1 files changed, 108 insertions, 0 deletions
diff --git a/third_party/webrtc/src/webrtc/common_audio/signal_processing/real_fft_unittest.cc b/third_party/webrtc/src/webrtc/common_audio/signal_processing/real_fft_unittest.cc
new file mode 100644
index 00000000..9bd35cd6
--- /dev/null
+++ b/third_party/webrtc/src/webrtc/common_audio/signal_processing/real_fft_unittest.cc
@@ -0,0 +1,108 @@
+/*
+ *  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 "webrtc/common_audio/signal_processing/include/real_fft.h"
+#include "webrtc/common_audio/signal_processing/include/signal_processing_library.h"
+#include "webrtc/test/testsupport/gtest_disable.h"
+#include "webrtc/typedefs.h"
+
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace webrtc {
+namespace {
+
+// FFT order.
+const int kOrder = 5;
+// Lengths for real FFT's time and frequency bufffers.
+// For N-point FFT, the length requirements from API are N and N+2 respectively.
+const int kTimeDataLength = 1 << kOrder;
+const int kFreqDataLength = (1 << kOrder) + 2;
+// For complex FFT's time and freq buffer. The implementation requires
+// 2*N 16-bit words.
+const int kComplexFftDataLength = 2 << kOrder;
+// Reference data for time signal.
+const int16_t kRefData[kTimeDataLength] = {
+  11739, 6848, -8688, 31980, -30295, 25242, 27085, 19410,
+  -26299, 15607, -10791, 11778, -23819, 14498, -25772, 10076,
+  1173, 6848, -8688, 31980, -30295, 2522, 27085, 19410,
+  -2629, 5607, -3, 1178, -23819, 1498, -25772, 10076
+};
+
+class RealFFTTest : public ::testing::Test {
+ protected:
+   RealFFTTest() {
+     WebRtcSpl_Init();
+   }
+};
+
+TEST_F(RealFFTTest, CreateFailsOnBadInput) {
+  RealFFT* fft = WebRtcSpl_CreateRealFFT(11);
+  EXPECT_TRUE(fft == NULL);
+  fft = WebRtcSpl_CreateRealFFT(-1);
+  EXPECT_TRUE(fft == NULL);
+}
+
+TEST_F(RealFFTTest, RealAndComplexMatch) {
+  int i = 0;
+  int j = 0;
+  int16_t real_fft_time[kTimeDataLength] = {0};
+  int16_t real_fft_freq[kFreqDataLength] = {0};
+  // One common buffer for complex FFT's time and frequency data.
+  int16_t complex_fft_buff[kComplexFftDataLength] = {0};
+
+  // Prepare the inputs to forward FFT's.
+  memcpy(real_fft_time, kRefData, sizeof(kRefData));
+  for (i = 0, j = 0; i < kTimeDataLength; i += 1, j += 2) {
+    complex_fft_buff[j] = kRefData[i];
+    complex_fft_buff[j + 1] = 0;  // Insert zero's to imaginary parts.
+  };
+
+  // Create and run real forward FFT.
+  RealFFT* fft = WebRtcSpl_CreateRealFFT(kOrder);
+  EXPECT_TRUE(fft != NULL);
+  EXPECT_EQ(0, WebRtcSpl_RealForwardFFT(fft, real_fft_time, real_fft_freq));
+
+  // Run complex forward FFT.
+  WebRtcSpl_ComplexBitReverse(complex_fft_buff, kOrder);
+  EXPECT_EQ(0, WebRtcSpl_ComplexFFT(complex_fft_buff, kOrder, 1));
+
+  // Verify the results between complex and real forward FFT.
+  for (i = 0; i < kFreqDataLength; i++) {
+    EXPECT_EQ(real_fft_freq[i], complex_fft_buff[i]);
+  }
+
+  // Prepare the inputs to inverse real FFT.
+  // We use whatever data in complex_fft_buff[] since we don't care
+  // about data contents. Only kFreqDataLength 16-bit words are copied
+  // from complex_fft_buff to real_fft_freq since remaining words (2nd half)
+  // are conjugate-symmetric to the first half in theory.
+  memcpy(real_fft_freq, complex_fft_buff, sizeof(real_fft_freq));
+
+  // Run real inverse FFT.
+  int real_scale = WebRtcSpl_RealInverseFFT(fft, real_fft_freq, real_fft_time);
+  EXPECT_GE(real_scale, 0);
+
+  // Run complex inverse FFT.
+  WebRtcSpl_ComplexBitReverse(complex_fft_buff, kOrder);
+  int complex_scale = WebRtcSpl_ComplexIFFT(complex_fft_buff, kOrder, 1);
+
+  // Verify the results between complex and real inverse FFT.
+  // They are not bit-exact, since complex IFFT doesn't produce
+  // exactly conjugate-symmetric data (between first and second half).
+  EXPECT_EQ(real_scale, complex_scale);
+  for (i = 0, j = 0; i < kTimeDataLength; i += 1, j += 2) {
+    EXPECT_LE(abs(real_fft_time[i] - complex_fft_buff[j]), 1);
+  }
+
+  WebRtcSpl_FreeRealFFT(fft);
+}
+
+}  // namespace
+}  // namespace webrtc