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+/*
+ * Copyright (C) 2017 Apple Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ * 1. Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright
+ * notice, this list of conditions and the following disclaimer in the
+ * documentation and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+ * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+ * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+ * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+ * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+ * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
+ * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#pragma once
+
+#include "JSCJSValue.h"
+#include <wtf/dtoa.h>
+
+namespace JSC {
+
+static const double mantissaOverflowLowerBound = 9007199254740992.0;
+
+ALWAYS_INLINE static int parseDigit(unsigned short c, int radix)
+{
+ int digit = -1;
+
+ if (isASCIIDigit(c))
+ digit = c - '0';
+ else if (isASCIIUpper(c))
+ digit = c - 'A' + 10;
+ else if (isASCIILower(c))
+ digit = c - 'a' + 10;
+
+ if (digit >= radix)
+ return -1;
+ return digit;
+}
+
+static double parseIntOverflow(const LChar* s, unsigned length, int radix)
+{
+ double number = 0.0;
+ double radixMultiplier = 1.0;
+
+ for (const LChar* p = s + length - 1; p >= s; p--) {
+ if (radixMultiplier == std::numeric_limits<double>::infinity()) {
+ if (*p != '0') {
+ number = std::numeric_limits<double>::infinity();
+ break;
+ }
+ } else {
+ int digit = parseDigit(*p, radix);
+ number += digit * radixMultiplier;
+ }
+
+ radixMultiplier *= radix;
+ }
+
+ return number;
+}
+
+static double parseIntOverflow(const UChar* s, unsigned length, int radix)
+{
+ double number = 0.0;
+ double radixMultiplier = 1.0;
+
+ for (const UChar* p = s + length - 1; p >= s; p--) {
+ if (radixMultiplier == std::numeric_limits<double>::infinity()) {
+ if (*p != '0') {
+ number = std::numeric_limits<double>::infinity();
+ break;
+ }
+ } else {
+ int digit = parseDigit(*p, radix);
+ number += digit * radixMultiplier;
+ }
+
+ radixMultiplier *= radix;
+ }
+
+ return number;
+}
+
+static double parseIntOverflow(StringView string, int radix)
+{
+ if (string.is8Bit())
+ return parseIntOverflow(string.characters8(), string.length(), radix);
+ return parseIntOverflow(string.characters16(), string.length(), radix);
+}
+
+ALWAYS_INLINE static bool isStrWhiteSpace(UChar c)
+{
+ switch (c) {
+ // ECMA-262-5th 7.2 & 7.3
+ case 0x0009:
+ case 0x000A:
+ case 0x000B:
+ case 0x000C:
+ case 0x000D:
+ case 0x0020:
+ case 0x00A0:
+ case 0x180E: // This character used to be in Zs category before Unicode 6.3, and EcmaScript says that we should keep treating it as such.
+ case 0x2028:
+ case 0x2029:
+ case 0xFEFF:
+ return true;
+ default:
+ return c > 0xFF && u_charType(c) == U_SPACE_SEPARATOR;
+ }
+}
+
+// ES5.1 15.1.2.2
+template <typename CharType>
+ALWAYS_INLINE
+static double parseInt(StringView s, const CharType* data, int radix)
+{
+ // 1. Let inputString be ToString(string).
+ // 2. Let S be a newly created substring of inputString consisting of the first character that is not a
+ // StrWhiteSpaceChar and all characters following that character. (In other words, remove leading white
+ // space.) If inputString does not contain any such characters, let S be the empty string.
+ int length = s.length();
+ int p = 0;
+ while (p < length && isStrWhiteSpace(data[p]))
+ ++p;
+
+ // 3. Let sign be 1.
+ // 4. If S is not empty and the first character of S is a minus sign -, let sign be -1.
+ // 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.
+ double sign = 1;
+ if (p < length) {
+ if (data[p] == '+')
+ ++p;
+ else if (data[p] == '-') {
+ sign = -1;
+ ++p;
+ }
+ }
+
+ // 6. Let R = ToInt32(radix).
+ // 7. Let stripPrefix be true.
+ // 8. If R != 0,then
+ // b. If R != 16, let stripPrefix be false.
+ // 9. Else, R == 0
+ // a. LetR = 10.
+ // 10. If stripPrefix is true, then
+ // a. If the length of S is at least 2 and the first two characters of S are either ―0x or ―0X,
+ // then remove the first two characters from S and let R = 16.
+ // 11. If S contains any character that is not a radix-R digit, then let Z be the substring of S
+ // consisting of all characters before the first such character; otherwise, let Z be S.
+ if ((radix == 0 || radix == 16) && length - p >= 2 && data[p] == '0' && (data[p + 1] == 'x' || data[p + 1] == 'X')) {
+ radix = 16;
+ p += 2;
+ } else if (radix == 0)
+ radix = 10;
+
+ // 8.a If R < 2 or R > 36, then return NaN.
+ if (radix < 2 || radix > 36)
+ return PNaN;
+
+ // 13. Let mathInt be the mathematical integer value that is represented by Z in radix-R notation, using the letters
+ // A-Z and a-z for digits with values 10 through 35. (However, if R is 10 and Z contains more than 20 significant
+ // digits, every significant digit after the 20th may be replaced by a 0 digit, at the option of the implementation;
+ // and if R is not 2, 4, 8, 10, 16, or 32, then mathInt may be an implementation-dependent approximation to the
+ // mathematical integer value that is represented by Z in radix-R notation.)
+ // 14. Let number be the Number value for mathInt.
+ int firstDigitPosition = p;
+ bool sawDigit = false;
+ double number = 0;
+ while (p < length) {
+ int digit = parseDigit(data[p], radix);
+ if (digit == -1)
+ break;
+ sawDigit = true;
+ number *= radix;
+ number += digit;
+ ++p;
+ }
+
+ // 12. If Z is empty, return NaN.
+ if (!sawDigit)
+ return PNaN;
+
+ // Alternate code path for certain large numbers.
+ if (number >= mantissaOverflowLowerBound) {
+ if (radix == 10) {
+ size_t parsedLength;
+ number = parseDouble(s.substring(firstDigitPosition, p - firstDigitPosition), parsedLength);
+ } else if (radix == 2 || radix == 4 || radix == 8 || radix == 16 || radix == 32)
+ number = parseIntOverflow(s.substring(firstDigitPosition, p - firstDigitPosition), radix);
+ }
+
+ // 15. Return sign x number.
+ return sign * number;
+}
+
+ALWAYS_INLINE static double parseInt(StringView s, int radix)
+{
+ if (s.is8Bit())
+ return parseInt(s, s.characters8(), radix);
+ return parseInt(s, s.characters16(), radix);
+}
+
+template<typename CallbackWhenNoException>
+static ALWAYS_INLINE typename std::result_of<CallbackWhenNoException(StringView)>::type toStringView(ExecState* exec, JSValue value, CallbackWhenNoException callback)
+{
+ VM& vm = exec->vm();
+ auto scope = DECLARE_THROW_SCOPE(vm);
+ JSString* string = value.toStringOrNull(exec);
+ if (UNLIKELY(!string))
+ return { };
+ auto viewWithString = string->viewWithUnderlyingString(*exec);
+ RETURN_IF_EXCEPTION(scope, { });
+ return callback(viewWithString.view);
+}
+
+} // namespace JSC