Define NOT_IN_libc when compiling benchmark programs
[glibc.git] / string / strncat.c
blobad8e8dc2bdd17bdb1a80d525bdd736da111159c2
1 /* Copyright (C) 1991-2013 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>
20 #ifdef _LIBC
21 # include <memcopy.h>
22 #endif
24 #ifndef STRNCAT
25 # undef strncat
26 # define STRNCAT strncat
27 #endif
29 char *
30 STRNCAT (char *s1, const char *s2, size_t n)
32 char c;
33 char *s = s1;
35 /* Find the end of S1. */
37 c = *s1++;
38 while (c != '\0');
40 /* Make S1 point before next character, so we can increment
41 it while memory is read (wins on pipelined cpus). */
42 s1 -= 2;
44 if (n >= 4)
46 size_t n4 = n >> 2;
49 c = *s2++;
50 *++s1 = c;
51 if (c == '\0')
52 return s;
53 c = *s2++;
54 *++s1 = c;
55 if (c == '\0')
56 return s;
57 c = *s2++;
58 *++s1 = c;
59 if (c == '\0')
60 return s;
61 c = *s2++;
62 *++s1 = c;
63 if (c == '\0')
64 return s;
65 } while (--n4 > 0);
66 n &= 3;
69 while (n > 0)
71 c = *s2++;
72 *++s1 = c;
73 if (c == '\0')
74 return s;
75 n--;
78 if (c != '\0')
79 *++s1 = '\0';
81 return s;