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strtouq.c revision 1.6.2.1 
      1 /*-
      2  * Copyright (c) 1992 The Regents of the University of California.
      3  * All rights reserved.
      4  *
      5  * Redistribution and use in source and binary forms, with or without
      6  * modification, are permitted provided that the following conditions
      7  * are met:
      8  * 1. Redistributions of source code must retain the above copyright
      9  *    notice, this list of conditions and the following disclaimer.
     10  * 2. Redistributions in binary form must reproduce the above copyright
     11  *    notice, this list of conditions and the following disclaimer in the
     12  *    documentation and/or other materials provided with the distribution.
     13  * 3. All advertising materials mentioning features or use of this software
     14  *    must display the following acknowledgement:
     15  *	This product includes software developed by the University of
     16  *	California, Berkeley and its contributors.
     17  * 4. Neither the name of the University nor the names of its contributors
     18  *    may be used to endorse or promote products derived from this software
     19  *    without specific prior written permission.
     20  *
     21  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     22  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     23  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     24  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     25  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     26  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     27  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     28  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     29  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     30  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     31  * SUCH DAMAGE.
     32  */
     33 
     34 #if defined(LIBC_SCCS) && !defined(lint)
     35 static char sccsid[] = "@(#)strtouq.c	5.1 (Berkeley) 6/26/92";
     36 #endif /* LIBC_SCCS and not lint */
     37 
     38 #include "namespace.h"
     39 #include <sys/types.h>
     40 
     41 #include <ctype.h>
     42 #include <errno.h>
     43 #include <limits.h>
     44 #include <stdlib.h>
     45 
     46 #ifdef __weak_alias
     47 __weak_alias(strtouq,_strtouq);
     48 __weak_alias(strtoull,_strtouq);
     49 #endif
     50 
     51 /*
     52  * Convert a string to an unsigned quad integer.
     53  *
     54  * Ignores `locale' stuff.  Assumes that the upper and lower case
     55  * alphabets and digits are each contiguous.
     56  */
     57 u_quad_t
     58 strtouq(nptr, endptr, base)
     59 	const char *nptr;
     60 	char **endptr;
     61 	register int base;
     62 {
     63 	register const char *s;
     64 	register u_quad_t acc, cutoff;
     65 	register int c;
     66 	register int neg, any, cutlim;
     67 
     68 	/*
     69 	 * See strtoq for comments as to the logic used.
     70 	 */
     71 	s = nptr;
     72 	do {
     73 		c = (unsigned char) *s++;
     74 	} while (isspace(c));
     75 	if (c == '-') {
     76 		neg = 1;
     77 		c = *s++;
     78 	} else {
     79 		neg = 0;
     80 		if (c == '+')
     81 			c = *s++;
     82 	}
     83 	if ((base == 0 || base == 16) &&
     84 	    c == '0' && (*s == 'x' || *s == 'X')) {
     85 		c = s[1];
     86 		s += 2;
     87 		base = 16;
     88 	}
     89 	if (base == 0)
     90 		base = c == '0' ? 8 : 10;
     91 
     92 	cutoff = UQUAD_MAX / (u_quad_t)base;
     93 	cutlim = UQUAD_MAX % (u_quad_t)base;
     94 	for (acc = 0, any = 0;; c = (unsigned char) *s++) {
     95 		if (isdigit(c))
     96 			c -= '0';
     97 		else if (isalpha(c))
     98 			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
     99 		else
    100 			break;
    101 		if (c >= base)
    102 			break;
    103 		if (any < 0)
    104 			continue;
    105 		if (acc > cutoff || acc == cutoff && c > cutlim) {
    106 			any = -1;
    107 			acc = UQUAD_MAX;
    108 			errno = ERANGE;
    109 		} else {
    110 			any = 1;
    111 			acc *= (u_quad_t)base;
    112 			acc += c;
    113 		}
    114 	}
    115 	if (neg && any > 0)
    116 		acc = -acc;
    117 	if (endptr != 0)
    118 		*endptr = (char *) (any ? s - 1 : nptr);
    119 	return (acc);
    120 }
    121