+    return _command_send_no_data(usb, cmd, 0);
 }
 
 int fb_command_response(usb_handle *usb, const char *cmd, char *response)
 {
-    return _command_send(usb, cmd, 0, 0, response);
+    return _command_send_no_data(usb, cmd, response);
 }
 
 int fb_download_data(usb_handle *usb, const void *data, unsigned size)
@@ -179,3 +219,96 @@
     }
 }
 
+#define USB_BUF_SIZE 512
+static char usb_buf[USB_BUF_SIZE];
+static int usb_buf_len;
+
+static int fb_download_data_sparse_write(void *priv, const void *data, int len)
+{
+    int r;
+    usb_handle *usb = priv;
+    int to_write;
+    const char *ptr = data;
+
+    if (usb_buf_len) {
+        to_write = min(USB_BUF_SIZE - usb_buf_len, len);
+
+        memcpy(usb_buf + usb_buf_len, ptr, to_write);
+        usb_buf_len += to_write;
+        ptr += to_write;
+        len -= to_write;
+    }
+
+    if (usb_buf_len == USB_BUF_SIZE) {
+        r = _command_data(usb, usb_buf, USB_BUF_SIZE);
+        if (r != USB_BUF_SIZE) {
+            return -1;
+        }
+        usb_buf_len = 0;
+    }
+
+    if (len > USB_BUF_SIZE) {
+        if (usb_buf_len > 0) {
+            sprintf(ERROR, "internal error: usb_buf not empty\n");
+            return -1;
+        }
+        to_write = round_down(len, USB_BUF_SIZE);
+        r = _command_data(usb, ptr, to_write);
+        if (r != to_write) {
+            return -1;
+        }
+        ptr += to_write;
+        len -= to_write;
+    }
+
+    if (len > 0) {
+        if (len > USB_BUF_SIZE) {
+            sprintf(ERROR, "internal error: too much left for usb_buf\n");
+            return -1;
+        }
+        memcpy(usb_buf, ptr, len);
+        usb_buf_len = len;
+    }
+
+    return 0;
+}
+
+static int fb_download_data_sparse_flush(usb_handle *usb)
+{
+    int r;
+
+    if (usb_buf_len > 0) {
+        r = _command_data(usb, usb_buf, usb_buf_len);
+        if (r != usb_buf_len) {
+            return -1;
+        }
+        usb_buf_len = 0;
+    }
+
+    return 0;
+}
+
+int fb_download_data_sparse(usb_handle *usb, struct sparse_file *s)
+{
+    char cmd[64];
+    int r;
+    int size = sparse_file_len(s, true, false);
+    if (size <= 0) {
+        return -1;
+    }
+
+    sprintf(cmd, "download:%08x", size);
+    r = _command_start(usb, cmd, size, 0);
+    if (r < 0) {
+        return -1;
+    }
+
+    r = sparse_file_callback(s, true, false, fb_download_data_sparse_write, usb);
+    if (r < 0) {
+        return -1;
+    }
+
+    fb_download_data_sparse_flush(usb);
+
+    return _command_end(usb);
+}
diff --git a/fastboot/util_windows.c b/fastboot/util_windows.c
index c3d545c..9e029fd 100644
--- a/fastboot/util_windows.c
+++ b/fastboot/util_windows.c
@@ -36,6 +36,29 @@
 
 #include <windows.h>
 
+int64_t file_size(const char *fn)
+{
+    HANDLE    file;
+    char     *data;
+    DWORD     sz;
+
+    file = CreateFile( fn,
+                       GENERIC_READ,
+                       FILE_SHARE_READ,
+                       NULL,
+                       OPEN_EXISTING,
+                       0,
+                       NULL );
+
+    if (file == INVALID_HANDLE_VALUE)
+        return -1;
+
+    sz = GetFileSize( file, NULL );
+    CloseHandle( file );
+
+    return sz;
+}
+
 void get_my_path(char exe[PATH_MAX])
 {
 	char*  r;
@@ -52,7 +75,7 @@
 {
     HANDLE    file;
     char     *data;
-    DWORD     file_size;
+    DWORD     sz;
 
     file = CreateFile( fn,
                        GENERIC_READ,
@@ -65,29 +88,29 @@
     if (file == INVALID_HANDLE_VALUE)
         return NULL;
 
-    file_size = GetFileSize( file, NULL );
+    sz = GetFileSize( file, NULL );
     data      = NULL;
 
-    if (file_size > 0) {
-        data = (char*) malloc( file_size );
+    if (sz > 0) {
+        data = (char*) malloc( sz );
         if (data == NULL) {
-            fprintf(stderr, "load_file: could not allocate %ld bytes\n", file_size );
-            file_size = 0;
+            fprintf(stderr, "load_file: could not allocate %ld bytes\n", sz );
+            sz = 0;
         } else {
             DWORD  out_bytes;
 
-            if ( !ReadFile( file, data, file_size, &out_bytes, NULL ) ||
-                 out_bytes != file_size )
+            if ( !ReadFile( file, data, sz, &out_bytes, NULL ) ||
+                 out_bytes != sz )
             {
-                fprintf(stderr, "load_file: could not read %ld bytes from '%s'\n", file_size, fn);
