Home | History | Annotate | Download | only in openbsd-compat 
      1 /* $OpenBSD: strtoll.c,v 1.6 2005/11/10 10:00:17 espie Exp $ */
      2 /*-
      3  * Copyright (c) 1992 The Regents of the University of California.
      4  * All rights reserved.
      5  *
      6  * Redistribution and use in source and binary forms, with or without
      7  * modification, are permitted provided that the following conditions
      8  * are met:
      9  * 1. Redistributions of source code must retain the above copyright
     10  *    notice, this list of conditions and the following disclaimer.
     11  * 2. Redistributions in binary form must reproduce the above copyright
     12  *    notice, this list of conditions and the following disclaimer in the
     13  *    documentation and/or other materials provided with the distribution.
     14  * 3. Neither the name of the University nor the names of its contributors
     15  *    may be used to endorse or promote products derived from this software
     16  *    without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
     19  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     20  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     21  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
     22  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     23  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     24  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     25  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     26  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     27  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     28  * SUCH DAMAGE.
     29  */
     30 
     31 /* OPENBSD ORIGINAL: lib/libc/stdlib/strtoll.c */
     32 
     33 #include "includes.h"
     34 #ifndef HAVE_STRTOLL
     35 
     36 #include <sys/types.h>
     37 
     38 #include <ctype.h>
     39 #include <errno.h>
     40 #include <limits.h>
     41 #include <stdlib.h>
     42 
     43 /*
     44  * Convert a string to a long long.
     45  *
     46  * Ignores `locale' stuff.  Assumes that the upper and lower case
     47  * alphabets and digits are each contiguous.
     48  */
     49 long long
     50 strtoll(const char *nptr, char **endptr, int base)
     51 {
     52 	const char *s;
     53 	long long acc, cutoff;
     54 	int c;
     55 	int neg, any, cutlim;
     56 
     57 	/*
     58 	 * Skip white space and pick up leading +/- sign if any.
     59 	 * If base is 0, allow 0x for hex and 0 for octal, else
     60 	 * assume decimal; if base is already 16, allow 0x.
     61 	 */
     62 	s = nptr;
     63 	do {
     64 		c = (unsigned char) *s++;
     65 	} while (isspace(c));
     66 	if (c == '-') {
     67 		neg = 1;
     68 		c = *s++;
     69 	} else {
     70 		neg = 0;
     71 		if (c == '+')
     72 			c = *s++;
     73 	}
     74 	if ((base == 0 || base == 16) &&
     75 	    c == '0' && (*s == 'x' || *s == 'X')) {
     76 		c = s[1];
     77 		s += 2;
     78 		base = 16;
     79 	}
     80 	if (base == 0)
     81 		base = c == '0' ? 8 : 10;
     82 
     83 	/*
     84 	 * Compute the cutoff value between legal numbers and illegal
     85 	 * numbers.  That is the largest legal value, divided by the
     86 	 * base.  An input number that is greater than this value, if
     87 	 * followed by a legal input character, is too big.  One that
     88 	 * is equal to this value may be valid or not; the limit
     89 	 * between valid and invalid numbers is then based on the last
     90 	 * digit.  For instance, if the range for long longs is
     91 	 * [-9223372036854775808..9223372036854775807] and the input base
     92 	 * is 10, cutoff will be set to 922337203685477580 and cutlim to
     93 	 * either 7 (neg==0) or 8 (neg==1), meaning that if we have
     94 	 * accumulated a value > 922337203685477580, or equal but the
     95 	 * next digit is > 7 (or 8), the number is too big, and we will
     96 	 * return a range error.
     97 	 *
     98 	 * Set any if any `digits' consumed; make it negative to indicate
     99 	 * overflow.
    100 	 */
    101 	cutoff = neg ? LLONG_MIN : LLONG_MAX;
    102 	cutlim = cutoff % base;
    103 	cutoff /= base;
    104 	if (neg) {
    105 		if (cutlim > 0) {
    106 			cutlim -= base;
    107 			cutoff += 1;
    108 		}
    109 		cutlim = -cutlim;
    110 	}
    111 	for (acc = 0, any = 0;; c = (unsigned char) *s++) {
    112 		if (isdigit(c))
    113 			c -= '0';
    114 		else if (isalpha(c))
    115 			c -= isupper(c) ? 'A' - 10 : 'a' - 10;
    116 		else
    117 			break;
    118 		if (c >= base)
    119 			break;
    120 		if (any < 0)
    121 			continue;
    122 		if (neg) {
    123 			if (acc < cutoff || (acc == cutoff && c > cutlim)) {
    124 				any = -1;
    125 				acc = LLONG_MIN;
    126 				errno = ERANGE;
    127 			} else {
    128 				any = 1;
    129 				acc *= base;
    130 				acc -= c;
    131 			}
    132 		} else {
    133 			if (acc > cutoff || (acc == cutoff && c > cutlim)) {
    134 				any = -1;
    135 				acc = LLONG_MAX;
    136 				errno = ERANGE;
    137 			} else {
    138 				any = 1;
    139 				acc *= base;
    140 				acc += c;
    141 			}
    142 		}
    143 	}
    144 	if (endptr != 0)
    145 		*endptr = (char *) (any ? s - 1 : nptr);
    146 	return (acc);
    147 }
    148 #endif /* HAVE_STRTOLL */
    149