public static bool TryParseSByte(ReadOnlySpan <byte> text, out sbyte value, out int bytesConsumed, TextFormat format = default, SymbolTable symbolTable = null)
{
symbolTable = symbolTable ?? SymbolTable.InvariantUtf8;
if (!format.IsDefault && format.HasPrecision)
{
throw new NotImplementedException("Format with precision not supported.");
}
if (symbolTable == SymbolTable.InvariantUtf8)
{
if (format.IsHexadecimal)
{
return(InvariantUtf8.Hex.TryParseSByte(text, out value, out bytesConsumed));
}
else
{
return(InvariantUtf8.TryParseSByte(text, out value, out bytesConsumed));
}
}
else if (symbolTable == SymbolTable.InvariantUtf16)
{
ReadOnlySpan <char> utf16Text = text.NonPortableCast <byte, char>();
int charsConsumed;
bool result;
if (format.IsHexadecimal)
{
result = InvariantUtf16.Hex.TryParseSByte(utf16Text, out value, out charsConsumed);
}
else
{
result = InvariantUtf16.TryParseSByte(utf16Text, out value, out charsConsumed);
}
bytesConsumed = charsConsumed * sizeof(char);
return(result);
}
if (format.IsHexadecimal)
{
throw new NotImplementedException("The only supported encodings for hexadecimal parsing are InvariantUtf8 and InvariantUtf16.");
}
if (!(format.IsDefault || format.Symbol == 'G' || format.Symbol == 'g'))
{
throw new NotImplementedException(String.Format("Format '{0}' not supported.", format.Symbol));
}
SymbolTable.Symbol nextSymbol;
int thisSymbolConsumed;
if (!symbolTable.TryParse(text, out nextSymbol, out thisSymbolConsumed))
{
value = default;
bytesConsumed = 0;
return(false);
}
int sign = 1;
if (nextSymbol == SymbolTable.Symbol.MinusSign)
{
sign = -1;
}
int signConsumed = 0;
if (nextSymbol == SymbolTable.Symbol.PlusSign || nextSymbol == SymbolTable.Symbol.MinusSign)
{
signConsumed = thisSymbolConsumed;
if (!symbolTable.TryParse(text.Slice(signConsumed), out nextSymbol, out thisSymbolConsumed))
{
value = default;
bytesConsumed = 0;
return(false);
}
}
if (nextSymbol > SymbolTable.Symbol.D9)
{
value = default;
bytesConsumed = 0;
return(false);
}
int parsedValue = (int)nextSymbol;
int index = signConsumed + thisSymbolConsumed;
while (index < text.Length)
{
bool success = symbolTable.TryParse(text.Slice(index), out nextSymbol, out thisSymbolConsumed);
if (!success || nextSymbol > SymbolTable.Symbol.D9)
{
bytesConsumed = index;
value = (sbyte)(parsedValue * sign);
return(true);
}
// If parsedValue > (sbyte.MaxValue / 10), any more appended digits will cause overflow.
// if parsedValue == (sbyte.MaxValue / 10), any nextDigit greater than 7 or 8 (depending on sign) implies overflow.
