binary diff: further updates.
This updates the user interface and generated diff data format.
* "diff --binary" is used to signal that we want an e-mailable
binary patch. It implies --full-index and -p.
* "apply --allow-binary-replacement" acquired a short synonym
"apply --binary".
* After the "GIT binary patch\n" header line there is a token
to record which binary patch mechanism was used, so that we
can extend it later. Currently there are two mechanisms
defined: "literal" and "delta". The former records the
deflated postimage and the latter records the deflated delta
from the preimage to postimage.
For purely implementation convenience, I added the deflated
length after these "literal/delta" tokens (otherwise the
decoding side needs to guess and reallocate the buffer while
inflating). Improvement patches are very welcomed.
Signed-off-by: Junio C Hamano <junkio@cox.net>
diff --git a/apply.c b/apply.c
index e37c4eb..1b93aab 100644
--- a/apply.c
+++ b/apply.c
@@ -114,6 +114,9 @@
char *new_name, *old_name, *def_name;
unsigned int old_mode, new_mode;
int is_rename, is_copy, is_new, is_delete, is_binary;
+#define BINARY_DELTA_DEFLATED 1
+#define BINARY_LITERAL_DEFLATED 2
+ unsigned long deflate_origlen;
int lines_added, lines_deleted;
int score;
struct fragment *fragments;
@@ -969,9 +972,11 @@
static int parse_binary(char *buffer, unsigned long size, struct patch *patch)
{
- /* We have read "GIT binary patch\n"; what follows is a
- * sequence of 'length-byte' followed by base-85 encoded
- * delta data.
+ /* We have read "GIT binary patch\n"; what follows is a line
+ * that says the patch method (currently, either "deflated
+ * literal" or "deflated delta") and the length of data before
+ * deflating; a sequence of 'length-byte' followed by base-85
+ * encoded data follows.
*
* Each 5-byte sequence of base-85 encodes up to 4 bytes,
* and we would limit the patch line to 66 characters,
@@ -982,11 +987,27 @@
*/
int llen, used;
struct fragment *fragment;
- char *delta = NULL;
+ char *data = NULL;
- patch->is_binary = 1;
patch->fragments = fragment = xcalloc(1, sizeof(*fragment));
- used = 0;
+
+ /* Grab the type of patch */
+ llen = linelen(buffer, size);
+ used = llen;
+ linenr++;
+
+ if (!strncmp(buffer, "delta ", 6)) {
+ patch->is_binary = BINARY_DELTA_DEFLATED;
+ patch->deflate_origlen = strtoul(buffer + 6, NULL, 10);
+ }
+ else if (!strncmp(buffer, "literal ", 8)) {
+ patch->is_binary = BINARY_LITERAL_DEFLATED;
+ patch->deflate_origlen = strtoul(buffer + 8, NULL, 10);
+ }
+ else
+ return error("unrecognized binary patch at line %d: %.*s",
+ linenr-1, llen-1, buffer);
+ buffer += llen;
while (1) {
int byte_length, max_byte_length, newsize;
llen = linelen(buffer, size);
@@ -1015,8 +1036,8 @@
byte_length <= max_byte_length - 4)
goto corrupt;
newsize = fragment->size + byte_length;
- delta = xrealloc(delta, newsize);
- if (decode_85(delta + fragment->size,
+ data = xrealloc(data, newsize);
+ if (decode_85(data + fragment->size,
buffer + 1,
byte_length))
goto corrupt;
@@ -1024,7 +1045,7 @@
buffer += llen;
size -= llen;
}
- fragment->patch = delta;
+ fragment->patch = data;
return used;
corrupt:
return error("corrupt binary patch at line %d: %.*s",
@@ -1425,6 +1446,61 @@
return offset;
}
+static char *inflate_it(const void *data, unsigned long size,
+ unsigned long inflated_size)
+{
+ z_stream stream;
+ void *out;
+ int st;
+
+ memset(&stream, 0, sizeof(stream));
+
+ stream.next_in = (unsigned char *)data;
+ stream.avail_in = size;
+ stream.next_out = out = xmalloc(inflated_size);
+ stream.avail_out = inflated_size;
+ inflateInit(&stream);
+ st = inflate(&stream, Z_FINISH);
+ if ((st != Z_STREAM_END) || stream.total_out != inflated_size) {
+ free(out);
+ return NULL;
+ }
+ return out;
+}
+
+static int apply_binary_fragment(struct buffer_desc *desc, struct patch *patch)
+{
+ unsigned long dst_size;
+ struct fragment *fragment = patch->fragments;
+ void *data;
+ void *result;
+
+ data = inflate_it(fragment->patch, fragment->size,
+ patch->deflate_origlen);
+ if (!data)
