curl/lib/strtoofft.c

   1 /***************************************************************************
   2  *                                  _   _ ____  _
   3  *  Project                     ___| | | |  _ \| |
   4  *                             / __| | | | |_) | |
   5  *                            | (__| |_| |  _ <| |___
   6  *                             \___|\___/|_| \_\_____|
   7  *
   8  * Copyright (C) 1998 - 2007, Daniel Stenberg, <daniel@haxx.se>, et al.
   9  *
  10  * This software is licensed as described in the file COPYING, which
  11  * you should have received as part of this distribution. The terms
  12  * are also available at http://curl.haxx.se/docs/copyright.html.
  13  *
  14  * You may opt to use, copy, modify, merge, publish, distribute and/or sell
  15  * copies of the Software, and permit persons to whom the Software is
  16  * furnished to do so, under the terms of the COPYING file.
  17  *
  18  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  19  * KIND, either express or implied.
  20  *
  21  * $Id: strtoofft.c,v 1.13 2007-11-05 09:45:09 bagder Exp $
  22  ***************************************************************************/
  23
  24 #include "setup.h"
  25 #include "strtoofft.h"
  26
  27 /*
  28  * NOTE:
  29  *
  30  * In the ISO C standard (IEEE Std 1003.1), there is a strtoimax() function we
  31  * could use in case strtoll() doesn't exist...  See
  32  * http://www.opengroup.org/onlinepubs/009695399/functions/strtoimax.html
  33  */
  34
  35 #ifdef NEED_CURL_STRTOLL
  36 #include <stdlib.h>
  37 #include <ctype.h>
  38 #include <errno.h>
  39
  40 /* Range tests can be used for alphanum decoding if characters are consecutive,
  41    like in ASCII. Else an array is scanned. Determine this condition now. */
  42
  43 #if('9' - '0') != 9 || ('Z' - 'A') != 25 || ('z' - 'a') != 25
  44 #include <string.h>
  45
  46 #define NO_RANGE_TEST
  47
  48 static const char valchars[] =
  49             "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  50 #endif
  51
  52 static int get_char(char c, int base);
  53
  54 /**
  55  * Emulated version of the strtoll function.  This extracts a long long
  56  * value from the given input string and returns it.
  57  */
  58 curl_off_t
  59 curlx_strtoll(const char *nptr, char **endptr, int base)
  60 {
  61   char *end;
  62   int is_negative = 0;
  63   int overflow;
  64   int i;
  65   curl_off_t value = 0;
  66   curl_off_t newval;
  67
  68   /* Skip leading whitespace. */
  69   end = (char *)nptr;
  70   while(ISSPACE(end[0])) {
  71     end++;
  72   }
  73
  74   /* Handle the sign, if any. */
  75   if(end[0] == '-') {
  76     is_negative = 1;
  77     end++;
  78   }
  79   else if(end[0] == '+') {
  80     end++;
  81   }
  82   else if(end[0] == '\0') {
  83     /* We had nothing but perhaps some whitespace -- there was no number. */
  84     if(endptr) {
  85       *endptr = end;
  86     }
  87     return 0;
  88   }
  89
  90   /* Handle special beginnings, if present and allowed. */
  91   if(end[0] == '0' && end[1] == 'x') {
  92     if(base == 16 || base == 0) {
  93       end += 2;
  94       base = 16;
  95     }
  96   }
  97   else if(end[0] == '0') {
  98     if(base == 8 || base == 0) {
  99       end++;
 100       base = 8;
 101     }
 102   }
 103
 104   /* Matching strtol, if the base is 0 and it doesn't look like
 105    * the number is octal or hex, we assume it's base 10.
 106    */
 107   if(base == 0) {
 108     base = 10;
 109   }
 110
 111   /* Loop handling digits. */
 112   value = 0;
 113   overflow = 0;
 114   for (i = get_char(end[0], base);
 115        i != -1;
 116        end++, i = get_char(end[0], base)) {
 117     newval = base * value + i;
 118     if(newval < value) {
 119       /* We've overflowed. */
 120       overflow = 1;
 121       break;
 122     }
 123     else
 124       value = newval;
 125   }
 126
 127   if(!overflow) {
 128     if(is_negative) {
 129       /* Fix the sign. */
 130       value *= -1;
 131     }
 132   }
 133   else {
 134     if(is_negative)
 135       value = CURL_LLONG_MIN;
 136     else
 137       value = CURL_LLONG_MAX;
 138
 139     SET_ERRNO(ERANGE);
 140   }
 141
 142   if(endptr)
 143     *endptr = end;
 144
 145   return value;
 146 }
 147
 148 /**
 149  * Returns the value of c in the given base, or -1 if c cannot
 150  * be interpreted properly in that base (i.e., is out of range,
 151  * is a null, etc.).
 152  *
 153  * @param c     the character to interpret according to base
 154  * @param base  the base in which to interpret c
 155  *
 156  * @return  the value of c in base, or -1 if c isn't in range
 157  */
 158 static int get_char(char c, int base)
 159 {
 160 #ifndef NO_RANGE_TEST
 161   int value = -1;
 162   if(c <= '9' && c >= '0') {
 163     value = c - '0';
 164   }
 165   else if(c <= 'Z' && c >= 'A') {
 166     value = c - 'A' + 10;
 167   }
 168   else if(c <= 'z' && c >= 'a') {
 169     value = c - 'a' + 10;
 170   }
 171 #else
 172   const char * cp;
 173   int value;
 174
 175   cp = memchr(valchars, c, 10 + 26 + 26);
 176
 177   if(!cp)
 178     return -1;
 179
 180   value = cp - valchars;
 181
 182   if(value >= 10 + 26)
 183     value -= 26;                /* Lowercase. */
 184 #endif
 185
 186   if(value >= base) {
 187     value = -1;
 188   }
 189
 190   return value;
 191 }
 192 #endif  /* Only present if we need strtoll, but don't have it. */