endian.h ソースファイル

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 // 
 // Copyright (c) 2003-2011, MIST Project, Nagoya University
 // All rights reserved.
 // 
 // Redistribution and use in source and binary forms, with or without modification,
 // are permitted provided that the following conditions are met:
 // 
 // 1. Redistributions of source code must retain the above copyright notice,
 // this list of conditions and the following disclaimer.
 // 
 // 2. 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.
 // 
 // 3. Neither the name of the Nagoya University 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 __INCLUDE_MIST_ENDIAN__
 #define __INCLUDE_MIST_ENDIAN__
 
 #ifndef __INCLUDE_MIST_CONF_H__
 #include "mist_conf.h"
 #endif
 
 
 // mist名前空間の始まり
 _MIST_BEGIN
 
 
 
 
 
 
 template < class T >
 union byte_array
 {
 public:
     typedef T      value_type;      
     typedef size_t size_type;       
 
 private:
     value_type value;                               
     unsigned char byte[ sizeof( value_type ) ];     
 
 public:
     byte_array( ) : value( 0 ){ }
 
 
     byte_array( const value_type v ) : value( v ){ }
 
 
     byte_array( const byte_array &v ) : value( v.value ){ }
 
 
     byte_array( const unsigned char *b )
     {
         for( size_type i = 0 ; i < sizeof( value_type ) ; i++ )
         {
             byte[ i ] = b[ i ];
         }
     }
 
     size_type length( ) const { return( sizeof( value_type ) ); }
 
     unsigned char &operator[]( size_type index ){ return( byte[ index ] ); }
 
     const unsigned char &operator[]( size_type index ) const { return( byte[ index ] ); }
 
     const value_type get_value( ) const { return( value ); }
 
     value_type set_value( const value_type &v ) { return( value = v ); }
 
     const unsigned char * get_bytes( ) const { return( byte ); }
 };
 
 
 inline bool _is_little_endian_( )
 {
     return( byte_array< unsigned short >( 1 )[ 0 ] == 1 );
 }
 
 
 inline bool _is_big_endian_( )
 {
     return( byte_array< unsigned short >( 1 )[ 0 ] == 0 );
 }
 
 
 template < class T >
 inline void swap_bytes( byte_array< T > &bytes )
 {
     typedef typename byte_array< T >::size_type size_type;
     byte_array< T > tmp( bytes );
     for( size_type i = 0 ; i < sizeof( T ) ; ++i )
     {
         bytes[ i ] = tmp[ sizeof( T ) - i - 1 ];
     }
 }
 
 
 template < class T >
 inline byte_array< T > to_current_endian( const byte_array< T > &bytes, bool from_little_endian )
 {
     static bool current_endian = _is_little_endian_( );
     if( current_endian != from_little_endian )
     {
         byte_array< T > tmp( bytes );
         swap_bytes( tmp );
         return( tmp );
     }
     else
     {
         return( bytes );
     }
 }
 
 
 template < class T >
 inline byte_array< T > from_current_endian( const byte_array< T > &bytes, bool to_little_endian )
 {
     static bool current_endian = _is_little_endian_( );
     if( current_endian != to_little_endian )
     {
         byte_array< T > tmp( bytes );
         swap_bytes( tmp );
         return( tmp );
     }
     else
     {
         return( bytes );
     }
 }
 
 
 
 //  エンディアンに関する情報の取得及び変換グループの終わり
 
 
 // mist名前空間の終わり
 _MIST_END
 
 
 #endif // __INCLUDE_MIST_ENDIAN__
 