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  * 3. All advertising materials mentioning features or use of this software
  17  *    must display the following acknowledgement:
  18  *      This product includes software developed by the University of
  19  *      California, Berkeley and its contributors.
  20  * 4. Neither the name of the University nor the names of its contributors
  21  *    may be used to endorse or promote products derived from this software
  22  *    without specific prior written permission.
  23  *
  24  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34  * SUCH DAMAGE.
  35  *
  36  * @(#)mystring.c       8.2 (Berkeley) 5/4/95
  37  * $FreeBSD: src/bin/sh/mystring.c,v 1.10.2.1 2002/07/19 04:38:52 tjr Exp $
  38  * $DragonFly: src/bin/sh/mystring.c,v 1.3 2004/03/19 18:39:41 cpressey Exp $
  39  */
  40
  41 /*
  42  * String functions.
  43  *
  44  *      equal(s1, s2)           Return true if strings are equal.
  45  *      scopy(from, to)         Copy a string.
  46  *      scopyn(from, to, n)     Like scopy, but checks for overflow.
  47  *      number(s)               Convert a string of digits to an integer.
  48  *      is_number(s)            Return true if s is a string of digits.
  49  */
  50
  51 #include <stdlib.h>
  52 #include "shell.h"
  53 #include "syntax.h"
  54 #include "error.h"
  55 #include "mystring.h"
  56
  57
  58 char nullstr[1];                /* zero length string */
  59
  60 /*
  61  * equal - #defined in mystring.h
  62  */
  63
  64 /*
  65  * scopy - #defined in mystring.h
  66  */
  67
  68
  69 /*
  70  * scopyn - copy a string from "from" to "to", truncating the string
  71  *              if necessary.  "To" is always nul terminated, even if
  72  *              truncation is performed.  "Size" is the size of "to".
  73  */
  74
  75 void
  76 scopyn(const char *from, char *to, int size)
  77 {
  78
  79         while (--size > 0) {
  80                 if ((*to++ = *from++) == '\0')
  81                         return;
  82         }
  83         *to = '\0';
  84 }
  85
  86
  87 /*
  88  * prefix -- see if pfx is a prefix of string.
  89  */
  90
  91 int
  92 prefix(const char *pfx, const char *string)
  93 {
  94         while (*pfx) {
  95                 if (*pfx++ != *string++)
  96                         return 0;
  97         }
  98         return 1;
  99 }
 100
 101
 102 /*
 103  * Convert a string of digits to an integer, printing an error message on
 104  * failure.
 105  */
 106
 107 int
 108 number(const char *s)
 109 {
 110         if (! is_number(s))
 111                 error("Illegal number: %s", s);
 112         return atoi(s);
 113 }
 114
 115
 116
 117 /*
 118  * Check for a valid number.  This should be elsewhere.
 119  */
 120
 121 int
 122 is_number(const char *p)
 123 {
 124         do {
 125                 if (! is_digit(*p))
 126                         return 0;
 127         } while (*++p != '\0');
 128         return 1;
 129 }