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mystring.c revision 1.8 
      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 
     37 #ifndef lint
     38 /*static char sccsid[] = "from: @(#)mystring.c	8.1 (Berkeley) 5/31/93";*/
     39 static char *rcsid = "$Id: mystring.c,v 1.8 1994/06/11 16:12:18 mycroft Exp $";
     40 #endif /* not lint */
     41 
     42 /*
     43  * String functions.
     44  *
     45  *	equal(s1, s2)		Return true if strings are equal.
     46  *	scopy(from, to)		Copy a string.
     47  *	scopyn(from, to, n)	Like scopy, but checks for overflow.
     48  *	number(s)		Convert a string of digits to an integer.
     49  *	is_number(s)		Return true if s is a string of digits.
     50  */
     51 
     52 #include <stdlib.h>
     53 #include "shell.h"
     54 #include "syntax.h"
     55 #include "error.h"
     56 #include "mystring.h"
     57 
     58 
     59 char nullstr[1];		/* zero length string */
     60 
     61 /*
     62  * equal - #defined in mystring.h
     63  */
     64 
     65 /*
     66  * scopy - #defined in mystring.h
     67  */
     68 
     69 
     70 /*
     71  * scopyn - copy a string from "from" to "to", truncating the string
     72  *		if necessary.  "To" is always nul terminated, even if
     73  *		truncation is performed.  "Size" is the size of "to".
     74  */
     75 
     76 void
     77 scopyn(from, to, size)
     78 	register char const *from;
     79 	register char *to;
     80 	register int size;
     81 	{
     82 
     83 	while (--size > 0) {
     84 		if ((*to++ = *from++) == '\0')
     85 			return;
     86 	}
     87 	*to = '\0';
     88 }
     89 
     90 
     91 /*
     92  * prefix -- see if pfx is a prefix of string.
     93  */
     94 
     95 int
     96 prefix(pfx, string)
     97 	register char const *pfx;
     98 	register char const *string;
     99 	{
    100 	while (*pfx) {
    101 		if (*pfx++ != *string++)
    102 			return 0;
    103 	}
    104 	return 1;
    105 }
    106 
    107 
    108 /*
    109  * Convert a string of digits to an integer, printing an error message on
    110  * failure.
    111  */
    112 
    113 int
    114 number(s)
    115 	const char *s;
    116 	{
    117 
    118 	if (! is_number(s))
    119 		error2("Illegal number", (char *)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(p)
    131 	register const char *p;
    132 	{
    133 	do {
    134 		if (! is_digit(*p))
    135 			return 0;
    136 	} while (*++p != '\0');
    137 	return 1;
    138 }
    139