text: /*
  ** FAAD2 - Freeware Advanced Audio (AAC) Decoder including SBR decoding
  ** Copyright (C) 2003-2005 M. Bakker, Nero AG, http://www.nero.com
  **  
  ** 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  **
  ** Any non-GPL usage of this software or parts of this software is strictly
  ** forbidden.
  **
  ** The "appropriate copyright message" mentioned in section 2c of the GPLv2
  ** must read: "Code from FAAD2 is copyright (c) Nero AG, www.nero.com"
  **
  ** Commercial non-GPL licensing of this software is possible.
  ** For more info contact Nero AG through Mpeg4AAClicense@nero.com.
  **
  ** $Id: bits.c,v 1.44 2007/11/01 12:33:29 menno Exp $
  **/
  
  #include "common.h"
  #include "structs.h"
  
  #include <stdlib.h>
  #include "bits.h"
  
  /* initialize buffer, call once before first getbits or showbits */
  void faad_initbits(bitfile *ld, const void *_buffer, const uint32_t buffer_size)
  {
      uint32_t tmp;
  
      if (ld == NULL)
          return;
  
      // useless
      //memset(ld, 0, sizeof(bitfile));
  
      if (buffer_size == 0 || _buffer == NULL)
      {
          ld->error = 1;
          return;
      }
  
      ld->buffer = _buffer;
  
      ld->buffer_size = buffer_size;
      ld->bytes_left  = buffer_size;
  
      if (ld->bytes_left >= 4)
      {
          tmp = getdword((uint32_t*)ld->buffer);
          ld->bytes_left -= 4;
      } else {
          tmp = getdword_n((uint32_t*)ld->buffer, ld->bytes_left);
          ld->bytes_left = 0;
      }
      ld->bufa = tmp;
  
      if (ld->bytes_left >= 4)
      {
          tmp = getdword((uint32_t*)ld->buffer + 1);
          ld->bytes_left -= 4;
      } else {
          tmp = getdword_n((uint32_t*)ld->buffer + 1, ld->bytes_left);
          ld->bytes_left = 0;
      }
      ld->bufb = tmp;
  
      ld->start = (uint32_t*)ld->buffer;
      ld->tail = ((uint32_t*)ld->buffer + 2);
  
      ld->bits_left = 32;
  
      ld->error = 0;
  }
  
  void faad_endbits(bitfile *ld)
  {
      // void
  }
  
  uint32_t faad_get_processed_bits(bitfile *ld)
  {
      return (uint32_t)(8 * (4*(ld->tail - ld->start) - 4) - (ld->bits_left));
  }
  
  uint8_t faad_byte_align(bitfile *ld)
  {
      int remainder = (32 - ld->bits_left) & 0x7;
  
      if (remainder)
      {
          faad_flushbits(ld, 8 - remainder);
          return (uint8_t)(8 - remainder);
      }
      return 0;
  }
  
  void faad_flushbits_ex(bitfile *ld, uint32_t bits)
  {
      uint32_t tmp;
  
      ld->bufa = ld->bufb;
      if (ld->bytes_left >= 4)
      {
          tmp = getdword(ld->tail);
          ld->bytes_left -= 4;
      } else {
          tmp = getdword_n(ld->tail, ld->bytes_left);
          ld->bytes_left = 0;
      }
      ld->bufb = tmp;
      ld->tail++;
      ld->bits_left += (32 - bits);
      //ld->bytes_left -= 4;
  //    if (ld->bytes_left == 0)
  //        ld->no_more_reading = 1;
  //    if (ld->bytes_left < 0)
  //        ld->error = 1;
  }
  