+                fprintf(stderr, "load_file: could not read %ld bytes from '%s'\n", sz, fn);
                 free(data);
                 data      = NULL;
-                file_size = 0;
+                sz = 0;
             }
         }
     }
     CloseHandle( file );
 
-    *_sz = (unsigned) file_size;
+    *_sz = (unsigned) sz;
     return  data;
 }
diff --git a/libsparse/Android.mk b/libsparse/Android.mk
new file mode 100644
index 0000000..69b52c3
--- /dev/null
+++ b/libsparse/Android.mk
@@ -0,0 +1,101 @@
+# Copyright 2010 The Android Open Source Project
+
+LOCAL_PATH:= $(call my-dir)
+
+libsparse_src_files := \
+        backed_block.c \
+        output_file.c \
+        sparse.c \
+        sparse_crc32.c \
+        sparse_err.c \
+        sparse_read.c
+
+include $(CLEAR_VARS)
+
+LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)/include
+LOCAL_SRC_FILES := $(libsparse_src_files)
+LOCAL_MODULE := libsparse
+LOCAL_MODULE_TAGS := optional
+LOCAL_STATIC_LIBRARIES := libz
+LOCAL_C_INCLUDES += $(LOCAL_PATH)/include external/zlib
+
+include $(BUILD_HOST_STATIC_LIBRARY)
+
+include $(CLEAR_VARS)
+
+LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)/include
+LOCAL_SRC_FILES := $(libsparse_src_files)
+LOCAL_MODULE := libsparse
+LOCAL_MODULE_TAGS := optional
+LOCAL_C_INCLUDES += $(LOCAL_PATH)/include external/zlib
+LOCAL_SHARED_LIBRARIES := libz
+
+include $(BUILD_SHARED_LIBRARY)
+
+include $(CLEAR_VARS)
+
+LOCAL_EXPORT_C_INCLUDE_DIRS := $(LOCAL_PATH)/include
+LOCAL_SRC_FILES := $(libsparse_src_files)
+LOCAL_MODULE := libsparse
+LOCAL_MODULE_TAGS := optional
+LOCAL_C_INCLUDES += $(LOCAL_PATH)/include external/zlib
+LOCAL_STATIC_LIBRARIES := libz
+
+include $(BUILD_STATIC_LIBRARY)
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := simg2img.c \
+	sparse_crc32.c
+LOCAL_MODULE := simg2img
+LOCAL_MODULE_TAGS := debug
+LOCAL_STATIC_LIBRARIES := libsparse libz
+
+include $(BUILD_HOST_EXECUTABLE)
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := simg2img.c \
+	sparse_crc32.c
+LOCAL_MODULE := simg2img
+LOCAL_MODULE_TAGS := optional
+LOCAL_STATIC_LIBRARIES := libsparse libz
+
+include $(BUILD_EXECUTABLE)
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := img2simg.c
+LOCAL_MODULE := img2simg
+LOCAL_MODULE_TAGS := debug
+LOCAL_STATIC_LIBRARIES := libsparse libz
+
+include $(BUILD_HOST_EXECUTABLE)
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := img2simg.c
+LOCAL_MODULE := img2simg
+LOCAL_MODULE_TAGS := optional
+LOCAL_STATIC_LIBRARIES := libsparse libz
+
+include $(BUILD_EXECUTABLE)
+
+include $(CLEAR_VARS)
+
+LOCAL_SRC_FILES := simg2simg.c
+LOCAL_MODULE := simg2simg
+LOCAL_MODULE_TAGS := debug
+LOCAL_STATIC_LIBRARIES := libsparse libz
+
+include $(BUILD_HOST_EXECUTABLE)
+
+include $(CLEAR_VARS)
+
+LOCAL_MODULE := simg_dump.py
+LOCAL_MODULE_TAGS := debug
+LOCAL_SRC_FILES := simg_dump.py
+LOCAL_MODULE_CLASS := EXECUTABLES
+LOCAL_IS_HOST_MODULE := true
+
+include $(BUILD_PREBUILT)
diff --git a/libsparse/backed_block.c b/libsparse/backed_block.c
new file mode 100644
index 0000000..dfb217b
--- /dev/null
+++ b/libsparse/backed_block.c
@@ -0,0 +1,400 @@
+/*
+ * 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:
+		if (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);
+	merge_bb(bbl, bb, new_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 (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
new file mode 100644
index 0000000..1a159be
--- /dev/null
+++ b/libsparse/backed_block.h
@@ -0,0 +1,64 @@
+/*
+ * 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.
+ */
+
+#ifndef _BACKED_BLOCK_H_
+#define _BACKED_BLOCK_H_
+
+#include <stdint.h>
+
+struct backed_block_list;
+struct backed_block;
+
+enum backed_block_type {
+	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);
+
+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_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);
+
+#endif
diff --git a/libsparse/img2simg.c b/libsparse/img2simg.c
new file mode 100644
index 0000000..6b1caa5
--- /dev/null
+++ b/libsparse/img2simg.c
@@ -0,0 +1,116 @@
+/*
+ * 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;
+	unsigned int i;
+	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
new file mode 100644
index 0000000..17d085c
--- /dev/null
+++ b/libsparse/include/sparse/sparse.h
@@ -0,0 +1,276 @@
+/*
+ * 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.
