Merge pull request #242 from gnustep/NSCollectionViewLayout_branch

This branch is to support methods needed by NSCollectionView layout methods.   Added NSIndexMethods needed.

Headers/Foundation/NSIndexPath.h

@@ -72,6 +72,23 @@ GS_EXPORT_CLASS
  */
 + (id) indexPathWithIndexes: (NSUInteger*)indexes length: (NSUInteger)length;
 
+#if OS_API_VERSION(MAC_OS_X_VERSION_10_11,GS_API_LATEST)
+/**
+ * Return a path containing an item number and section.
+ */
++ (NSIndexPath *) indexPathForItem: (NSInteger)item inSection: (NSInteger)section;
+
+/**
+ * Return an index number identifying an item in a collection view
+ */
+- (NSInteger) item;
+
+/**
+ * Return an index number identifying a section in a collection view
+ */
+- (NSInteger) section;
+#endif
+  
 /**
  * Compares other with the receiver.<br />
  * Returns NSOrderedSame if the two are identical.<br />

Source/NSIndexPath.m

@@ -64,6 +64,16 @@ static	NSIndexPath	*dummy = nil;
   return AUTORELEASE(o);
 }
 
++ (NSIndexPath *) indexPathForItem: (NSInteger)item inSection: (NSInteger)section;
+{
+  NSUInteger idxs[2];
+
+  idxs[0] = (NSUInteger)section;
+  idxs[1] = (NSUInteger)item;
+  
+  return [self indexPathWithIndexes: idxs length: 2];
+}
+
 + (void) initialize
 {
   if (empty == nil)
@@ -198,6 +208,16 @@ static	NSIndexPath	*dummy = nil;
     }
 }
 
+- (NSInteger) item
+{
+  return (NSInteger)[self indexAtPosition: 1];
+}
+
+- (NSInteger) section
+{
+  return (NSInteger)[self indexAtPosition: 0];
+}
+
 - (void) getIndexes: (NSUInteger*)aBuffer
 {
   memcpy(aBuffer, _indexes, _length * sizeof(NSUInteger));