public void parsePattern()
{
if (node != null)
{
return;
}
if (!_pattern.StartsWith("^"))
{
throw new Exception("Invalid pattern start");
}
_finished = false;
_exactQuantifierRegex = new Regex("^\\{\\s*(\\d+)\\s*\\}$");
_rangeQuantifierRegex = new Regex("^\\{\\s*(\\d*)\\s*,\\s*(\\d*)\\s*\\}$");
node = parseSubpattern(_pattern, new NSRange(1, _pattern.Length - 1), false);
_exactQuantifierRegex = null;
_rangeQuantifierRegex = null;
if (!_finished)
{
throw new Exception("Invalid pattern end");
}
}
public WTReGroup groupFromNodes(List <WTReNode> nodes, bool enclosed)
{
if ((nodes.Count == 1) && (nodes[0] is WTReGroup))
{
WTReGroup t = (WTReGroup)nodes[0];
if (t is WTReGroup)
{
t.capturing |= enclosed;
return(t);
}
}
WTReGroup g = new WTReGroup();
g.children = new List <WTReNode>(nodes);
g.capturing = enclosed;
// setup links
WTReNode prev = g.children[0];
prev.parent = g;
for (int i = 1; i < g.children.Count; i++)
{
WTReNode curr = g.children[i];
curr.parent = g;
prev.nextSibling = curr;
prev = curr;
}
return(g);
}
public WTReParser(string pattern, bool ignoreCase)
{
_pattern = pattern;
_ignoreCase = ignoreCase;
node = null;
this.parsePattern();
}
WTState processNode(WTReNode node, WTState state, int length)
{
if (node is WTReEndOfString)
{
WTState finalState = new WTState();;
finalState.isFinal = true;
WTTransition tran = new WTTransition();
tran.node = (WTReCharacterBase)node;
tran.nextState = finalState;
state.transitions.Add(tran);
return(finalState);
}
else if (node is WTReCharacterBase)
{
WTState finalState = new WTState();
WTTransition tran = new WTTransition();;
tran.node = (WTReCharacterBase)node;
tran.nextState = finalState;
state.transitions.Add(tran);
return(finalState);
}
else if (node is WTReQuantifier)
{
WTReQuantifier qtf = (WTReQuantifier)node;
WTState curState = state;
for (int i = 0; i < qtf.countFrom; i++)
{
curState = processNode(qtf.child, curState, length);
}
if (qtf.countTo == qtf.countFrom)
{
// strict quantifier
return(curState);
}
WTState finalState = new WTState();;
for (int i = qtf.countFrom; i < Math.Min(qtf.countTo, length); i++)
{
WTState nextState = processNode(qtf.child, curState, length);
WTTransition _tran = new WTTransition();
_tran.node = null;
_tran.nextState = finalState;
if (qtf.greedy)
{
curState.transitions.Add(_tran);
}
else
{
curState.transitions.Insert(0, _tran);
}
curState = nextState;
}
WTTransition tran = new WTTransition();
tran.node = null;
tran.nextState = finalState;
curState.transitions.Add(tran);
return(finalState);
}
else if (node is WTReGroup)
{
WTReGroup grp = (WTReGroup)node;
WTState curState = state;
for (int i = 0; i < grp.children.Count; i++)
{
curState = processNode(grp.children[i], curState, length);
}
if (!grp.capturing && grp.children.Count == 1 && (grp.children[0] is WTReLiteral))
{
WTTransition tran = new WTTransition();
tran.node = null;
tran.bypassNode = (WTReLiteral)grp.children[0];
tran.nextState = curState;
state.transitions.Add(tran);
}
return(curState);
}
else if (node is WTReAlteration)
{
WTReAlteration alt = (WTReAlteration)node;
WTState finalState = new WTState();
for (int i = 0; i < alt.children.Count; i++)
{
WTState curState = processNode(alt.children[i], state, length);
WTTransition tran = new WTTransition();
tran.node = null;
tran.nextState = finalState;
curState.transitions.Add(tran);
}
return(finalState);
}
else
{
return(null);
}
}
WTReGroup parseSubpattern(string pattern, NSRange range, bool enclosed)
{
List <WTReNode> nodes = new List <WTReNode>(range.length);
List <WTReNode> alternations = null;
int startPos = 0, endPos = range.length;
bool escape = false;
WTReNode lastnode = null;
for (int i = 0; i < range.length; i++)
{
if (_finished)
{
throw new Exception("Found pattern end in the middle of string");
}
char c = pattern[range.location + i];
if (enclosed && i == 0 && c == '?')
