/// <summary>
/// Get text immediately preceding cpLimit.
/// </summary>
internal TextSpan <CultureSpecificCharacterBufferRange> GetPrecedingText(TextSource textSource, int cpLimit)
{
if (cpLimit > 0)
{
SpanRider textRunSpanRider = new SpanRider(_textRunVector, _latestPosition);
if (textRunSpanRider.At(cpLimit - 1))
{
CharacterBufferRange charString = CharacterBufferRange.Empty;
CultureInfo culture = null;
TextRun run = textRunSpanRider.CurrentElement as TextRun;
if (run != null)
{
// Only TextRun containing text would have non-empty Character buffer range.
if (TextRunInfo.GetRunType(run) == Plsrun.Text &&
run.CharacterBufferReference.CharacterBuffer != null)
{
charString = new CharacterBufferRange(
run.CharacterBufferReference,
cpLimit - textRunSpanRider.CurrentSpanStart);
culture = CultureMapper.GetSpecificCulture(run.Properties.CultureInfo);
}
return(new TextSpan <CultureSpecificCharacterBufferRange>(
cpLimit - textRunSpanRider.CurrentSpanStart, // cp length
new CultureSpecificCharacterBufferRange(culture, charString)
));
}
}
}
// not in cache so call back to client
return(textSource.GetPrecedingText(cpLimit));
}