Commit 3c7ceba4 authored by Linus Torvalds's avatar Linus Torvalds Committed by Junio C Hamano

diffcore-delta: 64-byte-or-EOL ultrafast replacement.

Signed-off-by: default avatarJunio C Hamano <[email protected]>
parent 90bd932c
......@@ -99,7 +99,7 @@ static struct spanhash_top *spanhash_rehash(struct spanhash_top *orig)
}
static struct spanhash_top *add_spanhash(struct spanhash_top *top,
unsigned long hashval)
unsigned long hashval, int cnt)
{
int bucket, lim;
struct spanhash *h;
......@@ -110,14 +110,14 @@ static struct spanhash_top *add_spanhash(struct spanhash_top *top,
h = &(top->data[bucket++]);
if (!h->cnt) {
h->hashval = hashval;
h->cnt = 1;
h->cnt = cnt;
top->free--;
if (top->free < 0)
return spanhash_rehash(top);
return top;
}
if (h->hashval == hashval) {
h->cnt++;
h->cnt += cnt;
return top;
}
if (lim <= bucket)
......@@ -127,7 +127,7 @@ static struct spanhash_top *add_spanhash(struct spanhash_top *top,
static struct spanhash_top *hash_chars(unsigned char *buf, unsigned long sz)
{
int i;
int i, n;
unsigned long accum1, accum2, hashval;
struct spanhash_top *hash;
......@@ -137,19 +137,20 @@ static struct spanhash_top *hash_chars(unsigned char *buf, unsigned long sz)
hash->free = INITIAL_FREE(i);
memset(hash->data, 0, sizeof(struct spanhash) * (1<<i));
/* an 8-byte shift register made of accum1 and accum2. New
* bytes come at LSB of accum2, and shifted up to accum1
*/
for (i = accum1 = accum2 = 0; i < 7; i++, sz--) {
accum1 = (accum1 << 8) | (accum2 >> 24);
accum2 = (accum2 << 8) | *buf++;
}
n = 0;
accum1 = accum2 = 0;
while (sz) {
accum1 = (accum1 << 8) | (accum2 >> 24);
accum2 = (accum2 << 8) | *buf++;
hashval = (accum1 + accum2 * 0x61) % HASHBASE;
hash = add_spanhash(hash, hashval);
unsigned long c = *buf++;
sz--;
accum1 = (accum1 << 7) | (accum2 >> 25);
accum2 = (accum2 << 7) | (accum1 >> 25);
accum1 += c;
if (++n < 64 && c != '\n')
continue;
hashval = (accum1 + accum2 * 0x61) % HASHBASE;
hash = add_spanhash(hash, hashval, n);
n = 0;
accum1 = accum2 = 0;
}
return hash;
}
......@@ -166,9 +167,6 @@ int diffcore_count_changes(void *src, unsigned long src_size,
struct spanhash_top *src_count, *dst_count;
unsigned long sc, la;
if (src_size < 8 || dst_size < 8)
return -1;
src_count = dst_count = NULL;
if (src_count_p)
src_count = *src_count_p;
......
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