1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #include "base/strings/string_number_conversions.h" 6 7 #include <ctype.h> 8 #include <errno.h> 9 #include <stdlib.h> 10 #include <wctype.h> 11 12 #include <limits> 13 #include <type_traits> 14 15 #include "base/logging.h" 16 #include "base/numerics/safe_math.h" 17 #include "base/scoped_clear_errno.h" 18 19 namespace base { 20 21 namespace { 22 23 template <typename STR, typename INT> 24 struct IntToStringT { 25 static STR IntToString(INT value) { 26 // log10(2) ~= 0.3 bytes needed per bit or per byte log10(2**8) ~= 2.4. 27 // So round up to allocate 3 output characters per byte, plus 1 for '-'. 28 const size_t kOutputBufSize = 29 3 * sizeof(INT) + std::numeric_limits<INT>::is_signed; 30 31 // Create the string in a temporary buffer, write it back to front, and 32 // then return the substr of what we ended up using. 33 using CHR = typename STR::value_type; 34 CHR outbuf[kOutputBufSize]; 35 36 // The ValueOrDie call below can never fail, because UnsignedAbs is valid 37 // for all valid inputs. 38 typename std::make_unsigned<INT>::type res = 39 CheckedNumeric<INT>(value).UnsignedAbs().ValueOrDie(); 40 41 CHR* end = outbuf + kOutputBufSize; 42 CHR* i = end; 43 do { 44 --i; 45 DCHECK(i != outbuf); 46 *i = static_cast<CHR>((res % 10) + '0'); 47 res /= 10; 48 } while (res != 0); 49 if (IsValueNegative(value)) { 50 --i; 51 DCHECK(i != outbuf); 52 *i = static_cast<CHR>('-'); 53 } 54 return STR(i, end); 55 } 56 }; 57 58 // Utility to convert a character to a digit in a given base 59 template<typename CHAR, int BASE, bool BASE_LTE_10> class BaseCharToDigit { 60 }; 61 62 // Faster specialization for bases <= 10 63 template<typename CHAR, int BASE> class BaseCharToDigit<CHAR, BASE, true> { 64 public: 65 static bool Convert(CHAR c, uint8_t* digit) { 66 if (c >= '0' && c < '0' + BASE) { 67 *digit = static_cast<uint8_t>(c - '0'); 68 return true; 69 } 70 return false; 71 } 72 }; 73 74 // Specialization for bases where 10 < base <= 36 75 template<typename CHAR, int BASE> class BaseCharToDigit<CHAR, BASE, false> { 76 public: 77 static bool Convert(CHAR c, uint8_t* digit) { 78 if (c >= '0' && c <= '9') { 79 *digit = c - '0'; 80 } else if (c >= 'a' && c < 'a' + BASE - 10) { 81 *digit = c - 'a' + 10; 82 } else if (c >= 'A' && c < 'A' + BASE - 10) { 83 *digit = c - 'A' + 10; 84 } else { 85 return false; 86 } 87 return true; 88 } 89 }; 90 91 template <int BASE, typename CHAR> 92 bool CharToDigit(CHAR c, uint8_t* digit) { 93 return BaseCharToDigit<CHAR, BASE, BASE <= 10>::Convert(c, digit); 94 } 95 96 // There is an IsUnicodeWhitespace for wchars defined in string_util.h, but it 97 // is locale independent, whereas the functions we are replacing were 98 // locale-dependent. TBD what is desired, but for the moment let's not 99 // introduce a change in behaviour. 100 template<typename CHAR> class WhitespaceHelper { 101 }; 102 103 template<> class WhitespaceHelper<char> { 104 public: 105 static bool Invoke(char c) { 106 return 0 != isspace(static_cast<unsigned char>(c)); 107 } 108 }; 109 110 template<> class WhitespaceHelper<char16> { 111 public: 112 static bool Invoke(char16 c) { 113 return 0 != iswspace(c); 114 } 115 }; 116 117 template<typename CHAR> bool LocalIsWhitespace(CHAR c) { 118 return WhitespaceHelper<CHAR>::Invoke(c); 119 } 120 121 // IteratorRangeToNumberTraits should provide: 122 // - a typedef for iterator_type, the iterator type used as input. 123 // - a typedef for value_type, the target numeric type. 124 // - static functions min, max (returning the minimum and maximum permitted 125 // values) 126 // - constant kBase, the base in which to interpret the input 127 template<typename IteratorRangeToNumberTraits> 128 class IteratorRangeToNumber { 129 public: 130 typedef IteratorRangeToNumberTraits traits; 131 typedef typename traits::iterator_type const_iterator; 132 typedef typename traits::value_type value_type; 133 134 // Generalized iterator-range-to-number conversion. 