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> |
| 29 | |
| 30 | #include "v8.h" |
| 31 | |
| 32 | #include "conversions-inl.h" |
| 33 | #include "factory.h" |
| 34 | #include "scanner.h" |
| 35 | |
| 36 | namespace v8 { |
| 37 | namespace internal { |
| 38 | |
| 39 | int HexValue(uc32 c) { |
| 40 | if ('0' <= c && c <= '9') |
| 41 | return c - '0'; |
| 42 | if ('a' <= c && c <= 'f') |
| 43 | return c - 'a' + 10; |
| 44 | if ('A' <= c && c <= 'F') |
| 45 | return c - 'A' + 10; |
| 46 | return -1; |
| 47 | } |
| 48 | |
| 49 | |
| 50 | // Provide a common interface to getting a character at a certain |
| 51 | // index from a char* or a String object. |
| 52 | static inline int GetChar(const char* str, int index) { |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 53 | ASSERT(index >= 0 && index < StrLength(str)); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 54 | return str[index]; |
| 55 | } |
| 56 | |
| 57 | |
| 58 | static inline int GetChar(String* str, int index) { |
| 59 | return str->Get(index); |
| 60 | } |
| 61 | |
| 62 | |
| 63 | static inline int GetLength(const char* str) { |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 64 | return StrLength(str); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 65 | } |
| 66 | |
| 67 | |
| 68 | static inline int GetLength(String* str) { |
| 69 | return str->length(); |
| 70 | } |
| 71 | |
| 72 | |
| 73 | static inline const char* GetCString(const char* str, int index) { |
| 74 | return str + index; |
| 75 | } |
| 76 | |
| 77 | |
| 78 | static inline const char* GetCString(String* str, int index) { |
| 79 | int length = str->length(); |
| 80 | char* result = NewArray<char>(length + 1); |
| 81 | for (int i = index; i < length; i++) { |
| 82 | uc16 c = str->Get(i); |
| 83 | if (c <= 127) { |
| 84 | result[i - index] = static_cast<char>(c); |
| 85 | } else { |
| 86 | result[i - index] = 127; // Force number parsing to fail. |
| 87 | } |
| 88 | } |
| 89 | result[length - index] = '\0'; |
| 90 | return result; |
| 91 | } |
| 92 | |
| 93 | |
| 94 | static inline void ReleaseCString(const char* original, const char* str) { |
| 95 | } |
| 96 | |
| 97 | |
| 98 | static inline void ReleaseCString(String* original, const char* str) { |
| 99 | DeleteArray(const_cast<char *>(str)); |
| 100 | } |
| 101 | |
| 102 | |
| 103 | static inline bool IsSpace(const char* str, int index) { |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 104 | ASSERT(index >= 0 && index < StrLength(str)); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 105 | return Scanner::kIsWhiteSpace.get(str[index]); |
| 106 | } |
| 107 | |
| 108 | |
| 109 | static inline bool IsSpace(String* str, int index) { |
| 110 | return Scanner::kIsWhiteSpace.get(str->Get(index)); |
| 111 | } |
| 112 | |
| 113 | |
| 114 | static inline bool SubStringEquals(const char* str, |
| 115 | int index, |
| 116 | const char* other) { |
| 117 | return strncmp(str + index, other, strlen(other)) != 0; |
| 118 | } |
| 119 | |
| 120 | |
| 121 | static inline bool SubStringEquals(String* str, int index, const char* other) { |
| 122 | HandleScope scope; |
| 123 | int str_length = str->length(); |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 124 | int other_length = StrLength(other); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 125 | int end = index + other_length < str_length ? |
