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DEFINITIONS
This source file includes following definitions.
- get_literal_price
- get_len_price
- get_short_rep_price
- get_pure_rep_price
- get_rep_price
- get_pos_len_price
- fill_distances_prices
- fill_align_prices
- make_literal
- make_short_rep
- backward
- helper1
- helper2
- lzma_lzma_optimum_normal
///////////////////////////////////////////////////////////////////////////////
//
/// \file lzma_encoder_optimum_normal.c
//
// Author: Igor Pavlov
//
// This file has been put into the public domain.
// You can do whatever you want with this file.
//
///////////////////////////////////////////////////////////////////////////////
#include "lzma_encoder_private.h"
#include "fastpos.h"
////////////
// Prices //
////////////
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 uint32_t
get_len_price(const lzma_length_encoder *const lencoder,
const uint32_t len, const uint32_t pos_state)
{
// NOTE: Unlike the other price tables, length prices are updated
// in lzma_encoder.c
return lencoder->prices[pos_state][len - MATCH_LEN_MIN];
}
static inline uint32_t
get_short_rep_price(const lzma_coder *const coder,
const lzma_lzma_state state, const uint32_t pos_state)
{
return rc_bit_0_price(coder->is_rep0[state])
+ rc_bit_0_price(coder->is_rep0_long[state][pos_state]);
}
static inline uint32_t
get_pure_rep_price(const lzma_coder *const coder, const uint32_t rep_index,
const lzma_lzma_state state, uint32_t pos_state)
{
uint32_t price;
if (rep_index == 0) {
price = rc_bit_0_price(coder->is_rep0[state]);
price += rc_bit_1_price(coder->is_rep0_long[state][pos_state]);
} else {
price = rc_bit_1_price(coder->is_rep0[state]);
if (rep_index == 1) {
price += rc_bit_0_price(coder->is_rep1[state]);
} else {
price += rc_bit_1_price(coder->is_rep1[state]);
price += rc_bit_price(coder->is_rep2[state],
rep_index - 2);
}
}
return price;
}
static inline uint32_t
get_rep_price(const lzma_coder *const coder, const uint32_t rep_index,
const uint32_t len, const lzma_lzma_state state,
const uint32_t pos_state)
{
return get_len_price(&coder->rep_len_encoder, len, pos_state)
+ get_pure_rep_price(coder, rep_index, state, pos_state);
}
static inline uint32_t
get_pos_len_price(const lzma_coder *const coder, const uint32_t pos,
const uint32_t len, const uint32_t pos_state)
{
const uint32_t len_to_pos_state = get_len_to_pos_state(len);
uint32_t price;
if (pos < FULL_DISTANCES) {
price = coder->distances_prices[len_to_pos_state][pos];
} else {
const uint32_t pos_slot = get_pos_slot_2(pos);
price = coder->pos_slot_prices[len_to_pos_state][pos_slot]
+ coder->align_prices[pos & ALIGN_MASK];
}
price += get_len_price(&coder->match_len_encoder, len, pos_state);
return price;
}
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 void
fill_align_prices(lzma_coder *coder)
{
for (uint32_t i = 0; i < ALIGN_TABLE_SIZE; ++i)
coder->align_prices[i] = rc_bittree_reverse_price(
coder->pos_align, ALIGN_BITS, i);
coder->align_price_count = 0;
return;
}
/////////////
// Optimal //
/////////////
static inline void
make_literal(lzma_optimal *optimal)
{
optimal->back_prev = UINT32_MAX;
optimal->prev_1_is_literal = false;
}
static inline void
make_short_rep(lzma_optimal *optimal)
{
