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Speed up sort comparator function.

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This commit is contained in:
Moinak Ghosh 2012-08-17 13:18:50 +05:30
parent 2dadf411fa
commit 023dcae19a
1 changed files with 11 additions and 8 deletions
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19
rabin/rabin_polynomial.c
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@ -264,18 +264,21 @@ cmpblks(const void *a, const void *b)
if (a1->cksum_n_offset < b1->cksum_n_offset) {
return (-1);
} else if (a1->cksum_n_offset == b1->cksum_n_offset) {
int l1 = a1->length;
int l2 = b1->length;
/*
* If fingerprints match then compare lengths. Length match makes
* for strong exact detection/ordering during sort while stopping
* short of expensive memcmp().
* short of expensive memcmp() during sorting.
*
* Even though rabin_blockentry_t->length is unsigned we use signed
* int here to avoid branches. In practice a rabin block size at
* this point varies from 2K to 128K. The length is unsigned in
* order to support non-duplicate block merging and large blocks
* after this point.
*/
if (a1->length < b1->length) {
return (-1);
} else if (a1->length == b1->length) {
return (0);
} else {
return (1);
}
return (l1 - l2);
} else {
return (1);
}