Python/mystrtoul.c

   1 /***********************************************************
   2 Copyright 1991-1995 by Stichting Mathematisch Centrum, Amsterdam,
   3 The Netherlands.
   4
   5                         All Rights Reserved
   6
   7 Permission to use, copy, modify, and distribute this software and its
   8 documentation for any purpose and without fee is hereby granted,
   9 provided that the above copyright notice appear in all copies and that
  10 both that copyright notice and this permission notice appear in
  11 supporting documentation, and that the names of Stichting Mathematisch
  12 Centrum or CWI not be used in advertising or publicity pertaining to
  13 distribution of the software without specific, written prior permission.
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  15 STICHTING MATHEMATISCH CENTRUM DISCLAIMS ALL WARRANTIES WITH REGARD TO
  16 THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND
  17 FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH CENTRUM BE LIABLE
  18 FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  19 WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  20 ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT
  21 OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  22
  23 ******************************************************************/
  24
  25 #ifdef HAVE_CONFIG_H
  26 #include "config.h"
  27 #endif
  28
  29 /* Convert a possibly signed character to a nonnegative int */
  30 /* XXX This assumes characters are 8 bits wide */
  31 #ifdef __CHAR_UNSIGNED__
  32 #define Py_CHARMASK(c)          (c)
  33 #else
  34 #define Py_CHARMASK(c)          ((c) & 0xff)
  35 #endif
  36
  37 #include "rename2.h"
  38
  39 /* strtol and strtoul, renamed to avoid conflicts */
  40
  41 /*
  42 **      strtoul
  43 **              This is a general purpose routine for converting
  44 **              an ascii string to an integer in an arbitrary base.
  45 **              Leading white space is ignored.  If 'base' is zero
  46 **              it looks for a leading 0, 0x or 0X to tell which
  47 **              base.  If these are absent it defaults to 10.
  48 **              Base must be 0 or between 2 and 36 (inclusive).
  49 **              If 'ptr' is non-NULL it will contain a pointer to
  50 **              the end of the scan.
  51 **              Errors due to bad pointers will probably result in
  52 **              exceptions - we don't check for them.
  53 */
  54
  55 #include <ctype.h>
  56 #include <errno.h>
  57
  58 unsigned long
  59 mystrtoul(str, ptr, base)
  60 register char * str;
  61 char **         ptr;
  62 int             base;
  63 {
  64     register unsigned long      result; /* return value of the function */
  65     register int                c;      /* current input character */
  66     register unsigned long      temp;   /* used in overflow testing */
  67     int                         ovf;    /* true if overflow occurred */
  68
  69     result = 0;
  70     ovf = 0;
  71
  72 /* catch silly bases */
  73     if (base != 0 && (base < 2 || base > 36))
  74     {
  75         if (ptr)
  76             *ptr = str;
  77         return 0;
  78     }
  79
  80 /* skip leading white space */
  81     while (*str && isspace(Py_CHARMASK(*str)))
  82         str++;
  83
  84 /* check for leading 0 or 0x for auto-base or base 16 */
  85     switch (base)
  86     {
  87     case 0:             /* look for leading 0, 0x or 0X */
  88         if (*str == '0')
  89         {
  90             str++;
  91             if (*str == 'x' || *str == 'X')
  92             {
  93                 str++;
  94                 base = 16;
  95             }
  96             else
  97                 base = 8;
  98         }
  99         else
 100             base = 10;
 101         break;
 102
 103     case 16:    /* skip leading 0x or 0X */
 104         if (*str == '0' && (*(str+1) == 'x' || *(str+1) == 'X'))
 105             str += 2;
 106         break;
 107     }
 108
 109 /* do the conversion */
 110     while (c = Py_CHARMASK(*str))
 111     {
 112         if (isdigit(c) && c - '0' < base)
 113             c -= '0';
 114         else
 115         {
 116             if (isupper(c))
 117                 c = tolower(c);
 118             if (c >= 'a' && c <= 'z')
 119                 c -= 'a' - 10;
 120             else        /* non-"digit" character */
 121                 break;
 122             if (c >= base)      /* non-"digit" character */
 123                 break;
 124         }
 125         temp = result;
 126         result = result * base + c;
 127 #ifndef MPW
 128         if ((result - c) / base != temp)        /* overflow */
 129             ovf = 1;
 130 #endif
 131         str++;
 132     }
 133
 134 /* set pointer to point to the last character scanned */
 135     if (ptr)
 136         *ptr = str;
 137     if (ovf)
 138     {
 139         result = ~0;
 140         errno = ERANGE;
 141     }
 142     return result;
 143 }
 144
 145 long
 146 mystrtol(str, ptr, base)
 147 char *  str;
 148 char ** ptr;
 149 int     base;
 150 {
 151         long result;
 152         char sign;
 153
 154         while (*str && isspace(Py_CHARMASK(*str)))
 155                 str++;
 156
 157         sign = *str;
 158         if (sign == '+' || sign == '-')
 159                 str++;
 160
 161         result = (long) mystrtoul(str, ptr, base);
 162
 163         /* Signal overflow if the result appears negative,
 164            except for the largest negative integer */
 165         if (result < 0 && !(sign == '-' && result == -result)) {
 166                 errno = ERANGE;
 167                 result = 0x7fffffff;
 168         }
 169
 170         if (sign == '-')
 171                 result = -result;
 172
 173         return result;
 174 }