stdlib/FreeBSD/strtoimax.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  * 4. Neither the name of the University nor the names of its contributors
  14  *    may be used to endorse or promote products derived from this software
  15  *    without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  18  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  19  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  20  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  21  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  22  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  23  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  24  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  25  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  26  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  27  * SUCH DAMAGE.
  28  */
  29
  30 #if defined(LIBC_SCCS) && !defined(lint)
  31 static char sccsid[] = "from @(#)strtol.c       8.1 (Berkeley) 6/4/93";
  32 #endif /* LIBC_SCCS and not lint */
  33 #include <sys/cdefs.h>
  34 __FBSDID("$FreeBSD: src/lib/libc/stdlib/strtoimax.c,v 1.12 2007/01/09 00:28:10 imp Exp $");
  35
  36 #include <ctype.h>
  37 #include <errno.h>
  38 #include <stdlib.h>
  39 #include <inttypes.h>
  40
  41 /*
  42  * Convert a string to an intmax_t integer.
  43  *
  44  * Assumes that the upper and lower case
  45  * alphabets and digits are each contiguous.
  46  */
  47 intmax_t
  48 strtoimax(const char * __restrict nptr, char ** __restrict endptr, int base)
  49 {
  50         const char *s;
  51         uintmax_t acc;
  52         char c;
  53         uintmax_t cutoff;
  54         int neg, any, cutlim;
  55
  56         /*
  57          * Skip white space and pick up leading +/- sign if any.
  58          * If base is 0, allow 0x for hex and 0 for octal, else
  59          * assume decimal; if base is already 16, allow 0x.
  60          */
  61         s = nptr;
  62         do {
  63                 c = *s++;
  64         } while (isspace((unsigned char)c));
  65         if (c == '-') {
  66                 neg = 1;
  67                 c = *s++;
  68         } else {
  69                 neg = 0;
  70                 if (c == '+')
  71                         c = *s++;
  72         }
  73         if ((base == 0 || base == 16) &&
  74             c == '0' && (*s == 'x' || *s == 'X') &&
  75             ((s[1] >= '0' && s[1] <= '9') ||
  76             (s[1] >= 'A' && s[1] <= 'F') ||
  77             (s[1] >= 'a' && s[1] <= 'f'))) {
  78                 c = s[1];
  79                 s += 2;
  80                 base = 16;
  81         }
  82         if (base == 0)
  83                 base = c == '0' ? 8 : 10;
  84         acc = any = 0;
  85         if (base < 2 || base > 36)
  86                 goto noconv;
  87
  88         /*
  89          * Compute the cutoff value between legal numbers and illegal
  90          * numbers.  That is the largest legal value, divided by the
  91          * base.  An input number that is greater than this value, if
  92          * followed by a legal input character, is too big.  One that
  93          * is equal to this value may be valid or not; the limit
  94          * between valid and invalid numbers is then based on the last
  95          * digit.  For instance, if the range for intmax_t is
  96          * [-9223372036854775808..9223372036854775807] and the input base
  97          * is 10, cutoff will be set to 922337203685477580 and cutlim to
  98          * either 7 (neg==0) or 8 (neg==1), meaning that if we have
  99          * accumulated a value > 922337203685477580, or equal but the
 100          * next digit is > 7 (or 8), the number is too big, and we will
 101          * return a range error.
 102          *
 103          * Set 'any' if any `digits' consumed; make it negative to indicate
 104          * overflow.
 105          */
 106         cutoff = neg ? (uintmax_t)-(INTMAX_MIN + INTMAX_MAX) + INTMAX_MAX
 107             : INTMAX_MAX;
 108         cutlim = cutoff % base;
 109         cutoff /= base;
 110         for ( ; ; c = *s++) {
 111                 if (c >= '0' && c <= '9')
 112                         c -= '0';
 113                 else if (c >= 'A' && c <= 'Z')
 114                         c -= 'A' - 10;
 115                 else if (c >= 'a' && c <= 'z')
 116                         c -= 'a' - 10;
 117                 else
 118                         break;
 119                 if (c >= base)
 120                         break;
 121                 if (any < 0 || acc > cutoff || (acc == cutoff && c > cutlim))
 122                         any = -1;
 123                 else {
 124                         any = 1;
 125                         acc *= base;
 126                         acc += c;
 127                 }
 128         }
 129         if (any < 0) {
 130                 acc = neg ? INTMAX_MIN : INTMAX_MAX;
 131                 errno = ERANGE;
 132         } else if (!any) {
 133 noconv:
 134                 errno = EINVAL;
 135         } else if (neg)
 136                 acc = -acc;
 137         if (endptr != NULL)
 138                 *endptr = (char *)(any ? s - 1 : nptr);
 139         return (acc);
 140 }