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deflate_compress: add deflate_write_bits() helper function

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This commit is contained in:
Eric Biggers 2022-01-20 23:36:02 -08:00
parent 194f6a447f
commit 80364d70c6
1 changed files with 20 additions and 12 deletions
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32
lib/deflate_compress.c
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@ -684,7 +684,7 @@ deflate_init_output(struct deflate_output_bitstream *os,
*/ */
static forceinline void static forceinline void
deflate_add_bits(struct deflate_output_bitstream *os, deflate_add_bits(struct deflate_output_bitstream *os,
const bitbuf_t bits, const unsigned num_bits) bitbuf_t bits, unsigned num_bits)
{ {
os->bitbuf |= bits << os->bitcount; os->bitbuf |= bits << os->bitcount;
os->bitcount += num_bits; os->bitcount += num_bits;
@ -712,6 +712,18 @@ deflate_flush_bits(struct deflate_output_bitstream *os)
} }
} }
/*
* Add bits, then flush right away. Only use this where it is difficult to
* batch up calls to deflate_add_bits().
*/
static forceinline void
deflate_write_bits(struct deflate_output_bitstream *os,
bitbuf_t bits, unsigned num_bits)
{
deflate_add_bits(os, bits, num_bits);
deflate_flush_bits(os);
}
/* Align the bitstream on a byte boundary. */ /* Align the bitstream on a byte boundary. */
static forceinline void static forceinline void
deflate_align_bitstream(struct deflate_output_bitstream *os) deflate_align_bitstream(struct deflate_output_bitstream *os)
@ -1610,9 +1622,8 @@ deflate_write_huffman_header(struct libdeflate_compressor *c,
/* Output the lengths of the codewords in the precode. */ /* Output the lengths of the codewords in the precode. */
for (i = 0; i < c->num_explicit_lens; i++) { for (i = 0; i < c->num_explicit_lens; i++) {
deflate_add_bits(os, c->precode_lens[ deflate_write_bits(os, c->precode_lens[
deflate_precode_lens_permutation[i]], 3); deflate_precode_lens_permutation[i]], 3);
deflate_flush_bits(os);
} }
/* Output the encoded lengths of the codewords in the larger code. */ /* Output the encoded lengths of the codewords in the larger code. */
@ -1696,9 +1707,8 @@ deflate_write_literal_run(struct deflate_output_bitstream *os,
do { do {
unsigned lit = *in_next++; unsigned lit = *in_next++;
deflate_add_bits(os, codes->codewords.litlen[lit], deflate_write_bits(os, codes->codewords.litlen[lit],
codes->lens.litlen[lit]); codes->lens.litlen[lit]);
deflate_flush_bits(os);
} while (--litrunlen); } while (--litrunlen);
#endif #endif
} }
@ -1792,9 +1802,8 @@ deflate_write_item_list(struct deflate_output_bitstream *os,
if (length == 1) { if (length == 1) {
/* Literal */ /* Literal */
deflate_add_bits(os, codes->codewords.litlen[offset], deflate_write_bits(os, codes->codewords.litlen[offset],
codes->lens.litlen[offset]); codes->lens.litlen[offset]);
deflate_flush_bits(os);
} else { } else {
/* Match */ /* Match */
deflate_write_match(os, length, deflate_write_match(os, length,
@ -1813,9 +1822,8 @@ static void
deflate_write_end_of_block(struct deflate_output_bitstream *os, deflate_write_end_of_block(struct deflate_output_bitstream *os,
const struct deflate_codes *codes) const struct deflate_codes *codes)
{ {
deflate_add_bits(os, codes->codewords.litlen[DEFLATE_END_OF_BLOCK], deflate_write_bits(os, codes->codewords.litlen[DEFLATE_END_OF_BLOCK],
codes->lens.litlen[DEFLATE_END_OF_BLOCK]); codes->lens.litlen[DEFLATE_END_OF_BLOCK]);
deflate_flush_bits(os);
} }
static void static void