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pack-redundant.c: learn about index v2

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Initially the conversion was made using nth_packed_object_sha1() which
made this file completely index version agnostic. Unfortunately the
overhead was quite significant so I went back to raw index walking but
with selectable base and step values which brought back similar
performances as the original.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>
This commit is contained in:
Nicolas Pitre 2007-04-09 01:06:37 -04:00 committed by Junio C Hamano
parent 32637cdf4a
commit 8c681e07c9
1 changed files with 27 additions and 20 deletions
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47
pack-redundant.c
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@ -247,16 +247,19 @@ static struct pack_list * pack_list_difference(const struct pack_list *A,
static void cmp_two_packs(struct pack_list *p1, struct pack_list *p2)
{
int p1_off, p2_off;
unsigned long p1_off = 0, p2_off = 0, p1_step, p2_step;
const unsigned char *p1_base, *p2_base;
struct llist_item *p1_hint = NULL, *p2_hint = NULL;
p1_off = p2_off = 256 * 4 + 4;
p1_base = p1->pack->index_data;
p2_base = p2->pack->index_data;
p1_base += 256 * 4 + ((p1->pack->index_version < 2) ? 4 : 8);
p2_base += 256 * 4 + ((p2->pack->index_version < 2) ? 4 : 8);
p1_step = (p1->pack->index_version < 2) ? 24 : 20;
p2_step = (p2->pack->index_version < 2) ? 24 : 20;
while (p1_off <= p1->pack->index_size - 3 * 20 &&
p2_off <= p2->pack->index_size - 3 * 20)
while (p1_off < p1->pack->num_objects * p1_step &&
p2_off < p2->pack->num_objects * p2_step)
{
int cmp = hashcmp(p1_base + p1_off, p2_base + p2_off);
/* cmp ~ p1 - p2 */
@ -265,14 +268,14 @@ static void cmp_two_packs(struct pack_list *p1, struct pack_list *p2)
p1_base + p1_off, p1_hint);
p2_hint = llist_sorted_remove(p2->unique_objects,
p1_base + p1_off, p2_hint);
p1_off+=24;
p2_off+=24;
p1_off += p1_step;
p2_off += p2_step;
continue;
}
if (cmp < 0) { /* p1 has the object, p2 doesn't */
p1_off+=24;
p1_off += p1_step;
} else { /* p2 has the object, p1 doesn't */
p2_off+=24;
p2_off += p2_step;
}
}
}
@ -352,28 +355,31 @@ static int is_superset(struct pack_list *pl, struct llist *list)
static size_t sizeof_union(struct packed_git *p1, struct packed_git *p2)
{
size_t ret = 0;
int p1_off, p2_off;
unsigned long p1_off = 0, p2_off = 0, p1_step, p2_step;
const unsigned char *p1_base, *p2_base;
p1_off = p2_off = 256 * 4 + 4;
p1_base = p1->index_data;
p2_base = p2->index_data;
p1_base += 256 * 4 + ((p1->index_version < 2) ? 4 : 8);
p2_base += 256 * 4 + ((p2->index_version < 2) ? 4 : 8);
p1_step = (p1->index_version < 2) ? 24 : 20;
p2_step = (p2->index_version < 2) ? 24 : 20;
while (p1_off <= p1->index_size - 3 * 20 &&
p2_off <= p2->index_size - 3 * 20)
while (p1_off < p1->num_objects * p1_step &&
p2_off < p2->num_objects * p2_step)
{
int cmp = hashcmp(p1_base + p1_off, p2_base + p2_off);
/* cmp ~ p1 - p2 */
if (cmp == 0) {
ret++;
p1_off+=24;
p2_off+=24;
p1_off += p1_step;
p2_off += p2_step;
continue;
}
if (cmp < 0) { /* p1 has the object, p2 doesn't */
p1_off+=24;
p1_off += p1_step;
} else { /* p2 has the object, p1 doesn't */
p2_off+=24;
p2_off += p2_step;
}
}
return ret;
@ -535,7 +541,7 @@ static void scan_alt_odb_packs(void)
static struct pack_list * add_pack(struct packed_git *p)
{
struct pack_list l;
size_t off;
unsigned long off = 0, step;
const unsigned char *base;
if (!p->pack_local && !(alt_odb || verbose))
@ -544,11 +550,12 @@ static struct pack_list * add_pack(struct packed_git *p)
l.pack = p;
llist_init(&l.all_objects);
off = 256 * 4 + 4;
base = p->index_data;
while (off <= p->index_size - 3 * 20) {
base += 256 * 4 + ((p->index_version < 2) ? 4 : 8);
step = (p->index_version < 2) ? 24 : 20;
while (off < p->num_objects * step) {
llist_insert_back(l.all_objects, base + off);
off += 24;
off += step;
}
/* this list will be pruned in cmp_two_packs later */
l.unique_objects = llist_copy(l.all_objects);