Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 1 | // Copyright 2006-2008 the V8 project authors. All rights reserved. |
| 2 | // Redistribution and use in source and binary forms, with or without |
| 3 | // modification, are permitted provided that the following conditions are |
| 4 | // met: |
| 5 | // |
| 6 | // * Redistributions of source code must retain the above copyright |
| 7 | // notice, this list of conditions and the following disclaimer. |
| 8 | // * Redistributions in binary form must reproduce the above |
| 9 | // copyright notice, this list of conditions and the following |
| 10 | // disclaimer in the documentation and/or other materials provided |
| 11 | // with the distribution. |
| 12 | // * Neither the name of Google Inc. nor the names of its |
| 13 | // contributors may be used to endorse or promote products derived |
| 14 | // from this software without specific prior written permission. |
| 15 | // |
| 16 | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 17 | // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 18 | // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 19 | // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
| 20 | // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| 21 | // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| 22 | // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| 23 | // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| 24 | // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| 25 | // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| 26 | // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 27 | |
| 28 | #include <stdarg.h> |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 29 | #include <limits.h> |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 30 | |
| 31 | #include "v8.h" |
| 32 | |
| 33 | #include "conversions-inl.h" |
Kristian Monsen | 25f6136 | 2010-05-21 11:50:48 +0100 | [diff] [blame] | 34 | #include "dtoa.h" |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 35 | #include "factory.h" |
| 36 | #include "scanner.h" |
| 37 | |
| 38 | namespace v8 { |
| 39 | namespace internal { |
| 40 | |
| 41 | int HexValue(uc32 c) { |
| 42 | if ('0' <= c && c <= '9') |
| 43 | return c - '0'; |
| 44 | if ('a' <= c && c <= 'f') |
| 45 | return c - 'a' + 10; |
| 46 | if ('A' <= c && c <= 'F') |
| 47 | return c - 'A' + 10; |
| 48 | return -1; |
| 49 | } |
| 50 | |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 51 | namespace { |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 52 | |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 53 | // C++-style iterator adaptor for StringInputBuffer |
| 54 | // (unlike C++ iterators the end-marker has different type). |
| 55 | class StringInputBufferIterator { |
| 56 | public: |
| 57 | class EndMarker {}; |
| 58 | |
| 59 | explicit StringInputBufferIterator(StringInputBuffer* buffer); |
| 60 | |
| 61 | int operator*() const; |
| 62 | void operator++(); |
| 63 | bool operator==(EndMarker const&) const { return end_; } |
| 64 | bool operator!=(EndMarker const& m) const { return !end_; } |
| 65 | |
| 66 | private: |
| 67 | StringInputBuffer* const buffer_; |
| 68 | int current_; |
| 69 | bool end_; |
| 70 | }; |
| 71 | |
| 72 | |
| 73 | StringInputBufferIterator::StringInputBufferIterator( |
| 74 | StringInputBuffer* buffer) : buffer_(buffer) { |
| 75 | ++(*this); |
| 76 | } |
| 77 | |
| 78 | int StringInputBufferIterator::operator*() const { |
| 79 | return current_; |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 80 | } |
| 81 | |
| 82 | |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 83 | void StringInputBufferIterator::operator++() { |
| 84 | end_ = !buffer_->has_more(); |
| 85 | if (!end_) { |
| 86 | current_ = buffer_->GetNext(); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 87 | } |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 88 | } |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 89 | } |
| 90 | |
| 91 | |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 92 | template <class Iterator, class EndMark> |
| 93 | static bool SubStringEquals(Iterator* current, |
| 94 | EndMark end, |
| 95 | const char* substring) { |
| 96 | ASSERT(**current == *substring); |
| 97 | for (substring++; *substring != '\0'; substring++) { |
| 98 | ++*current; |
| 99 | if (*current == end || **current != *substring) return false; |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 100 | } |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 101 | ++*current; |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 102 | return true; |
| 103 | } |
| 104 | |
| 105 | |
| 106 | extern "C" double gay_strtod(const char* s00, const char** se); |
| 107 | |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 108 | // Maximum number of significant digits in decimal representation. |
| 109 | // The longest possible double in decimal representation is |
| 110 | // (2^53 - 1) * 2 ^ -1074 that is (2 ^ 53 - 1) * 5 ^ 1074 / 10 ^ 1074 |
| 111 | // (768 digits). If we parse a number whose first digits are equal to a |
| 112 | // mean of 2 adjacent doubles (that could have up to 769 digits) the result |
| 113 | // must be rounded to the bigger one unless the tail consists of zeros, so |
| 114 | // we don't need to preserve all the digits. |
| 115 | const int kMaxSignificantDigits = 772; |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 116 | |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 117 | |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 118 | static const double JUNK_STRING_VALUE = OS::nan_value(); |
| 119 | |
| 120 | |
| 121 | // Returns true if a nonspace found and false if the end has reached. |
| 122 | template <class Iterator, class EndMark> |