135 // 136 static bool Invoke(const_iterator begin, 137 const_iterator end, 138 value_type* output) { 139 bool valid = true; 140 141 while (begin != end && LocalIsWhitespace(*begin)) { 142 valid = false; 143 ++begin; 144 } 145 146 if (begin != end && *begin == '-') { 147 if (!std::numeric_limits<value_type>::is_signed) { 148 *output = 0; 149 valid = false; 150 } else if (!Negative::Invoke(begin + 1, end, output)) { 151 valid = false; 152 } 153 } else { 154 if (begin != end && *begin == '+') { 155 ++begin; 156 } 157 if (!Positive::Invoke(begin, end, output)) { 158 valid = false; 159 } 160 } 161 162 return valid; 163 } 164 165 private: 166 // Sign provides: 167 // - a static function, CheckBounds, that determines whether the next digit 168 // causes an overflow/underflow 169 // - a static function, Increment, that appends the next digit appropriately 170 // according to the sign of the number being parsed. 171 template<typename Sign> 172 class Base { 173 public: 174 static bool Invoke(const_iterator begin, const_iterator end, 175 typename traits::value_type* output) { 176 *output = 0; 177 178 if (begin == end) { 179 return false; 180 } 181 182 // Note: no performance difference was found when using template 183 // specialization to remove this check in bases other than 16 184 if (traits::kBase == 16 && end - begin > 2 && *begin == '0' && 185 (*(begin + 1) == 'x' || *(begin + 1) == 'X')) { 186 begin += 2; 187 } 188 189 for (const_iterator current = begin; current != end; ++current) { 190 uint8_t new_digit = 0; 191 192 if (!CharToDigit<traits::kBase>(*current, &new_digit)) { 193 return false; 194 } 195 196 if (current != begin) { 197 if (!Sign::CheckBounds(output, new_digit)) { 198 return false; 199 } 200 *output *= traits::kBase; 201 } 202 203 Sign::Increment(new_digit, output); 204 } 205 return true; 206 } 207 }; 208 209 class Positive : public Base<Positive> { 210 public: 211 static bool CheckBounds(value_type* output, uint8_t new_digit) { 212 if (*output > static_cast<value_type>(traits::max() / traits::kBase) || 213 (*output == static_cast<value_type>(traits::max() / traits::kBase) && 214 new_digit > traits::max() % traits::kBase)) { 215 *output = traits::max(); 216 return false; 217 } 218 return true; 219 } 220 static void Increment(uint8_t increment, value_type* output) { 221 *output += increment; 222 } 223 }; 224 225 class Negative : public Base<Negative> { 226 public: 227 static bool CheckBounds(value_type* output, uint8_t new_digit) { 228 if (*output < traits::min() / traits::kBase || 229 (*output == traits::min() / traits::kBase && 230 new_digit > 0 - traits::min() % traits::kBase)) { 231 *output = traits::min(); 232 return false; 233 } 234 return true; 235 } 236 static void Increment(uint8_t increment, value_type* output) { 237 *output -= increment; 238 } 239 }; 240 }; 241 242 template<typename ITERATOR, typename VALUE, int BASE> 243 class BaseIteratorRangeToNumberTraits { 244 public: 245 typedef ITERATOR iterator_type; 246 typedef VALUE value_type; 247 static value_type min() { 248 return std::numeric_limits<value_type>::min(); 249 } 250 static value_type max() { 251 return std::numeric_limits<value_type>::max(); 252 } 253 static const int kBase = BASE; 254 }; 255 256 template<typename ITERATOR> 257 class BaseHexIteratorRangeToIntTraits 258 : public BaseIteratorRangeToNumberTraits<ITERATOR, int, 16> { 259 }; 260 261 template <typename ITERATOR> 262 class BaseHexIteratorRangeToUIntTraits 263 : public BaseIteratorRangeToNumberTraits<ITERATOR, uint32_t, 16> {}; 264 265 template <typename ITERATOR> 266 class BaseHexIteratorRangeToInt64Traits 267 : public BaseIteratorRangeToNumberTraits<ITERATOR, int64_t, 