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 "interface.h"
   9
  10 /* Compare two interface values.  Return 0 for equal, not zero for not
  11    equal (return value is like strcmp).  */
  12
  13 int
  14 __go_empty_interface_compare (struct __go_empty_interface left,
  15                               struct __go_empty_interface right)
  16 {
  17   const struct __go_type_descriptor *left_descriptor;
  18
  19   left_descriptor = left.__type_descriptor;
  20
  21   if (((uintptr_t) left_descriptor & reflectFlags) != 0
  22       || ((uintptr_t) right.__type_descriptor & reflectFlags) != 0)
  23     runtime_panicstring ("invalid interface value");
  24
  25   if (left_descriptor == NULL && right.__type_descriptor == NULL)
  26     return 0;
  27   if (left_descriptor == NULL || right.__type_descriptor == NULL)
  28     return 1;
  29   if (!__go_type_descriptors_equal (left_descriptor,
  30                                     right.__type_descriptor))
  31     return 1;
  32   if (__go_is_pointer_type (left_descriptor))
  33     return left.__object == right.__object ? 0 : 1;
  34   if (!left_descriptor->__equalfn (left.__object, right.__object,
  35                                    left_descriptor->__size))
  36     return 1;
  37   return 0;
  38 }