Ben Murdoch | 3fb3ca8 | 2011-12-02 17:19:32 +0000 | [diff] [blame] | 1 | // Copyright 2011 the V8 project authors. All rights reserved. |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 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 | #ifndef V8_CONVERSIONS_INL_H_ |
| 29 | #define V8_CONVERSIONS_INL_H_ |
| 30 | |
Ben Murdoch | 3fb3ca8 | 2011-12-02 17:19:32 +0000 | [diff] [blame] | 31 | #include <limits.h> // Required for INT_MAX etc. |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 32 | #include <math.h> |
Ben Murdoch | 3fb3ca8 | 2011-12-02 17:19:32 +0000 | [diff] [blame] | 33 | #include <float.h> // Required for DBL_MAX and on Win32 for finite() |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 34 | #include <stdarg.h> |
Ben Murdoch | 589d697 | 2011-11-30 16:04:58 +0000 | [diff] [blame] | 35 | #include "globals.h" // Required for V8_INFINITY |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 36 | |
| 37 | // ---------------------------------------------------------------------------- |
| 38 | // Extra POSIX/ANSI functions for Win32/MSVC. |
| 39 | |
| 40 | #include "conversions.h" |
Ben Murdoch | 589d697 | 2011-11-30 16:04:58 +0000 | [diff] [blame] | 41 | #include "double.h" |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 42 | #include "platform.h" |
Ben Murdoch | 589d697 | 2011-11-30 16:04:58 +0000 | [diff] [blame] | 43 | #include "scanner.h" |
| 44 | #include "strtod.h" |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 45 | |
| 46 | namespace v8 { |
| 47 | namespace internal { |
| 48 | |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame] | 49 | inline double JunkStringValue() { |
| 50 | return BitCast<double, uint64_t>(kQuietNaNMask); |
Ben Murdoch | 3fb3ca8 | 2011-12-02 17:19:32 +0000 | [diff] [blame] | 51 | } |
| 52 | |
| 53 | |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 54 | // The fast double-to-unsigned-int conversion routine does not guarantee |
| 55 | // rounding towards zero, or any reasonable value if the argument is larger |
| 56 | // than what fits in an unsigned 32-bit integer. |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame] | 57 | inline unsigned int FastD2UI(double x) { |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 58 | // There is no unsigned version of lrint, so there is no fast path |
| 59 | // in this function as there is in FastD2I. Using lrint doesn't work |
| 60 | // for values of 2^31 and above. |
| 61 | |
| 62 | // Convert "small enough" doubles to uint32_t by fixing the 32 |
| 63 | // least significant non-fractional bits in the low 32 bits of the |
| 64 | // double, and reading them from there. |
| 65 | const double k2Pow52 = 4503599627370496.0; |
| 66 | bool negative = x < 0; |
| 67 | if (negative) { |
| 68 | x = -x; |
| 69 | } |
| 70 | if (x < k2Pow52) { |
| 71 | x += k2Pow52; |
| 72 | uint32_t result; |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 73 | Address mantissa_ptr = reinterpret_cast<Address>(&x); |
Steve Block | 6ded16b | 2010-05-10 14:33:55 +0100 | [diff] [blame] | 74 | // Copy least significant 32 bits of mantissa. |
| 75 | memcpy(&result, mantissa_ptr, sizeof(result)); |
| 76 | return negative ? ~result + 1 : result; |
| 77 | } |
| 78 | // Large number (outside uint32 range), Infinity or NaN. |
| 79 | return 0x80000000u; // Return integer indefinite. |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 80 | } |
| 81 | |
| 82 | |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame] | 83 | inline double DoubleToInteger(double x) { |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 84 | if (isnan(x)) return 0; |
