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1 /***************************************************************************
2  *                                  _   _ ____  _
3  *  Project                     ___| | | |  _ \| |
4  *                             / __| | | | |_) | |
5  *                            | (__| |_| |  _ <| |___
6  *                             \___|\___/|_| \_\_____|
7  *
8  * Copyright (C) 1998 - 2017, 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 https://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  ***************************************************************************/
22 
23 #include <errno.h>
24 #include "curl_setup.h"
25 
26 #include "strtoofft.h"
27 
28 /*
29  * NOTE:
30  *
31  * In the ISO C standard (IEEE Std 1003.1), there is a strtoimax() function we
32  * could use in case strtoll() doesn't exist...  See
33  * https://www.opengroup.org/onlinepubs/009695399/functions/strtoimax.html
34  */
35 
36 #if (SIZEOF_CURL_OFF_T > SIZEOF_LONG)
37 #  ifdef HAVE_STRTOLL
38 #    define strtooff strtoll
39 #  else
40 #    if defined(_MSC_VER) && (_MSC_VER >= 1300) && (_INTEGRAL_MAX_BITS >= 64)
41 #      if defined(_SAL_VERSION)
42          _Check_return_ _CRTIMP __int64 __cdecl _strtoi64(
43              _In_z_ const char *_String,
44              _Out_opt_ _Deref_post_z_ char **_EndPtr, _In_ int _Radix);
45 #      else
46          _CRTIMP __int64 __cdecl _strtoi64(const char *_String,
47                                            char **_EndPtr, int _Radix);
48 #      endif
49 #      define strtooff _strtoi64
50 #    else
51 #      define PRIVATE_STRTOOFF 1
52 #    endif
53 #  endif
54 #else
55 #  define strtooff strtol
56 #endif
57 
58 #ifdef PRIVATE_STRTOOFF
59 
60 /* Range tests can be used for alphanum decoding if characters are consecutive,
61    like in ASCII. Else an array is scanned. Determine this condition now. */
62 
63 #if('9' - '0') != 9 || ('Z' - 'A') != 25 || ('z' - 'a') != 25
64 
65 #define NO_RANGE_TEST
66 
67 static const char valchars[] =
68             "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
69 #endif
70 
71 static int get_char(char c, int base);
72 
73 /**
74  * Custom version of the strtooff function.  This extracts a curl_off_t
75  * value from the given input string and returns it.
76  */
strtooff(const char * nptr,char ** endptr,int base)77 static curl_off_t strtooff(const char *nptr, char **endptr, int base)
78 {
79   char *end;
80   int is_negative = 0;
81   int overflow;
82   int i;
83   curl_off_t value = 0;
84   curl_off_t newval;
85 
86   /* Skip leading whitespace. */
87   end = (char *)nptr;
88   while(ISSPACE(end[0])) {
89     end++;
90   }
91 
92   /* Handle the sign, if any. */
93   if(end[0] == '-') {
94     is_negative = 1;
95     end++;
96   }
97   else if(end[0] == '+') {
98     end++;
99   }
100   else if(end[0] == '\0') {
101     /* We had nothing but perhaps some whitespace -- there was no number. */
102     if(endptr) {
103       *endptr = end;
104     }
105     return 0;
106   }
107 
108   /* Handle special beginnings, if present and allowed. */
109   if(end[0] == '0' && end[1] == 'x') {
110     if(base == 16 || base == 0) {
111       end += 2;
112       base = 16;
113     }
114   }
115   else if(end[0] == '0') {
116     if(base == 8 || base == 0) {
117       end++;
118       base = 8;
119     }
120   }
121 
122   /* Matching strtol, if the base is 0 and it doesn't look like
123    * the number is octal or hex, we assume it's base 10.
124    */
125   if(base == 0) {
126     base = 10;
127   }
128 
129   /* Loop handling digits. */
130   value = 0;
131   overflow = 0;
132   for(i = get_char(end[0], base);
133       i != -1;
134       end++, i = get_char(end[0], base)) {
135     newval = base * value + i;
136     if(newval < value) {
137       /* We've overflowed. */
138       overflow = 1;
139       break;
140     }
141     else
142       value = newval;
143   }
144 
145   if(!overflow) {
146     if(is_negative) {
147       /* Fix the sign. */
148       value *= -1;
149     }
150   }
151   else {
152     if(is_negative)
153       value = CURL_OFF_T_MIN;
154     else
155       value = CURL_OFF_T_MAX;
156 
157     errno = ERANGE;
158   }
159 
160   if(endptr)
161     *endptr = end;
162 
163   return value;
164 }
165 
166 /**
167  * Returns the value of c in the given base, or -1 if c cannot
168  * be interpreted properly in that base (i.e., is out of range,
169  * is a null, etc.).
170  *
171  * @param c     the character to interpret according to base
172  * @param base  the base in which to interpret c
173  *
174  * @return  the value of c in base, or -1 if c isn't in range
175  */
get_char(char c,int base)176 static int get_char(char c, int base)
177 {
178 #ifndef NO_RANGE_TEST
179   int value = -1;
180   if(c <= '9' && c >= '0') {
181     value = c - '0';
182   }
183   else if(c <= 'Z' && c >= 'A') {
184     value = c - 'A' + 10;
185   }
186   else if(c <= 'z' && c >= 'a') {
187     value = c - 'a' + 10;
188   }
189 #else
190   const char *cp;
191   int value;
192 
193   cp = memchr(valchars, c, 10 + 26 + 26);
194 
195   if(!cp)
196     return -1;
197 
198   value = cp - valchars;
199 
200   if(value >= 10 + 26)
201     value -= 26;                /* Lowercase. */
202 #endif
203 
204   if(value >= base) {
205     value = -1;
206   }
207 
208   return value;
209 }
210 #endif  /* Only present if we need strtoll, but don't have it. */
211 
212 /*
213  * Parse a *positive* up to 64 bit number written in ascii.
214  */
curlx_strtoofft(const char * str,char ** endp,int base,curl_off_t * num)215 CURLofft curlx_strtoofft(const char *str, char **endp, int base,
216                          curl_off_t *num)
217 {
218   char *end;
219   curl_off_t number;
220   errno = 0;
221   *num = 0; /* clear by default */
222 
223   while(*str && ISSPACE(*str))
224     str++;
225   if('-' == *str) {
226     if(endp)
227       *endp = (char *)str; /* didn't actually move */
228     return CURL_OFFT_INVAL; /* nothing parsed */
229   }
230   number = strtooff(str, &end, base);
231   if(endp)
232     *endp = end;
233   if(errno == ERANGE)
234     /* overflow/underflow */
235     return CURL_OFFT_FLOW;
236   else if(str == end)
237     /* nothing parsed */
238     return CURL_OFFT_INVAL;
239 
240   *num = number;
241   return CURL_OFFT_OK;
242 }
243