mirror of
https://github.com/RGBCube/serenity
synced 2025-05-16 04:24:59 +00:00
fd80e7a339
We never really needed the 512 words in the first place, and this does reduce the stack allocations in montgomery modular power from 32Kb to a more manageable 2Kb :^) Note that the 32 words size doesn't provide any performance benefits or drawbacks compared to other values. All values seem to have equivalent performances (the tested values were 1, 2, 4, ..., 512). But since the previous value of 512 was definitely too big, let's reduce it for now!
115 lines
3.5 KiB
C++
115 lines
3.5 KiB
C++
/*
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* Copyright (c) 2020, Itamar S. <itamar8910@gmail.com>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#pragma once
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#include <AK/ByteBuffer.h>
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#include <AK/Span.h>
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#include <AK/String.h>
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#include <AK/Types.h>
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#include <AK/Vector.h>
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namespace Crypto {
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struct UnsignedDivisionResult;
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constexpr size_t STARTING_WORD_SIZE = 32;
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class UnsignedBigInteger {
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public:
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using Word = u32;
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static constexpr size_t BITS_IN_WORD = 32;
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UnsignedBigInteger(Word x) { m_words.append(x); }
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explicit UnsignedBigInteger(Vector<Word, STARTING_WORD_SIZE>&& words)
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: m_words(move(words))
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{
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}
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explicit UnsignedBigInteger(const u8* ptr, size_t length);
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UnsignedBigInteger() { }
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static UnsignedBigInteger create_invalid();
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static UnsignedBigInteger import_data(const StringView& data) { return import_data((const u8*)data.characters_without_null_termination(), data.length()); }
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static UnsignedBigInteger import_data(const u8* ptr, size_t length)
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{
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return UnsignedBigInteger(ptr, length);
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}
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size_t export_data(Bytes, bool remove_leading_zeros = false) const;
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static UnsignedBigInteger from_base10(const String& str);
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String to_base10() const;
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const Vector<Word, STARTING_WORD_SIZE>& words() const { return m_words; }
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void set_to_0();
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void set_to(Word other);
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void set_to(const UnsignedBigInteger& other);
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void invalidate()
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{
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m_is_invalid = true;
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m_cached_trimmed_length = {};
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}
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bool is_odd() const { return m_words.size() && (m_words[0] & 1); }
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bool is_invalid() const { return m_is_invalid; }
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size_t length() const { return m_words.size(); }
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// The "trimmed length" is the number of words after trimming leading zeroed words
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size_t trimmed_length() const;
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void clamp_to_trimmed_length();
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void resize_with_leading_zeros(size_t num_words);
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UnsignedBigInteger plus(const UnsignedBigInteger& other) const;
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UnsignedBigInteger minus(const UnsignedBigInteger& other) const;
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UnsignedBigInteger bitwise_or(const UnsignedBigInteger& other) const;
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UnsignedBigInteger bitwise_and(const UnsignedBigInteger& other) const;
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UnsignedBigInteger bitwise_xor(const UnsignedBigInteger& other) const;
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UnsignedBigInteger bitwise_not() const;
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UnsignedBigInteger shift_left(size_t num_bits) const;
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UnsignedBigInteger multiplied_by(const UnsignedBigInteger& other) const;
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UnsignedDivisionResult divided_by(const UnsignedBigInteger& divisor) const;
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void set_bit_inplace(size_t bit_index);
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bool operator==(const UnsignedBigInteger& other) const;
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bool operator!=(const UnsignedBigInteger& other) const;
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bool operator<(const UnsignedBigInteger& other) const;
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private:
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friend class UnsignedBigIntegerAlgorithms;
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// Little endian
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// m_word[0] + m_word[1] * Word::MAX + m_word[2] * Word::MAX * Word::MAX + ...
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Vector<Word, STARTING_WORD_SIZE> m_words;
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// Used to indicate a negative result, or a result of an invalid operation
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bool m_is_invalid { false };
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mutable Optional<size_t> m_cached_trimmed_length;
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};
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struct UnsignedDivisionResult {
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Crypto::UnsignedBigInteger quotient;
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Crypto::UnsignedBigInteger remainder;
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};
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}
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template<>
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struct AK::Formatter<Crypto::UnsignedBigInteger> : Formatter<StringView> {
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void format(FormatBuilder&, const Crypto::UnsignedBigInteger&);
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};
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inline Crypto::UnsignedBigInteger
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operator""_bigint(const char* string, size_t length)
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{
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return Crypto::UnsignedBigInteger::from_base10({ string, length });
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}
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