public void addRangeTransitionsToDFA(
Dictionary <RangeTransition <T>, int> dfaTransitions,
Dictionary <int, RegexTrie <T> > allDTries,
RegexTrie <T> origin)
{
foreach (var trans in dfaTransitions)
{
if (!allDTries.ContainsKey(trans.Value))
{
allDTries[trans.Value] = new RegexTrie <T>();
}
RegexTrie <T> target = allDTries[trans.Value];
origin.AddRangeTransition(
target, trans.Key.rangeStart, trans.Key.rangeEnd, trans.Key.groupNumber);
}
}
//Add transitions from a square bracket group between the tries given as arguments.
//Returns the amount of characters consumed from the input string (so the string index can be incremented).
private int handleSquareBracketGroup(RegexTrie <T> sourceTrie, RegexTrie <T> targetTrie, string sourceTail)
{
Boolean isEscaped = false;
Boolean isComplement = false;
//The complement transition to build
ComplementTransition <T> complement = new ComplementTransition <T>(0, targetTrie);
//Check whether this is a complement set
if (sourceTail[0] == '^')
{
//Add complement transition to trie
sourceTrie.complementTransitions.Add(complement);
isComplement = true;
sourceTail = sourceTail.Substring(1);
}
StringBuilder set = new StringBuilder();
char currentChar;
//First build a string out of the expression, then add every char in it or its complement to the trie
//as transitions
for (int stringIndex = 0; stringIndex < sourceTail.Length; stringIndex++)
{
currentChar = sourceTail[stringIndex];
if (isEscaped)
{
set = handleEscaped(set, currentChar);
isEscaped = false;
continue;
}
switch (currentChar)
{
case '\\':
{
isEscaped = true;
break;
}
case '-':
{
char start = sourceTail[stringIndex - 1];
char end = sourceTail[stringIndex + 1];
//Add a range transition, which can be a complement
if (isComplement)
{
complement.ranges.Add(new KeyValuePair <char, char>(start, end));
}
else
{
sourceTrie.AddRangeTransition(
targetTrie,
start,
end,
0);
}
//Remove the range start from set
set.Remove(set.Length - 1, 1);
//skip the range end
stringIndex++;
break;
}
//Add the set or its complement as transitions
case ']':
{
string finalSet = set.ToString();
if (isComplement)
{
complement.characters.AddRange(finalSet);
//One character was consumed by the complement special character, so increment by 2
return(stringIndex + 2);
}
else
{
foreach (char c in finalSet)
{
sourceTrie.AddCharacterTransition(c, 0, targetTrie);
}
return(stringIndex + 1);
}
}
default:
{
set.Append(currentChar);
break;
}
}
}
//This should never be reached, as the regex is validated to always contain closing square bracket
return(-1);
}
