#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> {
	public:
		charmap() = delete;
		constexpr charmap(const char* p, const char* q) {
			while (unsigned int pu{ static_cast<unsigned char>(*p++) }) {
				assert((*this)[pu] == 0);
				(*this)[pu] = *q++;
			}
			assert(*(p - 1) == '\0' && *q == '\0');
		}
	};

	//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 const charmap map(index2MpirBase58, index2cryptoBase58);
		while (unsigned int pu{ static_cast<unsigned char>(*p) }) {
			*p++ = map[pu];
		}
	}

	void map_base_to_mpir58(const char* p, char* q, size_t count) {
		static const charmap map(index2cryptoBase58, index2MpirBase58);
		while (count--) {
			unsigned int pu{ static_cast<unsigned char>(*p++) };
			char c{ map[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');
	}
}