protected override void Search(ref NativeMethods.SearchParams searchParams)
{
var start = searchParams.TextStart;
if (searchParams.MatchStart != IntPtr.Zero)
{
start = searchParams.MatchStart + searchParams.MatchLength * sizeof(char);
}
var end = searchParams.TextStart + searchParams.TextLength * sizeof(char);
var count = Pointers.Offset64(start, end) / sizeof(char);
var searchHitPtr = NativeMethods.Utf16_Search(
start,
count,
_patternPtr.Pointer,
_patternLength,
_searchOptions);
if (searchHitPtr == IntPtr.Zero)
{
searchParams.MatchStart = IntPtr.Zero;
searchParams.MatchLength = 0;
}
else
{
searchParams.MatchStart = searchHitPtr;
searchParams.MatchLength = _patternLength;
}
}
/// <summary>
/// Return a new fragment starting at <paramref name="startPtr"/>
/// and containing <paramref name="count"/> characters.
/// </summary>
public TextFragment Sub(IntPtr startPtr, int count)
{
var byteOffset = Pointers.Offset32(_textPtr, startPtr);
if (byteOffset < 0 || (byteOffset % _characterSize) != 0)
{
ThrowArgumentException();
}
return(Sub(byteOffset / _characterSize, count));
}
/// <summary>
/// Find all occurrences of the pattern in the text block starting at
/// |<paramref name="textPtr"/>| and containing |<paramref name="textLen"/>|
/// characters.
/// </summary>
public IEnumerable <FilePositionSpan> SearchAll(IntPtr textPtr, int textLen)
{
var currentPtr = textPtr;
var remainingLength = textLen;
while (true)
{
currentPtr = Search(currentPtr, remainingLength);
if (currentPtr == IntPtr.Zero)
{
break;
}
// TODO(rpaquay): We are limited to 2GB for now.
var offset = Pointers.Offset32(textPtr, currentPtr);
yield return(new FilePositionSpan {
Position = offset, Length = PatternLength
});
currentPtr += PatternLength;
remainingLength = textLen - offset - PatternLength;
}
}
