michael@0: /********************************************************************
michael@0:  *                                                                  *
michael@0:  * THIS FILE IS PART OF THE OggVorbis 'TREMOR' CODEC SOURCE CODE.   *
michael@0:  *                                                                  *
michael@0:  * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
michael@0:  * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
michael@0:  * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
michael@0:  *                                                                  *
michael@0:  * THE OggVorbis 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2002    *
michael@0:  * BY THE Xiph.Org FOUNDATION http://www.xiph.org/                  *
michael@0:  *                                                                  *
michael@0:  ********************************************************************
michael@0: 
michael@0:  function: window functions
michael@0: 
michael@0:  ********************************************************************/
michael@0: 
michael@0: #include <stdlib.h>
michael@0: #include <math.h>
michael@0: #include "misc.h"
michael@0: #include "window.h"
michael@0: #include "window_lookup.h"
michael@0: 
michael@0: const void *_vorbis_window(int type, int left){
michael@0: 
michael@0:   switch(type){
michael@0:   case 0:
michael@0: 
michael@0:     switch(left){
michael@0:     case 32:
michael@0:       return vwin64;
michael@0:     case 64:
michael@0:       return vwin128;
michael@0:     case 128:
michael@0:       return vwin256;
michael@0:     case 256:
michael@0:       return vwin512;
michael@0:     case 512:
michael@0:       return vwin1024;
michael@0:     case 1024:
michael@0:       return vwin2048;
michael@0:     case 2048:
michael@0:       return vwin4096;
michael@0:     case 4096:
michael@0:       return vwin8192;
michael@0:     default:
michael@0:       return(0);
michael@0:     }
michael@0:     break;
michael@0:   default:
michael@0:     return(0);
michael@0:   }
michael@0: }
michael@0: 
michael@0: void _vorbis_apply_window(ogg_int32_t *d,const void *window_p[2],
michael@0: 			  long *blocksizes,
michael@0: 			  int lW,int W,int nW){
michael@0:   
michael@0:   LOOKUP_T *window[2]={window_p[0],window_p[1]};
michael@0:   long n=blocksizes[W];
michael@0:   long ln=blocksizes[lW];
michael@0:   long rn=blocksizes[nW];
michael@0: 
michael@0:   long leftbegin=n/4-ln/4;
michael@0:   long leftend=leftbegin+ln/2;
michael@0: 
michael@0:   long rightbegin=n/2+n/4-rn/4;
michael@0:   long rightend=rightbegin+rn/2;
michael@0:   
michael@0:   int i,p;
michael@0: 
michael@0:   for(i=0;i<leftbegin;i++)
michael@0:     d[i]=0;
michael@0: 
michael@0:   for(p=0;i<leftend;i++,p++)
michael@0:     d[i]=MULT31(d[i],window[lW][p]);
michael@0: 
michael@0:   for(i=rightbegin,p=rn/2-1;i<rightend;i++,p--)
michael@0:     d[i]=MULT31(d[i],window[nW][p]);
michael@0: 
michael@0:   for(;i<n;i++)
michael@0:     d[i]=0;
michael@0: }