| 123 | static inline bool AdvanceToNonspace(Iterator* current, EndMark end) { |
| 124 | while (*current != end) { |
| 125 | if (!Scanner::kIsWhiteSpace.get(**current)) return true; |
| 126 | ++*current; |
| 127 | } |
| 128 | return false; |
| 129 | } |
| 130 | |
| 131 | |
| 132 | static bool isDigit(int x, int radix) { |
| 133 | return (x >= '0' && x <= '9' && x < '0' + radix) |
| 134 | || (radix > 10 && x >= 'a' && x < 'a' + radix - 10) |
| 135 | || (radix > 10 && x >= 'A' && x < 'A' + radix - 10); |
| 136 | } |
| 137 | |
| 138 | |
| 139 | static double SignedZero(bool sign) { |
| 140 | return sign ? -0.0 : 0.0; |
| 141 | } |
| 142 | |
| 143 | |
| 144 | // Parsing integers with radix 2, 4, 8, 16, 32. Assumes current != end. |
| 145 | template <int radix_log_2, class Iterator, class EndMark> |
| 146 | static double InternalStringToIntDouble(Iterator current, |
| 147 | EndMark end, |
| 148 | bool sign, |
| 149 | bool allow_trailing_junk) { |
| 150 | ASSERT(current != end); |
| 151 | |
| 152 | // Skip leading 0s. |
| 153 | while (*current == '0') { |
| 154 | ++current; |
| 155 | if (current == end) return SignedZero(sign); |
| 156 | } |
| 157 | |
| 158 | int64_t number = 0; |
| 159 | int exponent = 0; |
| 160 | const int radix = (1 << radix_log_2); |
| 161 | |
| 162 | do { |
| 163 | int digit; |
| 164 | if (*current >= '0' && *current <= '9' && *current < '0' + radix) { |
| 165 | digit = static_cast<char>(*current) - '0'; |
| 166 | } else if (radix > 10 && *current >= 'a' && *current < 'a' + radix - 10) { |
| 167 | digit = static_cast<char>(*current) - 'a' + 10; |
| 168 | } else if (radix > 10 && *current >= 'A' && *current < 'A' + radix - 10) { |
| 169 | digit = static_cast<char>(*current) - 'A' + 10; |
| 170 | } else { |
| 171 | if (allow_trailing_junk || !AdvanceToNonspace(¤t, end)) { |
| 172 | break; |
| 173 | } else { |
| 174 | return JUNK_STRING_VALUE; |
| 175 | } |
| 176 | } |
| 177 | |
| 178 | number = number * radix + digit; |
| 179 | int overflow = static_cast<int>(number >> 53); |
| 180 | if (overflow != 0) { |
| 181 | // Overflow occurred. Need to determine which direction to round the |
| 182 | // result. |
| 183 | int overflow_bits_count = 1; |
| 184 | while (overflow > 1) { |
| 185 | overflow_bits_count++; |
| 186 | overflow >>= 1; |
| 187 | } |
| 188 | |
| 189 | int dropped_bits_mask = ((1 << overflow_bits_count) - 1); |
| 190 | int dropped_bits = static_cast<int>(number) & dropped_bits_mask; |
| 191 | number >>= overflow_bits_count; |
| 192 | exponent = overflow_bits_count; |
| 193 | |
| 194 | bool zero_tail = true; |
| 195 | while (true) { |
| 196 | ++current; |
| 197 | if (current == end || !isDigit(*current, radix)) break; |
| 198 | zero_tail = zero_tail && *current == '0'; |
| 199 | exponent += radix_log_2; |
| 200 | } |
| 201 | |
| 202 | if (!allow_trailing_junk && AdvanceToNonspace(¤t, end)) { |
| 203 | return JUNK_STRING_VALUE; |
| 204 | } |
| 205 | |
| 206 | int middle_value = (1 << (overflow_bits_count - 1)); |
| 207 | if (dropped_bits > middle_value) { |
| 208 | number++; // Rounding up. |
| 209 | } else if (dropped_bits == middle_value) { |
| 210 | // Rounding to even to consistency with decimals: half-way case rounds |
| 211 | // up if significant part is odd and down otherwise. |
| 212 | if ((number & 1) != 0 || !zero_tail) { |
| 213 | number++; // Rounding up. |
| 214 | } |
| 215 | } |
| 216 | |
| 217 | // Rounding up may cause overflow. |
| 218 | if ((number & ((int64_t)1 << 53)) != 0) { |
| 219 | exponent++; |
| 220 | number >>= 1; |
| 221 | } |
| 222 | break; |
| 223 | } |
| 224 | ++current; |
| 225 | } while (current != end); |
| 226 | |
| 227 | ASSERT(number < ((int64_t)1 << 53)); |
| 228 | ASSERT(static_cast<int64_t>(static_cast<double>(number)) == number); |
| 229 | |
| 230 | if (exponent == 0) { |
| 231 | if (sign) { |
| 232 | if (number == 0) return -0.0; |
| 233 | number = -number; |
| 234 | } |
| 235 | return static_cast<double>(number); |
| 236 | } |
| 237 | |
| 238 | ASSERT(number != 0); |
| 239 | // The double could be constructed faster from number (mantissa), exponent |
| 240 | // and sign. Assuming it's a rare case more simple code is used. |
| 241 | return static_cast<double>(sign ? -number : number) * pow(2.0, exponent); |
| 242 | } |
| 243 | |
| 244 | |
| 245 | template <class Iterator, class EndMark> |
| 246 | static double InternalStringToInt(Iterator current, EndMark end, int radix) { |
| 247 | const bool allow_trailing_junk = true; |
| 248 | const double empty_string_val = JUNK_STRING_VALUE; |
| 249 | |
| 250 | if (!AdvanceToNonspace(¤t, end)) return empty_string_val; |
| 251 | |
| 252 | bool sign = false; |
| 253 | bool leading_zero = false; |
| 254 | |
| 255 | if (*current == '+') { |
| 256 | // Ignore leading sign; skip following spaces. |
| 257 | ++current; |
| 258 | if (!AdvanceToNonspace(¤t, end)) return JUNK_STRING_VALUE; |
| 259 | } else if (*current == '-') { |
| 260 | ++current; |
| 261 | if (!AdvanceToNonspace(¤t, end)) return JUNK_STRING_VALUE; |
| 262 | sign = true; |
| 263 | } |
| 264 | |
| 265 | if (radix == 0) { |
| 266 | // Radix detection. |
| 267 | if (*current == '0') { |
| 268 | ++current; |
| 269 | if (current == end) return SignedZero(sign); |
| 270 | if (*current == 'x' || *current == 'X') { |
| 271 | radix = 16; |
| 272 | ++current; |
| 273 | if (current == end) return JUNK_STRING_VALUE; |
| 274 | } else { |
| 275 | radix = 8; |
| 276 | leading_zero = true; |
| 277 | } |
| 278 | } else { |
| 279 | radix = 10; |
| 280 | } |
| 281 | } else if (radix == 16) { |
| 282 | if (*current == '0') { |
| 283 | // Allow "0x" prefix. |
| 284 | ++current; |
| 285 | if (current == end) return SignedZero(sign); |
| 286 | if (*current == 'x' || *current == 'X') { |
| 287 | ++current; |
