libgo/runtime/go-interface-compare.c

   1 /* go-interface-compare.c -- compare two interface values.
   2
   3    Copyright 2009 The Go Authors. All rights reserved.
   4    Use of this source code is governed by a BSD-style
   5    license that can be found in the LICENSE file.  */
   6
   7 #include <stddef.h>
   8
   9 #include "runtime.h"
  10 #include "go-type.h"
  11 #include "interface.h"
  12
  13 /* Compare two interface values.  Return 0 for equal, not zero for not
  14    equal (return value is like strcmp).  */
  15
  16 int
  17 __go_interface_compare (struct __go_interface left,
  18                         struct __go_interface right)
  19 {
  20   const struct __go_type_descriptor *left_descriptor;
  21
  22   if (left.__methods == NULL && right.__methods == NULL)
  23     return 0;
  24   if (left.__methods == NULL || right.__methods == NULL)
  25     return 1;
  26   left_descriptor = left.__methods[0];
  27   if (!__go_type_descriptors_equal (left_descriptor, right.__methods[0]))
  28     return 1;
  29   if (__go_is_pointer_type (left_descriptor))
  30     return left.__object == right.__object ? 0 : 1;
  31   if (!__go_call_equalfn (left_descriptor->__equalfn, left.__object,
  32                           right.__object, left_descriptor->__size))
  33     return 1;
  34   return 0;
  35 }