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// © 2018 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html
//
// From the double-conversion library. Original license:
//
// Copyright 2010 the V8 project authors. All rights reserved.
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright
// notice, this list of conditions and the following disclaimer.
// * 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.
// * Neither the name of Google Inc. nor the names of its
// contributors may be used to endorse or promote products derived
// from this software without specific prior written permission.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
// "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 THE COPYRIGHT
// OWNER 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.
// ICU PATCH: ifdef around UCONFIG_NO_FORMATTING
#include "unicode/utypes.h"
#if !UCONFIG_NO_FORMATTING
#ifndef DOUBLE_CONVERSION_BIGNUM_H_
#define DOUBLE_CONVERSION_BIGNUM_H_
// ICU PATCH: Customize header file paths for ICU.
#include "double-conversion-utils.h"
// ICU PATCH: Wrap in ICU namespace
U_NAMESPACE_BEGIN
namespace double_conversion {
class Bignum {
public:
// 3584 = 128 * 28. We can represent 2^3584 > 10^1000 accurately.
// This bignum can encode much bigger numbers, since it contains an
// exponent.
static const int kMaxSignificantBits = 3584;
Bignum() : used_bigits_(0), exponent_(0) {}
void AssignUInt16(const uint16_t value);
void AssignUInt64(uint64_t value);
void AssignBignum(const Bignum& other);
void AssignDecimalString(const Vector<const char> value);
void AssignHexString(const Vector<const char> value);
void AssignPowerUInt16(uint16_t base, const int exponent);
void AddUInt64(const uint64_t operand);
void AddBignum(const Bignum& other);
// Precondition: this >= other.
void SubtractBignum(const Bignum& other);
void Square();
void ShiftLeft(const int shift_amount);
void MultiplyByUInt32(const uint32_t factor);
void MultiplyByUInt64(const uint64_t factor);
void MultiplyByPowerOfTen(const int exponent);
void Times10() { return MultiplyByUInt32(10); }
// Pseudocode:
// int result = this / other;
// this = this % other;
// In the worst case this function is in O(this/other).
uint16_t DivideModuloIntBignum(const Bignum& other);
bool ToHexString(char* buffer, const int buffer_size) const;
// Returns
// -1 if a < b,
// 0 if a == b, and
// +1 if a > b.
static int Compare(const Bignum& a, const Bignum& b);
static bool Equal(const Bignum& a, const Bignum& b) {
return Compare(a, b) == 0;
}
static bool LessEqual(const Bignum& a, const Bignum& b) {
return Compare(a, b) <= 0;
}
static bool Less(const Bignum& a, const Bignum& b) {
return Compare(a, b) < 0;
}
// Returns Compare(a + b, c);
static int PlusCompare(const Bignum& a, const Bignum& b, const Bignum& c);
// Returns a + b == c
static bool PlusEqual(const Bignum& a, const Bignum& b, const Bignum& c) {
return PlusCompare(a, b, c) == 0;
}
// Returns a + b <= c
static bool PlusLessEqual(const Bignum& a, const Bignum& b, const Bignum& c) {
return PlusCompare(a, b, c) <= 0;
}
// Returns a + b < c
static bool PlusLess(const Bignum& a, const Bignum& b, const Bignum& c) {
return PlusCompare(a, b, c) < 0;
}
private:
typedef uint32_t Chunk;
typedef uint64_t DoubleChunk;
static const int kChunkSize = sizeof(Chunk) * 8;
static const int kDoubleChunkSize = sizeof(DoubleChunk) * 8;
// With bigit size of 28 we loose some bits, but a double still fits easily
// into two chunks, and more importantly we can use the Comba multiplication.
static const int kBigitSize = 28;
static const Chunk kBigitMask = (1 << kBigitSize) - 1;
// Every instance allocates kBigitLength chunks on the stack. Bignums cannot
// grow. There are no checks if the stack-allocated space is sufficient.
static const int kBigitCapacity = kMaxSignificantBits / kBigitSize;
static void EnsureCapacity(const int size) {
if (size > kBigitCapacity) {
DOUBLE_CONVERSION_UNREACHABLE();
}
}
void Align(const Bignum& other);
void Clamp();
bool IsClamped() const {
return used_bigits_ == 0 || RawBigit(used_bigits_ - 1) != 0;
}
void Zero() {
used_bigits_ = 0;
exponent_ = 0;
}
// Requires this to have enough capacity (no tests done).
// Updates used_bigits_ if necessary.
// shift_amount must be < kBigitSize.
void BigitsShiftLeft(const int shift_amount);
// BigitLength includes the "hidden" bigits encoded in the exponent.
int BigitLength() const { return used_bigits_ + exponent_; }
Chunk& RawBigit(const int index);
const Chunk& RawBigit(const int index) const;
Chunk BigitOrZero(const int index) const;
void SubtractTimes(const Bignum& other, const int factor);
// The Bignum's value is value(bigits_buffer_) * 2^(exponent_ * kBigitSize),
// where the value of the buffer consists of the lower kBigitSize bits of
// the first used_bigits_ Chunks in bigits_buffer_, first chunk has lowest
// significant bits.
int16_t used_bigits_;
int16_t exponent_;
Chunk bigits_buffer_[kBigitCapacity];
DOUBLE_CONVERSION_DISALLOW_COPY_AND_ASSIGN(Bignum);
};
} // namespace double_conversion
// ICU PATCH: Close ICU namespace
U_NAMESPACE_END
#endif // DOUBLE_CONVERSION_BIGNUM_H_
#endif // ICU PATCH: close #if !UCONFIG_NO_FORMATTING
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