+ */
+
+#ifndef _LIBSPARSE_SPARSE_H_
+#define _LIBSPARSE_SPARSE_H_
+
+#include <stdbool.h>
+#include <stdint.h>
+
+struct sparse_file;
+
+/**
+ * sparse_file_new - create a new sparse file cookie
+ *
+ * @block_size - minimum size of a chunk
+ * @len - size of the expanded sparse file.
+ *
+ * Creates a new sparse_file cookie that can be used to associate data
+ * blocks.  Can later be written to a file with a variety of options.
+ * block_size specifies the minimum size of a chunk in the file.  The maximum
+ * size of the file is 2**32 * block_size (16TB for 4k block size).
+ *
+ * Returns the sparse file cookie, or NULL on error.
+ */
+struct sparse_file *sparse_file_new(unsigned int block_size, int64_t len);
+
+/**
+ * sparse_file_destroy - destroy a sparse file cookie
+ *
+ * @s - sparse file cookie
+ *
+ * Destroys a sparse file cookie.  After destroy, all memory passed in to
+ * sparse_file_add_data can be freed by the caller
+ */
+void sparse_file_destroy(struct sparse_file *s);
+
+/**
+ * sparse_file_add_data - associate a data chunk with a sparse file
+ *
+ * @s - sparse file cookie
+ * @data - pointer to data block
+ * @len - length of the data block
+ * @block - offset in blocks into the sparse file to place the data chunk
+ *
+ * Associates a data chunk with a sparse file cookie.  The region
+ * [block * block_size : block * block_size + len) must not already be used in
+ * the sparse file. If len is not a multiple of the block size the data
+ * will be padded with zeros.
+ *
+ * The data pointer must remain valid until the sparse file is closed or the
+ * data block is removed from the sparse file.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int sparse_file_add_data(struct sparse_file *s,
+		void *data, unsigned int len, unsigned int block);
+
+/**
+ * sparse_file_add_fill - associate a fill chunk with a sparse file
+ *
+ * @s - sparse file cookie
+ * @fill_val - 32 bit fill data
+ * @len - length of the fill block
+ * @block - offset in blocks into the sparse file to place the fill chunk
+ *
+ * Associates a chunk filled with fill_val with a sparse file cookie.
+ * The region [block * block_size : block * block_size + len) must not already
+ * be used in the sparse file. If len is not a multiple of the block size the
+ * data will be padded with zeros.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int sparse_file_add_fill(struct sparse_file *s,
+		uint32_t fill_val, unsigned int len, unsigned int block);
+
+/**
+ * sparse_file_add_file - associate a chunk of a file with a sparse file
+ *
+ * @s - sparse file cookie
+ * @filename - filename of the file to be copied
+ * @file_offset - offset into the copied file
+ * @len - length of the copied block
+ * @block - offset in blocks into the sparse file to place the file chunk
+ *
+ * Associates a chunk of an existing file with a sparse file cookie.
+ * The region [block * block_size : block * block_size + len) must not already
+ * be used in the sparse file. If len is not a multiple of the block size the
+ * data will be padded with zeros.
+ *
+ * Allows adding large amounts of data to a sparse file without needing to keep
+ * it all mapped.  File size is limited by available virtual address space,
+ * exceptionally large files may need to be added in multiple chunks.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int sparse_file_add_file(struct sparse_file *s,
+		const char *filename, int64_t file_offset, unsigned int len,
+		unsigned int block);
+
+/**
+ * sparse_file_add_file - associate a chunk of a file with a sparse file
+ *
+ * @s - sparse file cookie
+ * @filename - filename of the file to be copied
+ * @file_offset - offset into the copied file
+ * @len - length of the copied block
+ * @block - offset in blocks into the sparse file to place the file chunk
+ *
+ * Associates a chunk of an existing fd with a sparse file cookie.
+ * The region [block * block_size : block * block_size + len) must not already
+ * be used in the sparse file. If len is not a multiple of the block size the
+ * data will be padded with zeros.
+ *
+ * Allows adding large amounts of data to a sparse file without needing to keep
+ * it all mapped.  File size is limited by available virtual address space,
+ * exceptionally large files may need to be added in multiple chunks.