| 126 | index + other_length : |
| 127 | str_length; |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 128 | Handle<String> substring = |
| 129 | Factory::NewSubString(Handle<String>(str), index, end); |
| 130 | return substring->IsEqualTo(Vector<const char>(other, other_length)); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 131 | } |
| 132 | |
| 133 | |
| 134 | // Check if a string should be parsed as an octal number. The string |
| 135 | // can be either a char* or a String*. |
| 136 | template<class S> |
| 137 | static bool ShouldParseOctal(S* s, int i) { |
| 138 | int index = i; |
| 139 | int len = GetLength(s); |
| 140 | if (index < len && GetChar(s, index) != '0') return false; |
| 141 | |
| 142 | // If the first real character (following '0') is not an octal |
| 143 | // digit, bail out early. This also takes care of numbers of the |
| 144 | // forms 0.xxx and 0exxx by not allowing the first 0 to be |
| 145 | // interpreted as an octal. |
| 146 | index++; |
| 147 | if (index < len) { |
| 148 | int d = GetChar(s, index) - '0'; |
| 149 | if (d < 0 || d > 7) return false; |
| 150 | } else { |
| 151 | return false; |
| 152 | } |
| 153 | |
| 154 | // Traverse all digits (including the first). If there is an octal |
| 155 | // prefix which is not a part of a longer decimal prefix, we return |
| 156 | // true. Otherwise, false is returned. |
| 157 | while (index < len) { |
| 158 | int d = GetChar(s, index++) - '0'; |
| 159 | if (d == 8 || d == 9) return false; |
| 160 | if (d < 0 || d > 7) return true; |
| 161 | } |
| 162 | return true; |
| 163 | } |
| 164 | |
| 165 | |
| 166 | extern "C" double gay_strtod(const char* s00, const char** se); |
| 167 | |
| 168 | |
| 169 | // Parse an int from a string starting a given index and in a given |
| 170 | // radix. The string can be either a char* or a String*. |
| 171 | template <class S> |
| 172 | static int InternalStringToInt(S* s, int i, int radix, double* value) { |
| 173 | int len = GetLength(s); |
| 174 | |
| 175 | // Setup limits for computing the value. |
| 176 | ASSERT(2 <= radix && radix <= 36); |
| 177 | int lim_0 = '0' + (radix < 10 ? radix : 10); |
| 178 | int lim_a = 'a' + (radix - 10); |
| 179 | int lim_A = 'A' + (radix - 10); |
| 180 | |
| 181 | // NOTE: The code for computing the value may seem a bit complex at |
| 182 | // first glance. It is structured to use 32-bit multiply-and-add |
| 183 | // loops as long as possible to avoid loosing precision. |
| 184 | |
| 185 | double v = 0.0; |
| 186 | int j; |
| 187 | for (j = i; j < len;) { |
| 188 | // Parse the longest part of the string starting at index j |
| 189 | // possible while keeping the multiplier, and thus the part |
| 190 | // itself, within 32 bits. |
| 191 | uint32_t part = 0, multiplier = 1; |
| 192 | int k; |
| 193 | for (k = j; k < len; k++) { |
| 194 | int c = GetChar(s, k); |
| 195 | if (c >= '0' && c < lim_0) { |
| 196 | c = c - '0'; |
| 197 | } else if (c >= 'a' && c < lim_a) { |
| 198 | c = c - 'a' + 10; |
| 199 | } else if (c >= 'A' && c < lim_A) { |
| 200 | c = c - 'A' + 10; |
| 201 | } else { |
| 202 | break; |
| 203 | } |
| 204 | |
| 205 | // Update the value of the part as long as the multiplier fits |
| 206 | // in 32 bits. When we can't guarantee that the next iteration |