| 85 | if (!isfinite(x) || x == 0) return x; |
| 86 | return (x >= 0) ? floor(x) : ceil(x); |
| 87 | } |
| 88 | |
| 89 | |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 90 | int32_t DoubleToInt32(double x) { |
| 91 | int32_t i = FastD2I(x); |
| 92 | if (FastI2D(i) == x) return i; |
Ben Murdoch | 589d697 | 2011-11-30 16:04:58 +0000 | [diff] [blame] | 93 | Double d(x); |
| 94 | int exponent = d.Exponent(); |
| 95 | if (exponent < 0) { |
| 96 | if (exponent <= -Double::kSignificandSize) return 0; |
| 97 | return d.Sign() * static_cast<int32_t>(d.Significand() >> -exponent); |
| 98 | } else { |
| 99 | if (exponent > 31) return 0; |
| 100 | return d.Sign() * static_cast<int32_t>(d.Significand() << exponent); |
| 101 | } |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 102 | } |
| 103 | |
| 104 | |
Ben Murdoch | 3fb3ca8 | 2011-12-02 17:19:32 +0000 | [diff] [blame] | 105 | template <class Iterator, class EndMark> |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame] | 106 | bool SubStringEquals(Iterator* current, |
| 107 | EndMark end, |
| 108 | const char* substring) { |
Ben Murdoch | 3fb3ca8 | 2011-12-02 17:19:32 +0000 | [diff] [blame] | 109 | ASSERT(**current == *substring); |
| 110 | for (substring++; *substring != '\0'; substring++) { |
| 111 | ++*current; |
| 112 | if (*current == end || **current != *substring) return false; |
| 113 | } |
| 114 | ++*current; |
| 115 | return true; |
| 116 | } |
| 117 | |
| 118 | |
| 119 | // Returns true if a nonspace character has been found and false if the |
| 120 | // end was been reached before finding a nonspace character. |
| 121 | template <class Iterator, class EndMark> |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame] | 122 | inline bool AdvanceToNonspace(UnicodeCache* unicode_cache, |
| 123 | Iterator* current, |
| 124 | EndMark end) { |
Ben Murdoch | 3fb3ca8 | 2011-12-02 17:19:32 +0000 | [diff] [blame] | 125 | while (*current != end) { |
| 126 | if (!unicode_cache->IsWhiteSpace(**current)) return true; |
| 127 | ++*current; |
| 128 | } |
| 129 | return false; |
| 130 | } |
| 131 | |
| 132 | |
| 133 | // Parsing integers with radix 2, 4, 8, 16, 32. Assumes current != end. |
| 134 | template <int radix_log_2, class Iterator, class EndMark> |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame] | 135 | double InternalStringToIntDouble(UnicodeCache* unicode_cache, |
| 136 | Iterator current, |
| 137 | EndMark end, |
| 138 | bool negative, |
| 139 | bool allow_trailing_junk) { |
Ben Murdoch | 3fb3ca8 | 2011-12-02 17:19:32 +0000 | [diff] [blame] | 140 | ASSERT(current != end); |
| 141 | |
| 142 | // Skip leading 0s. |
| 143 | while (*current == '0') { |
| 144 | ++current; |
| 145 | if (current == end) return SignedZero(negative); |
| 146 | } |
| 147 | |
| 148 | int64_t number = 0; |
| 149 | int exponent = 0; |
| 150 | const int radix = (1 << radix_log_2); |
| 151 | |
| 152 | do { |
| 153 | int digit; |
| 154 | if (*current >= '0' && *current <= '9' && *current < '0' + radix) { |
| 155 | digit = static_cast<char>(*current) - '0'; |
| 156 | } else if (radix > 10 && *current >= 'a' && *current < 'a' + radix - 10) { |
| 157 | digit = static_cast<char>(*current) - 'a' + 10; |
| 158 | } else if (radix > 10 && *current >= 'A' && *current < 'A' + radix - 10) { |
| 159 | digit = static_cast<char>(*current) - 'A' + 10; |
| 160 | } else { |
| 161 | if (allow_trailing_junk || |
| 162 | !AdvanceToNonspace(unicode_cache, ¤t, end)) { |
| 163 | break; |
| 164 | } else { |
| 165 | return JunkStringValue(); |
| 166 | } |
| 167 | } |
| 168 | |
