private static string ParseGroupName(RevgexStringReader inp)
{
inp.Read(); // ':'
var buf = "";
while (true)
{
switch (inp.Peek())
{
case -1: throw Error(inp, "Incomplete group name specification.");
case ';':
if (buf.Length == 0)
{
throw Error(inp, "Empty group name specification.");
}
inp.Read();
return(buf);
default:
buf += inp.Read();
continue;
}
}
}
private static RTree[] ParseGroupBody(RevgexStringReader inp, GroupSet groups)
{
var alternatives = new List <List <RTree> > {
new List <RTree>()
};
while (true)
{
switch (inp.Peek())
{
case -1:
throw Error(inp, "Missing ')'.");
case '|':
inp.Read();
alternatives.Add(new List <RTree>());
break;
case ')':
inp.Read();
return(alternatives.Count == 1
? alternatives[0].ToArray()
: new RTree[] { new RAlternation(alternatives.Select(a => new RGroup(a.ToArray())).ToArray()) });
default:
alternatives[alternatives.Count - 1].Add(ParseSingleSubtree(inp, groups));
break;
}
}
}
private static RModifier.ModifierType ParseModifierType(RevgexStringReader inp)
{
if (inp.Peek() < 0)
{
throw Error(inp, "Missing modifier type.");
}
switch (inp.Read())
{
case 'U': return(RModifier.ModifierType.ToUpper);
case 'l': return(RModifier.ModifierType.ToLower);
case 'C': return(RModifier.ModifierType.Capitalize);
case '_': return(RModifier.ModifierType.ToUnderscores);
case '-': return(RModifier.ModifierType.ToDashes);
case ' ': return(RModifier.ModifierType.ToSpaces);
case 'n':
case 'N': return(RModifier.ModifierType.RemoveSpaces);
case 't':
case 'T': return(RModifier.ModifierType.TrimWhitespace);
case '0': return(RModifier.ModifierType.RemoveLeadingZeros);
case '!': return(RModifier.ModifierType.Ignore);
default: throw Error(inp, "Invalid modifier type.");
}
}
private static RTree ParseStdGroup(RevgexStringReader inp, GroupSet groups)
{
string name = null;
var id = -1;
if (inp.Peek() == ':')
{
name = ParseGroupName(inp);
}
if (name != null)
{
if (!groups.Add(name))
{
throw Error(inp, $"Group name {name} is already used.");
}
}
else
{
groups.Add(id = groups.GetNextId());
}
var body = ParseGroupBody(inp, groups);
if (name != null)
{
groups.Specify(name, new RGroup(body));
return(new RNamedGroupRef(name, LookupQuantifier(inp)));
}
else
{
groups.Specify(id, new RGroup(body));
return(new RGroupRef(id, LookupQuantifier(inp)));
}
}
private static RTree ParseDelimitedSequence(RevgexStringReader inp, GroupSet groups)
{
var type = inp.Read(); // '"' or '
var delimiter = "";
while (true)
{
if (inp.Peek() == -1)
{
throw Error(inp, "Incomplete delimiter specification.");
}
else if (inp.Peek() == ';')
{
inp.Read();
break;
}
else if (inp.Peek() == '\\')
{
inp.Read();
if (inp.Peek() < 0)
{
throw Error(inp, "Incomplete delimiter specification.");
}
delimiter += inp.Read();
}
else
{
delimiter += inp.Read();
}
}
var quantifier = LookupQuantifier(inp);
var body = ParseGroupBody(inp, groups);
return(new RDelimitedSequence(quantifier, delimiter, type == '\'', body));
}
private static bool TryParseSimpleEscapeSequence(RevgexStringReader inp, out char c)
{
inp.Read(); // '\'
switch (inp.Peek())
{
case 'n':
inp.Read();
c = '\n';
return(true);
case 't':
inp.Read();
c = '\t';
return(true);
default:
if (inp.Peek() > 0 && "\\[](){}+*?$. \n\t".Contains((char)inp.Peek()))
{
c = inp.Read();
return(true);
}
inp.Unread(); // '\'
c = '\0';
return(false);
}
}
private static RTree ParseModifier(RevgexStringReader inp, GroupSet groups)
{
inp.Read(); // '!'
