openbsd-compat/strtoll.c

   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 */