ager@chromium.org | a9aa5fa | 2011-04-13 08:46:07 +0000 | [diff] [blame] | 1 | // Copyright 2011 the V8 project authors. All rights reserved. |
christian.plesner.hansen | 43d26ec | 2008-07-03 15:10:15 +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_H_ |
| 29 | #define V8_CONVERSIONS_H_ |
| 30 | |
jkummerow@chromium.org | ddda9e8 | 2011-07-06 11:27:02 +0000 | [diff] [blame] | 31 | #include <limits> |
| 32 | |
ricow@chromium.org | 55ee807 | 2011-09-08 16:33:10 +0000 | [diff] [blame^] | 33 | #include "utils.h" |
ager@chromium.org | a9aa5fa | 2011-04-13 08:46:07 +0000 | [diff] [blame] | 34 | |
kasperl@chromium.org | 71affb5 | 2009-05-26 05:44:31 +0000 | [diff] [blame] | 35 | namespace v8 { |
| 36 | namespace internal { |
christian.plesner.hansen | 43d26ec | 2008-07-03 15:10:15 +0000 | [diff] [blame] | 37 | |
ricow@chromium.org | 55ee807 | 2011-09-08 16:33:10 +0000 | [diff] [blame^] | 38 | class UnicodeCache; |
| 39 | |
jkummerow@chromium.org | ddda9e8 | 2011-07-06 11:27:02 +0000 | [diff] [blame] | 40 | // Maximum number of significant digits in decimal representation. |
| 41 | // The longest possible double in decimal representation is |
| 42 | // (2^53 - 1) * 2 ^ -1074 that is (2 ^ 53 - 1) * 5 ^ 1074 / 10 ^ 1074 |
| 43 | // (768 digits). If we parse a number whose first digits are equal to a |
| 44 | // mean of 2 adjacent doubles (that could have up to 769 digits) the result |
| 45 | // must be rounded to the bigger one unless the tail consists of zeros, so |
| 46 | // we don't need to preserve all the digits. |
| 47 | const int kMaxSignificantDigits = 772; |
| 48 | |
jkummerow@chromium.org | ddda9e8 | 2011-07-06 11:27:02 +0000 | [diff] [blame] | 49 | |
jkummerow@chromium.org | 486075a | 2011-09-07 12:44:28 +0000 | [diff] [blame] | 50 | static inline bool isDigit(int x, int radix) { |
jkummerow@chromium.org | ddda9e8 | 2011-07-06 11:27:02 +0000 | [diff] [blame] | 51 | return (x >= '0' && x <= '9' && x < '0' + radix) |
| 52 | || (radix > 10 && x >= 'a' && x < 'a' + radix - 10) |
| 53 | || (radix > 10 && x >= 'A' && x < 'A' + radix - 10); |
| 54 | } |
| 55 | |
| 56 | |
jkummerow@chromium.org | 486075a | 2011-09-07 12:44:28 +0000 | [diff] [blame] | 57 | static inline double SignedZero(bool negative) { |
jkummerow@chromium.org | ddda9e8 | 2011-07-06 11:27:02 +0000 | [diff] [blame] | 58 | return negative ? -0.0 : 0.0; |
| 59 | } |
| 60 | |
ager@chromium.org | 3811b43 | 2009-10-28 14:53:37 +0000 | [diff] [blame] | 61 | |
ager@chromium.org | ce5e87b | 2010-03-10 10:24:18 +0000 | [diff] [blame] | 62 | // The fast double-to-(unsigned-)int conversion routine does not guarantee |
christian.plesner.hansen | 43d26ec | 2008-07-03 15:10:15 +0000 | [diff] [blame] | 63 | // rounding towards zero. |
| 64 | // The result is unspecified if x is infinite or NaN, or if the rounded |
| 65 | // integer value is outside the range of type int. |
kmillikin@chromium.org | 5d8f0e6 | 2010-03-24 08:21:20 +0000 | [diff] [blame] | 66 | static inline int FastD2I(double x) { |
| 67 | // The static_cast convertion from double to int used to be slow, but |
| 68 | // as new benchmarks show, now it is much faster than lrint(). |
| 69 | return static_cast<int>(x); |
| 70 | } |
| 71 | |
ager@chromium.org | ce5e87b | 2010-03-10 10:24:18 +0000 | [diff] [blame] | 72 | static inline unsigned int FastD2UI(double x); |
christian.plesner.hansen | 43d26ec | 2008-07-03 15:10:15 +0000 | [diff] [blame] | 73 | |
| 74 | |
| 75 | static inline double FastI2D(int x) { |
| 76 | // There is no rounding involved in converting an integer to a |
| 77 | // double, so this code should compile to a few instructions without |
| 78 | // any FPU pipeline stalls. |
| 79 | return static_cast<double>(x); |