| 288 | if (current == end) return JUNK_STRING_VALUE; |
| 289 | } else { |
| 290 | leading_zero = true; |
| 291 | } |
| 292 | } |
| 293 | } |
| 294 | |
| 295 | if (radix < 2 || radix > 36) return JUNK_STRING_VALUE; |
| 296 | |
| 297 | // Skip leading zeros. |
| 298 | while (*current == '0') { |
| 299 | leading_zero = true; |
| 300 | ++current; |
| 301 | if (current == end) return SignedZero(sign); |
| 302 | } |
| 303 | |
| 304 | if (!leading_zero && !isDigit(*current, radix)) { |
| 305 | return JUNK_STRING_VALUE; |
| 306 | } |
| 307 | |
| 308 | if (IsPowerOf2(radix)) { |
| 309 | switch (radix) { |
| 310 | case 2: |
| 311 | return InternalStringToIntDouble<1>( |
| 312 | current, end, sign, allow_trailing_junk); |
| 313 | case 4: |
| 314 | return InternalStringToIntDouble<2>( |
| 315 | current, end, sign, allow_trailing_junk); |
| 316 | case 8: |
| 317 | return InternalStringToIntDouble<3>( |
| 318 | current, end, sign, allow_trailing_junk); |
| 319 | |
| 320 | case 16: |
| 321 | return InternalStringToIntDouble<4>( |
| 322 | current, end, sign, allow_trailing_junk); |
| 323 | |
| 324 | case 32: |
| 325 | return InternalStringToIntDouble<5>( |
| 326 | current, end, sign, allow_trailing_junk); |
| 327 | default: |
| 328 | UNREACHABLE(); |
| 329 | } |
| 330 | } |
| 331 | |
| 332 | if (radix == 10) { |
| 333 | // Parsing with strtod. |
| 334 | const int kMaxSignificantDigits = 309; // Doubles are less than 1.8e308. |
| 335 | // The buffer may contain up to kMaxSignificantDigits + 1 digits and a zero |
| 336 | // end. |
| 337 | const int kBufferSize = kMaxSignificantDigits + 2; |
| 338 | char buffer[kBufferSize]; |
| 339 | int buffer_pos = 0; |
| 340 | while (*current >= '0' && *current <= '9') { |
| 341 | if (buffer_pos <= kMaxSignificantDigits) { |
| 342 | // If the number has more than kMaxSignificantDigits it will be parsed |
| 343 | // as infinity. |
| 344 | ASSERT(buffer_pos < kBufferSize); |
| 345 | buffer[buffer_pos++] = static_cast<char>(*current); |
| 346 | } |
| 347 | ++current; |
| 348 | if (current == end) break; |
| 349 | } |
| 350 | |
| 351 | if (!allow_trailing_junk && AdvanceToNonspace(¤t, end)) { |
| 352 | return JUNK_STRING_VALUE; |
| 353 | } |
| 354 | |
| 355 | ASSERT(buffer_pos < kBufferSize); |
| 356 | buffer[buffer_pos++] = '\0'; |
| 357 | return sign ? -gay_strtod(buffer, NULL) : gay_strtod(buffer, NULL); |
| 358 | } |
| 359 | |
| 360 | // The following code causes accumulating rounding error for numbers greater |
| 361 | // than ~2^56. It's explicitly allowed in the spec: "if R is not 2, 4, 8, 10, |
| 362 | // 16, or 32, then mathInt may be an implementation-dependent approximation to |
| 363 | // the mathematical integer value" (15.1.2.2). |
| 364 | |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 365 | int lim_0 = '0' + (radix < 10 ? radix : 10); |
| 366 | int lim_a = 'a' + (radix - 10); |
| 367 | int lim_A = 'A' + (radix - 10); |
| 368 | |
| 369 | // NOTE: The code for computing the value may seem a bit complex at |
| 370 | // first glance. It is structured to use 32-bit multiply-and-add |
| 371 | // loops as long as possible to avoid loosing precision. |
| 372 | |
| 373 | double v = 0.0; |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 374 | bool done = false; |
| 375 | do { |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 376 | // Parse the longest part of the string starting at index j |
| 377 | // possible while keeping the multiplier, and thus the part |
| 378 | // itself, within 32 bits. |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 379 | unsigned int part = 0, multiplier = 1; |
| 380 | while (true) { |
| 381 | int d; |
| 382 | if (*current >= '0' && *current < lim_0) { |
| 383 | d = *current - '0'; |
| 384 | } else if (*current >= 'a' && *current < lim_a) { |
| 385 | d = *current - 'a' + 10; |
| 386 | } else if (*current >= 'A' && *current < lim_A) { |
| 387 | d = *current - 'A' + 10; |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 388 | } else { |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 389 | done = true; |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 390 | break; |
| 391 | } |
| 392 | |
| 393 | // Update the value of the part as long as the multiplier fits |
| 394 | // in 32 bits. When we can't guarantee that the next iteration |
| 395 | // will not overflow the multiplier, we stop parsing the part |
| 396 | // by leaving the loop. |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 397 | const unsigned int kMaximumMultiplier = 0xffffffffU / 36; |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 398 | uint32_t m = multiplier * radix; |
| 399 | if (m > kMaximumMultiplier) break; |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 400 | part = part * radix + d; |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 401 | multiplier = m; |
| 402 | ASSERT(multiplier > part); |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 403 | |
| 404 | ++current; |
| 405 | if (current == end) { |
| 406 | done = true; |
| 407 | break; |
| 408 | } |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 409 | } |
| 410 | |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 411 | // Update the value and skip the part in the string. |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 412 | v = v * multiplier + part; |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 413 | } while (!done); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 414 | |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 415 | if (!allow_trailing_junk && AdvanceToNonspace(¤t, end)) { |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 416 | return JUNK_STRING_VALUE; |
| 417 | } |
| 418 | |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 419 | return sign ? -v : v; |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 420 | } |