var type = ParseModifierType(inp);
var body = ParseGroupBody(inp, groups);
return(new RModifier(type, body));
}
private static RTree ParseValueReference(RevgexStringReader inp, GroupSet groups)
{
inp.Read(); // '$'
var c = inp.Peek();
if (c >= '0' && c <= '9')
{
var groupId = inp.Read() - '0';
c = inp.Peek();
if (c >= '0' && c <= '9')
{
groupId = groupId * 10 + (inp.Read() - '0');
}
if (groupId == 0)
{
throw Error(inp, "Value backreference to the entire patternt (zero-th group) is not allowed.");
}
if (groups.Get(groupId) == null)
{
throw Error(inp, "Invalid group backreference.");
}
return(new RGroupValueRef(groupId, LookupQuantifier(inp)));
}
switch (c)
{
case -1:
throw Error(inp, "Incomplete group value backreference.");
case ':':
var groupName = ParseGroupName(inp);
if (groups.Get(groupName) == null)
{
throw Error(inp, "Invalid named group value backreference.");
}
return(new RNamedGroupValueRef(groupName, LookupQuantifier(inp)));
case '(':
inp.Read();
var groupId = 0;
c = inp.Peek();
do
{
if (c < '0' || c > '9')
{
throw Error(inp, "Invalid group value backreference.");
}
groupId = groupId * 10 + (inp.Read() - '0');
} while ((c = inp.Peek()) != ')');
inp.Read(); // ')'
if (groups.Get(groupId) == null)
{
throw Error(inp, "Invalid group value backreference.");
}
return(new RGroupValueRef(groupId, LookupQuantifier(inp)));
default: throw Error(inp, "Invalid group value backreference.");
}
}
private static RTree ParseControlGroup(RevgexStringReader inp, GroupSet groups)
{
inp.Read(); // '?'
switch (inp.Peek())
{
case -1:
throw Error(inp, "Incomplete control group.");
case ':':
// non-capturing group
inp.Read();
return(new RGroup(ParseGroupBody(inp, groups)));
default:
throw Error(inp, "Invalid control group.");
}
}
private static GroupSet Parse(RevgexStringReader inp, bool allowPredefinedGroups)
{
var groups = new GroupSet();
if (allowPredefinedGroups)
{
groups.Add(":maleName", PredefinedGroups.MaleName);
groups.Add(":femaleName", PredefinedGroups.FemaleName);
groups.Add(":surname", PredefinedGroups.Surname);
groups.Add(":byte", PredefinedGroups.Byte);
groups.Add(":int", PredefinedGroups.Int);
groups.Add(":uint", PredefinedGroups.UnsignedInt);
groups.Add(":usPhone", PredefinedGroups.USPhone);
groups.Add(":mailSuffix", PredefinedGroups.MailSuffix);
groups.Add(":passwd", PredefinedGroups.Password);
}
groups.Add(0);
var alternatives = new List <List <RTree> > {
new List <RTree>()
};
while (inp.Peek() >= 0)
{
if (inp.Peek() == '|')
{
inp.Read();
alternatives.Add(new List <RTree>());
}
else
{
alternatives[alternatives.Count - 1].Add(ParseSingleSubtree(inp, groups));
}
}
groups.Specify(0,
alternatives.Count == 1
? new RGroup(alternatives[0].ToArray())
: new RGroup(new RAlternation(alternatives.Select(a => new RGroup(a.ToArray())).ToArray())));
return(groups);
}
private static RTree ParseAnyGroup(RevgexStringReader inp, GroupSet groups)
{
inp.Read(); // '('
switch (inp.Peek())
{
case -1:
throw Error(inp, "Missing ')'.");
case '!':
return(ParseModifier(inp, groups));
case '?':
return(ParseControlGroup(inp, groups));
case '\'':
case '"':
return(ParseDelimitedSequence(inp, groups));
default:
return(ParseStdGroup(inp, groups));
}
}
private static FormatException Error(RevgexStringReader inp, string message)
{
return(new FormatException($"Error around line {inp.Line}, column {inp.Column}: \n{message}"));
}
private static IQuantifier LookupQuantifier(RevgexStringReader inp)
{
switch (inp.Peek())
{
case '+':
inp.Read();
if (inp.Peek() == '?')
