gen.subproj/ppc.subproj/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 /* Copyright (c) 1992, 1997 NeXT Software, Inc.  All rights reserved.
  23  *
  24  *      File:   libc/gen/ppc/strncpy.c
  25  *
  26  *      This file contains machine dependent code for string copy
  27  *
  28  * HISTORY
  29  *  24-Jan-1997 Umesh Vaishampayan (umeshv@NeXT.com)
  30  *      Ported to PPC.
  31  * 24-Nov-92  Derek B Clegg (dclegg@next.com)
  32  *      Created.
  33  */
  34 #import <string.h>
  35
  36 /* This routine should be optimized. */
  37
  38 /* ANSI sez:
  39  *   The `strncpy' function copies not more than `n' characters (characters
  40  *   that follow a null character are not copied) from the array pointed to
  41  *   by `s2' to the array pointed to by `s1'.  If copying takes place between
  42  *   objects that overlap, the behavior is undefined.
  43  *   If the array pointed to by `s2' is a string that is shorter than `n'
  44  *   characters, null characters are appended to the copy in the array
  45  *   pointed to by `s1', until `n' characters in all have been written.
  46  *   The `strncpy' function returns the value of `s1'.  [4.11.2.4]
  47  */
  48 char *
  49 strncpy(char *s1, const char *s2, size_t n)
  50 {
  51     char *s = s1;
  52     while (n > 0 && *s2 != '\0') {
  53         *s++ = *s2++;
  54         --n;
  55     }
  56     while (n > 0) {
  57         *s++ = '\0';
  58         --n;
  59     }
  60     return s1;
  61 }