+ *
+ * The fd must remain open until the sparse file is closed or the fd block is
+ * removed from the sparse file.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int sparse_file_add_fd(struct sparse_file *s,
+		int fd, int64_t file_offset, unsigned int len, unsigned int block);
+
+/**
+ * sparse_file_write - write a sparse file to a file
+ *
+ * @s - sparse file cookie
+ * @fd - file descriptor to write to
+ * @gz - write a gzipped file
+ * @sparse - write in the Android sparse file format
+ * @crc - append a crc chunk
+ *
+ * Writes a sparse file to a file.  If gz is true, the data will be passed
+ * through zlib.  If sparse is true, the file will be written in the Android
+ * sparse file format.  If sparse is false, the file will be written by seeking
+ * over unused chunks, producing a smaller file if the filesystem supports
+ * sparse files.  If crc is true, the crc of the expanded data will be
+ * calculated and appended in a crc chunk.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int sparse_file_write(struct sparse_file *s, int fd, bool gz, bool sparse,
+		bool crc);
+
+/**
+ * sparse_file_len - return the length of a sparse file if written to disk
+ *
+ * @s - sparse file cookie
+ * @sparse - write in the Android sparse file format
+ * @crc - append a crc chunk
+ *
+ * Returns the size a sparse file would be on disk if it were written in the
+ * specified format.  If sparse is true, this is the size of the data in the
+ * sparse format.  If sparse is false, this is the size of the normal
+ * non-sparse file.
+ */
+int64_t sparse_file_len(struct sparse_file *s, bool sparse, bool crc);
+
+/**
+ * sparse_file_callback - call a callback for blocks in sparse file
+ *
+ * @s - sparse file cookie
+ * @sparse - write in the Android sparse file format
+ * @crc - append a crc chunk
+ * @write - function to call for each block
+ * @priv - value that will be passed as the first argument to write
+ *
+ * Writes a sparse file by calling a callback function.  If sparse is true, the
+ * file will be written in the Android sparse file format.  If crc is true, the
+ * crc of the expanded data will be calculated and appended in a crc chunk.
+ * The callback 'write' will be called with data and length for each data,
+ * and with data==NULL to skip over a region (only used for non-sparse format).
+ * The callback should return negative on error, 0 on success.
+ *
+ * Returns 0 on success, negative errno on error.
+ */
+int sparse_file_callback(struct sparse_file *s, bool sparse, bool crc,
+		int (*write)(void *priv, const void *data, int len), void *priv);
+
+/**
+ * sparse_file_read - read a file into a sparse file cookie
+ *
+ * @s - sparse file cookie
+ * @fd - file descriptor to read from
+ * @sparse - read a file in the Android sparse file format
+ * @crc - verify the crc of a file in the Android sparse file format
+ *
+ * Reads a file into a sparse file cookie.  If sparse is true, the file is
+ * assumed to be in the Android sparse file format.  If sparse is false, the
+ * file will be sparsed by looking for block aligned chunks of all zeros or
+ * another 32 bit value.  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(struct sparse_file *s, int fd, bool sparse, bool crc);
+
+/**
+ * sparse_file_import - import an existing sparse file
+ *
+ * @s - sparse file cookie
+ * @verbose - print verbose errors while reading the sparse file
+ * @crc - verify the crc of a file in the Android sparse file format
+ *
+ * Reads an existing sparse file 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(int fd, bool verbose, bool crc);
+
+/**
+ * sparse_file_import_auto - import an existing sparse or normal file
+ *
+ * @fd - file descriptor to read from
+ * @crc - verify the crc of a file in the Android sparse file format
+ *
+ * Reads an existing sparse or normal file into a sparse file cookie.
+ * Attempts to determine if the file is sparse or not by looking for the sparse
+ * file magic number in the first 4 bytes.  If the file is not sparse, the file
+ * will be sparsed by looking for block aligned chunks of all zeros or another
+ * 32 bit value.  If crc is true, the crc of the sparse file will be verified.
+ *
+ * Returns a new sparse file cookie on success, NULL on error.
+ */
+struct sparse_file *sparse_file_import_auto(int fd, bool crc);
+
+/** sparse_file_resparse - rechunk an existing sparse file into smaller files
+ *
+ * @in_s - sparse file cookie of the existing sparse file
+ * @max_len - maximum file size
+ * @out_s - array of sparse file cookies
+ * @out_s_count - size of out_s array
+ *
+ * Splits chunks of an existing sparse file into smaller sparse files such that
+ * each sparse file is less than max_len.  Returns the number of sparse_files
+ * that would have been written to out_s if out_s were big enough.
+ */
+int sparse_file_resparse(struct sparse_file *in_s, unsigned int max_len,
+		struct sparse_file **out_s, int out_s_count);
+
+/**
+ * sparse_file_verbose - set a sparse file cookie to print verbose errors
+ *
+ * @s - sparse file cookie
+ *
+ * Print verbose sparse file errors whenever using the sparse file cookie.
+ */
+void sparse_file_verbose(struct sparse_file *s);
+
+/**
+ * sparse_print_verbose - function called to print verbose errors
+ *
+ * By default, verbose errors will print to standard error.
+ * sparse_print_verbose may be overridden to log verbose errors somewhere else.
