mdct.h

fix point版本的Ogg Vorbis decoder

/********************************************************************
 *                                                                  *
 * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
 * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
 * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
 * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
 *                                                                  *
 * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2002             *
 * by the XIPHOPHORUS Company http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

 function: modified discrete cosine transform prototypes
 last mod: $Id: mdct.h,v 1.20 2002/01/22 11:59:00 xiphmont Exp $

 ********************************************************************/

#ifndef _OGG_mdct_H_
#define _OGG_mdct_H_

#include "vorbis_codec.h"

typedef struct {
  int n;
  int log2n;
  
  FIXP *trig;
  int  *bitrev;

  FIXP  scale;
} mdct_lookup;

extern void mdct_init(mdct_lookup *lookup,int n);
extern void mdct_clear(mdct_lookup *l);
extern void mdct_backward(mdct_lookup *init, FIXP *in, FIXP *out);

#endif