+ return error("corrupt patch data");
+ switch (patch->is_binary) {
+ case BINARY_DELTA_DEFLATED:
+ result = patch_delta(desc->buffer, desc->size,
+ data,
+ patch->deflate_origlen,
+ &dst_size);
+ free(desc->buffer);
+ desc->buffer = result;
+ free(data);
+ break;
+ case BINARY_LITERAL_DEFLATED:
+ free(desc->buffer);
+ desc->buffer = data;
+ dst_size = patch->deflate_origlen;
+ break;
+ }
+ if (!desc->buffer)
+ return -1;
+ desc->size = desc->alloc = dst_size;
+ return 0;
+}
+
static int apply_binary(struct buffer_desc *desc, struct patch *patch)
{
const char *name = patch->old_name ? patch->old_name : patch->new_name;
@@ -1466,18 +1542,20 @@
"'%s' but it is not empty", name);
}
- if (desc->buffer) {
+ get_sha1_hex(patch->new_sha1_prefix, sha1);
+ if (!memcmp(sha1, null_sha1, 20)) {
free(desc->buffer);
desc->alloc = desc->size = 0;
- }
- get_sha1_hex(patch->new_sha1_prefix, sha1);
- if (!memcmp(sha1, null_sha1, 20))
+ desc->buffer = NULL;
return 0; /* deletion patch */
+ }
if (has_sha1_file(sha1)) {
+ /* We already have the postimage */
char type[10];
unsigned long size;
+ free(desc->buffer);
desc->buffer = read_sha1_file(sha1, type, &size);
if (!desc->buffer)
return error("the necessary postimage %s for "
@@ -1486,28 +1564,13 @@
desc->alloc = desc->size = size;
}
else {
- char type[10];
- unsigned long src_size, dst_size;
- void *src;
-
- get_sha1_hex(patch->old_sha1_prefix, sha1);
- src = read_sha1_file(sha1, type, &src_size);
- if (!src)
- return error("the necessary preimage %s for "
- "'%s' cannot be read",
- patch->old_sha1_prefix, name);
-
- /* patch->fragment->patch has the delta data and
- * we should apply it to the preimage.
+ /* We have verified desc matches the preimage;
+ * apply the patch data to it, which is stored
+ * in the patch->fragments->{patch,size}.
*/
- desc->buffer = patch_delta(src, src_size,
- (void*) patch->fragments->patch,
- patch->fragments->size,
- &dst_size);
- if (!desc->buffer)
+ if (apply_binary_fragment(desc, patch))
return error("binary patch does not apply to '%s'",
name);
- desc->size = desc->alloc = dst_size;
/* verify that the result matches */
write_sha1_file_prepare(desc->buffer, desc->size, blob_type,
@@ -2102,7 +2165,8 @@
diffstat = 1;
continue;
}
- if (!strcmp(arg, "--allow-binary-replacement")) {
+ if (!strcmp(arg, "--allow-binary-replacement") ||
+ !strcmp(arg, "--binary")) {
allow_binary_replacement = 1;
continue;
}
diff --git a/base85.c b/base85.c
new file mode 100644
index 0000000..b97f7f9
--- /dev/null
+++ b/base85.c
@@ -0,0 +1,134 @@
+#include "cache.h"
+
+#undef DEBUG_85
+
+#ifdef DEBUG_85
+#define say(a) fprintf(stderr, a)
+#define say1(a,b) fprintf(stderr, a, b)
+#define say2(a,b,c) fprintf(stderr, a, b, c)
+#else
+#define say(a) do {} while(0)
+#define say1(a,b) do {} while(0)
+#define say2(a,b,c) do {} while(0)
+#endif
+
+static const char en85[] = {
+ '0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+ 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J',
+ 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R', 'S', 'T',
+ 'U', 'V', 'W', 'X', 'Y', 'Z',
+ 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
+ 'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't',
+ 'u', 'v', 'w', 'x', 'y', 'z',
+ '!', '#', '$', '%', '&', '(', ')', '*', '+', '-',
+ ';', '<', '=', '>', '?', '@', '^', '_', '`', '{',
+ '|', '}', '~'
+};
+
+static char de85[256];
+static void prep_base85(void)
+{
+ int i;
+ if (de85['Z'])
+ return;
+ for (i = 0; i < ARRAY_SIZE(en85); i++) {
+ int ch = en85[i];
+ de85[ch] = i + 1;
+ }
+}
+
+int decode_85(char *dst, char *buffer, int len)
+{
+ prep_base85();
+
+ say2("decode 85 <%.*s>", len/4*5, buffer);
+ while (len) {
+ unsigned acc = 0;
+ int cnt;
+ for (cnt = 0; cnt < 5; cnt++, buffer++) {
+ int ch = *((unsigned char *)buffer);
+ int de = de85[ch];
+ if (!de)
+ return error("invalid base85 alphabet %c", ch);
+ de--;
+ if (cnt == 4) {
+ /*
+ * Detect overflow. The largest
+ * 5-letter possible is "|NsC0" to
+ * encode 0xffffffff, and "|NsC" gives
+ * 0x03030303 at this point (i.e.
