/// <summary>
/// Prepare the unknown character for encoding
/// </summary>
/// <param name="unknownChar">character to process</param>
/// <param name="index">position in input string</param>
/// <returns>true if characters to process placed in buffer</returns>
public override bool Fallback(char charUnknown, int index)
{
// if we're not done with the current buffer, we're being recursive.
if (m_position < m_fallbackString.Length)
{
throw new ArgumentException(CssStringMgr.GetString(StringEnum.FallbackEncodingFailed));
}
// Go ahead and get our fallback
m_fallbackString = GetEncoding((int)charUnknown);
m_position = 0;
// return false if we have no string, indicating we didn't encode it
return(m_fallbackString.Length > 0);
}
/// <summary>
/// Prepare the unknwon surrogate pair for encoding
/// </summary>
/// <param name="unknownCharHigh">high surrogate pair character</param>
/// <param name="unknownCharLow">low surrogate pair character</param>
/// <param name="index">index of character in the stream</param>
/// <returns></returns>
public override bool Fallback(char charUnknownHigh, char charUnknownLow, int index)
{
// if we're not done with the current buffer, we're being recursive.
if (m_position < m_fallbackString.Length)
{
throw new ArgumentException(CssStringMgr.GetString(StringEnum.FallbackEncodingFailed));
}
// de-surrogate the pair into a single value in the range 0x010000 to 0x10ffff
int unicodeChar = 0x10000
+ ((int)charUnknownHigh - 0xD800) * 0x400
+ ((int)charUnknownLow - 0xDC00);
// validate the range?
// get the fallback string
m_fallbackString = GetEncoding(unicodeChar);
m_position = 0;
// return false if we have no string, indicating we didn't encode it
return(m_fallbackString.Length > 0);
}
