libgo/runtime/go-eface-compare.c

   1 /* go-eface-compare.c -- compare two empty values.
   2
   3    Copyright 2010 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 "runtime.h"
   8 #include "go-type.h"
   9 #include "interface.h"
  10
  11 /* Compare two interface values.  Return 0 for equal, not zero for not
  12    equal (return value is like strcmp).  */
  13
  14 intgo
  15 __go_empty_interface_compare (struct __go_empty_interface left,
  16                               struct __go_empty_interface right)
  17 {
  18   const struct __go_type_descriptor *left_descriptor;
  19
  20   left_descriptor = left.__type_descriptor;
  21
  22   if (left_descriptor == NULL && right.__type_descriptor == NULL)
  23     return 0;
  24   if (left_descriptor == NULL || right.__type_descriptor == NULL)
  25     return 1;
  26   if (!__go_type_descriptors_equal (left_descriptor,
  27                                     right.__type_descriptor))
  28     return 1;
  29   if (left_descriptor->__equalfn == NULL)
  30     runtime_panicstring ("comparing uncomparable types");
  31   if (__go_is_pointer_type (left_descriptor))
  32     return left.__object == right.__object ? 0 : 1;
  33   if (!__go_call_equalfn (left_descriptor->__equalfn, left.__object,
  34                           right.__object, left_descriptor->__size))
  35     return 1;
  36   return 0;
  37 }