1/**************************************************************************** 2** libebml : parse EBML files, see http://embl.sourceforge.net/ 3** 4** <file/class description> 5** 6** Copyright (C) 2002-2004 Ingo Ralf Blum. All rights reserved. 7** 8** This library is free software; you can redistribute it and/or 9** modify it under the terms of the GNU Lesser General Public 10** License as published by the Free Software Foundation; either 11** version 2.1 of the License, or (at your option) any later version. 12** 13** This library is distributed in the hope that it will be useful, 14** but WITHOUT ANY WARRANTY; without even the implied warranty of 15** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 16** Lesser General Public License for more details. 17** 18** You should have received a copy of the GNU Lesser General Public 19** License along with this library; if not, write to the Free Software 20** Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA 21** 22** See http://www.matroska.org/license/lgpl/ for LGPL licensing information. 23** 24** Contact license@matroska.org if any conditions of this licensing are 25** not clear to you. 26** 27**********************************************************************/ 28 29/*! 30 \file 31 \version \$Id: IOCallback.h 639 2004-07-09 20:59:14Z mosu $ 32*/ 33#ifndef MATROSKA_IOCALLBACK_H 34#define MATROSKA_IOCALLBACK_H 35 36#include "EbmlTypes.h" 37 38#include <exception> 39#include <cstdio> 40// #include <iostream> 41 42 43START_LIBEBML_NAMESPACE 44 45enum seek_mode 46{ 47 seek_beginning=SEEK_SET 48 ,seek_end=SEEK_END 49 ,seek_current=SEEK_CUR 50}; 51 52class EBML_DLL_API IOCallback 53{ 54public: 55 virtual ~IOCallback(){} 56 57 // The read callback works like most other read functions. You specify the 58 // file, the buffer and the size and the function returns the bytes read. 59 // If an error occurs or the file pointer points to the end of the file 0 is returned. 60 // Users are encouraged to throw a descriptive exception, when an error occurs. 61 virtual uint32 read(void*Buffer,size_t Size)=0; 62 63 // Seek to the specified position. The mode can have either SEEK_SET, SEEK_CUR 64 // or SEEK_END. The callback should return true(1) if the seek operation succeeded 65 // or false (0), when the seek fails. 66 virtual void setFilePointer(int64 Offset,seek_mode Mode=seek_beginning)=0; 67 68 // This callback just works like its read pendant. It returns the number of bytes written. 69 virtual size_t write(const void*Buffer,size_t Size)=0; 70 71 // Although the position is always positive, the return value of this callback is signed to 72 // easily allow negative values for returning errors. When an error occurs, the implementor 73 // should return -1 and the file pointer otherwise. 74 // 75 // If an error occurs, an exception should be thrown. 76 virtual uint64 getFilePointer()=0; 77 78 // The close callback flushes the file buffers to disk and closes the file. When using the stdio 79 // library, this is equivalent to calling fclose. When the close is not successful, an exception 80 // should be thrown. 81 virtual void close()=0; 82 83 84 // The readFully is made virtual to allow derived classes to use another 85 // implementation for this method, which e.g. does not read any data 86 // unlike this does 87 void readFully(void*Buffer,size_t Size); 88 89 template<class STRUCT> void readStruct(STRUCT&Struct){readFully(&Struct,sizeof(Struct));} 90 91 void writeFully(const void*Buffer,size_t Size); 92 93 template<class STRUCT> void writeStruct(const STRUCT&Struct){writeFully(&Struct,sizeof(Struct));} 94}; 95 96/* cygwin incompatible 97template<class TRAITS> std::basic_ostream<char,TRAITS>&operator<<(std::basic_ostream<char,TRAITS>&Stream,seek_mode Mode) 98{ 99 switch(Mode) 100 { 101#define x(y) case seek_##y: Stream<<"seek_" #y; break 102 x(beginning); 103 x(current); 104 x(end); 105#undef x 106 default: 107 assert(false); 108 } 109 110 return Stream; 111} 112*/ 113 114END_LIBEBML_NAMESPACE 115 116#endif // MATROSKA_IOCALLBACK_H 117