sdcc/device/lib/strtoul.c

   1 /*---------------------------------------------------------------------
   2    strtoul() - convert a string to a unsigned long int and return it
   3
   4    Copyright (C) 2018-2023, Philipp Klaus Krause . krauseph@informatik.uni-freiburg.de
   5
   6    This library is free software; you can redistribute it and/or modify it
   7    under the terms of the GNU General Public License as published by the
   8    Free Software Foundation; either version 2, or (at your option) any
   9    later version.
  10
  11    This library is distributed in the hope that it will be useful,
  12    but WITHOUT ANY WARRANTY; without even the implied warranty of
  13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14    GNU General Public License for more details.
  15
  16    You should have received a copy of the GNU General Public License
  17    along with this library; see the file COPYING. If not, write to the
  18    Free Software Foundation, 51 Franklin Street, Fifth Floor, Boston,
  19    MA 02110-1301, USA.
  20
  21    As a special exception, if you link this library with other files,
  22    some of which are compiled with SDCC, to produce an executable,
  23    this library does not by itself cause the resulting executable to
  24    be covered by the GNU General Public License. This exception does
  25    not however invalidate any other reasons why the executable file
  26    might be covered by the GNU General Public License.
  27 -------------------------------------------------------------------------*/
  28
  29 #include <stdlib.h>
  30
  31 #include <stdbool.h>
  32 #include <ctype.h>
  33 #include <string.h>
  34 #if !defined(__SDCC_pic14) && !defined(__SDCC_pic16)
  35 #include <stdckdint.h>
  36 #endif
  37 #include <limits.h>
  38 #include <errno.h>
  39
  40 static signed char _isdigit(const char c, unsigned char base)
  41 {
  42   unsigned char v;
  43
  44   if (c >= '0' && c <= '9')
  45     v = c - '0';
  46   else if (c >= 'a' && c <='z')
  47     v = c - 'a' + 10;
  48   else if (c >= 'A' && c <='Z')
  49     v = c - 'A' + 10;
  50   else
  51     return (-1);
  52
  53   if (v >= base)
  54     return (-1);
  55
  56   return (v);
  57 }
  58
  59 // NOTE for maintenance: strtoull, wcstoul and wcstoull have been derived from strtoul
  60
  61 unsigned long int strtoul(const char *nptr, char **endptr, int base)
  62 {
  63   const char *ptr = nptr;
  64   unsigned long int ret;
  65   bool range_error = false;
  66   bool neg = false;
  67   unsigned char b = base;
  68
  69   while (isblank (*ptr))
  70     ptr++;
  71
  72   // Handle sign.
  73   switch(*ptr)
  74     {
  75     case '-':
  76       neg = true;
  77     case '+':
  78       ptr++;
  79     }
  80
  81   // base not specified.
  82   if (!b)
  83     {
  84       if (!strncmp (ptr, "0x", 2) || !strncmp (ptr, "0X", 2))
  85         {
  86           b = 16;
  87           ptr += 2;
  88         }
  89       else if (!strncmp (ptr, "0b", 2) || !strncmp (ptr, "0B", 2))
  90         {
  91           b = 2;
  92           ptr += 2;
  93         }
  94       else if (*ptr == '0')
  95         {
  96           b = 8;
  97           ptr++;
  98         }
  99       else
 100         b = 10;
 101     }
 102   // Handle optional hex prefix.
 103   else if (b == 16 && (!strncmp (ptr, "0x", 2) || !strncmp (ptr, "0X", 2)))
 104     ptr += 2;
 105   else if (b == 2 && (!strncmp (ptr, "0b", 2) || !strncmp (ptr, "0B", 2)))
 106     ptr += 2;
 107
 108   // Empty sequence conversion error
 109   if (_isdigit (*ptr, b) < 0)
 110     {
 111       if (endptr)
 112         *endptr = (char*)nptr;
 113       return (0);
 114     }
 115
 116   for (ret = 0;; ptr++)
 117     {
 118       signed char digit = _isdigit (*ptr, b);
 119
 120       if (digit < 0)
 121         break;
 122
 123 #if !defined(__SDCC_pic14) && !defined(__SDCC_pic16)
 124       range_error |= ckd_mul (&ret, ret, b);
 125       range_error |= ckd_add (&ret, ret, digit);
 126 #else
 127       unsigned long int oldret = ret;
 128       ret *= b;
 129       if (ret < oldret)
 130         range_error = true;
 131       ret += (unsigned char)digit;
 132 #warning INEXACT RANGE ERROR CHECK WILL NOT REPORT ALL OVERFLOWS (fix by implementing ckd_mul and ckd_add)
 133 #endif
 134     }
 135
 136   if (endptr)
 137     *endptr = (char*)ptr;
 138
 139   if (range_error)
 140     {
 141       errno = ERANGE;
 142       return (ULONG_MAX);
 143     }
 144
 145   return (neg ? -ret : ret);
 146 }
 147