///////////////////////////////////////////////////////////////////////////

//

// 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 "ImfNamespace.h"

#include "ImfExport.h"

#include <string>

OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_ENTER

//-----------------------------------------------------------

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

//-----------------------------------------------------------

class IStream

{

  public:

    //-----------

    // Destructor

    //-----------

    IMF_EXPORT

    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.

    //-------------------------------------------------

    IMF_EXPORT

    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.  

    //---------------------------------------------------

    IMF_EXPORT

    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.

    //------------------------------------------------------

    IMF_EXPORT

    virtual void  clear ();

    //------------------------------------------------------

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

    //------------------------------------------------------

    IMF_EXPORT

    const char *  fileName () const;

  protected:

    IMF_EXPORT

    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

    //-----------

    IMF_EXPORT

    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.

    //------------------------------------------------------

    IMF_EXPORT

    const char *  fileName () const;

  protected:

    IMF_EXPORT

    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;

    }

};

OPENEXR_IMF_INTERNAL_NAMESPACE_HEADER_EXIT

#endif