16> {}; 268 269 template <typename ITERATOR> 270 class BaseHexIteratorRangeToUInt64Traits 271 : public BaseIteratorRangeToNumberTraits<ITERATOR, uint64_t, 16> {}; 272 273 typedef BaseHexIteratorRangeToIntTraits<StringPiece::const_iterator> 274 HexIteratorRangeToIntTraits; 275 276 typedef BaseHexIteratorRangeToUIntTraits<StringPiece::const_iterator> 277 HexIteratorRangeToUIntTraits; 278 279 typedef BaseHexIteratorRangeToInt64Traits<StringPiece::const_iterator> 280 HexIteratorRangeToInt64Traits; 281 282 typedef BaseHexIteratorRangeToUInt64Traits<StringPiece::const_iterator> 283 HexIteratorRangeToUInt64Traits; 284 285 template <typename STR> 286 bool HexStringToBytesT(const STR& input, std::vector<uint8_t>* output) { 287 DCHECK_EQ(output->size(), 0u); 288 size_t count = input.size(); 289 if (count == 0 || (count % 2) != 0) 290 return false; 291 for (uintptr_t i = 0; i < count / 2; ++i) { 292 uint8_t msb = 0; // most significant 4 bits 293 uint8_t lsb = 0; // least significant 4 bits 294 if (!CharToDigit<16>(input[i * 2], &msb) || 295 !CharToDigit<16>(input[i * 2 + 1], &lsb)) 296 return false; 297 output->push_back((msb << 4) | lsb); 298 } 299 return true; 300 } 301 302 template <typename VALUE, int BASE> 303 class StringPieceToNumberTraits 304 : public BaseIteratorRangeToNumberTraits<StringPiece::const_iterator, 305 VALUE, 306 BASE> { 307 }; 308 309 template <typename VALUE> 310 bool StringToIntImpl(const StringPiece& input, VALUE* output) { 311 return IteratorRangeToNumber<StringPieceToNumberTraits<VALUE, 10> >::Invoke( 312 input.begin(), input.end(), output); 313 } 314 315 template <typename VALUE, int BASE> 316 class StringPiece16ToNumberTraits 317 : public BaseIteratorRangeToNumberTraits<StringPiece16::const_iterator, 318 VALUE, 319 BASE> { 320 }; 321 322 template <typename VALUE> 323 bool String16ToIntImpl(const StringPiece16& input, VALUE* output) { 324 return IteratorRangeToNumber<StringPiece16ToNumberTraits<VALUE, 10> >::Invoke( 325 input.begin(), input.end(), output); 326 } 327 328 } // namespace 329 330 std::string IntToString(int value) { 331 return IntToStringT<std::string, int>::IntToString(value); 332 } 333 334 string16 IntToString16(int value) { 335 return IntToStringT<string16, int>::IntToString(value); 336 } 337 338 std::string UintToString(unsigned int value) { 339 return IntToStringT<std::string, unsigned int>::IntToString(value); 340 } 341 342 string16 UintToString16(unsigned int value) { 343 return IntToStringT<string16, unsigned int>::IntToString(value); 344 } 345 346 std::string Int64ToString(int64_t value) { 347 return IntToStringT<std::string, int64_t>::IntToString(value); 348 } 349 350 string16 Int64ToString16(int64_t value) { 351 return IntToStringT<string16, int64_t>::IntToString(value); 352 } 353 354 std::string Uint64ToString(uint64_t value) { 355 return IntToStringT<std::string, uint64_t>::IntToString(value); 356 } 357 358 string16 Uint64ToString16(uint64_t value) { 359 return IntToStringT<string16, uint64_t>::IntToString(value); 360 } 361 362 std::string SizeTToString(size_t value) { 363 return IntToStringT<std::string, size_t>::IntToString(value); 364 } 365 366 string16 SizeTToString16(size_t value) { 367 return IntToStringT<string16, size_t>::IntToString(value); 368 } 369 370 std::string DoubleToString(double value) { 371 auto ret = std::to_string(value); 372 // If this returned an integer, don't do anything. 373 if (ret.find('.') == std::string::npos) { 374 return ret; 375 } 376 // Otherwise, it has an annoying tendency to leave trailing zeros. 