stdlib/strtoll.c

   1 /*-
   2  * Copyright (c) 1992, 1993
   3  *      The Regents of the University of California.  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[] = "@(#)strtoq.c    8.1 (Berkeley) 6/4/93";
  36 #endif /* LIBC_SCCS and not lint */
  37
  38 #if defined(LIBC_SCCS) && !defined(lint)
  39 static const char rcsid[] =
  40   "$FreeBSD: src/lib/libc/stdlib/strtoll.c,v 1.5.2.1 2001/03/02 09:45:20 obrien Exp $";
  41 #endif
  42
  43 #include <sys/types.h>
  44
  45 #include <limits.h>
  46 #include <errno.h>
  47 #include <ctype.h>
  48 #include <stdlib.h>
  49
  50 /*
  51  * Convert a string to a long long integer.
  52  *
  53  * Ignores `locale' stuff.  Assumes that the upper and lower case
  54  * alphabets and digits are each contiguous.
  55  */
  56 long long
  57 strtoll(nptr, endptr, base)
  58         const char *nptr;
  59         char **endptr;
  60         register int base;
  61 {
  62         register const char *s;
  63         register unsigned long long acc;
  64         register unsigned char c;
  65         register unsigned long long qbase, cutoff;
  66         register int neg, any, cutlim;
  67
  68         /*
  69          * Skip white space and pick up leading +/- sign if any.
  70          * If base is 0, allow 0x for hex and 0 for octal, else
  71          * assume decimal; if base is already 16, allow 0x.
  72          */
  73         s = nptr;
  74         do {
  75                 c = *s++;
  76         } while (isspace(c));
  77         if (c == '-') {
  78                 neg = 1;
  79                 c = *s++;
  80         } else {
  81                 neg = 0;
  82                 if (c == '+')
  83                         c = *s++;
  84         }
  85         if ((base == 0 || base == 16) &&
  86             c == '0' && (*s == 'x' || *s == 'X')) {
  87                 c = s[1];
  88                 s += 2;
  89                 base = 16;
  90         }
  91         if (base == 0)
  92                 base = c == '0' ? 8 : 10;
  93
  94         /*
  95          * Compute the cutoff value between legal numbers and illegal
  96          * numbers.  That is the largest legal value, divided by the
  97          * base.  An input number that is greater than this value, if
  98          * followed by a legal input character, is too big.  One that
  99          * is equal to this value may be valid or not; the limit
 100          * between valid and invalid numbers is then based on the last
 101          * digit.  For instance, if the range for quads is
 102          * [-9223372036854775808..9223372036854775807] and the input base
 103          * is 10, cutoff will be set to 922337203685477580 and cutlim to
 104          * either 7 (neg==0) or 8 (neg==1), meaning that if we have
 105          * accumulated a value > 922337203685477580, or equal but the
 106          * next digit is > 7 (or 8), the number is too big, and we will
 107          * return a range error.
 108          *
 109          * Set any if any `digits' consumed; make it negative to indicate
 110          * overflow.
 111          */
 112         qbase = (unsigned)base;
 113         cutoff = neg ? (unsigned long long)-(LLONG_MIN + LLONG_MAX) + LLONG_MAX
 114             : LLONG_MAX;
 115         cutlim = cutoff % qbase;
 116         cutoff /= qbase;
 117         for (acc = 0, any = 0;; c = *s++) {
 118                 if (!isascii(c))
 119                         break;
 120                 if (isdigit(c))
 121                         c -= '0';
 122                 else if (isalpha(c))
 123                         c -= isupper(c) ? 'A' - 10 : 'a' - 10;
 124                 else
 125                         break;
 126                 if (c >= base)
 127                         break;
 128                 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
 129                         any = -1;
 130                 else {
 131                         any = 1;
 132                         acc *= qbase;
 133                         acc += c;
 134                 }
 135         }
 136         if (any < 0) {
 137                 acc = neg ? LLONG_MIN : LLONG_MAX;
 138                 errno = ERANGE;
 139         } else if (neg)
 140                 acc = -acc;
 141         if (endptr != 0)
 142                 *endptr = (char *)(any ? s - 1 : nptr);
 143         return (acc);
 144 }