optimal->back_prev = 0;
optimal->prev_1_is_literal = false;
}
#define is_short_rep(optimal) \
((optimal).back_prev == 0)
static void
backward(lzma_coder *restrict coder, uint32_t *restrict len_res,
uint32_t *restrict back_res, uint32_t cur)
{
coder->opts_end_index = cur;
uint32_t pos_mem = coder->opts[cur].pos_prev;
uint32_t back_mem = coder->opts[cur].back_prev;
do {
if (coder->opts[cur].prev_1_is_literal) {
make_literal(&coder->opts[pos_mem]);
coder->opts[pos_mem].pos_prev = pos_mem - 1;
if (coder->opts[cur].prev_2) {
coder->opts[pos_mem - 1].prev_1_is_literal
= false;
coder->opts[pos_mem - 1].pos_prev
= coder->opts[cur].pos_prev_2;
coder->opts[pos_mem - 1].back_prev
= coder->opts[cur].back_prev_2;
}
}
const uint32_t pos_prev = pos_mem;
const uint32_t back_cur = back_mem;
back_mem = coder->opts[pos_prev].back_prev;
pos_mem = coder->opts[pos_prev].pos_prev;
coder->opts[pos_prev].back_prev = back_cur;
coder->opts[pos_prev].pos_prev = cur;
cur = pos_prev;
} while (cur != 0);
coder->opts_current_index = coder->opts[0].pos_prev;
*len_res = coder->opts[0].pos_prev;
*back_res = coder->opts[0].back_prev;
return;
}
//////////
// Main //
//////////
static inline uint32_t
helper1(lzma_coder *restrict coder, lzma_mf *restrict mf,
uint32_t *restrict back_res, uint32_t *restrict len_res,
uint32_t position)
{
const uint32_t nice_len = mf->nice_len;
uint32_t len_main;
uint32_t matches_count;
if (mf->read_ahead == 0) {
len_main = mf_find(mf, &matches_count, coder->matches);
} else {
assert(mf->read_ahead == 1);
len_main = coder->longest_match_length;
matches_count = coder->matches_count;
}
const uint32_t buf_avail = my_min(mf_avail(mf) + 1, MATCH_LEN_MAX);
if (buf_avail < 2) {
*back_res = UINT32_MAX;
*len_res = 1;
return UINT32_MAX;
}
const uint8_t *const buf = mf_ptr(mf) - 1;
uint32_t rep_lens[REP_DISTANCES];
uint32_t rep_max_index = 0;
for (uint32_t i = 0; i < REP_DISTANCES; ++i) {
const uint8_t *const buf_back = buf - coder->reps[i] - 1;
if (not_equal_16(buf, buf_back)) {
rep_lens[i] = 0;
continue;
}
uint32_t len_test;
for (len_test = 2; len_test < buf_avail
&& buf[len_test] == buf_back[len_test];
++len_test) ;
rep_lens[i] = len_test;
if (len_test > rep_lens[rep_max_index])
rep_max_index = i;
}
if (rep_lens[rep_max_index] >= nice_len) {
*back_res = rep_max_index;
*len_res = rep_lens[rep_max_index];
mf_skip(mf, *len_res - 1);
return UINT32_MAX;
}
if (len_main >= nice_len) {
*back_res = coder->matches[matches_count - 1].dist
+ REP_DISTANCES;
*len_res = len_main;
mf_skip(mf, len_main - 1);
return UINT32_MAX;
}
const uint8_t current_byte = *buf;
const uint8_t match_byte = *(buf - coder->reps[0] - 1);
if (len_main < 2 && current_byte != match_byte
&& rep_lens[rep_max_index] < 2) {
*back_res = UINT32_MAX;
*len_res = 1;
return UINT32_MAX;
}
coder->opts[0].state = coder->state;
const uint32_t pos_state = position & coder->pos_mask;
coder->opts[1].price = rc_bit_0_price(
coder->is_match[coder->state][pos_state])
+ get_literal_price(coder, position, buf[-1],
!is_literal_state(coder->state),
match_byte, current_byte);
make_literal(&coder->opts[1]);
const uint32_t match_price = rc_bit_1_price(
coder->is_match[coder->state][pos_state]);
const uint32_t rep_match_price = match_price
+ rc_bit_1_price(coder->is_rep[coder->state]);
