cvr::endianness< E > Class Template Reference

Endianness. More...

#include <cvrEndianness.h>

List of all members.

Public Member Functions
	endianness ()
	~endianness ()
Static Public Member Functions
static bool	read (std::istream &in, byte &data)
static bool	read (std::istream &in, ubyte &data)
static bool	read (std::istream &in, int16 &data)
static bool	read (std::istream &in, uint16 &data)
static bool	read (std::istream &in, int32 &data)
static bool	read (std::istream &in, uint32 &data)
static bool	write (std::ostream &out, const byte &data)
static bool	write (std::ostream &out, const ubyte &data)
static bool	write (std::ostream &out, const int16 &data)
static bool	write (std::ostream &out, const uint16 &data)
static bool	write (std::ostream &out, const int32 &data)
static bool	write (std::ostream &out, const uint32 &data)

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Detailed Description

template<eEndiannessType E>
class cvr::endianness< E >

Endianness.

This template class is used to read from or write data to a file that was created with a known endianness. For example, Windows BMP image files have a header with some integers written with little endianness.

To be more specific, the problem this class tries to solve is the following:

Let us assume we have a binary file (and not an ASCII file) with following byte stream:

0x01 0x02 0x03 0x04 ...

and we use following code to read an 32 bit integer (i.e. 4 bytes long):

   cvr::uint32 integer;             // hold the values been readed
   std::istream in("theFile.dat");  // the input stream

  ...
  in.read(&integer,4);             // reads 4 bytes on "integer"

With a little endian system (for example Intel Pentium), the contents of integer will be 0x04030201.

With a big endian system (for example Motorola/IBM PowerPC), the contents of integer will be 0x01020304.

We therefore need a class, which allow us to load data from a file with the correct endiannes!

The detection of the system endianness will be done at configuration time of the library.:

• For Windows systems there is no problem if they run on Intel Processors (always little-endian). If you need to change this (for example you have an Alpha processor), change the endianness on the file cvrWinConfig.h, ensuring that the symbol WORDS_BIGENDIAN is defined as 1.

• For Unix systems the processor and endianness are determined automatically by the configure script. If the file config.h exists, everything should be ok!! In case you really need to change the detected configuration, in config.h the symbol WORDS_BIGENDIAN is defined only in big endian systems.

Template behaviour.

The class cvr::endianness is a template class of an enumerate that can be LittleEndian or BigEndian, defined in the lti namespace.

cvr::endianness<cvr::LittleEndian> cvr::endianness<cvr::BigEndian>

You can check for the endianness used as default by your system with systemEndianness().

Please note that all methods are static, so that you don't need an instance of the class to use them.

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Constructor & Destructor Documentation

template<eEndiannessType E>

cvr::endianness< E >::endianness

(

)

Default constructor.

template<eEndiannessType E>

cvr::endianness< E >::~endianness

(

)

Destructor.

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Member Function Documentation

template<eEndiannessType E>

static bool cvr::endianness< E >::read	(	std::istream &	in,
		uint32 &	data
	)			[static]

Read a uint32.

Parameters:

	in	input stream
	data	variable where the data should be stored

Returns:

a reference to the variable with the readed data

template<eEndiannessType E>

static bool cvr::endianness< E >::read	(	std::istream &	in,
		int32 &	data
	)			[static]

Read a int32.

Parameters:

	in	input stream
	data	variable where the data should be stored

Returns:

a reference to the variable with the readed data

template<eEndiannessType E>

static bool cvr::endianness< E >::read	(	std::istream &	in,
		uint16 &	data
	)			[static]

Read a uint16 (2 bytes).

Parameters:

	in	input stream
	data	variable where the data should be stored

Returns:

a reference to the variable with the readed data

template<eEndiannessType E>

static bool cvr::endianness< E >::read	(	std::istream &	in,
		int16 &	data
	)			[static]

Read a int16 (2 bytes).

Parameters:

	in	input stream
	data	variable where the data should be stored

Returns:

a reference to the variable with the readed data

template<eEndiannessType E>

static bool cvr::endianness< E >::read	(	std::istream &	in,
		ubyte &	data
	)			[static]

Read an unsigned byte from the stream.

Parameters:

	in	input stream
	data	variable where the data should be stored

Returns:

a reference to the variable with the readed data

template<eEndiannessType E>

static bool cvr::endianness< E >::read	(	std::istream &	in,
		byte &	data
	)			[static]

Read a byte from the stream.

Parameters:

	in	input stream
	data	variable where the data should be stored

Returns:

a reference to the variable with the readed data

template<eEndiannessType E>

static bool cvr::endianness< E >::write	(	std::ostream &	out,
		const uint32 &	data
	)			[static]

Write a uint32.

Parameters:

	out	output stream
	data	variable with the data to be stored on the file

Returns:

a reference to the variable with the data

template<eEndiannessType E>

static bool cvr::endianness< E >::write	(	std::ostream &	out,
		const int32 &	data
	)			[static]

Write a int32.

Parameters:

	out	output stream
	data	variable with the data to be stored on the file

Returns:

a reference to the variable with the data

template<eEndiannessType E>

static bool cvr::endianness< E >::write	(	std::ostream &	out,
		const uint16 &	data
	)			[static]

Write a uint16 (2 bytes).

Parameters:

	out	output stream
	data	variable with the data to be stored on the file

Returns:

a reference to the variable with the data

template<eEndiannessType E>

static bool cvr::endianness< E >::write	(	std::ostream &	out,
		const int16 &	data
	)			[static]

Write a int16 (2 bytes).

Parameters:

	out	output stream
	data	variable with the data to be stored on the file

Returns:

a reference to the variable with the data

template<eEndiannessType E>

static bool cvr::endianness< E >::write	(	std::ostream &	out,
		const ubyte &	data
	)			[static]

Write a ubyte.

Parameters:

	out	output stream
	data	variable with the data to be stored on the file

Returns:

a reference to the variable with the data

template<eEndiannessType E>

static bool cvr::endianness< E >::write	(	std::ostream &	out,
		const byte &	data
	)			[static]

Write a byte.

Parameters:

	out	output stream
	data	variable with the data to be stored on the file

Returns:

a reference to the variable with the data

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The documentation for this class was generated from the following file:

• cvrEndianness.h