pack-objects: Prefer shallower deltas if the size is equal

Change "try_delta" so that if it finds a delta that has the same size
but shallower depth than the existing delta, it will prefer the
shallower one.  This makes certain delta trees vastly less deep.

Signed-off-by: Brian Downing <bdowning@lavos.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
This commit is contained in:
Brian Downing 2007-07-08 23:45:21 -05:00 committed by Junio C Hamano
parent 1ed84157a2
commit 848d732c10

View file

@ -1337,7 +1337,7 @@ static int try_delta(struct unpacked *trg, struct unpacked *src,
if (max_size == 0)
return 0;
if (trg_entry->delta && trg_entry->delta_size <= max_size)
max_size = trg_entry->delta_size-1;
max_size = trg_entry->delta_size;
src_size = src_entry->size;
sizediff = src_size < trg_size ? trg_size - src_size : 0;
if (sizediff >= max_size)
@ -1371,6 +1371,12 @@ static int try_delta(struct unpacked *trg, struct unpacked *src,
return 0;
if (trg_entry->delta_data) {
/* Prefer only shallower same-sized deltas. */
if (delta_size == trg_entry->delta_size &&
src_entry->depth + 1 >= trg_entry->depth) {
free(delta_buf);
return 0;
}
delta_cache_size -= trg_entry->delta_size;
free(trg_entry->delta_data);
}