| 169 | number = number * radix + digit; |
| 170 | int overflow = static_cast<int>(number >> 53); |
| 171 | if (overflow != 0) { |
| 172 | // Overflow occurred. Need to determine which direction to round the |
| 173 | // result. |
| 174 | int overflow_bits_count = 1; |
| 175 | while (overflow > 1) { |
| 176 | overflow_bits_count++; |
| 177 | overflow >>= 1; |
| 178 | } |
| 179 | |
| 180 | int dropped_bits_mask = ((1 << overflow_bits_count) - 1); |
| 181 | int dropped_bits = static_cast<int>(number) & dropped_bits_mask; |
| 182 | number >>= overflow_bits_count; |
| 183 | exponent = overflow_bits_count; |
| 184 | |
| 185 | bool zero_tail = true; |
| 186 | while (true) { |
| 187 | ++current; |
| 188 | if (current == end || !isDigit(*current, radix)) break; |
| 189 | zero_tail = zero_tail && *current == '0'; |
| 190 | exponent += radix_log_2; |
| 191 | } |
| 192 | |
| 193 | if (!allow_trailing_junk && |
| 194 | AdvanceToNonspace(unicode_cache, ¤t, end)) { |
| 195 | return JunkStringValue(); |
| 196 | } |
| 197 | |
| 198 | int middle_value = (1 << (overflow_bits_count - 1)); |
| 199 | if (dropped_bits > middle_value) { |
| 200 | number++; // Rounding up. |
| 201 | } else if (dropped_bits == middle_value) { |
| 202 | // Rounding to even to consistency with decimals: half-way case rounds |
| 203 | // up if significant part is odd and down otherwise. |
| 204 | if ((number & 1) != 0 || !zero_tail) { |
| 205 | number++; // Rounding up. |
| 206 | } |
| 207 | } |
| 208 | |
| 209 | // Rounding up may cause overflow. |
| 210 | if ((number & ((int64_t)1 << 53)) != 0) { |
| 211 | exponent++; |
| 212 | number >>= 1; |
| 213 | } |
| 214 | break; |
| 215 | } |
| 216 | ++current; |
| 217 | } while (current != end); |
| 218 | |
| 219 | ASSERT(number < ((int64_t)1 << 53)); |
| 220 | ASSERT(static_cast<int64_t>(static_cast<double>(number)) == number); |
| 221 | |
| 222 | if (exponent == 0) { |
| 223 | if (negative) { |
| 224 | if (number == 0) return -0.0; |
| 225 | number = -number; |
| 226 | } |
| 227 | return static_cast<double>(number); |
| 228 | } |
| 229 | |
| 230 | ASSERT(number != 0); |
| 231 | // The double could be constructed faster from number (mantissa), exponent |
| 232 | // and sign. Assuming it's a rare case more simple code is used. |
| 233 | return static_cast<double>(negative ? -number : number) * pow(2.0, exponent); |
| 234 | } |
| 235 | |
| 236 | |
| 237 | template <class Iterator, class EndMark> |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame] | 238 | double InternalStringToInt(UnicodeCache* unicode_cache, |
| 239 | Iterator current, |
| 240 | EndMark end, |
| 241 | int radix) { |
Ben Murdoch | 3fb3ca8 | 2011-12-02 17:19:32 +0000 | [diff] [blame] | 242 | const bool allow_trailing_junk = true; |
| 243 | const double empty_string_val = JunkStringValue(); |
| 244 | |
| 245 | if (!AdvanceToNonspace(unicode_cache, ¤t, end)) { |
| 246 | return empty_string_val; |
| 247 | } |
| 248 | |
| 249 | bool negative = false; |
| 250 | bool leading_zero = false; |
| 251 | |
| 252 | if (*current == '+') { |
| 253 | // Ignore leading sign; skip following spaces. |
| 254 | ++current; |
| 255 | if (current == end) { |
| 256 | return JunkStringValue(); |
| 257 | } |
| 258 | } else if (*current == '-') { |
| 259 | ++current; |
| 260 | if (current == end) { |
| 261 | return JunkStringValue(); |
| 262 | } |
| 263 | negative = true; |
| 264 | } |
| 265 | |
| 266 | if (radix == 0) { |
| 267 | // Radix detection. |
| 268 | if (*current == '0') { |
| 269 | ++current; |
| 270 | if (current == end) return SignedZero(negative); |
| 271 | if (*current == 'x' || *current == 'X') { |
