dash/mystring.c

/*-
 * Copyright (c) 1991, 1993
 *	The Regents of the University of California.  All rights reserved.
 * Copyright (c) 1997-2005
 *	Herbert Xu <herbert@gondor.apana.org.au>.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Kenneth Almquist.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * String functions.
 *
 *	equal(s1, s2)		Return true if strings are equal.
 *	scopy(from, to)		Copy a string.
 *	scopyn(from, to, n)	Like scopy, but checks for overflow.
 *	number(s)		Convert a string of digits to an integer.
 *	is_number(s)		Return true if s is a string of digits.
 */

#include <stdlib.h>
#include "shell.h"
#include "syntax.h"
#include "error.h"
#include "mystring.h"
#include "memalloc.h"
#include "parser.h"
#include "system.h"


char nullstr[1];		/* zero length string */
const char spcstr[] = " ";
const char snlfmt[] = "%s\n";
const char dolatstr[] = { CTLVAR, VSNORMAL|VSQUOTE, '@', '=', '\0' };
const char illnum[] = "Illegal number: %s";
const char homestr[] = "HOME";

/*
 * equal - #defined in mystring.h
 */

/*
 * scopy - #defined in mystring.h
 */


#if 0
/*
 * scopyn - copy a string from "from" to "to", truncating the string
 *		if necessary.  "To" is always nul terminated, even if
 *		truncation is performed.  "Size" is the size of "to".
 */

void
scopyn(const char *from, char *to, int size)
{

	while (--size > 0) {
		if ((*to++ = *from++) == '\0')
			return;
	}
	*to = '\0';
}
#endif


/*
 * prefix -- see if pfx is a prefix of string.
 */

char *
prefix(const char *string, const char *pfx)
{
	while (*pfx) {
		if (*pfx++ != *string++)
			return 0;
	}
	return (char *) string;
}


/*
 * Convert a string of digits to an integer, printing an error message on
 * failure.
 */

int
number(const char *s)
{

	if (! is_number(s))
		sh_error(illnum, s);
	return atoi(s);
}



/*
 * Check for a valid number.  This should be elsewhere.
 */

int
is_number(const char *p)
{
	do {
		if (! is_digit(*p))
			return 0;
	} while (*++p != '\0');
	return 1;
}


/*
 * Produce a possibly single quoted string suitable as input to the shell.
 * The return string is allocated on the stack.
 */

char *
single_quote(const char *s) {
	char *p;

	STARTSTACKSTR(p);

	do {
		char *q;
		size_t len;

		len = strchrnul(s, '\'') - s;

		q = p = makestrspace(len + 3, p);

		*q++ = '\'';
		q = mempcpy(q, s, len);
		*q++ = '\'';
		s += len;

		STADJUST(q - p, p);

		len = strspn(s, "'");
		if (!len)
			break;

		q = p = makestrspace(len + 3, p);

		*q++ = '"';
		q = mempcpy(q, s, len);
		*q++ = '"';
		s += len;

		STADJUST(q - p, p);
	} while (*s);

	USTPUTC(0, p);

	return stackblock();
}

/*
 * Like strdup but works with the ash stack.
 */

char *
sstrdup(const char *p)
{
	size_t len = strlen(p) + 1;
	return memcpy(stalloc(len), p, len);
}

/*
 * Wrapper around strcmp for qsort/bsearch/...
 */
int
pstrcmp(const void *a, const void *b)
{
	return strcmp(*(const char *const *) a, *(const char *const *) b);
}

/*
 * Find a string is in a sorted array.
 */
const char *const *
findstring(const char *s, const char *const *array, size_t nmemb)
{
	return bsearch(&s, array, nmemb, sizeof(const char *), pstrcmp);
}