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69f63097 | 1 | /* Copyright (C) 1991,1997,2011 Free Software Foundation, Inc. |
c84142e8 | 2 | This file is part of the GNU C Library. |
28f540f4 | 3 | |
c84142e8 | 4 | The GNU C Library is free software; you can redistribute it and/or |
41bdb6e2 AJ |
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. | |
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 | |
41bdb6e2 | 12 | Lesser General Public License for more details. |
28f540f4 | 13 | |
41bdb6e2 | 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/>. */ | |
28f540f4 | 17 | |
28f540f4 | 18 | #include <string.h> |
c84142e8 UD |
19 | |
20 | #ifdef _LIBC | |
21 | # include <memcopy.h> | |
22 | #else | |
23 | typedef char reg_char; | |
24 | #endif | |
28f540f4 | 25 | |
99710781 | 26 | #ifndef STRNCAT |
f3cdd467 | 27 | # undef strncat |
99710781 LD |
28 | # define STRNCAT strncat |
29 | #endif | |
9a0a462c | 30 | |
28f540f4 | 31 | char * |
69f63097 | 32 | STRNCAT (char *s1, const char *s2, size_t n) |
28f540f4 RM |
33 | { |
34 | reg_char c; | |
35 | char *s = s1; | |
36 | ||
37 | /* Find the end of S1. */ | |
38 | do | |
39 | c = *s1++; | |
40 | while (c != '\0'); | |
41 | ||
42 | /* Make S1 point before next character, so we can increment | |
43 | it while memory is read (wins on pipelined cpus). */ | |
44 | s1 -= 2; | |
45 | ||
46 | if (n >= 4) | |
47 | { | |
48 | size_t n4 = n >> 2; | |
49 | do | |
50 | { | |
51 | c = *s2++; | |
52 | *++s1 = c; | |
53 | if (c == '\0') | |
54 | return s; | |
55 | c = *s2++; | |
56 | *++s1 = c; | |
57 | if (c == '\0') | |
58 | return s; | |
59 | c = *s2++; | |
60 | *++s1 = c; | |
61 | if (c == '\0') | |
62 | return s; | |
63 | c = *s2++; | |
64 | *++s1 = c; | |
65 | if (c == '\0') | |
66 | return s; | |
67 | } while (--n4 > 0); | |
68 | n &= 3; | |
69 | } | |
70 | ||
71 | while (n > 0) | |
72 | { | |
73 | c = *s2++; | |
74 | *++s1 = c; | |
75 | if (c == '\0') | |
76 | return s; | |
77 | n--; | |
78 | } | |
79 | ||
80 | if (c != '\0') | |
81 | *++s1 = '\0'; | |
82 | ||
83 | return s; | |
84 | } |