The UTF8 <==> UCS conversion utilities in scintilla/src/UniConversion.h
would be useful to the outside world. For example, in my application, I am
returning the selected text and searching using UCS encoded Windows BSTRs.
What would also be useful are character navigation functions:
int GetUTF8ByteCount( char ch ) // Source: wikipedia/UTF8
{
switch( ch & 0xF0 )
{
case 0x0: ... case 0x7: return 1;
case 0x8: ... case 0xB: return -1;
case 0xC: case 0xD: return 2;
case 0xE: return 3;
case 0xF: return 4;
}
}
Return the position of the first non-partial character by scanning forward
or backward, so that the index is not located mid-character:
int Normalize( int pos, bool forward )
{
if( GetUTF8ByteCount( GetCharAt( pos )) == -1 )
{
pos = forward ? CharNext( pos ) : CharPrev( pos );
}
return pos;
}
Return the next/previous non-partial character:
int CharNext( int pos )
{
while( GetUTF8ByteCount( GetCharAt( pos )) == -1 )
{
++pos;
}
return pos;
}
int CharPrev( int pos )
{
while( GetUTF8ByteCount( GetCharAt( pos )) == -1 )
{
--pos;
}
return pos;
}
This would help to allow users of the Scintilla library to write UCS
interfaces to the Scintilla control.
NOTE: The conversion algorithm doesn't handle the 4th UTF8 byte. I'm
assuming this is due to lack of support for UTF16 surrogate pairs and
Unicode planar characters in Windows.
- Reece
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