2005-08-17 Kelley Cook <kcook@gcc.gnu.org>

[pf3gnuchains/gcc-fork.git] / libobjc / Protocol.m

diff --git a/libobjc/Protocol.m b/libobjc/Protocol.m
index 06a25ac..645e991 100644 (file)
--- a/libobjc/Protocol.m
+++ b/libobjc/Protocol.m
@@ -1,5 +1,5 @@
 /* This file contains the implementation of class Protocol.
-   Copyright (C) 1993 Free Software Foundation, Inc.
+   Copyright (C) 1993, 2004 Free Software Foundation, Inc.
 
 This file is part of GCC. 
 
@@ -15,8 +15,8 @@ GNU General Public License for more details.
 
 You should have received a copy of the GNU General Public License
 along with GCC; see the file COPYING.  If not, write to
-the Free Software Foundation, 59 Temple Place - Suite 330,
-Boston, MA 02111-1307, USA.  */
+the Free Software Foundation, 51 Franklin Street, Fifth Floor,
+Boston, MA 02110-1301, USA.  */
  
 /* As a special exception, if you link this library with files
    compiled with GCC to produce an executable, this does not cause
@@ -56,6 +56,9 @@ struct objc_method_description_list {
   size_t i;
   struct objc_protocol_list* proto_list;
 
+  if (aProtocolObject == nil)
+    return NO;
+
   if (!strcmp(aProtocolObject->protocol_name, self->protocol_name))
     return YES;
 
@@ -129,4 +132,51 @@ struct objc_method_description_list {
   return NULL;
 }
 
+- (unsigned) hash
+{
+  /* Compute a hash of the protocol_name; use the same hash algorithm
+   * that we use for class names; protocol names and class names are
+   * somewhat similar types of string spaces.
+   */
+  int hash = 0, index;
+  
+  for (index = 0; protocol_name[index] != '\0'; index++)
+    {
+      hash = (hash << 4) ^ (hash >> 28) ^ protocol_name[index];
+    }
+
+  hash = (hash ^ (hash >> 10) ^ (hash >> 20));
+
+  return hash;
+}
+
+/*
+ * Equality between formal protocols is only formal (nothing to do
+ * with actually checking the list of methods they have!).  Two formal
+ * Protocols are equal if and only if they have the same name.
+ *
+ * Please note (for comparisons with other implementations) that
+ * checking the names is equivalent to checking that Protocol A
+ * conforms to Protocol B and Protocol B conforms to Protocol A,
+ * because this happens iff they have the same name.  If they have
+ * different names, A conforms to B if and only if A includes B, but
+ * the situation where A includes B and B includes A is a circular
+ * dependency between Protocols which is forbidden by the compiler, so
+ * A conforms to B and B conforms to A with A and B having different
+ * names is an impossible case.
+ */
+- (BOOL) isEqual: (id)obj
+{
+  if (obj == self)
+    return YES;
+
+  if ([obj isKindOf: [Protocol class]])
+    {
+      if (strcmp (protocol_name, ((Protocol *)obj)->protocol_name) == 0)
+       return YES;
+    }
+
+  return NO;
+}
 @end
+