1 #include "Python.h"
2 #include "pycore_long.h" // _PyLong_DigitValue
3
4 #if defined(__sgi) && !defined(_SGI_MP_SOURCE)
5 #define _SGI_MP_SOURCE
6 #endif
7
8 /* strtol and strtoul, renamed to avoid conflicts */
9
10
11 #include <ctype.h>
12 #ifdef HAVE_ERRNO_H
13 #include <errno.h>
14 #endif
15
16 /* Static overflow check values for bases 2 through 36.
17 * smallmax[base] is the largest unsigned long i such that
18 * i * base doesn't overflow unsigned long.
19 */
20 static const unsigned long smallmax[] = {
21 0, /* bases 0 and 1 are invalid */
22 0,
23 ULONG_MAX / 2,
24 ULONG_MAX / 3,
25 ULONG_MAX / 4,
26 ULONG_MAX / 5,
27 ULONG_MAX / 6,
28 ULONG_MAX / 7,
29 ULONG_MAX / 8,
30 ULONG_MAX / 9,
31 ULONG_MAX / 10,
32 ULONG_MAX / 11,
33 ULONG_MAX / 12,
34 ULONG_MAX / 13,
35 ULONG_MAX / 14,
36 ULONG_MAX / 15,
37 ULONG_MAX / 16,
38 ULONG_MAX / 17,
39 ULONG_MAX / 18,
40 ULONG_MAX / 19,
41 ULONG_MAX / 20,
42 ULONG_MAX / 21,
43 ULONG_MAX / 22,
44 ULONG_MAX / 23,
45 ULONG_MAX / 24,
46 ULONG_MAX / 25,
47 ULONG_MAX / 26,
48 ULONG_MAX / 27,
49 ULONG_MAX / 28,
50 ULONG_MAX / 29,
51 ULONG_MAX / 30,
52 ULONG_MAX / 31,
53 ULONG_MAX / 32,
54 ULONG_MAX / 33,
55 ULONG_MAX / 34,
56 ULONG_MAX / 35,
57 ULONG_MAX / 36,
58 };
59
60 /* maximum digits that can't ever overflow for bases 2 through 36,
61 * calculated by [int(math.floor(math.log(2**32, i))) for i in range(2, 37)].
62 * Note that this is pessimistic if sizeof(long) > 4.
63 */
64 #if SIZEOF_LONG == 4
65 static const int digitlimit[] = {
66 0, 0, 32, 20, 16, 13, 12, 11, 10, 10, /* 0 - 9 */
67 9, 9, 8, 8, 8, 8, 8, 7, 7, 7, /* 10 - 19 */
68 7, 7, 7, 7, 6, 6, 6, 6, 6, 6, /* 20 - 29 */
69 6, 6, 6, 6, 6, 6, 6}; /* 30 - 36 */
70 #elif SIZEOF_LONG == 8
71 /* [int(math.floor(math.log(2**64, i))) for i in range(2, 37)] */
72 static const int digitlimit[] = {
73 0, 0, 64, 40, 32, 27, 24, 22, 21, 20, /* 0 - 9 */
74 19, 18, 17, 17, 16, 16, 16, 15, 15, 15, /* 10 - 19 */
75 14, 14, 14, 14, 13, 13, 13, 13, 13, 13, /* 20 - 29 */
76 13, 12, 12, 12, 12, 12, 12}; /* 30 - 36 */
77 #else
78 #error "Need table for SIZEOF_LONG"
79 #endif
80
81 /*
82 ** strtoul
83 ** This is a general purpose routine for converting
84 ** an ascii string to an integer in an arbitrary base.
85 ** Leading white space is ignored. If 'base' is zero
86 ** it looks for a leading 0b, 0o or 0x to tell which
87 ** base. If these are absent it defaults to 10.
88 ** Base must be 0 or between 2 and 36 (inclusive).
89 ** If 'ptr' is non-NULL it will contain a pointer to
90 ** the end of the scan.
91 ** Errors due to bad pointers will probably result in
92 ** exceptions - we don't check for them.
