cpython/Python/mystrtoul.c at 61c7249759ce88465ea655d5c19d17d03ff3f74b · python/cpython · GitHub

History

291 lines (262 loc) · 8.14 KB

Raw

100

101

102

103

104

105

106

107

108

109

110

111

112

113

114

115

116

117

118

119

120

121

122

123

124

125

126

127

128

129

130

131

132

133

134

135

136

137

138

139

140

141

142

143

144

145

146

147

148

149

150

151

152

153

154

155

156

157

158

159

160

161

162

163

164

165

166

167

168

169

170

171

172

173

174

175

176

177

178

179

180

181

182

183

184

185

186

187

188

189

190

191

192

193

194

195

196

197

198

199

200

201

202

203

204

205

206

207

208

209

210

211

212

213

214

215

216

217

218

219

220

221

222

223

224

225

226

227

228

229

230

231

232

233

234

235

236

237

238

239

240

241

242

243

244

245

246

247

248

249

250

251

252

253

254

255

256

257

258

259

260

261

262

263

264

265

266

267

268

269

270

271

272

273

274

275

276

277

278

279

280

281

282

283

284

285

286

287

288

289

290

291

#include "Python.h"

#include "pycore_long.h" // _PyLong_DigitValue

#if defined(__sgi) && !defined(_SGI_MP_SOURCE)

#define _SGI_MP_SOURCE

#endif

/* strtol and strtoul, renamed to avoid conflicts */

#include <ctype.h>

#ifdef HAVE_ERRNO_H

#include <errno.h>

#endif

/* Static overflow check values for bases 2 through 36.

* smallmax[base] is the largest unsigned long i such that

* i * base doesn't overflow unsigned long.

static const unsigned long smallmax[] = {

0, /* bases 0 and 1 are invalid */

ULONG_MAX / 2,

ULONG_MAX / 3,

ULONG_MAX / 4,

ULONG_MAX / 5,

ULONG_MAX / 6,

ULONG_MAX / 7,

ULONG_MAX / 8,

ULONG_MAX / 9,

ULONG_MAX / 10,

ULONG_MAX / 11,

ULONG_MAX / 12,

ULONG_MAX / 13,

ULONG_MAX / 14,

ULONG_MAX / 15,

ULONG_MAX / 16,

ULONG_MAX / 17,

ULONG_MAX / 18,

ULONG_MAX / 19,

ULONG_MAX / 20,

ULONG_MAX / 21,

ULONG_MAX / 22,

ULONG_MAX / 23,

ULONG_MAX / 24,

ULONG_MAX / 25,

ULONG_MAX / 26,

ULONG_MAX / 27,

ULONG_MAX / 28,

ULONG_MAX / 29,

ULONG_MAX / 30,

ULONG_MAX / 31,

ULONG_MAX / 32,

ULONG_MAX / 33,

ULONG_MAX / 34,

ULONG_MAX / 35,

ULONG_MAX / 36,

};

/* maximum digits that can't ever overflow for bases 2 through 36,

* calculated by [int(math.floor(math.log(2**32, i))) for i in range(2, 37)].

* Note that this is pessimistic if sizeof(long) > 4.

#if SIZEOF_LONG == 4

static const int digitlimit[] = {

0, 0, 32, 20, 16, 13, 12, 11, 10, 10, /* 0 - 9 */

9, 9, 8, 8, 8, 8, 8, 7, 7, 7, /* 10 - 19 */

7, 7, 7, 7, 6, 6, 6, 6, 6, 6, /* 20 - 29 */

6, 6, 6, 6, 6, 6, 6}; /* 30 - 36 */

#elif SIZEOF_LONG == 8

/* [int(math.floor(math.log(2**64, i))) for i in range(2, 37)] */

static const int digitlimit[] = {

0, 0, 64, 40, 32, 27, 24, 22, 21, 20, /* 0 - 9 */

19, 18, 17, 17, 16, 16, 16, 15, 15, 15, /* 10 - 19 */

14, 14, 14, 14, 13, 13, 13, 13, 13, 13, /* 20 - 29 */

13, 12, 12, 12, 12, 12, 12}; /* 30 - 36 */

#else

#error "Need table for SIZEOF_LONG"

#endif

** strtoul

** This is a general purpose routine for converting

** an ascii string to an integer in an arbitrary base.

** Leading white space is ignored. If 'base' is zero

** it looks for a leading 0b, 0o or 0x to tell which

** base. If these are absent it defaults to 10.

** Base must be 0 or between 2 and 36 (inclusive).

** If 'ptr' is non-NULL it will contain a pointer to

** the end of the scan.

** Errors due to bad pointers will probably result in

** exceptions - we don't check for them.

unsigned long

PyOS_strtoul(const char *str, char **ptr, int base)

