1 /********************************************************************
2  *                                                                  *
3  * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
4  * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
5  * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
6  * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
7  *                                                                  *
8  * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2009             *
9  * by the Xiph.Org Foundation http://www.xiph.org/                  *
10  *                                                                  *
11  ********************************************************************
12 
13  function: modified discrete cosine transform prototypes
14  last mod: $Id: mdct.h 16227 2009-07-08 06:58:46Z xiphmont $
15 
16  ********************************************************************/
17 
18 #ifndef _OGG_mdct_H_
19 #define _OGG_mdct_H_
20 
21 #include "vorbis/codec.h"
22 
23 
24 
25 
26 
27 /*#define MDCT_INTEGERIZED  <- be warned there could be some hurt left here*/
28 #ifdef MDCT_INTEGERIZED
29 
30 #define DATA_TYPE int
31 #define REG_TYPE  register int
32 #define TRIGBITS 14
33 #define cPI3_8 6270
34 #define cPI2_8 11585
35 #define cPI1_8 15137
36 
37 #define FLOAT_CONV(x) ((int)((x)*(1<<TRIGBITS)+.5))
38 #define MULT_NORM(x) ((x)>>TRIGBITS)
39 #define HALVE(x) ((x)>>1)
40 
41 #else
42 
43 #define DATA_TYPE float
44 #define REG_TYPE  float
45 #define cPI3_8 .38268343236508977175F
46 #define cPI2_8 .70710678118654752441F
47 #define cPI1_8 .92387953251128675613F
48 
49 #define FLOAT_CONV(x) (x)
50 #define MULT_NORM(x) (x)
51 #define HALVE(x) ((x)*.5f)
52 
53 #endif
54 
55 
56 typedef struct {
57   int n;
58   int log2n;
59 
60   DATA_TYPE *trig;
61   int       *bitrev;
62 
63   DATA_TYPE scale;
64 } mdct_lookup;
65 
66 extern void mdct_init(mdct_lookup *lookup,int n);
67 extern void mdct_clear(mdct_lookup *l);
68 extern void mdct_forward(mdct_lookup *init, DATA_TYPE *in, DATA_TYPE *out);
69 extern void mdct_backward(mdct_lookup *init, DATA_TYPE *in, DATA_TYPE *out);
70 
71 #endif
72