/// <inheritdoc cref="TryParseInt(string, ref int, out int, int, bool)"/>
public static bool TryParseInt(ref UString input, out long result, int radix = 10, ParseFlag flags = 0)
{
if ((flags & ParseFlag.SkipSpacesInFront) != 0)
{
input = SkipSpaces(input);
}
UString s = input;
bool negative = false;
char c = s[0, '\0'];
if (c == '-' || c == '+')
{
negative = c == '-';
s = s.Slice(1);
}
ulong resultU = 0;
int numDigits;
bool ok = TryParseUInt(ref s, ref resultU, radix, flags, out numDigits);
result = negative ? -(long)resultU : (long)resultU;
if (numDigits != 0)
{
input = s;
}
return(ok && ((result < 0) == negative || result == 0));
}
/// <summary>Returns a string with any spaces and tabs removed from the beginning.</summary>
public static UString SkipSpaces(UString s)
{
char c;
while ((c = s[0, '\0']) == ' ' || c == '\t')
{
s = s.Slice(1);
}
return(s);
}
static bool TryParseUInt(ref UString s, ref ulong result, int radix, ParseFlag flags, out int numDigits)
{
numDigits = 0;
if ((flags & ParseFlag.SkipSpacesInFront) != 0)
{
s = SkipSpaces(s);
}
bool overflow = false;
int oldStart = s.InternalStart;
for (;; s = s.Slice(1))
{
char c = s[0, '\0'];
uint digit = (uint)Base36DigitValue(c);
if (digit >= radix)
{
if ((c == ' ' || c == '\t') && (flags & ParseFlag.SkipSpacesInsideNumber) != 0)
{
continue;
}
else if (c == '_' && (flags & ParseFlag.SkipUnderscores) != 0)
{
continue;
}
else
{
break;
}
}
ulong next;
try {
next = checked (result * (uint)radix + digit);
} catch (OverflowException) {
overflow = true;
if ((flags & ParseFlag.StopBeforeOverflow) != 0)
{
return(false);
}
next = result * (uint)radix + digit;
}
numDigits++;
result = next;
}
return(!overflow && numDigits > 0);
}
public static int TryParseHex(ref UString s, out int value)
{
value = 0;
int len = 0;
for (;; len++, s = s.Slice(1))
{
int digit = HexDigitValue(s[0, '\0']);
if (digit == -1)
{
return(len);
}
else
{
value = value * 16 + digit;
}
}
}
private static int SkipExtraDigits(ref UString s, int radix, ParseFlag flags)
{
for (int skipped = 0;; skipped++, s = s.Slice(1))
{
char c = s[0, '\0'];
uint digit = (uint)Base36DigitValue(c);
if (digit >= radix)
{
if ((c == ' ' || c == '\t') && (flags & ParseFlag.SkipSpacesInsideNumber) != 0)
{
continue;
}
else if (c == '_' && (flags & ParseFlag.SkipUnderscores) != 0)
{
continue;
}
else
{
return(skipped);
}
}
}
}
/// <summary>Low-level method that identifies the parts of a float literal
/// of arbitrary base (typically base 2, 10, or 16) with no prefix or
/// suffix, such as <c>2.Cp0</c> (which means 2.75 in base 16).</summary>
/// <param name="radix">Base of the number to parse; must be between 2
/// and 36.</param>
/// <param name="mantissa">Integer magnitude of the number.</param>
/// <param name="exponentBase2">Base-2 exponent to apply, as specified by
/// the 'p' suffix, or 0 if there is no 'p' suffix..</param>
/// <param name="exponentBase10">Base-10 exponent to apply, as specified by
/// the 'e' suffix, or 0 if there is no 'e' suffix..</param>
/// <param name="exponentBaseR">Base-radix exponent to apply. This number
/// is based on the front part of the number only (not including the 'p' or
/// 'e' suffix). Negative values represent digits after the decimal point,
/// while positive numbers represent 64-bit overflow. For example, if the
/// input is <c>12.3456</c> with <c>radix=10</c>, the output will be
/// <c>mantissa=123456</c> and <c>exponentBaseR=-4</c>. If the input is
/// <c>0123_4567_89AB_CDEF_1234.5678</c> with <c>radix=16</c>, the mantissa
/// overflows, and the result is <c>mantissa = 0x1234_5678_9ABC_DEF1</c>
/// with <c>exponentBaseR=3</c>.</param>
/// <param name="numDigits">Set to the number of digits in the number, not
/// including the exponent part.</param>
/// <param name="flags">Alters parsing behavior, see <see cref="ParseFlags"/>.</param>
/// <remarks>
/// The syntax required is
/// <code>
/// ( '+'|'-' )?
/// ( Digits ('.' Digits?)? | '.' Digits )
/// ( ('p'|'P') ('-'|'+')? DecimalDigits+ )?
/// ( ('e'|'E') ('-'|'+')? DecimalDigits+ )?
/// </code>
/// where Digits refers to one digits in the requested base, possibly
/// including underscores or spaces if the flags allow it; similarly,
/// DecimalDigits refers to base-10 digits and is also affected by the
/// flags.
/// <para/>
/// Returns false if there was an error interpreting the input.
/// <para/>
/// To keep the parser relatively simple, it does not roll back in case of
/// error the way the int parser does. For example, given the input "23p",
/// the 'p' is consumed and causes the method to return false, even though
/// the parse could have been successful if it had ignored the 'p'.
/// </remarks>
public static bool TryParseFloatParts(ref UString source, int radix, out bool negative, out ulong mantissa, out int exponentBaseR, out int exponentBase2, out int exponentBase10, out int numDigits, ParseFlag flags = 0)
{
flags |= G.ParseFlag.StopBeforeOverflow;
if ((flags & ParseFlag.SkipSpacesInFront) != 0)
{
source = SkipSpaces(source);
}
negative = false;
char c = source[0, '\0'];
if (c == '-' || c == '+')
{
negative = c == '-';
source = source.Slice(1);
}
int numDigits2 = 0;
mantissa = 0;
exponentBase2 = 0;
exponentBase10 = 0;
exponentBaseR = 0;
bool success = TryParseUInt(ref source, ref mantissa, radix, flags, out numDigits);
if (!success) // possible overflow, extra digits remain if so
{
numDigits += (exponentBaseR = SkipExtraDigits(ref source, radix, flags));
}
c = source[0, '\0'];
if (c == '.' || (c == ',' && (flags & ParseFlag.AllowCommaDecimalPoint) != 0))
{
source = source.Slice(1);
if (exponentBaseR == 0)
{
success = TryParseUInt(ref source, ref mantissa, radix, flags, out numDigits2);
if ((numDigits += numDigits2) == 0)
{
return(false);
}
exponentBaseR = -numDigits2;
}
else
{
Debug.Assert(!success);
}
if (!success) // possible overflow, extra digits remain if so
{
numDigits += SkipExtraDigits(ref source, radix, flags);
}
c = source[0, '\0'];
}
if (numDigits == 0)
{
return(false);
}
success = true;
if (c == 'p' || c == 'P')
{
source = source.Slice(1);
success = TryParseInt(ref source, out exponentBase2, 10, flags) && success;
c = source[0, '\0'];
}
if (c == 'e' || c == 'E')
{
source = source.Slice(1);
success = TryParseInt(ref source, out exponentBase10, 10, flags) && success;
}
return(success);
}
