deflate_compress: refactor writing literals into separate function

Avoid too many levels of indentation.
This commit is contained in:
Eric Biggers 2022-01-04 21:15:30 -08:00
parent f6e7593cfc
commit 08692b8696

View File

@ -1592,23 +1592,12 @@ deflate_write_huffman_header(struct libdeflate_compressor *c,
} }
} }
static void static forceinline void
deflate_write_sequences(struct deflate_output_bitstream * restrict os, deflate_write_literal_run(struct deflate_output_bitstream *os,
const struct deflate_codes * restrict codes, const u8 *in_next, u32 litrunlen,
const struct deflate_sequence sequences[restrict], const struct deflate_codes *codes)
const u8 * restrict in_next)
{ {
const struct deflate_sequence *seq = sequences; #if 1
for (;;) {
u32 litrunlen = seq->litrunlen_and_length & 0x7FFFFF;
unsigned length = seq->litrunlen_and_length >> 23;
unsigned length_slot;
unsigned litlen_symbol;
unsigned offset_symbol;
if (litrunlen) {
#if 1
while (litrunlen >= 4) { while (litrunlen >= 4) {
unsigned lit0 = in_next[0]; unsigned lit0 = in_next[0];
unsigned lit1 = in_next[1]; unsigned lit1 = in_next[1];
@ -1649,7 +1638,8 @@ deflate_write_sequences(struct deflate_output_bitstream * restrict os,
deflate_flush_bits(os); deflate_flush_bits(os);
in_next++; in_next++;
if (litrunlen-- != 0) { if (litrunlen-- != 0) {
deflate_add_bits(os, codes->codewords.litlen[*in_next], deflate_add_bits(os,
codes->codewords.litlen[*in_next],
codes->lens.litlen[*in_next]); codes->lens.litlen[*in_next]);
if (!CAN_BUFFER(3 * MAX_LITLEN_CODEWORD_LEN)) if (!CAN_BUFFER(3 * MAX_LITLEN_CODEWORD_LEN))
deflate_flush_bits(os); deflate_flush_bits(os);
@ -1659,14 +1649,36 @@ deflate_write_sequences(struct deflate_output_bitstream * restrict os,
if (CAN_BUFFER(3 * MAX_LITLEN_CODEWORD_LEN)) if (CAN_BUFFER(3 * MAX_LITLEN_CODEWORD_LEN))
deflate_flush_bits(os); deflate_flush_bits(os);
} }
#else #else
do { do {
unsigned lit = *in_next++; unsigned lit = *in_next++;
deflate_add_bits(os, codes->codewords.litlen[lit], deflate_add_bits(os, codes->codewords.litlen[lit],
codes->lens.litlen[lit]); codes->lens.litlen[lit]);
deflate_flush_bits(os); deflate_flush_bits(os);
} while (--litrunlen); } while (--litrunlen);
#endif #endif
}
static void
deflate_write_sequences(struct deflate_output_bitstream * restrict os,
const struct deflate_codes * restrict codes,
const struct deflate_sequence sequences[restrict],
const u8 * restrict in_next)
{
const struct deflate_sequence *seq = sequences;
for (;;) {
u32 litrunlen = seq->litrunlen_and_length & 0x7FFFFF;
unsigned length = seq->litrunlen_and_length >> 23;
unsigned length_slot;
unsigned litlen_symbol;
unsigned offset_symbol;
if (litrunlen) {
deflate_write_literal_run(os, in_next, litrunlen,
codes);
in_next += litrunlen;
} }
if (length == 0) if (length == 0)