| 272 | radix = 16; |
| 273 | ++current; |
| 274 | if (current == end) return JunkStringValue(); |
| 275 | } else { |
| 276 | radix = 8; |
| 277 | leading_zero = true; |
| 278 | } |
| 279 | } else { |
| 280 | radix = 10; |
| 281 | } |
| 282 | } else if (radix == 16) { |
| 283 | if (*current == '0') { |
| 284 | // Allow "0x" prefix. |
| 285 | ++current; |
| 286 | if (current == end) return SignedZero(negative); |
| 287 | if (*current == 'x' || *current == 'X') { |
| 288 | ++current; |
| 289 | if (current == end) return JunkStringValue(); |
| 290 | } else { |
| 291 | leading_zero = true; |
| 292 | } |
| 293 | } |
| 294 | } |
| 295 | |
| 296 | if (radix < 2 || radix > 36) return JunkStringValue(); |
| 297 | |
| 298 | // Skip leading zeros. |
| 299 | while (*current == '0') { |
| 300 | leading_zero = true; |
| 301 | ++current; |
| 302 | if (current == end) return SignedZero(negative); |
| 303 | } |
| 304 | |
| 305 | if (!leading_zero && !isDigit(*current, radix)) { |
| 306 | return JunkStringValue(); |
| 307 | } |
| 308 | |
| 309 | if (IsPowerOf2(radix)) { |
| 310 | switch (radix) { |
| 311 | case 2: |
| 312 | return InternalStringToIntDouble<1>( |
| 313 | unicode_cache, current, end, negative, allow_trailing_junk); |
| 314 | case 4: |
| 315 | return InternalStringToIntDouble<2>( |
| 316 | unicode_cache, current, end, negative, allow_trailing_junk); |
| 317 | case 8: |
| 318 | return InternalStringToIntDouble<3>( |
| 319 | unicode_cache, current, end, negative, allow_trailing_junk); |
| 320 | |
| 321 | case 16: |
| 322 | return InternalStringToIntDouble<4>( |
| 323 | unicode_cache, current, end, negative, allow_trailing_junk); |
| 324 | |
| 325 | case 32: |
| 326 | return InternalStringToIntDouble<5>( |
| 327 | unicode_cache, current, end, negative, allow_trailing_junk); |
| 328 | default: |
| 329 | UNREACHABLE(); |
| 330 | } |
| 331 | } |
| 332 | |
| 333 | if (radix == 10) { |
| 334 | // Parsing with strtod. |
| 335 | const int kMaxSignificantDigits = 309; // Doubles are less than 1.8e308. |
| 336 | // The buffer may contain up to kMaxSignificantDigits + 1 digits and a zero |
| 337 | // end. |
| 338 | const int kBufferSize = kMaxSignificantDigits + 2; |
| 339 | char buffer[kBufferSize]; |
| 340 | int buffer_pos = 0; |
| 341 | while (*current >= '0' && *current <= '9') { |
| 342 | if (buffer_pos <= kMaxSignificantDigits) { |
| 343 | // If the number has more than kMaxSignificantDigits it will be parsed |
| 344 | // as infinity. |
| 345 | ASSERT(buffer_pos < kBufferSize); |
| 346 | buffer[buffer_pos++] = static_cast<char>(*current); |
| 347 | } |
| 348 | ++current; |
| 349 | if (current == end) break; |
| 350 | } |
| 351 | |
| 352 | if (!allow_trailing_junk && |
| 353 | AdvanceToNonspace(unicode_cache, ¤t, end)) { |
| 354 | return JunkStringValue(); |
| 355 | } |
| 356 | |
| 357 | ASSERT(buffer_pos < kBufferSize); |
| 358 | buffer[buffer_pos] = '\0'; |
| 359 | Vector<const char> buffer_vector(buffer, buffer_pos); |
| 360 | return negative ? -Strtod(buffer_vector, 0) : Strtod(buffer_vector, 0); |
| 361 | } |
| 362 | |
| 363 | // The following code causes accumulating rounding error for numbers greater |
| 364 | // than ~2^56. It's explicitly allowed in the spec: "if R is not 2, 4, 8, 10, |
| 365 | // 16, or 32, then mathInt may be an implementation-dependent approximation to |
| 366 | // the mathematical integer value" (15.1.2.2). |
| 367 | |
| 368 | int lim_0 = '0' + (radix < 10 ? radix : 10); |
| 369 | int lim_a = 'a' + (radix - 10); |
| 370 | int lim_A = 'A' + (radix - 10); |
| 371 | |
