xz/src/liblzma/lzma/lzma_encoder_init.c

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///////////////////////////////////////////////////////////////////////////////
//
/// \file lzma_encoder_init.c
/// \brief Creating, resetting and destroying the LZMA encoder
//
// Copyright (C) 1999-2006 Igor Pavlov
// Copyright (C) 2007 Lasse Collin
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
//
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
// Lesser General Public License for more details.
//
///////////////////////////////////////////////////////////////////////////////
#include "lzma_encoder_private.h"
/// \brief Initializes the length encoder
static void
length_encoder_reset(lzma_length_encoder *lencoder,
const uint32_t num_pos_states, const uint32_t table_size)
{
// NLength::CPriceTableEncoder::SetTableSize()
lencoder->table_size = table_size;
// NLength::CEncoder::Init()
bit_reset(lencoder->choice);
bit_reset(lencoder->choice2);
for (size_t pos_state = 0; pos_state < num_pos_states; ++pos_state) {
bittree_reset(lencoder->low[pos_state], LEN_LOW_BITS);
bittree_reset(lencoder->mid[pos_state], LEN_MID_BITS);
}
bittree_reset(lencoder->high, LEN_HIGH_BITS);
// NLength::CPriceTableEncoder::UpdateTables()
for (size_t pos_state = 0; pos_state < num_pos_states; ++pos_state)
lzma_length_encoder_update_table(lencoder, pos_state);
return;
}
static void
lzma_lzma_encoder_end(lzma_coder *coder, lzma_allocator *allocator)
{
lzma_lz_encoder_end(&coder->lz, allocator);
lzma_literal_end(&coder->literal_coder, allocator);
lzma_free(coder, allocator);
return;
}
extern lzma_ret
lzma_lzma_encoder_init(lzma_next_coder *next, lzma_allocator *allocator,
const lzma_filter_info *filters)
{
if (next->coder == NULL) {
next->coder = lzma_alloc(sizeof(lzma_coder), allocator);
if (next->coder == NULL)
return LZMA_MEM_ERROR;
next->coder->next = LZMA_NEXT_CODER_INIT;
next->coder->lz = LZMA_LZ_ENCODER_INIT;
next->coder->literal_coder = NULL;
}
// Validate options that aren't validated elsewhere.
const lzma_options_lzma *options = filters[0].options;
if (options->pos_bits > LZMA_POS_BITS_MAX
|| options->fast_bytes < LZMA_FAST_BYTES_MIN
|| options->fast_bytes > LZMA_FAST_BYTES_MAX) {
lzma_lzma_encoder_end(next->coder, allocator);
return LZMA_HEADER_ERROR;
}
// Set compression mode.
switch (options->mode) {
case LZMA_MODE_FAST:
next->coder->best_compression = false;
break;
case LZMA_MODE_BEST:
next->coder->best_compression = true;
break;
default:
lzma_lzma_encoder_end(next->coder, allocator);
return LZMA_HEADER_ERROR;
}
// Initialize literal coder.
{
const lzma_ret ret = lzma_literal_init(
&next->coder->literal_coder, allocator,
options->literal_context_bits,
options->literal_pos_bits);
if (ret != LZMA_OK) {
lzma_lzma_encoder_end(next->coder, allocator);
return ret;
}
}
// Initialize LZ encoder.
{
const lzma_ret ret = lzma_lz_encoder_reset(
&next->coder->lz, allocator, &lzma_lzma_encode,
filters[0].uncompressed_size,
options->dictionary_size, OPTS,
options->fast_bytes, MATCH_MAX_LEN + 1 + OPTS,
options->match_finder,
options->match_finder_cycles,
options->preset_dictionary,
options->preset_dictionary_size);
if (ret != LZMA_OK) {
lzma_lzma_encoder_end(next->coder, allocator);
return ret;
}
}
// Set dist_table_size.
{
// Round the dictionary size up to next 2^n.
uint32_t log_size;
for (log_size = 0; (UINT32_C(1) << log_size)
< options->dictionary_size; ++log_size) ;
next->coder->dist_table_size = log_size * 2;
}
// Misc FIXME desc
next->coder->align_price_count = UINT32_MAX;
next->coder->match_price_count = UINT32_MAX;
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next->coder->dictionary_size = options->dictionary_size;
next->coder->pos_mask = (1U << options->pos_bits) - 1;
next->coder->fast_bytes = options->fast_bytes;
// Range coder
rc_reset(next->coder->rc);
// State
next->coder->state = 0;
next->coder->previous_byte = 0;
for (size_t i = 0; i < REP_DISTANCES; ++i)
next->coder->rep_distances[i] = 0;
// Bit encoders
for (size_t i = 0; i < STATES; ++i) {
for (size_t j = 0; j <= next->coder->pos_mask; ++j) {
bit_reset(next->coder->is_match[i][j]);
bit_reset(next->coder->is_rep0_long[i][j]);
}
bit_reset(next->coder->is_rep[i]);
bit_reset(next->coder->is_rep0[i]);
bit_reset(next->coder->is_rep1[i]);
bit_reset(next->coder->is_rep2[i]);
}
for (size_t i = 0; i < FULL_DISTANCES - END_POS_MODEL_INDEX; ++i)
bit_reset(next->coder->pos_encoders[i]);
// Bit tree encoders
for (size_t i = 0; i < LEN_TO_POS_STATES; ++i)
bittree_reset(next->coder->pos_slot_encoder[i], POS_SLOT_BITS);
bittree_reset(next->coder->pos_align_encoder, ALIGN_BITS);
// Length encoders
length_encoder_reset(&next->coder->match_len_encoder,
1U << options->pos_bits,
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options->fast_bytes + 1 - MATCH_MIN_LEN);
length_encoder_reset(&next->coder->rep_len_encoder,
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1U << options->pos_bits,
next->coder->fast_bytes + 1 - MATCH_MIN_LEN);
// Misc
next->coder->longest_match_was_found = false;
next->coder->optimum_end_index = 0;
next->coder->optimum_current_index = 0;
next->coder->additional_offset = 0;
next->coder->now_pos = 0;
next->coder->is_initialized = false;
// Initialize the next decoder in the chain, if any.
{
const lzma_ret ret = lzma_next_filter_init(&next->coder->next,
allocator, filters + 1);
if (ret != LZMA_OK) {
lzma_lzma_encoder_end(next->coder, allocator);
return ret;
}
}
// Initialization successful. Set the function pointers.
next->code = &lzma_lz_encode;
next->end = &lzma_lzma_encoder_end;
return LZMA_OK;
}
extern bool
lzma_lzma_encode_properties(const lzma_options_lzma *options, uint8_t *byte)
{
if (options->literal_context_bits > LZMA_LITERAL_CONTEXT_BITS_MAX
|| options->literal_pos_bits
> LZMA_LITERAL_POS_BITS_MAX
|| options->pos_bits > LZMA_POS_BITS_MAX)
return true;
*byte = (options->pos_bits * 5 + options->literal_pos_bits) * 9
+ options->literal_context_bits;
assert(*byte <= (4 * 5 + 4) * 9 + 8);
return false;
}