src/port/strtoul.c

   1 /*
   2  * $PostgreSQL$
   3  *
   4  *
   5  * Copyright (c) 1990, 1993
   6  *      The Regents of the University of California.  All rights reserved.
   7  *
   8  * Redistribution and use in source and binary forms, with or without
   9  * modification, are permitted provided that the following conditions
  10  * are met:
  11  * 1. Redistributions of source code must retain the above copyright
  12  *        notice, this list of conditions and the following disclaimer.
  13  * 2. Redistributions in binary form must reproduce the above copyright
  14  *        notice, this list of conditions and the following disclaimer in the
  15  *        documentation and/or other materials provided with the distribution.
  16  * 3. Neither the name of the University nor the names of its contributors
  17  *        may be used to endorse or promote products derived from this software
  18  *        without specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  21  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED.      IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  24  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  25  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  26  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  27  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  28  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  29  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  30  * SUCH DAMAGE.
  31  */
  32
  33 #if defined(LIBC_SCCS) && !defined(lint)
  34 static char sccsid[] = "@(#)strtoul.c   8.1 (Berkeley) 6/4/93";
  35 #endif   /* LIBC_SCCS and not lint */
  36
  37 #include "c.h"
  38
  39 #include <limits.h>
  40 #include <ctype.h>
  41
  42
  43 /*
  44  * Convert a string to an unsigned long integer.
  45  *
  46  * Ignores `locale' stuff.  Assumes that the upper and lower case
  47  * alphabets and digits are each contiguous.
  48  */
  49 unsigned long
  50 strtoul(nptr, endptr, base)
  51 const char *nptr;
  52 char      **endptr;
  53 register int base;
  54 {
  55         register const char *s = nptr;
  56         register unsigned long acc;
  57         register unsigned char c;
  58         register unsigned long cutoff;
  59         register int neg = 0,
  60                                 any,
  61                                 cutlim;
  62
  63         /*
  64          * See strtol for comments as to the logic used.
  65          */
  66         do
  67         {
  68                 c = *s++;
  69         } while (isspace(c));
  70         if (c == '-')
  71         {
  72                 neg = 1;
  73                 c = *s++;
  74         }
  75         else if (c == '+')
  76                 c = *s++;
  77         if ((base == 0 || base == 16) &&
  78                 c == '0' && (*s == 'x' || *s == 'X'))
  79         {
  80                 c = s[1];
  81                 s += 2;
  82                 base = 16;
  83         }
  84         if (base == 0)
  85                 base = c == '0' ? 8 : 10;
  86         cutoff = (unsigned long) ULONG_MAX / (unsigned long) base;
  87         cutlim = (unsigned long) ULONG_MAX % (unsigned long) base;
  88         for (acc = 0, any = 0;; c = *s++)
  89         {
  90                 if (!isascii(c))
  91                         break;
  92                 if (isdigit(c))
  93                         c -= '0';
  94                 else if (isalpha(c))
  95                         c -= isupper(c) ? 'A' - 10 : 'a' - 10;
  96                 else
  97                         break;
  98                 if ((int) c >= base)
  99                         break;
 100                 if (any < 0 || acc > cutoff || (acc == cutoff && (int) c > cutlim))
 101                         any = -1;
 102                 else
 103                 {
 104                         any = 1;
 105                         acc *= base;
 106                         acc += c;
 107                 }
 108         }
 109         if (any < 0)
 110         {
 111                 acc = ULONG_MAX;
 112                 errno = ERANGE;
 113         }
 114         else if (neg)
 115                 acc = -acc;
 116         if (endptr != 0)
 117                 *endptr = (char *) (any ? s - 1 : nptr);
 118         return acc;
 119 }