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e65caf1f1d
The optimization is achieved by following techniques: > hashing of needle. > hashing avoids scanning of duplicate entries in needle across the string. > initializing the hash table with Vector instructions (VSX) by quadword access. > unrolling when scanning for character in string across hash table.
48 lines
1.3 KiB
C
48 lines
1.3 KiB
C
/* Copyright (C) 1991-2014 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library 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 GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <string.h>
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#undef strspn
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#ifndef STRSPN
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#define STRSPN strspn
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#endif
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/* Return the length of the maximum initial segment
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of S which contains only characters in ACCEPT. */
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size_t
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STRSPN (const char *s, const char *accept)
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{
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const char *p;
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const char *a;
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size_t count = 0;
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for (p = s; *p != '\0'; ++p)
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{
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for (a = accept; *a != '\0'; ++a)
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if (*p == *a)
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break;
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if (*a == '\0')
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return count;
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else
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++count;
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}
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return count;
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}
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libc_hidden_builtin_def (strspn)
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