+ * 0xffffffff = 0x03030303 * 85).
+ */
+ if (0x03030303 < acc ||
+ (0x03030303 == acc && de))
+ error("invalid base85 sequence %.5s",
+ buffer-3);
+ }
+ acc = acc * 85 + de;
+ say1(" <%08x>", acc);
+ }
+ say1(" %08x", acc);
+ for (cnt = 0; cnt < 4 && len; cnt++, len--) {
+ *dst++ = (acc >> 24) & 0xff;
+ acc = acc << 8;
+ }
+ }
+ say("\n");
+
+ return 0;
+}
+
+void encode_85(char *buf, unsigned char *data, int bytes)
+{
+ prep_base85();
+
+ say("encode 85");
+ while (bytes) {
+ unsigned acc = 0;
+ int cnt;
+ for (cnt = 0; cnt < 4 && bytes; cnt++, bytes--) {
+ int ch = *data++;
+ acc |= ch << ((3-cnt)*8);
+ }
+ say1(" %08x", acc);
+ for (cnt = 0; cnt < 5; cnt++) {
+ int val = acc % 85;
+ acc /= 85;
+ buf[4-cnt] = en85[val];
+ }
+ buf += 5;
+ }
+ say("\n");
+
+ *buf = 0;
+}
+
+#ifdef DEBUG_85
+int main(int ac, char **av)
+{
+ char buf[1024];
+
+ if (!strcmp(av[1], "-e")) {
+ int len = strlen(av[2]);
+ encode_85(buf, av[2], len);
+ if (len <= 26) len = len + 'A' - 1;
+ else len = len + 'a' - 26 + 1;
+ printf("encoded: %c%s\n", len, buf);
+ return 0;
+ }
+ if (!strcmp(av[1], "-d")) {
+ int len = *av[2];
+ if ('A' <= len && len <= 'Z') len = len - 'A' + 1;
+ else len = len - 'a' + 26 + 1;
+ decode_85(buf, av[2]+1, len);
+ printf("decoded: %.*s\n", len, buf);
+ return 0;
+ }
+ if (!strcmp(av[1], "-t")) {
+ char t[4] = { -1,-1,-1,-1 };
+ encode_85(buf, t, 4);
+ printf("encoded: D%s\n", buf);
+ return 0;
+ }
+}
+#endif
diff --git a/cache.h b/cache.h
index 2f32f3d..4b7a439 100644
--- a/cache.h
+++ b/cache.h
@@ -365,5 +365,6 @@
/* base85 */
int decode_85(char *dst, char *line, int linelen);
+void encode_85(char *buf, unsigned char *data, int bytes);
#endif /* CACHE_H */
diff --git a/diff.c b/diff.c
index b14d897..bfe54c3 100644
--- a/diff.c
+++ b/diff.c
@@ -392,78 +392,78 @@
total_files, adds, dels);
}
-static void *encode_delta_size(void *data, unsigned long size)
+static unsigned char *deflate_it(char *data,
+ unsigned long size,
+ unsigned long *result_size)
{
- unsigned char *cp = data;
- *cp++ = size;
- size >>= 7;
- while (size) {
- cp[-1] |= 0x80;
- *cp++ = size;
- size >>= 7;
- }
- return cp;
-}
+ int bound;
+ unsigned char *deflated;
+ z_stream stream;
-static void *safe_diff_delta(const unsigned char *src, unsigned long src_size,
- const unsigned char *dst, unsigned long dst_size,
- unsigned long *delta_size)
-{
- unsigned long bufsize;
- unsigned char *data;
- unsigned char *cp;
+ memset(&stream, 0, sizeof(stream));
+ deflateInit(&stream, Z_BEST_COMPRESSION);
+ bound = deflateBound(&stream, size);
+ deflated = xmalloc(bound);
+ stream.next_out = deflated;
+ stream.avail_out = bound;
- if (src_size && dst_size)
- return diff_delta(src, src_size, dst, dst_size, delta_size, 0);
-
- /* diff-delta does not like to do delta with empty, so
- * we do that by hand here. Sigh...
