static uint32_t
get_literal_price(const lzma_coder *const coder, const uint32_t pos,
const uint32_t prev_byte, const bool match_mode,
uint32_t match_byte, uint32_t symbol)
{
const probability *const subcoder = literal_subcoder(coder->literal,
coder->literal_context_bits, coder->literal_pos_mask,
pos, prev_byte);
uint32_t price = 0;
if (!match_mode) {
price = rc_bittree_price(subcoder, 8, symbol);
} else {
uint32_t offset = 0x100;
symbol += UINT32_C(1) << 8;
do {
match_byte <<= 1;
const uint32_t match_bit = match_byte & offset;
const uint32_t subcoder_index
= offset + match_bit + (symbol >> 8);
const uint32_t bit = (symbol >> 7) & 1;
price += rc_bit_price(subcoder[subcoder_index], bit);
symbol <<= 1;
offset &= ~(match_byte ^ symbol);
} while (symbol < (UINT32_C(1) << 16));
}
return price;
}
static inline void
literal(lzma_lzma1_encoder *coder, lzma_mf *mf, uint32_t position)
{
// Locate the literal byte to be encoded and the subcoder.
const uint8_t cur_byte = mf->buffer[
mf->read_pos - mf->read_ahead];
probability *subcoder = literal_subcoder(coder->literal,
coder->literal_context_bits, coder->literal_pos_mask,
position, mf->buffer[mf->read_pos - mf->read_ahead - 1]);
if (is_literal_state(coder->state)) {
// Previous LZMA-symbol was a literal. Encode a normal
// literal without a match byte.
rc_bittree(&coder->rc, subcoder, 8, cur_byte);
} else {
// Previous LZMA-symbol was a match. Use the last byte of
// the match as a "match byte". That is, compare the bits
// of the current literal and the match byte.
const uint8_t match_byte = mf->buffer[
mf->read_pos - coder->reps[0] - 1
- mf->read_ahead];
literal_matched(&coder->rc, subcoder, match_byte, cur_byte);
}
update_literal(coder->state);
}
