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authorJunio C Hamano <gitster@pobox.com>2018-02-27 10:34:03 -0800
committerJunio C Hamano <gitster@pobox.com>2018-02-27 10:34:03 -0800
commitf2fcbeb3bf2dfc198e9727d7c5fec15fa7a00a5c (patch)
tree0798cdd80a1645f4d638b89cb9f4da0e775a2556 /sha1-lookup.c
parentMerge branch 'rd/typofix' (diff)
parentpackfile: refactor hash search with fanout table (diff)
downloadgit-f2fcbeb3bf2dfc198e9727d7c5fec15fa7a00a5c.tar.gz
git-f2fcbeb3bf2dfc198e9727d7c5fec15fa7a00a5c.zip
Merge branch 'jt/binsearch-with-fanout'
Refactor the code to binary search starting from a fan-out table (which is how the packfile is indexed with object names) into a reusable helper. * jt/binsearch-with-fanout: packfile: refactor hash search with fanout table packfile: remove GIT_DEBUG_LOOKUP log statements
Diffstat (limited to 'sha1-lookup.c')
-rw-r--r--sha1-lookup.c28
1 files changed, 28 insertions, 0 deletions
diff --git a/sha1-lookup.c b/sha1-lookup.c
index 4cf3ebd921..8d0b1db3e2 100644
--- a/sha1-lookup.c
+++ b/sha1-lookup.c
@@ -99,3 +99,31 @@ int sha1_pos(const unsigned char *sha1, void *table, size_t nr,
} while (lo < hi);
return -lo-1;
}
+
+int bsearch_hash(const unsigned char *sha1, const uint32_t *fanout_nbo,
+ const unsigned char *table, size_t stride, uint32_t *result)
+{
+ uint32_t hi, lo;
+
+ hi = ntohl(fanout_nbo[*sha1]);
+ lo = ((*sha1 == 0x0) ? 0 : ntohl(fanout_nbo[*sha1 - 1]));
+
+ while (lo < hi) {
+ unsigned mi = lo + (hi - lo) / 2;
+ int cmp = hashcmp(table + mi * stride, sha1);
+
+ if (!cmp) {
+ if (result)
+ *result = mi;
+ return 1;
+ }
+ if (cmp > 0)
+ hi = mi;
+ else
+ lo = mi + 1;
+ }
+
+ if (result)
+ *result = lo;
+ return 0;
+}