Home | History | Annotate | Line # | Download | only in sh
mystring.c revision 1.1 
      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[] = "@(#)mystring.c	5.1 (Berkeley) 3/7/91";
     39 #endif /* not lint */
     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  *	strchr(s, c)		Find first occurance of c in s.
     48  *	bcopy(from, to, n)	Copy a block of memory.
     49  *	number(s)		Convert a string of digits to an integer.
     50  *	is_number(s)		Return true if s is a string of digits.
     51  */
     52 
     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 /*
     63  * scopyn - copy a string from "from" to "to", truncating the string
     64  *		if necessary.  "To" is always nul terminated, even if
     65  *		truncation is performed.  "Size" is the size of "to".
     66  */
     67 
     68 void
     69 scopyn(from, to, size)
     70 	register char const *from;
     71 	register char *to;
     72 	register int size;
     73 	{
     74 
     75 	while (--size > 0) {
     76 		if ((*to++ = *from++) == '\0')
     77 			return;
     78 	}
     79 	*to = '\0';
     80 }
     81 
     82 
     83 /*
     84  * strchr - find first occurrence of a character in a string.
     85  */
     86 
     87 #ifndef SYS5
     88 char *
     89 mystrchr(s, charwanted)
     90 	char const *s;
     91 	register char charwanted;
     92 	{
     93 	register char const *scan;
     94 
     95 	/*
     96 	 * The odd placement of the two tests is so NUL is findable.
     97 	 */
     98 	for (scan = s ; *scan != charwanted ; )	/* ++ moved down for opt. */
     99 		if (*scan++ == '\0')
    100 			return NULL;
    101 	return (char *)scan;
    102 }
    103 #endif
    104 
    105 
    106 
    107 /*
    108  * bcopy - copy bytes
    109  *
    110  * This routine was derived from code by Henry Spencer.
    111  */
    112 
    113 void
    114 mybcopy(src, dst, length)
    115 	pointer dst;
    116 	const pointer src;
    117 	register int length;
    118 	{
    119 	register char *d = dst;
    120 	register char *s = src;
    121 
    122 	while (--length >= 0)
    123 		*d++ = *s++;
    124 }
    125 
    126 
    127 /*
    128  * prefix -- see if pfx is a prefix of string.
    129  */
    130 
    131 int
    132 prefix(pfx, string)
    133 	register char const *pfx;
    134 	register char const *string;
    135 	{
    136 	while (*pfx) {
    137 		if (*pfx++ != *string++)
    138 			return 0;
    139 	}
    140 	return 1;
    141 }
    142 
    143 
    144 /*
    145  * Convert a string of digits to an integer, printing an error message on
    146  * failure.
    147  */
    148 
    149 int
    150 number(s)
    151 	const char *s;
    152 	{
    153 
    154 	if (! is_number(s))
    155 		error2("Illegal number", (char *)s);
    156 	return atoi(s);
    157 }
    158 
    159 
    160 
    161 /*
    162  * Check for a valid number.  This should be elsewhere.
    163  */
    164 
    165 int
    166 is_number(p)
    167 	register const char *p;
    168 	{
    169 	do {
    170 		if (! is_digit(*p))
    171 			return 0;
    172 	} while (*++p != '\0');
    173 	return 1;
    174 }
    175