{

unsigned long result = 0; /* return value of the function */

int c; /* current input character */

int ovlimit; /* required digits to overflow */

/* skip leading white space */

while (*str && Py_ISSPACE(*str))

++str;

/* check for leading 0b, 0o or 0x for auto-base or base 16 */

switch (base) {

case 0: /* look for leading 0b, 0o or 0x */

if (*str == '0') {

++str;

if (*str == 'x' || *str == 'X') {

/* there must be at least one digit after 0x */

if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 16) {

if (ptr)

*ptr = (char *)str;

return 0;

}

++str;

base = 16;

} else if (*str == 'o' || *str == 'O') {

/* there must be at least one digit after 0o */

if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 8) {

if (ptr)

*ptr = (char *)str;

return 0;

}

++str;

base = 8;

} else if (*str == 'b' || *str == 'B') {

/* there must be at least one digit after 0b */

if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 2) {

if (ptr)

*ptr = (char *)str;

return 0;

}

++str;

base = 2;

} else {

/* skip all zeroes... */

while (*str == '0')

++str;

while (Py_ISSPACE(*str))

++str;

if (ptr)

*ptr = (char *)str;

return 0;

}

else

base = 10;

break;

/* even with explicit base, skip leading 0? prefix */

case 16:

if (*str == '0') {

++str;

if (*str == 'x' || *str == 'X') {

/* there must be at least one digit after 0x */

if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 16) {

if (ptr)

*ptr = (char *)str;

return 0;

}

++str;

}

break;

case 8:

if (*str == '0') {

++str;

if (*str == 'o' || *str == 'O') {

/* there must be at least one digit after 0o */

if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 8) {

if (ptr)

*ptr = (char *)str;

return 0;

}

++str;

}

break;

case 2:

if(*str == '0') {

++str;

if (*str == 'b' || *str == 'B') {

/* there must be at least one digit after 0b */

if (_PyLong_DigitValue[Py_CHARMASK(str[1])] >= 2) {

if (ptr)

*ptr = (char *)str;

return 0;

}

++str;

}

break;

}

/* catch silly bases */

if (base < 2 || base > 36) {

if (ptr)

*ptr = (char *)str;

return 0;

}

/* skip leading zeroes */

while (*str == '0')

++str;

/* base is guaranteed to be in [2, 36] at this point */

ovlimit = digitlimit[base];

/* do the conversion until non-digit character encountered */

while ((c = _PyLong_DigitValue[Py_CHARMASK(*str)]) < base) {

if (ovlimit > 0) /* no overflow check required */

result = result * base + c;

else { /* requires overflow check */

unsigned long temp_result;

if (ovlimit < 0) /* guaranteed overflow */

goto overflowed;

/* there could be an overflow */

/* check overflow just from shifting */

if (result > smallmax[base])

goto overflowed;

result *= base;

/* check overflow from the digit's value */

temp_result = result + c;

if (temp_result < result)

goto overflowed;

result = temp_result;

}

++str;

--ovlimit;

}

/* set pointer to point to the last character scanned */

if (ptr)

*ptr = (char *)str;

return result;

overflowed:

if (ptr) {

/* spool through remaining digit characters */

while (_PyLong_DigitValue[Py_CHARMASK(*str)] < base)

++str;

*ptr = (char *)str;

}

errno = ERANGE;

return (unsigned long)-1;

}

/* Checking for overflow in PyOS_strtol is a PITA; see comments

* about PY_ABS_LONG_MIN in longobject.c.

#define PY_ABS_LONG_MIN (0-(unsigned long)LONG_MIN)

long

PyOS_strtol(const char *str, char **ptr, int base)

{

long result;

unsigned long uresult;

char sign;

while (*str && Py_ISSPACE(*str))

str++;

sign = *str;

if (sign == '+' || sign == '-')

str++;

uresult = PyOS_strtoul(str, ptr, base);

if (uresult <= (unsigned long)LONG_MAX) {

result = (long)uresult;

if (sign == '-')

result = -result;

}

else if (sign == '-' && uresult == PY_ABS_LONG_MIN) {

result = LONG_MIN;

}

else {

errno = ERANGE;

result = LONG_MAX;

}

return result;

}

cpython/Python/mystrtoul.c at 61c7249759ce88465ea655d5c19d17d03ff3f74b · python/cpython · GitHub

Uh oh!

Expand file tree

Breadcrumbs

mystrtoul.c

Latest commit

History

Breadcrumbs

mystrtoul.c

File metadata and controls