/// <summary>
/// Matches Int32 values that must not start with '0' ('0' is valid but '0d', where d is any digit, is not).
/// A signed integer starts with a '-'. '-0' is valid but '-0d' (where d is any digit) is not.
/// If the value is too big for an Int32, it fails.
/// </summary>
/// <param name="this">This <see cref="IStringMatcher"/>.</param>
/// <param name="i">The result integer. 0 on failure.</param>
/// <param name="minValue">Optional minimal value.</param>
/// <param name="maxValue">Optional maximal value.</param>
/// <returns><c>true</c> when matched, <c>false</c> otherwise.</returns>
public static bool MatchInt32(this IStringMatcher @this, out int i, int minValue = int.MinValue, int maxValue = int.MaxValue)
{
i = 0;
long savedIndex = @this.StartIndex;
long value = 0;
bool signed;
if (@this.IsEnd)
{
return(@this.SetError());
}
if ((signed = @this.TryMatchChar('-')) && @this.IsEnd)
{
return(@this.BackwardAddError(savedIndex));
}
char c;
if (@this.TryMatchChar('0'))
{
if ([email protected] && (c = @this.Head) >= '0' && c <= '9')
{
return(@this.BackwardAddError(savedIndex, "0...9"));
}
return(@this.ClearError());
}
unchecked
{
long iMax = Int32.MaxValue;
if (signed)
{
iMax = iMax + 1;
}
while ([email protected] && (c = @this.Head) >= '0' && c <= '9')
{
value = value * 10 + (c - '0');
if (value > iMax)
{
break;
}
@this.UncheckedMove(1);
}
}
if (@this.StartIndex > savedIndex)
{
if (signed)
{
value = -value;
}
if (value < minValue || value > maxValue)
{
return(@this.BackwardAddError(savedIndex, String.Format(CultureInfo.InvariantCulture, "value between {0} and {1}", minValue, maxValue)));
}
i = (int)value;
return(@this.ClearError());
}
return(@this.SetError());
}