ref: a57a6e511f15c02b4fd2690197b6f1333b171193
dir: /sys/src/cmd/audio/libvorbis/mdct.h/
/********************************************************************
* *
* 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"
/*#define MDCT_INTEGERIZED <- be warned there could be some hurt left here*/
#ifdef MDCT_INTEGERIZED
#define DATA_TYPE int
#define REG_TYPE register int
#define TRIGBITS 14
#define cPI3_8 6270
#define cPI2_8 11585
#define cPI1_8 15137
#define FLOAT_CONV(x) ((int)((x)*(1<<TRIGBITS)+.5))
#define MULT_NORM(x) ((x)>>TRIGBITS)
#define HALVE(x) ((x)>>1)
#else
#define DATA_TYPE float
#define REG_TYPE float
#define cPI3_8 .38268343236508977175F
#define cPI2_8 .70710678118654752441F
#define cPI1_8 .92387953251128675613F
#define FLOAT_CONV(x) (x)
#define MULT_NORM(x) (x)
#define HALVE(x) ((x)*.5f)
#endif
typedef struct {
int n;
int log2n;
DATA_TYPE *trig;
int *bitrev;
DATA_TYPE scale;
} mdct_lookup;
extern void mdct_init(mdct_lookup *lookup,int n);
extern void mdct_clear(mdct_lookup *l);
extern void mdct_forward(mdct_lookup *init, DATA_TYPE *in, DATA_TYPE *out);
extern void mdct_backward(mdct_lookup *init, DATA_TYPE *in, DATA_TYPE *out);
#endif