/// <summary>
/// Parse a string field
/// </summary>
private bool ParseString(TextParser input, FormatSpecifier spec)
{
// Skip any whitespace
input.MovePastWhitespace();
// Parse string characters
int start = input.Position;
while (!input.EndOfText && !Char.IsWhiteSpace(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);
}
// Extract token
if (input.Position > start)
{
if (!spec.NoResult)
Results.Add(input.Extract(start, input.Position));
return true;
}
return false;
}
/// <summary>
/// Parses the input string according to the rules in the
/// format string. Similar to the standard C library's
/// sscanf() function. Parsed fields are placed in the
/// class' Results member.
/// </summary>
/// <param name="input">String to parse</param>
/// <param name="format">Specifies rules for parsing input</param>
public int Parse(string input, string format)
{
TextParser inp = new TextParser(input);
TextParser fmt = new TextParser(format);
List<object> results = new List<object>();
FormatSpecifier spec = new FormatSpecifier();
int count = 0;
// Clear any previous results
Results.Clear();
// Process input string as indicated in format string
while (!fmt.EndOfText && !inp.EndOfText)
{
if (ParseFormatSpecifier(fmt, spec))
{
// Found a format specifier
TypeParser parser = _typeParsers.First(tp => tp.Type == spec.Type);
if (parser.Parser(inp, spec))
count++;
else
break;
}
else if (Char.IsWhiteSpace(fmt.Peek()))
{
// Whitespace
inp.MovePastWhitespace();
fmt.MoveAhead();
}
else if (fmt.Peek() == inp.Peek())
{
// Matching character
inp.MoveAhead();
fmt.MoveAhead();
}
else break; // Break at mismatch
}
// Return number of fields successfully parsed
return count;
}
/// <summary>
/// Parse an octal field
/// </summary>
private bool ParseOctal(TextParser input, FormatSpecifier spec)
{
// Skip any whitespace
input.MovePastWhitespace();
// Parse digits
int start = input.Position;
while (IsValidDigit(input.Peek(), 8))
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, 8);
return true;
}
return false;
}
/// <summary>
/// Parse a scan-set field
/// </summary>
protected bool ParseScanSet(TextParser input, FormatSpecifier spec)
{
// Parse characters
int start = input.Position;
if (!spec.ScanSetExclude)
{
while (spec.ScanSet.Contains(input.Peek()))
input.MoveAhead();
}
else
{
while (!input.EndOfText && !spec.ScanSet.Contains(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);
}
// Extract token
if (input.Position > start)
{
if (!spec.NoResult)
Results.Add(input.Extract(start, input.Position));
return true;
}
return false;
}
/// <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;
}
/// <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;
}
/// <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;
}
/// <summary>
/// Parse a character field
/// </summary>
private bool ParseCharacter(TextParser input, FormatSpecifier spec)
{
// Parse character(s)
int start = input.Position;
int count = (spec.Width > 1) ? spec.Width : 1;
while (!input.EndOfText && count-- > 0)
input.MoveAhead();
// Extract token
if (count <= 0 && input.Position > start)
{
if (!spec.NoResult)
{
string token = input.Extract(start, input.Position);
if (token.Length > 1)
Results.Add(token.ToCharArray());
else
Results.Add(token[0]);
}
return true;
}
return false;
}
/// <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;
}