+ *
+ */
+extern void (*sparse_print_verbose)(const char *fmt, ...);
+
+#endif
diff --git a/libsparse/output_file.c b/libsparse/output_file.c
new file mode 100644
index 0000000..b5ae419
--- /dev/null
+++ b/libsparse/output_file.c
@@ -0,0 +1,772 @@
+/*
+ * 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 <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 "output_file.h"
+#include "sparse_format.h"
+#include "sparse_crc32.h"
+
+#ifndef USE_MINGW
+#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
+
+#ifdef __BIONIC__
+extern void*  __mmap2(void *, size_t, int, int, int, off_t);
+static inline void *mmap64(void *addr, size_t length, int prot, int flags,
+        int fd, off64_t offset)
+{
+    return __mmap2(addr, length, prot, flags, fd, offset >> 12);
+}
+#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 *, int);
+	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, int 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, int len)
+{
+	int ret;
+	struct output_file_normal *outn = to_output_file_normal(out);
+
+	ret = write(outn->fd, data, len);
+	if (ret < 0) {
+		error_errno("write");
+		return -1;
+	} else if (ret < len) {
+		error("incomplete write");
+		return -1;
+	}
+
+	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, int len)
+{
+	int ret;
+	struct output_file_gz *outgz = to_output_file_gz(out);
+
+	ret = gzwrite(outgz->gz_fd, data, len);
+	if (ret < 0) {
+		error_errno("gzwrite");
+		return -1;
+	} else if (ret < len) {
+		error("incomplete gzwrite");
+		return -1;
+	}
+
+	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, int fd)
+{
+	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, int64_t len)
+{
+	return -1;
+}
+
+static int callback_file_write(struct output_file *out, void *data, int len)
+{
+	int ret;
+	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, chunk;
+
+	if (skip_len % out->block_size) {
+		error("don't care size %llu 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, zero_len, count;
+	int ret;
+	unsigned int i;
+
+	/* 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)
+{
+	int ret;
+
+	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 = 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 *, int),
+		void *priv, unsigned int block_size, int64_t len, int gz, 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();
+	}
+
+	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;
+	int buffer_size;
+	char *ptr;
+
+	aligned_offset = offset & ~(4096 - 1);
+	aligned_diff = offset - aligned_offset;
+	buffer_size = len + aligned_diff;
+
+#ifndef USE_MINGW
+	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) {
+		return -errno;
+	}
+	ret = read_all(fd, data, len);
+	if (ret < 0) {
+		return ret;
+	}
+	ptr = data;
+#endif
+
+	ret = out->sparse_ops->write_data_chunk(out, len, ptr);
+
+#ifndef USE_MINGW
+	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
new file mode 100644
index 0000000..474c1fc
--- /dev/null
+++ b/libsparse/output_file.h
@@ -0,0 +1,41 @@
+/*
+ * 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.
+ */
+
+#ifndef _OUTPUT_FILE_H_
+#define _OUTPUT_FILE_H_
+
+#include <sparse/sparse.h>
+
+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 *, int),
+		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);
+
+#endif
diff --git a/libsparse/simg2img.c b/libsparse/simg2img.c
new file mode 100644
index 0000000..95e9b5b
--- /dev/null
+++ b/libsparse/simg2img.c
@@ -0,0 +1,89 @@
+/*
+ * 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;
+	int ret;
+	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);
+		}
+
+		lseek(out, SEEK_SET, 0);
+
+		ret = sparse_file_write(s, out, false, false, false);
+		if (ret < 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
new file mode 100644
index 0000000..5f9ccf6
--- /dev/null
+++ b/libsparse/simg2simg.c
@@ -0,0 +1,115 @@
+/*
+ * 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/simg_dump.py b/libsparse/simg_dump.py
new file mode 100755
index 0000000..6ece31d
--- /dev/null
+++ b/libsparse/simg_dump.py
@@ -0,0 +1,169 @@
+#! /usr/bin/env python
+
+# 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.
+
+from __future__ import print_function
+import getopt, posixpath, signal, struct, sys
+
+def usage(argv0):
+  print("""
+Usage: %s [-v] sparse_image_file ...
+ -v             verbose output
+""" % ( argv0 ))
+  sys.exit(2)
+
+def main():
+
+  signal.signal(signal.SIGPIPE, signal.SIG_DFL)
+
+  me = posixpath.basename(sys.argv[0])
+
+  # Parse the command line
+  verbose = 0			# -v
+  try:
+    opts, args = getopt.getopt(sys.argv[1:],
+                               "v",
+                               ["verbose"])
+  except getopt.GetoptError, e:
+    print(e)
+    usage(me)
+  for o, a in opts:
+    if o in ("-v", "--verbose"):
+      verbose += 1
+    else:
+      print("Unrecognized option \"%s\"" % (o))
+      usage(me)
+
+  if len(args) == 0:
+    print("No sparse_image_file specified")
+    usage(me)
+
+  for path in args:
+    FH = open(path, 'rb')
+    header_bin = FH.read(28)
+    header = struct.unpack("<I4H4I", header_bin)
+
+    magic = header[0]
+    major_version = header[1]
+    minor_version = header[2]
+    file_hdr_sz = header[3]
+    chunk_hdr_sz = header[4]
+    blk_sz = header[5]
+    total_blks = header[6]
+    total_chunks = header[7]
+    image_checksum = header[8]
+
+    if magic != 0xED26FF3A:
+      print("%s: %s: Magic should be 0xED26FF3A but is 0x%08X"
+            % (me, path, magic))
+      continue
+    if major_version != 1 or minor_version != 0:
+      print("%s: %s: I only know about version 1.0, but this is version %u.%u"
+            % (me, path, major_version, minor_version))
+      continue
+    if file_hdr_sz != 28:
+      print("%s: %s: The file header size was expected to be 28, but is %u."
