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mystring.c revision 1.15 
      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. All advertising materials mentioning features or use of this software
     19  *    must display the following acknowledgement:
     20  *	This product includes software developed by the University of
     21  *	California, Berkeley and its contributors.
     22  * 4. Neither the name of the University nor the names of its contributors
     23  *    may be used to endorse or promote products derived from this software
     24  *    without specific prior written permission.
     25  *
     26  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     27  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     28  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     29  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     30  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     31  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     32  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     33  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     34  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     35  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     36  * SUCH DAMAGE.
     37  */
     38 
     39 #include <sys/cdefs.h>
     40 #ifndef lint
     41 #if 0
     42 static char sccsid[] = "@(#)mystring.c	8.2 (Berkeley) 5/4/95";
     43 #else
     44 __RCSID("$NetBSD: mystring.c,v 1.15 2002/11/24 22:35:42 christos Exp $");
     45 #endif
     46 #endif /* not lint */
     47 
     48 /*
     49  * String functions.
     50  *
     51  *	equal(s1, s2)		Return true if strings are equal.
     52  *	scopy(from, to)		Copy a string.
     53  *	scopyn(from, to, n)	Like scopy, but checks for overflow.
     54  *	number(s)		Convert a string of digits to an integer.
     55  *	is_number(s)		Return true if s is a string of digits.
     56  */
     57 
     58 #include <stdlib.h>
     59 #include "shell.h"
     60 #include "syntax.h"
     61 #include "error.h"
     62 #include "mystring.h"
     63 
     64 
     65 char nullstr[1];		/* zero length string */
     66 
     67 /*
     68  * equal - #defined in mystring.h
     69  */
     70 
     71 /*
     72  * scopy - #defined in mystring.h
     73  */
     74 
     75 
     76 /*
     77  * scopyn - copy a string from "from" to "to", truncating the string
     78  *		if necessary.  "To" is always nul terminated, even if
     79  *		truncation is performed.  "Size" is the size of "to".
     80  */
     81 
     82 void
     83 scopyn(const char *from, char *to, int size)
     84 {
     85 
     86 	while (--size > 0) {
     87 		if ((*to++ = *from++) == '\0')
     88 			return;
     89 	}
     90 	*to = '\0';
     91 }
     92 
     93 
     94 /*
     95  * prefix -- see if pfx is a prefix of string.
     96  */
     97 
     98 int
     99 prefix(const char *pfx, const char *string)
    100 {
    101 	while (*pfx) {
    102 		if (*pfx++ != *string++)
    103 			return 0;
    104 	}
    105 	return 1;
    106 }
    107 
    108 
    109 /*
    110  * Convert a string of digits to an integer, printing an error message on
    111  * failure.
    112  */
    113 
    114 int
    115 number(const char *s)
    116 {
    117 
    118 	if (! is_number(s))
    119 		error("Illegal number: %s", s);
    120 	return atoi(s);
    121 }
    122 
    123 
    124 
    125 /*
    126  * Check for a valid number.  This should be elsewhere.
    127  */
    128 
    129 int
    130 is_number(const char *p)
    131 {
    132 	do {
    133 		if (! is_digit(*p))
    134 			return 0;
    135 	} while (*++p != '\0');
    136 	return 1;
    137 }
    138