///////////////////////////////////////////////////////////////////////////////
//
/// \file range_encoder.h
/// \brief Range 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.
//
///////////////////////////////////////////////////////////////////////////////
#ifndef LZMA_RANGE_ENCODER_H
#define LZMA_RANGE_ENCODER_H
#include "range_common.h"
// Allow #including this file even if RC_TEMP_BUFFER_SIZE isn't defined.
#ifdef RC_BUFFER_SIZE
typedef struct {
uint64_t low;
uint32_t range;
uint32_t cache_size;
uint8_t cache;
uint8_t buffer[RC_BUFFER_SIZE];
size_t buffer_size;
} lzma_range_encoder;
#endif
/// Makes local copies of range encoder variables.
#define rc_to_local(rc) \
uint64_t rc_low = (rc).low; \
uint32_t rc_range = (rc).range; \
uint32_t rc_cache_size = (rc).cache_size; \
uint8_t rc_cache = (rc).cache; \
uint8_t *rc_buffer = (rc).buffer; \
size_t rc_buffer_size = (rc).buffer_size
/// Stores the local copes back to the range encoder structure.
#define rc_from_local(rc) \
do { \
(rc).low = rc_low; \
(rc).range = rc_range; \
(rc).cache_size = rc_cache_size; \
(rc).cache = rc_cache; \
(rc).buffer_size = rc_buffer_size; \
} while (0)
/// Resets the range encoder structure.
#define rc_reset(rc) \
do { \
(rc).low = 0; \
(rc).range = 0xFFFFFFFF; \
(rc).cache_size = 1; \
(rc).cache = 0; \
(rc).buffer_size = 0; \
} while (0)
//////////////////
// Bit encoding //
//////////////////
// These macros expect that the following variables are defined:
// - uint64_t rc_low;
// - uint32_t rc_range;
// - uint8_t rc_cache;
// - uint32_t rc_cache_size;
// - uint8_t *out;
// - size_t out_pos_local; // Local copy of *out_pos
// - size_t size_out;
// Combined from NRangeCoder::CEncoder::Encode()
// and NRangeCoder::CEncoder::UpdateModel().
#define bit_encode(prob, symbol) \
do { \
probability rc_prob = prob; \
const uint32_t rc_bound \
= (rc_range >> BIT_MODEL_TOTAL_BITS) * rc_prob; \
if ((symbol) == 0) { \
rc_range = rc_bound; \
rc_prob += (BIT_MODEL_TOTAL - rc_prob) >> MOVE_BITS; \
} else { \
rc_low += rc_bound; \
rc_range -= rc_bound; \
rc_prob -= rc_prob >> MOVE_BITS; \
} \
prob = rc_prob; \
rc_normalize(); \
} while (0)
// Optimized version of bit_encode(prob, 0)
#define bit_encode_0(prob) \
do { \
probability rc_prob = prob; \
rc_range = (rc_range >> BIT_MODEL_TOTAL_BITS) * rc_prob; \
rc_prob += (BIT_MODEL_TOTAL - rc_prob) >> MOVE_BITS; \
prob = rc_prob; \
rc_normalize(); \
} while (0)
// Optimized version of bit_encode(prob, 1)
#define bit_encode_1(prob) \
do { \
probability rc_prob = prob; \
const uint32_t rc_bound = (rc_range >> BIT_MODEL_TOTAL_BITS) \
* rc_prob; \
rc_low += rc_bound; \
rc_range -= rc_bound; \
rc_prob -= rc_prob >> MOVE_BITS; \
prob = rc_prob; \
rc_normalize(); \
} while (0)
///////////////////////
// Bit tree encoding //
///////////////////////
#define bittree_encode(probs, bit_levels, symbol) \
do { \
uint32_t model_index = 1; \
for (int32_t bit_index = bit_levels - 1; \
bit_index >= 0; --bit_index) { \
const uint32_t bit = ((symbol) >> bit_index) & 1; \
bit_encode((probs)[model_index], bit); \
model_index = (model_index << 1) | bit; \
} \
} while (0)
#define bittree_reverse_encode(probs, bit_levels, symbol) \
do { \
uint32_t model_index = 1; \
for (uint32_t bit_index = 0; bit_index < bit_levels; ++bit_index) { \
const uint32_t bit = ((symbol) >> bit_index) & 1; \
bit_encode((probs)[model_index], bit); \
model_index = (model_index << 1) | bit; \
} \
} while (0)
/////////////////
// Direct bits //
/////////////////
#define rc_encode_direct_bits(value, num_total_bits) \
do { \
for (int32_t rc_i = (num_total_bits) - 1; rc_i >= 0; --rc_i) { \
rc_range >>= 1; \
if ((((value) >> rc_i) & 1) == 1) \
rc_low += rc_range; \
rc_normalize(); \
} \
} while (0)
//////////////////
// Buffer "I/O" //
//////////////////
// Calls rc_shift_low() to write out a byte if needed.
