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 
15  ********************************************************************/
16 
17 #ifndef _OGG_mdct_H_
18 #define _OGG_mdct_H_
19 
20 #include "vorbis/codec.h"
21 
22 
23 
24 
25 
26 /*#define MDCT_INTEGERIZED  <- be warned there could be some hurt left here*/
27 #ifdef MDCT_INTEGERIZED
28 
29 #define DATA_TYPE int
30 #define REG_TYPE  register int
31 #define TRIGBITS 14
32 #define cPI3_8 6270
33 #define cPI2_8 11585
34 #define cPI1_8 15137
35 
36 #define FLOAT_CONV(x) ((int)((x)*(1<<TRIGBITS)+.5))
37 #define MULT_NORM(x) ((x)>>TRIGBITS)
38 #define HALVE(x) ((x)>>1)
39 
40 #else
41 
42 #define DATA_TYPE float
43 #define REG_TYPE  float
44 #define cPI3_8 .38268343236508977175F
45 #define cPI2_8 .70710678118654752441F
46 #define cPI1_8 .92387953251128675613F
47 
48 #define FLOAT_CONV(x) (x)
49 #define MULT_NORM(x) (x)
50 #define HALVE(x) ((x)*.5f)
51 
52 #endif
53 
54 
55 typedef struct {
56   int n;
57   int log2n;
58 
59   DATA_TYPE *trig;
60   int       *bitrev;
61 
62   DATA_TYPE scale;
63 } mdct_lookup;
64 
65 extern void mdct_init(mdct_lookup *lookup,int n);
66 extern void mdct_clear(mdct_lookup *l);
67 extern void mdct_forward(mdct_lookup *init, DATA_TYPE *in, DATA_TYPE *out);
68 extern void mdct_backward(mdct_lookup *init, DATA_TYPE *in, DATA_TYPE *out);
69 
70 #endif
71