apps/codecs/libtremor/window.c

   1 /********************************************************************
   2  *                                                                  *
   3  * THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE.   *
   4  *                                                                  *
   5  * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
   6  * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
   7  * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
   8  *                                                                  *
   9  * THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2002    *
  10  * BY THE Xiph.Org FOUNDATION http://www.xiph.org/                  *
  11  *                                                                  *
  12  ********************************************************************
  13
  14  function: window functions
  15
  16  ********************************************************************/
  17
  18 #include "config-tremor.h"
  19 #include <string.h>
  20 #include <math.h>
  21 #include "os.h"
  22 #include "misc.h"
  23 #include "window.h"
  24 #include "window_lookup.h"
  25
  26 const void *_vorbis_window(int type, int left){
  27
  28   switch(type){
  29   case 0:
  30
  31     switch(left){
  32     case 32:
  33       return vwin64;
  34     case 64:
  35       return vwin128;
  36     case 128:
  37       return vwin256;
  38     case 256:
  39       return vwin512;
  40     case 512:
  41       return vwin1024;
  42     case 1024:
  43       return vwin2048;
  44     case 2048:
  45       return vwin4096;
  46     case 4096:
  47       return vwin8192;
  48     default:
  49       return(0);
  50     }
  51     break;
  52   default:
  53     return(0);
  54   }
  55 }
  56
  57 void _vorbis_apply_window(ogg_int32_t *d,const void *window_p[2],
  58                           long *blocksizes,
  59                           int lW,int W,int nW){
  60   LOOKUP_T *window[2]={window_p[0],window_p[1]};
  61   long n=blocksizes[W];
  62   long ln=blocksizes[lW];
  63   long rn=blocksizes[nW];
  64
  65   long leftbegin=n/4-ln/4;
  66   long leftend=leftbegin+ln/2;
  67
  68   long rightbegin=n/2+n/4-rn/4;
  69   long rightend=rightbegin+rn/2;
  70
  71   memset((void *)&d[0], 0, sizeof(ogg_int32_t)*leftbegin);
  72   /* mcf5249_vect_zero(&d[0], leftbegin); */
  73   vect_mult_fw(&d[leftbegin], &window[lW][0], leftend-leftbegin);
  74   vect_mult_bw(&d[rightbegin], &window[nW][rn/2-1], rightend-rightbegin);
  75   memset((void *)&d[rightend], 0, sizeof(ogg_int32_t)*(n-rightend));
  76   /* mcf5249_vect_zero(&d[rightend], n-rightend); */
  77 }
  78