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/*
* Copyright (C) 2017 Caio Lima <ticaiolima@gmail.com>
*
* 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 "ExceptionHelpers.h"
#include "JSObject.h"
#include "ParseInt.h"
#include <wtf/CagedPtr.h>
#include <wtf/text/StringBuilder.h>
#include <wtf/text/StringView.h>
#include <wtf/text/WTFString.h>
namespace JSC {
class JSBigInt final : public JSCell {
using Base = JSCell;
static const unsigned StructureFlags = Base::StructureFlags | OverridesToThis;
public:
JSBigInt(VM&, Structure*, int length);
enum class InitializationType { None, WithZero };
void initialize(InitializationType);
static void visitChildren(JSCell*, SlotVisitor&);
static size_t estimatedSize(JSCell*);
static size_t allocationSize(int length);
static Structure* createStructure(VM&, JSGlobalObject*, JSValue prototype);
static JSBigInt* createZero(VM&);
static JSBigInt* createWithLength(VM&, int length);
static JSBigInt* createFrom(VM&, int32_t value);
static JSBigInt* createFrom(VM&, uint32_t value);
static JSBigInt* createFrom(VM&, int64_t value);
static JSBigInt* createFrom(VM&, bool value);
DECLARE_EXPORT_INFO;
void finishCreation(VM&);
JSValue toPrimitive(ExecState*, PreferredPrimitiveType) const;
void setSign(bool sign) { m_sign = sign; }
bool sign() const { return m_sign; }
void setLength(int length) { m_length = length; }
int length() const { return m_length; }
static JSBigInt* parseInt(ExecState*, VM&, StringView, uint8_t radix);
static JSBigInt* parseInt(ExecState*, StringView);
std::optional<uint8_t> singleDigitValueForString();
String toString(ExecState&, int radix);
JS_EXPORT_PRIVATE static bool equals(JSBigInt*, JSBigInt*);
bool getPrimitiveNumber(ExecState*, double& number, JSValue& result) const;
double toNumber(ExecState*) const;
JSObject* toObject(ExecState*, JSGlobalObject*) const;
private:
using Digit = uintptr_t;
static constexpr const int bitsPerByte = 8;
static constexpr const int digitBits = sizeof(Digit) * bitsPerByte;
static constexpr const int halfDigitBits = digitBits / 2;
static constexpr const Digit halfDigitMask = (1ull << halfDigitBits) - 1;
static constexpr const int maxInt = 0x7FFFFFFF;
// The maximum length that the current implementation supports would be
// maxInt / digitBits. However, we use a lower limit for now, because
// raising it later is easier than lowering it.
// Support up to 1 million bits.
static const int maxLength = 1024 * 1024 / (sizeof(void*) * bitsPerByte);
static uint64_t calculateMaximumCharactersRequired(int length, int radix, Digit lastDigit, bool sign);
static void absoluteDivSmall(ExecState&, JSBigInt* x, Digit divisor, JSBigInt** quotient, Digit& remainder);
static void internalMultiplyAdd(JSBigInt* source, Digit factor, Digit summand, int, JSBigInt* result);
// Digit arithmetic helpers.
static Digit digitAdd(Digit a, Digit b, Digit& carry);
static Digit digitSub(Digit a, Digit b, Digit& borrow);
static Digit digitMul(Digit a, Digit b, Digit& high);
static Digit digitDiv(Digit high, Digit low, Digit divisor, Digit& remainder);
static Digit digitPow(Digit base, Digit exponent);
static String toStringGeneric(ExecState&, JSBigInt*, int radix);
bool isZero();
template <typename CharType>
static JSBigInt* parseInt(ExecState*, CharType* data, int length);
template <typename CharType>
static JSBigInt* parseInt(ExecState*, VM&, CharType* data, int length, int startIndex, int radix, bool allowEmptyString = true);
static JSBigInt* allocateFor(ExecState*, VM&, int radix, int charcount);
JSBigInt* rightTrim(VM&);
void inplaceMultiplyAdd(Digit multiplier, Digit part);
static size_t offsetOfData();
Digit* dataStorage();
Digit digit(int);
void setDigit(int, Digit);
int m_length;
bool m_sign;
};
inline JSBigInt* asBigInt(JSValue value)
{
ASSERT(value.asCell()->isBigInt());
return jsCast<JSBigInt*>(value.asCell());
}
} // namespace JSC