libgo/runtime/go-type-interface.c

   1 /* go-type-interface.c -- hash and equality interface functions.
   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 "runtime.h"
   8 #include "interface.h"
   9 #include "go-type.h"
  10
  11 /* A hash function for an interface.  */
  12
  13 uintptr_t
  14 __go_type_hash_interface (const void *vval, uintptr_t seed,
  15                           uintptr_t key_size __attribute__ ((unused)))
  16 {
  17   const struct __go_interface *val;
  18   const struct __go_type_descriptor *descriptor;
  19   uintptr_t size;
  20
  21   val = (const struct __go_interface *) vval;
  22   if (val->__methods == NULL)
  23     return 0;
  24   descriptor = (const struct __go_type_descriptor *) val->__methods[0];
  25   if (descriptor->__hashfn == NULL)
  26     runtime_panicstring ("hash of unhashable type");
  27   size = descriptor->__size;
  28   if (__go_is_pointer_type (descriptor))
  29     return __go_call_hashfn (descriptor->__hashfn, &val->__object, seed, size);
  30   else
  31     return __go_call_hashfn (descriptor->__hashfn, val->__object, seed, size);
  32 }
  33
  34 const FuncVal __go_type_hash_interface_descriptor =
  35   { (void *) __go_type_hash_interface };
  36
  37 /* An equality function for an interface.  */
  38
  39 _Bool
  40 __go_type_equal_interface (const void *vv1, const void *vv2,
  41                            uintptr_t key_size __attribute__ ((unused)))
  42 {
  43   const struct __go_interface *v1;
  44   const struct __go_interface *v2;
  45   const struct __go_type_descriptor* v1_descriptor;
  46   const struct __go_type_descriptor* v2_descriptor;
  47
  48   v1 = (const struct __go_interface *) vv1;
  49   v2 = (const struct __go_interface *) vv2;
  50   if (v1->__methods == NULL || v2->__methods == NULL)
  51     return v1->__methods == v2->__methods;
  52   v1_descriptor = (const struct __go_type_descriptor *) v1->__methods[0];
  53   v2_descriptor = (const struct __go_type_descriptor *) v2->__methods[0];
  54   if (!__go_type_descriptors_equal (v1_descriptor, v2_descriptor))
  55     return 0;
  56   if (v1_descriptor->__equalfn == NULL)
  57     runtime_panicstring ("comparing uncomparable types");
  58   if (__go_is_pointer_type (v1_descriptor))
  59     return v1->__object == v2->__object;
  60   else
  61     return __go_call_equalfn (v1_descriptor->__equalfn, v1->__object,
  62                               v2->__object, v1_descriptor->__size);
  63 }
  64
  65 const FuncVal __go_type_equal_interface_descriptor =
  66   { (void *) __go_type_equal_interface };