Subversion Repositories Kolibri OS

/*

 * copyright (c) 2004 Michael Niedermayer 

 *

 * This file is part of FFmpeg.

 *

 * FFmpeg 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.

 *

 * FFmpeg 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.

 *

 * You should have received a copy of the GNU Lesser General Public

 * License along with FFmpeg; if not, write to the Free Software

 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA

 */

/**

 * @file

 * bitstream writer API

 */

#ifndef AVCODEC_PUT_BITS_H

#define AVCODEC_PUT_BITS_H

#include 

#include 

#include 

#include "libavutil/bswap.h"

#include "libavutil/common.h"

#include "libavutil/intreadwrite.h"

#include "libavutil/log.h"

#include "libavutil/avassert.h"

#include "mathops.h"

#include "config.h"

typedef struct PutBitContext {

    uint32_t bit_buf;

    int bit_left;

    uint8_t *buf, *buf_ptr, *buf_end;

    int size_in_bits;

} PutBitContext;

/**

 * Initialize the PutBitContext s.

 *

 * @param buffer the buffer where to put bits

 * @param buffer_size the size in bytes of buffer

 */

static inline void init_put_bits(PutBitContext *s, uint8_t *buffer,

                                 int buffer_size)

{

    if (buffer_size < 0) {

        buffer_size = 0;

        buffer      = NULL;

    }

    s->size_in_bits = 8 * buffer_size;

    s->buf          = buffer;

    s->buf_end      = s->buf + buffer_size;

    s->buf_ptr      = s->buf;

    s->bit_left     = 32;

    s->bit_buf      = 0;

}

/**

 * @return the total number of bits written to the bitstream.

 */

static inline int put_bits_count(PutBitContext *s)

{

    return (s->buf_ptr - s->buf) * 8 + 32 - s->bit_left;

}

/**

 * @return the number of bits available in the bitstream.

 */

static inline int put_bits_left(PutBitContext* s)

{

    return (s->buf_end - s->buf_ptr) * 8 - 32 + s->bit_left;

}

/**

 * Pad the end of the output stream with zeros.

 */

static inline void flush_put_bits(PutBitContext *s)

{

#ifndef BITSTREAM_WRITER_LE

    if (s->bit_left < 32)

        s->bit_buf <<= s->bit_left;

#endif

    while (s->bit_left < 32) {

        /* XXX: should test end of buffer */

#ifdef BITSTREAM_WRITER_LE

        *s->buf_ptr++ = s->bit_buf;

        s->bit_buf  >>= 8;

#else

        *s->buf_ptr++ = s->bit_buf >> 24;

        s->bit_buf  <<= 8;

#endif

        s->bit_left  += 8;

    }

    s->bit_left = 32;

    s->bit_buf  = 0;

}

#ifdef BITSTREAM_WRITER_LE

#define avpriv_align_put_bits align_put_bits_unsupported_here

#define avpriv_put_string ff_put_string_unsupported_here

#define avpriv_copy_bits avpriv_copy_bits_unsupported_here

#else

/**

 * Pad the bitstream with zeros up to the next byte boundary.

 */

void avpriv_align_put_bits(PutBitContext *s);

/**

 * Put the string string in the bitstream.

 *

 * @param terminate_string 0-terminates the written string if value is 1

 */

void avpriv_put_string(PutBitContext *pb, const char *string,

                       int terminate_string);

/**

 * Copy the content of src to the bitstream.

 *

 * @param length the number of bits of src to copy

 */

void avpriv_copy_bits(PutBitContext *pb, const uint8_t *src, int length);

#endif

/**

 * Write up to 31 bits into a bitstream.

 * Use put_bits32 to write 32 bits.

 */

static inline void put_bits(PutBitContext *s, int n, unsigned int value)

{

    unsigned int bit_buf;

    int bit_left;

    av_assert2(n <= 31 && value < (1U << n));

    bit_buf  = s->bit_buf;

    bit_left = s->bit_left;

    /* XXX: optimize */

#ifdef BITSTREAM_WRITER_LE

    bit_buf |= value << (32 - bit_left);

    if (n >= bit_left) {

        av_assert2(s->buf_ptr+3buf_end);

        AV_WL32(s->buf_ptr, bit_buf);

        s->buf_ptr += 4;

        bit_buf     = (bit_left == 32) ? 0 : value >> bit_left;

        bit_left   += 32;

    }

    bit_left -= n;

#else

    if (n < bit_left) {

        bit_buf     = (bit_buf << n) | value;

        bit_left   -= n;

    } else {

        bit_buf   <<= bit_left;

        bit_buf    |= value >> (n - bit_left);

        av_assert2(s->buf_ptr+3buf_end);

        AV_WB32(s->buf_ptr, bit_buf);

        s->buf_ptr += 4;

        bit_left   += 32 - n;

        bit_buf     = value;

    }

#endif

    s->bit_buf  = bit_buf;

    s->bit_left = bit_left;

}

static inline void put_sbits(PutBitContext *pb, int n, int32_t value)

{

    av_assert2(n >= 0 && n <= 31);

    put_bits(pb, n, value & ((1 << n) - 1));

}

/**

 * Write exactly 32 bits into a bitstream.

 */

static void av_unused put_bits32(PutBitContext *s, uint32_t value)

{

    int lo = value & 0xffff;

    int hi = value >> 16;

#ifdef BITSTREAM_WRITER_LE

    put_bits(s, 16, lo);

    put_bits(s, 16, hi);

#else

    put_bits(s, 16, hi);

    put_bits(s, 16, lo);

#endif

}

/**

 * Return the pointer to the byte where the bitstream writer will put

 * the next bit.

 */

static inline uint8_t *put_bits_ptr(PutBitContext *s)

{

    return s->buf_ptr;

}

/**

 * Skip the given number of bytes.

 * PutBitContext must be flushed & aligned to a byte boundary before calling this.

 */

static inline void skip_put_bytes(PutBitContext *s, int n)

{

    av_assert2((put_bits_count(s) & 7) == 0);

    av_assert2(s->bit_left == 32);

    s->buf_ptr += n;

}

/**

 * Skip the given number of bits.

 * Must only be used if the actual values in the bitstream do not matter.

 * If n is 0 the behavior is undefined.

 */

static inline void skip_put_bits(PutBitContext *s, int n)

{

    s->bit_left -= n;

    s->buf_ptr  -= 4 * (s->bit_left >> 5);

    s->bit_left &= 31;

}

/**

 * Change the end of the buffer.

 *

 * @param size the new size in bytes of the buffer where to put bits

 */

static inline void set_put_bits_buffer_size(PutBitContext *s, int size)

{

    s->buf_end = s->buf + size;

}

#endif /* AVCODEC_PUT_BITS_H */