private List <CharPartRange> canonicalized(List <CharClassPart> e)
{
List <CharPartRange> l2 = new List <CharPartRange>();
foreach (CharClassPart c in e)
{
if (c is CharPartSingle)
{
CharPartSingle cs = c as CharPartSingle;
l2.Add(new CharPartRange(cs.Ch, cs.Ch));
}
else if (c is CharPartRange)
{
CharPartRange cr = c as CharPartRange;
if (cr.From > cr.To)
{
cr = new CharPartRange(cr.To, cr.From);
}
l2.Add(cr);
}
else
{
throw new ArgumentException(c.ToString());
}
}
l2.Sort((a, b) => a.From.CompareTo(b.From));
return(l2);
}
private List <Trans> charRange(CharClass cc)
{
List <Trans> ret = new List <Trans>();
foreach (CharClassPart _cr in cc.Parts)
{
// Assumes the CharClass has been canonicalized
// i.e all parts are ranges
CharPartRange cr = _cr as CharPartRange;
ret.Add(new CharRange(cr.From, cr.To));
}
return(ret);
}
private CharClass canonicalized(NotCharClass e)
{
/*
* Here we convert something like [^a-zA-Z] into a vector of CharPartRange objects
* we start with the 'any char' range, from 0 to 0xffff, and we subtract each CharClassPart in turn
*/
// todo:
// Since the code tries to simplify things by converting
// all CharClassPart objects into ranges, we will treat 'Any'
// as a range from 0 to 0xffff (the maximum value for a char, i.e 16-bit Unicode)
// this probably wreaks havoc with internationalization, but we're using chars
// and ignoring anything more than 16bit for now anyway. If we later use a more advanced library
// we need to deal with 'Any' and 'Not' for CharClasses in a more general
// (and encoding independent) way.
// Note that the code below assumes the 'excluded' vector is sorted
// which is provided by the called other canonicalized(..) function
List <CharPartRange> excluded = canonicalized(e.Parts);
List <CharClassPart> result = new List <CharClassPart>();
int start = 0, end = 0xffff;
for (int i = 0; i < excluded.Count; ++i)
{
CharPartRange r = excluded[i];
// It is important for a, b to be SIGNED ints, so that From.unicode()-1 can be negative
// and To.unicode()+1 doesn't wrap around
int a = start, b = r.From - 1;
if (valid(a, b))
{
result.Add(new CharPartRange((char)a, (char)b));
}
start = r.To + 1;
}
int aa = start, bb = end;
if (valid(aa, bb))
{
result.Add(new CharPartRange((char)aa, (char)bb));
}
return(new CharClass(result));
}