private static String Start(StringSource source, Char current, StringBuilder buffer)
{
if (current == Symbols.Minus)
{
current = source.Next();
if (current.IsNameStart() || source.IsValidEscape())
{
buffer.Append(Symbols.Minus);
return(Rest(source, current, buffer));
}
source.Back();
}
else if (current.IsNameStart())
{
buffer.Append(current);
return(Rest(source, source.Next(), buffer));
}
else if (current == Symbols.ReverseSolidus && source.IsValidEscape())
{
buffer.Append(source.ConsumeEscape());
return(Rest(source, source.Next(), buffer));
}
buffer.ToPool();
return(null);
}
private static Unit NumberExponential(StringSource source, StringBuilder buffer)
{
var letter = source.Current;
var current = source.Next();
if (current.IsDigit())
{
buffer.Append(letter).Append(current);
return(SciNotation(source, buffer));
}
else if (current == Symbols.Plus || current == Symbols.Minus)
{
var op = current;
current = source.Next();
if (current.IsDigit())
{
buffer.Append(letter).Append(op).Append(current);
return(SciNotation(source, buffer));
}
source.Back();
}
var number = buffer.ToString();
return(Dimension(source, number, buffer.Clear().Append(letter)));
}
internal static IEnumerable <IfHeaderCondition> Parse([NotNull] StringSource source, [NotNull] EntityTagComparer entityTagComparer)
{
while (!source.SkipWhiteSpace())
{
var isNot = false;
EntityTag?etag = null;
if (source.AdvanceIf("Not", StringComparison.OrdinalIgnoreCase))
{
isNot = true;
source.SkipWhiteSpace();
}
Uri stateToken;
if (CodedUrlParser.TryParse(source, out stateToken))
{
// Coded-URL found
}
else if (source.Get() == '[')
{
// Entity-tag found
etag = EntityTag.Parse(source).Single();
if (!source.AdvanceIf("]"))
{
throw new ArgumentException($"{source.Remaining} is not a valid condition (ETag not ending with ']')", nameof(source));
}
}
else
{
source.Back();
break;
}
yield return(new IfHeaderCondition(isNot, stateToken, etag, entityTagComparer));
}
}
private static UrlReference DoubleQuoted(StringSource source)
{
var buffer = StringBuilderPool.Obtain();
while (true)
{
var current = source.Next();
if (current.IsLineBreak())
{
return(Bad(source, buffer));
}
else if (Symbols.EndOfFile == current)
{
return(new UrlReference(buffer.ToPool()));
}
else if (current == Symbols.DoubleQuote)
{
return(End(source, buffer));
}
else if (current != Symbols.ReverseSolidus)
{
buffer.Append(current);
}
else
{
current = source.Next();
if (current == Symbols.EndOfFile)
{
source.Back();
return(new UrlReference(buffer.ToPool()));
}
else if (current.IsLineBreak())
{
buffer.AppendLine();
}
else
{
source.Back();
buffer.Append(source.ConsumeEscape());
}
}
}
}
public static Char BackTo(this StringSource source, Int32 index)
{
var diff = source.Index - index;
var current = Symbols.Null;
while (diff > 0)
{
current = source.Back();
diff--;
}
return(current);
}
private static Unit NumberDash(StringSource source, StringBuilder buffer)
{
var current = source.Next();
if (current.IsNameStart() || source.IsValidEscape())
{
var number = buffer.ToString();
return(Dimension(source, number, buffer.Clear().Append(Symbols.Minus)));
}
else
{
source.Back();
return(new Unit(buffer.ToPool(), String.Empty));
}
}
private static String SingleQuoted(StringSource source)
{
var buffer = StringBuilderPool.Obtain();
while (true)
{
var current = source.Next();
switch (current)
{
case Symbols.SingleQuote:
case Symbols.EndOfFile:
source.Next();
return(buffer.ToPool());
case Symbols.FormFeed:
case Symbols.LineFeed:
buffer.ToPool();
return(null);
case Symbols.ReverseSolidus:
current = source.Next();
if (current.IsLineBreak())
{
buffer.AppendLine();
}
else if (current != Symbols.EndOfFile)
{
source.Back();
buffer.Append(source.ConsumeEscape());
}
else
{
return(buffer.ToPool());
}
break;
default:
buffer.Append(current);
break;
}
}
}
/// <summary>
/// Consumes the escape sequence if any. Assumes, the source currently being at a
/// solidus (valid escape).
