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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.
*/
/*
* This file contains the function WebRtcSpl_FilterMAFastQ12().
* The description header can be found in signal_processing_library.h
*
*/
#include "common_audio/signal_processing/include/signal_processing_library.h"
#include "rtc_base/sanitizer.h"
void WebRtcSpl_FilterMAFastQ12(const int16_t* in_ptr,
int16_t* out_ptr,
const int16_t* B,
size_t B_length,
size_t length)
{
size_t i, j;
rtc_MsanCheckInitialized(B, sizeof(B[0]), B_length);
rtc_MsanCheckInitialized(in_ptr - B_length + 1, sizeof(in_ptr[0]),
B_length + length - 1);
for (i = 0; i < length; i++)
{
int32_t o = 0;
for (j = 0; j < B_length; j++)
{
// Negative overflow is permitted here, because this is
// auto-regressive filters, and the state for each batch run is
// stored in the "negative" positions of the output vector.
o += B[j] * in_ptr[(ptrdiff_t) i - (ptrdiff_t) j];
}
// If output is higher than 32768, saturate it. Same with negative side
// 2^27 = 134217728, which corresponds to 32768 in Q12
// Saturate the output
o = WEBRTC_SPL_SAT((int32_t)134215679, o, (int32_t)-134217728);
*out_ptr++ = (int16_t)((o + (int32_t)2048) >> 12);
}
return;
}
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