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_AugmentedCbCorr.c
16
17******************************************************************/
18
19#include "defines.h"
20#include "constants.h"
21#include "augmented_cb_corr.h"
22
23void WebRtcIlbcfix_AugmentedCbCorr(
24    int16_t *target,   /* (i) Target vector */
25    int16_t *buffer,   /* (i) Memory buffer */
26    int16_t *interpSamples, /* (i) buffer with
27                                     interpolated samples */
28    int32_t *crossDot,  /* (o) The cross correlation between
29                                 the target and the Augmented
30                                 vector */
31    size_t low,    /* (i) Lag to start from (typically
32                             20) */
33    size_t high,   /* (i) Lag to end at (typically 39) */
34    int scale)   /* (i) Scale factor to use for
35                              the crossDot */
36{
37  size_t lagcount;
38  size_t ilow;
39  int16_t *targetPtr;
40  int32_t *crossDotPtr;
41  int16_t *iSPtr=interpSamples;
42
43  /* Calculate the correlation between the target and the
44     interpolated codebook. The correlation is calculated in
45     3 sections with the interpolated part in the middle */
46  crossDotPtr=crossDot;
47  for (lagcount=low; lagcount<=high; lagcount++) {
48
49    ilow = lagcount - 4;
50
51    /* Compute dot product for the first (lagcount-4) samples */
52    (*crossDotPtr) = WebRtcSpl_DotProductWithScale(target, buffer-lagcount, ilow, scale);
53
54    /* Compute dot product on the interpolated samples */
55    (*crossDotPtr) += WebRtcSpl_DotProductWithScale(target+ilow, iSPtr, 4, scale);
56    targetPtr = target + lagcount;
57    iSPtr += lagcount-ilow;
58
59    /* Compute dot product for the remaining samples */
60    (*crossDotPtr) += WebRtcSpl_DotProductWithScale(targetPtr, buffer-lagcount, SUBL-lagcount, scale);
61    crossDotPtr++;
62  }
63}
64