| 421 | |
| 422 | |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 423 | // Converts a string to a double value. Assumes the Iterator supports |
| 424 | // the following operations: |
| 425 | // 1. current == end (other ops are not allowed), current != end. |
| 426 | // 2. *current - gets the current character in the sequence. |
| 427 | // 3. ++current (advances the position). |
| 428 | template <class Iterator, class EndMark> |
| 429 | static double InternalStringToDouble(Iterator current, |
| 430 | EndMark end, |
| 431 | int flags, |
| 432 | double empty_string_val) { |
| 433 | // To make sure that iterator dereferencing is valid the following |
| 434 | // convention is used: |
| 435 | // 1. Each '++current' statement is followed by check for equality to 'end'. |
| 436 | // 2. If AdvanceToNonspace returned false then current == end. |
| 437 | // 3. If 'current' becomes be equal to 'end' the function returns or goes to |
| 438 | // 'parsing_done'. |
| 439 | // 4. 'current' is not dereferenced after the 'parsing_done' label. |
| 440 | // 5. Code before 'parsing_done' may rely on 'current != end'. |
| 441 | if (!AdvanceToNonspace(¤t, end)) return empty_string_val; |
| 442 | |
| 443 | const bool allow_trailing_junk = (flags & ALLOW_TRAILING_JUNK) != 0; |
| 444 | |
| 445 | // The longest form of simplified number is: "-<significant digits>'.1eXXX\0". |
| 446 | const int kBufferSize = kMaxSignificantDigits + 10; |
| 447 | char buffer[kBufferSize]; // NOLINT: size is known at compile time. |
| 448 | int buffer_pos = 0; |
| 449 | |
| 450 | // Exponent will be adjusted if insignificant digits of the integer part |
| 451 | // or insignificant leading zeros of the fractional part are dropped. |
| 452 | int exponent = 0; |
| 453 | int significant_digits = 0; |
| 454 | int insignificant_digits = 0; |
| 455 | bool nonzero_digit_dropped = false; |
| 456 | bool fractional_part = false; |
| 457 | |
| 458 | bool sign = false; |
| 459 | |
| 460 | if (*current == '+') { |
| 461 | // Ignore leading sign; skip following spaces. |
| 462 | ++current; |
| 463 | if (!AdvanceToNonspace(¤t, end)) return JUNK_STRING_VALUE; |
| 464 | } else if (*current == '-') { |
| 465 | buffer[buffer_pos++] = '-'; |
| 466 | ++current; |
| 467 | if (!AdvanceToNonspace(¤t, end)) return JUNK_STRING_VALUE; |
| 468 | sign = true; |
| 469 | } |
| 470 | |
| 471 | static const char kInfinitySymbol[] = "Infinity"; |
| 472 | if (*current == kInfinitySymbol[0]) { |
| 473 | if (!SubStringEquals(¤t, end, kInfinitySymbol)) { |
| 474 | return JUNK_STRING_VALUE; |
| 475 | } |
| 476 | |
| 477 | if (!allow_trailing_junk && AdvanceToNonspace(¤t, end)) { |
| 478 | return JUNK_STRING_VALUE; |
| 479 | } |
| 480 | |
| 481 | ASSERT(buffer_pos == 0 || buffer[0] == '-'); |
| 482 | return buffer_pos > 0 ? -V8_INFINITY : V8_INFINITY; |
| 483 | } |
| 484 | |
| 485 | bool leading_zero = false; |
| 486 | if (*current == '0') { |
| 487 | ++current; |
| 488 | if (current == end) return SignedZero(sign); |
| 489 | |
| 490 | leading_zero = true; |
| 491 | |
| 492 | // It could be hexadecimal value. |
| 493 | if ((flags & ALLOW_HEX) && (*current == 'x' || *current == 'X')) { |
| 494 | ++current; |
| 495 | if (current == end || !isDigit(*current, 16)) { |
| 496 | return JUNK_STRING_VALUE; // "0x". |
| 497 | } |
| 498 | |
| 499 | bool sign = (buffer_pos > 0 && buffer[0] == '-'); |
| 500 | return InternalStringToIntDouble<4>(current, |
| 501 | end, |
| 502 | sign, |
| 503 | allow_trailing_junk); |
| 504 | } |
| 505 | |
| 506 | // Ignore leading zeros in the integer part. |
| 507 | while (*current == '0') { |
| 508 | ++current; |
| 509 | if (current == end) return SignedZero(sign); |
| 510 | } |
| 511 | } |
| 512 | |
| 513 | bool octal = leading_zero && (flags & ALLOW_OCTALS) != 0; |
| 514 | |
| 515 | // Copy significant digits of the integer part (if any) to the buffer. |
| 516 | while (*current >= '0' && *current <= '9') { |
| 517 | if (significant_digits < kMaxSignificantDigits) { |
| 518 | ASSERT(buffer_pos < kBufferSize); |
| 519 | buffer[buffer_pos++] = static_cast<char>(*current); |
| 520 | significant_digits++; |
| 521 | // Will later check if it's an octal in the buffer. |
| 522 | } else { |
| 523 | insignificant_digits++; // Move the digit into the exponential part. |
| 524 | nonzero_digit_dropped = nonzero_digit_dropped || *current != '0'; |
| 525 | } |
| 526 | octal = octal && *current < '8'; |
| 527 | ++current; |
| 528 | if (current == end) goto parsing_done; |
| 529 | } |
| 530 | |
| 531 | if (significant_digits == 0) { |
| 532 | octal = false; |
| 533 | } |
| 534 | |
| 535 | if (*current == '.') { |
| 536 | ++current; |
| 537 | if (current == end) { |
| 538 | if (significant_digits == 0 && !leading_zero) { |
| 539 | return JUNK_STRING_VALUE; |
| 540 | } else { |
| 541 | goto parsing_done; |
| 542 | } |
| 543 | } |
| 544 | |
| 545 | if (significant_digits == 0) { |
| 546 | // octal = false; |
| 547 | // Integer part consists of 0 or is absent. Significant digits start after |
| 548 | // leading zeros (if any). |
| 549 | while (*current == '0') { |
| 550 | ++current; |
| 551 | if (current == end) return SignedZero(sign); |
| 552 | exponent--; // Move this 0 into the exponent. |
| 553 | } |
| 554 | } |
| 555 | |
| 556 | ASSERT(buffer_pos < kBufferSize); |
| 557 | buffer[buffer_pos++] = '.'; |
| 558 | fractional_part = true; |
| 559 | |
| 560 | // There is the fractional part. |
| 561 | while (*current >= '0' && *current <= '9') { |
| 562 | if (significant_digits < kMaxSignificantDigits) { |
| 563 | ASSERT(buffer_pos < kBufferSize); |
| 564 | buffer[buffer_pos++] = static_cast<char>(*current); |
| 565 | significant_digits++; |
| 566 | } else { |
