85 lines
2.8 KiB
C
85 lines
2.8 KiB
C
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/*
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* Copyright 2004 The WebRTC Project Authors. All rights reserved.
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*
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* Use of this source code is governed by a BSD-style license
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* that can be found in the LICENSE file in the root of the source
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* tree. An additional intellectual property rights grant can be found
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* in the file PATENTS. All contributing project authors may
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* be found in the AUTHORS file in the root of the source tree.
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*/
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#ifndef WEBRTC_BASE_TRANSFORMADAPTER_H__
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#define WEBRTC_BASE_TRANSFORMADAPTER_H__
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#include "webrtc/base/stream.h"
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namespace rtc {
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///////////////////////////////////////////////////////////////////////////////
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class TransformInterface {
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public:
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virtual ~TransformInterface() { }
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// Transform should convert the in_len bytes of input into the out_len-sized
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// output buffer. If flush is true, there will be no more data following
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// input.
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// After the transformation, in_len contains the number of bytes consumed, and
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// out_len contains the number of bytes ready in output.
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// Note: Transform should not return SR_BLOCK, as there is no asynchronous
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// notification available.
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virtual StreamResult Transform(const void * input, size_t * in_len,
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void * output, size_t * out_len,
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bool flush) = 0;
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};
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///////////////////////////////////////////////////////////////////////////////
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// TransformAdapter causes all data passed through to be transformed by the
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// supplied TransformInterface object, which may apply compression, encryption,
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// etc.
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class TransformAdapter : public StreamAdapterInterface {
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public:
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// Note that the transformation is unidirectional, in the direction specified
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// by the constructor. Operations in the opposite direction result in SR_EOS.
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TransformAdapter(StreamInterface * stream,
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TransformInterface * transform,
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bool direction_read);
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~TransformAdapter() override;
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StreamResult Read(void* buffer,
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size_t buffer_len,
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size_t* read,
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int* error) override;
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StreamResult Write(const void* data,
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size_t data_len,
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size_t* written,
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int* error) override;
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void Close() override;
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// Apriori, we can't tell what the transformation does to the stream length.
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bool GetAvailable(size_t* size) const override;
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bool ReserveSize(size_t size) override;
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// Transformations might not be restartable
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virtual bool Rewind();
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private:
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enum State { ST_PROCESSING, ST_FLUSHING, ST_COMPLETE, ST_ERROR };
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enum { BUFFER_SIZE = 1024 };
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TransformInterface * transform_;
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bool direction_read_;
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State state_;
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int error_;
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char buffer_[BUFFER_SIZE];
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size_t len_;
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};
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///////////////////////////////////////////////////////////////////////////////
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} // namespace rtc
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#endif // WEBRTC_BASE_TRANSFORMADAPTER_H__
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