93 lines
2.1 KiB
C
93 lines
2.1 KiB
C
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/* Copyright (C) 1993, 1995-1997, 2002-2003, 2005-2007, 2009-2020 Free Software
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* Foundation, Inc.
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NOTE: The canonical source of this file is maintained with the GNU C Library.
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Bugs can be reported to bug-glibc@gnu.org.
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This program is free software: you can redistribute it and/or modify it
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 3 of the License, or any
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later version.
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This program 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 General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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/* This is almost copied from strncpy.c, written by Torbjorn Granlund. */
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#include <config.h>
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/* Specification. */
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#include <string.h>
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#ifndef weak_alias
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# define __stpncpy stpncpy
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#endif
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/* Copy no more than N bytes of SRC to DST, returning a pointer past the
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last non-NUL byte written into DST. */
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char *
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(__stpncpy) (char *dest, const char *src, size_t n)
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{
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char c;
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char *s = dest;
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if (n >= 4)
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{
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size_t n4 = n >> 2;
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for (;;)
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{
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c = *src++;
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*dest++ = c;
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if (c == '\0')
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break;
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c = *src++;
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*dest++ = c;
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if (c == '\0')
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break;
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c = *src++;
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*dest++ = c;
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if (c == '\0')
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break;
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c = *src++;
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*dest++ = c;
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if (c == '\0')
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break;
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if (--n4 == 0)
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goto last_chars;
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}
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n -= dest - s;
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goto zero_fill;
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}
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last_chars:
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n &= 3;
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if (n == 0)
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return dest;
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for (;;)
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{
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c = *src++;
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--n;
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*dest++ = c;
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if (c == '\0')
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break;
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if (n == 0)
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return dest;
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}
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zero_fill:
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while (n-- > 0)
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dest[n] = '\0';
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return dest - 1;
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}
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#ifdef weak_alias
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weak_alias (__stpncpy, stpncpy)
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#endif
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