Added missing method [isValidGlyphIndex:].

git-svn-id: svn+ssh://svn.gna.org/svn/gnustep/libs/gui/trunk@17749 72102866-910b-0410-8b05-ffd578937521

Headers/Additions/GNUstepGUI/GSLayoutManager.h

@@ -186,6 +186,9 @@ to NO. */
 - (NSGlyph) glyphAtIndex: (unsigned int)glyphIndex
 	isValidIndex: (BOOL *)isValidIndex;
 
+/* Returns if the glyph at glyphIndex is valid or not */
+- (BOOL) isValidGlyphIndex: (unsigned int)glyphIndex;
+
 /* Copies displayed glyphs to glyphArray for glyphRange. Returns the number
 of glyphs actually copied to the array. NSRangeException of the range is
 invalid (extends beyond the end of glyphs). */

Source/GSLayoutManager.m

@@ -719,6 +719,20 @@ not completely accurate).
   return r->glyphs[glyphIndex].g;
 }
 
+- (BOOL) isValidGlyphIndex: (unsigned int)glyphIndex
+{
+ if (glyphIndex == (unsigned int)-1)
+    return NO;
+
+  if (glyphs->glyph_length <= glyphIndex)
+    {
+      return NO;
+    }
+  else 
+    {
+      return YES;
+    }
+}
 
 - (unsigned int) getGlyphs: (NSGlyph *)glyphArray
 	range: (NSRange)glyphRange