Add SSE optimizations to SincResampler.

media/base/sinc_resampler.h

 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #ifndef MEDIA_BASE_SINC_RESAMPLER_H_
 #define MEDIA_BASE_SINC_RESAMPLER_H_
 
 #include "base/callback.h"
+#include "base/gtest_prod_util.h"
 #include "base/memory/scoped_ptr.h"
+#include "build/build_config.h"
 #include "media/base/media_export.h"
 
 namespace media {
 
 // SincResampler is a high-quality single-channel sample-rate converter.
 class MEDIA_EXPORT SincResampler {
  public:
   // Callback type for providing more data into the resampler.  Expects |frames|
   // of data to be rendered into |destination|; zero padded if not enough frames
   // are available to satisfy the request.
   typedef base::Callback<void(float* destination, int frames)> ReadCB;
 
   // Constructs a SincResampler with the specified |read_cb|, which is used to
   // acquire audio data for resampling.  |io_sample_rate_ratio| is the ratio of
   // input / output sample rates.
   SincResampler(double io_sample_rate_ratio, const ReadCB& read_cb);
   virtual ~SincResampler();
 
   // Resample |frames| of data from |read_cb_| into |destination|.
   void Resample(float* destination, int frames);
 
   // The maximum size in frames that guarantees Resample() will only make a
   // single call to |read_cb_| for more data.
   int ChunkSize();
 
  private:
+  FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, Convolve);
+  FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, ConvolveBenchmark);
+
   void InitializeKernel();
 
+  // Compute convolution of |k1| and |k2| over |input_ptr|, resultant sums are
+  // linearly interpolated using |kernel_interpolation_factor|.  The underlying
+  // implementation is chosen at run time based on SSE support.
+  static float Convolve(const float* input_ptr, const float* k1,
+                        const float* k2, double kernel_interpolation_factor);
+  static float Convolve_C(const float* input_ptr, const float* k1,
+                          const float* k2, double kernel_interpolation_factor);
+#if defined(ARCH_CPU_X86_FAMILY) && defined(__SSE__)

[Ami GONE FROM CHROMIUM, 2012/07/21 17:25:10]

#if unnecessary (fine to leave methods undefined as long as you don't use them).

[DaleCurtis, 2012/07/24 00:13:07]

Done.

+  static float Convolve_SSE(const float* input_ptr, const float* k1,
+                            const float* k2,
+                            double kernel_interpolation_factor);
+#endif
+
   // The ratio of input / output sample rates.
   double io_sample_rate_ratio_;
 
   // An index on the source input buffer with sub-sample precision.  It must be
   // double precision to avoid drift.
   double virtual_source_idx_;
 
   // The buffer is primed once at the very beginning of processing.
   bool buffer_primed_;
 
@@ skipping 14 matching lines @@
   float* const r1_;
   float* const r2_;
   float* const r3_;
   float* const r4_;
   float* const r5_;
 };
 
 }  // namespace media
 
 #endif  // MEDIA_BASE_SINC_RESAMPLER_H_