| 567 | // Ignore insignificant digits in the fractional part. |
| 568 | nonzero_digit_dropped = nonzero_digit_dropped || *current != '0'; |
| 569 | } |
| 570 | ++current; |
| 571 | if (current == end) goto parsing_done; |
| 572 | } |
| 573 | } |
| 574 | |
| 575 | if (!leading_zero && exponent == 0 && significant_digits == 0) { |
| 576 | // If leading_zeros is true then the string contains zeros. |
| 577 | // If exponent < 0 then string was [+-]\.0*... |
| 578 | // If significant_digits != 0 the string is not equal to 0. |
| 579 | // Otherwise there are no digits in the string. |
| 580 | return JUNK_STRING_VALUE; |
| 581 | } |
| 582 | |
| 583 | // Parse exponential part. |
| 584 | if (*current == 'e' || *current == 'E') { |
| 585 | if (octal) return JUNK_STRING_VALUE; |
| 586 | ++current; |
| 587 | if (current == end) { |
| 588 | if (allow_trailing_junk) { |
| 589 | goto parsing_done; |
| 590 | } else { |
| 591 | return JUNK_STRING_VALUE; |
| 592 | } |
| 593 | } |
| 594 | char sign = '+'; |
| 595 | if (*current == '+' || *current == '-') { |
| 596 | sign = static_cast<char>(*current); |
| 597 | ++current; |
| 598 | if (current == end) { |
| 599 | if (allow_trailing_junk) { |
| 600 | goto parsing_done; |
| 601 | } else { |
| 602 | return JUNK_STRING_VALUE; |
| 603 | } |
| 604 | } |
| 605 | } |
| 606 | |
| 607 | if (current == end || *current < '0' || *current > '9') { |
| 608 | if (allow_trailing_junk) { |
| 609 | goto parsing_done; |
| 610 | } else { |
| 611 | return JUNK_STRING_VALUE; |
| 612 | } |
| 613 | } |
| 614 | |
| 615 | const int max_exponent = INT_MAX / 2; |
| 616 | ASSERT(-max_exponent / 2 <= exponent && exponent <= max_exponent / 2); |
| 617 | int num = 0; |
| 618 | do { |
| 619 | // Check overflow. |
| 620 | int digit = *current - '0'; |
| 621 | if (num >= max_exponent / 10 |
| 622 | && !(num == max_exponent / 10 && digit <= max_exponent % 10)) { |
| 623 | num = max_exponent; |
| 624 | } else { |
| 625 | num = num * 10 + digit; |
| 626 | } |
| 627 | ++current; |
| 628 | } while (current != end && *current >= '0' && *current <= '9'); |
| 629 | |
| 630 | exponent += (sign == '-' ? -num : num); |
| 631 | } |
| 632 | |
| 633 | if (!allow_trailing_junk && AdvanceToNonspace(¤t, end)) { |
| 634 | return JUNK_STRING_VALUE; |
| 635 | } |
| 636 | |
| 637 | parsing_done: |
| 638 | exponent += insignificant_digits; |
| 639 | |
| 640 | if (octal) { |
| 641 | bool sign = buffer[0] == '-'; |
| 642 | int start_pos = (sign ? 1 : 0); |
| 643 | |
| 644 | return InternalStringToIntDouble<3>(buffer + start_pos, |
| 645 | buffer + buffer_pos, |
| 646 | sign, |
| 647 | allow_trailing_junk); |
| 648 | } |
| 649 | |
| 650 | if (nonzero_digit_dropped) { |
| 651 | if (insignificant_digits) buffer[buffer_pos++] = '.'; |
| 652 | buffer[buffer_pos++] = '1'; |
| 653 | } |
| 654 | |
| 655 | // If the number has no more than kMaxDigitsInInt digits and doesn't have |
| 656 | // fractional part it could be parsed faster (without checks for |
| 657 | // spaces, overflow, etc.). |
| 658 | const int kMaxDigitsInInt = 9 * sizeof(int) / 4; // NOLINT |
| 659 | |
| 660 | if (exponent != 0) { |
| 661 | ASSERT(buffer_pos < kBufferSize); |
| 662 | buffer[buffer_pos++] = 'e'; |
| 663 | if (exponent < 0) { |
| 664 | ASSERT(buffer_pos < kBufferSize); |
| 665 | buffer[buffer_pos++] = '-'; |
| 666 | exponent = -exponent; |
| 667 | } |
| 668 | if (exponent > 999) exponent = 999; // Result will be Infinity or 0 or -0. |
| 669 | |
| 670 | const int exp_digits = 3; |
| 671 | for (int i = 0; i < exp_digits; i++) { |
| 672 | buffer[buffer_pos + exp_digits - 1 - i] = '0' + exponent % 10; |
| 673 | exponent /= 10; |
| 674 | } |
| 675 | ASSERT(exponent == 0); |
| 676 | buffer_pos += exp_digits; |
| 677 | } else if (!fractional_part && significant_digits <= kMaxDigitsInInt) { |
| 678 | if (significant_digits == 0) return SignedZero(sign); |
| 679 | ASSERT(buffer_pos > 0); |
| 680 | int num = 0; |
| 681 | int start_pos = (buffer[0] == '-' ? 1 : 0); |
| 682 | for (int i = start_pos; i < buffer_pos; i++) { |
| 683 | ASSERT(buffer[i] >= '0' && buffer[i] <= '9'); |
| 684 | num = 10 * num + (buffer[i] - '0'); |
| 685 | } |
| 686 | return static_cast<double>(start_pos == 0 ? num : -num); |
| 687 | } |
| 688 | |
| 689 | ASSERT(buffer_pos < kBufferSize); |
| 690 | buffer[buffer_pos] = '\0'; |
| 691 | |
| 692 | return gay_strtod(buffer, NULL); |
| 693 | } |
| 694 | |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 695 | double StringToDouble(String* str, int flags, double empty_string_val) { |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 696 | StringShape shape(str); |
| 697 | if (shape.IsSequentialAscii()) { |
| 698 | const char* begin = SeqAsciiString::cast(str)->GetChars(); |
| 699 | const char* end = begin + str->length(); |
| 700 | return InternalStringToDouble(begin, end, flags, empty_string_val); |
| 701 | } else if (shape.IsSequentialTwoByte()) { |
| 702 | const uc16* begin = SeqTwoByteString::cast(str)->GetChars(); |
| 703 | const uc16* end = begin + str->length(); |
| 704 | return InternalStringToDouble(begin, end, flags, empty_string_val); |
| 705 | } else { |
| 706 | StringInputBuffer buffer(str); |
| 707 | return InternalStringToDouble(StringInputBufferIterator(&buffer), |
| 708 | StringInputBufferIterator::EndMarker(), |
| 709 | flags, |
| 710 | empty_string_val); |
| 711 | } |
| 712 | } |
| 713 | |
| 714 | |
| 715 | double StringToInt(String* str, int radix) { |
| 716 | StringShape shape(str); |
| 717 | if (shape.IsSequentialAscii()) { |
| 718 | const char* begin = SeqAsciiString::cast(str)->GetChars(); |
| 719 | const char* end = begin + str->length(); |
| 720 | return InternalStringToInt(begin, end, radix); |
| 721 | } else if (shape.IsSequentialTwoByte()) { |