| 207 | // will not overflow the multiplier, we stop parsing the part |
| 208 | // by leaving the loop. |
| 209 | static const uint32_t kMaximumMultiplier = 0xffffffffU / 36; |
| 210 | uint32_t m = multiplier * radix; |
| 211 | if (m > kMaximumMultiplier) break; |
| 212 | part = part * radix + c; |
| 213 | multiplier = m; |
| 214 | ASSERT(multiplier > part); |
| 215 | } |
| 216 | |
| 217 | // Compute the number of part digits. If no digits were parsed; |
| 218 | // we're done parsing the entire string. |
| 219 | int digits = k - j; |
| 220 | if (digits == 0) break; |
| 221 | |
| 222 | // Update the value and skip the part in the string. |
| 223 | ASSERT(multiplier == |
| 224 | pow(static_cast<double>(radix), static_cast<double>(digits))); |
| 225 | v = v * multiplier + part; |
| 226 | j = k; |
| 227 | } |
| 228 | |
| 229 | // If the resulting value is larger than 2^53 the value does not fit |
| 230 | // in the mantissa of the double and there is a loss of precision. |
| 231 | // When the value is larger than 2^53 the rounding depends on the |
| 232 | // code generation. If the code generator spills the double value |
| 233 | // it uses 64 bits and if it does not it uses 80 bits. |
| 234 | // |
| 235 | // If there is a potential for overflow we resort to strtod for |
| 236 | // radix 10 numbers to get higher precision. For numbers in another |
| 237 | // radix we live with the loss of precision. |
| 238 | static const double kPreciseConversionLimit = 9007199254740992.0; |
| 239 | if (radix == 10 && v > kPreciseConversionLimit) { |
| 240 | const char* cstr = GetCString(s, i); |
| 241 | const char* end; |
| 242 | v = gay_strtod(cstr, &end); |
| 243 | ReleaseCString(s, cstr); |
| 244 | } |
| 245 | |
| 246 | *value = v; |
| 247 | return j; |
| 248 | } |
| 249 | |
| 250 | |
| 251 | int StringToInt(String* str, int index, int radix, double* value) { |
| 252 | return InternalStringToInt(str, index, radix, value); |
| 253 | } |
| 254 | |
| 255 | |
| 256 | int StringToInt(const char* str, int index, int radix, double* value) { |
| 257 | return InternalStringToInt(const_cast<char*>(str), index, radix, value); |
| 258 | } |
| 259 | |
| 260 | |
| 261 | static const double JUNK_STRING_VALUE = OS::nan_value(); |
| 262 | |
| 263 | |
| 264 | // Convert a string to a double value. The string can be either a |
| 265 | // char* or a String*. |
| 266 | template<class S> |
| 267 | static double InternalStringToDouble(S* str, |
| 268 | int flags, |
| 269 | double empty_string_val) { |
| 270 | double result = 0.0; |
| 271 | int index = 0; |
| 272 | |
| 273 | int len = GetLength(str); |
| 274 | |
| 275 | // Skip leading spaces. |
| 276 | while ((index < len) && IsSpace(str, index)) index++; |
| 277 | |
| 278 | // Is the string empty? |
| 279 | if (index >= len) return empty_string_val; |
| 280 | |
| 281 | // Get the first character. |
| 282 | uint16_t first = GetChar(str, index); |
| 283 | |
| 284 | // Numbers can only start with '-', '+', '.', 'I' (Infinity), or a digit. |
| 285 | if (first != '-' && first != '+' && first != '.' && first != 'I' && |
| 286 | (first > '9' || first < '0')) { |
| 287 | return JUNK_STRING_VALUE; |
| 288 | } |
| 289 | |
| 290 | // Compute sign of result based on first character. |
| 291 | int sign = 1; |
| 292 | if (first == '-') { |
| 293 | sign = -1; |
| 294 | index++; |
