75 lines
1.9 KiB
C
75 lines
1.9 KiB
C
/* Copyright (C) 1991-2022 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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<https://www.gnu.org/licenses/>. */
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#include <string.h>
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#include <memcopy.h>
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#undef strncmp
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#ifndef STRNCMP
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#define STRNCMP strncmp
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#endif
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/* Compare no more than N characters of S1 and S2,
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returning less than, equal to or greater than zero
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if S1 is lexicographically less than, equal to or
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greater than S2. */
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int
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STRNCMP (const char *s1, const char *s2, size_t n)
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{
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unsigned char c1 = '\0';
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unsigned char c2 = '\0';
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if (n >= 4)
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{
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size_t n4 = n >> 2;
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do
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{
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c1 = (unsigned char) *s1++;
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c2 = (unsigned char) *s2++;
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if (c1 == '\0' || c1 != c2)
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return c1 - c2;
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c1 = (unsigned char) *s1++;
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c2 = (unsigned char) *s2++;
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if (c1 == '\0' || c1 != c2)
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return c1 - c2;
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c1 = (unsigned char) *s1++;
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c2 = (unsigned char) *s2++;
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if (c1 == '\0' || c1 != c2)
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return c1 - c2;
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c1 = (unsigned char) *s1++;
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c2 = (unsigned char) *s2++;
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if (c1 == '\0' || c1 != c2)
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return c1 - c2;
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} while (--n4 > 0);
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n &= 3;
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}
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while (n > 0)
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{
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c1 = (unsigned char) *s1++;
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c2 = (unsigned char) *s2++;
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if (c1 == '\0' || c1 != c2)
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return c1 - c2;
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n--;
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}
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return c1 - c2;
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}
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libc_hidden_builtin_def (STRNCMP)
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