+            % (me, path, file_hdr_sz))
+      continue
+    if chunk_hdr_sz != 12:
+      print("%s: %s: The chunk header size was expected to be 12, but is %u."
+            % (me, path, chunk_hdr_sz))
+      continue
+
+    print("%s: Total of %u %u-byte output blocks in %u input chunks."
+          % (path, total_blks, blk_sz, total_chunks))
+
+    if image_checksum != 0:
+      print("checksum=0x%08X" % (image_checksum))
+
+    if not verbose:
+      continue
+    print("            input_bytes      output_blocks")
+    print("chunk    offset     number  offset  number")
+    offset = 0
+    for i in xrange(1,total_chunks+1):
+      header_bin = FH.read(12)
+      header = struct.unpack("<2H2I", header_bin)
+      chunk_type = header[0]
+      reserved1 = header[1]
+      chunk_sz = header[2]
+      total_sz = header[3]
+      data_sz = total_sz - 12
+
+      print("%4u %10u %10u %7u %7u" % (i, FH.tell(), data_sz, offset, chunk_sz),
+            end=" ")
+
+      if chunk_type == 0xCAC1:
+        if data_sz != (chunk_sz * blk_sz):
+          print("Raw chunk input size (%u) does not match output size (%u)"
+                % (data_sz, chunk_sz * blk_sz))
+          break;
+        else:
+          print("Raw data", end="")
+          FH.read(data_sz)
+      elif chunk_type == 0xCAC2:
+        if data_sz != 4:
+          print("Fill chunk should have 4 bytes of fill, but this has %u"
+                % (data_sz), end="")
+          break;
+        else:
+          fill_bin = FH.read(4)
+          fill = struct.unpack("<I", fill_bin)
+          print("Fill with 0x%08X" % (fill))
+      elif chunk_type == 0xCAC3:
+        if data_sz != 0:
+          print("Don't care chunk input size is non-zero (%u)" % (data_sz))
+          break;
+        else:
+          print("Don't care", end="")
+      elif chunk_type == 0xCAC4:
+        if data_sz != 4:
+          print("CRC32 chunk should have 4 bytes of CRC, but this has %u"
+                % (data_sz), end="")
+          break;
+        else:
+          crc_bin = FH.read(4)
+          crc = struct.unpack("<I", crc)
+          print("Unverified CRC32 0x%08X" % (crc))
+      else:
+          print("Unknown chunk type 0x%04X" % (chunk_type), end="")
+          break;
+
+      if verbose > 1:
+        header = struct.unpack("<12B", header_bin)
+        print(" (%02X%02X %02X%02X %02X%02X%02X%02X %02X%02X%02X%02X)"
+              % (header[0], header[1], header[2], header[3],
+                 header[4], header[5], header[6], header[7],
+                 header[8], header[9], header[10], header[11]))
+      else:
+        print()
+
+      offset += chunk_sz
+
+    print("     %10u            %7u         End" % (FH.tell(), offset))
+
+    if total_blks != offset:
+      print("The header said we should have %u output blocks, but we saw %u"
+            % (total_blks, offset))
+
+    junk_len = len(FH.read())
+    if junk_len:
+      print("There were %u bytes of extra data at the end of the file."
+            % (junk_len))
+
+  sys.exit(0)
+
+if __name__ == "__main__":
+  main()
diff --git a/libsparse/sparse.c b/libsparse/sparse.c
new file mode 100644
index 0000000..189b4c0
--- /dev/null
+++ b/libsparse/sparse.c
@@ -0,0 +1,317 @@
+/*
+ * 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 "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 void sparse_file_write_block(struct output_file *out,
+		struct backed_block *bb)
+{
+	switch (backed_block_type(bb)) {
+	case BACKED_BLOCK_DATA:
+		write_data_chunk(out, backed_block_len(bb), backed_block_data(bb));
+		break;
+	case BACKED_BLOCK_FILE:
+		write_file_chunk(out, backed_block_len(bb),
+				backed_block_filename(bb), backed_block_file_offset(bb));
+		break;
+	case BACKED_BLOCK_FD:
+		write_fd_chunk(out, backed_block_len(bb),
+				backed_block_fd(bb), backed_block_file_offset(bb));
+		break;
+	case BACKED_BLOCK_FILL:
+		write_fill_chunk(out, backed_block_len(bb),
+				backed_block_fill_val(bb));
+		break;
+	}
+}
+
+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;
+
+	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);
+		}
+		sparse_file_write_block(out, bb);
+		last_block = backed_block_block(bb) +
+				DIV_ROUND_UP(backed_block_len(bb), s->block_size);
+	}
+
+	pad = s->len - 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, int 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;
+}
+
+static int out_counter_write(void *priv, const void *data, int 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;
+}
+
+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;
+	int64_t file_len = 0;
+
+	/*
+	 * overhead is sparse file header, initial skip chunk, split chunk, end
+	 * skip chunk, and crc chunk.