bool positive = sign > 0;
bool nextDigitTooLarge = nextSymbol > SymbolTable.Symbol.D8 || (positive && nextSymbol > SymbolTable.Symbol.D7);
if (parsedValue > sbyte.MaxValue / 10 || (parsedValue == sbyte.MaxValue / 10 && nextDigitTooLarge))
{
bytesConsumed = 0;
value = default;
return(false);
}
index += thisSymbolConsumed;
parsedValue = parsedValue * 10 + (int)nextSymbol;
}
bytesConsumed = text.Length;
value = (sbyte)(parsedValue * sign);
return(true);
}
public static bool TryParseInt32(ReadOnlySpan <byte> text, out int value, out int bytesConsumed, TextFormat format = default, SymbolTable symbolTable = null)
{
bool isDefault = format.IsDefault;
symbolTable = symbolTable ?? SymbolTable.InvariantUtf8;
if (!isDefault && format.HasPrecision)
{
throw new NotImplementedException("Format with precision not supported.");
}
bool isHex = format.IsHexadecimal;
if (symbolTable == SymbolTable.InvariantUtf8)
{
return(isHex ? InvariantUtf8.Hex.TryParseInt32(text, out value, out bytesConsumed) :
InvariantUtf8.TryParseInt32(text, out value, out bytesConsumed));
}
else if (symbolTable == SymbolTable.InvariantUtf16)
{
/*return isHex ? InvariantUtf16.Hex.TryParseInt32(text, out value, out bytesConsumed) :
* InvariantUtf16.TryParseInt32(text, out value, out bytesConsumed);*/
ReadOnlySpan <char> utf16Text = text.NonPortableCast <byte, char>();
bool result = isHex ? InvariantUtf16.Hex.TryParseInt32(utf16Text, out value, out int charsConsumed) :
InvariantUtf16.TryParseInt32(utf16Text, out value, out charsConsumed);
bytesConsumed = charsConsumed * sizeof(char);
return(result);
}
if (isHex)
{
throw new NotImplementedException("The only supported encodings for hexadecimal parsing are InvariantUtf8 and InvariantUtf16.");
}
if (!(isDefault || format.Symbol == 'G' || format.Symbol == 'g'))
{
throw new NotImplementedException(String.Format("Format '{0}' not supported.", format.Symbol));
}
int textLength = text.Length;
if (textLength < 1)
{
goto FalseExit;
}
if (!symbolTable.TryParse(text, out SymbolTable.Symbol symbol, out int consumed))
{
goto FalseExit;
}
sbyte sign = 1;
int index = 0;
if (symbol == SymbolTable.Symbol.MinusSign)
{
sign = -1;
index += consumed;
if (index >= textLength)
{
goto FalseExit;
}
if (!symbolTable.TryParse(text.Slice(index), out symbol, out consumed))
{
goto FalseExit;
}
}
else if (symbol == SymbolTable.Symbol.PlusSign)
{
index += consumed;
if (index >= textLength)
{
goto FalseExit;
}
if (!symbolTable.TryParse(text.Slice(index), out symbol, out consumed))
{
goto FalseExit;
}
}
int answer = 0;
if (IsValid(symbol))
{
int numBytes = consumed;
if (symbol == SymbolTable.Symbol.D0)
{
do
{
index += consumed;
if (index >= textLength)
{
goto Done;
}
if (!symbolTable.TryParse(text.Slice(index), out symbol, out consumed))
{
goto Done;
}
} while (symbol == SymbolTable.Symbol.D0);
if (!IsValid(symbol))
{
goto Done;
}
}
int firstNonZeroDigitIndex = index;
if (textLength - firstNonZeroDigitIndex < Int32OverflowLength * numBytes)
{
do
{
answer = answer * 10 + (int)symbol;
index += consumed;
if (index >= textLength)
{
goto Done;
}
if (!symbolTable.TryParse(text.Slice(index), out symbol, out consumed))
{
goto Done;
}
} while (IsValid(symbol));
}
else
{
do
{
answer = answer * 10 + (int)symbol;
index += consumed;
if (index - firstNonZeroDigitIndex == (Int32OverflowLength - 1) * numBytes)
{
if (!symbolTable.TryParse(text.Slice(index), out symbol, out consumed))
{
goto Done;
}
if (IsValid(symbol))
{
if (WillOverFlow(answer, (int)symbol, sign))
{
goto FalseExit;
}
answer = answer * 10 + (int)symbol;
index += consumed;
}
goto Done;
}
if (!symbolTable.TryParse(text.Slice(index), out symbol, out consumed))
{
goto Done;
}
} while (IsValid(symbol));
}
goto Done;
}
FalseExit:
bytesConsumed = 0;
value = 0;
return(false);
Done:
bytesConsumed = index;
value = answer * sign;
return(true);
}