libbpg/x265/source/common/bitstream.h
2015-10-27 11:46:00 +01:00

158 lines
5.5 KiB
C++

/*****************************************************************************
* Copyright (C) 2013 x265 project
*
* Author: Steve Borho <steve@borho.org>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02111, USA.
*
* This program is also available under a commercial proprietary license.
* For more information, contact us at license @ x265.com.
*****************************************************************************/
#ifndef X265_BITSTREAM_H
#define X265_BITSTREAM_H 1
namespace X265_NS {
// private namespace
class BitInterface
{
public:
virtual void write(uint32_t val, uint32_t numBits) = 0;
virtual void writeByte(uint32_t val) = 0;
virtual void resetBits() = 0;
virtual uint32_t getNumberOfWrittenBits() const = 0;
virtual void writeAlignOne() = 0;
virtual void writeAlignZero() = 0;
virtual ~BitInterface() {}
};
class BitCounter : public BitInterface
{
protected:
uint32_t m_bitCounter;
public:
BitCounter() : m_bitCounter(0) {}
void write(uint32_t, uint32_t num) { m_bitCounter += num; }
void writeByte(uint32_t) { m_bitCounter += 8; }
void resetBits() { m_bitCounter = 0; }
uint32_t getNumberOfWrittenBits() const { return m_bitCounter; }
void writeAlignOne() { }
void writeAlignZero() { }
};
class Bitstream : public BitInterface
{
public:
Bitstream();
~Bitstream() { X265_FREE(m_fifo); }
void resetBits() { m_partialByteBits = m_byteOccupancy = 0; m_partialByte = 0; }
uint32_t getNumberOfWrittenBytes() const { return m_byteOccupancy; }
uint32_t getNumberOfWrittenBits() const { return m_byteOccupancy * 8 + m_partialByteBits; }
const uint8_t* getFIFO() const { return m_fifo; }
void write(uint32_t val, uint32_t numBits);
void writeByte(uint32_t val);
void writeAlignOne(); // insert one bits until the bitstream is byte-aligned
void writeAlignZero(); // insert zero bits until the bitstream is byte-aligned
void writeByteAlignment(); // insert 1 bit, then pad to byte-align with zero
private:
uint8_t *m_fifo;
uint32_t m_byteAlloc;
uint32_t m_byteOccupancy;
uint32_t m_partialByteBits;
uint8_t m_partialByte;
void push_back(uint8_t val);
};
static const uint8_t bitSize[256] =
{
1, 1, 3, 3, 5, 5, 5, 5, 7, 7, 7, 7, 7, 7, 7, 7,
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9,
11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11,
11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11,
13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13,
13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13,
13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13,
13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
};
static inline int bs_size_ue(unsigned int val)
{
return bitSize[val + 1];
}
static inline int bs_size_ue_big(unsigned int val)
{
if (val < 255)
return bitSize[val + 1];
else
return bitSize[(val + 1) >> 8] + 16;
}
static inline int bs_size_se(int val)
{
int tmp = 1 - val * 2;
if (tmp < 0) tmp = val * 2;
if (tmp < 256)
return bitSize[tmp];
else
return bitSize[tmp >> 8] + 16;
}
class SyntaxElementWriter
{
public:
BitInterface* m_bitIf;
SyntaxElementWriter() : m_bitIf(NULL) {}
/* silently discard the name of the syntax element */
inline void WRITE_CODE(uint32_t code, uint32_t length, const char *) { writeCode(code, length); }
inline void WRITE_UVLC(uint32_t code, const char *) { writeUvlc(code); }
inline void WRITE_SVLC(int32_t code, const char *) { writeSvlc(code); }
inline void WRITE_FLAG(bool flag, const char *) { writeFlag(flag); }
void writeCode(uint32_t code, uint32_t length) { m_bitIf->write(code, length); }
void writeUvlc(uint32_t code);
void writeSvlc(int32_t code) { uint32_t ucode = (code <= 0) ? -code << 1 : (code << 1) - 1; writeUvlc(ucode); }
void writeFlag(bool code) { m_bitIf->write(code, 1); }
};
}
#endif // ifndef X265_BITSTREAM_H