1 /////////////////////////////////////////////////////////////////////////// 2 // 3 // Copyright (c) 2002, Industrial Light & Magic, a division of Lucas 4 // Digital Ltd. LLC 5 // 6 // All rights reserved. 7 // 8 // Redistribution and use in source and binary forms, with or without 9 // modification, are permitted provided that the following conditions are 10 // met: 11 // * Redistributions of source code must retain the above copyright 12 // notice, this list of conditions and the following disclaimer. 13 // * Redistributions in binary form must reproduce the above 14 // copyright notice, this list of conditions and the following disclaimer 15 // in the documentation and/or other materials provided with the 16 // distribution. 17 // * Neither the name of Industrial Light & Magic nor the names of 18 // its contributors may be used to endorse or promote products derived 19 // from this software without specific prior written permission. 20 // 21 // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 24 // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT 25 // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, 26 // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT 27 // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 28 // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 29 // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 30 // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE 31 // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 32 // 33 /////////////////////////////////////////////////////////////////////////// 34 35 36 #ifndef INCLUDED_IMF_IO_H 37 #define INCLUDED_IMF_IO_H 38 39 //----------------------------------------------------------------------------- 40 // 41 // Low-level file input and output for OpenEXR. 42 // 43 //----------------------------------------------------------------------------- 44 45 #include <ImfInt64.h> 46 #include <string> 47 48 namespace Imf { 49 50 //----------------------------------------------------------- 51 // class IStream -- an abstract base class for input streams. 52 //----------------------------------------------------------- 53 54 class IStream 55 { 56 public: 57 58 //----------- 59 // Destructor 60 //----------- 61 62 virtual ~IStream (); 63 64 65 //------------------------------------------------- 66 // Does this input stream support memory-mapped IO? 67 // 68 // Memory-mapped streams can avoid an extra copy; 69 // memory-mapped read operations return a pointer 70 // to an internal buffer instead of copying data 71 // into a buffer supplied by the caller. 72 //------------------------------------------------- 73 74 virtual bool isMemoryMapped () const; 75 76 77 //------------------------------------------------------ 78 // Read from the stream: 79 // 80 // read(c,n) reads n bytes from the stream, and stores 81 // them in array c. If the stream contains less than n 82 // bytes, or if an I/O error occurs, read(c,n) throws 83 // an exception. If read(c,n) reads the last byte from 84 // the file it returns false, otherwise it returns true. 85 //------------------------------------------------------ 86 87 virtual bool read (char c[/*n*/], int n) = 0; 88 89 90 //--------------------------------------------------- 91 // Read from a memory-mapped stream: 92 // 93 // readMemoryMapped(n) reads n bytes from the stream 94 // and returns a pointer to the first byte. The 95 // returned pointer remains valid until the stream 96 // is closed. If there are less than n byte left to 97 // read in the stream or if the stream is not memory- 98 // mapped, readMemoryMapped(n) throws an exception. 99 //--------------------------------------------------- 100 101 virtual char * readMemoryMapped (int n); 102 103 104 //-------------------------------------------------------- 105 // Get the current reading position, in bytes from the 106 // beginning of the file. If the next call to read() will 107 // read the first byte in the file, tellg() returns 0. 108 //-------------------------------------------------------- 109 110 virtual Int64 tellg () = 0; 111 112 113 //------------------------------------------- 114 // Set the current reading position. 115 // After calling seekg(i), tellg() returns i. 116 //------------------------------------------- 117 118 virtual void seekg (Int64 pos) = 0; 119 120 121 //------------------------------------------------------ 122 // Clear error conditions after an operation has failed. 123 //------------------------------------------------------ 124 125 virtual void clear (); 126 127 128 //------------------------------------------------------ 129 // Get the name of the file associated with this stream. 130 //------------------------------------------------------ 131 132 const char * fileName () const; 133 134 protected: 135 136 IStream (const char fileName[]); 137 138 private: 139 140 IStream (const IStream &); // not implemented 141 IStream & operator = (const IStream &); // not implemented 142 143 std::string _fileName; 144 }; 145 146 147 //----------------------------------------------------------- 148 // class OStream -- an abstract base class for output streams 149 //----------------------------------------------------------- 150 151 class OStream 152 { 153 public: 154 155 //----------- 156 // Destructor 157 //----------- 158 159 virtual ~OStream (); 160 161 162 //---------------------------------------------------------- 163 // Write to the stream: 164 // 165 // write(c,n) takes n bytes from array c, and stores them 166 // in the stream. If an I/O error occurs, write(c,n) throws 167 // an exception. 168 //---------------------------------------------------------- 169 170 virtual void write (const char c[/*n*/], int n) = 0; 171 172 173 //--------------------------------------------------------- 174 // Get the current writing position, in bytes from the 175 // beginning of the file. If the next call to write() will 176 // start writing at the beginning of the file, tellp() 177 // returns 0. 178 //--------------------------------------------------------- 179 180 virtual Int64 tellp () = 0; 181 182 183 //------------------------------------------- 184 // Set the current writing position. 185 // After calling seekp(i), tellp() returns i. 186 //------------------------------------------- 187 188 virtual void seekp (Int64 pos) = 0; 189 190 191 //------------------------------------------------------ 192 // Get the name of the file associated with this stream. 193 //------------------------------------------------------ 194 195 const char * fileName () const; 196 197 protected: 198 199 OStream (const char fileName[]); 200 201 private: 202 203 OStream (const OStream &); // not implemented 204 OStream & operator = (const OStream &); // not implemented 205 206 std::string _fileName; 207 }; 208 209 210 //----------------------- 211 // Helper classes for Xdr 212 //----------------------- 213 214 struct StreamIO 215 { 216 static void 217 writeChars (OStream &os, const char c[/*n*/], int n) 218 { 219 os.write (c, n); 220 } 221 222 static bool 223 readChars (IStream &is, char c[/*n*/], int n) 224 { 225 return is.read (c, n); 226 } 227 }; 228 229 230 struct CharPtrIO 231 { 232 static void 233 writeChars (char *&op, const char c[/*n*/], int n) 234 { 235 while (n--) 236 *op++ = *c++; 237 } 238 239 static bool 240 readChars (const char *&ip, char c[/*n*/], int n) 241 { 242 while (n--) 243 *c++ = *ip++; 244 245 return true; 246 } 247 }; 248 249 250 } // namespace Imf 251 252 #endif 253
