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/*
* Copyright (C) 2017 Caio Lima <ticaiolima@gmail.com>
* Copyright (C) 2019 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 "CPU.h"
#include "ExceptionHelpers.h"
#include "JSObject.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 constexpr unsigned StructureFlags = Base::StructureFlags | StructureIsImmortal | OverridesToThis;
friend class CachedBigInt;
public:
JSBigInt(VM&, Structure*, unsigned length);
enum class InitializationType { None, WithZero };
void initialize(InitializationType);
static size_t estimatedSize(JSCell*, VM&);
static Structure* createStructure(VM&, JSGlobalObject*, JSValue prototype);
static JSBigInt* createZero(VM&);
static JSBigInt* tryCreateWithLength(ExecState*, unsigned length);
static JSBigInt* createWithLengthUnchecked(VM&, unsigned 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);
static size_t offsetOfLength()
{
return OBJECT_OFFSETOF(JSBigInt, m_length);
}
DECLARE_EXPORT_INFO;
JSValue toPrimitive(ExecState*, PreferredPrimitiveType) const;
void setSign(bool sign) { m_sign = sign; }
bool sign() const { return m_sign; }
unsigned length() const { return m_length; }
enum class ErrorParseMode {
ThrowExceptions,
IgnoreExceptions
};
enum class ParseIntMode { DisallowEmptyString, AllowEmptyString };
enum class ParseIntSign { Unsigned, Signed };
static JSBigInt* parseInt(ExecState*, VM&, StringView, uint8_t radix, ErrorParseMode = ErrorParseMode::ThrowExceptions, ParseIntSign = ParseIntSign::Unsigned);
static JSBigInt* parseInt(ExecState*, StringView, ErrorParseMode = ErrorParseMode::ThrowExceptions);
static JSBigInt* stringToBigInt(ExecState*, StringView);
static String tryGetString(VM&, JSBigInt*, unsigned radix);
Optional<uint8_t> singleDigitValueForString();
String toString(ExecState*, unsigned radix);
enum class ComparisonMode {
LessThan,
LessThanOrEqual
};
enum class ComparisonResult {
Equal,
Undefined,
GreaterThan,
LessThan
};
JS_EXPORT_PRIVATE static bool equals(JSBigInt*, JSBigInt*);
bool equalsToNumber(JSValue);
static ComparisonResult compare(JSBigInt* x, JSBigInt* y);
bool getPrimitiveNumber(ExecState*, double& number, JSValue& result) const;
double toNumber(ExecState*) const;
JSObject* toObject(ExecState*, JSGlobalObject*) const;
inline bool toBoolean() const { return !isZero(); }
static JSBigInt* exponentiate(ExecState*, JSBigInt* base, JSBigInt* exponent);
static JSBigInt* multiply(ExecState*, JSBigInt* x, JSBigInt* y);
ComparisonResult static compareToDouble(JSBigInt* x, double y);
static JSBigInt* add(ExecState*, JSBigInt* x, JSBigInt* y);
static JSBigInt* sub(ExecState*, JSBigInt* x, JSBigInt* y);
static JSBigInt* divide(ExecState*, JSBigInt* x, JSBigInt* y);
static JSBigInt* remainder(ExecState*, JSBigInt* x, JSBigInt* y);
static JSBigInt* unaryMinus(VM&, JSBigInt* x);
static JSBigInt* bitwiseAnd(ExecState*, JSBigInt* x, JSBigInt* y);
static JSBigInt* bitwiseOr(ExecState*, JSBigInt* x, JSBigInt* y);
static JSBigInt* bitwiseXor(ExecState*, JSBigInt* x, JSBigInt* y);
static JSBigInt* bitwiseNot(ExecState*, JSBigInt* x);
static JSBigInt* leftShift(ExecState*, JSBigInt* x, JSBigInt* y);
static JSBigInt* signedRightShift(ExecState*, JSBigInt* x, JSBigInt* y);
private:
using Digit = UCPURegister;
static constexpr unsigned bitsPerByte = 8;
static constexpr unsigned digitBits = sizeof(Digit) * bitsPerByte;
static constexpr unsigned halfDigitBits = digitBits / 2;
static constexpr Digit halfDigitMask = (1ull << halfDigitBits) - 1;
static constexpr 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 constexpr unsigned maxLength = 1024 * 1024 / (sizeof(void*) * bitsPerByte);
static constexpr unsigned maxLengthBits = maxInt - sizeof(void*) * bitsPerByte - 1;