| 295 | // String only containing a '-' are junk chars. |
| 296 | if (index == len) return JUNK_STRING_VALUE; |
| 297 | } |
| 298 | |
| 299 | // do we have a hex number? |
| 300 | // (since the string is 0-terminated, it's ok to look one char beyond the end) |
| 301 | if ((flags & ALLOW_HEX) != 0 && |
| 302 | (index + 1) < len && |
| 303 | GetChar(str, index) == '0' && |
| 304 | (GetChar(str, index + 1) == 'x' || GetChar(str, index + 1) == 'X')) { |
| 305 | index += 2; |
| 306 | index = StringToInt(str, index, 16, &result); |
| 307 | } else if ((flags & ALLOW_OCTALS) != 0 && ShouldParseOctal(str, index)) { |
| 308 | // NOTE: We optimistically try to parse the number as an octal (if |
| 309 | // we're allowed to), even though this is not as dictated by |
| 310 | // ECMA-262. The reason for doing this is compatibility with IE and |
| 311 | // Firefox. |
| 312 | index = StringToInt(str, index, 8, &result); |
| 313 | } else { |
| 314 | const char* cstr = GetCString(str, index); |
| 315 | const char* end; |
| 316 | // Optimistically parse the number and then, if that fails, |
| 317 | // check if it might have been {+,-,}Infinity. |
| 318 | result = gay_strtod(cstr, &end); |
| 319 | ReleaseCString(str, cstr); |
| 320 | if (result != 0.0 || end != cstr) { |
| 321 | // It appears that strtod worked |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 322 | index += static_cast<int>(end - cstr); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 323 | } else { |
| 324 | // Check for {+,-,}Infinity |
| 325 | bool is_negative = (GetChar(str, index) == '-'); |
| 326 | if (GetChar(str, index) == '+' || GetChar(str, index) == '-') |
| 327 | index++; |
| 328 | if (!SubStringEquals(str, index, "Infinity")) |
| 329 | return JUNK_STRING_VALUE; |
| 330 | result = is_negative ? -V8_INFINITY : V8_INFINITY; |
| 331 | index += 8; |
| 332 | } |
| 333 | } |
| 334 | |
| 335 | if ((flags & ALLOW_TRAILING_JUNK) == 0) { |
| 336 | // skip trailing spaces |
| 337 | while ((index < len) && IsSpace(str, index)) index++; |
| 338 | // string ending with junk? |
| 339 | if (index < len) return JUNK_STRING_VALUE; |
| 340 | } |
| 341 | |
| 342 | return sign * result; |
| 343 | } |
| 344 | |
| 345 | |
| 346 | double StringToDouble(String* str, int flags, double empty_string_val) { |
| 347 | return InternalStringToDouble(str, flags, empty_string_val); |
| 348 | } |
| 349 | |
| 350 | |
| 351 | double StringToDouble(const char* str, int flags, double empty_string_val) { |
| 352 | return InternalStringToDouble(str, flags, empty_string_val); |
| 353 | } |
| 354 | |
| 355 | |
| 356 | extern "C" char* dtoa(double d, int mode, int ndigits, |
| 357 | int* decpt, int* sign, char** rve); |
| 358 | |
| 359 | extern "C" void freedtoa(char* s); |
| 360 | |
| 361 | const char* DoubleToCString(double v, Vector<char> buffer) { |
| 362 | StringBuilder builder(buffer.start(), buffer.length()); |
| 363 | |
| 364 | switch (fpclassify(v)) { |
| 365 | case FP_NAN: |
| 366 | builder.AddString("NaN"); |
| 367 | break; |
| 368 | |
| 369 | case FP_INFINITE: |
| 370 | if (v < 0.0) { |
| 371 | builder.AddString("-Infinity"); |
| 372 | } else { |
| 373 | builder.AddString("Infinity"); |
| 374 | } |
| 375 | break; |
| 376 | |
| 377 | case FP_ZERO: |
| 378 | builder.AddCharacter('0'); |
| 379 | break; |
| 380 | |
| 381 | default: { |
