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 iLBC Speech Coder ANSI-C Source Code
14
15 WebRtcIlbcfix_MyCorr.c
16
17******************************************************************/
18
19#include "defines.h"
20
21/*----------------------------------------------------------------*
22 * compute cross correlation between sequences
23 *---------------------------------------------------------------*/
24
25void WebRtcIlbcfix_MyCorr(
26    int32_t *corr,  /* (o) correlation of seq1 and seq2 */
27    int16_t *seq1,  /* (i) first sequence */
28    int16_t dim1,  /* (i) dimension first seq1 */
29    const int16_t *seq2, /* (i) second sequence */
30    int16_t dim2   /* (i) dimension seq2 */
31                          ){
32  int16_t max, scale, loops;
33
34  /* Calculate correlation between the two sequences. Scale the
35     result of the multiplcication to maximum 26 bits in order
36     to avoid overflow */
37  max=WebRtcSpl_MaxAbsValueW16(seq1, dim1);
38  scale=WebRtcSpl_GetSizeInBits(max);
39
40  scale = (int16_t)(WEBRTC_SPL_MUL_16_16(2,scale)-26);
41  if (scale<0) {
42    scale=0;
43  }
44
45  loops=dim1-dim2+1;
46
47  /* Calculate the cross correlations */
48  WebRtcSpl_CrossCorrelation(corr, (int16_t*)seq2, seq1, dim2, loops, scale, 1);
49
50  return;
51}
52