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/*
* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include "cng_helpfuns.h"
#include "signal_processing_library.h"
#include "webrtc/typedefs.h"
#include "webrtc_cng.h"
/* Values in |k| are Q15, and |a| Q12. */
void WebRtcCng_K2a16(int16_t* k, int useOrder, int16_t* a) {
int16_t any[WEBRTC_SPL_MAX_LPC_ORDER + 1];
int16_t *aptr, *aptr2, *anyptr;
const int16_t *kptr;
int m, i;
kptr = k;
*a = 4096; /* i.e., (Word16_MAX >> 3) + 1 */
*any = *a;
a[1] = (*k + 4) >> 3;
for (m = 1; m < useOrder; m++) {
kptr++;
aptr = a;
aptr++;
aptr2 = &a[m];
anyptr = any;
anyptr++;
any[m + 1] = (*kptr + 4) >> 3;
for (i = 0; i < m; i++) {
*anyptr++ = (*aptr++) +
(int16_t)((((int32_t)(*aptr2--) * (int32_t) * kptr) + 16384) >> 15);
}
aptr = a;
anyptr = any;
for (i = 0; i < (m + 2); i++) {
*aptr++ = *anyptr++;
}
}
}
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