{
// group modifiers are present
if (range.length < 3)
{
throw new Exception("Invalid group found in pattern");
}
char d = pattern[range.location + i + 1];
if (d == '<')
{
// tagged group (?<style1>…)
for (int j = i + 2; j < range.length; j++)
{
d = pattern[range.location + j];
;
if (d == '<')
{
throw new Exception("Invalid group tag found in pattern");
}
else if (d == '>')
{
if (j == i + 2)
{
throw new Exception("Empty group tag found in pattern");
}
i = j;
break;
}
else if (char.IsLetterOrDigit(d))
{
throw new Exception("Group tag contains invalid chars");
}
}
}
else if (d == '\'')
{
// tagged group (?'style2'…)
for (int j = i + 2; j < range.length; j++)
{
d = pattern[range.location + j];
if (d == '\'')
{
if (j == i + 2)
{
throw new Exception("Empty group tag found in pattern");
}
i = j;
break;
}
else if (!char.IsLetterOrDigit(d))
{
throw new Exception("Group tag contains invalid chars");
}
}
}
else if (d == ':')
{
// non-capturing group
enclosed = false;
i++;
}
else
{
throw new Exception("Unknown group modifier");
}
continue;
}
if (c == '\\' && !escape)
{
escape = true;
continue;
}
if (escape)
{
if (!isValidEscapedChar(c, false) || i == 0)
{
throw new Exception("Invalid escape sequence");
}
lastnode = this.parseCharset(pattern, new NSRange(range.location + i - 1, 2), false);
nodes.Add(lastnode);
escape = false;
}
else if (c == '(')
{
int brackets = 1;
bool escape2 = true;
for (int j = i + 1; j < range.length; j++)
{
char d = pattern[range.location + j];
if (escape2)
{
escape2 = false;
}
else if (d == '\\')
{
escape2 = true;
}
else if (d == '(')
{
brackets++;
}
else if (d == ')')
{
brackets--;
if (brackets == 0)
{
lastnode = this.parseSubpattern(pattern, new NSRange(range.location + i + 1, j - i - 1), true);
nodes.Add(lastnode);
i = j;
break;
}
}
}
if (brackets != 0)
{
throw new Exception("Unclosed group bracket");
}
}
else if (c == ')')
{
throw new Exception("Unopened group bracket");
}
else if (c == '[')
{
bool escape2 = false;
bool valid = false;
for (int j = i + 1; j < range.length; j++)
{
char d = pattern[range.location + j];
if (escape2)
{
escape2 = false;
}
else if (d == '\\')
{
escape2 = true;
}
else if (d == '[' || d == '(' || d == ')')
{
// invalid character
break;
}
else if (d == ']')
{
lastnode = this.parseCharset(pattern, new NSRange(range.location + i + 1, j - i - 1), true);
nodes.Add(lastnode);
i = j;
valid = true;
break;
}
}
if (!valid)
{
throw new Exception("Unclosed character set bracket");
}
}
else if (c == ']')
{
throw new Exception("Unopened character set bracket");
}
else if (c == '{')
{
if (lastnode == null || lastnode is WTReQuantifier)
{
throw new Exception("Invalid quantifier usage");
}
bool valid = false;
for (int j = i + 1; j < range.length; j++)
{
char d = pattern[range.location + j];
if (d == '}')
{
string from, to;
string str = pattern.Substring(range.location + i, j + 1 - i);
Match m = _exactQuantifierRegex.Match(str);
if (m.Success)
{
from = m.Groups[1].Value;
to = from;
}
else
{
m = _rangeQuantifierRegex.Match(str);
if (!m.Success)
{
throw new Exception("Invalid quantifier format");
}
else
{
from = m.Groups[1].Value;
to = m.Groups[2].Value;
}
}
WTReQuantifier qtf = new WTReQuantifier();