| 382 | int decimal_point; |
| 383 | int sign; |
| 384 | |
| 385 | char* decimal_rep = dtoa(v, 0, 0, &decimal_point, &sign, NULL); |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 386 | int length = StrLength(decimal_rep); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 387 | |
| 388 | if (sign) builder.AddCharacter('-'); |
| 389 | |
| 390 | if (length <= decimal_point && decimal_point <= 21) { |
| 391 | // ECMA-262 section 9.8.1 step 6. |
| 392 | builder.AddString(decimal_rep); |
| 393 | builder.AddPadding('0', decimal_point - length); |
| 394 | |
| 395 | } else if (0 < decimal_point && decimal_point <= 21) { |
| 396 | // ECMA-262 section 9.8.1 step 7. |
| 397 | builder.AddSubstring(decimal_rep, decimal_point); |
| 398 | builder.AddCharacter('.'); |
| 399 | builder.AddString(decimal_rep + decimal_point); |
| 400 | |
| 401 | } else if (decimal_point <= 0 && decimal_point > -6) { |
| 402 | // ECMA-262 section 9.8.1 step 8. |
| 403 | builder.AddString("0."); |
| 404 | builder.AddPadding('0', -decimal_point); |
| 405 | builder.AddString(decimal_rep); |
| 406 | |
| 407 | } else { |
| 408 | // ECMA-262 section 9.8.1 step 9 and 10 combined. |
| 409 | builder.AddCharacter(decimal_rep[0]); |
| 410 | if (length != 1) { |
| 411 | builder.AddCharacter('.'); |
| 412 | builder.AddString(decimal_rep + 1); |
| 413 | } |
| 414 | builder.AddCharacter('e'); |
| 415 | builder.AddCharacter((decimal_point >= 0) ? '+' : '-'); |
| 416 | int exponent = decimal_point - 1; |
| 417 | if (exponent < 0) exponent = -exponent; |
| 418 | builder.AddFormatted("%d", exponent); |
| 419 | } |
| 420 | |
| 421 | freedtoa(decimal_rep); |
| 422 | } |
| 423 | } |
| 424 | return builder.Finalize(); |
| 425 | } |
| 426 | |
| 427 | |
| 428 | const char* IntToCString(int n, Vector<char> buffer) { |
| 429 | bool negative = false; |
| 430 | if (n < 0) { |
| 431 | // We must not negate the most negative int. |
| 432 | if (n == kMinInt) return DoubleToCString(n, buffer); |
| 433 | negative = true; |
| 434 | n = -n; |
| 435 | } |
| 436 | // Build the string backwards from the least significant digit. |
| 437 | int i = buffer.length(); |
| 438 | buffer[--i] = '\0'; |
| 439 | do { |
| 440 | buffer[--i] = '0' + (n % 10); |
| 441 | n /= 10; |
| 442 | } while (n); |
| 443 | if (negative) buffer[--i] = '-'; |
| 444 | return buffer.start() + i; |
| 445 | } |
| 446 | |
| 447 | |
| 448 | char* DoubleToFixedCString(double value, int f) { |
| 449 | ASSERT(f >= 0); |
| 450 | |
| 451 | bool negative = false; |
| 452 | double abs_value = value; |
| 453 | if (value < 0) { |
| 454 | abs_value = -value; |
| 455 | negative = true; |
| 456 | } |
| 457 | |
| 458 | if (abs_value >= 1e21) { |
| 459 | char arr[100]; |
| 460 | Vector<char> buffer(arr, ARRAY_SIZE(arr)); |
| 461 | return StrDup(DoubleToCString(value, buffer)); |
| 462 | } |
| 463 | |
| 464 | // Find a sufficiently precise decimal representation of n. |
| 465 | int decimal_point; |
| 466 | int sign; |
| 467 | char* decimal_rep = dtoa(abs_value, 3, f, &decimal_point, &sign, NULL); |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 468 | int decimal_rep_length = StrLength(decimal_rep); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 469 | |
| 470 | // Create a representation that is padded with zeros if needed. |
| 471 | int zero_prefix_length = 0; |
