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