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diff --git a/patch-ids.c b/patch-ids.c
index 3be5d3165e0009761a0ca69e15e4a9132c6cfaff..5717257051aceff129a4d0777c0a11bc156cae54 100644 (file)
--- a/patch-ids.c
+++ b/patch-ids.c
#include "cache.h"
#include "diff.h"
#include "commit.h"
+#include "sha1-lookup.h"
#include "patch-ids.h"
static int commit_patch_id(struct commit *commit, struct diff_options *options,
return diff_flush_patch_id(options, sha1);
}
-static uint32_t take2(const unsigned char *id)
+static const unsigned char *patch_id_access(size_t index, void *table)
{
- return ((id[0] << 8) | id[1]);
+ struct patch_id **id_table = table;
+ return id_table[index]->patch_id;
}
-/*
- * Conventional binary search loop looks like this:
- *
- * do {
- * int mi = (lo + hi) / 2;
- * int cmp = "entry pointed at by mi" minus "target";
- * if (!cmp)
- * return (mi is the wanted one)
- * if (cmp > 0)
- * hi = mi; "mi is larger than target"
- * else
- * lo = mi+1; "mi is smaller than target"
- * } while (lo < hi);
- *
- * The invariants are:
- *
- * - When entering the loop, lo points at a slot that is never
- * above the target (it could be at the target), hi points at a
- * slot that is guaranteed to be above the target (it can never
- * be at the target).
- *
- * - We find a point 'mi' between lo and hi (mi could be the same
- * as lo, but never can be the same as hi), and check if it hits
- * the target. There are three cases:
- *
- * - if it is a hit, we are happy.
- *
- * - if it is strictly higher than the target, we update hi with
- * it.
- *
- * - if it is strictly lower than the target, we update lo to be
- * one slot after it, because we allow lo to be at the target.
- *
- * When choosing 'mi', we do not have to take the "middle" but
- * anywhere in between lo and hi, as long as lo <= mi < hi is
- * satisfied. When we somehow know that the distance between the
- * target and lo is much shorter than the target and hi, we could
- * pick mi that is much closer to lo than the midway.
- */
static int patch_pos(struct patch_id **table, int nr, const unsigned char *id)
{
- int hi = nr;
- int lo = 0;
- int mi = 0;
-
- if (!nr)
- return -1;
-
- if (nr != 1) {
- unsigned lov, hiv, miv, ofs;
-
- for (ofs = 0; ofs < 18; ofs += 2) {
- lov = take2(table[0]->patch_id + ofs);
- hiv = take2(table[nr-1]->patch_id + ofs);
- miv = take2(id + ofs);
- if (miv < lov)
- return -1;
- if (hiv < miv)
- return -1 - nr;
- if (lov != hiv) {
- /*
- * At this point miv could be equal
- * to hiv (but id could still be higher);
- * the invariant of (mi < hi) should be
- * kept.
- */
- mi = (nr-1) * (miv - lov) / (hiv - lov);
- if (lo <= mi && mi < hi)
- break;
- die("oops");
- }
- }
- if (18 <= ofs)
- die("cannot happen -- lo and hi are identical");
- }
-
- do {
- int cmp;
- cmp = hashcmp(table[mi]->patch_id, id);
- if (!cmp)
- return mi;
- if (cmp > 0)
- hi = mi;
- else
- lo = mi + 1;
- mi = (hi + lo) / 2;
- } while (lo < hi);
- return -lo-1;
+ return sha1_pos(id, table, nr, patch_id_access);
}
#define BUCKET_SIZE 190 /* 190 * 21 = 3990, with slop close enough to 4K */