70 lines
1.9 KiB
C
70 lines
1.9 KiB
C
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/* Copyright (C) 1991 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 Library General Public License as
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published by the Free Software Foundation; either version 2 of the
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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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Library General Public License for more details.
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You should have received a copy of the GNU Library General Public
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License along with the GNU C Library; see the file COPYING.LIB. If
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not, write to the Free Software Foundation, Inc., 675 Mass Ave,
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Cambridge, MA 02139, USA. */
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#include <ansidecl.h>
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#include <string.h>
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#include <memcopy.h>
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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 lexiographically less than, equal to or
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greater than S2. */
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int
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DEFUN(strncmp, (s1, s2, n),
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CONST char *s1 AND CONST char *s2 AND size_t n)
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{
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unsigned reg_char c1 = '\0';
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unsigned reg_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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