+	 */
+	int overhead = sizeof(sparse_header_t) + 4 * 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;
+		/* will call out_counter_write to update count */
+		sparse_file_write_block(out_counter, bb);
+		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
+			 */
+			if (!last_bb || (len - file_len > (len / 8))) {
+				backed_block_split(from->backed_block_list, bb, len - file_len);
+				last_bb = bb;
+			}
+			goto out;
+		}
+		file_len += count;
+		last_bb = bb;
+	}
+
+out:
+	backed_block_list_move(from->backed_block_list,
+		to->backed_block_list, start, last_bb);
+
+	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;
+	unsigned int overhead;
+	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
new file mode 100644
index 0000000..38bfe4a
--- /dev/null
+++ b/libsparse/sparse_crc32.c
@@ -0,0 +1,111 @@
+/*-
+ *  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.h b/libsparse/sparse_crc32.h
new file mode 100644
index 0000000..cad8a86
--- /dev/null
+++ b/libsparse/sparse_crc32.h
@@ -0,0 +1,20 @@
+/*
+ * 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 <stdint.h>
+
+uint32_t sparse_crc32(uint32_t crc, const void *buf, size_t size);
+
diff --git a/libsparse/sparse_defs.h b/libsparse/sparse_defs.h
new file mode 100644
index 0000000..b99cfd5
--- /dev/null
+++ b/libsparse/sparse_defs.h
@@ -0,0 +1,49 @@
+/*
+ * 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.
+ */
+
+#ifndef _LIBSPARSE_SPARSE_DEFS_
+#define _LIBSPARSE_SPARSE_DEFS_
+
+#include <errno.h>
+#include <stdio.h>
+
+#define __le64 u64
+#define __le32 u32
+#define __le16 u16
+
+#define __be64 u64
+#define __be32 u32
+#define __be16 u16
+
+#define __u64 u64
+#define __u32 u32
+#define __u16 u16
+#define __u8 u8
+
+typedef unsigned long long u64;
+typedef signed long long s64;
+typedef unsigned int u32;
+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 ALIGN_DOWN(x, y) ((y) * ((x) / (y)))
+
+#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.c
new file mode 100644
index 0000000..0f392ad
--- /dev/null
+++ b/libsparse/sparse_err.c
@@ -0,0 +1,33 @@
+/*
+ * 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 <sparse/sparse.h>
+
+#include <stdarg.h>
+#include <stdio.h>
+#include <unistd.h>
+
+void sparse_default_print(const char *fmt, ...)
+{
+	va_list 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;
diff --git a/libsparse/sparse_file.h b/libsparse/sparse_file.h
new file mode 100644
index 0000000..91a12e6
--- /dev/null
+++ b/libsparse/sparse_file.h
@@ -0,0 +1,32 @@
+/*
+ * 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.
+ */
+
+#ifndef _LIBSPARSE_SPARSE_FILE_H_
+#define _LIBSPARSE_SPARSE_FILE_H_
+
+#include <sparse/sparse.h>
+
+struct sparse_file {
+	unsigned int block_size;
+	int64_t len;
+	bool verbose;
+
+	struct backed_block_list *backed_block_list;
+	struct output_file *out;
+};
+
+
+#endif /* _LIBSPARSE_SPARSE_FILE_H_ */
diff --git a/libsparse/sparse_format.h b/libsparse/sparse_format.h
new file mode 100644
index 0000000..c41f12a
--- /dev/null
+++ b/libsparse/sparse_format.h
@@ -0,0 +1,55 @@
+/*
+ * 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.
+ */
+
+#ifndef _LIBSPARSE_SPARSE_FORMAT_H_
+#define _LIBSPARSE_SPARSE_FORMAT_H_
+#include "sparse_defs.h"
+
+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 */
+} sparse_header_t;
+
+#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
+
+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 */
+} chunk_header_t;
+
+/* Following a Raw or Fill or CRC32 chunk is data.
+ *  For a Raw chunk, it's the data in chunk_sz * blk_sz.
+ *  For a Fill chunk, it's 4 bytes of the fill data.
+ *  For a CRC32 chunk, it's 4 bytes of CRC32
+ */
+
+#endif
diff --git a/libsparse/sparse_read.c b/libsparse/sparse_read.c
new file mode 100644
index 0000000..704bcfa
--- /dev/null
+++ b/libsparse/sparse_read.c
@@ -0,0 +1,509 @@
+/*
+ * 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 _GNU_SOURCE
+#define _FILE_OFFSET_BITS 64
+#define _LARGEFILE64_SOURCE 1
+
+#include <fcntl.h>
+#include <stdarg.h>
+#include <stdbool.h>
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sparse/sparse.h>
+
+#include "sparse_crc32.h"
+#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 CHUNK_HEADER_LEN (sizeof(chunk_header_t))
+
+#define COPY_BUF_SIZE (1024U*1024U)
+static char *copybuf;
+
+#define min(a, b) \
+	({ typeof(a) _a = (a); typeof(b) _b = (b); (_a < _b) ? _a : _b; })
+
+static void verbose_error(bool verbose, int err, const char *fmt, ...)
