예제 #1
0
        /// <summary>
        /// Parse hexadecimal field
        /// </summary>
        protected bool ParseHexadecimal(TextParser input, FormatSpecifier spec)
        {
            // Skip any whitespace
            input.MovePastWhitespace();

            // Parse 0x prefix
            int start = input.Position;

            if (input.Peek() == '0' && input.Peek(1) == 'x')
            {
                input.MoveAhead(2);
            }

            // Parse digits
            while (IsValidDigit(input.Peek(), 16))
            {
                input.MoveAhead();
            }

            // Don't exceed field width
            if (spec.Width > 0)
            {
                int count = input.Position - start;
                if (spec.Width < count)
                {
                    input.MoveAhead(spec.Width - count);
                }
            }

            // Extract token
            if (input.Position > start)
            {
                if (!spec.NoResult)
                {
                    AddUnsigned(input.Extract(start, input.Position), spec.Modifier, 16);
                }
                return(true);
            }
            return(false);
        }
예제 #2
0
        /// <summary>
        /// Parse integer field
        /// </summary>
        private bool ParseDecimal(TextParser input, FormatSpecifier spec)
        {
            int radix = 10;

            // Skip any whitespace
            input.MovePastWhitespace();

            // Parse leading sign
            int start = input.Position;

            if (input.Peek() == '+' || input.Peek() == '-')
            {
                input.MoveAhead();
            }
            else if (input.Peek() == '0')
            {
                if (Char.ToLower(input.Peek(1)) == 'x')
                {
                    radix = 16;
                    input.MoveAhead(2);
                }
                else
                {
                    radix = 8;
                    input.MoveAhead();
                }
            }

            // Parse digits
            while (IsValidDigit(input.Peek(), radix))
            {
                input.MoveAhead();
            }

            // Don't exceed field width
            if (spec.Width > 0)
            {
                int count = input.Position - start;
                if (spec.Width < count)
                {
                    input.MoveAhead(spec.Width - count);
                }
            }

            // Extract token
            if (input.Position > start)
            {
                if (!spec.NoResult)
                {
                    if (spec.Type == Types.Decimal)
                    {
                        AddSigned(input.Extract(start, input.Position), spec.Modifier, radix);
                    }
                    else
                    {
                        AddUnsigned(input.Extract(start, input.Position), spec.Modifier, radix);
                    }
                }
                return(true);
            }
            return(false);
        }
예제 #3
0
        /// <summary>
        /// Parse a floating-point field
        /// </summary>
        private bool ParseFloat(TextParser input, FormatSpecifier spec)
        {
            // Skip any whitespace
            input.MovePastWhitespace();

            // Parse leading sign
            int start = input.Position;

            if (input.Peek() == '+' || input.Peek() == '-')
            {
                input.MoveAhead();
            }

            // Parse digits
            bool hasPoint = false;

            while (Char.IsDigit(input.Peek()) || input.Peek() == '.')
            {
                if (input.Peek() == '.')
                {
                    if (hasPoint)
                    {
                        break;
                    }
                    hasPoint = true;
                }
                input.MoveAhead();
            }

            // Parse exponential notation
            if (Char.ToLower(input.Peek()) == 'e')
            {
                input.MoveAhead();
                if (input.Peek() == '+' || input.Peek() == '-')
                {
                    input.MoveAhead();
                }
                while (Char.IsDigit(input.Peek()))
                {
                    input.MoveAhead();
                }
            }

            // Don't exceed field width
            if (spec.Width > 0)
            {
                int count = input.Position - start;
                if (spec.Width < count)
                {
                    input.MoveAhead(spec.Width - count);
                }
            }

            // Because we parse the exponential notation before we apply
            // any field-width constraint, it becomes awkward to verify
            // we have a valid floating point token. To prevent an
            // exception, we use TryParse() here instead of Parse().
            double result;

            // Extract token
            if (input.Position > start &&
                double.TryParse(input.Extract(start, input.Position), out result))
            {
                if (!spec.NoResult)
                {
                    if (spec.Modifier == Modifiers.Long ||
                        spec.Modifier == Modifiers.LongLong)
                    {
                        Results.Add(result);
                    }
                    else
                    {
                        Results.Add((float)result);
                    }
                }
                return(true);
            }
            return(false);
        }
예제 #4
0
        /// <summary>
        /// Attempts to parse a field format specifier from the format string.
        /// </summary>
        protected bool ParseFormatSpecifier(TextParser format, FormatSpecifier spec)
        {
            // Return if not a field format specifier
            if (format.Peek() != '%')
            {
                return(false);
            }
            format.MoveAhead();

            // Return if "%%" (treat as '%' literal)
            if (format.Peek() == '%')
            {
                return(false);
            }

            // Test for asterisk, which indicates result is not stored
            if (format.Peek() == '*')
            {
                spec.NoResult = true;
                format.MoveAhead();
            }
            else
            {
                spec.NoResult = false;
            }

            // Parse width
            int start = format.Position;

            while (Char.IsDigit(format.Peek()))
            {
                format.MoveAhead();
            }
            if (format.Position > start)
            {
                spec.Width = int.Parse(format.Extract(start, format.Position));
            }
            else
            {
                spec.Width = 0;
            }

            // Parse modifier
            if (format.Peek() == 'h')
            {
                format.MoveAhead();
                if (format.Peek() == 'h')
                {
                    format.MoveAhead();
                    spec.Modifier = Modifiers.ShortShort;
                }
                else
                {
                    spec.Modifier = Modifiers.Short;
                }
            }
            else if (Char.ToLower(format.Peek()) == 'l')
            {
                format.MoveAhead();
                if (format.Peek() == 'l')
                {
                    format.MoveAhead();
                    spec.Modifier = Modifiers.LongLong;
                }
                else
                {
                    spec.Modifier = Modifiers.Long;
                }
            }
            else
            {
                spec.Modifier = Modifiers.None;
            }

            // Parse type
            switch (format.Peek())
            {
            case 'c':
                spec.Type = Types.Character;
                break;

            case 'd':
            case 'i':
                spec.Type = Types.Decimal;
                break;

            case 'a':
            case 'A':
            case 'e':
            case 'E':
            case 'f':
            case 'F':
            case 'g':
            case 'G':
                spec.Type = Types.Float;
                break;

            case 'o':
                spec.Type = Types.Octal;
                break;

            case 's':
                spec.Type = Types.String;
                break;

            case 'u':
                spec.Type = Types.Unsigned;
                break;

            case 'x':
            case 'X':
                spec.Type = Types.Hexadecimal;
                break;

            case '[':
                spec.Type = Types.ScanSet;
                format.MoveAhead();
                // Parse scan set characters
                if (format.Peek() == '^')
                {
                    spec.ScanSetExclude = true;
                    format.MoveAhead();
                }
                else
                {
                    spec.ScanSetExclude = false;
                }
                start = format.Position;
                // Treat immediate ']' as literal
                if (format.Peek() == ']')
                {
                    format.MoveAhead();
                }
                format.MoveTo(']');
                if (format.EndOfText)
                {
                    throw new Exception("Type specifier expected character : ']'");
                }
                spec.ScanSet = format.Extract(start, format.Position);
                break;

            default:
                string msg = String.Format("Unknown format type specified : '{0}'", format.Peek());
                throw new Exception(msg);
            }
            format.MoveAhead();
            return(true);
        }