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      1 /*	$NetBSD: mystring.c,v 1.16 2003/08/07 09:05:35 agc 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 1.16 2003/08/07 09:05:35 agc 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 }
    134