1/*
2 * Copyright (C) 2017 Apple Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions
6 * are met:
7 * 1. Redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer.
9 * 2. Redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
16 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
17 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
18 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
19 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
20 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
21 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
23 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
24 */
25
26#pragma once
27
28#include "JSCJSValue.h"
29#include "Lexer.h"
30#include <wtf/dtoa.h>
31
32namespace JSC {
33
34static const double mantissaOverflowLowerBound = 9007199254740992.0;
35
36ALWAYS_INLINE static int parseDigit(unsigned short c, int radix)
37{
38 int digit = -1;
39
40 if (isASCIIDigit(c))
41 digit = c - '0';
42 else if (isASCIIUpper(c))
43 digit = c - 'A' + 10;
44 else if (isASCIILower(c))
45 digit = c - 'a' + 10;
46
47 if (digit >= radix)
48 return -1;
49 return digit;
50}
51
52static double parseIntOverflow(const LChar* s, unsigned length, int radix)
53{
54 double number = 0.0;
55 double radixMultiplier = 1.0;
56
57 for (const LChar* p = s + length - 1; p >= s; p--) {
58 if (radixMultiplier == std::numeric_limits<double>::infinity()) {
59 if (*p != '0') {
60 number = std::numeric_limits<double>::infinity();
61 break;
62 }
63 } else {
64 int digit = parseDigit(*p, radix);
65 number += digit * radixMultiplier;
66 }
67
68 radixMultiplier *= radix;
69 }
70
71 return number;
72}
73
74static double parseIntOverflow(const UChar* s, unsigned length, int radix)
75{
76 double number = 0.0;
77 double radixMultiplier = 1.0;
78
79 for (const UChar* p = s + length - 1; p >= s; p--) {
80 if (radixMultiplier == std::numeric_limits<double>::infinity()) {
81 if (*p != '0') {
82 number = std::numeric_limits<double>::infinity();
83 break;
84 }
85 } else {
86 int digit = parseDigit(*p, radix);
87 number += digit * radixMultiplier;
88 }
89
90 radixMultiplier *= radix;
91 }
92
93 return number;
94}
95
96static double parseIntOverflow(StringView string, int radix)
97{
98 if (string.is8Bit())
99 return parseIntOverflow(string.characters8(), string.length(), radix);
100 return parseIntOverflow(string.characters16(), string.length(), radix);
101}
102
103ALWAYS_INLINE static bool isStrWhiteSpace(UChar c)
104{
105 // https://tc39.github.io/ecma262/#sec-tonumber-applied-to-the-string-type
106 return Lexer<UChar>::isWhiteSpace(c) || Lexer<UChar>::isLineTerminator(c);
107}
108
109// ES5.1 15.1.2.2
110template <typename CharType>
111ALWAYS_INLINE
112static double parseInt(StringView s, const CharType* data, int radix)
113{
114 // 1. Let inputString be ToString(string).
115 // 2. Let S be a newly created substring of inputString consisting of the first character that is not a
116 // StrWhiteSpaceChar and all characters following that character. (In other words, remove leading white
117 // space.) If inputString does not contain any such characters, let S be the empty string.
118 int length = s.length();
119 int p = 0;
120 while (p < length && isStrWhiteSpace(data[p]))
121 ++p;
122
123 // 3. Let sign be 1.
124 // 4. If S is not empty and the first character of S is a minus sign -, let sign be -1.
125 // 5. If S is not empty and the first character of S is a plus sign + or a minus sign -, then remove the first character from S.
126 double sign = 1;
127 if (p < length) {
128 if (data[p] == '+')
129 ++p;
130 else if (data[p] == '-') {
131 sign = -1;
132 ++p;
133 }
134 }
135
136 // 6. Let R = ToInt32(radix).
137 // 7. Let stripPrefix be true.
138 // 8. If R != 0,then
139 // b. If R != 16, let stripPrefix be false.
140 // 9. Else, R == 0
141 // a. LetR = 10.
142 // 10. If stripPrefix is true, then
143 // a. If the length of S is at least 2 and the first two characters of S are either ―0x or ―0X,
144 // then remove the first two characters from S and let R = 16.
145 // 11. If S contains any character that is not a radix-R digit, then let Z be the substring of S
146 // consisting of all characters before the first such character; otherwise, let Z be S.
147 if ((radix == 0 || radix == 16) && length - p >= 2 && data[p] == '0' && (data[p + 1] == 'x' || data[p + 1] == 'X')) {
148 radix = 16;
149 p += 2;
150 } else if (radix == 0)
151 radix = 10;
152
153 // 8.a If R < 2 or R > 36, then return NaN.
154 if (radix < 2 || radix > 36)
155 return PNaN;
156
157 // 13. Let mathInt be the mathematical integer value that is represented by Z in radix-R notation, using the letters
158 // A-Z and a-z for digits with values 10 through 35. (However, if R is 10 and Z contains more than 20 significant
159 // digits, every significant digit after the 20th may be replaced by a 0 digit, at the option of the implementation;
160 // and if R is not 2, 4, 8, 10, 16, or 32, then mathInt may be an implementation-dependent approximation to the
161 // mathematical integer value that is represented by Z in radix-R notation.)
162 // 14. Let number be the Number value for mathInt.
163 int firstDigitPosition = p;
164 bool sawDigit = false;
165 double number = 0;
166 while (p < length) {
167 int digit = parseDigit(data[p], radix);
168 if (digit == -1)
169 break;
170 sawDigit = true;
171 number *= radix;
172 number += digit;
173 ++p;
174 }
175
176 // 12. If Z is empty, return NaN.
177 if (!sawDigit)
178 return PNaN;
179
180 // Alternate code path for certain large numbers.
181 if (number >= mantissaOverflowLowerBound) {
182 if (radix == 10) {
183 size_t parsedLength;
184 number = parseDouble(s.substring(firstDigitPosition, p - firstDigitPosition), parsedLength);
185 } else if (radix == 2 || radix == 4 || radix == 8 || radix == 16 || radix == 32)
186 number = parseIntOverflow(s.substring(firstDigitPosition, p - firstDigitPosition), radix);
187 }
188
189 // 15. Return sign x number.
190 return sign * number;
191}
192
193ALWAYS_INLINE static double parseInt(StringView s, int radix)
194{
195 if (s.is8Bit())
196 return parseInt(s, s.characters8(), radix);
197 return parseInt(s, s.characters16(), radix);
198}
199
200template<typename CallbackWhenNoException>
201static ALWAYS_INLINE typename std::result_of<CallbackWhenNoException(StringView)>::type toStringView(ExecState* exec, JSValue value, CallbackWhenNoException callback)
202{
203 VM& vm = exec->vm();
204 auto scope = DECLARE_THROW_SCOPE(vm);
205 JSString* string = value.toStringOrNull(exec);
206 EXCEPTION_ASSERT(!!scope.exception() == !string);
207 if (UNLIKELY(!string))
208 return { };
209 auto viewWithString = string->viewWithUnderlyingString(exec);
210 RETURN_IF_EXCEPTION(scope, { });
211 RELEASE_AND_RETURN(scope, callback(viewWithString.view));
212}
213
214// Mapping from integers 0..35 to digit identifying this value, for radix 2..36.
215const char radixDigits[] = "0123456789abcdefghijklmnopqrstuvwxyz";
216
217} // namespace JSC
218