Function reuse_partial_packfile_from_bitmap_1

pack-bitmap.c:2358–2448

}

static void reuse_partial_packfile_from_bitmap_1(struct bitmap_index *bitmap_git,
						 struct bitmapped_pack *pack,
						 struct bitmap *reuse)
{
	struct bitmap *result = bitmap_git->result;
	struct pack_window *w_curs = NULL;
	size_t pos = pack->bitmap_pos / BITS_IN_EWORD;

	if (!pack->bitmap_pos) {
		/*
		 * If we're processing the first (in the case of a MIDX, the
		 * preferred pack) or the only (in the case of single-pack
		 * bitmaps) pack, then we can reuse whole words at a time.
		 *
		 * This is because we know that any deltas in this range *must*
		 * have their bases chosen from the same pack, since:
		 *
		 * - In the single pack case, there is no other pack to choose
		 *   them from.
		 *
		 * - In the MIDX case, the first pack is the preferred pack, so
		 *   all ties are broken in favor of that pack (i.e. the one
		 *   we're currently processing). So any duplicate bases will be
		 *   resolved in favor of the pack we're processing.
		 */
		while (pos < result->word_alloc &&
		       pos < pack->bitmap_nr / BITS_IN_EWORD &&
		       result->words[pos] == (eword_t)~0)
			pos++;
		memset(reuse->words, 0xFF, pos * sizeof(eword_t));
	}

	for (; pos < result->word_alloc; pos++) {
		eword_t word = result->words[pos];
		size_t offset;

		for (offset = 0; offset < BITS_IN_EWORD; offset++) {
			size_t bit_pos;
			uint32_t pack_pos;
			off_t ofs;

			if (word >> offset == 0)
				break;

			offset += ewah_bit_ctz64(word >> offset);

			bit_pos = pos * BITS_IN_EWORD + offset;
			if (bit_pos < pack->bitmap_pos)
				continue;
			if (bit_pos >= pack->bitmap_pos + pack->bitmap_nr)
				goto done;

			if (bitmap_is_midx(bitmap_git)) {
				uint32_t midx_pos;

				midx_pos = pack_pos_to_midx(bitmap_git->midx, bit_pos);
				ofs = nth_midxed_offset(bitmap_git->midx, midx_pos);