1 files changed, 58 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/audio_processing/aec3/aec3_common.cc b/third_party/libwebrtc/modules/audio_processing/aec3/aec3_common.cc
new file mode 100644
index 0000000000..3ba10d5baf
--- /dev/null
+++ b/third_party/libwebrtc/modules/audio_processing/aec3/aec3_common.cc
@@ -0,0 +1,58 @@
+/*
+ *  Copyright (c) 2017 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 "modules/audio_processing/aec3/aec3_common.h"
+
+#include <stdint.h>
+
+#include "rtc_base/checks.h"
+#include "rtc_base/system/arch.h"
+#include "system_wrappers/include/cpu_features_wrapper.h"
+
+namespace webrtc {
+
+Aec3Optimization DetectOptimization() {
+#if defined(WEBRTC_ARCH_X86_FAMILY)
+  if (GetCPUInfo(kAVX2) != 0) {
+    return Aec3Optimization::kAvx2;
+  } else if (GetCPUInfo(kSSE2) != 0) {
+    return Aec3Optimization::kSse2;
+  }
+#endif
+
+#if defined(WEBRTC_HAS_NEON)
+  return Aec3Optimization::kNeon;
+#else
+  return Aec3Optimization::kNone;
+#endif
+}
+
+float FastApproxLog2f(const float in) {
+  RTC_DCHECK_GT(in, .0f);
+  // Read and interpret float as uint32_t and then cast to float.
+  // This is done to extract the exponent (bits 30 - 23).
+  // "Right shift" of the exponent is then performed by multiplying
+  // with the constant (1/2^23). Finally, we subtract a constant to
+  // remove the bias (https://en.wikipedia.org/wiki/Exponent_bias).
+  union {
+    float dummy;
+    uint32_t a;
+  } x = {in};
+  float out = x.a;
+  out *= 1.1920929e-7f;  // 1/2^23
+  out -= 126.942695f;    // Remove bias.
+  return out;
+}
+
+float Log2TodB(const float in_log2) {
+  return 3.0102999566398121 * in_log2;
+}
+
+}  // namespace webrtc