1/* 2 * libjingle 3 * Copyright 2004--2005, Google Inc. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright notice, 9 * this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright notice, 11 * this list of conditions and the following disclaimer in the documentation 12 * and/or other materials provided with the distribution. 13 * 3. The name of the author may not be used to endorse or promote products 14 * derived from this software without specific prior written permission. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR IMPLIED 17 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF 18 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO 19 * EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 20 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 21 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; 22 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, 23 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR 24 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF 25 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 26 */ 27 28#ifndef TALK_BASE_TRANSFORMADAPTER_H__ 29#define TALK_BASE_TRANSFORMADAPTER_H__ 30 31#include "talk/base/stream.h" 32 33namespace talk_base { 34/////////////////////////////////////////////////////////////////////////////// 35 36class TransformInterface { 37public: 38 virtual ~TransformInterface() { } 39 40 // Transform should convert the in_len bytes of input into the out_len-sized 41 // output buffer. If flush is true, there will be no more data following 42 // input. 43 // After the transformation, in_len contains the number of bytes consumed, and 44 // out_len contains the number of bytes ready in output. 45 // Note: Transform should not return SR_BLOCK, as there is no asynchronous 46 // notification available. 47 virtual StreamResult Transform(const void * input, size_t * in_len, 48 void * output, size_t * out_len, 49 bool flush) = 0; 50}; 51 52/////////////////////////////////////////////////////////////////////////////// 53 54// TransformAdapter causes all data passed through to be transformed by the 55// supplied TransformInterface object, which may apply compression, encryption, 56// etc. 57 58class TransformAdapter : public StreamAdapterInterface { 59public: 60 // Note that the transformation is unidirectional, in the direction specified 61 // by the constructor. Operations in the opposite direction result in SR_EOS. 62 TransformAdapter(StreamInterface * stream, 63 TransformInterface * transform, 64 bool direction_read); 65 virtual ~TransformAdapter(); 66 67 virtual StreamResult Read(void * buffer, size_t buffer_len, 68 size_t * read, int * error); 69 virtual StreamResult Write(const void * data, size_t data_len, 70 size_t * written, int * error); 71 virtual void Close(); 72 73 // Apriori, we can't tell what the transformation does to the stream length. 74 virtual bool GetAvailable(size_t* size) const { return false; } 75 virtual bool ReserveSize(size_t size) { return true; } 76 77 // Transformations might not be restartable 78 virtual bool Rewind() { return false; } 79 80private: 81 enum State { ST_PROCESSING, ST_FLUSHING, ST_COMPLETE, ST_ERROR }; 82 enum { BUFFER_SIZE = 1024 }; 83 84 TransformInterface * transform_; 85 bool direction_read_; 86 State state_; 87 int error_; 88 89 char buffer_[BUFFER_SIZE]; 90 size_t len_; 91}; 92 93/////////////////////////////////////////////////////////////////////////////// 94 95} // namespace talk_base 96 97#endif // TALK_BASE_TRANSFORMADAPTER_H__ 98