internal static bool CompareCurrentDecodedString(CharacterStream stream, string compareText, bool ignoreCase, out int matchLength)
{
#if SUPPORT_ENCODED_CSS
matchLength = 0;
if (AtEnd)
{
return(compareText.Length == 0);
}
if (_textProvider.Length - _index < compareText.Length)
{
return(false);
}
if (!TextHelpers.RangeCouldContainEncodedChars(_textProvider, _index, compareText.Length))
{
// No slashes, so no escapes, and a simple string comparison can be done
matchLength = compareText.Length;
return(CompareCurrentString(compareText, ignoreCase));
}
// There's a slash in there somewhere, so decode every character
// (this requires no memory allocations)
int startPosition = Position;
bool result = true;
for (int i = 0; i < compareText.Length; i++)
{
char compareChar = compareText[i];
DecodedChar decodedChar = DecodedCurrentChar;
if (ignoreCase
? (char.ToLowerInvariant(compareChar) == char.ToLowerInvariant(decodedChar.Char))
: (compareChar == decodedChar.Char))
{
// Matching so far...
Advance(decodedChar.EncodedLength);
}
else
{
result = false;
break;
}
}
matchLength = Position - startPosition;
Position = startPosition;
return(result);
#else
matchLength = string.IsNullOrEmpty(compareText) ? 0 : compareText.Length;
return(stream.TextProvider.CompareTo(stream.Position, compareText, ignoreCase));
#endif
}
/// <summary>
/// This is similar to string.Substring, but it deals with encoded unicode chars and escaped chars.
/// Escaped line breaks are only valid within strings, so set "forStringToken" to true for strings.
/// </summary>
public static string DecodeText(ITextProvider textProvider, int start, int length, bool forStringToken)
{
if (RangeCouldContainEncodedChars(textProvider, start, length))
{
// Need to carefully investigate every character and decode it
System.Text.StringBuilder sb = new System.Text.StringBuilder(length);
CharacterStream cs = new CharacterStream(textProvider);
for (cs.Position = start; cs.Position < start + length && !cs.IsAtEnd;)
{
if (forStringToken && AtEscapedNewLine(cs))
{
// Ignore this line break within a string
cs.Advance(1);
SkipNewLine(cs);
}
else
{
DecodedChar decodedChar = TextHelpers.DecodeCurrentChar(cs);
if (decodedChar.RequiresUtf32)
{
// http://www.w3.org/TR/CSS21/syndata.html#characters
//
// If the number is outside the range allowed by Unicode (e.g., "\110000" is above the maximum 10FFFF
// allowed in current Unicode), the UA may replace the escape with the "replacement character" (U+FFFD).
int utf32 = decodedChar.CharUtf32;
if ((utf32 < 0) || (utf32 > 0x10FFFF))
{
utf32 = 0xFFFD;
}
sb.Append(char.ConvertFromUtf32(utf32));
}
else
{
sb.Append(decodedChar.Char);
}
cs.Advance(decodedChar.EncodedLength);
}
}
return(sb.ToString());
}
else
{
// Nothing can possibly be encoded, so return the plain string
return(textProvider.GetText(start, length));
}
}
