OpenMAX for video decoder

Base class of using a OMX component for video decoding.
This class defines the specific behavior of using an OMX
component for video decoding. It tries not to be hardware
specific as much as possible.

Review URL: http://codereview.chromium.org/372037

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@31770 0039d316-1c4b-4281-b951-d872f2087c98

media/omx/input_buffer.cc

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+// Copyright (c) 2009 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.
+
+#include <algorithm>
+
+#include "base/logging.h"
+#include "media/omx/input_buffer.h"
+
+namespace media {
+
+InputBuffer::InputBuffer()
+    : data_(NULL),
+      size_(0),
+      used_(0) {
+}
+
+InputBuffer::InputBuffer(uint8* data, int size)
+    : data_(data),
+      size_(size),
+      used_(0) {
+  DCHECK_GE(size, 0);
+}
+
+InputBuffer::~InputBuffer() {
+  delete [] data_;
+}
+
+int InputBuffer::Read(uint8* output_data, int output_size) {
+  int copy = std::min(output_size, size_ - used_);
+  memcpy(output_data, data_ + used_, copy);
+  used_ += copy;
+  return copy;
+}
+
+bool InputBuffer::Used() {
+  return used_ == size_;
+}
+
+bool InputBuffer::Eos() {
+  return data_ == NULL || size_ == 0;
+}
+
+}  // namespace media

media/omx/input_buffer.h

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+// Copyright (c) 2009 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.
+
+// Defines the input buffer object for the video decoder. This provides
+// the interface needed by the video decoder to read input data.
+//
+// This object is implemened using system memory.
+
+#include "base/basictypes.h"
+
+namespace media {
+
+class InputBuffer {
+ public:
+  // Creates an empty input buffer.
+  InputBuffer();
+
+  // Creates an input buffer given |data| and |size|.
+  // After construction, this object will be given the ownership of
+  // |data| and is responsible for deleting it.
+  InputBuffer(uint8* data, int size);
+  virtual ~InputBuffer();
+
+  // Read from the this buffer into |data| with the maximum |size| bytes.
+  // Returns number of bytes read. If a read is successful, the number
+  // of used bytes will advances accordingly.
+  // Returns a negative number on error.
+  virtual int Read(uint8* data, int size);
+
+  // Returns true if this buffer is used.
+  virtual bool Used();
+
+  // Returns true if this is an end-of-stream buffer.
+  virtual bool Eos();
+
+ private:
+  uint8* data_;
+  int size_;
+  int used_;
+};
+
+}  // namespace media