Remove ${SHELL} from tst-table.sh/tst-tables.sh
[glibc.git] / string / strncpy.c
blob19d501e06b0e8e04295dbeea976b53d2ee82ef46
1 /* Copyright (C) 1991, 1997, 2003 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
4 The GNU C Library is free software; you can redistribute it and/or
5 modify it under the terms of the GNU Lesser General Public
6 License as published by the Free Software Foundation; either
7 version 2.1 of the License, or (at your option) any later version.
9 The GNU C Library is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 Lesser General Public License for more details.
14 You should have received a copy of the GNU Lesser General Public
15 License along with the GNU C Library; if not, see
16 <http://www.gnu.org/licenses/>. */
18 #include <string.h>
19 #include <memcopy.h>
21 #undef strncpy
23 #ifndef STRNCPY
24 #define STRNCPY strncpy
25 #endif
27 char *
28 STRNCPY (char *s1, const char *s2, size_t n)
30 char c;
31 char *s = s1;
33 --s1;
35 if (n >= 4)
37 size_t n4 = n >> 2;
39 for (;;)
41 c = *s2++;
42 *++s1 = c;
43 if (c == '\0')
44 break;
45 c = *s2++;
46 *++s1 = c;
47 if (c == '\0')
48 break;
49 c = *s2++;
50 *++s1 = c;
51 if (c == '\0')
52 break;
53 c = *s2++;
54 *++s1 = c;
55 if (c == '\0')
56 break;
57 if (--n4 == 0)
58 goto last_chars;
60 n = n - (s1 - s) - 1;
61 if (n == 0)
62 return s;
63 goto zero_fill;
66 last_chars:
67 n &= 3;
68 if (n == 0)
69 return s;
73 c = *s2++;
74 *++s1 = c;
75 if (--n == 0)
76 return s;
78 while (c != '\0');
80 zero_fill:
82 *++s1 = '\0';
83 while (--n > 0);
85 return s;
87 libc_hidden_builtin_def (strncpy)