if (match_byte == current_byte) {
const uint32_t short_rep_price = rep_match_price
+ get_short_rep_price(
coder, coder->state, pos_state);
if (short_rep_price < coder->opts[1].price) {
coder->opts[1].price = short_rep_price;
make_short_rep(&coder->opts[1]);
}
}
const uint32_t len_end = my_max(len_main, rep_lens[rep_max_index]);
if (len_end < 2) {
*back_res = coder->opts[1].back_prev;
*len_res = 1;
return UINT32_MAX;
}
coder->opts[1].pos_prev = 0;
for (uint32_t i = 0; i < REP_DISTANCES; ++i)
coder->opts[0].backs[i] = coder->reps[i];
uint32_t len = len_end;
do {
coder->opts[len].price = RC_INFINITY_PRICE;
} while (--len >= 2);
for (uint32_t i = 0; i < REP_DISTANCES; ++i) {
uint32_t rep_len = rep_lens[i];
if (rep_len < 2)
continue;
const uint32_t price = rep_match_price + get_pure_rep_price(
coder, i, coder->state, pos_state);
do {
const uint32_t cur_and_len_price = price
+ get_len_price(
&coder->rep_len_encoder,
rep_len, pos_state);
if (cur_and_len_price < coder->opts[rep_len].price) {
coder->opts[rep_len].price = cur_and_len_price;
coder->opts[rep_len].pos_prev = 0;
coder->opts[rep_len].back_prev = i;
coder->opts[rep_len].prev_1_is_literal = false;
}
} while (--rep_len >= 2);
}
const uint32_t normal_match_price = match_price
+ rc_bit_0_price(coder->is_rep[coder->state]);
len = rep_lens[0] >= 2 ? rep_lens[0] + 1 : 2;
if (len <= len_main) {
uint32_t i = 0;
while (len > coder->matches[i].len)
++i;
for(; ; ++len) {
const uint32_t dist = coder->matches[i].dist;
const uint32_t cur_and_len_price = normal_match_price
+ get_pos_len_price(coder,
dist, len, pos_state);
if (cur_and_len_price < coder->opts[len].price) {
coder->opts[len].price = cur_and_len_price;
coder->opts[len].pos_prev = 0;
coder->opts[len].back_prev
= dist + REP_DISTANCES;
coder->opts[len].prev_1_is_literal = false;
}
if (len == coder->matches[i].len)
if (++i == matches_count)
break;
}
}
return len_end;
}
static inline uint32_t
helper2(lzma_coder *coder, uint32_t *reps, const uint8_t *buf,
uint32_t len_end, uint32_t position, const uint32_t cur,
const uint32_t nice_len, const uint32_t buf_avail_full)
{
uint32_t matches_count = coder->matches_count;
uint32_t new_len = coder->longest_match_length;
uint32_t pos_prev = coder->opts[cur].pos_prev;
lzma_lzma_state state;
if (coder->opts[cur].prev_1_is_literal) {
--pos_prev;
if (coder->opts[cur].prev_2) {
state = coder->opts[coder->opts[cur].pos_prev_2].state;
if (coder->opts[cur].back_prev_2 < REP_DISTANCES)
update_long_rep(state);
else
update_match(state);
} else {
state = coder->opts[pos_prev].state;
}
update_literal(state);
} else {
state = coder->opts[pos_prev].state;
}
if (pos_prev == cur - 1) {
if (is_short_rep(coder->opts[cur]))
update_short_rep(state);
else
update_literal(state);
} else {
uint32_t pos;
if (coder->opts[cur].prev_1_is_literal
&& coder->opts[cur].prev_2) {
pos_prev = coder->opts[cur].pos_prev_2;
pos = coder->opts[cur].back_prev_2;
update_long_rep(state);
} else {
pos = coder->opts[cur].back_prev;
if (pos < REP_DISTANCES)
update_long_rep(state);
else
update_match(state);
}
if (pos < REP_DISTANCES) {
reps[0] = coder->opts[pos_prev].backs[pos];
uint32_t i;
for (i = 1; i <= pos; ++i)
reps[i] = coder->opts[pos_prev].backs[i - 1];
for (; i < REP_DISTANCES; ++i)
