RosettaCodeData/Task/Substitution-cipher/C++/substitution-cipher.cpp

71 lines
2.3 KiB
C++

#include <iostream>
#include <string>
#include <fstream>
class cipher {
public:
bool work( std::string e, std::string f, std::string k ) {
if( e.length() < 1 ) return false;
fileBuffer = readFile( f );
if( "" == fileBuffer ) return false;
keyBuffer = readFile( k );
if( "" == keyBuffer ) return false;
outName = f;
outName.insert( outName.find_first_of( "." ), "_out" );
switch( e[0] ) {
case 'e': return encode();
case 'd': return decode();
}
return false;
}
private:
bool encode() {
size_t idx, len = keyBuffer.length() >> 1;
for( std::string::iterator i = fileBuffer.begin(); i != fileBuffer.end(); i++ ) {
idx = keyBuffer.find_first_of( *i );
if( idx < len ) outBuffer.append( 1, keyBuffer.at( idx + len ) );
else outBuffer.append( 1, *i );
}
return saveOutput();
}
bool decode() {
size_t idx, l = keyBuffer.length(), len = l >> 1;
for( std::string::iterator i = fileBuffer.begin(); i != fileBuffer.end(); i++ ) {
idx = keyBuffer.find_last_of( *i );
if( idx >= len && idx < l ) outBuffer.append( 1, keyBuffer.at( idx - len ) );
else outBuffer.append( 1, *i );
}
return saveOutput();
}
bool saveOutput() {
std::ofstream o( outName.c_str() );
o.write( outBuffer.c_str(), outBuffer.size() );
o.close();
return true;
}
std::string readFile( std::string fl ) {
std::string buffer = "";
std::ifstream f( fl.c_str(), std::ios_base::in );
if( f.good() ) {
buffer = std::string( ( std::istreambuf_iterator<char>( f ) ), std::istreambuf_iterator<char>() );
f.close();
}
return buffer;
}
std::string fileBuffer, keyBuffer, outBuffer, outName;
};
int main( int argc, char* argv[] ) {
if( argc < 4 ) {
std::cout << "<d or e>\tDecrypt or Encrypt\n<filename>\tInput file, the output file will have"
"'_out' added to it.\n<key>\t\tfile with the key to encode/decode\n\n";
} else {
cipher c;
if( c.work( argv[1], argv[2], argv[3] ) ) std::cout << "\nFile successfully saved!\n\n";
else std::cout << "Something went wrong!\n\n";
}
return 0;
}