/*
  * copyright (c) 2004 Michael Niedermayer <michaelni@gmx.at>
  *
  * 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 <stdint.h>
 #include <stdlib.h>
 #include <assert.h>

 #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+3<s->buf_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+3<s->buf_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 */