| 472 | int zero_postfix_length = 0; |
| 473 | |
| 474 | if (decimal_point <= 0) { |
| 475 | zero_prefix_length = -decimal_point + 1; |
| 476 | decimal_point = 1; |
| 477 | } |
| 478 | |
| 479 | if (zero_prefix_length + decimal_rep_length < decimal_point + f) { |
| 480 | zero_postfix_length = decimal_point + f - decimal_rep_length - |
| 481 | zero_prefix_length; |
| 482 | } |
| 483 | |
| 484 | unsigned rep_length = |
| 485 | zero_prefix_length + decimal_rep_length + zero_postfix_length; |
| 486 | StringBuilder rep_builder(rep_length + 1); |
| 487 | rep_builder.AddPadding('0', zero_prefix_length); |
| 488 | rep_builder.AddString(decimal_rep); |
| 489 | rep_builder.AddPadding('0', zero_postfix_length); |
| 490 | char* rep = rep_builder.Finalize(); |
| 491 | freedtoa(decimal_rep); |
| 492 | |
| 493 | // Create the result string by appending a minus and putting in a |
| 494 | // decimal point if needed. |
| 495 | unsigned result_size = decimal_point + f + 2; |
| 496 | StringBuilder builder(result_size + 1); |
| 497 | if (negative) builder.AddCharacter('-'); |
| 498 | builder.AddSubstring(rep, decimal_point); |
| 499 | if (f > 0) { |
| 500 | builder.AddCharacter('.'); |
| 501 | builder.AddSubstring(rep + decimal_point, f); |
| 502 | } |
| 503 | DeleteArray(rep); |
| 504 | return builder.Finalize(); |
| 505 | } |
| 506 | |
| 507 | |
| 508 | static char* CreateExponentialRepresentation(char* decimal_rep, |
| 509 | int exponent, |
| 510 | bool negative, |
| 511 | int significant_digits) { |
| 512 | bool negative_exponent = false; |
| 513 | if (exponent < 0) { |
| 514 | negative_exponent = true; |
| 515 | exponent = -exponent; |
| 516 | } |
| 517 | |
| 518 | // Leave room in the result for appending a minus, for a period, the |
| 519 | // letter 'e', a minus or a plus depending on the exponent, and a |
| 520 | // three digit exponent. |
| 521 | unsigned result_size = significant_digits + 7; |
| 522 | StringBuilder builder(result_size + 1); |
| 523 | |
| 524 | if (negative) builder.AddCharacter('-'); |
| 525 | builder.AddCharacter(decimal_rep[0]); |
| 526 | if (significant_digits != 1) { |
| 527 | builder.AddCharacter('.'); |
| 528 | builder.AddString(decimal_rep + 1); |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 529 | int rep_length = StrLength(decimal_rep); |
| 530 | builder.AddPadding('0', significant_digits - rep_length); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 531 | } |
| 532 | |
| 533 | builder.AddCharacter('e'); |
| 534 | builder.AddCharacter(negative_exponent ? '-' : '+'); |
| 535 | builder.AddFormatted("%d", exponent); |
| 536 | return builder.Finalize(); |
| 537 | } |
| 538 | |
| 539 | |
| 540 | |
| 541 | char* DoubleToExponentialCString(double value, int f) { |
| 542 | // f might be -1 to signal that f was undefined in JavaScript. |
| 543 | ASSERT(f >= -1 && f <= 20); |
| 544 | |
| 545 | bool negative = false; |
| 546 | if (value < 0) { |
| 547 | value = -value; |
| 548 | negative = true; |
| 549 | } |
| 550 | |
| 551 | // Find a sufficiently precise decimal representation of n. |
| 552 | int decimal_point; |
| 553 | int sign; |
| 554 | char* decimal_rep = NULL; |
| 555 | if (f == -1) { |
| 556 | decimal_rep = dtoa(value, 0, 0, &decimal_point, &sign, NULL); |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 557 | f = StrLength(decimal_rep) - 1; |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 558 | } else { |
