diff options
author | Derrick Stolee <dstolee@microsoft.com> | 2018-03-22 13:40:09 -0400 |
---|---|---|
committer | Junio C Hamano <gitster@pobox.com> | 2018-03-22 11:00:07 -0700 |
commit | 3d475f46a8225a9cc549ac5cb2c51d6ecd9e0f7c (patch) | |
tree | 09459e67cb30070c566ceebc78d6a2b26547dc66 /packfile.c | |
parent | 626fd982a3ead1b0aae26c242fbabaaaaf4b6062 (diff) | |
download | git-3d475f46a8225a9cc549ac5cb2c51d6ecd9e0f7c.tar.gz |
packfile: define and use bsearch_pack()
The method bsearch_hash() generalizes binary searches using a
fanout table. The only consumer is currently find_pack_entry_one().
It requires a bit of pointer arithmetic to align the fanout table
and the lookup table depending on the pack-index version.
Extract the pack-index pointer arithmetic to a new method,
bsearch_pack(), so this can be re-used in other code paths.
Signed-off-by: Derrick Stolee <dstolee@microsoft.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'packfile.c')
-rw-r--r-- | packfile.c | 42 |
1 files changed, 26 insertions, 16 deletions
diff --git a/packfile.c b/packfile.c index f26395ecab..69d3afda6c 100644 --- a/packfile.c +++ b/packfile.c @@ -1654,6 +1654,29 @@ out: return data; } +int bsearch_pack(const struct object_id *oid, const struct packed_git *p, uint32_t *result) +{ + const unsigned char *index_fanout = p->index_data; + const unsigned char *index_lookup; + int index_lookup_width; + + if (!index_fanout) + BUG("bsearch_pack called without a valid pack-index"); + + index_lookup = index_fanout + 4 * 256; + if (p->index_version == 1) { + index_lookup_width = 24; + index_lookup += 4; + } else { + index_lookup_width = 20; + index_fanout += 8; + index_lookup += 8; + } + + return bsearch_hash(oid->hash, (const uint32_t*)index_fanout, + index_lookup, index_lookup_width, result); +} + const unsigned char *nth_packed_object_sha1(struct packed_git *p, uint32_t n) { @@ -1720,30 +1743,17 @@ off_t nth_packed_object_offset(const struct packed_git *p, uint32_t n) off_t find_pack_entry_one(const unsigned char *sha1, struct packed_git *p) { - const uint32_t *level1_ofs = p->index_data; const unsigned char *index = p->index_data; - unsigned stride; + struct object_id oid; uint32_t result; if (!index) { if (open_pack_index(p)) return 0; - level1_ofs = p->index_data; - index = p->index_data; - } - if (p->index_version > 1) { - level1_ofs += 2; - index += 8; - } - index += 4 * 256; - if (p->index_version > 1) { - stride = 20; - } else { - stride = 24; - index += 4; } - if (bsearch_hash(sha1, level1_ofs, index, stride, &result)) + hashcpy(oid.hash, sha1); + if (bsearch_pack(&oid, p, &result)) return nth_packed_object_offset(p, result); return 0; } |