wallet/mpir_and_base58.cpp

#include "stdafx.h"
using ristretto255::hash, ristretto255::hsh, ristretto255::scalar, ristretto255::point;
namespace ro {
	//	fasthash fails at obliterating some forms of order in its input, but
	//	but this is OK, because our inputs are random to start with, and
	//	all we care about is good mixing and dispersion of that randomness.
	uint32_t fasthash(uint64_t id, std::span<const uint64_t> sp) {
		static constexpr uint64_t two_to_the_64_divided_by_golden_ratio{ 11400714819323198485 };
		id *= two_to_the_64_divided_by_golden_ratio;
		for (auto x : sp) {
			id += x;
			id *= two_to_the_64_divided_by_golden_ratio; 	//mixes and disperses the bits.
		}
		return id ^ (id >> 32);
	}

	class charmap {
	public:
		std::array< char, 0x100> index{	0, };
		charmap() = delete;
		constexpr charmap(const char * p, const char * q) {
			while (unsigned int pu{ static_cast<unsigned char>(*p++) }) {
				assert(index[pu] == 0);
				index[pu] = *q++;
			}
			assert(*(p - 1) == '\0' && *q == '\0');	
			/*	when an instance of this class is declared constexpr,
				an assert does not trigger a run time error,
				because expression evaluated at compile time.
				Instead the compiler reports that the expression
				did not evaluate to a constant,
				
				The error is confusing, because the error points to
				the declaration where the initialization was invoked,
				instead of pointing to the assert.
			*/
		}
	};

	class charmapWithFixup {
	public:
		std::array< char, 0x100> index{ 0, };
		charmapWithFixup() = delete;
		constexpr charmapWithFixup(const char* p, const char* q) {
			while (unsigned int pu{ static_cast<unsigned char>(*p++) }) {
				assert(index[pu] == 0);
				index[pu] = *q++;
			}
			index['I'] = index['l']='0';
			assert(*(p - 1) == '\0' && *q == '\0');
			/*	when an instance of this class is declared constexpr,
				an assert does not trigger a run time error,
				because expression evaluated at compile time.
				Instead the compiler reports that the expression
				did not evaluate to a constant,

				The error is confusing, because the error points to
				the declaration where the initialization was invoked,
				instead of pointing to the assert.
			*/
		}
	};


	//template <> class base58<scalar> : public CompileSizedString<44> {};
	static_assert(sizeof(base58<point>) == 46, "base58 point strings unexpected size");

	static constexpr char index2cryptoBase58[]	{ "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz" };
	static constexpr char index2MpirBase58[]	{ "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuv" };

	void map_base_from_mpir58(char* p) {
		static constexpr charmap map(index2MpirBase58, index2cryptoBase58);
		while (uint8_t pu{ static_cast<uint8_t>(*p) }) {
			*p++ = map.index[pu];
		}
	}

	void map_base_to_mpir58(const char* p, char* q, size_t count) {
		static constexpr charmap map(index2cryptoBase58, index2MpirBase58);
		static_assert(map.index[0xF0] == 0);
		while (count--) {
			unsigned int pu{ static_cast<unsigned char>(*p++) };
			char c{ map.index[pu] };
			if (c == '\0') throw NotBase58Exception();
			*q++ = c;
		}
		*q = '\0';
	}

	//	If the string does not fill the space, pushes it rightwards
	//	and pads with leading zeroes.
	void right_justify_string(char* p, char* terminal_null) {
		char* x = p;
		for (; *x && x < terminal_null; x++) {
		}
		if (x != terminal_null) {
			assert(x < terminal_null);
			memmove(terminal_null - x + p, p, x - p);
			memset(p, '0', terminal_null - x);
			*terminal_null = '\0';
		}
		else assert(*terminal_null == '\0');
	}
}


namespace mpir {
	mpz ristretto25519_curve_order("1000000000000000000000000000000014def9dea2f79cd65812631a5cf5d3ed", 16);
}

/*
thread_local std::unique_ptr<thread_local__> thl2{ std::make_unique<thread_local__>() };  //Destructor is not called
std::unique_ptr<thread_local__> thl2{ std::make_unique<thread_local__>() };  //Destructor is called
looks like cannot use smart pointers with thread_local
The destructor will not be called on thread_local variables
The machinery of classes just does not work with thread local variables.
A thread local variable can only be defined outside of the stack,
its destructor will probably not be called, and there are whimsical,
arbitrary, and incomprehensible restrictions on its constructor
*/

//	The class thread_locall__, which holds all my thread_local global values
//	has to be explicitly constructed in code with new
//	and explicitly with delete destructed at program
//	termination
//	Because the compiler will not generate code
//	for construction and destruction of thread_local
//	values.
thread_local thread_local__* thl{ nullptr };