/*
  * 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;
     }
 }