if (from == null || from.Equals(""))
{
qtf.countFrom = 0;
}
else
{
qtf.countFrom = int.Parse(from);
}
if (to == null || to.Equals(""))
{
qtf.countTo = int.MaxValue;
}
else
{
qtf.countTo = int.Parse(to);
}
if (qtf.countFrom > qtf.countTo)
{
throw new Exception("Invalid quantifier range");
}
nodes.RemoveAt(nodes.Count - 1); //removeLastObject
qtf.child = lastnode;
lastnode.parent = qtf;
lastnode = qtf;
nodes.Add(lastnode);
i = j;
valid = true;
break;
}
}
if (!valid)
{
throw new Exception("Unclosed quantifier bracket");
}
}
else if (c == '}')
{
throw new Exception("Unopened qualifier bracket");
}
else if (c == '*')
{
if (lastnode == null || lastnode is WTReQuantifier)
{
throw new Exception("Invalid quantifier usage");
}
nodes.RemoveAt(nodes.Count - 1);
WTReQuantifier qtf = new WTReQuantifier(0, int.MaxValue);
qtf.child = lastnode;
lastnode.parent = qtf;
lastnode = qtf;
nodes.Add(lastnode);
}
else if (c == '+')
{
if (lastnode == null || lastnode is WTReQuantifier)
{
throw new Exception("Invalid quantifier usage");
}
nodes.RemoveAt(nodes.Count - 1);
WTReQuantifier qtf = new WTReQuantifier(1, int.MaxValue);
qtf.child = lastnode;
lastnode.parent = qtf;
lastnode = qtf;
nodes.Add(lastnode);
}
else if (c == '?')
{
if (lastnode == null)
{
throw new Exception("Invalid quantifier usage");
}
if (lastnode is WTReQuantifier)
{
((WTReQuantifier)lastnode).greedy = false;
}
else
{
nodes.RemoveAt(nodes.Count - 1);
WTReQuantifier qtf = new WTReQuantifier(0, 1);
qtf.child = lastnode;
lastnode.parent = qtf;
lastnode = qtf;
nodes.Add(lastnode);
}
lastnode = null;
}
else if (c == '.')
{
// any character
lastnode = new WTReAnyCharacter();
nodes.Add(lastnode);
}
else if (c == '|')
{
// alternation
if (alternations == null)
{
alternations = new List <WTReNode>(2);
}
WTReGroup gr = groupFromNodes(nodes, enclosed);
gr.sourceRange = new NSRange(range.location + startPos, i - startPos);
startPos = i + 1;
alternations.Add(gr);
nodes.Clear();
lastnode = null;
}
else if (c == '$')
{
if (alternations != null && enclosed)
{
throw new Exception("End of string shouldn't be inside alternation");
}
if (range.location + i + 1 < pattern.Length)
{
throw new Exception("Unexpected end of string");
}
lastnode = new WTReEndOfString();
nodes.Add(lastnode);
endPos = i + 1;
_finished = true;
break;
}
else
{
lastnode = this.parseCharset(pattern, new NSRange(range.location + i, 1), false);
nodes.Add(lastnode);
}
}
if (escape)
{
throw new Exception("Invalid group ending");
}
WTReGroup g = groupFromNodes(nodes, enclosed);
g.sourceRange = new NSRange(range.location + startPos, endPos - startPos);
g.capturing = enclosed;
if (alternations != null)
{
// build alternation and enclose it into group
alternations.Add(g);
WTReAlteration a = new WTReAlteration();
a.children = alternations;
a.sourceRange = new NSRange(range.location, endPos);
// setup links
WTReNode prev = alternations[0];
prev.parent = a;
for (int i = 1; i < alternations.Count; i++)
{
WTReNode curr = alternations[i];
curr.parent = a;
prev.nextSibling = curr;
prev = curr;
}
g = new WTReGroup();
g.children = new List <WTReNode>();
g.children.Add(a);
g.capturing = enclosed;
g.sourceRange = a.sourceRange;
a.parent = g;
}
return(g);
}
