package text;

public class Convert {
	public static String toString( char value ) {
		switch ( value ) {
			case '\b':
				return "\\b";
			case '\f':
				return "\\f";
			case '\n':
				return "\\n";
			case '\r':
				return "\\r";
			case '\t':
				return "\\t";
			case '\\':
			case '\"':
			case '\'':
				return "\\" + value;
			default:
				if ( value < 32 || value >= 127 )
					return "\\" + toOctalString( value );
				else
					return "" + value;
			}
		}

	public static String toString( String s ) {
		String result = "";
		for ( int i = 0; i < s.length(); i++ )
			result += toString( s.charAt( i ) );
		return result;
		}

	public static String toOctalString( char value ) {
		String result = "";
		result += value / 64;
		value %= 64;
		result += value / 8;
		value %= 8;
		result += value;
		return result;
		}
		
	public static String parseString( String input ) {
		String output = "";
		int i = 0;
		char inputChar;
		char outputChar;
		while ( i < input.length() ) {
			inputChar = input.charAt( i );
			if ( inputChar == '\\' ) {
				i++;
				if ( i >= input.length() )
					throw new Error( "Invalid Text String" );
				inputChar = input.charAt( i );
				switch ( inputChar ) {
					case 'b':
						output += '\b';
						i++;
						break;
					case 'f':
						output += '\f';
						i++;
						break;
					case 'n':
						output += '\n';
						i++;
						break;
					case 'r':
						output += '\r';
						i++;
						break;
					case 't':
						output += '\t';
						i++;
						break;
					case 'x':
					case 'X':
					case 'u':
						{
						outputChar = 0;
						i++;
						for ( int j = 0; i < input.length() && j < 2; j ++ ) {
							inputChar = input.charAt( i );
							if ( inputChar >= '0' && inputChar <= '9' ) {
								outputChar = ( char ) ( outputChar * 0x10 + inputChar - '0' );
								i++;
								}
							else if ( inputChar >= 'a' && inputChar <= 'f' ) {
								outputChar = ( char ) ( outputChar * 0x10 + inputChar - 'a' + 0xa );
								i++;
								}
							else if ( inputChar >= 'A' && inputChar <= 'F' ) {
								outputChar = ( char ) ( outputChar * 0x10 + inputChar - 'A' + 0xa );
								i++;
								}
							else
								break;
							}
						output += outputChar;
						} // end while loop
						break;
					case '0':
					case '1':
					case '2':
					case '3':
					case '4':
					case '5':
					case '6':
					case '7':
						{
						outputChar = 0;
						for ( int j = 0; i < input.length() && j < 3; j ++ ) {
							inputChar = input.charAt( i );
							if ( inputChar >= '0' && inputChar <= '7' ) {
								outputChar = ( char ) ( outputChar * 010 + inputChar - '0' );
								i++;
								}
							else
								break;
							} // end while loop
						output += outputChar;
						}
						break;
					default:
						output += inputChar;
						i++;
					} // end cases
				} // end then
			else if ( inputChar == '%' ) {
				output += "%%";
				i++;
				}
			else {
				output += inputChar;
				i++;
				}
			} // end while loop
		return output;
		}

	public static Character parseChar( String input ) {
		String output = parseString( input );
		if ( output.length() == 1 )
			return new Character( output.charAt( 0 ) );
		else
			throw new Error( "Invalid Text String" );
		}
	}