/// </summary>
public static String ConsumeEscape(this StringSource source)
{
var current = source.Next();
if (current.IsHex())
{
var isHex = true;
var escape = new Char[6];
var length = 0;
while (isHex && length < escape.Length)
{
escape[length++] = current;
current = source.Next();
isHex = current.IsHex();
}
if (!current.IsSpaceCharacter())
{
source.Back();
}
var code = 0;
var pwr = 1;
for (var i = length - 1; i >= 0; i--)
{
code += escape[i].FromHex() * pwr;
pwr *= 16;
}
if (!code.IsInvalid())
{
return(Char.ConvertFromUtf32(code));
}
current = Symbols.Replacement;
}
return(current.ToString());
}
/// <summary>
/// 4.4.1. Data state
/// </summary>
private CssSelectorToken Data(Char current)
{
switch (current)
{
case Symbols.FormFeed:
case Symbols.LineFeed:
case Symbols.CarriageReturn:
case Symbols.Tab:
case Symbols.Space:
_source.SkipSpaces();
return(new CssSelectorToken(CssTokenType.Whitespace, " "));
case Symbols.Num:
return(HashStart());
case Symbols.Dot:
current = _source.Next();
if (current.IsDigit())
{
return(NumberStart(_source.Back()));
}
else
{
var token = Data(current);
if (token.Type == CssTokenType.Ident)
{
return(new CssSelectorToken(CssTokenType.Class, token.Data));
}
}
return(NewInvalid());
case Symbols.Asterisk:
current = _source.Next();
if (current == Symbols.Equality)
{
_source.Next();
return(NewMatch(CombinatorSymbols.InText));
}
return(NewDelimiter(Symbols.Asterisk));
case Symbols.Comma:
_source.Next();
return(new CssSelectorToken(CssTokenType.Comma, ","));
case Symbols.GreaterThan:
current = _source.Next();
if (current == Symbols.GreaterThan)
{
current = _source.Next();
if (current == Symbols.GreaterThan)
{
_source.Next();
return(new CssSelectorToken(CssTokenType.Deep, ">>>"));
}
return(new CssSelectorToken(CssTokenType.Descendent, ">>"));
}
return(NewDelimiter(Symbols.GreaterThan));
case Symbols.Minus:
{
var c1 = _source.Next();
if (c1 != Symbols.EndOfFile)
{
var c2 = _source.Next();
_source.Back(2);
if (c1.IsDigit() || (c1 == Symbols.Dot && c2.IsDigit()))
{
return(NumberStart(current));
}
else if (c1.IsNameStart())
{
return(IdentStart(current));
}
else if (c1 == Symbols.ReverseSolidus && !c2.IsLineBreak() && c2 != Symbols.EndOfFile)
{
return(IdentStart(current));
}
else if (c1 == Symbols.Minus && c2 == Symbols.GreaterThan)
{
_source.Next(2);
return(NewInvalid());
}
_source.Next();
}
return(NewDelimiter(Symbols.Minus));
}
case Symbols.Plus:
{
var c1 = _source.Next();
if (c1 != Symbols.EndOfFile)
{
var c2 = _source.Next();
_source.Back();
if (c1.IsDigit() || (c1 == Symbols.Dot && c2.IsDigit()))
{
_source.Back();
return(NumberStart(current));
}
}
return(NewDelimiter(Symbols.Plus));
}
case Symbols.Colon:
_source.Next();
return(new CssSelectorToken(CssTokenType.Colon, ":"));
case '0':
case '1':
case '2':
case '3':
case '4':
case '5':
case '6':
case '7':
case '8':
case '9':
return(NumberStart(current));
case Symbols.DoubleQuote:
return(StringDQ());
case Symbols.SingleQuote:
return(StringSQ());
case 'U':
case 'u':
current = _source.Next();
if (current == Symbols.Plus)
{
current = _source.Next();
if (current.IsHex() || current == Symbols.QuestionMark)
{
return(UnicodeRange(current));
}
current = _source.Back();
}
return(IdentStart(_source.Back()));
case Symbols.SquareBracketOpen:
_source.Next();
return(new CssSelectorToken(CssTokenType.SquareBracketOpen, "["));
case Symbols.SquareBracketClose:
_source.Next();
return(new CssSelectorToken(CssTokenType.SquareBracketClose, "]"));
case Symbols.RoundBracketClose:
_source.Next();
return(new CssSelectorToken(CssTokenType.RoundBracketClose, ")"));
case Symbols.Solidus:
current = _source.Next();
if (current == Symbols.Asterisk)
{
return(Data(_source.SkipCssComment()));
}
return(NewDelimiter(Symbols.Solidus));
case Symbols.ReverseSolidus:
current = _source.Next();
if (current.IsLineBreak() || current == Symbols.EndOfFile)
{
return(NewDelimiter(Symbols.ReverseSolidus));
}
return(IdentStart(_source.Back()));
case Symbols.LessThan:
current = _source.Next();
if (current == Symbols.ExclamationMark)
{
current = _source.Next();
if (current == Symbols.Minus)
{
current = _source.Next();
if (current == Symbols.Minus)
{
_source.Next();
return(NewInvalid());
}
current = _source.Back();
}
current = _source.Back();
}
return(NewDelimiter(Symbols.LessThan));
case Symbols.Accent:
current = _source.Next();
if (current == Symbols.Equality)
{
_source.Next();
return(NewMatch(CombinatorSymbols.Begins));
}
return(NewDelimiter(Symbols.Accent));
case Symbols.EndOfFile:
return(new CssSelectorToken(CssTokenType.EndOfFile, String.Empty));
case Symbols.Pipe:
current = _source.Next();
if (current == Symbols.Equality)
{
_source.Next();
return(NewMatch(CombinatorSymbols.InToken));
}
else if (current == Symbols.Pipe)
{
_source.Next();
return(new CssSelectorToken(CssTokenType.Column, CombinatorSymbols.Column));
}
return(NewDelimiter(Symbols.Pipe));
case Symbols.Dollar:
current = _source.Next();
if (current == Symbols.Equality)
{
_source.Next();
return(NewMatch(CombinatorSymbols.Ends));
}
return(NewDelimiter(Symbols.Dollar));
case Symbols.Tilde:
current = _source.Next();
if (current == Symbols.Equality)
{
_source.Next();
return(NewMatch(CombinatorSymbols.InList));
}
return(NewDelimiter(Symbols.Tilde));
case Symbols.ExclamationMark:
current = _source.Next();
if (current == Symbols.Equality)
{
_source.Next();
return(NewMatch(CombinatorSymbols.Unlike));
}
return(NewDelimiter(Symbols.ExclamationMark));
case Symbols.At:
return(AtKeywordStart());
case Symbols.RoundBracketOpen:
case Symbols.CurlyBracketOpen:
case Symbols.CurlyBracketClose:
case Symbols.Semicolon:
_source.Next();
return(NewInvalid());
default:
if (current.IsNameStart())
{
return(IdentStart(current));
}
_source.Next();
return(NewDelimiter(current));
}
}