static uint64_t calculateMaximumCharactersRequired(unsigned length, unsigned radix, Digit lastDigit, bool sign);
static ComparisonResult absoluteCompare(JSBigInt* x, JSBigInt* y);
static void absoluteDivWithDigitDivisor(VM&, JSBigInt* x, Digit divisor, JSBigInt** quotient, Digit& remainder);
static void internalMultiplyAdd(JSBigInt* source, Digit factor, Digit summand, unsigned, JSBigInt* result);
static void multiplyAccumulate(JSBigInt* multiplicand, Digit multiplier, JSBigInt* accumulator, unsigned accumulatorIndex);
static void absoluteDivWithBigIntDivisor(ExecState*, JSBigInt* dividend, JSBigInt* divisor, JSBigInt** quotient, JSBigInt** remainder);
enum class LeftShiftMode {
SameSizeResult,
AlwaysAddOneDigit
};
static JSBigInt* absoluteLeftShiftAlwaysCopy(ExecState*, JSBigInt* x, unsigned shift, LeftShiftMode);
static bool productGreaterThan(Digit factor1, Digit factor2, Digit high, Digit low);
Digit absoluteInplaceAdd(JSBigInt* summand, unsigned startIndex);
Digit absoluteInplaceSub(JSBigInt* subtrahend, unsigned startIndex);
void inplaceRightShift(unsigned shift);
enum class ExtraDigitsHandling {
Copy,
Skip
};
enum class SymmetricOp {
Symmetric,
NotSymmetric
};
template<typename BitwiseOp>
static JSBigInt* absoluteBitwiseOp(VM&, JSBigInt* x, JSBigInt* y, ExtraDigitsHandling, SymmetricOp, BitwiseOp&&);
static JSBigInt* absoluteAnd(VM&, JSBigInt* x, JSBigInt* y);
static JSBigInt* absoluteOr(VM&, JSBigInt* x, JSBigInt* y);
static JSBigInt* absoluteAndNot(VM&, JSBigInt* x, JSBigInt* y);
static JSBigInt* absoluteXor(VM&, JSBigInt* x, JSBigInt* y);
enum class SignOption {
Signed,
Unsigned
};
static JSBigInt* absoluteAddOne(ExecState*, JSBigInt* x, SignOption);
static JSBigInt* absoluteSubOne(ExecState*, JSBigInt* x, unsigned resultLength);
// 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 toStringBasePowerOfTwo(VM&, ExecState*, JSBigInt*, unsigned radix);
static String toStringGeneric(VM&, ExecState*, JSBigInt*, unsigned radix);
inline bool isZero() const
{
ASSERT(length() || !sign());
return length() == 0;
}
template <typename CharType>
static JSBigInt* parseInt(ExecState*, CharType* data, unsigned length, ErrorParseMode);
template <typename CharType>
static JSBigInt* parseInt(ExecState*, VM&, CharType* data, unsigned length, unsigned startIndex, unsigned radix, ErrorParseMode, ParseIntSign = ParseIntSign::Signed, ParseIntMode = ParseIntMode::AllowEmptyString);
static JSBigInt* allocateFor(ExecState*, VM&, unsigned radix, unsigned charcount);
static JSBigInt* copy(VM&, JSBigInt* x);
JSBigInt* rightTrim(VM&);
void inplaceMultiplyAdd(Digit multiplier, Digit part);
static JSBigInt* absoluteAdd(ExecState*, JSBigInt* x, JSBigInt* y, bool resultSign);
static JSBigInt* absoluteSub(VM&, JSBigInt* x, JSBigInt* y, bool resultSign);
static JSBigInt* leftShiftByAbsolute(ExecState*, JSBigInt* x, JSBigInt* y);
static JSBigInt* rightShiftByAbsolute(ExecState*, JSBigInt* x, JSBigInt* y);
static JSBigInt* rightShiftByMaximum(VM&, bool sign);
static Optional<Digit> toShiftAmount(JSBigInt* x);
inline static size_t allocationSize(unsigned length);
inline static size_t offsetOfData()
{
return WTF::roundUpToMultipleOf<sizeof(Digit)>(sizeof(JSBigInt));
}
inline Digit* dataStorage()
{
return bitwise_cast<Digit*>(reinterpret_cast<char*>(this) + offsetOfData());
}
Digit digit(unsigned);
void setDigit(unsigned, Digit);
const unsigned m_length;
bool m_sign { false };
friend size_t cellSize(VM&, JSCell*);
};
inline size_t JSBigInt::allocationSize(unsigned length)
{
size_t sizeWithPadding = WTF::roundUpToMultipleOf<sizeof(size_t)>(sizeof(JSBigInt));
return sizeWithPadding + length * sizeof(Digit);
}
inline JSBigInt* asBigInt(JSValue value)
{
ASSERT(value.asCell()->isBigInt());
return jsCast<JSBigInt*>(value.asCell());
}
} // namespace JSC