| 372 | // NOTE: The code for computing the value may seem a bit complex at |
| 373 | // first glance. It is structured to use 32-bit multiply-and-add |
| 374 | // loops as long as possible to avoid loosing precision. |
| 375 | |
| 376 | double v = 0.0; |
| 377 | bool done = false; |
| 378 | do { |
| 379 | // Parse the longest part of the string starting at index j |
| 380 | // possible while keeping the multiplier, and thus the part |
| 381 | // itself, within 32 bits. |
| 382 | unsigned int part = 0, multiplier = 1; |
| 383 | while (true) { |
| 384 | int d; |
| 385 | if (*current >= '0' && *current < lim_0) { |
| 386 | d = *current - '0'; |
| 387 | } else if (*current >= 'a' && *current < lim_a) { |
| 388 | d = *current - 'a' + 10; |
| 389 | } else if (*current >= 'A' && *current < lim_A) { |
| 390 | d = *current - 'A' + 10; |
| 391 | } else { |
| 392 | done = true; |
| 393 | break; |
| 394 | } |
| 395 | |
| 396 | // Update the value of the part as long as the multiplier fits |
| 397 | // in 32 bits. When we can't guarantee that the next iteration |
| 398 | // will not overflow the multiplier, we stop parsing the part |
| 399 | // by leaving the loop. |
| 400 | const unsigned int kMaximumMultiplier = 0xffffffffU / 36; |
| 401 | uint32_t m = multiplier * radix; |
| 402 | if (m > kMaximumMultiplier) break; |
| 403 | part = part * radix + d; |
| 404 | multiplier = m; |
| 405 | ASSERT(multiplier > part); |
| 406 | |
| 407 | ++current; |
| 408 | if (current == end) { |
| 409 | done = true; |
| 410 | break; |
| 411 | } |
| 412 | } |
| 413 | |
| 414 | // Update the value and skip the part in the string. |
| 415 | v = v * multiplier + part; |
| 416 | } while (!done); |
| 417 | |
| 418 | if (!allow_trailing_junk && |
| 419 | AdvanceToNonspace(unicode_cache, ¤t, end)) { |
| 420 | return JunkStringValue(); |
| 421 | } |
| 422 | |
| 423 | return negative ? -v : v; |
| 424 | } |
| 425 | |
| 426 | |
| 427 | // Converts a string to a double value. Assumes the Iterator supports |
| 428 | // the following operations: |
| 429 | // 1. current == end (other ops are not allowed), current != end. |
| 430 | // 2. *current - gets the current character in the sequence. |
| 431 | // 3. ++current (advances the position). |
| 432 | template <class Iterator, class EndMark> |
Ben Murdoch | 3ef787d | 2012-04-12 10:51:47 +0100 | [diff] [blame] | 433 | double InternalStringToDouble(UnicodeCache* unicode_cache, |
| 434 | Iterator current, |
| 435 | EndMark end, |
| 436 | int flags, |
| 437 | double empty_string_val) { |
Ben Murdoch | 3fb3ca8 | 2011-12-02 17:19:32 +0000 | [diff] [blame] | 438 | // To make sure that iterator dereferencing is valid the following |
| 439 | // convention is used: |
| 440 | // 1. Each '++current' statement is followed by check for equality to 'end'. |
| 441 | // 2. If AdvanceToNonspace returned false then current == end. |
| 442 | // 3. If 'current' becomes be equal to 'end' the function returns or goes to |
| 443 | // 'parsing_done'. |
| 444 | // 4. 'current' is not dereferenced after the 'parsing_done' label. |
| 445 | // 5. Code before 'parsing_done' may rely on 'current != end'. |
| 446 | if (!AdvanceToNonspace(unicode_cache, ¤t, end)) { |
| 447 | return empty_string_val; |
| 448 | } |
| 449 | |
| 450 | const bool allow_trailing_junk = (flags & ALLOW_TRAILING_JUNK) != 0; |
| 451 | |
| 452 | // The longest form of simplified number is: "-<significant digits>'.1eXXX\0". |
| 453 | const int kBufferSize = kMaxSignificantDigits + 10; |
| 454 | char buffer[kBufferSize]; // NOLINT: size is known at compile time. |
| 455 | int buffer_pos = 0; |
| 456 | |
