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/* go-type-identity.c -- hash and equality identity functions.
Copyright 2009 The Go Authors. All rights reserved.
Use of this source code is governed by a BSD-style
license that can be found in the LICENSE file. */
#include <stddef.h>
#include "runtime.h"
#include "go-type.h"
/* An identity hash function for a type. This is used for types where
we can simply use the type value itself as a hash code. This is
true of, e.g., integers and pointers. */
uintptr_t
__go_type_hash_identity (const void *key, uintptr_t key_size)
{
uintptr_t ret;
uintptr_t i;
const unsigned char *p;
if (key_size <= 8)
{
union
{
uint64 v;
unsigned char a[8];
} u;
u.v = 0;
#ifdef WORDS_BIGENDIAN
__builtin_memcpy (&u.a[8 - key_size], key, key_size);
#else
__builtin_memcpy (&u.a[0], key, key_size);
#endif
if (sizeof (uintptr_t) >= 8)
return (uintptr_t) u.v;
else
return (uintptr_t) ((u.v >> 32) ^ (u.v & 0xffffffff));
}
ret = 5381;
for (i = 0, p = (const unsigned char *) key; i < key_size; i++, p++)
ret = ret * 33 + *p;
return ret;
}
/* An identity equality function for a type. This is used for types
where we can check for equality by checking that the values have
the same bits. */
_Bool
__go_type_equal_identity (const void *k1, const void *k2, uintptr_t key_size)
{
return __builtin_memcmp (k1, k2, key_size) == 0;
}
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