{
inp.Read();
return(QuantifierPlusLazy.Instance);
}
return(QuantifierPlus.Instance);
case '*':
inp.Read();
if (inp.Peek() == '?')
{
inp.Read();
return(QuantifierAsteriskLazy.Instance);
}
return(QuantifierAsterisk.Instance);
case '?':
inp.Read();
return(QuantifierOptional.Instance);
case '{':
inp.Read();
int buf = 0, min = -1;
var numberSpecified = false;
while (true)
{
var c = inp.Peek();
if (c < 0)
{
throw Error(inp, "Incomplete quantifier (missing '}').");
}
inp.Read();
if (c >= '0' && c <= '9')
{
buf = buf * 10 + (c - '0');
numberSpecified = true;
}
else if (c == ',')
{
if (numberSpecified)
{
min = buf;
buf = 0;
numberSpecified = false;
}
else
{
throw Error(inp, "Incomplete quantifier (missing number before ',').");
}
}
else if (c == '}')
{
if (numberSpecified)
{
if (min < 0 || min == buf)
{
return(new QuantifierFixed(buf));
}
if (buf < min)
{
throw Error(inp, "Invalid quantifier (max < min).");
}
return(new QuantifierRange(min, buf));
}
if (min < 0)
{
throw Error(inp, "Empty quantifier.");
}
return(new QuantifierMin(min));
}
}
default: return(QuantifierOne.Instance);
}
}
private static RTree ParseSingleSubtree(RevgexStringReader inp, GroupSet groups)
{
var buffer = "";
while (true)
{
switch (inp.Peek())
{
case -1:
return(buffer.Length > 0
? new RFixedString(buffer, QuantifierOne.Instance)
: REmpty.Instance);
case '(':
return(buffer.Length > 0
? new RFixedString(buffer, QuantifierOne.Instance)
: ParseAnyGroup(inp, groups));
case ')':
return(buffer.Length > 0
? new RFixedString(buffer, QuantifierOne.Instance)
: throw Error(inp, "Unexpected right parenthesis."));
case '*':
case '+':
case '{':
case '?':
if (buffer.Length > 0)
{
if (buffer.Length == 1)
{
return(new RFixedString(buffer, LookupQuantifier(inp)));
}
inp.UnreadEscaped();
return(new RFixedString(buffer.Substring(0, buffer.Length - 1), LookupQuantifier(inp)));
}
throw Error(inp, $"Unexpected character {inp.Peek()}.");
case '\\':
if (TryParseSimpleEscapeSequence(inp, out var ch))
{
buffer += ch;
continue;
}
return(buffer.Length > 0
? new RFixedString(buffer, QuantifierOne.Instance)
: ParseEscapeSequence(inp, groups));
case '$':
return(buffer.Length > 0
? new RFixedString(buffer, QuantifierOne.Instance)
: ParseValueReference(inp, groups));
case '.':
if (buffer.Length > 0)
{
return(new RFixedString(buffer, QuantifierOne.Instance));
}
else
{
inp.Read();
return(RChar.Dot(LookupQuantifier(inp)));
}
case '[':
return(buffer.Length > 0
? new RFixedString(buffer, QuantifierOne.Instance)
: ParseCharSet(inp));
case '|':
return(buffer.Length > 0
? new RFixedString(buffer, QuantifierOne.Instance)
: REmpty.Instance);
default:
buffer += inp.Read();
continue;
}
}
}
private static RTree ParseCharSet(RevgexStringReader inp)
{
inp.Read(); // '['
var set = new HashSet <char>();
var first = true;
var inverse = false;
var prevWasSpecial = true;
var prev = '\0';
while (true)
{
if (inp.Peek() < 0)
{
throw Error(inp, "Incomplete char set specification.");
}
var current = inp.Read();
switch (current)
{
case '^':
if (first)
{
inverse = true;
prevWasSpecial = true;
}
else
{
set.Add('^');
prevWasSpecial = false;
}
break;
case '-':
if (prevWasSpecial || inp.Peek() == ']')