+{
+	char *s = "";
+	char *at = "";
+	if (fmt) {
+		va_list argp;
+		int size;
+
+		va_start(argp, fmt);
+		size = vsnprintf(NULL, 0, fmt, argp);
+		va_end(argp);
+
+		if (size < 0) {
+			return;
+		}
+
+		at = malloc(size + 1);
+		if (at == NULL) {
+			return;
+		}
+
+		va_start(argp, fmt);
+		vsnprintf(at, size, fmt, argp);
+		va_end(argp);
+		at[size] = 0;
+		s = " at ";
+	}
+	if (verbose) {
+#ifndef USE_MINGW
+		if (err == -EOVERFLOW) {
+			sparse_print_verbose("EOF while reading file%s%s\n", s, at);
+		} else
+#endif
+		if (err == -EINVAL) {
+			sparse_print_verbose("Invalid sparse file format%s%s\n", s, at);
+		} else if (err == -ENOMEM) {
+			sparse_print_verbose("Failed allocation while reading file%s%s\n",
+					s, at);
+		} else {
+			sparse_print_verbose("Unknown error %d%s%s\n", err, s, at);
+		}
+	}
+	if (fmt) {
+		free(at);
+	}
+}
+
+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;
+	unsigned int len = blocks * s->block_size;
+
+	if (chunk_size % s->block_size != 0) {
+		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;
+	}
+
+	if (crc32) {
+		while (len) {
+			chunk = 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);
+	}
+
+	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;
+
+	if (chunk_size != sizeof(fill_val)) {
+		return -EINVAL;
+	}
+
+	ret = read_all(fd, &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;
+	}
+
+	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 = min(len, COPY_BUF_SIZE);
+			*crc32 = sparse_crc32(*crc32, copybuf, chunk);
+			len -= chunk;
+		}
+	}
+
+	return 0;
+}
+
+static int process_skip_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;
+
+	if (chunk_size != 0) {
+		return -EINVAL;
+	}
+
+	if (crc32) {
+		memset(copybuf, 0, COPY_BUF_SIZE);
+
+		while (len) {
+			chunk = min(len, COPY_BUF_SIZE);
+			*crc32 = sparse_crc32(*crc32, copybuf, chunk);
+			len -= chunk;
+		}
+	}
+
+	return 0;
+}
+
+static int process_crc32_chunk(int fd, unsigned int chunk_size, uint32_t crc32)
+{
+	uint32_t file_crc32;
+	int ret;
+
+	if (chunk_size != sizeof(file_crc32)) {
+		return -EINVAL;
+	}
+
+	ret = read_all(fd, &file_crc32, sizeof(file_crc32));
+	if (ret < 0) {
+		return ret;
+	}
+
+	if (file_crc32 != crc32) {
+		return -EINVAL;
+	}
+
+	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;
+
+	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 %lld", 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 %lld", 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 %lld", 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 %lld",
+						offset);
+				return ret;
+			}
+			return 0;
+		default:
+			verbose_error(s->verbose, -EINVAL, "unknown block %04X at %lld",
+					chunk_header->chunk_type, offset);
+	}
+
+	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;
+
+	if (!copybuf) {
+		copybuf = malloc(COPY_BUF_SIZE);
+	}
+
+	if (!copybuf) {
+		return -ENOMEM;
+	}
+
+	if (crc) {
+		crc_ptr = &crc32;
+	}
+
+	ret = read_all(fd, &sparse_header, sizeof(sparse_header));
+	if (ret < 0) {
+		return ret;
+	}
+
+	if (sparse_header.magic != SPARSE_HEADER_MAGIC) {
+		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.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);
+	}
+
+	for (i = 0; i < sparse_header.total_chunks; i++) {
+		ret = read_all(fd, &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);
+		}
+
+		offset = lseek64(fd, 0, SEEK_CUR);
+
+		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;
+	}
+
+	if (sparse_header.total_blks != cur_block) {
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static int sparse_file_read_normal(struct sparse_file *s, int fd)
+{
+	int ret;
+	uint32_t *buf = malloc(s->block_size);
+	unsigned int block = 0;
+	int64_t remain = s->len;
+	int64_t offset = 0;
+	unsigned int to_read;
+	char *ptr;
+	unsigned int i;
+	bool sparse_block;
+
+	if (!buf) {
+		return -ENOMEM;
+	}
+
+	while (remain > 0) {
+		to_read = min(remain, s->block_size);
+		ret = read_all(fd, buf, to_read);
+		if (ret < 0) {
+			error("failed to read sparse file");
+			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 (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++;
+	}
+
+	return 0;
+}
+
+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);
+	}
+}
+
+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;
+}
+
+struct sparse_file *sparse_file_import_auto(int fd, bool crc)
+{
+	struct sparse_file *s;
+	int64_t len;
+	int ret;
+
+	s = sparse_file_import(fd, true, 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;
+}