reps[i] = coder->opts[pos_prev].backs[i];
} else {
reps[0] = pos - REP_DISTANCES;
for (uint32_t i = 1; i < REP_DISTANCES; ++i)
reps[i] = coder->opts[pos_prev].backs[i - 1];
}
}
coder->opts[cur].state = state;
for (uint32_t i = 0; i < REP_DISTANCES; ++i)
coder->opts[cur].backs[i] = reps[i];
const uint32_t cur_price = coder->opts[cur].price;
const uint8_t current_byte = *buf;
const uint8_t match_byte = *(buf - reps[0] - 1);
const uint32_t pos_state = position & coder->pos_mask;
const uint32_t cur_and_1_price = cur_price
+ rc_bit_0_price(coder->is_match[state][pos_state])
+ get_literal_price(coder, position, buf[-1],
!is_literal_state(state), match_byte, current_byte);
bool next_is_literal = false;
if (cur_and_1_price < coder->opts[cur + 1].price) {
coder->opts[cur + 1].price = cur_and_1_price;
coder->opts[cur + 1].pos_prev = cur;
make_literal(&coder->opts[cur + 1]);
next_is_literal = true;
}
const uint32_t match_price = cur_price
+ rc_bit_1_price(coder->is_match[state][pos_state]);
const uint32_t rep_match_price = match_price
+ rc_bit_1_price(coder->is_rep[state]);
if (match_byte == current_byte
&& !(coder->opts[cur + 1].pos_prev < cur
&& coder->opts[cur + 1].back_prev == 0)) {
const uint32_t short_rep_price = rep_match_price
+ get_short_rep_price(coder, state, pos_state);
if (short_rep_price <= coder->opts[cur + 1].price) {
coder->opts[cur + 1].price = short_rep_price;
coder->opts[cur + 1].pos_prev = cur;
make_short_rep(&coder->opts[cur + 1]);
next_is_literal = true;
}
}
if (buf_avail_full < 2)
return len_end;
const uint32_t buf_avail = my_min(buf_avail_full, nice_len);
if (!next_is_literal && match_byte != current_byte) { // speed optimization
// try literal + rep0
const uint8_t *const buf_back = buf - reps[0] - 1;
const uint32_t limit = my_min(buf_avail_full, nice_len + 1);
uint32_t len_test = 1;
while (len_test < limit && buf[len_test] == buf_back[len_test])
++len_test;
--len_test;
if (len_test >= 2) {
lzma_lzma_state state_2 = state;
update_literal(state_2);
const uint32_t pos_state_next = (position + 1) & coder->pos_mask;
const uint32_t next_rep_match_price = cur_and_1_price
+ rc_bit_1_price(coder->is_match[state_2][pos_state_next])
+ rc_bit_1_price(coder->is_rep[state_2]);
//for (; len_test >= 2; --len_test) {
const uint32_t offset = cur + 1 + len_test;
while (len_end < offset)
coder->opts[++len_end].price = RC_INFINITY_PRICE;
const uint32_t cur_and_len_price = next_rep_match_price
+ get_rep_price(coder, 0, len_test,
state_2, pos_state_next);
if (cur_and_len_price < coder->opts[offset].price) {
coder->opts[offset].price = cur_and_len_price;
coder->opts[offset].pos_prev = cur + 1;
coder->opts[offset].back_prev = 0;
coder->opts[offset].prev_1_is_literal = true;
coder->opts[offset].prev_2 = false;
}
//}
}
}
uint32_t start_len = 2; // speed optimization
for (uint32_t rep_index = 0; rep_index < REP_DISTANCES; ++rep_index) {
const uint8_t *const buf_back = buf - reps[rep_index] - 1;
if (not_equal_16(buf, buf_back))
continue;
uint32_t len_test;
for (len_test = 2; len_test < buf_avail
&& buf[len_test] == buf_back[len_test];
++len_test) ;
while (len_end < cur + len_test)
coder->opts[++len_end].price = RC_INFINITY_PRICE;
const uint32_t len_test_temp = len_test;