| 80 | } |
| 81 | |
| 82 | |
| 83 | static inline double FastUI2D(unsigned x) { |
| 84 | // There is no rounding involved in converting an unsigned integer to a |
| 85 | // double, so this code should compile to a few instructions without |
| 86 | // any FPU pipeline stalls. |
| 87 | return static_cast<double>(x); |
| 88 | } |
| 89 | |
| 90 | |
| 91 | // This function should match the exact semantics of ECMA-262 9.4. |
| 92 | static inline double DoubleToInteger(double x); |
| 93 | |
| 94 | |
| 95 | // This function should match the exact semantics of ECMA-262 9.5. |
| 96 | static inline int32_t DoubleToInt32(double x); |
| 97 | |
| 98 | |
| 99 | // This function should match the exact semantics of ECMA-262 9.6. |
| 100 | static inline uint32_t DoubleToUint32(double x) { |
| 101 | return static_cast<uint32_t>(DoubleToInt32(x)); |
| 102 | } |
| 103 | |
| 104 | |
christian.plesner.hansen | 43d26ec | 2008-07-03 15:10:15 +0000 | [diff] [blame] | 105 | // Enumeration for allowing octals and ignoring junk when converting |
| 106 | // strings to numbers. |
| 107 | enum ConversionFlags { |
| 108 | NO_FLAGS = 0, |
| 109 | ALLOW_HEX = 1, |
| 110 | ALLOW_OCTALS = 2, |
| 111 | ALLOW_TRAILING_JUNK = 4 |
| 112 | }; |
| 113 | |
| 114 | |
christian.plesner.hansen | 43d26ec | 2008-07-03 15:10:15 +0000 | [diff] [blame] | 115 | // Converts a string into a double value according to ECMA-262 9.3.1 |
ager@chromium.org | a9aa5fa | 2011-04-13 08:46:07 +0000 | [diff] [blame] | 116 | double StringToDouble(UnicodeCache* unicode_cache, |
ager@chromium.org | a9aa5fa | 2011-04-13 08:46:07 +0000 | [diff] [blame] | 117 | Vector<const char> str, |
ricow@chromium.org | 65fae84 | 2010-08-25 15:26:24 +0000 | [diff] [blame] | 118 | int flags, |
| 119 | double empty_string_val = 0); |
danno@chromium.org | 40cb878 | 2011-05-25 07:58:50 +0000 | [diff] [blame] | 120 | double StringToDouble(UnicodeCache* unicode_cache, |
| 121 | Vector<const uc16> str, |
| 122 | int flags, |
| 123 | double empty_string_val = 0); |
ricow@chromium.org | 65fae84 | 2010-08-25 15:26:24 +0000 | [diff] [blame] | 124 | // This version expects a zero-terminated character array. |
ager@chromium.org | a9aa5fa | 2011-04-13 08:46:07 +0000 | [diff] [blame] | 125 | double StringToDouble(UnicodeCache* unicode_cache, |
| 126 | const char* str, |
| 127 | int flags, |
| 128 | double empty_string_val = 0); |
christian.plesner.hansen | 43d26ec | 2008-07-03 15:10:15 +0000 | [diff] [blame] | 129 | |
ricow@chromium.org | 55ee807 | 2011-09-08 16:33:10 +0000 | [diff] [blame^] | 130 | const int kDoubleToCStringMinBufferSize = 100; |
| 131 | |
christian.plesner.hansen | 43d26ec | 2008-07-03 15:10:15 +0000 | [diff] [blame] | 132 | // Converts a double to a string value according to ECMA-262 9.8.1. |
| 133 | // The buffer should be large enough for any floating point number. |
| 134 | // 100 characters is enough. |
| 135 | const char* DoubleToCString(double value, Vector<char> buffer); |
| 136 | |
| 137 | // Convert an int to a null-terminated string. The returned string is |
| 138 | // located inside the buffer, but not necessarily at the start. |
| 139 | const char* IntToCString(int n, Vector<char> buffer); |
| 140 | |
| 141 | // Additional number to string conversions for the number type. |
| 142 | // The caller is responsible for calling free on the returned pointer. |
| 143 | char* DoubleToFixedCString(double value, int f); |
| 144 | char* DoubleToExponentialCString(double value, int f); |
| 145 | char* DoubleToPrecisionCString(double value, int f); |
| 146 | char* DoubleToRadixCString(double value, int radix); |
| 147 | |
| 148 | } } // namespace v8::internal |
| 149 | |
| 150 | #endif // V8_CONVERSIONS_H_ |