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range_enc.h
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162 lines (137 loc) · 3.77 KB
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/*
* Bitwise range encoder by Igor Pavlov
* Modified by Conor McCarthy
*
* Public domain
*/
#ifndef RANGE_ENCODER_H
#define RANGE_ENCODER_H
#include "mem.h"
#include "compiler.h"
#if defined (__cplusplus)
extern "C" {
#endif
#ifdef LZMA_ENC_PROB32
typedef U32 LZMA2_prob;
#else
typedef U16 LZMA2_prob;
#endif
#define kNumTopBits 24U
#define kTopValue (1UL << kNumTopBits)
#define kNumBitModelTotalBits 11U
#define kBitModelTotal (1 << kNumBitModelTotalBits)
#define kNumMoveBits 5U
#define kProbInitValue (kBitModelTotal >> 1U)
#define kNumMoveReducingBits 4U
#define kNumBitPriceShiftBits 5U
#define kPriceTableSize (kBitModelTotal >> kNumMoveReducingBits)
extern BYTE price_table[2][kPriceTableSize];
#if 0
void RC_printPriceTable();
#endif
typedef struct
{
BYTE *out_buffer;
size_t out_index;
U64 cache_size;
U64 low;
U32 range;
BYTE cache;
} RC_encoder;
void RC_reset(RC_encoder* const rc);
void RC_setOutputBuffer(RC_encoder* const rc, BYTE *const out_buffer);
void FORCE_NOINLINE RC_shiftLow(RC_encoder* const rc);
void RC_encodeBitTree(RC_encoder* const rc, LZMA2_prob *const probs, unsigned bit_count, unsigned symbol);
void RC_encodeBitTreeReverse(RC_encoder* const rc, LZMA2_prob *const probs, unsigned bit_count, unsigned symbol);
void FORCE_NOINLINE RC_encodeDirect(RC_encoder* const rc, unsigned value, unsigned bit_count);
HINT_INLINE
void RC_encodeBit0(RC_encoder* const rc, LZMA2_prob *const rprob)
{
unsigned prob = *rprob;
rc->range = (rc->range >> kNumBitModelTotalBits) * prob;
prob += (kBitModelTotal - prob) >> kNumMoveBits;
*rprob = (LZMA2_prob)prob;
if (rc->range < kTopValue) {
rc->range <<= 8;
RC_shiftLow(rc);
}
}
HINT_INLINE
void RC_encodeBit1(RC_encoder* const rc, LZMA2_prob *const rprob)
{
unsigned prob = *rprob;
U32 new_bound = (rc->range >> kNumBitModelTotalBits) * prob;
rc->low += new_bound;
rc->range -= new_bound;
prob -= prob >> kNumMoveBits;
*rprob = (LZMA2_prob)prob;
if (rc->range < kTopValue) {
rc->range <<= 8;
RC_shiftLow(rc);
}
}
HINT_INLINE
void RC_encodeBit(RC_encoder* const rc, LZMA2_prob *const rprob, unsigned const bit)
{
unsigned prob = *rprob;
if (bit != 0) {
U32 const new_bound = (rc->range >> kNumBitModelTotalBits) * prob;
rc->low += new_bound;
rc->range -= new_bound;
prob -= prob >> kNumMoveBits;
}
else {
rc->range = (rc->range >> kNumBitModelTotalBits) * prob;
prob += (kBitModelTotal - prob) >> kNumMoveBits;
}
*rprob = (LZM
6690
A2_prob)prob;
if (rc->range < kTopValue) {
rc->range <<= 8;
RC_shiftLow(rc);
}
}
#define GET_PRICE(prob, symbol) \
price_table[symbol][(prob) >> kNumMoveReducingBits]
#define GET_PRICE_0(prob) price_table[0][(prob) >> kNumMoveReducingBits]
#define GET_PRICE_1(prob) price_table[1][(prob) >> kNumMoveReducingBits]
#define kMinLitPrice 8U
HINT_INLINE
unsigned RC_getTreePrice(const LZMA2_prob* const prob_table, unsigned bit_count, size_t symbol)
{
unsigned price = 0;
symbol |= ((size_t)1 << bit_count);
do {
size_t const next_symbol = symbol >> 1;
unsigned prob = prob_table[next_symbol];
size_t bit = symbol & 1;
price += GET_PRICE(prob, bit);
symbol = next_symbol;
} while (symbol != 1);
return price;
}
HINT_INLINE
unsigned RC_getReverseTreePrice(const LZMA2_prob* const prob_table, unsigned bit_count, size_t symbol)
{
unsigned prob = prob_table[1];
size_t bit = symbol & 1;
unsigned price = GET_PRICE(prob, bit);
size_t m = 1;
while (--bit_count != 0) {
m = (m << 1) | bit;
symbol >>= 1;
prob = prob_table[m];
bit = symbol & 1;
price += GET_PRICE(prob, bit);
}
return price;
}
HINT_INLINE
void RC_flush(RC_encoder* const rc)
{
for (int i = 0; i < 5; ++i)
RC_shiftLow(rc);
}
#if defined (__cplusplus)
}
#endif
#endif /* RANGE_ENCODER_H */