| 722 | const uc16* begin = SeqTwoByteString::cast(str)->GetChars(); |
| 723 | const uc16* end = begin + str->length(); |
| 724 | return InternalStringToInt(begin, end, radix); |
| 725 | } else { |
| 726 | StringInputBuffer buffer(str); |
| 727 | return InternalStringToInt(StringInputBufferIterator(&buffer), |
| 728 | StringInputBufferIterator::EndMarker(), |
| 729 | radix); |
| 730 | } |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 731 | } |
| 732 | |
| 733 | |
| 734 | double StringToDouble(const char* str, int flags, double empty_string_val) { |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 735 | const char* end = str + StrLength(str); |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 736 | return InternalStringToDouble(str, end, flags, empty_string_val); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 737 | } |
| 738 | |
| 739 | |
Kristian Monsen | 80d68ea | 2010-09-08 11:05:35 +0100 | [diff] [blame^] | 740 | double StringToDouble(Vector<const char> str, |
| 741 | int flags, |
| 742 | double empty_string_val) { |
| 743 | const char* end = str.start() + str.length(); |
| 744 | return InternalStringToDouble(str.start(), end, flags, empty_string_val); |
| 745 | } |
| 746 | |
| 747 | |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 748 | extern "C" char* dtoa(double d, int mode, int ndigits, |
| 749 | int* decpt, int* sign, char** rve); |
| 750 | |
| 751 | extern "C" void freedtoa(char* s); |
| 752 | |
| 753 | const char* DoubleToCString(double v, Vector<char> buffer) { |
| 754 | StringBuilder builder(buffer.start(), buffer.length()); |
| 755 | |
| 756 | switch (fpclassify(v)) { |
| 757 | case FP_NAN: |
| 758 | builder.AddString("NaN"); |
| 759 | break; |
| 760 | |
| 761 | case FP_INFINITE: |
| 762 | if (v < 0.0) { |
| 763 | builder.AddString("-Infinity"); |
| 764 | } else { |
| 765 | builder.AddString("Infinity"); |
| 766 | } |
| 767 | break; |
| 768 | |
| 769 | case FP_ZERO: |
| 770 | builder.AddCharacter('0'); |
| 771 | break; |
| 772 | |
| 773 | default: { |
| 774 | int decimal_point; |
| 775 | int sign; |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 776 | char* decimal_rep; |
| 777 | bool used_gay_dtoa = false; |
Kristian Monsen | 25f6136 | 2010-05-21 11:50:48 +0100 | [diff] [blame] | 778 | const int kV8DtoaBufferCapacity = kBase10MaximalLength + 1; |
| 779 | char v8_dtoa_buffer[kV8DtoaBufferCapacity]; |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 780 | int length; |
Kristian Monsen | 25f6136 | 2010-05-21 11:50:48 +0100 | [diff] [blame] | 781 | |
| 782 | if (DoubleToAscii(v, DTOA_SHORTEST, 0, |
| 783 | Vector<char>(v8_dtoa_buffer, kV8DtoaBufferCapacity), |
| 784 | &sign, &length, &decimal_point)) { |
| 785 | decimal_rep = v8_dtoa_buffer; |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 786 | } else { |
| 787 | decimal_rep = dtoa(v, 0, 0, &decimal_point, &sign, NULL); |
| 788 | used_gay_dtoa = true; |
| 789 | length = StrLength(decimal_rep); |
| 790 | } |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 791 | |
| 792 | if (sign) builder.AddCharacter('-'); |
| 793 | |
| 794 | if (length <= decimal_point && decimal_point <= 21) { |
| 795 | // ECMA-262 section 9.8.1 step 6. |
| 796 | builder.AddString(decimal_rep); |
| 797 | builder.AddPadding('0', decimal_point - length); |
| 798 | |
| 799 | } else if (0 < decimal_point && decimal_point <= 21) { |
| 800 | // ECMA-262 section 9.8.1 step 7. |
| 801 | builder.AddSubstring(decimal_rep, decimal_point); |
| 802 | builder.AddCharacter('.'); |
| 803 | builder.AddString(decimal_rep + decimal_point); |
| 804 | |
| 805 | } else if (decimal_point <= 0 && decimal_point > -6) { |
| 806 | // ECMA-262 section 9.8.1 step 8. |
| 807 | builder.AddString("0."); |
| 808 | builder.AddPadding('0', -decimal_point); |
| 809 | builder.AddString(decimal_rep); |
| 810 | |
| 811 | } else { |
| 812 | // ECMA-262 section 9.8.1 step 9 and 10 combined. |
| 813 | builder.AddCharacter(decimal_rep[0]); |
| 814 | if (length != 1) { |
| 815 | builder.AddCharacter('.'); |
| 816 | builder.AddString(decimal_rep + 1); |
| 817 | } |
| 818 | builder.AddCharacter('e'); |
| 819 | builder.AddCharacter((decimal_point >= 0) ? '+' : '-'); |
| 820 | int exponent = decimal_point - 1; |
| 821 | if (exponent < 0) exponent = -exponent; |
| 822 | builder.AddFormatted("%d", exponent); |
| 823 | } |
| 824 | |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 825 | if (used_gay_dtoa) freedtoa(decimal_rep); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 826 | } |
| 827 | } |
| 828 | return builder.Finalize(); |
| 829 | } |
| 830 | |
| 831 | |
| 832 | const char* IntToCString(int n, Vector<char> buffer) { |
| 833 | bool negative = false; |
| 834 | if (n < 0) { |
| 835 | // We must not negate the most negative int. |
| 836 | if (n == kMinInt) return DoubleToCString(n, buffer); |
| 837 | negative = true; |
| 838 | n = -n; |
| 839 | } |
| 840 | // Build the string backwards from the least significant digit. |
| 841 | int i = buffer.length(); |
| 842 | buffer[--i] = '\0'; |
| 843 | do { |
| 844 | buffer[--i] = '0' + (n % 10); |
| 845 | n /= 10; |
| 846 | } while (n); |
| 847 | if (negative) buffer[--i] = '-'; |
| 848 | return buffer.start() + i; |
| 849 | } |
| 850 | |
| 851 | |
| 852 | char* DoubleToFixedCString(double value, int f) { |
Kristian Monsen | 25f6136 | 2010-05-21 11:50:48 +0100 | [diff] [blame] | 853 | const int kMaxDigitsBeforePoint = 20; |
| 854 | const double kFirstNonFixed = 1e21; |
| 855 | const int kMaxDigitsAfterPoint = 20; |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 856 | ASSERT(f >= 0); |
Kristian Monsen | 25f6136 | 2010-05-21 11:50:48 +0100 | [diff] [blame] | 857 | ASSERT(f <= kMaxDigitsAfterPoint); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 858 | |
| 859 | bool negative = false; |