93 */
94 unsigned long
95 PyOS_strtoul(const char *str, char **ptr, int base)
96 {
97 unsigned long result = 0; /* return value of the function */
98 int c; /* current input character */
99 int ovlimit; /* required digits to overflow */
100
101 /* skip leading white space */
102 while (*str && Py_ISSPACE(*str))
103 ++str;
104
105 /* check for leading 0b, 0o or 0x for auto-base or base 16 */
106 switch (base) {
107 case 0: /* look for leading 0b, 0o or 0x */
108 if (*str == '0') {
109 ++str;
110 if (*str == 'x' || *str == 'X') {
111 /* there must be at least one digit after 0x */
112 if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 16) {
113 if (ptr)
114 *ptr = (char *)str;
115 return 0;
116 }
117 ++str;
118 base = 16;
119 } else if (*str == 'o' || *str == 'O') {
120 /* there must be at least one digit after 0o */
121 if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 8) {
122 if (ptr)
123 *ptr = (char *)str;
124 return 0;
125 }
126 ++str;
127 base = 8;
128 } else if (*str == 'b' || *str == 'B') {
129 /* there must be at least one digit after 0b */
130 if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 2) {
131 if (ptr)
132 *ptr = (char *)str;
133 return 0;
134 }
135 ++str;
136 base = 2;
137 } else {
138 /* skip all zeroes... */
139 while (*str == '0')
140 ++str;
141 while (Py_ISSPACE(*str))
142 ++str;
143 if (ptr)
144 *ptr = (char *)str;
145 return 0;
146 }
147 }
148 else
149 base = 10;
150 break;
151
152 /* even with explicit base, skip leading 0? prefix */
153 case 16:
154 if (*str == '0') {
155 ++str;
156 if (*str == 'x' || *str == 'X') {
157 /* there must be at least one digit after 0x */
158 if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 16) {
159 if (ptr)
160 *ptr = (char *)str;
161 return 0;
162 }
163 ++str;
164 }
165 }
166 break;
167 case 8:
168 if (*str == '0') {
169 ++str;
170 if (*str == 'o' || *str == 'O') {
171 /* there must be at least one digit after 0o */
172 if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 8) {
173 if (ptr)
174 *ptr = (char *)str;
175 return 0;
176 }
177 ++str;
178 }
179 }
180 break;
181 case 2:
182 if(*str == '0') {
183 ++str;
184 if (*str == 'b' || *str == 'B') {
185 /* there must be at least one digit after 0b */
186 if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 2) {
187 if (ptr)
188 *ptr = (char *)str;
189 return 0;
190 }
191 ++str;
192 }
193 }
194 break;
195 }
196
197 /* catch silly bases */
198 if (base < 2 || base > 36) {
199 if (ptr)
200 *ptr = (char *)str;
201 return 0;
202 }
203
204 /* skip leading zeroes */
205 while (*str == '0')
206 ++str;
207
208 /* base is guaranteed to be in [2, 36] at this point */
209 ovlimit = digitlimit[base];
210
211 /* do the conversion until non-digit character encountered */
212 while ((c = _PyLong_DigitValue[Py_CHARMASK(*str)]) < base) {
213 if (ovlimit > 0) /* no overflow check required */
214 result = result * base + c;
215 else { /* requires overflow check */
216 unsigned long temp_result;
217
218 if (ovlimit < 0) /* guaranteed overflow */
219 goto overflowed;
220
221 /* there could be an overflow */
222 /* check overflow just from shifting */
223 if (result > smallmax[base])
224 goto overflowed;
225
226 result *= base;
227
228 /* check overflow from the digit's value */
229 temp_result = result + c;
230 if (temp_result < result)
231 goto overflowed;
232
233 result = temp_result;
234 }
235
236 ++str;
237 --ovlimit;
238 }
239
240 /* set pointer to point to the last character scanned */
241 if (ptr)
242 *ptr = (char *)str;
243
244 return result;
245
246 overflowed:
247 if (ptr) {
248 /* spool through remaining digit characters */
249 while (_PyLong_DigitValue[Py_CHARMASK(*str)] < base)
250 ++str;
251 *ptr = (char *)str;
252 }
253 errno = ERANGE;
254 return (unsigned long)-1;
255 }
256
257 /* Checking for overflow in PyOS_strtol is a PITA; see comments
258 * about PY_ABS_LONG_MIN in longobject.c.
259 */
260 #define PY_ABS_LONG_MIN (0-(unsigned long)LONG_MIN)
261
262 long
263 PyOS_strtol(const char *str, char **ptr, int base)
264 {
265 long result;
266 unsigned long uresult;
267 char sign;
268
269 while (*str && Py_ISSPACE(*str))
270 str++;
271
272 sign = *str;
273 if (sign == '+' || sign == '-')
274 str++;
275
276 uresult = PyOS_strtoul(str, ptr, base);
277
278 if (uresult <= (unsigned long)LONG_MAX) {
279 result = (long)uresult;
280 if (sign == '-')
281 result = -result;
282 }
283 else if (sign == '-' && uresult == PY_ABS_LONG_MIN) {
284 result = LONG_MIN;
285 }
286 else {
287 errno = ERANGE;
288 result = LONG_MAX;
289 }
290 return result;
291 }