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b5cc329c UD |
1 | /* Copyright (C) 1991, 1997, 2003, 2004 Free Software Foundation, Inc. |
2 | This file is part of the GNU C Library. | |
3 | ||
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. | |
8 | ||
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. | |
13 | ||
14 | You should have received a copy of the GNU Lesser General Public | |
59ba27a6 PE |
15 | License along with the GNU C Library; if not, see |
16 | <http://www.gnu.org/licenses/>. */ | |
b5cc329c UD |
17 | |
18 | #include <string.h> | |
19 | #include <memcopy.h> | |
20 | ||
21 | ||
22 | char * | |
23 | __strncpy_chk (s1, s2, n, s1len) | |
24 | char *s1; | |
25 | const char *s2; | |
26 | size_t n; | |
27 | size_t s1len; | |
28 | { | |
29 | reg_char c; | |
30 | char *s = s1; | |
31 | ||
32 | if (__builtin_expect (s1len < n, 0)) | |
33 | __chk_fail (); | |
34 | ||
35 | --s1; | |
36 | ||
37 | if (n >= 4) | |
38 | { | |
39 | size_t n4 = n >> 2; | |
40 | ||
41 | for (;;) | |
42 | { | |
43 | c = *s2++; | |
44 | *++s1 = c; | |
45 | if (c == '\0') | |
46 | break; | |
47 | c = *s2++; | |
48 | *++s1 = c; | |
49 | if (c == '\0') | |
50 | break; | |
51 | c = *s2++; | |
52 | *++s1 = c; | |
53 | if (c == '\0') | |
54 | break; | |
55 | c = *s2++; | |
56 | *++s1 = c; | |
57 | if (c == '\0') | |
58 | break; | |
59 | if (--n4 == 0) | |
60 | goto last_chars; | |
61 | } | |
62 | n = n - (s1 - s) - 1; | |
63 | if (n == 0) | |
64 | return s; | |
65 | goto zero_fill; | |
66 | } | |
67 | ||
68 | last_chars: | |
69 | n &= 3; | |
70 | if (n == 0) | |
71 | return s; | |
72 | ||
73 | do | |
74 | { | |
75 | c = *s2++; | |
76 | *++s1 = c; | |
77 | if (--n == 0) | |
78 | return s; | |
79 | } | |
80 | while (c != '\0'); | |
81 | ||
82 | zero_fill: | |
83 | do | |
84 | *++s1 = '\0'; | |
85 | while (--n > 0); | |
86 | ||
87 | return s; | |
88 | } |