377 size_t len = ret.size(); 378 while (len >= 2 && ret[len - 1] == '0' && ret[len - 2] != '.') { 379 --len; 380 } 381 ret.erase(len); 382 return ret; 383 } 384 385 bool StringToInt(const StringPiece& input, int* output) { 386 return StringToIntImpl(input, output); 387 } 388 389 bool StringToInt(const StringPiece16& input, int* output) { 390 return String16ToIntImpl(input, output); 391 } 392 393 bool StringToUint(const StringPiece& input, unsigned* output) { 394 return StringToIntImpl(input, output); 395 } 396 397 bool StringToUint(const StringPiece16& input, unsigned* output) { 398 return String16ToIntImpl(input, output); 399 } 400 401 bool StringToInt64(const StringPiece& input, int64_t* output) { 402 return StringToIntImpl(input, output); 403 } 404 405 bool StringToInt64(const StringPiece16& input, int64_t* output) { 406 return String16ToIntImpl(input, output); 407 } 408 409 bool StringToUint64(const StringPiece& input, uint64_t* output) { 410 return StringToIntImpl(input, output); 411 } 412 413 bool StringToUint64(const StringPiece16& input, uint64_t* output) { 414 return String16ToIntImpl(input, output); 415 } 416 417 bool StringToSizeT(const StringPiece& input, size_t* output) { 418 return StringToIntImpl(input, output); 419 } 420 421 bool StringToSizeT(const StringPiece16& input, size_t* output) { 422 return String16ToIntImpl(input, output); 423 } 424 425 bool StringToDouble(const std::string& input, double* output) { 426 char* endptr = nullptr; 427 *output = strtod(input.c_str(), &endptr); 428 429 // Cases to return false: 430 // - If the input string is empty, there was nothing to parse. 431 // - If endptr does not point to the end of the string, there are either 432 // characters remaining in the string after a parsed number, or the string 433 // does not begin with a parseable number. endptr is compared to the 434 // expected end given the string's stated length to correctly catch cases 435 // where the string contains embedded NUL characters. 436 // - If the first character is a space, there was leading whitespace 437 return !input.empty() && 438 input.c_str() + input.length() == endptr && 439 !isspace(input[0]) && 440 *output != std::numeric_limits<double>::infinity() && 441 *output != -std::numeric_limits<double>::infinity(); 442 } 443 444 // Note: if you need to add String16ToDouble, first ask yourself if it's 445 // really necessary. If it is, probably the best implementation here is to 446 // convert to 8-bit and then use the 8-bit version. 447 448 // Note: if you need to add an iterator range version of StringToDouble, first 449 // ask yourself if it's really necessary. If it is, probably the best 450 // implementation here is to instantiate a string and use the string version. 451 452 std::string HexEncode(const void* bytes, size_t size) { 453 static const char kHexChars[] = "0123456789ABCDEF"; 454 455 // Each input byte creates two output hex characters. 456 std::string ret(size * 2, '\0'); 457 458 for (size_t i = 0; i < size; ++i) { 459 char b = reinterpret_cast<const char*>(bytes)[i]; 460 ret[(i * 2)] = kHexChars[(b >> 4) & 0xf]; 461 ret[(i * 2) + 1] = kHexChars[b & 0xf]; 462 } 463 return ret; 464 } 465 466 bool HexStringToInt(const StringPiece& input, int* output) { 467 return IteratorRangeToNumber<HexIteratorRangeToIntTraits>::Invoke( 468 input.begin(), input.end(), output); 469 } 470 471 bool HexStringToUInt(const StringPiece& input, uint32_t* output) { 472 return IteratorRangeToNumber<HexIteratorRangeToUIntTraits>::Invoke( 473 input.begin(), input.end(), output); 474 } 475 476 bool HexStringToInt64(const StringPiece& input, int64_t* output) { 477 return IteratorRangeToNumber<HexIteratorRangeToInt64Traits>::Invoke( 478 input.begin(), input.end(), output); 479 } 480 481 bool HexStringToUInt64(const StringPiece& input, uint64_t* output) { 482 return IteratorRangeToNumber<HexIteratorRangeToUInt64Traits>::Invoke( 483 input.begin(), input.end(), output); 484 } 485 486 bool HexStringToBytes(const std::string& input, std::vector<uint8_t>* output) { 487 return HexStringToBytesT(input, output); 488 } 489 490 } // namespace base 491