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-rw-r--r-- | security/sandbox/chromium/base/third_party/double_conversion/double-conversion/bignum.h | 152 |
1 files changed, 152 insertions, 0 deletions
diff --git a/security/sandbox/chromium/base/third_party/double_conversion/double-conversion/bignum.h b/security/sandbox/chromium/base/third_party/double_conversion/double-conversion/bignum.h new file mode 100644 index 0000000000..14d1ca86fc --- /dev/null +++ b/security/sandbox/chromium/base/third_party/double_conversion/double-conversion/bignum.h @@ -0,0 +1,152 @@ +// 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. + +#ifndef DOUBLE_CONVERSION_BIGNUM_H_ +#define DOUBLE_CONVERSION_BIGNUM_H_ + +#include "utils.h" + +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 + +#endif // DOUBLE_CONVERSION_BIGNUM_H_ |