#define rc_normalize() \
do { \
if (rc_range < TOP_VALUE) { \
rc_range <<= SHIFT_BITS; \
rc_shift_low(); \
} \
} while (0)
// Flushes all the pending output.
#define rc_flush() \
for (int32_t rc_i = 0; rc_i < 5; ++rc_i) \
rc_shift_low()
// Writes the compressed data to next_out.
// TODO: Notation change?
// (uint32_t)(0xFF000000) => ((uint32_t)(0xFF) << TOP_BITS)
// TODO: Another notation change?
// rc_low = (uint32_t)(rc_low) << SHIFT_BITS;
// =>
// rc_low &= TOP_VALUE - 1;
// rc_low <<= SHIFT_BITS;
#define rc_shift_low() \
do { \
if ((uint32_t)(rc_low) < (uint32_t)(0xFF000000) \
|| (uint32_t)(rc_low >> 32) != 0) { \
uint8_t rc_temp = rc_cache; \
do { \
rc_write_byte(rc_temp + (uint8_t)(rc_low >> 32)); \
rc_temp = 0xFF; \
} while(--rc_cache_size != 0); \
rc_cache = (uint8_t)((uint32_t)(rc_low) >> 24); \
} \
++rc_cache_size; \
rc_low = (uint32_t)(rc_low) << SHIFT_BITS; \
} while (0)
// Write one byte of compressed data to *next_out. Updates out_pos_local.
// If out_pos_local == out_size, the byte is appended to rc_buffer.
#define rc_write_byte(b) \
do { \
if (out_pos_local == out_size) { \
rc_buffer[rc_buffer_size++] = (uint8_t)(b); \
assert(rc_buffer_size < RC_BUFFER_SIZE); \
} else { \
assert(rc_buffer_size == 0); \
out[out_pos_local++] = (uint8_t)(b); \
} \
} while (0)
//////////////////
// Price macros //
//////////////////
// These macros expect that the following variables are defined:
// - uint32_t lzma_rc_prob_prices;
#define bit_get_price(prob, symbol) \
lzma_rc_prob_prices[((((prob) - (symbol)) ^ (-(symbol))) \
& (BIT_MODEL_TOTAL - 1)) >> MOVE_REDUCING_BITS]
#define bit_get_price_0(prob) \
lzma_rc_prob_prices[(prob) >> MOVE_REDUCING_BITS]
#define bit_get_price_1(prob) \
lzma_rc_prob_prices[(BIT_MODEL_TOTAL - (prob)) >> MOVE_REDUCING_BITS]
// Adds price to price_target. TODO Optimize/Cleanup?
#define bittree_get_price(price_target, probs, bit_levels, symbol) \
do { \
uint32_t bittree_symbol = (symbol) | (UINT32_C(1) << bit_levels); \
while (bittree_symbol != 1) { \
price_target += bit_get_price((probs)[bittree_symbol >> 1], \
bittree_symbol & 1); \
bittree_symbol >>= 1; \
} \
} while (0)
// Adds price to price_target.
#define bittree_reverse_get_price(price_target, probs, bit_levels, symbol) \
do { \
uint32_t model_index = 1; \
for (uint32_t bit_index = 0; bit_index < bit_levels; ++bit_index) { \
const uint32_t bit = ((symbol) >> bit_index) & 1; \
price_target += bit_get_price((probs)[model_index], bit); \
model_index = (model_index << 1) | bit; \
} \
} while (0)
//////////////////////
// Global variables //
//////////////////////
// Probability prices used by *_get_price() macros. This is initialized
// by lzma_rc_init() and is not modified later.
extern uint32_t lzma_rc_prob_prices[BIT_MODEL_TOTAL >> MOVE_REDUCING_BITS];
///////////////
// Functions //
///////////////
/// Initializes lzma_rc_prob_prices[]. This needs to be called only once.
extern void lzma_rc_init(void);
#ifdef RC_BUFFER_SIZE
/// Flushes data from rc->temp[] to out[] as much as possible. If everything
/// cannot be flushed, returns true; false otherwise.
static inline bool
rc_flush_buffer(lzma_range_encoder *rc,
uint8_t *out, size_t *out_pos, size_t out_size)
{
if (rc->buffer_size > 0) {
const size_t out_avail = out_size - *out_pos;
if (rc->buffer_size > out_avail) {
memcpy(out + *out_pos, rc->buffer, out_avail);
*out_pos += out_avail;
rc->buffer_size -= out_avail;
memmove(rc->buffer, rc->buffer + out_avail,
rc->buffer_size);
return true;
}
memcpy(out + *out_pos, rc->buffer, rc->buffer_size);
*out_pos += rc->buffer_size;
rc->buffer_size = 0;
}
return false;
}
#endif
#endif
