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mystring.c revision 1.4 
      1 /*-
      2  * Copyright (c) 1991 The Regents of the University of California.
      3  * 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	5.1 (Berkeley) 3/7/91";*/
     39 static char rcsid[] = "$Id: mystring.c,v 1.4 1993/08/01 18:58:05 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  *	strchr(s, c)		Find first occurance of c in s.
     49  *	bcopy(from, to, n)	Copy a block of memory.
     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 "shell.h"
     55 #include "syntax.h"
     56 #include "error.h"
     57 #include "mystring.h"
     58 
     59 
     60 char nullstr[1];		/* zero length string */
     61 
     62 
     63 /*
     64  * scopyn - copy a string from "from" to "to", truncating the string
     65  *		if necessary.  "To" is always nul terminated, even if
     66  *		truncation is performed.  "Size" is the size of "to".
     67  */
     68 
     69 void
     70 scopyn(from, to, size)
     71 	register char const *from;
     72 	register char *to;
     73 	register int size;
     74 	{
     75 
     76 	while (--size > 0) {
     77 		if ((*to++ = *from++) == '\0')
     78 			return;
     79 	}
     80 	*to = '\0';
     81 }
     82 
     83 
     84 /*
     85  * strchr - find first occurrence of a character in a string.
     86  */
     87 
     88 #ifndef SYS5
     89 char *
     90 mystrchr(s, charwanted)
     91 	char const *s;
     92 	register char charwanted;
     93 	{
     94 	register char const *scan;
     95 
     96 	/*
     97 	 * The odd placement of the two tests is so NUL is findable.
     98 	 */
     99 	for (scan = s ; *scan != charwanted ; )	/* ++ moved down for opt. */
    100 		if (*scan++ == '\0')
    101 			return NULL;
    102 	return (char *)scan;
    103 }
    104 #endif
    105 
    106 
    107 
    108 /*
    109  * bcopy - copy bytes
    110  *
    111  * This routine was derived from code by Henry Spencer.
    112  */
    113 
    114 void
    115 mybcopy(src, dst, length)
    116 	pointer dst;
    117 	const pointer src;
    118 	register int length;
    119 	{
    120 	register char *d = dst;
    121 	register char *s = src;
    122 
    123 	while (--length >= 0)
    124 		*d++ = *s++;
    125 }
    126 
    127 
    128 /*
    129  * prefix -- see if pfx is a prefix of string.
    130  */
    131 
    132 int
    133 prefix(pfx, string)
    134 	register char const *pfx;
    135 	register char const *string;
    136 	{
    137 	while (*pfx) {
    138 		if (*pfx++ != *string++)
    139 			return 0;
    140 	}
    141 	return 1;
    142 }
    143 
    144 
    145 /*
    146  * Convert a string of digits to an integer, printing an error message on
    147  * failure.
    148  */
    149 
    150 int
    151 number(s)
    152 	const char *s;
    153 	{
    154 
    155 	if (! is_number(s))
    156 		error2("Illegal number", (char *)s);
    157 	return atoi(s);
    158 }
    159 
    160 
    161 
    162 /*
    163  * Check for a valid number.  This should be elsewhere.
    164  */
    165 
    166 int
    167 is_number(p)
    168 	register const char *p;
    169 	{
    170 	do {
    171 		if (! is_digit(*p))
    172 			return 0;
    173 	} while (*++p != '\0');
    174 	return 1;
    175 }
    176