Line data    Source code

       1             : /*
       2             :  *  Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
       3             :  *
       4             :  *  Use of this source code is governed by a BSD-style license
       5             :  *  that can be found in the LICENSE file in the root of the source
       6             :  *  tree. An additional intellectual property rights grant can be found
       7             :  *  in the file PATENTS.  All contributing project authors may
       8             :  *  be found in the AUTHORS file in the root of the source tree.
       9             :  */
      10             : 
      11             : 
      12             : /*
      13             :  * This file contains the function WebRtcSpl_GetHanningWindow().
      14             :  * The description header can be found in signal_processing_library.h
      15             :  *
      16             :  */
      17             : 
      18             : #include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
      19             : 
      20             : // Hanning table with 256 entries
      21             : static const int16_t kHanningTable[] = {
      22             :     1,      2,      6,     10,     15,     22,     30,     39,
      23             :    50,     62,     75,     89,    104,    121,    138,    157,
      24             :   178,    199,    222,    246,    271,    297,    324,    353,
      25             :   383,    413,    446,    479,    513,    549,    586,    624,
      26             :   663,    703,    744,    787,    830,    875,    920,    967,
      27             :  1015,   1064,   1114,   1165,   1218,   1271,   1325,   1381,
      28             :  1437,   1494,   1553,   1612,   1673,   1734,   1796,   1859,
      29             :  1924,   1989,   2055,   2122,   2190,   2259,   2329,   2399,
      30             :  2471,   2543,   2617,   2691,   2765,   2841,   2918,   2995,
      31             :  3073,   3152,   3232,   3312,   3393,   3475,   3558,   3641,
      32             :  3725,   3809,   3895,   3980,   4067,   4154,   4242,   4330,
      33             :  4419,   4509,   4599,   4689,   4781,   4872,   4964,   5057,
      34             :  5150,   5244,   5338,   5432,   5527,   5622,   5718,   5814,
      35             :  5910,   6007,   6104,   6202,   6299,   6397,   6495,   6594,
      36             :  6693,   6791,   6891,   6990,   7090,   7189,   7289,   7389,
      37             :  7489,   7589,   7690,   7790,   7890,   7991,   8091,   8192,
      38             :  8293,   8393,   8494,   8594,   8694,   8795,   8895,   8995,
      39             :  9095,   9195,   9294,   9394,   9493,   9593,   9691,   9790,
      40             :  9889,   9987,  10085,  10182,  10280,  10377,  10474,  10570,
      41             : 10666,  10762,  10857,  10952,  11046,  11140,  11234,  11327,
      42             : 11420,  11512,  11603,  11695,  11785,  11875,  11965,  12054,
      43             : 12142,  12230,  12317,  12404,  12489,  12575,  12659,  12743,
      44             : 12826,  12909,  12991,  13072,  13152,  13232,  13311,  13389,
      45             : 13466,  13543,  13619,  13693,  13767,  13841,  13913,  13985,
      46             : 14055,  14125,  14194,  14262,  14329,  14395,  14460,  14525,
      47             : 14588,  14650,  14711,  14772,  14831,  14890,  14947,  15003,
      48             : 15059,  15113,  15166,  15219,  15270,  15320,  15369,  15417,
      49             : 15464,  15509,  15554,  15597,  15640,  15681,  15721,  15760,
      50             : 15798,  15835,  15871,  15905,  15938,  15971,  16001,  16031,
      51             : 16060,  16087,  16113,  16138,  16162,  16185,  16206,  16227,
      52             : 16246,  16263,  16280,  16295,  16309,  16322,  16334,  16345,
      53             : 16354,  16362,  16369,  16374,  16378,  16382,  16383,  16384
      54             : };
      55             : 
      56           0 : void WebRtcSpl_GetHanningWindow(int16_t *v, size_t size)
      57             : {
      58             :     size_t jj;
      59             :     int16_t *vptr1;
      60             : 
      61             :     int32_t index;
      62           0 :     int32_t factor = ((int32_t)0x40000000);
      63             : 
      64           0 :     factor = WebRtcSpl_DivW32W16(factor, (int16_t)size);
      65           0 :     if (size < 513)
      66           0 :         index = (int32_t)-0x200000;
      67             :     else
      68           0 :         index = (int32_t)-0x100000;
      69           0 :     vptr1 = v;
      70             : 
      71           0 :     for (jj = 0; jj < size; jj++)
      72             :     {
      73           0 :         index += factor;
      74           0 :         (*vptr1++) = kHanningTable[index >> 22];
      75             :     }
      76             : 
      77           0 : }