1/***************************************************************************
2 * _ _ ____ _
3 * Project ___| | | | _ \| |
4 * / __| | | | |_) | |
5 * | (__| |_| | _ <| |___
6 * \___|\___/|_| \_\_____|
7 *
8 * Copyright (C) 1998 - 2022, Daniel Stenberg, <[email protected]>, 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.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 * SPDX-License-Identifier: curl
22 *
23 ***************************************************************************/
24
25#include <errno.h>
26#include "curl_setup.h"
27
28#include "strtoofft.h"
29
30/*
31 * NOTE:
32 *
33 * In the ISO C standard (IEEE Std 1003.1), there is a strtoimax() function we
34 * could use in case strtoll() doesn't exist... See
35 * https://www.opengroup.org/onlinepubs/009695399/functions/strtoimax.html
36 */
37
38#if (SIZEOF_CURL_OFF_T > SIZEOF_LONG)
39# ifdef HAVE_STRTOLL
40# define strtooff strtoll
41# else
42# if defined(_MSC_VER) && (_MSC_VER >= 1300) && (_INTEGRAL_MAX_BITS >= 64)
43# if defined(_SAL_VERSION)
44 _Check_return_ _CRTIMP __int64 __cdecl _strtoi64(
45 _In_z_ const char *_String,
46 _Out_opt_ _Deref_post_z_ char **_EndPtr, _In_ int _Radix);
47# else
48 _CRTIMP __int64 __cdecl _strtoi64(const char *_String,
49 char **_EndPtr, int _Radix);
50# endif
51# define strtooff _strtoi64
52# else
53# define PRIVATE_STRTOOFF 1
54# endif
55# endif
56#else
57# define strtooff strtol
58#endif
59
60#ifdef PRIVATE_STRTOOFF
61
62/* Range tests can be used for alphanum decoding if characters are consecutive,
63 like in ASCII. Else an array is scanned. Determine this condition now. */
64
65#if('9' - '0') != 9 || ('Z' - 'A') != 25 || ('z' - 'a') != 25
66
67#define NO_RANGE_TEST
68
69static const char valchars[] =
70 "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
71#endif
72
73static int get_char(char c, int base);
74
75/**
76 * Custom version of the strtooff function. This extracts a curl_off_t
77 * value from the given input string and returns it.
78 */
79static curl_off_t strtooff(const char *nptr, char **endptr, int base)
80{
81 char *end;
82 int is_negative = 0;
83 int overflow;
84 int i;
85 curl_off_t value = 0;
86 curl_off_t newval;
87
88 /* Skip leading whitespace. */
89 end = (char *)nptr;
90 while(ISSPACE(end[0])) {
91 end++;
92 }
93
94 /* Handle the sign, if any. */
95 if(end[0] == '-') {
96 is_negative = 1;
97 end++;
98 }
99 else if(end[0] == '+') {
100 end++;
101 }
102 else if(end[0] == '\0') {
103 /* We had nothing but perhaps some whitespace -- there was no number. */
104 if(endptr) {
105 *endptr = end;
106 }
107 return 0;
108 }
109
110 /* Handle special beginnings, if present and allowed. */
111 if(end[0] == '0' && end[1] == 'x') {
112 if(base == 16 || base == 0) {
113 end += 2;
114 base = 16;
115 }
116 }
117 else if(end[0] == '0') {
118 if(base == 8 || base == 0) {
119 end++;
120 base = 8;
121 }
122 }
123
124 /* Matching strtol, if the base is 0 and it doesn't look like
125 * the number is octal or hex, we assume it's base 10.
126 */
127 if(base == 0) {
128 base = 10;
129 }
130
131 /* Loop handling digits. */
132 value = 0;
133 overflow = 0;
134 for(i = get_char(end[0], base);
135 i != -1;
136 end++, i = get_char(end[0], base)) {
137 newval = base * value + i;
138 if(newval < value) {
139 /* We've overflowed. */
140 overflow = 1;
141 break;
142 }
143 else
144 value = newval;
145 }
146
147 if(!overflow) {
148 if(is_negative) {
149 /* Fix the sign. */
150 value *= -1;
151 }
152 }
153 else {
154 if(is_negative)
155 value = CURL_OFF_T_MIN;
156 else
157 value = CURL_OFF_T_MAX;
158
159 errno = ERANGE;
160 }
161
162 if(endptr)
163 *endptr = end;
164
165 return value;
166}
167
168/**
169 * Returns the value of c in the given base, or -1 if c cannot
170 * be interpreted properly in that base (i.e., is out of range,
171 * is a null, etc.).
172 *
173 * @param c the character to interpret according to base
174 * @param base the base in which to interpret c
175 *
176 * @return the value of c in base, or -1 if c isn't in range
177 */
178static int get_char(char c, int base)
179{
180#ifndef NO_RANGE_TEST
181 int value = -1;
182 if(c <= '9' && c >= '0') {
183 value = c - '0';
184 }
185 else if(c <= 'Z' && c >= 'A') {
186 value = c - 'A' + 10;
187 }
188 else if(c <= 'z' && c >= 'a') {
189 value = c - 'a' + 10;
190 }
191#else
192 const char *cp;
193 int value;
194
195 cp = memchr(valchars, c, 10 + 26 + 26);
196
197 if(!cp)
198 return -1;
199
200 value = cp - valchars;
201
202 if(value >= 10 + 26)
203 value -= 26; /* Lowercase. */
204#endif
205
206 if(value >= base) {
207 value = -1;
208 }
209
210 return value;
211}
212#endif /* Only present if we need strtoll, but don't have it. */
213
214/*
215 * Parse a *positive* up to 64 bit number written in ascii.
216 */
217CURLofft curlx_strtoofft(const char *str, char **endp, int base,
218 curl_off_t *num)
219{
220 char *end;
221 curl_off_t number;
222 errno = 0;
223 *num = 0; /* clear by default */
224
225 while(*str && ISSPACE(*str))
226 str++;
227 if('-' == *str) {
228 if(endp)
229 *endp = (char *)str; /* didn't actually move */
230 return CURL_OFFT_INVAL; /* nothing parsed */
231 }
232 number = strtooff(str, &end, base);
233 if(endp)
234 *endp = end;
235 if(errno == ERANGE)
236 /* overflow/underflow */
237 return CURL_OFFT_FLOW;
238 else if(str == end)
239 /* nothing parsed */
240 return CURL_OFFT_INVAL;
241
242 *num = number;
243 return CURL_OFFT_OK;
244}
245