Home | History | Annotate | Line # | Download | only in stdlib
strtouq.c revision 1.18 
      1 /*	$NetBSD: strtouq.c,v 1.18 2005/11/29 03:12:00 christos Exp $	*/
      2 
      3 /*-
      4  * Copyright (c) 1992, 1993
      5  *	The Regents of the University of California.  All rights reserved.
      6  *
      7  * Redistribution and use in source and binary forms, with or without
      8  * modification, are permitted provided that the following conditions
      9  * are met:
     10  * 1. Redistributions of source code must retain the above copyright
     11  *    notice, this list of conditions and the following disclaimer.
     12  * 2. Redistributions in binary form must reproduce the above copyright
     13  *    notice, this list of conditions and the following disclaimer in the
     14  *    documentation and/or other materials provided with the distribution.
     15  * 3. Neither the name of the University nor the names of its contributors
     16  *    may be used to endorse or promote products derived from this software
     17  *    without specific prior written permission.
     18  *
     19  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     20  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     21  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     22  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     23  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     24  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     25  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     26  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     27  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     28  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     29  * SUCH DAMAGE.
     30  */
     31 
     32 #include <sys/cdefs.h>
     33 #if defined(LIBC_SCCS) && !defined(lint)
     34 #if 0
     35 static char sccsid[] = "@(#)strtouq.c	8.1 (Berkeley) 6/4/93";
     36 #else
     37 __RCSID("$NetBSD: strtouq.c,v 1.18 2005/11/29 03:12:00 christos Exp $");
     38 #endif
     39 #endif /* LIBC_SCCS and not lint */
     40 
     41 #include <sys/types.h>
     42 
     43 #include <assert.h>
     44 #include <ctype.h>
     45 #include <errno.h>
     46 #include <limits.h>
     47 #include <stdlib.h>
     48 
     49 /*
     50  * Convert a string to an unsigned quad integer.
     51  *
     52  * Ignores `locale' stuff.  Assumes that the upper and lower case
     53  * alphabets and digits are each contiguous.
     54  */
     55 u_quad_t
     56 strtouq(nptr, endptr, base)
     57 	const char *nptr;
     58 	char **endptr;
     59 	int base;
     60 {
     61 	const char *s;
     62 	u_quad_t acc, cutoff;
     63 	int c;
     64 	int neg, any, cutlim;
     65 
     66 	_DIAGASSERT(nptr != NULL);
     67 	/* endptr may be NULL */
     68 
     69 	/*
     70 	 * See strtoq for comments as to the logic used.
     71 	 */
     72 	s = nptr;
     73 	do {
     74 		c = (unsigned char) *s++;
     75 	} while (isspace(c));
     76 	if (c == '-') {
     77 		neg = 1;
     78 		c = *s++;
     79 	} else {
     80 		neg = 0;
     81 		if (c == '+')
     82 			c = *s++;
     83 	}
     84 	if ((base == 0 || base == 16) &&
     85 	    c == '0' && (*s == 'x' || *s == 'X')) {
     86 		c = s[1];
     87 		s += 2;
     88 		base = 16;
     89 	}
     90 	if (base == 0)
     91 		base = c == '0' ? 8 : 10;
     92 
     93 	cutoff = UQUAD_MAX / (u_quad_t)base;
     94 	cutlim = (int)(UQUAD_MAX % (u_quad_t)base);
     95 	for (acc = 0, any = 0;; c = (unsigned char) *s++) {
     96 		if (isdigit(c))
     97 			c -= '0';
     98 		else if (isalpha(c))
     99 			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
    100 		else
    101 			break;
    102 		if (c >= base)
    103 			break;
    104 		if (any < 0)
    105 			continue;
    106 		if (acc > cutoff || (acc == cutoff && c > cutlim)) {
    107 			any = -1;
    108 			acc = UQUAD_MAX;
    109 			errno = ERANGE;
    110 		} else {
    111 			any = 1;
    112 			acc *= (u_quad_t)base;
    113 			acc += c;
    114 		}
    115 	}
    116 	if (neg && any > 0)
    117 		acc = -acc;
    118 	if (endptr != 0)
    119 		*endptr = __UNCONST(any ? s - 1 : nptr);
    120 	return (acc);
    121 }
    122