- */
-
- if (!src_size)
- /* literal copy can be done only 127-byte at a time.
- */
- bufsize = dst_size + (dst_size / 127) + 40;
- else
- bufsize = 40;
- data = xmalloc(bufsize);
- cp = encode_delta_size(data, src_size);
- cp = encode_delta_size(cp, dst_size);
-
- if (dst_size) {
- /* copy out literally */
- while (dst_size) {
- int sz = (127 < dst_size) ? 127 : dst_size;
- *cp++ = sz;
- dst_size -= sz;
- while (sz) {
- *cp++ = *dst++;
- sz--;
- }
- }
- }
- *delta_size = (cp - data);
- return data;
+ stream.next_in = (unsigned char *)data;
+ stream.avail_in = size;
+ while (deflate(&stream, Z_FINISH) == Z_OK)
+ ; /* nothing */
+ deflateEnd(&stream);
+ *result_size = stream.total_out;
+ return deflated;
}
static void emit_binary_diff(mmfile_t *one, mmfile_t *two)
{
- void *delta, *cp;
+ void *cp;
+ void *delta;
+ void *deflated;
+ void *data;
+ unsigned long orig_size;
unsigned long delta_size;
+ unsigned long deflate_size;
+ unsigned long data_size;
printf("GIT binary patch\n");
- delta = safe_diff_delta(one->ptr, one->size,
- two->ptr, two->size,
- &delta_size);
- if (!delta)
- die("unable to generate binary diff");
+ /* We could do deflated delta, or we could do just deflated two,
+ * whichever is smaller.
+ */
+ delta = NULL;
+ deflated = deflate_it(two->ptr, two->size, &deflate_size);
+ if (one->size && two->size) {
+ delta = diff_delta(one->ptr, one->size,
+ two->ptr, two->size,
+ &delta_size, deflate_size);
+ if (delta) {
+ void *to_free = delta;
+ orig_size = delta_size;
+ delta = deflate_it(delta, delta_size, &delta_size);
+ free(to_free);
+ }
+ }
- /* emit delta encoded in base85 */
- cp = delta;
- while (delta_size) {
- int bytes = (52 < delta_size) ? 52 : delta_size;
+ if (delta && delta_size < deflate_size) {
+ printf("delta %lu\n", orig_size);
+ free(deflated);
+ data = delta;
+ data_size = delta_size;
+ }
+ else {
+ printf("literal %lu\n", two->size);
+ free(delta);
+ data = deflated;
+ data_size = deflate_size;
+ }
+
+ /* emit data encoded in base85 */
+ cp = data;
+ while (data_size) {
+ int bytes = (52 < data_size) ? 52 : data_size;
char line[70];
- delta_size -= bytes;
+ data_size -= bytes;
if (bytes <= 26)
line[0] = bytes + 'A' - 1;
else
@@ -473,7 +473,7 @@
puts(line);
}
printf("\n");
- free(delta);
+ free(data);
}
#define FIRST_FEW_BYTES 8000
@@ -538,7 +538,11 @@
die("unable to read files to diff");
if (mmfile_is_binary(&mf1) || mmfile_is_binary(&mf2)) {
- if (o->full_index)
+ /* Quite common confusing case */
+ if (mf1.size == mf2.size &&
+ !memcmp(mf1.ptr, mf2.ptr, mf1.size))
+ goto free_ab_and_return;
+ if (o->binary)
emit_binary_diff(&mf1, &mf2);
else
printf("Binary files %s and %s differ\n",
@@ -1239,6 +1243,10 @@
options->rename_limit = strtoul(arg+2, NULL, 10);
else if (!strcmp(arg, "--full-index"))
options->full_index = 1;
+ else if (!strcmp(arg, "--binary")) {
+ options->output_format = DIFF_FORMAT_PATCH;
+ options->full_index = options->binary = 1;
+ }
else if (!strcmp(arg, "--name-only"))
options->output_format = DIFF_FORMAT_NAME;
else if (!strcmp(arg, "--name-status"))
diff --git a/diff.h b/diff.h
index b3b2c4d..d052608 100644
--- a/diff.h
+++ b/diff.h
@@ -28,6 +28,7 @@
with_raw:1,
with_stat:1,
tree_in_recursive:1,
+ binary:1,
full_index:1,
silent_on_remove:1,
find_copies_harder:1;