  /* rewind to beginning */
  void faad_rewindbits(bitfile *ld)
  {
      uint32_t tmp;
  
      ld->bytes_left = ld->buffer_size;
  
      if (ld->bytes_left >= 4)
      {
          tmp = getdword((uint32_t*)&ld->start[0]);
          ld->bytes_left -= 4;
      } else {
          tmp = getdword_n((uint32_t*)&ld->start[0], ld->bytes_left);
          ld->bytes_left = 0;
      }
      ld->bufa = tmp;
  
      if (ld->bytes_left >= 4)
      {
          tmp = getdword((uint32_t*)&ld->start[1]);
          ld->bytes_left -= 4;
      } else {
          tmp = getdword_n((uint32_t*)&ld->start[1], ld->bytes_left);
          ld->bytes_left = 0;
      }
      ld->bufb = tmp;
  
      ld->bits_left = 32;
      ld->tail = &ld->start[2];
  }
  
  /* reset to a certain point */
  void faad_resetbits(bitfile *ld, int bits)
  {
      uint32_t tmp;
      int words = bits >> 5;
      int remainder = bits & 0x1F;
  
      ld->bytes_left = ld->buffer_size - words*4;
  
      if (ld->bytes_left >= 4)
      {
          tmp = getdword(&ld->start[words]);
          ld->bytes_left -= 4;
      } else {
          tmp = getdword_n(&ld->start[words], ld->bytes_left);
          ld->bytes_left = 0;
      }
      ld->bufa = tmp;
  
      if (ld->bytes_left >= 4)
      {
          tmp = getdword(&ld->start[words+1]);
          ld->bytes_left -= 4;
      } else {
          tmp = getdword_n(&ld->start[words+1], ld->bytes_left);
          ld->bytes_left = 0;
      }
      ld->bufb = tmp;
  
      ld->bits_left = 32 - remainder;
      ld->tail = &ld->start[words+2];
  
      /* recheck for reading too many bytes */
      ld->error = 0;
  //    if (ld->bytes_left == 0)
  //        ld->no_more_reading = 1;
  //    if (ld->bytes_left < 0)
  //        ld->error = 1;
  }
  
  uint8_t *faad_getbitbuffer(bitfile *ld, uint32_t bits
                         DEBUGDEC)
  {
      int i;
      unsigned int temp;
      int bytes = bits >> 3;
      int remainder = bits & 0x7;
  
      uint8_t *buffer = (uint8_t*)faad_malloc((bytes+1)*sizeof(uint8_t));
  
      for (i = 0; i < bytes; i++)
      {
          buffer[i] = (uint8_t)faad_getbits(ld, 8 DEBUGVAR(print,var,dbg));
      }
  
      if (remainder)
      {
          temp = faad_getbits(ld, remainder DEBUGVAR(print,var,dbg)) << (8-remainder);
  
          buffer[bytes] = (uint8_t)temp;
      }
  
      return buffer;
  }
  
  #ifdef DRM
  /* return the original data buffer */
  void *faad_origbitbuffer(bitfile *ld)
  {
      return (void*)ld->start;
  }
  
  /* return the original data buffer size */
  uint32_t faad_origbitbuffer_size(bitfile *ld)
  {
      return ld->buffer_size;
  }
  #endif
  
  /* reversed bit reading routines, used for RVLC and HCR */
  void faad_initbits_rev(bitfile *ld, void *buffer,
                         uint32_t bits_in_buffer)
  {
      uint32_t tmp;
      int32_t index;
  
      ld->buffer_size = bit2byte(bits_in_buffer);
  
      index = (bits_in_buffer+31)/32 - 1;
  
      ld->start = (uint32_t*)buffer + index - 2;
  
      tmp = getdword((uint32_t*)buffer + index);
      ld->bufa = tmp;
  
      tmp = getdword((uint32_t*)buffer + index - 1);
      ld->bufb = tmp;
  
      ld->tail = (uint32_t*)buffer + index;
  
      ld->bits_left = bits_in_buffer % 32;
      if (ld->bits_left == 0)
          ld->bits_left = 32;
  
      ld->bytes_left = ld->buffer_size;
      ld->error = 0;
  }
  
  /* EOF */
  