レーベンシュタインコーディング

void levenshteinEncode ( char * source , char * dest ) { IntReader intreader ( source ); BitWriter bitwriter ( dest ); while ( intreader . hasLeft ()) { int num = intreader . getInt (); if ( num == 0 ) bitwriter . outputBit ( 0 ); else { int c = 0 ; BitStack bits ; do { int m = 0 ; for ( int temp = num ; temp > 1 ; temp >>= 1 ) // floor(log2(num)) ++ mを計算します。for ( int i = 0 ; i < m ; ++ i ) bits . pushBit (( num >> i ) & 1 ); num = m ; ++ c ; } while ( num > 0 ); for ( int i = 0 ; i < c ; ++ i ) bitwriter . outputBit ( 1 ); bitwriter . outputBit ( 0 ); while ( bits . length () > 0 ) bitwriter . outputBit ( bits . popBit ()); } } }    

     
     
     
    
           
           
            
        
        
               
             
             
                   
                          
                    
                      
                        
                  
                
                
                  
                
            
               
                
        
    

void levenshteinDecode ( char * source , char * dest ) { BitReader bitreader ( source ); IntWriter intwriter ( dest ); while ( bitreader . hasLeft ()) { int n = 0 ; while ( bitreader . inputBit ()) // 不正なファイルの場合、潜在的に危険です。++ n ; int num ; if ( n == 0 ) num = 0 ; else { num = 1 ; for ( int i = 0 ; i < n -1 ; ++ i ) { int val = 1 ; for ( int j = 0 ; j < num ; ++ j ) val = ( val << 1 ) | bitreader . inputBit (); num = val ; } } intwriter . putInt ( num ); // 値を書き出します} bitreader . close (); intwriter .close ( ); }