openbsd-compat/strtoll.c

   1 /* OPENBSD ORIGINAL: lib/libc/stdlib/strtoll.c */
   2
   3 /*-
   4  * Copyright (c) 1992 The Regents of the University of California.
   5  * 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 "includes.h"
  33 #ifndef HAVE_STRTOLL
  34
  35 #if defined(LIBC_SCCS) && !defined(lint)
  36 static const char rcsid[] = "$OpenBSD: strtoll.c,v 1.4 2005/03/30 18:51:49 pat Exp $";
  37 #endif /* LIBC_SCCS and not lint */
  38
  39 #include <sys/types.h>
  40
  41 #include <ctype.h>
  42 #include <errno.h>
  43 #include <limits.h>
  44 #include <stdlib.h>
  45
  46 /*
  47  * Convert a string to a long long.
  48  *
  49  * Ignores `locale' stuff.  Assumes that the upper and lower case
  50  * alphabets and digits are each contiguous.
  51  */
  52 long long
  53 strtoll(const char *nptr, char **endptr, int base)
  54 {
  55         const char *s;
  56         long long acc, cutoff;
  57         int c;
  58         int neg, any, cutlim;
  59
  60         /*
  61          * Skip white space and pick up leading +/- sign if any.
  62          * If base is 0, allow 0x for hex and 0 for octal, else
  63          * assume decimal; if base is already 16, allow 0x.
  64          */
  65         s = nptr;
  66         do {
  67                 c = (unsigned char) *s++;
  68         } while (isspace(c));
  69         if (c == '-') {
  70                 neg = 1;
  71                 c = *s++;
  72         } else {
  73                 neg = 0;
  74                 if (c == '+')
  75                         c = *s++;
  76         }
  77         if ((base == 0 || base == 16) &&
  78             c == '0' && (*s == 'x' || *s == 'X')) {
  79                 c = s[1];
  80                 s += 2;
  81                 base = 16;
  82         }
  83         if (base == 0)
  84                 base = c == '0' ? 8 : 10;
  85
  86         /*
  87          * Compute the cutoff value between legal numbers and illegal
  88          * numbers.  That is the largest legal value, divided by the
  89          * base.  An input number that is greater than this value, if
  90          * followed by a legal input character, is too big.  One that
  91          * is equal to this value may be valid or not; the limit
  92          * between valid and invalid numbers is then based on the last
  93          * digit.  For instance, if the range for long longs is
  94          * [-9223372036854775808..9223372036854775807] and the input base
  95          * is 10, cutoff will be set to 922337203685477580 and cutlim to
  96          * either 7 (neg==0) or 8 (neg==1), meaning that if we have
  97          * accumulated a value > 922337203685477580, or equal but the
  98          * next digit is > 7 (or 8), the number is too big, and we will
  99          * return a range error.
 100          *
 101          * Set any if any `digits' consumed; make it negative to indicate
 102          * overflow.
 103          */
 104         cutoff = neg ? LLONG_MIN : LLONG_MAX;
 105         cutlim = cutoff % base;
 106         cutoff /= base;
 107         if (neg) {
 108                 if (cutlim > 0) {
 109                         cutlim -= base;
 110                         cutoff += 1;
 111                 }
 112                 cutlim = -cutlim;
 113         }
 114         for (acc = 0, any = 0;; c = (unsigned char) *s++) {
 115                 if (isdigit(c))
 116                         c -= '0';
 117                 else if (isalpha(c))
 118                         c -= isupper(c) ? 'A' - 10 : 'a' - 10;
 119                 else
 120                         break;
 121                 if (c >= base)
 122                         break;
 123                 if (any < 0)
 124                         continue;
 125                 if (neg) {
 126                         if (acc < cutoff || (acc == cutoff && c > cutlim)) {
 127                                 any = -1;
 128                                 acc = LLONG_MIN;
 129                                 errno = ERANGE;
 130                         } else {
 131                                 any = 1;
 132                                 acc *= base;
 133                                 acc -= c;
 134                         }
 135                 } else {
 136                         if (acc > cutoff || (acc == cutoff && c > cutlim)) {
 137                                 any = -1;
 138                                 acc = LLONG_MAX;
 139                                 errno = ERANGE;
 140                         } else {
 141                                 any = 1;
 142                                 acc *= base;
 143                                 acc += c;
 144                         }
 145                 }
 146         }
 147         if (endptr != 0)
 148                 *endptr = (char *) (any ? s - 1 : nptr);
 149         return (acc);
 150 }
 151 #endif /* HAVE_STRTOLL */