text: /*
   * Lagarith range decoder
   * Copyright (c) 2009 Nathan Caldwell <saintdev (at) gmail.com>
   * Copyright (c) 2009 David Conrad
   *
   * 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
   * Lagarith range decoder
   * @author Nathan Caldwell
   * @author David Conrad
   */
  
  #include "get_bits.h"
  #include "lagarithrac.h"
  
  void ff_lag_rac_init(lag_rac *l, GetBitContext *gb, int length)
  {
      int i, j, left;
  
      /* According to reference decoder "1st byte is garbage",
       * however, it gets skipped by the call to align_get_bits()
       */
      align_get_bits(gb);
      left                = get_bits_left(gb) >> 3;
      l->bytestream_start =
      l->bytestream       = gb->buffer + get_bits_count(gb) / 8;
      l->bytestream_end   = l->bytestream_start + left;
  
      l->range        = 0x80;
      l->low          = *l->bytestream >> 1;
      l->hash_shift   = FFMAX(l->scale, 10) - 10;
      l->overread     = 0;
  
      for (i = j = 0; i < 1024; i++) {
          unsigned r = i << l->hash_shift;
          while (l->prob[j + 1] <= r)
              j++;
          l->range_hash[i] = j;
      }
  }
  