| 860 | double abs_value = value; |
| 861 | if (value < 0) { |
| 862 | abs_value = -value; |
| 863 | negative = true; |
| 864 | } |
| 865 | |
Kristian Monsen | 25f6136 | 2010-05-21 11:50:48 +0100 | [diff] [blame] | 866 | // If abs_value has more than kMaxDigitsBeforePoint digits before the point |
| 867 | // use the non-fixed conversion routine. |
| 868 | if (abs_value >= kFirstNonFixed) { |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 869 | char arr[100]; |
| 870 | Vector<char> buffer(arr, ARRAY_SIZE(arr)); |
| 871 | return StrDup(DoubleToCString(value, buffer)); |
| 872 | } |
| 873 | |
| 874 | // Find a sufficiently precise decimal representation of n. |
| 875 | int decimal_point; |
| 876 | int sign; |
Kristian Monsen | 25f6136 | 2010-05-21 11:50:48 +0100 | [diff] [blame] | 877 | // Add space for the '.' and the '\0' byte. |
| 878 | const int kDecimalRepCapacity = |
| 879 | kMaxDigitsBeforePoint + kMaxDigitsAfterPoint + 2; |
| 880 | char decimal_rep[kDecimalRepCapacity]; |
| 881 | int decimal_rep_length; |
| 882 | bool status = DoubleToAscii(value, DTOA_FIXED, f, |
| 883 | Vector<char>(decimal_rep, kDecimalRepCapacity), |
| 884 | &sign, &decimal_rep_length, &decimal_point); |
| 885 | USE(status); |
| 886 | ASSERT(status); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 887 | |
| 888 | // Create a representation that is padded with zeros if needed. |
| 889 | int zero_prefix_length = 0; |
| 890 | int zero_postfix_length = 0; |
| 891 | |
| 892 | if (decimal_point <= 0) { |
| 893 | zero_prefix_length = -decimal_point + 1; |
| 894 | decimal_point = 1; |
| 895 | } |
| 896 | |
| 897 | if (zero_prefix_length + decimal_rep_length < decimal_point + f) { |
| 898 | zero_postfix_length = decimal_point + f - decimal_rep_length - |
| 899 | zero_prefix_length; |
| 900 | } |
| 901 | |
| 902 | unsigned rep_length = |
| 903 | zero_prefix_length + decimal_rep_length + zero_postfix_length; |
| 904 | StringBuilder rep_builder(rep_length + 1); |
| 905 | rep_builder.AddPadding('0', zero_prefix_length); |
| 906 | rep_builder.AddString(decimal_rep); |
| 907 | rep_builder.AddPadding('0', zero_postfix_length); |
| 908 | char* rep = rep_builder.Finalize(); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 909 | |
| 910 | // Create the result string by appending a minus and putting in a |
| 911 | // decimal point if needed. |
| 912 | unsigned result_size = decimal_point + f + 2; |
| 913 | StringBuilder builder(result_size + 1); |
| 914 | if (negative) builder.AddCharacter('-'); |
| 915 | builder.AddSubstring(rep, decimal_point); |
| 916 | if (f > 0) { |
| 917 | builder.AddCharacter('.'); |
| 918 | builder.AddSubstring(rep + decimal_point, f); |
| 919 | } |
| 920 | DeleteArray(rep); |
| 921 | return builder.Finalize(); |
| 922 | } |
| 923 | |
| 924 | |
| 925 | static char* CreateExponentialRepresentation(char* decimal_rep, |
| 926 | int exponent, |
| 927 | bool negative, |
| 928 | int significant_digits) { |
| 929 | bool negative_exponent = false; |
| 930 | if (exponent < 0) { |
| 931 | negative_exponent = true; |
| 932 | exponent = -exponent; |
| 933 | } |
| 934 | |
| 935 | // Leave room in the result for appending a minus, for a period, the |
| 936 | // letter 'e', a minus or a plus depending on the exponent, and a |
| 937 | // three digit exponent. |
| 938 | unsigned result_size = significant_digits + 7; |
| 939 | StringBuilder builder(result_size + 1); |
| 940 | |
| 941 | if (negative) builder.AddCharacter('-'); |
| 942 | builder.AddCharacter(decimal_rep[0]); |
| 943 | if (significant_digits != 1) { |
| 944 | builder.AddCharacter('.'); |
| 945 | builder.AddString(decimal_rep + 1); |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 946 | int rep_length = StrLength(decimal_rep); |
| 947 | builder.AddPadding('0', significant_digits - rep_length); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 948 | } |
| 949 | |
| 950 | builder.AddCharacter('e'); |
| 951 | builder.AddCharacter(negative_exponent ? '-' : '+'); |
| 952 | builder.AddFormatted("%d", exponent); |
| 953 | return builder.Finalize(); |
| 954 | } |
| 955 | |
| 956 | |
| 957 | |
| 958 | char* DoubleToExponentialCString(double value, int f) { |
| 959 | // f might be -1 to signal that f was undefined in JavaScript. |
| 960 | ASSERT(f >= -1 && f <= 20); |
| 961 | |
| 962 | bool negative = false; |
| 963 | if (value < 0) { |
| 964 | value = -value; |
| 965 | negative = true; |
| 966 | } |
| 967 | |
| 968 | // Find a sufficiently precise decimal representation of n. |
| 969 | int decimal_point; |
| 970 | int sign; |
| 971 | char* decimal_rep = NULL; |
| 972 | if (f == -1) { |
| 973 | decimal_rep = dtoa(value, 0, 0, &decimal_point, &sign, NULL); |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 974 | f = StrLength(decimal_rep) - 1; |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 975 | } else { |
| 976 | decimal_rep = dtoa(value, 2, f + 1, &decimal_point, &sign, NULL); |
| 977 | } |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 978 | int decimal_rep_length = StrLength(decimal_rep); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 979 | ASSERT(decimal_rep_length > 0); |
| 980 | ASSERT(decimal_rep_length <= f + 1); |
| 981 | USE(decimal_rep_length); |
| 982 | |
| 983 | int exponent = decimal_point - 1; |
| 984 | char* result = |
| 985 | CreateExponentialRepresentation(decimal_rep, exponent, negative, f+1); |
| 986 | |
| 987 | freedtoa(decimal_rep); |
| 988 | |
| 989 | return result; |
| 990 | } |
| 991 | |
| 992 | |
| 993 | char* DoubleToPrecisionCString(double value, int p) { |
| 994 | ASSERT(p >= 1 && p <= 21); |
| 995 | |
| 996 | bool negative = false; |
| 997 | if (value < 0) { |
| 998 | value = -value; |
| 999 | negative = true; |
| 1000 | } |
| 1001 | |
