49 lines
1.4 KiB
C
49 lines
1.4 KiB
C
/* Support for using a string as a hash key.
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Copyright (C) 2006-2026 Free Software Foundation, Inc.
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This file is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation; either version 2.1 of the
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License, or (at your option) any later version.
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This file is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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#include <config.h>
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/* Specification. */
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#include "hashkey-string.h"
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#include <limits.h>
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#include <string.h>
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bool
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hashkey_string_equals (const void *x1, const void *x2)
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{
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const char *s1 = (const char *) x1;
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const char *s2 = (const char *) x2;
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return streq (s1, s2);
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}
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#define SIZE_BITS (sizeof (size_t) * CHAR_BIT)
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/* A hash function for NUL-terminated 'const char *' strings using
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the method described by Bruno Haible.
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See https://www.haible.de/bruno/hashfunc.html. */
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size_t
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hashkey_string_hash (const void *x)
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{
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const char *s = (const char *) x;
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size_t h = 0;
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for (; *s; s++)
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h = *s + ((h << 9) | (h >> (SIZE_BITS - 9)));
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return h;
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}
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