imfxdr.h

对gif

///////////////////////////////////////////////////////////////////////////
//
// 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_XDR_H
#define INCLUDED_IMF_XDR_H

//----------------------------------------------------------------------------
//
//	Xdr -- routines to convert data between the machine's native
//	format and a machine-independent external data representation:
//
//	    write<R> (T &o, S v);	converts a value, v, of type S
//					into a machine-independent
//					representation and stores the
//					result in an output buffer, o.
//
//	    read<R> (T &i, S &v);	reads the machine-independent
//					representation of a value of type
//					S from input buffer i, converts
//					the value into the machine's native
//					representation, and stores the result
//					in v.
//
//	    size<S>();			returns the size, in bytes, of the
//					machine-independent representation
//					of an object of type S.
//					
//	The write() and read() routines are templates; data can be written
//	to and read from any output or input buffer type T for which a helper
//	class, R, exits.  Class R must define a method to store a char array
//	in a T, and a method to read a char array from a T:
//
//	    struct R
//	    {
//	        static void
//	        writeChars (T &o, const char c[/*n*/], int n)
//	        {
//	            ... // Write c[0], c[1] ... c[n-1] to output buffer o.
//	        }
//
//	        static void
//	        readChars (T &i, char c[/*n*/], int n)
//	        {
//	            ... // Read n characters from input buffer i
//		        // and copy them to c[0], c[1] ... c[n-1].
//	        }
//	    };
//
//	Example - writing to and reading from iostreams:
//
//	    struct CharStreamIO
//	    {
//	        static void
//	        writeChars (ostream &os, const char c[], int n)
//	        {
//	            os.write (c, n);
//	        }
//
//	        static void
//	        readChars (istream &is, char c[], int n)
//	        {
//	            is.read (c, n);
//	        }
//	    };
//
//          ...
//
//	    Xdr::write<CharStreamIO> (os, 3);
//	    Xdr::write<CharStreamIO> (os, 5.0);
//
//----------------------------------------------------------------------------

#include <ImfInt64.h>
#include "IexMathExc.h"
#include "half.h"
#include <limits.h>

namespace Imf {
namespace Xdr {


//-------------------------------
// Write data to an output stream
//-------------------------------

template <class S, class T>
void
write (T &out, bool v);

template <class S, class T>
void
write (T &out, char v);

template <class S, class T>
void
write (T &out, signed char v);

template <class S, class T>
void
write (T &out, unsigned char v);

template <class S, class T>
void
write (T &out, signed short v);

template <class S, class T>
void
write (T &out, unsigned short v);

template <class S, class T>
void
write (T &out, signed int v);

template <class S, class T>
void
write (T &out, unsigned int v);

template <class S, class T>
void
write (T &out, signed long v);

template <class S, class T>
void
write (T &out, unsigned long v);

#if ULONG_MAX != 18446744073709551615LU

    template <class S, class T>
    void
    write (T &out, Int64 v);

#endif

template <class S, class T>
void
write (T &out, float v);

template <class S, class T>
void
write (T &out, double v);

template <class S, class T>
void
write (T &out, half v);

template <class S, class T>
void
write (T &out, const char v[/*n*/], int n);	// fixed-size char array

template <class S, class T>
void
write (T &out, const char v[]);			// zero-terminated string


//-----------------------------------------
// Append padding bytes to an output stream
//-----------------------------------------

template <class S, class T>
void
pad (T &out, int n);				// write n padding bytes



//-------------------------------
// Read data from an input stream
//-------------------------------

template <class S, class T>
void
read (T &in, bool &v);

template <class S, class T>
void
read (T &in, char &v);

template <class S, class T>
void
read (T &in, signed char &v);

template <class S, class T>
void
read (T &in, unsigned char &v);

template <class S, class T>
void
read (T &in, signed short &v);

template <class S, class T>
void
read (T &in, unsigned short &v);

template <class S, class T>
void
read (T &in, signed int &v);

template <class S, class T>
void
read (T &in, unsigned int &v);

template <class S, class T>
void
read (T &in, signed long &v);

template <class S, class T>
void
read (T &in, unsigned long &v);

