Add LappedTransform accessors.

These are necessary for clients to validate that they conform to its API.

R=andrew@webrtc.org

Review URL: https://webrtc-codereview.appspot.com/53519005

Cr-Commit-Position: refs/heads/master@{#9327}
diff --git a/webrtc/common_audio/lapped_transform.cc b/webrtc/common_audio/lapped_transform.cc
index 3883582..0239498 100644
--- a/webrtc/common_audio/lapped_transform.cc
+++ b/webrtc/common_audio/lapped_transform.cc
@@ -24,8 +24,8 @@
                                                int num_input_channels,
                                                int num_output_channels,
                                                float* const* output) {
-  CHECK_EQ(num_input_channels, parent_->in_channels_);
-  CHECK_EQ(num_output_channels, parent_->out_channels_);
+  CHECK_EQ(num_input_channels, parent_->num_in_channels_);
+  CHECK_EQ(num_output_channels, parent_->num_out_channels_);
   CHECK_EQ(parent_->block_length_, num_frames);
 
   for (int i = 0; i < num_input_channels; ++i) {
@@ -52,25 +52,38 @@
   }
 }
 
-LappedTransform::LappedTransform(int in_channels, int out_channels,
-                                 int chunk_length, const float* window,
-                                 int block_length, int shift_amount,
+LappedTransform::LappedTransform(int num_in_channels,
+                                 int num_out_channels,
+                                 int chunk_length,
+                                 const float* window,
+                                 int block_length,
+                                 int shift_amount,
                                  Callback* callback)
     : blocker_callback_(this),
-      in_channels_(in_channels),
-      out_channels_(out_channels),
+      num_in_channels_(num_in_channels),
+      num_out_channels_(num_out_channels),
       block_length_(block_length),
       chunk_length_(chunk_length),
       block_processor_(callback),
-      blocker_(
-        chunk_length_, block_length_, in_channels_, out_channels_, window,
-        shift_amount, &blocker_callback_),
+      blocker_(chunk_length_,
+               block_length_,
+               num_in_channels_,
+               num_out_channels_,
+               window,
+               shift_amount,
+               &blocker_callback_),
       fft_(RealFourier::Create(RealFourier::FftOrder(block_length_))),
       cplx_length_(RealFourier::ComplexLength(fft_->order())),
-      real_buf_(in_channels, block_length_, RealFourier::kFftBufferAlignment),
-      cplx_pre_(in_channels, cplx_length_, RealFourier::kFftBufferAlignment),
-      cplx_post_(out_channels, cplx_length_, RealFourier::kFftBufferAlignment) {
-  CHECK(in_channels_ > 0 && out_channels_ > 0);
+      real_buf_(num_in_channels,
+                block_length_,
+                RealFourier::kFftBufferAlignment),
+      cplx_pre_(num_in_channels,
+                cplx_length_,
+                RealFourier::kFftBufferAlignment),
+      cplx_post_(num_out_channels,
+                 cplx_length_,
+                 RealFourier::kFftBufferAlignment) {
+  CHECK(num_in_channels_ > 0 && num_out_channels_ > 0);
   CHECK_GT(block_length_, 0);
   CHECK_GT(chunk_length_, 0);
   CHECK(block_processor_);
@@ -81,9 +94,8 @@
 
 void LappedTransform::ProcessChunk(const float* const* in_chunk,
                                    float* const* out_chunk) {
-  blocker_.ProcessChunk(in_chunk, chunk_length_, in_channels_, out_channels_,
-                        out_chunk);
+  blocker_.ProcessChunk(in_chunk, chunk_length_, num_in_channels_,
+                        num_out_channels_, out_chunk);
 }
 
 }  // namespace webrtc
-
diff --git a/webrtc/common_audio/lapped_transform.h b/webrtc/common_audio/lapped_transform.h
index d299bce..270644c 100644
--- a/webrtc/common_audio/lapped_transform.h
+++ b/webrtc/common_audio/lapped_transform.h
@@ -35,8 +35,8 @@
     virtual ~Callback() {}
 
     virtual void ProcessAudioBlock(const std::complex<float>* const* in_block,
-                                   int in_channels, int frames,
-                                   int out_channels,
+                                   int num_in_channels, int frames,
+                                   int num_out_channels,
                                    std::complex<float>* const* out_block) = 0;
   };
 
@@ -46,7 +46,7 @@
   // |block_length| defines the length of a block, in samples.
   // |shift_amount| is in samples. |callback| is the caller-owned audio
   // processing function called for each block of the input chunk.
-  LappedTransform(int in_channels, int out_channels, int chunk_length,
+  LappedTransform(int num_in_channels, int num_out_channels, int chunk_length,
                   const float* window, int block_length, int shift_amount,
                   Callback* callback);
   ~LappedTransform() {}
@@ -63,7 +63,24 @@
   // to ProcessChunk via the parameter in_chunk.
   //
   // Returns the same chunk_length passed to the LappedTransform constructor.
-  int get_chunk_length() const { return chunk_length_; }
+  int chunk_length() const { return chunk_length_; }
+
+  // Get the number of input channels.
+  //
+  // This is the number of arrays that must be passed to ProcessChunk via
+  // in_chunk.
+  //
+  // Returns the same num_in_channels passed to the LappedTransform constructor.
+  int num_in_channels() const { return num_in_channels_; }
+
+  // Get the number of output channels.
+  //
+  // This is the number of arrays that must be passed to ProcessChunk via
+  // out_chunk.
+  //
+  // Returns the same num_out_channels passed to the LappedTransform
+  // constructor.
+  int num_out_channels() const { return num_out_channels_; }
 
  private:
   // Internal middleware callback, given to the blocker. Transforms each block
@@ -80,8 +97,8 @@
     LappedTransform* const parent_;
   } blocker_callback_;
 
-  const int in_channels_;
-  const int out_channels_;
+  const int num_in_channels_;
+  const int num_out_channels_;
 
   const int block_length_;
   const int chunk_length_;
diff --git a/webrtc/common_audio/lapped_transform_unittest.cc b/webrtc/common_audio/lapped_transform_unittest.cc
index ac24a0d..c30651c 100644
--- a/webrtc/common_audio/lapped_transform_unittest.cc
+++ b/webrtc/common_audio/lapped_transform_unittest.cc
@@ -177,26 +177,26 @@
   ASSERT_EQ(kChunkLength / kBlockLength, call.block_num());
 }
 
-TEST(LappedTransformTest, get_chunk_length) {
+TEST(LappedTransformTest, chunk_length) {
   const int kBlockLength = 64;
   FftCheckerCallback call;
   const float window[kBlockLength] = {};
 
-  // Make sure that get_chunk_length returns the same value passed to the
+  // Make sure that chunk_length returns the same value passed to the
   // LappedTransform constructor.
   {
     const int kExpectedChunkLength = 512;
     const LappedTransform trans(1, 1, kExpectedChunkLength, window,
                                 kBlockLength, kBlockLength, &call);
 
-    EXPECT_EQ(kExpectedChunkLength, trans.get_chunk_length());
+    EXPECT_EQ(kExpectedChunkLength, trans.chunk_length());
   }
   {
     const int kExpectedChunkLength = 160;
     const LappedTransform trans(1, 1, kExpectedChunkLength, window,
                                 kBlockLength, kBlockLength, &call);
 
-    EXPECT_EQ(kExpectedChunkLength, trans.get_chunk_length());
+    EXPECT_EQ(kExpectedChunkLength, trans.chunk_length());
   }
 }