From d1a46a9eab2ce136240fe2e8db34b36338052e97 Mon Sep 17 00:00:00 2001 From: Nicolas Pitre Date: Mon, 9 Apr 2007 01:06:34 -0400 Subject: [PATCH] index-pack: learn about pack index version 2 Like previous patch but for index-pack. [ There is quite some code duplication between pack-objects and index-pack for generating a pack index (and fast-import as well I suppose). This should be reworked into a common function eventually. But not now. ] Signed-off-by: Nicolas Pitre Signed-off-by: Junio C Hamano --- index-pack.c | 66 +++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 57 insertions(+), 9 deletions(-) diff --git a/index-pack.c b/index-pack.c index d33f72336..a833f640f 100644 --- a/index-pack.c +++ b/index-pack.c @@ -686,9 +686,10 @@ static const char *write_index_file(const char *index_name, unsigned char *sha1) { struct sha1file *f; struct object_entry **sorted_by_sha, **list, **last; - unsigned int array[256]; + uint32_t array[256]; int i, fd; SHA_CTX ctx; + uint32_t index_version; if (nr_objects) { sorted_by_sha = @@ -699,7 +700,6 @@ static const char *write_index_file(const char *index_name, unsigned char *sha1) sorted_by_sha[i] = &objects[i]; qsort(sorted_by_sha, nr_objects, sizeof(sorted_by_sha[0]), sha1_compare); - } else sorted_by_sha = list = last = NULL; @@ -718,6 +718,17 @@ static const char *write_index_file(const char *index_name, unsigned char *sha1) die("unable to create %s: %s", index_name, strerror(errno)); f = sha1fd(fd, index_name); + /* if last object's offset is >= 2^31 we should use index V2 */ + index_version = (objects[nr_objects-1].offset >> 31) ? 2 : 1; + + /* index versions 2 and above need a header */ + if (index_version >= 2) { + struct pack_idx_header hdr; + hdr.idx_signature = htonl(PACK_IDX_SIGNATURE); + hdr.idx_version = htonl(index_version); + sha1write(f, &hdr, sizeof(hdr)); + } + /* * Write the first-level table (the list is sorted, * but we use a 256-entry lookup to be able to avoid @@ -734,24 +745,61 @@ static const char *write_index_file(const char *index_name, unsigned char *sha1) array[i] = htonl(next - sorted_by_sha); list = next; } - sha1write(f, array, 256 * sizeof(int)); + sha1write(f, array, 256 * 4); - /* recompute the SHA1 hash of sorted object names. - * currently pack-objects does not do this, but that - * can be fixed. - */ + /* compute the SHA1 hash of sorted object names. */ SHA1_Init(&ctx); + /* * Write the actual SHA1 entries.. */ list = sorted_by_sha; for (i = 0; i < nr_objects; i++) { struct object_entry *obj = *list++; - unsigned int offset = htonl(obj->offset); - sha1write(f, &offset, 4); + if (index_version < 2) { + uint32_t offset = htonl(obj->offset); + sha1write(f, &offset, 4); + } sha1write(f, obj->sha1, 20); SHA1_Update(&ctx, obj->sha1, 20); } + + if (index_version >= 2) { + unsigned int nr_large_offset = 0; + + /* write the crc32 table */ + list = sorted_by_sha; + for (i = 0; i < nr_objects; i++) { + struct object_entry *obj = *list++; + uint32_t crc32_val = htonl(obj->crc32); + sha1write(f, &crc32_val, 4); + } + + /* write the 32-bit offset table */ + list = sorted_by_sha; + for (i = 0; i < nr_objects; i++) { + struct object_entry *obj = *list++; + uint32_t offset = (obj->offset <= 0x7fffffff) ? + obj->offset : (0x80000000 | nr_large_offset++); + offset = htonl(offset); + sha1write(f, &offset, 4); + } + + /* write the large offset table */ + list = sorted_by_sha; + while (nr_large_offset) { + struct object_entry *obj = *list++; + uint64_t offset = obj->offset; + if (offset > 0x7fffffff) { + uint32_t split[2]; + split[0] = htonl(offset >> 32); + split[1] = htonl(offset & 0xffffffff); + sha1write(f, split, 8); + nr_large_offset--; + } + } + } + sha1write(f, sha1, 20); sha1close(f, NULL, 1); free(sorted_by_sha); -- 2.26.2