1 /* go-type-identity.c -- hash and equality identity functions.
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. */
12 /* An identity hash function for a type. This is used for types where
13 we can simply use the type value itself as a hash code. This is
14 true of, e.g., integers and pointers. */
17 __go_type_hash_identity (const void *key
, uintptr_t key_size
)
21 const unsigned char *p
;
31 #ifdef WORDS_BIGENDIAN
32 __builtin_memcpy (&u
.a
[8 - key_size
], key
, key_size
);
34 __builtin_memcpy (&u
.a
[0], key
, key_size
);
36 if (sizeof (uintptr_t) >= 8)
37 return (uintptr_t) u
.v
;
39 return (uintptr_t) ((u
.v
>> 32) ^ (u
.v
& 0xffffffff));
43 for (i
= 0, p
= (const unsigned char *) key
; i
< key_size
; i
++, p
++)
48 /* An identity equality function for a type. This is used for types
49 where we can check for equality by checking that the values have
53 __go_type_equal_identity (const void *k1
, const void *k2
, uintptr_t key_size
)
55 return __builtin_memcmp (k1
, k2
, key_size
) == 0;