mach.subproj/mig_strncpy.c

   1 /*
   2  * Copyright (c) 1999 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22 /*
  23  * Mach Operating System
  24  * Copyright (c) 1991,1990,1989 Carnegie Mellon University
  25  * All Rights Reserved.
  26  *
  27  * Permission to use, copy, modify and distribute this software and its
  28  * documentation is hereby granted, provided that both the copyright
  29  * notice and this permission notice appear in all copies of the
  30  * software, derivative works or modified versions, and any portions
  31  * thereof, and that both notices appear in supporting documentation.
  32  *
  33  * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS"
  34  * CONDITION.  CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
  35  * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
  36  *
  37  * Carnegie Mellon requests users of this software to return to
  38  *
  39  *  Software Distribution Coordinator  or  Software.Distribution@CS.CMU.EDU
  40  *  School of Computer Science
  41  *  Carnegie Mellon University
  42  *  Pittsburgh PA 15213-3890
  43  *
  44  * any improvements or extensions that they make and grant Carnegie Mellon
  45  * the rights to redistribute these changes.
  46  */
  47 /*
  48  * mig_strncpy.c - by Joshua Block
  49  *
  50  * mig_strncpy -- Bounded string copy.  Does what the library routine strncpy
  51  * OUGHT to do:  Copies the (null terminated) string in src into dest, a
  52  * buffer of length len.  Assures that the copy is still null terminated
  53  * and doesn't overflow the buffer, truncating the copy if necessary.
  54  *
  55  * Parameters:
  56  *
  57  *     dest - Pointer to destination buffer.
  58  *
  59  *     src - Pointer to source string.
  60  *
  61  *     len - Length of destination buffer.
  62  *
  63  * Result:
  64  *      length of string copied, INCLUDING the trailing 0.
  65  */
  66 #include <mach/mig_errors.h>
  67
  68 int
  69 mig_strncpy(
  70     register char *dest,
  71     register char *src,
  72     register int len)
  73 {
  74     register int i;
  75
  76     if (len <= 0)
  77         return 0;
  78
  79     for (i=1; i<len; i++)
  80         if (! (*dest++ = *src++))
  81             return i;
  82
  83     *dest = '\0';
  84     return i;
  85 }