const uint32_t price = rep_match_price + get_pure_rep_price(
coder, rep_index, state, pos_state);
do {
const uint32_t cur_and_len_price = price
+ get_len_price(&coder->rep_len_encoder,
len_test, pos_state);
if (cur_and_len_price < coder->opts[cur + len_test].price) {
coder->opts[cur + len_test].price = cur_and_len_price;
coder->opts[cur + len_test].pos_prev = cur;
coder->opts[cur + len_test].back_prev = rep_index;
coder->opts[cur + len_test].prev_1_is_literal = false;
}
} while (--len_test >= 2);
len_test = len_test_temp;
if (rep_index == 0)
start_len = len_test + 1;
uint32_t len_test_2 = len_test + 1;
const uint32_t limit = my_min(buf_avail_full,
len_test_2 + nice_len);
for (; len_test_2 < limit
&& buf[len_test_2] == buf_back[len_test_2];
++len_test_2) ;
len_test_2 -= len_test + 1;
if (len_test_2 >= 2) {
lzma_lzma_state state_2 = state;
update_long_rep(state_2);
uint32_t pos_state_next = (position + len_test) & coder->pos_mask;
const uint32_t cur_and_len_literal_price = price
+ get_len_price(&coder->rep_len_encoder,
len_test, pos_state)
+ rc_bit_0_price(coder->is_match[state_2][pos_state_next])
+ get_literal_price(coder, position + len_test,
buf[len_test - 1], true,
buf_back[len_test], buf[len_test]);
update_literal(state_2);
pos_state_next = (position + len_test + 1) & coder->pos_mask;
const uint32_t next_rep_match_price = cur_and_len_literal_price
+ rc_bit_1_price(coder->is_match[state_2][pos_state_next])
+ rc_bit_1_price(coder->is_rep[state_2]);
//for(; len_test_2 >= 2; len_test_2--) {
const uint32_t offset = cur + len_test + 1 + len_test_2;
while (len_end < offset)
coder->opts[++len_end].price = RC_INFINITY_PRICE;
const uint32_t cur_and_len_price = next_rep_match_price
+ get_rep_price(coder, 0, len_test_2,
state_2, pos_state_next);
if (cur_and_len_price < coder->opts[offset].price) {
coder->opts[offset].price = cur_and_len_price;
coder->opts[offset].pos_prev = cur + len_test + 1;
coder->opts[offset].back_prev = 0;
coder->opts[offset].prev_1_is_literal = true;
coder->opts[offset].prev_2 = true;
coder->opts[offset].pos_prev_2 = cur;
coder->opts[offset].back_prev_2 = rep_index;
}
//}
}
}
//for (uint32_t len_test = 2; len_test <= new_len; ++len_test)
if (new_len > buf_avail) {
new_len = buf_avail;
matches_count = 0;
while (new_len > coder->matches[matches_count].len)
++matches_count;
coder->matches[matches_count++].len = new_len;
}
if (new_len >= start_len) {
const uint32_t normal_match_price = match_price
+ rc_bit_0_price(coder->is_rep[state]);
while (len_end < cur + new_len)
coder->opts[++len_end].price = RC_INFINITY_PRICE;
uint32_t i = 0;
while (start_len > coder->matches[i].len)
++i;
for (uint32_t len_test = start_len; ; ++len_test) {
const uint32_t cur_back = coder->matches[i].dist;
uint32_t cur_and_len_price = normal_match_price
+ get_pos_len_price(coder,
cur_back, len_test, pos_state);
if (cur_and_len_price < coder->opts[cur + len_test].price) {
coder->opts[cur + len_test].price = cur_and_len_price;
coder->opts[cur + len_test].pos_prev = cur;
coder->opts[cur + len_test].back_prev
= cur_back + REP_DISTANCES;
coder->opts[cur + len_test].prev_1_is_literal = false;
}
if (len_test == coder->matches[i].len) {
// Try Match + Literal + Rep0
const uint8_t *const buf_back = buf - cur_back - 1;