| 1002 | // Find a sufficiently precise decimal representation of n. |
| 1003 | int decimal_point; |
| 1004 | int sign; |
| 1005 | char* decimal_rep = dtoa(value, 2, p, &decimal_point, &sign, NULL); |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 1006 | int decimal_rep_length = StrLength(decimal_rep); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 1007 | ASSERT(decimal_rep_length <= p); |
| 1008 | |
| 1009 | int exponent = decimal_point - 1; |
| 1010 | |
| 1011 | char* result = NULL; |
| 1012 | |
| 1013 | if (exponent < -6 || exponent >= p) { |
| 1014 | result = |
| 1015 | CreateExponentialRepresentation(decimal_rep, exponent, negative, p); |
| 1016 | } else { |
| 1017 | // Use fixed notation. |
| 1018 | // |
| 1019 | // Leave room in the result for appending a minus, a period and in |
| 1020 | // the case where decimal_point is not positive for a zero in |
| 1021 | // front of the period. |
| 1022 | unsigned result_size = (decimal_point <= 0) |
| 1023 | ? -decimal_point + p + 3 |
| 1024 | : p + 2; |
| 1025 | StringBuilder builder(result_size + 1); |
| 1026 | if (negative) builder.AddCharacter('-'); |
| 1027 | if (decimal_point <= 0) { |
| 1028 | builder.AddString("0."); |
| 1029 | builder.AddPadding('0', -decimal_point); |
| 1030 | builder.AddString(decimal_rep); |
| 1031 | builder.AddPadding('0', p - decimal_rep_length); |
| 1032 | } else { |
| 1033 | const int m = Min(decimal_rep_length, decimal_point); |
| 1034 | builder.AddSubstring(decimal_rep, m); |
| 1035 | builder.AddPadding('0', decimal_point - decimal_rep_length); |
| 1036 | if (decimal_point < p) { |
| 1037 | builder.AddCharacter('.'); |
| 1038 | const int extra = negative ? 2 : 1; |
| 1039 | if (decimal_rep_length > decimal_point) { |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 1040 | const int len = StrLength(decimal_rep + decimal_point); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 1041 | const int n = Min(len, p - (builder.position() - extra)); |
| 1042 | builder.AddSubstring(decimal_rep + decimal_point, n); |
| 1043 | } |
| 1044 | builder.AddPadding('0', extra + (p - builder.position())); |
| 1045 | } |
| 1046 | } |
| 1047 | result = builder.Finalize(); |
| 1048 | } |
| 1049 | |
| 1050 | freedtoa(decimal_rep); |
| 1051 | return result; |
| 1052 | } |
| 1053 | |
| 1054 | |
| 1055 | char* DoubleToRadixCString(double value, int radix) { |
| 1056 | ASSERT(radix >= 2 && radix <= 36); |
| 1057 | |
| 1058 | // Character array used for conversion. |
| 1059 | static const char chars[] = "0123456789abcdefghijklmnopqrstuvwxyz"; |
| 1060 | |
| 1061 | // Buffer for the integer part of the result. 1024 chars is enough |
| 1062 | // for max integer value in radix 2. We need room for a sign too. |
| 1063 | static const int kBufferSize = 1100; |
| 1064 | char integer_buffer[kBufferSize]; |
| 1065 | integer_buffer[kBufferSize - 1] = '\0'; |
| 1066 | |
| 1067 | // Buffer for the decimal part of the result. We only generate up |
| 1068 | // to kBufferSize - 1 chars for the decimal part. |
| 1069 | char decimal_buffer[kBufferSize]; |
| 1070 | decimal_buffer[kBufferSize - 1] = '\0'; |
| 1071 | |
| 1072 | // Make sure the value is positive. |
| 1073 | bool is_negative = value < 0.0; |
| 1074 | if (is_negative) value = -value; |
| 1075 | |
| 1076 | // Get the integer part and the decimal part. |
| 1077 | double integer_part = floor(value); |
| 1078 | double decimal_part = value - integer_part; |
| 1079 | |
| 1080 | // Convert the integer part starting from the back. Always generate |
| 1081 | // at least one digit. |
| 1082 | int integer_pos = kBufferSize - 2; |
| 1083 | do { |
| 1084 | integer_buffer[integer_pos--] = |
Steve Block | 3ce2e20 | 2009-11-05 08:53:23 +0000 | [diff] [blame] | 1085 | chars[static_cast<int>(modulo(integer_part, radix))]; |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 1086 | integer_part /= radix; |
| 1087 | } while (integer_part >= 1.0); |
| 1088 | // Sanity check. |
| 1089 | ASSERT(integer_pos > 0); |
| 1090 | // Add sign if needed. |
| 1091 | if (is_negative) integer_buffer[integer_pos--] = '-'; |
| 1092 | |
| 1093 | // Convert the decimal part. Repeatedly multiply by the radix to |
| 1094 | // generate the next char. Never generate more than kBufferSize - 1 |
| 1095 | // chars. |
| 1096 | // |
| 1097 | // TODO(1093998): We will often generate a full decimal_buffer of |
| 1098 | // chars because hitting zero will often not happen. The right |
| 1099 | // solution would be to continue until the string representation can |
| 1100 | // be read back and yield the original value. To implement this |
| 1101 | // efficiently, we probably have to modify dtoa. |
| 1102 | int decimal_pos = 0; |
| 1103 | while ((decimal_part > 0.0) && (decimal_pos < kBufferSize - 1)) { |
| 1104 | decimal_part *= radix; |
| 1105 | decimal_buffer[decimal_pos++] = |
| 1106 | chars[static_cast<int>(floor(decimal_part))]; |
| 1107 | decimal_part -= floor(decimal_part); |
| 1108 | } |
| 1109 | decimal_buffer[decimal_pos] = '\0'; |
| 1110 | |
| 1111 | // Compute the result size. |
| 1112 | int integer_part_size = kBufferSize - 2 - integer_pos; |
| 1113 | // Make room for zero termination. |
| 1114 | unsigned result_size = integer_part_size + decimal_pos; |
| 1115 | // If the number has a decimal part, leave room for the period. |
| 1116 | if (decimal_pos > 0) result_size++; |
| 1117 | // Allocate result and fill in the parts. |
| 1118 | StringBuilder builder(result_size + 1); |
| 1119 | builder.AddSubstring(integer_buffer + integer_pos + 1, integer_part_size); |
| 1120 | if (decimal_pos > 0) builder.AddCharacter('.'); |
| 1121 | builder.AddSubstring(decimal_buffer, decimal_pos); |
| 1122 | return builder.Finalize(); |
| 1123 | } |
| 1124 | |
| 1125 | |
| 1126 | } } // namespace v8::internal |