@matheusbsbs / matheus-bagliano / commits / e1bfe30c4d

pack-revindex: factor out `midx_key_to_pack_pos()` helper

The `midx_to_pack_pos()` function implements a binary search over objects in the MIDX between lexical and pseudo-pack order. It does this by taking in an index into the lexical order (i.e. the same argument you'd use for `nth_midxed_object_id()` and similar) and spits out a position in the pseudo-pack order. This works for all callers, since they currently all are translating from lexical order to pseudo-pack order. But future callers may want to translate a known (offset, pack_id) tuple into an index into the psuedo-pack order, without knowing where that (offset, pack_id) tuple appears in lexical order. Prepare for implementing a function that translates between a (offset, pack_id) tuple into an index into the psuedo-pack order by extracting a helper function which does just that, and then reimplementing midx_to_pack_pos() in terms of it. Signed-off-by: Taylor Blau <me@ttaylorr.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>

Taylor Blau committed Dec 14, 2023 at 17:24 UTC e1bfe30c4dd29a1a30569d04432d73675e497e86

1 file changed +24 -15

pack-revindex.c

+24 -15

@@ -520,19 +520,12 @@ static int midx_pack_order_cmp(const void *va, const void *vb)

520 return 0;

521 }

522

523 -int midx_to_pack_pos(struct multi_pack_index *m, uint32_t at, uint32_t *pos)

523 +static int midx_key_to_pack_pos(struct multi_pack_index *m,

524 + struct midx_pack_key *key,

525 + uint32_t *pos)

526 {

525 - struct midx_pack_key key;

527 uint32_t *found;

528

528 - if (!m->revindex_data)

529 - BUG("midx_to_pack_pos: reverse index not yet loaded");

530 - if (m->num_objects <= at)

531 - BUG("midx_to_pack_pos: out-of-bounds object at %"PRIu32, at);

532 -

533 - key.pack = nth_midxed_pack_int_id(m, at);

534 - key.offset = nth_midxed_offset(m, at);

535 - key.midx = m;

529 /*

530 * The preferred pack sorts first, so determine its identifier by

531 * looking at the first object in pseudo-pack order.

@@ -542,16 +535,32 @@ int midx_to_pack_pos(struct multi_pack_index *m, uint32_t at, uint32_t *pos)

535 * implicitly is preferred (and includes all its objects, since ties are

536 * broken first by pack identifier).

537 */

545 - if (midx_preferred_pack(key.midx, &key.preferred_pack) < 0)

538 + if (midx_preferred_pack(key->midx, &key->preferred_pack) < 0)

539 return error(_("could not determine preferred pack"));

540

548 -

549 - found = bsearch(&key, m->revindex_data, m->num_objects,

550 - sizeof(*m->revindex_data), midx_pack_order_cmp);

541 + found = bsearch(key, m->revindex_data, m->num_objects,

542 + sizeof(*m->revindex_data),

543 + midx_pack_order_cmp);

544

545 if (!found)

553 - return error("bad offset for revindex");

546 + return -1;

547

548 *pos = found - m->revindex_data;

549 return 0;

550 }

551 +

552 +int midx_to_pack_pos(struct multi_pack_index *m, uint32_t at, uint32_t *pos)

553 +{

554 + struct midx_pack_key key;

555 +

556 + if (!m->revindex_data)

557 + BUG("midx_to_pack_pos: reverse index not yet loaded");

558 + if (m->num_objects <= at)

559 + BUG("midx_to_pack_pos: out-of-bounds object at %"PRIu32, at);

560 +

561 + key.pack = nth_midxed_pack_int_id(m, at);

562 + key.offset = nth_midxed_offset(m, at);

563 + key.midx = m;

564 +

565 + return midx_key_to_pack_pos(m, &key, pos);

566 +}