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/*
* Copyright (c) 2014 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 "webrtc/common_audio/fir_filter.h"
#include <assert.h>
#include <string.h>
#include "webrtc/base/scoped_ptr.h"
#include "webrtc/common_audio/fir_filter_neon.h"
#include "webrtc/common_audio/fir_filter_sse.h"
#include "webrtc/system_wrappers/include/cpu_features_wrapper.h"
namespace webrtc {
class FIRFilterC : public FIRFilter {
public:
FIRFilterC(const float* coefficients,
size_t coefficients_length);
void Filter(const float* in, size_t length, float* out) override;
private:
size_t coefficients_length_;
size_t state_length_;
rtc::scoped_ptr<float[]> coefficients_;
rtc::scoped_ptr<float[]> state_;
};
FIRFilter* FIRFilter::Create(const float* coefficients,
size_t coefficients_length,
size_t max_input_length) {
if (!coefficients || coefficients_length <= 0 || max_input_length <= 0) {
assert(false);
return NULL;
}
FIRFilter* filter = NULL;
// If we know the minimum architecture at compile time, avoid CPU detection.
#if defined(WEBRTC_ARCH_X86_FAMILY)
#if defined(__SSE2__)
filter =
new FIRFilterSSE2(coefficients, coefficients_length, max_input_length);
#else
// x86 CPU detection required.
if (WebRtc_GetCPUInfo(kSSE2)) {
filter =
new FIRFilterSSE2(coefficients, coefficients_length, max_input_length);
} else {
filter = new FIRFilterC(coefficients, coefficients_length);
}
#endif
#elif defined(WEBRTC_HAS_NEON)
filter =
new FIRFilterNEON(coefficients, coefficients_length, max_input_length);
#elif defined(WEBRTC_DETECT_NEON)
if (WebRtc_GetCPUFeaturesARM() & kCPUFeatureNEON) {
filter =
new FIRFilterNEON(coefficients, coefficients_length, max_input_length);
} else {
filter = new FIRFilterC(coefficients, coefficients_length);
}
#else
filter = new FIRFilterC(coefficients, coefficients_length);
#endif
return filter;
}
FIRFilterC::FIRFilterC(const float* coefficients, size_t coefficients_length)
: coefficients_length_(coefficients_length),
state_length_(coefficients_length - 1),
coefficients_(new float[coefficients_length_]),
state_(new float[state_length_]) {
for (size_t i = 0; i < coefficients_length_; ++i) {
coefficients_[i] = coefficients[coefficients_length_ - i - 1];
}
memset(state_.get(), 0, state_length_ * sizeof(state_[0]));
}
void FIRFilterC::Filter(const float* in, size_t length, float* out) {
assert(length > 0);
// Convolves the input signal |in| with the filter kernel |coefficients_|
// taking into account the previous state.
for (size_t i = 0; i < length; ++i) {
out[i] = 0.f;
size_t j;
for (j = 0; state_length_ > i && j < state_length_ - i; ++j) {
out[i] += state_[i + j] * coefficients_[j];
}
for (; j < coefficients_length_; ++j) {
out[i] += in[j + i - state_length_] * coefficients_[j];
}
}
// Update current state.
if (length >= state_length_) {
memcpy(
state_.get(), &in[length - state_length_], state_length_ * sizeof(*in));
} else {
memmove(state_.get(),
&state_[length],
(state_length_ - length) * sizeof(state_[0]));
memcpy(&state_[state_length_ - length], in, length * sizeof(*in));
}
}
} // namespace webrtc
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