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c84142e8 UD |
1 | /* Copyright (C) 1991, 1997 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. | |
28f540f4 | 3 | |
c84142e8 UD |
4 | The GNU C Library is free software; you can redistribute it and/or |
5 | modify it under the terms of the GNU Library General Public License as | |
6 | published by the Free Software Foundation; either version 2 of the | |
7 | License, or (at your option) any later version. | |
28f540f4 | 8 | |
c84142e8 UD |
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 | Library General Public License for more details. | |
28f540f4 | 13 | |
c84142e8 UD |
14 | You should have received a copy of the GNU Library General Public |
15 | License along with the GNU C Library; see the file COPYING.LIB. If not, | |
16 | write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, | |
17 | Boston, MA 02111-1307, USA. */ | |
28f540f4 | 18 | |
28f540f4 RM |
19 | #include <string.h> |
20 | #include <memcopy.h> | |
21 | ||
c84142e8 | 22 | |
28f540f4 | 23 | char * |
c84142e8 UD |
24 | strncpy (s1, s2, n) |
25 | char *s1; | |
26 | const char *s2; | |
27 | size_t n; | |
28f540f4 RM |
28 | { |
29 | reg_char c; | |
30 | char *s = s1; | |
31 | ||
32 | --s1; | |
33 | ||
34 | if (n >= 4) | |
35 | { | |
36 | size_t n4 = n >> 2; | |
37 | ||
38 | for (;;) | |
39 | { | |
40 | c = *s2++; | |
41 | *++s1 = c; | |
42 | if (c == '\0') | |
43 | break; | |
44 | c = *s2++; | |
45 | *++s1 = c; | |
46 | if (c == '\0') | |
47 | break; | |
48 | c = *s2++; | |
49 | *++s1 = c; | |
50 | if (c == '\0') | |
51 | break; | |
52 | c = *s2++; | |
53 | *++s1 = c; | |
54 | if (c == '\0') | |
55 | break; | |
56 | if (--n4 == 0) | |
57 | goto last_chars; | |
58 | } | |
59 | n = n - (s1 - s) - 1; | |
60 | if (n == 0) | |
61 | return s; | |
62 | goto zero_fill; | |
63 | } | |
64 | ||
65 | last_chars: | |
66 | n &= 3; | |
67 | if (n == 0) | |
68 | return s; | |
69 | ||
70 | do | |
71 | { | |
72 | c = *s2++; | |
73 | *++s1 = c; | |
74 | if (--n == 0) | |
75 | return s; | |
76 | } | |
77 | while (c != '\0'); | |
78 | ||
79 | zero_fill: | |
80 | do | |
81 | *++s1 = '\0'; | |
82 | while (--n > 0); | |
83 | ||
84 | return s; | |
85 | } |