lib/roken/strtoll.c

   1 /*
   2  * Copyright (c) 1992, 1993
   3  *      The Regents of the University of California.  All rights reserved.
   4  *
   5  * Copyright (c) 2011 The FreeBSD Foundation
   6  * All rights reserved.
   7  * Portions of this software were developed by David Chisnall
   8  * under sponsorship from the FreeBSD Foundation.
   9  *
  10  * Redistribution and use in source and binary forms, with or without
  11  * modification, are permitted provided that the following conditions
  12  * are met:
  13  * 1. Redistributions of source code must retain the above copyright
  14  *    notice, this list of conditions and the following disclaimer.
  15  * 2. Redistributions in binary form must reproduce the above copyright
  16  *    notice, this list of conditions and the following disclaimer in the
  17  *    documentation and/or other materials provided with the distribution.
  18  * 4. Neither the name of the University nor the names of its contributors
  19  *    may be used to endorse or promote products derived from this software
  20  *    without specific prior written permission.
  21  *
  22  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  23  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  24  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  25  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  26  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  27  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  28  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  29  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  30  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  31  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  32  * SUCH DAMAGE.
  33  */
  34
  35 #include <config.h>
  36
  37 #include <string.h>
  38
  39 #include "roken.h"
  40
  41 /* #include <sys/cdefs.h> */
  42
  43 #include <limits.h>
  44 #include <errno.h>
  45 #include <ctype.h>
  46 #include <stdlib.h>
  47 #include <stdint.h>
  48
  49 /*
  50  * Convert a string to a long long integer.
  51  *
  52  * Assumes that the upper and lower case
  53  * alphabets and digits are each contiguous.
  54  */
  55 ROKEN_LIB_FUNCTION long long ROKEN_LIB_CALL
  56 strtoll(const char * nptr, char ** endptr, int base)
  57 {
  58     const char *s;
  59     unsigned long long acc;
  60     char c;
  61     unsigned long long cutoff;
  62     int neg, any, cutlim;
  63
  64     /*
  65      * Skip white space and pick up leading +/- sign if any.
  66      * If base is 0, allow 0x for hex and 0 for octal, else
  67      * assume decimal; if base is already 16, allow 0x.
  68      */
  69     s = nptr;
  70     do {
  71         c = *s++;
  72     } while (isspace((unsigned char)c));
  73     if (c == '-') {
  74         neg = 1;
  75         c = *s++;
  76     } else {
  77         neg = 0;
  78         if (c == '+')
  79             c = *s++;
  80     }
  81     if ((base == 0 || base == 16) &&
  82         c == '0' && (*s == 'x' || *s == 'X') &&
  83         ((s[1] >= '0' && s[1] <= '9') ||
  84         (s[1] >= 'A' && s[1] <= 'F') ||
  85         (s[1] >= 'a' && s[1] <= 'f'))) {
  86         c = s[1];
  87         s += 2;
  88         base = 16;
  89     }
  90     if (base == 0)
  91         base = c == '0' ? 8 : 10;
  92     acc = any = 0;
  93     if (base < 2 || base > 36)
  94         goto noconv;
  95
  96     /*
  97      * Compute the cutoff value between legal numbers and illegal
  98      * numbers.  That is the largest legal value, divided by the
  99      * base.  An input number that is greater than this value, if
 100      * followed by a legal input character, is too big.  One that
 101      * is equal to this value may be valid or not; the limit
 102      * between valid and invalid numbers is then based on the last
 103      * digit.  For instance, if the range for quads is
 104      * [-9223372036854775808..9223372036854775807] and the input base
 105      * is 10, cutoff will be set to 922337203685477580 and cutlim to
 106      * either 7 (neg==0) or 8 (neg==1), meaning that if we have
 107      * accumulated a value > 922337203685477580, or equal but the
 108      * next digit is > 7 (or 8), the number is too big, and we will
 109      * return a range error.
 110      *
 111      * Set 'any' if any `digits' consumed; make it negative to indicate
 112      * overflow.
 113      */
 114     cutoff = neg ? (unsigned long long)-(LLONG_MIN + LLONG_MAX) + LLONG_MAX
 115         : LLONG_MAX;
 116     cutlim = cutoff % base;
 117     cutoff /= base;
 118     for ( ; ; c = *s++) {
 119         if (c >= '0' && c <= '9')
 120             c -= '0';
 121         else if (c >= 'A' && c <= 'Z')
 122             c -= 'A' - 10;
 123         else if (c >= 'a' && c <= 'z')
 124             c -= 'a' - 10;
 125         else
 126             break;
 127         if (c >= base)
 128             break;
 129         if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
 130             any = -1;
 131         else {
 132             any = 1;
 133             acc *= base;
 134             acc += c;
 135         }
 136     }
 137     if (any < 0) {
 138         acc = neg ? LLONG_MIN : LLONG_MAX;
 139         errno = ERANGE;
 140     } else if (!any) {
 141 noconv:
 142         errno = EINVAL;
 143     } else if (neg)
 144         acc = -acc;
 145     if (endptr != NULL)
 146         *endptr = (char *)(any ? s - 1 : nptr);
 147     return (acc);
 148 }
 149