uint32_t len_test_2 = len_test + 1;
const uint32_t limit = my_min(buf_avail_full,
len_test_2 + nice_len);
for (; len_test_2 < limit &&
buf[len_test_2] == buf_back[len_test_2];
++len_test_2) ;
len_test_2 -= len_test + 1;
if (len_test_2 >= 2) {
lzma_lzma_state state_2 = state;
update_match(state_2);
uint32_t pos_state_next
= (position + len_test) & coder->pos_mask;
const uint32_t cur_and_len_literal_price = cur_and_len_price
+ rc_bit_0_price(
coder->is_match[state_2][pos_state_next])
+ get_literal_price(coder,
position + len_test,
buf[len_test - 1],
true,
buf_back[len_test],
buf[len_test]);
update_literal(state_2);
pos_state_next = (pos_state_next + 1) & coder->pos_mask;
const uint32_t next_rep_match_price
= cur_and_len_literal_price
+ rc_bit_1_price(
coder->is_match[state_2][pos_state_next])
+ rc_bit_1_price(coder->is_rep[state_2]);
// for(; len_test_2 >= 2; --len_test_2) {
const uint32_t offset = cur + len_test + 1 + len_test_2;
while (len_end < offset)
coder->opts[++len_end].price = RC_INFINITY_PRICE;
cur_and_len_price = next_rep_match_price
+ get_rep_price(coder, 0, len_test_2,
state_2, pos_state_next);
if (cur_and_len_price < coder->opts[offset].price) {
coder->opts[offset].price = cur_and_len_price;
coder->opts[offset].pos_prev = cur + len_test + 1;
coder->opts[offset].back_prev = 0;
coder->opts[offset].prev_1_is_literal = true;
coder->opts[offset].prev_2 = true;
coder->opts[offset].pos_prev_2 = cur;
coder->opts[offset].back_prev_2
= cur_back + REP_DISTANCES;
}
//}
}
if (++i == matches_count)
break;
}
}
}
return len_end;
}
extern void
lzma_lzma_optimum_normal(lzma_coder *restrict coder, lzma_mf *restrict mf,
uint32_t *restrict back_res, uint32_t *restrict len_res,
uint32_t position)
{
// If we have symbols pending, return the next pending symbol.
if (coder->opts_end_index != coder->opts_current_index) {
assert(mf->read_ahead > 0);
*len_res = coder->opts[coder->opts_current_index].pos_prev
- coder->opts_current_index;
*back_res = coder->opts[coder->opts_current_index].back_prev;
coder->opts_current_index = coder->opts[
coder->opts_current_index].pos_prev;
return;
}
// Update the price tables. In LZMA SDK <= 4.60 (and possibly later)
// this was done in both initialization function and in the main loop.
// In liblzma they were moved into this single place.
if (mf->read_ahead == 0) {
if (coder->match_price_count >= (1 << 7))
fill_distances_prices(coder);
if (coder->align_price_count >= ALIGN_TABLE_SIZE)
fill_align_prices(coder);
}
// TODO: This needs quite a bit of cleaning still. But splitting
// the original function into two pieces makes it at least a little
// more readable, since those two parts don't share many variables.
uint32_t len_end = helper1(coder, mf, back_res, len_res, position);
if (len_end == UINT32_MAX)
return;
uint32_t reps[REP_DISTANCES];
memcpy(reps, coder->reps, sizeof(reps));
uint32_t cur;
for (cur = 1; cur < len_end; ++cur) {
assert(cur < OPTS);
coder->longest_match_length = mf_find(
mf, &coder->matches_count, coder->matches);
if (coder->longest_match_length >= mf->nice_len)
break;
len_end = helper2(coder, reps, mf_ptr(mf) - 1, len_end,
position + cur, cur, mf->nice_len,
my_min(mf_avail(mf) + 1, OPTS - 1 - cur));
}
backward(coder, len_res, back_res, cur);
return;
}