| 559 | decimal_rep = dtoa(value, 2, f + 1, &decimal_point, &sign, NULL); |
| 560 | } |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 561 | int decimal_rep_length = StrLength(decimal_rep); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 562 | ASSERT(decimal_rep_length > 0); |
| 563 | ASSERT(decimal_rep_length <= f + 1); |
| 564 | USE(decimal_rep_length); |
| 565 | |
| 566 | int exponent = decimal_point - 1; |
| 567 | char* result = |
| 568 | CreateExponentialRepresentation(decimal_rep, exponent, negative, f+1); |
| 569 | |
| 570 | freedtoa(decimal_rep); |
| 571 | |
| 572 | return result; |
| 573 | } |
| 574 | |
| 575 | |
| 576 | char* DoubleToPrecisionCString(double value, int p) { |
| 577 | ASSERT(p >= 1 && p <= 21); |
| 578 | |
| 579 | bool negative = false; |
| 580 | if (value < 0) { |
| 581 | value = -value; |
| 582 | negative = true; |
| 583 | } |
| 584 | |
| 585 | // Find a sufficiently precise decimal representation of n. |
| 586 | int decimal_point; |
| 587 | int sign; |
| 588 | char* decimal_rep = dtoa(value, 2, p, &decimal_point, &sign, NULL); |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 589 | int decimal_rep_length = StrLength(decimal_rep); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 590 | ASSERT(decimal_rep_length <= p); |
| 591 | |
| 592 | int exponent = decimal_point - 1; |
| 593 | |
| 594 | char* result = NULL; |
| 595 | |
| 596 | if (exponent < -6 || exponent >= p) { |
| 597 | result = |
| 598 | CreateExponentialRepresentation(decimal_rep, exponent, negative, p); |
| 599 | } else { |
| 600 | // Use fixed notation. |
| 601 | // |
| 602 | // Leave room in the result for appending a minus, a period and in |
| 603 | // the case where decimal_point is not positive for a zero in |
| 604 | // front of the period. |
| 605 | unsigned result_size = (decimal_point <= 0) |
| 606 | ? -decimal_point + p + 3 |
| 607 | : p + 2; |
| 608 | StringBuilder builder(result_size + 1); |
| 609 | if (negative) builder.AddCharacter('-'); |
| 610 | if (decimal_point <= 0) { |
| 611 | builder.AddString("0."); |
| 612 | builder.AddPadding('0', -decimal_point); |
| 613 | builder.AddString(decimal_rep); |
| 614 | builder.AddPadding('0', p - decimal_rep_length); |
| 615 | } else { |
| 616 | const int m = Min(decimal_rep_length, decimal_point); |
| 617 | builder.AddSubstring(decimal_rep, m); |
| 618 | builder.AddPadding('0', decimal_point - decimal_rep_length); |
| 619 | if (decimal_point < p) { |
| 620 | builder.AddCharacter('.'); |
| 621 | const int extra = negative ? 2 : 1; |
| 622 | if (decimal_rep_length > decimal_point) { |
Steve Block | d0582a6 | 2009-12-15 09:54:21 +0000 | [diff] [blame] | 623 | const int len = StrLength(decimal_rep + decimal_point); |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 624 | const int n = Min(len, p - (builder.position() - extra)); |
| 625 | builder.AddSubstring(decimal_rep + decimal_point, n); |
| 626 | } |
| 627 | builder.AddPadding('0', extra + (p - builder.position())); |
| 628 | } |
| 629 | } |
| 630 | result = builder.Finalize(); |
| 631 | } |
| 632 | |
| 633 | freedtoa(decimal_rep); |
| 634 | return result; |
| 635 | } |
| 636 | |
| 637 | |
| 638 | char* DoubleToRadixCString(double value, int radix) { |
