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/*
* Copyright (c) 2012 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 "common_audio/signal_processing/include/signal_processing_library.h"
#include "rtc_base/checks.h"
#include "rtc_base/sanitizer.h"
// TODO(Bjornv): Change the function parameter order to WebRTC code style.
// C version of WebRtcSpl_DownsampleFast() for generic platforms.
int WebRtcSpl_DownsampleFastC(const int16_t* data_in,
size_t data_in_length,
int16_t* data_out,
size_t data_out_length,
const int16_t* __restrict coefficients,
size_t coefficients_length,
int factor,
size_t delay) {
int16_t* const original_data_out = data_out;
size_t i = 0;
size_t j = 0;
int32_t out_s32 = 0;
size_t endpos = delay + factor * (data_out_length - 1) + 1;
// Return error if any of the running conditions doesn't meet.
if (data_out_length == 0 || coefficients_length == 0 ||
data_in_length < endpos) {
return -1;
}
rtc_MsanCheckInitialized(coefficients, sizeof(coefficients[0]),
coefficients_length);
for (i = delay; i < endpos; i += factor) {
out_s32 = 2048; // Round value, 0.5 in Q12.
for (j = 0; j < coefficients_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.
rtc_MsanCheckInitialized(&data_in[(ptrdiff_t)i - (ptrdiff_t)j],
sizeof(data_in[0]), 1);
// out_s32 is in Q12 domain.
out_s32 += coefficients[j] * data_in[(ptrdiff_t)i - (ptrdiff_t)j];
}
out_s32 >>= 12; // Q0.
// Saturate and store the output.
*data_out++ = WebRtcSpl_SatW32ToW16(out_s32);
}
RTC_DCHECK_EQ(original_data_out + data_out_length, data_out);
rtc_MsanCheckInitialized(original_data_out, sizeof(original_data_out[0]),
data_out_length);
return 0;
}
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