109 lines
2.2 KiB
C++
109 lines
2.2 KiB
C++
#include "big_int.hpp"
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#include "tl/expected.hpp"
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#include <iostream>
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#include <charconv>
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#include <vector>
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inline uint8_t hex(char c) {
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switch(c) {
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case '0': return 0;
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case '1': return 1;
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case '2': return 2;
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case '3': return 3;
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case '4': return 4;
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case '5': return 5;
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case '6': return 6;
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case '7': return 7;
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case '8': return 8;
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case '9': return 9;
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case 'a': return 10;
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case 'b': return 11;
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case 'c': return 12;
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case 'd': return 13;
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case 'e': return 14;
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case 'f': return 15;
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case 'A': return 10;
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case 'B': return 11;
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case 'C': return 12;
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case 'D': return 13;
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case 'E': return 14;
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case 'F': return 15;
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default:
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return 0xff;
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}
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}
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tl::expected<BigInt,BigInt::eError>
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BigInt::from_string(const std::string& str) {
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BigInt b;
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// std::cout << str << std::endl;
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uint8_t hval=0;
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uint8_t nibble;
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size_t i = str.size()+1;
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for(auto c : str) {
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nibble = hex(c);
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if (nibble ==0xFF) {
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return tl::make_unexpected(eError::PARSE_ERROR);
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}
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if (i%2) {
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hval = nibble << 4;
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} else {
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hval |= nibble;
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b.data[256 - (i/2)]= hval;
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hval = 0;
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}
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i--;
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}
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// std::cout << std::hex;
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// for (auto b: b.data)
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// {
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// std::cout << (int)b;
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// }
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// std::cout << std::dec << std::endl;
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return b;
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}
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BigInt BigInt::from_int(uint64_t value)
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{
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BigInt b;
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b.data[248]=(value >> 56 & 0xff);
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b.data[249]=(value >> 48 & 0xff);
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b.data[250]=(value >> 40 & 0xff);
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b.data[251]=(value >> 32 & 0xff);
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b.data[252]=(value >> 24 & 0xff);
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b.data[253]=(value >> 16 & 0xff);
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b.data[254]=(value >> 8 & 0xff);
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b.data[255]=(value & 0xff);
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return b;
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}
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constexpr char hex_char [] = "0123456789abcdef";
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std::string BigInt::to_string() const
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{
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std::string s;
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uint8_t b;
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uint8_t first_digit = 0;
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for (size_t i = 0; i<256;i++) {
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b = data[i];
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if (first_digit==0) {
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if (b==0) {
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continue;
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} else if (b>0xf) {
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s.push_back(hex_char[b >> 4]);
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}
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s.push_back(hex_char[b & 0xf]);
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first_digit = b;
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} else {
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s.push_back(hex_char[b >> 4]);
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s.push_back(hex_char[b & 0xf]);
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}
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}
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return s;
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}
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bool operator == (const BigInt& rhs, const BigInt& lhs)
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{ return rhs.data == lhs.data; }
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