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strtouq.c revision 1.10 
      1 /*	$NetBSD: strtouq.c,v 1.10 1998/11/15 17:13:52 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. All advertising materials mentioning features or use of this software
     16  *    must display the following acknowledgement:
     17  *	This product includes software developed by the University of
     18  *	California, Berkeley and its contributors.
     19  * 4. Neither the name of the University nor the names of its contributors
     20  *    may be used to endorse or promote products derived from this software
     21  *    without specific prior written permission.
     22  *
     23  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     24  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     25  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     26  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     27  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     28  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     29  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     30  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     31  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     32  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     33  * SUCH DAMAGE.
     34  */
     35 
     36 #include <sys/cdefs.h>
     37 #if defined(LIBC_SCCS) && !defined(lint)
     38 #if 0
     39 static char sccsid[] = "@(#)strtouq.c	8.1 (Berkeley) 6/4/93";
     40 #else
     41 __RCSID("$NetBSD: strtouq.c,v 1.10 1998/11/15 17:13:52 christos Exp $");
     42 #endif
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 #include "namespace.h"
     46 #include <sys/types.h>
     47 
     48 #include <ctype.h>
     49 #include <errno.h>
     50 #include <limits.h>
     51 #include <stdlib.h>
     52 
     53 /*
     54  * Convert a string to an unsigned quad integer.
     55  *
     56  * Ignores `locale' stuff.  Assumes that the upper and lower case
     57  * alphabets and digits are each contiguous.
     58  */
     59 u_quad_t
     60 _strtouq(nptr, endptr, base)
     61 	const char *nptr;
     62 	char **endptr;
     63 	int base;
     64 {
     65 	const char *s;
     66 	u_quad_t acc, cutoff;
     67 	int c;
     68 	int neg, any, cutlim;
     69 
     70 #ifdef __GNUC__
     71 	/* This outrageous construct just to shut up a GCC warning. */
     72 	(void) &acc;
     73 #endif
     74 
     75 	/*
     76 	 * See strtoq for comments as to the logic used.
     77 	 */
     78 	s = nptr;
     79 	do {
     80 		c = (unsigned char) *s++;
     81 	} while (isspace(c));
     82 	if (c == '-') {
     83 		neg = 1;
     84 		c = *s++;
     85 	} else {
     86 		neg = 0;
     87 		if (c == '+')
     88 			c = *s++;
     89 	}
     90 	if ((base == 0 || base == 16) &&
     91 	    c == '0' && (*s == 'x' || *s == 'X')) {
     92 		c = s[1];
     93 		s += 2;
     94 		base = 16;
     95 	}
     96 	if (base == 0)
     97 		base = c == '0' ? 8 : 10;
     98 
     99 	cutoff = UQUAD_MAX / (u_quad_t)base;
    100 	cutlim = (int)(UQUAD_MAX % (u_quad_t)base);
    101 	for (acc = 0, any = 0;; c = (unsigned char) *s++) {
    102 		if (isdigit(c))
    103 			c -= '0';
    104 		else if (isalpha(c))
    105 			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
    106 		else
    107 			break;
    108 		if (c >= base)
    109 			break;
    110 		if (any < 0)
    111 			continue;
    112 		if (acc > cutoff || (acc == cutoff && c > cutlim)) {
    113 			any = -1;
    114 			acc = UQUAD_MAX;
    115 			errno = ERANGE;
    116 		} else {
    117 			any = 1;
    118 			acc *= (u_quad_t)base;
    119 			acc += c;
    120 		}
    121 	}
    122 	if (neg && any > 0)
    123 		acc = -acc;
    124 	if (endptr != 0)
    125 		/* LINTED interface specification */
    126 		*endptr = (char *)(any ? s - 1 : nptr);
    127 	return (acc);
    128 }
    129