68 lines
2.3 KiB
C++
68 lines
2.3 KiB
C++
#include "stdafx.h"
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using ristretto255::hash, ristretto255::hsh, ristretto255::scalar, ristretto255::point;
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namespace ro {
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// fasthash fails at obliterating some forms of order in its input, but
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// but this is OK, because our inputs are random to start with, and
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// all we care about is good mixing and dispersion of that randomness.
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uint32_t fasthash(uint64_t id, std::span<const uint64_t> sp) {
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static constexpr uint64_t two_to_the_64_divided_by_golden_ratio{ 11400714819323198485 };
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id *= two_to_the_64_divided_by_golden_ratio;
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for (auto x : sp) {
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id += x;
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id *= two_to_the_64_divided_by_golden_ratio; //mixes and disperses the bits.
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}
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return id ^ (id >> 32);
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}
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class charmap :public std::array<char, 0x100> {
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public:
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charmap() = delete;
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constexpr charmap(const char* p, const char* q) {
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while (unsigned int pu{ static_cast<unsigned char>(*p++) }) {
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assert((*this)[pu] == 0);
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(*this)[pu] = *q++;
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}
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assert(*(p - 1) == '\0' && *q == '\0');
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}
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};
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//template <> class base58<scalar> : public CompileSizedString<44> {};
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static_assert(sizeof(base58<point>) == 46, "base58 point strings unexpected size");
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static constexpr char index2cryptoBase58[]{ "123456789ABCDEFGHJKLMNPQRSTUVWXYZabcdefghijkmnopqrstuvwxyz" };
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static constexpr char index2MpirBase58[]{ "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuv" };
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void map_base_from_mpir58(char* p) {
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static const charmap map(index2MpirBase58, index2cryptoBase58);
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while (unsigned int pu{ static_cast<unsigned char>(*p) }) {
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*p++ = map[pu];
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}
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}
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void map_base_to_mpir58(const char* p, char* q, size_t count) {
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static const charmap map(index2cryptoBase58, index2MpirBase58);
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while (count--) {
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unsigned int pu{ static_cast<unsigned char>(*p++) };
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char c{ map[pu] };
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if (c == '\0') throw NotBase58Exception();
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*q++ = c;
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}
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*q = '\0';
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}
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// If the string does not fill the space, pushes it rightwards
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// and pads with leading zeroes.
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void right_justify_string(char* p, char* terminal_null) {
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char* x = p;
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for (; *x && x < terminal_null; x++) {
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}
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if (x != terminal_null) {
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assert(x < terminal_null);
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memmove(terminal_null - x + p, p, x - p);
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memset(p, '0', terminal_null - x);
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*terminal_null = '\0';
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}
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else assert(*terminal_null == '\0');
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}
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}
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