static void
fill_distances_prices(lzma_coder *coder)
{
for (uint32_t len_to_pos_state = 0;
len_to_pos_state < LEN_TO_POS_STATES;
++len_to_pos_state) {
uint32_t *const pos_slot_prices
= coder->pos_slot_prices[len_to_pos_state];
// Price to encode the pos_slot.
for (uint32_t pos_slot = 0;
pos_slot < coder->dist_table_size; ++pos_slot)
pos_slot_prices[pos_slot] = rc_bittree_price(
coder->pos_slot[len_to_pos_state],
POS_SLOT_BITS, pos_slot);
// For matches with distance >= FULL_DISTANCES, add the price
// of the direct bits part of the match distance. (Align bits
// are handled by fill_align_prices()).
for (uint32_t pos_slot = END_POS_MODEL_INDEX;
pos_slot < coder->dist_table_size; ++pos_slot)
pos_slot_prices[pos_slot] += rc_direct_price(
((pos_slot >> 1) - 1) - ALIGN_BITS);
// Distances in the range [0, 3] are fully encoded with
// pos_slot, so they are used for coder->distances_prices
// as is.
for (uint32_t i = 0; i < START_POS_MODEL_INDEX; ++i)
coder->distances_prices[len_to_pos_state][i]
= pos_slot_prices[i];
}
// Distances in the range [4, 127] depend on pos_slot and pos_special.
// We do this in a loop separate from the above loop to avoid
// redundant calls to get_pos_slot().
for (uint32_t i = START_POS_MODEL_INDEX; i < FULL_DISTANCES; ++i) {
const uint32_t pos_slot = get_pos_slot(i);
const uint32_t footer_bits = ((pos_slot >> 1) - 1);
const uint32_t base = (2 | (pos_slot & 1)) << footer_bits;
const uint32_t price = rc_bittree_reverse_price(
coder->pos_special + base - pos_slot - 1,
footer_bits, i - base);
for (uint32_t len_to_pos_state = 0;
len_to_pos_state < LEN_TO_POS_STATES;
++len_to_pos_state)
coder->distances_prices[len_to_pos_state][i]
= price + coder->pos_slot_prices[
len_to_pos_state][pos_slot];
}
coder->match_price_count = 0;
return;
}
static inline void
match(lzma_coder *coder, const uint32_t pos_state,
const uint32_t distance, const uint32_t len)
{
update_match(coder->state);
length(&coder->rc, &coder->match_len_encoder, pos_state, len,
coder->fast_mode);
const uint32_t pos_slot = get_pos_slot(distance);
const uint32_t len_to_pos_state = get_len_to_pos_state(len);
rc_bittree(&coder->rc, coder->pos_slot[len_to_pos_state],
POS_SLOT_BITS, pos_slot);
if (pos_slot >= START_POS_MODEL_INDEX) {
const uint32_t footer_bits = (pos_slot >> 1) - 1;
const uint32_t base = (2 | (pos_slot & 1)) << footer_bits;
const uint32_t pos_reduced = distance - base;
if (pos_slot < END_POS_MODEL_INDEX) {
// Careful here: base - pos_slot - 1 can be -1, but
// rc_bittree_reverse starts at probs[1], not probs[0].
rc_bittree_reverse(&coder->rc,
coder->pos_special + base - pos_slot - 1,
footer_bits, pos_reduced);
} else {
rc_direct(&coder->rc, pos_reduced >> ALIGN_BITS,
footer_bits - ALIGN_BITS);
rc_bittree_reverse(
&coder->rc, coder->pos_align,
ALIGN_BITS, pos_reduced & ALIGN_MASK);
++coder->align_price_count;
}
}
coder->reps[3] = coder->reps[2];
coder->reps[2] = coder->reps[1];
coder->reps[1] = coder->reps[0];
coder->reps[0] = distance;
++coder->match_price_count;
}