{
set.Add('-');
}
else
{
var j = prev;
if (inp.Peek() < 0)
{
throw Error(inp, "Incomplete char set specification.");
}
var end = inp.Read();
if (end == '\\')
{
if (inp.Peek() < 0)
{
throw Error(inp, "Incomplete char set specification.");
}
end = inp.Read();
if ("wWdDsS".Contains(end))
{
throw new FormatException();
}
if (end == 'n')
{
end = '\n';
}
else if (end == 't')
{
end = '\t';
}
}
for (++j; j <= end; ++j)
{
set.Add(j);
}
}
prevWasSpecial = false;
break;
case '\\':
if (inp.Peek() < 0)
{
throw Error(inp, "Incomplete char set specification.");
}
current = inp.Read();
switch (current)
{
case 'w':
foreach (var c in RChar._w)
{
set.Add(c);
}
prevWasSpecial = true;
break;
case 'W':
foreach (var c in RChar._W)
{
set.Add(c);
}
prevWasSpecial = true;
break;
case 's':
foreach (var c in RChar._s)
{
set.Add(c);
}
prevWasSpecial = true;
break;
case 'S':
foreach (var c in RChar._S)
{
set.Add(c);
}
prevWasSpecial = true;
break;
case 'd':
foreach (var c in RChar._d)
{
set.Add(c);
}
prevWasSpecial = true;
break;
case 'D':
foreach (var c in RChar._D)
{
set.Add(c);
}
prevWasSpecial = true;
break;
case 't':
set.Add('\t');
prevWasSpecial = false;
break;
case 'n':
set.Add('\n');
prevWasSpecial = false;
break;
default:
set.Add(current);
prevWasSpecial = false;
break;
}
break;
case ']':
return(inverse
? new RReversedChar(set.ToArray(), LookupQuantifier(inp))
: (RTree) new RChar(set.ToArray(), LookupQuantifier(inp)));
default:
set.Add(current);
prevWasSpecial = false;
break;
}
first = false;
prev = current;
}
}
private static RTree ParseEscapeSequence(RevgexStringReader inp, GroupSet groups)
{
inp.Read(); // '\'
var c = inp.Peek();
if (c >= '0' && c <= '9')
{
var groupId = inp.Read() - '0';
c = inp.Peek();
if (c >= '0' && c <= '9')
{
groupId = groupId * 10 + (inp.Read() - '0');
}
if (groupId == 0)
{
throw Error(inp, "Backreference to the entire patternt (zero-th group) is not allowed.");
}
if (groups.Get(groupId) == null)
{
throw Error(inp, "Invalid group backreference.");
}
return(new RGroupRef(groupId, LookupQuantifier(inp)));
}
switch (c)
{
case -1:
throw Error(inp, "Incomplete escape sequence.");
case ':':
var groupName = ParseGroupName(inp);
if (groups.Get(groupName) == null)
{
throw Error(inp, "Invalid named group backreference.");
}
return(new RNamedGroupRef(groupName, LookupQuantifier(inp)));
case '(':
inp.Read();
var groupId = 0;
c = inp.Peek();
do
{
if (c < '0' || c > '9')
{
throw Error(inp, "Invalid group backreference.");
}
groupId = groupId * 10 + (inp.Read() - '0');
} while ((c = inp.Peek()) != ')');
inp.Read(); // ')'
if (groups.Get(groupId) == null)
{
throw Error(inp, "Invalid group backreference.");
}
return(new RGroupRef(groupId, LookupQuantifier(inp)));
case 'w':
inp.Read();
return(RChar.w(LookupQuantifier(inp)));
case 'W':
inp.Read();
return(RChar.W(LookupQuantifier(inp)));
case 's':
inp.Read();
return(RChar.s(LookupQuantifier(inp)));
case 'S':
inp.Read();
return(RChar.S(LookupQuantifier(inp)));
case 'd':
inp.Read();
return(RChar.d(LookupQuantifier(inp)));
case 'D':
inp.Read();
return(RChar.D(LookupQuantifier(inp)));
default:
return(new RFixedString(inp.Read().ToString(), LookupQuantifier(inp)));
}
}