#if ULONG_MAX != 18446744073709551615LU

    template <class S, class T>
    void
    read (T &in, Int64 &v);

#endif

template <class S, class T>
void
read (T &in, float &v);

template <class S, class T>
void
read (T &in, double &v);

template <class S, class T>
void
read (T &in, half &v);

template <class S, class T>
void
read (T &in, char v[/*n*/], int n);		// fixed-size char array

template <class S, class T>
void
read (T &in, int n, char v[/*n*/]);		// zero-terminated string


//-------------------------------------------
// Skip over padding bytes in an input stream
//-------------------------------------------

template <class S, class T>
void
skip (T &in, int n);				// skip n padding bytes



//--------------------------------------
// Size of the machine-independent
// representation of an object of type S
//--------------------------------------

template <class S>
int
size ();


//---------------
// Implementation
//---------------

template <class S, class T>
inline void
writeSignedChars (T &out, const signed char c[], int n)
{
    S::writeChars (out, (const char *) c, n);
}


template <class S, class T>
inline void
writeUnsignedChars (T &out, const unsigned char c[], int n)
{
    S::writeChars (out, (const char *) c, n);
}


template <class S, class T>
inline void
readSignedChars (T &in, signed char c[], int n)
{
    S::readChars (in, (char *) c, n);
}


template <class S, class T>
inline void
readUnsignedChars (T &in, unsigned char c[], int n)
{
    S::readChars (in, (char *) c, n);
}


template <class S, class T>
inline void
write (T &out, bool v)
{
    char c = !!v;
    S::writeChars (out, &c, 1);
}


template <class S, class T>
inline void
write (T &out, char v)
{
    S::writeChars (out, &v, 1);
}


template <class S, class T>
inline void
write (T &out, signed char v)
{
    writeSignedChars<S> (out, &v, 1);
}


template <class S, class T>
inline void
write (T &out, unsigned char v)
{
    writeUnsignedChars<S> (out, &v, 1);
}


template <class S, class T>
void
write (T &out, signed short v)
{
    signed char b[2];

    b[0] =  (signed char) (v);
    b[1] =  (signed char) (v >> 8);

    writeSignedChars<S> (out, b, 2);
}


template <class S, class T>
void
write (T &out, unsigned short v)
{
    unsigned char b[2];

    b[0] =  (unsigned char) (v);
    b[1] =  (unsigned char) (v >> 8);

    writeUnsignedChars<S> (out, b, 2);
}


template <class S, class T>
void
write (T &out, signed int v)
{
    signed char b[4];

    b[0] =  (signed char) (v);
    b[1] =  (signed char) (v >> 8);
    b[2] =  (signed char) (v >> 16);
    b[3] =  (signed char) (v >> 24);

    writeSignedChars<S> (out, b, 4);
}


template <class S, class T>
void
write (T &out, unsigned int v)
{
    unsigned char b[4];

    b[0] =  (unsigned char) (v);
    b[1] =  (unsigned char) (v >> 8);
    b[2] =  (unsigned char) (v >> 16);
    b[3] =  (unsigned char) (v >> 24);

    writeUnsignedChars<S> (out, b, 4);
}


template <class S, class T>
void
write (T &out, signed long v)
{
    signed char b[8];

    b[0] = (signed char) (v);
    b[1] = (signed char) (v >> 8);
    b[2] = (signed char) (v >> 16);
    b[3] = (signed char) (v >> 24);

    #if LONG_MAX == 2147483647

	if (v >= 0)
	{
	    b[4] = 0;
	    b[5] = 0;
	    b[6] = 0;
	    b[7] = 0;
	}
	else
	{
	    b[4] = ~0;
	    b[5] = ~0;
	    b[6] = ~0;
	    b[7] = ~0;
	}

    #elif LONG_MAX == 9223372036854775807L

	b[4] = (signed char) (v >> 32);
	b[5] = (signed char) (v >> 40);
	b[6] = (signed char) (v >> 48);
	b[7] = (signed char) (v >> 56);

    #else
	
	#error write<T> (T &out, signed long v) not implemented

    #endif

    writeSignedChars<S> (out, b, 8);
}