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 or Corporation for National Research Initiatives or
  13 CNRI not be used in advertising or publicity pertaining to
  14 distribution of the software without specific, written prior
  15 permission.
  16
  17 While CWI is the initial source for this software, a modified version
  18 is made available by the Corporation for National Research Initiatives
  19 (CNRI) at the Internet address ftp://ftp.python.org.
  20
  21 STICHTING MATHEMATISCH CENTRUM AND CNRI DISCLAIM ALL WARRANTIES WITH
  22 REGARD TO THIS SOFTWARE, INCLUDING ALL IMPLIED WARRANTIES OF
  23 MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL STICHTING MATHEMATISCH
  24 CENTRUM OR CNRI BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL
  25 DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR
  26 PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
  27 TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR
  28 PERFORMANCE OF THIS SOFTWARE.
  29
  30 ******************************************************************/
  31
  32 #include "Python.h"
  33
  34 #if defined(__sgi) && defined(WITH_THREAD) && !defined(_SGI_MP_SOURCE)
  35 #define _SGI_MP_SOURCE
  36 #endif
  37
  38 /* Convert a possibly signed character to a nonnegative int */
  39 /* XXX This assumes characters are 8 bits wide */
  40 #ifdef __CHAR_UNSIGNED__
  41 #define Py_CHARMASK(c)          (c)
  42 #else
  43 #define Py_CHARMASK(c)          ((c) & 0xff)
  44 #endif
  45
  46 /* strtol and strtoul, renamed to avoid conflicts */
  47
  48 /*
  49 **      strtoul
  50 **              This is a general purpose routine for converting
  51 **              an ascii string to an integer in an arbitrary base.
  52 **              Leading white space is ignored.  If 'base' is zero
  53 **              it looks for a leading 0, 0x or 0X to tell which
  54 **              base.  If these are absent it defaults to 10.
  55 **              Base must be 0 or between 2 and 36 (inclusive).
  56 **              If 'ptr' is non-NULL it will contain a pointer to
  57 **              the end of the scan.
  58 **              Errors due to bad pointers will probably result in
  59 **              exceptions - we don't check for them.
  60 */
  61
  62 #include <ctype.h>
  63 #include <errno.h>
  64
  65 unsigned long
  66 PyOS_strtoul(str, ptr, base)
  67 register char * str;
  68 char **         ptr;
  69 int             base;
  70 {
  71     register unsigned long      result; /* return value of the function */
  72     register int                c;      /* current input character */
  73     register unsigned long      temp;   /* used in overflow testing */
  74     int                         ovf;    /* true if overflow occurred */
  75
  76     result = 0;
  77     ovf = 0;
  78
  79 /* catch silly bases */
  80     if (base != 0 && (base < 2 || base > 36))
  81     {
  82         if (ptr)
  83             *ptr = str;
  84         return 0;
  85     }
  86
  87 /* skip leading white space */
  88     while (*str && isspace(Py_CHARMASK(*str)))
  89         str++;
  90
  91 /* check for leading 0 or 0x for auto-base or base 16 */
  92     switch (base)
  93     {
  94     case 0:             /* look for leading 0, 0x or 0X */
  95         if (*str == '0')
  96         {
  97             str++;
  98             if (*str == 'x' || *str == 'X')
  99             {
 100                 str++;
 101                 base = 16;
 102             }
 103             else
 104                 base = 8;
 105         }
 106         else
 107             base = 10;
 108         break;
 109
 110     case 16:    /* skip leading 0x or 0X */
 111         if (*str == '0' && (*(str+1) == 'x' || *(str+1) == 'X'))
 112             str += 2;
 113         break;
 114     }
 115
 116 /* do the conversion */
 117     while ((c = Py_CHARMASK(*str)) != '\0')
 118     {
 119         if (isdigit(c) && c - '0' < base)
 120             c -= '0';
 121         else
 122         {
 123             if (isupper(c))
 124                 c = tolower(c);
 125             if (c >= 'a' && c <= 'z')
 126                 c -= 'a' - 10;
 127             else        /* non-"digit" character */
 128                 break;
 129             if (c >= base)      /* non-"digit" character */
 130                 break;
 131         }
 132         temp = result;
 133         result = result * base + c;
 134 #ifndef MPW
 135         if(base == 10) {
 136                 if(((long)(result - c) / base != (long)temp))   /* overflow */
 137                         ovf = 1;
 138         }
 139         else {
 140                 if ((result - c) / base != temp)        /* overflow */
 141                         ovf = 1;
 142         }
 143 #endif
 144         str++;
 145     }
 146
 147 /* set pointer to point to the last character scanned */
 148     if (ptr)
 149         *ptr = str;
 150     if (ovf)
 151     {
 152         result = (unsigned long) ~0L;
 153         errno = ERANGE;
 154     }
 155     return result;
 156 }
 157
 158 long
 159 PyOS_strtol(str, ptr, base)
 160 char *  str;
 161 char ** ptr;
 162 int     base;
 163 {
 164         long result;
 165         char sign;
 166
 167         while (*str && isspace(Py_CHARMASK(*str)))
 168                 str++;
 169
 170         sign = *str;
 171         if (sign == '+' || sign == '-')
 172                 str++;
 173
 174         result = (long) PyOS_strtoul(str, ptr, base);
 175
 176         /* Signal overflow if the result appears negative,
 177            except for the largest negative integer */
 178         if (result < 0 && !(sign == '-' && result == -result)) {
 179                 errno = ERANGE;
 180                 result = 0x7fffffff;
 181         }
 182
 183         if (sign == '-')
 184                 result = -result;
 185
 186         return result;
 187 }