in android/com/facebook/buck/android/agent/native/miniz.c [2357:2492]
static mz_bool tdefl_compress_fast(tdefl_compressor *d)
{
// Faster, minimally featured LZRW1-style match+parse loop with better register utilization. Intended for applications where raw throughput is valued more highly than ratio.
mz_uint lookahead_pos = d->m_lookahead_pos, lookahead_size = d->m_lookahead_size, dict_size = d->m_dict_size, total_lz_bytes = d->m_total_lz_bytes, num_flags_left = d->m_num_flags_left;
mz_uint8 *pLZ_code_buf = d->m_pLZ_code_buf, *pLZ_flags = d->m_pLZ_flags;
mz_uint cur_pos = lookahead_pos & TDEFL_LZ_DICT_SIZE_MASK;
while ((d->m_src_buf_left) || ((d->m_flush) && (lookahead_size)))
{
const mz_uint TDEFL_COMP_FAST_LOOKAHEAD_SIZE = 4096;
mz_uint dst_pos = (lookahead_pos + lookahead_size) & TDEFL_LZ_DICT_SIZE_MASK;
mz_uint num_bytes_to_process = (mz_uint)MZ_MIN(d->m_src_buf_left, TDEFL_COMP_FAST_LOOKAHEAD_SIZE - lookahead_size);
d->m_src_buf_left -= num_bytes_to_process;
lookahead_size += num_bytes_to_process;
while (num_bytes_to_process)
{
mz_uint32 n = MZ_MIN(TDEFL_LZ_DICT_SIZE - dst_pos, num_bytes_to_process);
memcpy(d->m_dict + dst_pos, d->m_pSrc, n);
if (dst_pos < (TDEFL_MAX_MATCH_LEN - 1))
memcpy(d->m_dict + TDEFL_LZ_DICT_SIZE + dst_pos, d->m_pSrc, MZ_MIN(n, (TDEFL_MAX_MATCH_LEN - 1) - dst_pos));
d->m_pSrc += n;
dst_pos = (dst_pos + n) & TDEFL_LZ_DICT_SIZE_MASK;
num_bytes_to_process -= n;
}
dict_size = MZ_MIN(TDEFL_LZ_DICT_SIZE - lookahead_size, dict_size);
if ((!d->m_flush) && (lookahead_size < TDEFL_COMP_FAST_LOOKAHEAD_SIZE)) break;
while (lookahead_size >= 4)
{
mz_uint cur_match_dist, cur_match_len = 1;
mz_uint8 *pCur_dict = d->m_dict + cur_pos;
mz_uint first_trigram = (*(const mz_uint32 *)pCur_dict) & 0xFFFFFF;
mz_uint hash = (first_trigram ^ (first_trigram >> (24 - (TDEFL_LZ_HASH_BITS - 8)))) & TDEFL_LEVEL1_HASH_SIZE_MASK;
mz_uint probe_pos = d->m_hash[hash];
d->m_hash[hash] = (mz_uint16)lookahead_pos;
if (((cur_match_dist = (mz_uint16)(lookahead_pos - probe_pos)) <= dict_size) && ((*(const mz_uint32 *)(d->m_dict + (probe_pos &= TDEFL_LZ_DICT_SIZE_MASK)) & 0xFFFFFF) == first_trigram))
{
const mz_uint16 *p = (const mz_uint16 *)pCur_dict;
const mz_uint16 *q = (const mz_uint16 *)(d->m_dict + probe_pos);
mz_uint32 probe_len = 32;
do { } while ( (TDEFL_READ_UNALIGNED_WORD(++p) == TDEFL_READ_UNALIGNED_WORD(++q)) && (TDEFL_READ_UNALIGNED_WORD(++p) == TDEFL_READ_UNALIGNED_WORD(++q)) &&
(TDEFL_READ_UNALIGNED_WORD(++p) == TDEFL_READ_UNALIGNED_WORD(++q)) && (TDEFL_READ_UNALIGNED_WORD(++p) == TDEFL_READ_UNALIGNED_WORD(++q)) && (--probe_len > 0) );
cur_match_len = ((mz_uint)(p - (const mz_uint16 *)pCur_dict) * 2) + (mz_uint)(*(const mz_uint8 *)p == *(const mz_uint8 *)q);
if (!probe_len)
cur_match_len = cur_match_dist ? TDEFL_MAX_MATCH_LEN : 0;
if ((cur_match_len < TDEFL_MIN_MATCH_LEN) || ((cur_match_len == TDEFL_MIN_MATCH_LEN) && (cur_match_dist >= 8U*1024U)))
{
cur_match_len = 1;
*pLZ_code_buf++ = (mz_uint8)first_trigram;
