* Fixed a swapping bug for 16 bit colorspaces

* Added some comments
* Added some checking to avoid noop shifts
* Added buffer length checks
* Implemented (as Stephan suggested) a version of ConvertBits() that takes offsets.
This new version allows to move a region of the source into a region (possibly not at the same point) on the dest while converting colorspaces on the fly.

git-svn-id: file:///srv/svn/repos/haiku/haiku/trunk@16592 a95241bf-73f2-0310-859d-f6bbb57e9c96

src/kits/interface/Bitmap.cpp

@@ -519,8 +519,9 @@ BBitmap::ImportBits(const void *data, int32 length, int32 bpr, int32 offset,
 	if (bpr < 0)
 		bpr = get_bytes_per_row(colorSpace, width);
 
-	return BPrivate::ConvertBits(data, fBasePtr, bpr, fBytesPerRow,
-		colorSpace, fColorSpace, width, fBounds.IntegerHeight() + 1);
+	return BPrivate::ConvertBits(data, fBasePtr, length, fSize, bpr,
+		fBytesPerRow, colorSpace, fColorSpace, width,
+		fBounds.IntegerHeight() + 1);
 }
 
 // ImportBits