xref: /illumos-gate/usr/src/contrib/ast/src/lib/libast/string/strncopy.c (revision b30d193948be5a7794d7ae3ba0ed9c2f72c88e0f)
1 /***********************************************************************
2 *                                                                      *
3 *               This software is part of the ast package               *
4 *          Copyright (c) 1985-2011 AT&T Intellectual Property          *
5 *                      and is licensed under the                       *
6 *                 Eclipse Public License, Version 1.0                  *
7 *                    by AT&T Intellectual Property                     *
8 *                                                                      *
9 *                A copy of the License is available at                 *
10 *          http://www.eclipse.org/org/documents/epl-v10.html           *
11 *         (with md5 checksum b35adb5213ca9657e911e9befb180842)         *
12 *                                                                      *
13 *              Information and Software Systems Research               *
14 *                            AT&T Research                             *
15 *                           Florham Park NJ                            *
16 *                                                                      *
17 *                 Glenn Fowler <gsf@research.att.com>                  *
18 *                  David Korn <dgk@research.att.com>                   *
19 *                   Phong Vo <kpv@research.att.com>                    *
20 *                                                                      *
21 ***********************************************************************/
22 #pragma prototyped
23 
24 #include <ast.h>
25 
26 /*
27  * copy up to n bytes of string f into t
28  * trailing 0 always added to t, even if n==0
29  * pointer to the copied 0 returned
30  */
31 
32 char*
strncopy(register char * t,register const char * f,size_t n)33 strncopy(register char* t, register const char* f, size_t n)
34 {
35 	register char*	e = t + n - 1;
36 
37 	do
38 	{
39 		if (t >= e)
40 		{
41 			*t = 0;
42 			return t;
43 		}
44 	} while (*t++ = *f++);
45 	return t - 1;
46 }
47