bin/sh/mystring.c

   1 /*-
   2  * Copyright (c) 1991, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * This code is derived from software contributed to Berkeley by
   6  * Kenneth Almquist.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *    notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *    notice, this list of conditions and the following disclaimer in the
  15  *    documentation and/or other materials provided with the distribution.
  16  * 4. Neither the name of the University nor the names of its contributors
  17  *    may be used to endorse or promote products derived from this software
  18  *    without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  *
  32  * @(#)mystring.c       8.2 (Berkeley) 5/4/95
  33  * $FreeBSD: head/bin/sh/mystring.c 229219 2012-01-01 22:15:38Z jilles $
  34  */
  35
  36 /*
  37  * String functions.
  38  *
  39  *      equal(s1, s2)           Return true if strings are equal.
  40  *      scopy(from, to)         Copy a string.
  41  *      number(s)               Convert a string of digits to an integer.
  42  *      is_number(s)            Return true if s is a string of digits.
  43  */
  44
  45 #include <stdlib.h>
  46 #include "shell.h"
  47 #include "syntax.h"
  48 #include "error.h"
  49 #include "mystring.h"
  50
  51
  52 char nullstr[1];                /* zero length string */
  53
  54 /*
  55  * equal - #defined in mystring.h
  56  */
  57
  58 /*
  59  * scopy - #defined in mystring.h
  60  */
  61
  62
  63 /*
  64  * prefix -- see if pfx is a prefix of string.
  65  */
  66
  67 int
  68 prefix(const char *pfx, const char *string)
  69 {
  70         while (*pfx) {
  71                 if (*pfx++ != *string++)
  72                         return 0;
  73         }
  74         return 1;
  75 }
  76
  77
  78 /*
  79  * Convert a string of digits to an integer, printing an error message on
  80  * failure.
  81  */
  82
  83 int
  84 number(const char *s)
  85 {
  86         if (! is_number(s))
  87                 error("Illegal number: %s", s);
  88         return atoi(s);
  89 }
  90
  91
  92
  93 /*
  94  * Check for a valid number.  This should be elsewhere.
  95  */
  96
  97 int
  98 is_number(const char *p)
  99 {
 100         do {
 101                 if (! is_digit(*p))
 102                         return 0;
 103         } while (*++p != '\0');
 104         return 1;
 105 }