From: Linus Torvalds Date: Sun, 26 Jun 2005 15:40:08 +0000 (-0700) Subject: Fix object packing/unpacking. X-Git-Tag: v0.99~171 X-Git-Url: https://git.verplant.org/?a=commitdiff_plain;h=c4fb06c0d04f433ab71d84674ebfe18cda162369;p=git.git Fix object packing/unpacking. This actually successfully packed and unpacked a git archive down to 1.3MB (17MB unpacked). Right now unpacking is way too noisy, lots of debug messages left. --- diff --git a/pack-objects.c b/pack-objects.c index 3900df3a..aa6cb6d3 100644 --- a/pack-objects.c +++ b/pack-objects.c @@ -96,7 +96,7 @@ static unsigned long write_object(FILE *f, struct object_entry *entry) unsigned long size; char type[10]; void *buf = read_sha1_file(entry->sha1, type, &size); - char header[21]; + char header[25]; unsigned hdrlen, datalen; if (!buf) @@ -110,16 +110,16 @@ static unsigned long write_object(FILE *f, struct object_entry *entry) * instead. */ header[0] = ".CTB"[entry->type]; - datalen = htonl(size); - memcpy(header+1, &datalen, 4); hdrlen = 5; if (entry->delta) { header[0] = 'D'; - memcpy(header+1, entry->delta, 20); + memcpy(header+5, entry->delta, 20); buf = delta_against(buf, size, entry); size = entry->delta_size; - hdrlen = 21; + hdrlen = 25; } + datalen = htonl(size); + memcpy(header+1, &datalen, 4); fwrite(header, hdrlen, 1, f); datalen = fwrite_compressed(buf, size, f); free(buf); diff --git a/unpack-objects.c b/unpack-objects.c index a7b8df07..a62eeb43 100644 --- a/unpack-objects.c +++ b/unpack-objects.c @@ -88,26 +88,26 @@ static int check_index(void) } static int unpack_non_delta_entry(struct pack_entry *entry, - unsigned char *pack) + int kind, + unsigned char *data, + unsigned long size, + unsigned long left) { - int st, kind; - unsigned long size; + int st; z_stream stream; char *buffer; unsigned char sha1[20]; char *type_s; - unsigned long offset = ntohl(entry->offset); - kind = pack[0]; - size = (pack[1] << 24) + (pack[2] << 16) + (pack[3] << 8) + pack[4]; printf("%s %c %lu\n", sha1_to_hex(entry->sha1), kind, size); - pack += 5; + if (dry_run) + return 0; buffer = xmalloc(size + 1); buffer[size] = 0; memset(&stream, 0, sizeof(stream)); - stream.next_in = pack; - stream.avail_in = pack_size - offset; /* sheesh. */ + stream.next_in = data; + stream.avail_in = left; stream.next_out = buffer; stream.avail_out = size; @@ -148,14 +148,15 @@ static int find_pack_entry(unsigned char *sha1, struct pack_entry **ent) do { int mi = (lo + hi) / 2; int cmp = memcmp(index + 24 * mi + 4, sha1, 20); +printf("lo=%d mi=%d hi=%d cmp=%d\n", lo, mi, hi, cmp); if (!cmp) { *ent = index + 24 * mi; return 1; } - if (cmp < 0) + if (cmp > 0) hi = mi; else - lo = mi; + lo = mi+1; } while (lo < hi); return 0; } @@ -163,70 +164,55 @@ static int find_pack_entry(unsigned char *sha1, struct pack_entry **ent) /* forward declaration for a mutually recursive function */ static void unpack_entry(struct pack_entry *); -static int unpack_delta_entry(struct pack_entry *entry, unsigned char *pack) +static int unpack_delta_entry(struct pack_entry *entry, + unsigned char *base_sha1, + unsigned long delta_size, + unsigned long left) { - void *delta_data, *result, *base; - unsigned long delta_alloc, delta_size, result_size, base_size; + void *data, *delta_data, *result, *base; + unsigned long data_size, result_size, base_size; z_stream stream; int st; char type[20]; unsigned char sha1[20]; - printf("%s D", sha1_to_hex(entry->sha1)); - printf(" %s\n", sha1_to_hex(pack+1)); + if (left < 20) + die("truncated pack file"); + data = base_sha1 + 20; + data_size = left - 20; + printf("%s D %lu", sha1_to_hex(entry->sha1), delta_size); + printf(" %s\n", sha1_to_hex(base_sha1)); + + if (dry_run) + return 0; - /* pack+1 is the base sha1, unless we have it, we need to + /* pack+5 is the base sha1, unless we have it, we need to * unpack it first. */ - if (!has_sha1_file(pack+1)) { + if (!has_sha1_file(base_sha1)) { struct pack_entry *base; - if (!find_pack_entry(pack+1, &base)) + if (!find_pack_entry(base_sha1, &base)) die("cannot find delta-pack base object"); unpack_entry(base); } - - /* pack+1 thru pack+20 is the base sha1 and - * pack+21 thru unknown number is the delta data. - * we do not even have size of the delta data uncompressed. - * sheesh! - */ - delta_alloc = 1024; - delta_data = xmalloc(delta_alloc); + delta_data = xmalloc(delta_size); memset(&stream, 0, sizeof(stream)); - stream.next_in = pack + 21; - stream.avail_in = pack_size - ntohl(entry->offset); /* sheesh. */ + stream.next_in = data; + stream.avail_in = data_size; stream.next_out = delta_data; - stream.avail_out = delta_alloc; - delta_size = 0; + stream.avail_out = delta_size; inflateInit(&stream); - while (1) { - st = inflate(&stream, Z_FINISH); - if (st == Z_STREAM_END) { - delta_size = stream.total_out; - break; - } - if (st < 0) - break; - - if (delta_alloc <= stream.total_out) { - delta_alloc = (delta_alloc +1024) * 3 / 2; - delta_data = xrealloc(delta_data, delta_alloc); - stream.next_out = delta_data + stream.total_out; - stream.avail_out = delta_alloc - stream.total_out; - } - } + st = inflate(&stream, Z_FINISH); inflateEnd(&stream); - if (st != Z_STREAM_END) { - free(delta_data); - return -1; - } + if ((st != Z_STREAM_END) || stream.total_out != delta_size) + die("delta data unpack failed"); - base = read_sha1_file(pack+1, type, &base_size); + base = read_sha1_file(base_sha1, type, &base_size); if (!base) - die("failed to read delta-pack base object"); + die("failed to read delta-pack base object %s", sha1_to_hex(base_sha1)); result = patch_delta(base, base_size, delta_data, delta_size, &result_size); @@ -246,7 +232,7 @@ static int unpack_delta_entry(struct pack_entry *entry, unsigned char *pack) static void unpack_entry(struct pack_entry *entry) { - unsigned long offset; + unsigned long offset, size, left; unsigned char *pack; /* Have we done this one already due to deltas based on it? */ @@ -257,13 +243,14 @@ static void unpack_entry(struct pack_entry *entry) if (offset > pack_size - 5) die("object offset outside of pack file"); pack = pack_base + offset; - offset = pack_size - offset; + size = (pack[1] << 24) + (pack[2] << 16) + (pack[3] << 8) + pack[4]; + left = pack_size - offset - 5; switch (*pack) { case 'C': case 'T': case 'B': - unpack_non_delta_entry(entry, pack); + unpack_non_delta_entry(entry, *pack, pack+5, size, left); break; case 'D': - unpack_delta_entry(entry, pack); + unpack_delta_entry(entry, pack+5, size, left); break; default: die("corrupted pack file");