public int?CheckValidity(bool canThrow = true)
{
var parentheses = new Stack <int>();
int bracketDeep = 0;
int parentheseDeep = 0;
for (int i = 0; i < EncodedString.Length; i++)
{
var chr = EncodedString[i];
if (chr == '#' || chr == '~')
{
if (i + 1 >= EncodedString.Length || !char.IsDigit(EncodedString[i + 1]))
{
if (canThrow)
{
throw new InvalidPatternException("Attempt a digit after '" + chr + "'", i);
}
else
{
return(i);
}
}
}
if (chr == '{')
{
bracketDeep++;
}
else if (chr == '}')
{
bracketDeep--;
}
if (chr == '[')
{
parentheseDeep++;
parentheses.Push(i);
}
else if (chr == ']')
{
parentheseDeep--;
int last = parentheses.Pop();
var sub = EncodedString.Substring(i + 1, last - 1 - i);
if (string.IsNullOrEmpty(sub) || !sub.All(char.IsDigit))
{
if (canThrow)
{
throw new InvalidPatternException("Attempt a number between [ and ]", last);
}
else
{
return(i);
}
}
}
}
if (bracketDeep != 0)
{
if (canThrow)
{
throw new InvalidPatternException("'{' not closed");
}
else
{
return(0);
}
}
if (parentheseDeep != 0)
{
if (canThrow)
{
throw new InvalidPatternException("'[' not closed");
}
else
{
return(0);
}
}
return(null);
}