1// Copyright 2011 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#ifndef V8_CONVERSIONS_H_ 29#define V8_CONVERSIONS_H_ 30 31#include "utils.h" 32 33namespace v8 { 34namespace internal { 35 36class UnicodeCache; 37 38// Maximum number of significant digits in decimal representation. 39// The longest possible double in decimal representation is 40// (2^53 - 1) * 2 ^ -1074 that is (2 ^ 53 - 1) * 5 ^ 1074 / 10 ^ 1074 41// (768 digits). If we parse a number whose first digits are equal to a 42// mean of 2 adjacent doubles (that could have up to 769 digits) the result 43// must be rounded to the bigger one unless the tail consists of zeros, so 44// we don't need to preserve all the digits. 45const int kMaxSignificantDigits = 772; 46 47 48inline bool isDigit(int x, int radix) { 49 return (x >= '0' && x <= '9' && x < '0' + radix) 50 || (radix > 10 && x >= 'a' && x < 'a' + radix - 10) 51 || (radix > 10 && x >= 'A' && x < 'A' + radix - 10); 52} 53 54 55inline bool isBinaryDigit(int x) { 56 return x == '0' || x == '1'; 57} 58 59 60// The fast double-to-(unsigned-)int conversion routine does not guarantee 61// rounding towards zero. 62// For NaN and values outside the int range, return INT_MIN or INT_MAX. 63inline int FastD2IChecked(double x) { 64 if (!(x >= INT_MIN)) return INT_MIN; // Negation to catch NaNs. 65 if (x > INT_MAX) return INT_MAX; 66 return static_cast<int>(x); 67} 68 69 70// The fast double-to-(unsigned-)int conversion routine does not guarantee 71// rounding towards zero. 72// The result is unspecified if x is infinite or NaN, or if the rounded 73// integer value is outside the range of type int. 74inline int FastD2I(double x) { 75 return static_cast<int>(x); 76} 77 78inline unsigned int FastD2UI(double x); 79 80 81inline double FastI2D(int x) { 82 // There is no rounding involved in converting an integer to a 83 // double, so this code should compile to a few instructions without 84 // any FPU pipeline stalls. 85 return static_cast<double>(x); 86} 87 88 89inline double FastUI2D(unsigned x) { 90 // There is no rounding involved in converting an unsigned integer to a 91 // double, so this code should compile to a few instructions without 92 // any FPU pipeline stalls. 93 return static_cast<double>(x); 94} 95 96 97// This function should match the exact semantics of ECMA-262 9.4. 98inline double DoubleToInteger(double x); 99 100 101// This function should match the exact semantics of ECMA-262 9.5. 102inline int32_t DoubleToInt32(double x); 103 104 105// This function should match the exact semantics of ECMA-262 9.6. 106inline uint32_t DoubleToUint32(double x) { 107 return static_cast<uint32_t>(DoubleToInt32(x)); 108} 109 110 111// Enumeration for allowing octals and ignoring junk when converting 112// strings to numbers. 113enum ConversionFlags { 114 NO_FLAGS = 0, 115 ALLOW_HEX = 1, 116 ALLOW_OCTAL = 2, 117 ALLOW_IMPLICIT_OCTAL = 4, 118 ALLOW_BINARY = 8, 119 ALLOW_TRAILING_JUNK = 16 120}; 121 122 123// Converts a string into a double value according to ECMA-262 9.3.1 124double StringToDouble(UnicodeCache* unicode_cache, 125 Vector<const char> str, 126 int flags, 127 double empty_string_val = 0); 128double StringToDouble(UnicodeCache* unicode_cache, 129 Vector<const uc16> str, 130 int flags, 131 double empty_string_val = 0); 132// This version expects a zero-terminated character array. 133double StringToDouble(UnicodeCache* unicode_cache, 134 const char* str, 135 int flags, 136 double empty_string_val = 0); 137 138const int kDoubleToCStringMinBufferSize = 100; 139 140// Converts a double to a string value according to ECMA-262 9.8.1. 141// The buffer should be large enough for any floating point number. 142// 100 characters is enough. 143const char* DoubleToCString(double value, Vector<char> buffer); 144 145// Convert an int to a null-terminated string. The returned string is 146// located inside the buffer, but not necessarily at the start. 147const char* IntToCString(int n, Vector<char> buffer); 148 149// Additional number to string conversions for the number type. 150// The caller is responsible for calling free on the returned pointer. 151char* DoubleToFixedCString(double value, int f); 152char* DoubleToExponentialCString(double value, int f); 153char* DoubleToPrecisionCString(double value, int f); 154char* DoubleToRadixCString(double value, int radix); 155 156} } // namespace v8::internal 157 158#endif // V8_CONVERSIONS_H_ 159