14b43beb7c
TBR=niklas.enbom@webrtc.org Review URL: https://webrtc-codereview.appspot.com/915006 git-svn-id: http://webrtc.googlecode.com/svn/trunk@2963 4adac7df-926f-26a2-2b94-8c16560cd09d
51 lines
1.3 KiB
C
51 lines
1.3 KiB
C
/*
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* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#include "cng_helpfuns.h"
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#include "signal_processing_library.h"
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#include "typedefs.h"
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#include "webrtc_cng.h"
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/* Values in |k| are Q15, and |a| Q12. */
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void WebRtcCng_K2a16(int16_t* k, int useOrder, int16_t* a) {
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int16_t any[WEBRTC_SPL_MAX_LPC_ORDER + 1];
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int16_t *aptr, *aptr2, *anyptr;
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const int16_t *kptr;
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int m, i;
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kptr = k;
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*a = 4096; /* i.e., (Word16_MAX >> 3) + 1 */
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*any = *a;
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a[1] = (*k + 4) >> 3;
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for (m = 1; m < useOrder; m++) {
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kptr++;
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aptr = a;
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aptr++;
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aptr2 = &a[m];
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anyptr = any;
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anyptr++;
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any[m + 1] = (*kptr + 4) >> 3;
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for (i = 0; i < m; i++) {
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*anyptr++ = (*aptr++) +
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(WebRtc_Word16)(
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(((WebRtc_Word32)(*aptr2--) * (WebRtc_Word32) * kptr) + 16384)
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>> 15);
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}
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aptr = a;
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anyptr = any;
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for (i = 0; i < (m + 2); i++) {
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*aptr++ = *anyptr++;
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}
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}
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}
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