bin/sh/mystring.c

   1 /*      $NetBSD: mystring.c,v 1.15 2002/11/24 22:35:42 christos Exp $   */
   2
   3 /*-
   4  * Copyright (c) 1991, 1993
   5  *      The Regents of the University of California.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to Berkeley by
   8  * Kenneth Almquist.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 3. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <sys/cdefs.h>
  36 #ifndef lint
  37 #if 0
  38 static char sccsid[] = "@(#)mystring.c  8.2 (Berkeley) 5/4/95";
  39 #else
  40 __RCSID("$NetBSD: mystring.c,v 1.15 2002/11/24 22:35:42 christos Exp $");
  41 #endif
  42 #endif /* not lint */
  43
  44 /*
  45  * String functions.
  46  *
  47  *      equal(s1, s2)           Return true if strings are equal.
  48  *      scopy(from, to)         Copy a string.
  49  *      scopyn(from, to, n)     Like scopy, but checks for overflow.
  50  *      number(s)               Convert a string of digits to an integer.
  51  *      is_number(s)            Return true if s is a string of digits.
  52  */
  53
  54 #include <stdlib.h>
  55 #include "shell.h"
  56 #include "syntax.h"
  57 #include "error.h"
  58 #include "mystring.h"
  59
  60
  61 char nullstr[1];                /* zero length string */
  62
  63 /*
  64  * equal - #defined in mystring.h
  65  */
  66
  67 /*
  68  * scopy - #defined in mystring.h
  69  */
  70
  71
  72 /*
  73  * scopyn - copy a string from "from" to "to", truncating the string
  74  *              if necessary.  "To" is always nul terminated, even if
  75  *              truncation is performed.  "Size" is the size of "to".
  76  */
  77
  78 void
  79 scopyn(const char *from, char *to, int size)
  80 {
  81
  82         while (--size > 0) {
  83                 if ((*to++ = *from++) == '\0')
  84                         return;
  85         }
  86         *to = '\0';
  87 }
  88
  89
  90 /*
  91  * prefix -- see if pfx is a prefix of string.
  92  */
  93
  94 int
  95 prefix(const char *pfx, const char *string)
  96 {
  97         while (*pfx) {
  98                 if (*pfx++ != *string++)
  99                         return 0;
 100         }
 101         return 1;
 102 }
 103
 104
 105 /*
 106  * Convert a string of digits to an integer, printing an error message on
 107  * failure.
 108  */
 109
 110 int
 111 number(const char *s)
 112 {
 113
 114         if (! is_number(s))
 115                 error("Illegal number: %s", s);
 116         return atoi(s);
 117 }
 118
 119
 120
 121 /*
 122  * Check for a valid number.  This should be elsewhere.
 123  */
 124
 125 int
 126 is_number(const char *p)
 127 {
 128         do {
 129                 if (! is_digit(*p))
 130                         return 0;
 131         } while (*++p != '\0');
 132         return 1;
 133 }