/* MPEG/WAVE Sound library

   (C) 1997 by Jung woo-jae */

// Bitwindow.cc
// It's bit reservior for MPEG layer 3

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

#include "mpegsound.h"

#ifndef WORDS_BIGENDIAN
#define _KEY 0
#else
#define _KEY 3
#endif

int Mpegbitwindow::getbits(int bits)
{
  union
  {
    char store[4];
    int current;
  }u;

  int bi;

  if( !bits ) return 0;

  u.current = 0;

  bi = ( bitindex & 7 );

  //  u.store[_KEY]=buffer[(bitindex>>3)&(WINDOWSIZE-1)]<<bi;
  u.store[_KEY] = buffer[ bitindex >> 3 ] << bi;

  bi = 8 - bi;

  bitindex += bi;

  while(bits)
  {
    if(!bi)
    {
      //      u.store[_KEY]=buffer[(bitindex>>3)&(WINDOWSIZE-1)];
      u.store[_KEY] = buffer[ bitindex >> 3 ];
      bitindex += 8;
      bi = 8;
    }

    if( bits >= bi )
    {
      u.current <<= bi;
      bits -= bi;
      bi = 0;
    }
    else
    {
      u.current <<= bits;
      bi -= bits;
      bits = 0;
    }
  }

  bitindex -= bi;

  return ( u.current >> 8 );
}