| 639 | ASSERT(radix >= 2 && radix <= 36); |
| 640 | |
| 641 | // Character array used for conversion. |
| 642 | static const char chars[] = "0123456789abcdefghijklmnopqrstuvwxyz"; |
| 643 | |
| 644 | // Buffer for the integer part of the result. 1024 chars is enough |
| 645 | // for max integer value in radix 2. We need room for a sign too. |
| 646 | static const int kBufferSize = 1100; |
| 647 | char integer_buffer[kBufferSize]; |
| 648 | integer_buffer[kBufferSize - 1] = '\0'; |
| 649 | |
| 650 | // Buffer for the decimal part of the result. We only generate up |
| 651 | // to kBufferSize - 1 chars for the decimal part. |
| 652 | char decimal_buffer[kBufferSize]; |
| 653 | decimal_buffer[kBufferSize - 1] = '\0'; |
| 654 | |
| 655 | // Make sure the value is positive. |
| 656 | bool is_negative = value < 0.0; |
| 657 | if (is_negative) value = -value; |
| 658 | |
| 659 | // Get the integer part and the decimal part. |
| 660 | double integer_part = floor(value); |
| 661 | double decimal_part = value - integer_part; |
| 662 | |
| 663 | // Convert the integer part starting from the back. Always generate |
| 664 | // at least one digit. |
| 665 | int integer_pos = kBufferSize - 2; |
| 666 | do { |
| 667 | integer_buffer[integer_pos--] = |
Steve Block | 3ce2e20 | 2009-11-05 08:53:23 +0000 | [diff] [blame] | 668 | chars[static_cast<int>(modulo(integer_part, radix))]; |
Steve Block | a7e24c1 | 2009-10-30 11:49:00 +0000 | [diff] [blame] | 669 | integer_part /= radix; |
| 670 | } while (integer_part >= 1.0); |
| 671 | // Sanity check. |
| 672 | ASSERT(integer_pos > 0); |
| 673 | // Add sign if needed. |
| 674 | if (is_negative) integer_buffer[integer_pos--] = '-'; |
| 675 | |
| 676 | // Convert the decimal part. Repeatedly multiply by the radix to |
| 677 | // generate the next char. Never generate more than kBufferSize - 1 |
| 678 | // chars. |
| 679 | // |
| 680 | // TODO(1093998): We will often generate a full decimal_buffer of |
| 681 | // chars because hitting zero will often not happen. The right |
| 682 | // solution would be to continue until the string representation can |
| 683 | // be read back and yield the original value. To implement this |
| 684 | // efficiently, we probably have to modify dtoa. |
| 685 | int decimal_pos = 0; |
| 686 | while ((decimal_part > 0.0) && (decimal_pos < kBufferSize - 1)) { |
| 687 | decimal_part *= radix; |
| 688 | decimal_buffer[decimal_pos++] = |
| 689 | chars[static_cast<int>(floor(decimal_part))]; |
| 690 | decimal_part -= floor(decimal_part); |
| 691 | } |
| 692 | decimal_buffer[decimal_pos] = '\0'; |
| 693 | |
| 694 | // Compute the result size. |
| 695 | int integer_part_size = kBufferSize - 2 - integer_pos; |
| 696 | // Make room for zero termination. |
| 697 | unsigned result_size = integer_part_size + decimal_pos; |
| 698 | // If the number has a decimal part, leave room for the period. |
| 699 | if (decimal_pos > 0) result_size++; |
| 700 | // Allocate result and fill in the parts. |
| 701 | StringBuilder builder(result_size + 1); |
| 702 | builder.AddSubstring(integer_buffer + integer_pos + 1, integer_part_size); |
| 703 | if (decimal_pos > 0) builder.AddCharacter('.'); |
| 704 | builder.AddSubstring(decimal_buffer, decimal_pos); |
| 705 | return builder.Finalize(); |
| 706 | } |
| 707 | |
| 708 | |
| 709 | } } // namespace v8::internal |