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Change pack file format. Hopefully for the last time.

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This also adds a header with a signature, version info, and the number
of objects to the pack file.  It also encodes the file length and type
more efficiently.
This commit is contained in:
Linus Torvalds
2005-06-28 14:21:02 -07:00
parent d22b9290ab
commit a733cb606f
4 changed files with 175 additions and 74 deletions
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75
sha1_file.c
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@ -10,6 +10,7 @@
#include <dirent.h>
#include "cache.h"
#include "delta.h"
#include "pack.h"
#ifndef O_NOATIME
#if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
@ -665,37 +666,60 @@ static int packed_delta_info(unsigned char *base_sha1,
return 0;
}
static unsigned long unpack_object_header(struct packed_git *p, unsigned long offset,
enum object_type *type, unsigned long *sizep)
{
unsigned char *pack, c;
unsigned long size;
if (offset >= p->pack_size)
die("object offset outside of pack file");
pack = p->pack_base + offset;
c = *pack++;
offset++;
*type = (c >> 4) & 7;
size = c & 15;
while (c & 0x80) {
if (offset >= p->pack_size)
die("object offset outside of pack file");
c = *pack++;
offset++;
size = (size << 7) | (c & 0x7f);
}
*sizep = size;
return offset;
}
static int packed_object_info(struct pack_entry *entry,
char *type, unsigned long *sizep)
{
struct packed_git *p = entry->p;
unsigned long offset, size, left;
unsigned char *pack;
offset = entry->offset;
if (p->pack_size - 5 < offset)
die("object offset outside of pack file");
enum object_type kind;
if (use_packed_git(p))
die("cannot map packed file");
offset = unpack_object_header(p, entry->offset, &kind, &size);
pack = p->pack_base + offset;
size = (pack[1] << 24) + (pack[2] << 16) + (pack[3] << 8) + pack[4];
left = p->pack_size - offset - 5;
switch (*pack) {
case 'D':
return packed_delta_info(pack+5, size, left, type, sizep);
left = p->pack_size - offset;
switch (kind) {
case OBJ_DELTA:
return packed_delta_info(pack, size, left, type, sizep);
break;
case 'C':
case OBJ_COMMIT:
strcpy(type, "commit");
break;
case 'T':
case OBJ_TREE:
strcpy(type, "tree");
break;
case 'B':
case OBJ_BLOB:
strcpy(type, "blob");
break;
case 'G':
case OBJ_TAG:
strcpy(type, "tag");
break;
default:
@ -787,37 +811,34 @@ static void *unpack_entry(struct pack_entry *entry,
struct packed_git *p = entry->p;
unsigned long offset, size, left;
unsigned char *pack;
offset = entry->offset;
if (p->pack_size - 5 < offset)
die("object offset outside of pack file");
enum object_type kind;
if (use_packed_git(p))
die("cannot map packed file");
offset = unpack_object_header(p, entry->offset, &kind, &size);
pack = p->pack_base + offset;
size = (pack[1] << 24) + (pack[2] << 16) + (pack[3] << 8) + pack[4];
left = p->pack_size - offset - 5;
switch (*pack) {
case 'D':
return unpack_delta_entry(pack+5, size, left, type, sizep);
case 'C':
left = p->pack_size - offset;
switch (kind) {
case OBJ_DELTA:
return unpack_delta_entry(pack, size, left, type, sizep);
case OBJ_COMMIT:
strcpy(type, "commit");
break;
case 'T':
case OBJ_TREE:
strcpy(type, "tree");
break;
case 'B':
case OBJ_BLOB:
strcpy(type, "blob");
break;
case 'G':
case OBJ_TAG:
strcpy(type, "tag");
break;
default:
die("corrupted pack file");
}
*sizep = size;
return unpack_non_delta_entry(pack+5, size, left);
return unpack_non_delta_entry(pack, size, left);
}
static int find_pack_entry_1(const unsigned char *sha1,