| 457 | // Exponent will be adjusted if insignificant digits of the integer part |
| 458 | // or insignificant leading zeros of the fractional part are dropped. |
| 459 | int exponent = 0; |
| 460 | int significant_digits = 0; |
| 461 | int insignificant_digits = 0; |
| 462 | bool nonzero_digit_dropped = false; |
| 463 | |
| 464 | bool negative = false; |
| 465 | |
| 466 | if (*current == '+') { |
| 467 | // Ignore leading sign. |
| 468 | ++current; |
| 469 | if (current == end) return JunkStringValue(); |
| 470 | } else if (*current == '-') { |
| 471 | ++current; |
| 472 | if (current == end) return JunkStringValue(); |
| 473 | negative = true; |
| 474 | } |
| 475 | |
| 476 | static const char kInfinitySymbol[] = "Infinity"; |
| 477 | if (*current == kInfinitySymbol[0]) { |
| 478 | if (!SubStringEquals(¤t, end, kInfinitySymbol)) { |
| 479 | return JunkStringValue(); |
| 480 | } |
| 481 | |
| 482 | if (!allow_trailing_junk && |
| 483 | AdvanceToNonspace(unicode_cache, ¤t, end)) { |
| 484 | return JunkStringValue(); |
| 485 | } |
| 486 | |
| 487 | ASSERT(buffer_pos == 0); |
| 488 | return negative ? -V8_INFINITY : V8_INFINITY; |
| 489 | } |
| 490 | |
| 491 | bool leading_zero = false; |
| 492 | if (*current == '0') { |
| 493 | ++current; |
| 494 | if (current == end) return SignedZero(negative); |
| 495 | |
| 496 | leading_zero = true; |
| 497 | |
| 498 | // It could be hexadecimal value. |
| 499 | if ((flags & ALLOW_HEX) && (*current == 'x' || *current == 'X')) { |
| 500 | ++current; |
| 501 | if (current == end || !isDigit(*current, 16)) { |
| 502 | return JunkStringValue(); // "0x". |
| 503 | } |
| 504 | |
| 505 | return InternalStringToIntDouble<4>(unicode_cache, |
| 506 | current, |
| 507 | end, |
| 508 | negative, |
| 509 | allow_trailing_junk); |
| 510 | } |
| 511 | |
| 512 | // Ignore leading zeros in the integer part. |
| 513 | while (*current == '0') { |
| 514 | ++current; |
| 515 | if (current == end) return SignedZero(negative); |
| 516 | } |
| 517 | } |
| 518 | |
| 519 | bool octal = leading_zero && (flags & ALLOW_OCTALS) != 0; |
| 520 | |
| 521 | // Copy significant digits of the integer part (if any) to the buffer. |
| 522 | while (*current >= '0' && *current <= '9') { |
| 523 | if (significant_digits < kMaxSignificantDigits) { |
| 524 | ASSERT(buffer_pos < kBufferSize); |
| 525 | buffer[buffer_pos++] = static_cast<char>(*current); |
| 526 | significant_digits++; |
| 527 | // Will later check if it's an octal in the buffer. |
| 528 | } else { |
| 529 | insignificant_digits++; // Move the digit into the exponential part. |
| 530 | nonzero_digit_dropped = nonzero_digit_dropped || *current != '0'; |
| 531 | } |
| 532 | octal = octal && *current < '8'; |
| 533 | ++current; |
| 534 | if (current == end) goto parsing_done; |
| 535 | } |
| 536 | |
| 537 | if (significant_digits == 0) { |
| 538 | octal = false; |
| 539 | } |
| 540 | |
| 541 | if (*current == '.') { |
| 542 | if (octal && !allow_trailing_junk) return JunkStringValue(); |
| 543 | if (octal) goto parsing_done; |
| 544 | |
| 545 | ++current; |
| 546 | if (current == end) { |
| 547 | if (significant_digits == 0 && !leading_zero) { |
| 548 | return JunkStringValue(); |
| 549 | } else { |
| 550 | goto parsing_done; |
| 551 | } |
| 552 | } |
| 553 | |
| 554 | if (significant_digits == 0) { |
| 555 | // octal = false; |
| 556 | // Integer part consists of 0 or is absent. Significant digits start after |
| 557 | // leading zeros (if any). |
| 558 | while (*current == '0') { |
| 559 | ++current; |
| 560 | if (current == end) return SignedZero(negative); |
