/*
  * 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 "mathops.h"

 #include "config.h"

 
 //#define ALT_BITSTREAM_WRITER
 //#define ALIGNED_BITSTREAM_WRITER
 
 /* buf and buf_end must be present and used by every alternative writer. */
 typedef struct PutBitContext {
 #ifdef ALT_BITSTREAM_WRITER
     uint8_t *buf, *buf_end;
     int index;
 #else
     uint32_t bit_buf;
     int bit_left;
     uint8_t *buf, *buf_ptr, *buf_end;
 #endif
     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;
 #ifdef ALT_BITSTREAM_WRITER
     s->index=0;
     ((uint32_t*)(s->buf))[0]=0;
 //    memset(buffer, 0, buffer_size);
 #else
     s->buf_ptr = s->buf;
     s->bit_left=32;
     s->bit_buf=0;
 #endif
 }
 
 /**

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

  */
 static inline int put_bits_count(PutBitContext *s)
 {
 #ifdef ALT_BITSTREAM_WRITER
     return s->index;
 #else
     return (s->buf_ptr - s->buf) * 8 + 32 - s->bit_left;
 #endif
 }
 
 /**

  * Pad the end of the output stream with zeros.

  */
 static inline void flush_put_bits(PutBitContext *s)
 {
 #ifdef ALT_BITSTREAM_WRITER
     align_put_bits(s);
 #else
 #ifndef BITSTREAM_WRITER_LE
     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;
 #endif
 }
 

 #if defined(ALT_BITSTREAM_WRITER) || defined(BITSTREAM_WRITER_LE)
 #define align_put_bits align_put_bits_unsupported_here
 #define ff_put_string ff_put_string_unsupported_here
 #define ff_copy_bits ff_copy_bits_unsupported_here
 #else

 /**

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

  */
 void 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 ff_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 ff_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)
 #ifndef ALT_BITSTREAM_WRITER
 {
     unsigned int bit_buf;
     int bit_left;
 
     //    printf("put_bits=%d %x\n", n, value);

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

 
     bit_buf = s->bit_buf;
     bit_left = s->bit_left;
 
     //    printf("n=%d value=%x cnt=%d buf=%x\n", n, value, bit_cnt, bit_buf);
     /* XXX: optimize */
 #ifdef BITSTREAM_WRITER_LE
     bit_buf |= value << (32 - bit_left);
     if (n >= bit_left) {
 #if !HAVE_FAST_UNALIGNED
         if (3 & (intptr_t) s->buf_ptr) {
             AV_WL32(s->buf_ptr, bit_buf);
         } else
 #endif

         *(uint32_t *)s->buf_ptr = av_le2ne32(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);
 #if !HAVE_FAST_UNALIGNED
         if (3 & (intptr_t) s->buf_ptr) {
             AV_WB32(s->buf_ptr, bit_buf);
         } else
 #endif

         *(uint32_t *)s->buf_ptr = av_be2ne32(bit_buf);

         //printf("bitbuf = %08x\n", bit_buf);
         s->buf_ptr+=4;
         bit_left+=32 - n;
         bit_buf = value;
     }
 #endif
 
     s->bit_buf = bit_buf;
     s->bit_left = bit_left;
 }
 #else  /* ALT_BITSTREAM_WRITER defined */
 {
 #    ifdef ALIGNED_BITSTREAM_WRITER
 #        if ARCH_X86
     __asm__ volatile(
         "movl %0, %%ecx                 \n\t"
         "xorl %%eax, %%eax              \n\t"
         "shrdl %%cl, %1, %%eax          \n\t"
         "shrl %%cl, %1                  \n\t"
         "movl %0, %%ecx                 \n\t"
         "shrl $3, %%ecx                 \n\t"
         "andl $0xFFFFFFFC, %%ecx        \n\t"
         "bswapl %1                      \n\t"
         "orl %1, (%2, %%ecx)            \n\t"
         "bswapl %%eax                   \n\t"
         "addl %3, %0                    \n\t"
         "movl %%eax, 4(%2, %%ecx)       \n\t"
         : "=&r" (s->index), "=&r" (value)
         : "r" (s->buf), "r" (n), "0" (s->index), "1" (value<<(-n))
         : "%eax", "%ecx"
     );
 #        else
     int index= s->index;
     uint32_t *ptr= ((uint32_t *)s->buf)+(index>>5);
 
     value<<= 32-n;
 

     ptr[0] |= av_be2ne32(value>>(index&31));
     ptr[1]  = av_be2ne32(value<<(32-(index&31)));

 //if(n>24) printf("%d %d\n", n, value);
     index+= n;
     s->index= index;
 #        endif
 #    else //ALIGNED_BITSTREAM_WRITER
 #        if ARCH_X86
     __asm__ volatile(
         "movl $7, %%ecx                 \n\t"
         "andl %0, %%ecx                 \n\t"
         "addl %3, %%ecx                 \n\t"
         "negl %%ecx                     \n\t"
         "shll %%cl, %1                  \n\t"
         "bswapl %1                      \n\t"
         "movl %0, %%ecx                 \n\t"
         "shrl $3, %%ecx                 \n\t"
         "orl %1, (%%ecx, %2)            \n\t"
         "addl %3, %0                    \n\t"
         "movl $0, 4(%%ecx, %2)          \n\t"
         : "=&r" (s->index), "=&r" (value)
         : "r" (s->buf), "r" (n), "0" (s->index), "1" (value)
         : "%ecx"
     );
 #        else
     int index= s->index;
     uint32_t *ptr= (uint32_t*)(((uint8_t *)s->buf)+(index>>3));
 

     ptr[0] |= av_be2ne32(value<<(32-n-(index&7) ));

     ptr[1] = 0;
 //if(n>24) printf("%d %d\n", n, value);
     index+= n;
     s->index= index;
 #        endif
 #    endif //!ALIGNED_BITSTREAM_WRITER
 }
 #endif
 

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

 {

     assert(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)

 {
 #ifdef ALT_BITSTREAM_WRITER
         return s->buf + (s->index>>3);
 #else
         return s->buf_ptr;
 #endif
 }
 
 /**

  * 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)
 {

         assert((put_bits_count(s)&7)==0);
 #ifdef ALT_BITSTREAM_WRITER
         FIXME may need some cleaning of the buffer
         s->index += n<<3;
 #else
         assert(s->bit_left==32);
         s->buf_ptr += n;
 #endif
 }
 
 /**

  * 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)
 {

 #ifdef ALT_BITSTREAM_WRITER
     s->index += n;
 #else
     s->bit_left -= n;

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

     s->bit_left &= 31;
 #endif
 }
 
 /**

  * 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 */