ImfIO.h 7.28 KB
Newer Older
wester committed
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252
///////////////////////////////////////////////////////////////////////////
//
// Copyright (c) 2002, Industrial Light & Magic, a division of Lucas
// Digital Ltd. LLC
//
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
// *       Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// *       Redistributions in binary form must reproduce the above
// copyright notice, this list of conditions and the following disclaimer
// in the documentation and/or other materials provided with the
// distribution.
// *       Neither the name of Industrial Light & Magic nor the names of
// its contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
///////////////////////////////////////////////////////////////////////////


#ifndef INCLUDED_IMF_IO_H
#define INCLUDED_IMF_IO_H

//-----------------------------------------------------------------------------
//
//	Low-level file input and output for OpenEXR.
//
//-----------------------------------------------------------------------------

#include <ImfInt64.h>
#include <string>

namespace Imf {

//-----------------------------------------------------------
// class IStream -- an abstract base class for input streams.
//-----------------------------------------------------------

class IStream
{
  public:

    //-----------
    // Destructor
    //-----------

    virtual ~IStream ();


    //-------------------------------------------------
    // Does this input stream support memory-mapped IO?
    //
    // Memory-mapped streams can avoid an extra copy;
    // memory-mapped read operations return a pointer
    // to an internal buffer instead of copying data
    // into a buffer supplied by the caller.
    //-------------------------------------------------

    virtual bool        isMemoryMapped () const;


    //------------------------------------------------------
    // Read from the stream:
    //
    // read(c,n) reads n bytes from the stream, and stores
    // them in array c.  If the stream contains less than n
    // bytes, or if an I/O error occurs, read(c,n) throws
    // an exception.  If read(c,n) reads the last byte from
    // the file it returns false, otherwise it returns true.
    //------------------------------------------------------

    virtual bool	read (char c[/*n*/], int n) = 0;


    //---------------------------------------------------
    // Read from a memory-mapped stream:
    //
    // readMemoryMapped(n) reads n bytes from the stream
    // and returns a pointer to the first byte.  The
    // returned pointer remains valid until the stream
    // is closed.  If there are less than n byte left to
    // read in the stream or if the stream is not memory-
    // mapped, readMemoryMapped(n) throws an exception.
    //---------------------------------------------------

    virtual char *	readMemoryMapped (int n);


    //--------------------------------------------------------
    // Get the current reading position, in bytes from the
    // beginning of the file.  If the next call to read() will
    // read the first byte in the file, tellg() returns 0.
    //--------------------------------------------------------

    virtual Int64	tellg () = 0;


    //-------------------------------------------
    // Set the current reading position.
    // After calling seekg(i), tellg() returns i.
    //-------------------------------------------

    virtual void	seekg (Int64 pos) = 0;


    //------------------------------------------------------
    // Clear error conditions after an operation has failed.
    //------------------------------------------------------

    virtual void	clear ();


    //------------------------------------------------------
    // Get the name of the file associated with this stream.
    //------------------------------------------------------

    const char *	fileName () const;

  protected:

    IStream (const char fileName[]);

  private:

    IStream (const IStream &);			// not implemented
    IStream & operator = (const IStream &);	// not implemented

    std::string		_fileName;
};


//-----------------------------------------------------------
// class OStream -- an abstract base class for output streams
//-----------------------------------------------------------

class OStream
{
  public:

    //-----------
    // Destructor
    //-----------

    virtual ~OStream ();


    //----------------------------------------------------------
    // Write to the stream:
    //
    // write(c,n) takes n bytes from array c, and stores them
    // in the stream.  If an I/O error occurs, write(c,n) throws
    // an exception.
    //----------------------------------------------------------

    virtual void	write (const char c[/*n*/], int n) = 0;


    //---------------------------------------------------------
    // Get the current writing position, in bytes from the
    // beginning of the file.  If the next call to write() will
    // start writing at the beginning of the file, tellp()
    // returns 0.
    //---------------------------------------------------------

    virtual Int64	tellp () = 0;


    //-------------------------------------------
    // Set the current writing position.
    // After calling seekp(i), tellp() returns i.
    //-------------------------------------------

    virtual void	seekp (Int64 pos) = 0;


    //------------------------------------------------------
    // Get the name of the file associated with this stream.
    //------------------------------------------------------

    const char *	fileName () const;

  protected:

    OStream (const char fileName[]);

  private:

    OStream (const OStream &);			// not implemented
    OStream & operator = (const OStream &);	// not implemented

    std::string		_fileName;
};


//-----------------------
// Helper classes for Xdr
//-----------------------

struct StreamIO
{
    static void
    writeChars (OStream &os, const char c[/*n*/], int n)
    {
    os.write (c, n);
    }

    static bool
    readChars (IStream &is, char c[/*n*/], int n)
    {
    return is.read (c, n);
    }
};


struct CharPtrIO
{
    static void
    writeChars (char *&op, const char c[/*n*/], int n)
    {
    while (n--)
        *op++ = *c++;
    }

    static bool
    readChars (const char *&ip, char c[/*n*/], int n)
    {
    while (n--)
        *c++ = *ip++;

    return true;
    }
};


} // namespace Imf

#endif