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diffcore-delta: 64-byte-or-EOL ultrafast replacement (hash fix).

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The rotating 64-bit number was not really rotating, and worse
yet ulong was longer than 64-bit on 64-bit architectures X-<.

Signed-off-by: Junio C Hamano <junkio@cox.net>
This commit is contained in:
Linus Torvalds
2006-03-15 00:37:57 -08:00
committed by Junio C Hamano
parent 3c7ceba4f1
commit e31c9f241a
1 changed files with 10 additions and 9 deletions
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19
diffcore-delta.c
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@ -40,8 +40,8 @@
#define HASHBASE 107927 #define HASHBASE 107927
struct spanhash { struct spanhash {
unsigned long hashval; unsigned int hashval;
unsigned long cnt; unsigned int cnt;
}; };
struct spanhash_top { struct spanhash_top {
int alloc_log2; int alloc_log2;
@ -50,7 +50,7 @@ struct spanhash_top {
}; };
static struct spanhash *spanhash_find(struct spanhash_top *top, static struct spanhash *spanhash_find(struct spanhash_top *top,
unsigned long hashval) unsigned int hashval)
{ {
int sz = 1 << top->alloc_log2; int sz = 1 << top->alloc_log2;
int bucket = hashval & (sz - 1); int bucket = hashval & (sz - 1);
@ -99,7 +99,7 @@ static struct spanhash_top *spanhash_rehash(struct spanhash_top *orig)
} }
static struct spanhash_top *add_spanhash(struct spanhash_top *top, static struct spanhash_top *add_spanhash(struct spanhash_top *top,
unsigned long hashval, int cnt) unsigned int hashval, int cnt)
{ {
int bucket, lim; int bucket, lim;
struct spanhash *h; struct spanhash *h;
@ -125,10 +125,10 @@ static struct spanhash_top *add_spanhash(struct spanhash_top *top,
} }
} }
static struct spanhash_top *hash_chars(unsigned char *buf, unsigned long sz) static struct spanhash_top *hash_chars(unsigned char *buf, unsigned int sz)
{ {
int i, n; int i, n;
unsigned long accum1, accum2, hashval; unsigned int accum1, accum2, hashval;
struct spanhash_top *hash; struct spanhash_top *hash;
i = INITIAL_HASH_SIZE; i = INITIAL_HASH_SIZE;
@ -140,10 +140,11 @@ static struct spanhash_top *hash_chars(unsigned char *buf, unsigned long sz)
n = 0; n = 0;
accum1 = accum2 = 0; accum1 = accum2 = 0;
while (sz) { while (sz) {
unsigned long c = *buf++; unsigned int c = *buf++;
unsigned int old_1 = accum1;
sz--; sz--;
accum1 = (accum1 << 7) | (accum2 >> 25); accum1 = (accum1 << 7) ^ (accum2 >> 25);
accum2 = (accum2 << 7) | (accum1 >> 25); accum2 = (accum2 << 7) ^ (old_1 >> 25);
accum1 += c; accum1 += c;
if (++n < 64 && c != '\n') if (++n < 64 && c != '\n')
continue; continue;