| 561 | exponent--; // Move this 0 into the exponent. |
| 562 | } |
| 563 | } |
| 564 | |
| 565 | // There is a fractional part. We don't emit a '.', but adjust the exponent |
| 566 | // instead. |
| 567 | while (*current >= '0' && *current <= '9') { |
| 568 | if (significant_digits < kMaxSignificantDigits) { |
| 569 | ASSERT(buffer_pos < kBufferSize); |
| 570 | buffer[buffer_pos++] = static_cast<char>(*current); |
| 571 | significant_digits++; |
| 572 | exponent--; |
| 573 | } else { |
| 574 | // Ignore insignificant digits in the fractional part. |
| 575 | nonzero_digit_dropped = nonzero_digit_dropped || *current != '0'; |
| 576 | } |
| 577 | ++current; |
| 578 | if (current == end) goto parsing_done; |
| 579 | } |
| 580 | } |
| 581 | |
| 582 | if (!leading_zero && exponent == 0 && significant_digits == 0) { |
| 583 | // If leading_zeros is true then the string contains zeros. |
| 584 | // If exponent < 0 then string was [+-]\.0*... |
| 585 | // If significant_digits != 0 the string is not equal to 0. |
| 586 | // Otherwise there are no digits in the string. |
| 587 | return JunkStringValue(); |
| 588 | } |
| 589 | |
| 590 | // Parse exponential part. |
| 591 | if (*current == 'e' || *current == 'E') { |
| 592 | if (octal) return JunkStringValue(); |
| 593 | ++current; |
| 594 | if (current == end) { |
| 595 | if (allow_trailing_junk) { |
| 596 | goto parsing_done; |
| 597 | } else { |
| 598 | return JunkStringValue(); |
| 599 | } |
| 600 | } |
| 601 | char sign = '+'; |
| 602 | if (*current == '+' || *current == '-') { |
| 603 | sign = static_cast<char>(*current); |
| 604 | ++current; |
| 605 | if (current == end) { |
| 606 | if (allow_trailing_junk) { |
| 607 | goto parsing_done; |
| 608 | } else { |
| 609 | return JunkStringValue(); |
| 610 | } |
| 611 | } |
| 612 | } |
| 613 | |
| 614 | if (current == end || *current < '0' || *current > '9') { |
| 615 | if (allow_trailing_junk) { |
| 616 | goto parsing_done; |
| 617 | } else { |
| 618 | return JunkStringValue(); |
| 619 | } |
| 620 | } |
| 621 | |
| 622 | const int max_exponent = INT_MAX / 2; |
| 623 | ASSERT(-max_exponent / 2 <= exponent && exponent <= max_exponent / 2); |
| 624 | int num = 0; |
| 625 | do { |
| 626 | // Check overflow. |
| 627 | int digit = *current - '0'; |
| 628 | if (num >= max_exponent / 10 |
| 629 | && !(num == max_exponent / 10 && digit <= max_exponent % 10)) { |
| 630 | num = max_exponent; |
| 631 | } else { |
| 632 | num = num * 10 + digit; |
| 633 | } |
| 634 | ++current; |
| 635 | } while (current != end && *current >= '0' && *current <= '9'); |
| 636 | |
| 637 | exponent += (sign == '-' ? -num : num); |
| 638 | } |
| 639 | |
| 640 | if (!allow_trailing_junk && |
| 641 | AdvanceToNonspace(unicode_cache, ¤t, end)) { |
| 642 | return JunkStringValue(); |
| 643 | } |
| 644 | |
| 645 | parsing_done: |
| 646 | exponent += insignificant_digits; |
| 647 | |
| 648 | if (octal) { |
| 649 | return InternalStringToIntDouble<3>(unicode_cache, |
| 650 | buffer, |
| 651 | buffer + buffer_pos, |
| 652 | negative, |
| 653 | allow_trailing_junk); |
| 654 | } |
| 655 | |
| 656 | if (nonzero_digit_dropped) { |
| 657 | buffer[buffer_pos++] = '1'; |
| 658 | exponent--; |
| 659 | } |
| 660 | |
| 661 | ASSERT(buffer_pos < kBufferSize); |
| 662 | buffer[buffer_pos] = '\0'; |
| 663 | |
| 664 | double converted = Strtod(Vector<const char>(buffer, buffer_pos), exponent); |
| 665 | return negative ? -converted : converted; |
| 666 | } |
| 667 | |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 668 | } } // namespace v8::internal |
| 669 | |
| 670 | #endif // V8_CONVERSIONS_INL_H_ |