Index: third_party/WebKit/Source/platform/audio/AudioPullFIFO.h |
diff --git a/third_party/WebKit/Source/platform/audio/AudioPullFIFO.h b/third_party/WebKit/Source/platform/audio/AudioPullFIFO.h |
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+/* |
+ * Copyright (C) 2012 Google Inc. All rights reserved. |
+ * |
+ * Redistribution and use in source and binary forms, with or without |
+ * modification, are permitted provided that the following conditions |
+ * are met: |
+ * |
+ * 1. Redistributions of source code must retain the above copyright |
+ * notice, this list of conditions and the following disclaimer. |
+ * 2. Redistributions in binary form must reproduce the above copyright |
+ * notice, this list of conditions and the following disclaimer in the |
+ * documentation and/or other materials provided with the distribution. |
+ * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of |
+ * its contributors may be used to endorse or promote products derived |
+ * from this software without specific prior written permission. |
+ * |
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY |
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED |
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE |
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY |
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES |
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; |
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND |
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
+ */ |
+ |
+#ifndef AudioPullFIFO_h |
+#define AudioPullFIFO_h |
+ |
+#include "platform/audio/AudioBus.h" |
+#include "platform/audio/AudioFIFO.h" |
+#include "platform/audio/AudioSourceProvider.h" |
+#include "wtf/Allocator.h" |
+ |
+namespace blink { |
+ |
+// A FIFO (First In First Out) buffer to handle mismatches in buffer sizes |
+// between a provider and receiver. The receiver will "pull" data from this |
+// FIFO. If data is already available in the FIFO, it is provided to the |
+// receiver. If insufficient data is available to satisfy the request, the FIFO |
+// will ask the provider for more data when necessary to fulfill a request. |
+// Contrast this with a "push" FIFO, where the sender pushes data to the FIFO |
+// which will itself push the data to the receiver when the FIFO is full. |
+class PLATFORM_EXPORT AudioPullFIFO { |
+ USING_FAST_MALLOC(AudioPullFIFO); |
+ WTF_MAKE_NONCOPYABLE(AudioPullFIFO); |
+ |
+ public: |
+ // Create a FIFO that gets data from |provider|. The FIFO will be large |
+ // enough to hold |fifoLength| frames of data of |numberOfChannels| channels. |
+ // The AudioSourceProvider will be asked to produce |providerSize| frames |
+ // when the FIFO needs more data. |
+ AudioPullFIFO(AudioSourceProvider& audioProvider, |
+ unsigned numberOfChannels, |
+ size_t fifoLength, |
+ size_t providerSize); |
+ |
+ // Read |framesToConsume| frames from the FIFO into the destination. If the |
+ // FIFO does not have enough data, we ask the |provider| to get more data to |
+ // fulfill the request. |
+ void consume(AudioBus* destination, size_t framesToConsume); |
+ |
+ private: |
+ // Fill the FIFO buffer with at least |numberOfFrames| more data. |
+ void fillBuffer(size_t numberOfFrames); |
+ |
+ // The provider of the data in our FIFO. |
+ AudioSourceProvider& m_provider; |
+ |
+ // The actual FIFO |
+ AudioFIFO m_fifo; |
+ |
+ // Number of frames of data that the provider will produce per call. |
+ unsigned m_providerSize; |
+ |
+ // Temporary workspace to hold the data from the provider. |
+ RefPtr<AudioBus> m_tempBus; |
+}; |
+ |
+} // namespace blink |
+ |
+#endif // AudioPullFIFO.h |