RGBCube/serenity
1
Fork 0
mirror of https://github.com/RGBCube/serenity synced 2025-07-25 18:27:35 +00:00
Code Issues Activity Actions

LibCrypto: Add base-10 string de/serialization methods for bigint

Browse source
This commit is contained in:
Itamar 2020-04-09 17:09:11 +03:00 • committed by Andreas Kling
parent 709c691f38
commit 2125a4debb
3 changed files with 67 additions and 2 deletions
Download patch file Download diff file Expand all files Collapse all files

36
Libraries/LibCrypto/BigInt/UnsignedBigInteger.cpp
View file

@ -25,9 +25,45 @@
*/
#include "UnsignedBigInteger.h"
#include <AK/StringBuilder.h>
namespace Crypto {
UnsignedBigInteger UnsignedBigInteger::from_base10(const String& str)
{
UnsignedBigInteger result;
for (auto& c : str) {
result = result.multiply({ 10 }).add(c - '0');
}
return result;
}
String UnsignedBigInteger::to_base10() const
{
StringBuilder builder;
UnsignedBigInteger temp(*this);
while (temp != UnsignedBigInteger { 0 }) {
auto div_result = temp.divide({ 10 });
ASSERT(div_result.remainder.words()[0] < 10);
builder.append(static_cast<char>(div_result.remainder.words()[0] + '0'));
temp = div_result.quotient;
}
auto reversed_string = builder.to_string();
builder.clear();
for (int i = reversed_string.length() - 1; i >= 0; --i) {
builder.append(reversed_string[i]);
}
return builder.to_string();
}
bool UnsignedBigInteger::operator!=(const UnsignedBigInteger& other) const
{
return !(*this == other);
}
/**
* Complexity: O(N) where N is the number of words in the larger number
*/

8
Libraries/LibCrypto/BigInt/UnsignedBigInteger.h
View file

@ -26,6 +26,7 @@
#pragma once
#include <AK/LogStream.h>
#include <AK/String.h>
#include <AK/Types.h>
#include <AK/Vector.h>
@ -44,6 +45,7 @@ public:
UnsignedBigInteger() {}
static UnsignedBigInteger from_base10(const String& str);
static UnsignedBigInteger create_invalid();
const AK::Vector<u32>& words() const { return m_words; }
@ -63,11 +65,14 @@ public:
size_t trimmed_length() const;
bool operator==(const UnsignedBigInteger& other) const;
bool operator!=(const UnsignedBigInteger& other) const;
bool operator<(const UnsignedBigInteger& other) const;
void invalidate() { m_is_invalid = true; }
bool is_invalid() const { return m_is_invalid; }
String to_base10() const;
private:
UnsignedBigInteger shift_left_by_n_words(const size_t number_of_words) const;
u32 shift_left_get_one_word(const size_t num_bits, const size_t result_word_index) const;
@ -86,7 +91,8 @@ struct UnsignedDivisionResult {
}
inline const LogStream& operator<<(const LogStream& stream, const Crypto::UnsignedBigInteger value)
inline const LogStream&
operator<<(const LogStream& stream, const Crypto::UnsignedBigInteger value)
{
if (value.is_invalid()) {
stream << "Invalid BigInt";