• 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 1994-2009             *
     * by the Xiph.Org Foundation https://xiph.org/                     *
     *                                                                  *
     ********************************************************************
    
     function: modified discrete cosine transform prototypes
    
     ********************************************************************/
    
    #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