*pLZ_flags = (mz_uint8)(*pLZ_flags >> 1);
d->m_huff_count[0][(mz_uint8)first_trigram]++;
}
else
{
mz_uint32 s0, s1;
cur_match_len = MZ_MIN(cur_match_len, lookahead_size);
MZ_ASSERT((cur_match_len >= TDEFL_MIN_MATCH_LEN) && (cur_match_dist >= 1) && (cur_match_dist <= TDEFL_LZ_DICT_SIZE));
cur_match_dist--;
pLZ_code_buf[0] = (mz_uint8)(cur_match_len - TDEFL_MIN_MATCH_LEN);
*(mz_uint16 *)(&pLZ_code_buf[1]) = (mz_uint16)cur_match_dist;
pLZ_code_buf += 3;
*pLZ_flags = (mz_uint8)((*pLZ_flags >> 1) | 0x80);
s0 = s_tdefl_small_dist_sym[cur_match_dist & 511];
s1 = s_tdefl_large_dist_sym[cur_match_dist >> 8];
d->m_huff_count[1][(cur_match_dist < 512) ? s0 : s1]++;
d->m_huff_count[0][s_tdefl_len_sym[cur_match_len - TDEFL_MIN_MATCH_LEN]]++;
}
}
else
{
*pLZ_code_buf++ = (mz_uint8)first_trigram;
*pLZ_flags = (mz_uint8)(*pLZ_flags >> 1);
d->m_huff_count[0][(mz_uint8)first_trigram]++;
}
if (--num_flags_left == 0) { num_flags_left = 8; pLZ_flags = pLZ_code_buf++; }
total_lz_bytes += cur_match_len;
lookahead_pos += cur_match_len;
dict_size = MZ_MIN(dict_size + cur_match_len, TDEFL_LZ_DICT_SIZE);
cur_pos = (cur_pos + cur_match_len) & TDEFL_LZ_DICT_SIZE_MASK;
MZ_ASSERT(lookahead_size >= cur_match_len);
lookahead_size -= cur_match_len;
if (pLZ_code_buf > &d->m_lz_code_buf[TDEFL_LZ_CODE_BUF_SIZE - 8])
{
int n;
d->m_lookahead_pos = lookahead_pos; d->m_lookahead_size = lookahead_size; d->m_dict_size = dict_size;
d->m_total_lz_bytes = total_lz_bytes; d->m_pLZ_code_buf = pLZ_code_buf; d->m_pLZ_flags = pLZ_flags; d->m_num_flags_left = num_flags_left;
if ((n = tdefl_flush_block(d, 0)) != 0)
return (n < 0) ? MZ_FALSE : MZ_TRUE;
total_lz_bytes = d->m_total_lz_bytes; pLZ_code_buf = d->m_pLZ_code_buf; pLZ_flags = d->m_pLZ_flags; num_flags_left = d->m_num_flags_left;
}
}
while (lookahead_size)
{
mz_uint8 lit = d->m_dict[cur_pos];
total_lz_bytes++;
*pLZ_code_buf++ = lit;
*pLZ_flags = (mz_uint8)(*pLZ_flags >> 1);
if (--num_flags_left == 0) { num_flags_left = 8; pLZ_flags = pLZ_code_buf++; }
d->m_huff_count[0][lit]++;
lookahead_pos++;
dict_size = MZ_MIN(dict_size + 1, TDEFL_LZ_DICT_SIZE);
cur_pos = (cur_pos + 1) & TDEFL_LZ_DICT_SIZE_MASK;
lookahead_size--;
if (pLZ_code_buf > &d->m_lz_code_buf[TDEFL_LZ_CODE_BUF_SIZE - 8])
{
int n;
d->m_lookahead_pos = lookahead_pos; d->m_lookahead_size = lookahead_size; d->m_dict_size = dict_size;
d->m_total_lz_bytes = total_lz_bytes; d->m_pLZ_code_buf = pLZ_code_buf; d->m_pLZ_flags = pLZ_flags; d->m_num_flags_left = num_flags_left;
if ((n = tdefl_flush_block(d, 0)) != 0)
return (n < 0) ? MZ_FALSE : MZ_TRUE;
total_lz_bytes = d->m_total_lz_bytes; pLZ_code_buf = d->m_pLZ_code_buf; pLZ_flags = d->m_pLZ_flags; num_flags_left = d->m_num_flags_left;
}
}
}
d->m_lookahead_pos = lookahead_pos; d->m_lookahead_size = lookahead_size; d->m_dict_size = dict_size;
d->m_total_lz_bytes = total_lz_bytes; d->m_pLZ_code_buf = pLZ_code_buf; d->m_pLZ_flags = pLZ_flags; d->m_num_flags_left = num_flags_left;
return MZ_TRUE;
}