Files
mines/zano/libdevcore/FixedHash.h

339 lines
9.9 KiB
C++

/*
This file is part of progminer.
progminer is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
progminer is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with progminer. If not, see <http://www.gnu.org/licenses/>.
*/
/** @file FixedHash.h
* @author Gav Wood <i@gavwood.com>
* @date 2014
*
* The FixedHash fixed-size "hash" container type.
*/
#pragma once
#include <algorithm>
#include <array>
#include <cstdint>
#include <random>
#include "CommonData.h"
namespace dev
{
extern std::random_device s_fixedHashEngine;
/// Fixed-size raw-byte array container type, with an API optimised for storing hashes.
/// Transparently converts to/from the corresponding arithmetic type; this will
/// assume the data contained in the hash is big-endian.
template <unsigned N>
class FixedHash
{
public:
#if defined(_WIN32)
const char* k_ellipsis = "...";
#else
const char* k_ellipsis = "\342\200\246";
#endif
/// The corresponding arithmetic type.
using Arith = boost::multiprecision::number<boost::multiprecision::cpp_int_backend<N * 8, N * 8,
boost::multiprecision::unsigned_magnitude, boost::multiprecision::unchecked, void>>;
/// The size of the container.
enum
{
size = N
};
/// A dummy flag to avoid accidental construction from pointer.
enum ConstructFromPointerType
{
ConstructFromPointer
};
/// Method to convert from a string.
enum ConstructFromHashType
{
AlignLeft,
AlignRight,
FailIfDifferent
};
/// Construct an empty hash.
FixedHash() { m_data.fill(0); }
/// Construct from another hash, filling with zeroes or cropping as necessary.
template <unsigned M>
explicit FixedHash(FixedHash<M> const& _h, ConstructFromHashType _t = AlignLeft)
{
m_data.fill(0);
unsigned c = std::min(M, N);
for (unsigned i = 0; i < c; ++i)
m_data[_t == AlignRight ? N - 1 - i : i] = _h[_t == AlignRight ? M - 1 - i : i];
}
/// Convert from the corresponding arithmetic type.
FixedHash(Arith const& _arith) { toBigEndian(_arith, m_data); }
/// Convert from unsigned
explicit FixedHash(unsigned _u) { toBigEndian(_u, m_data); }
/// Explicitly construct, copying from a byte array.
explicit FixedHash(bytes const& _b, ConstructFromHashType _t = FailIfDifferent)
{
if (_b.size() == N)
memcpy(m_data.data(), _b.data(), std::min<unsigned>(_b.size(), N));
else
{
m_data.fill(0);
if (_t != FailIfDifferent)
{
auto c = std::min<unsigned>(_b.size(), N);
for (unsigned i = 0; i < c; ++i)
m_data[_t == AlignRight ? N - 1 - i : i] =
_b[_t == AlignRight ? _b.size() - 1 - i : i];
}
}
}
/// Explicitly construct, copying from a byte array.
explicit FixedHash(bytesConstRef _b, ConstructFromHashType _t = FailIfDifferent)
{
if (_b.size() == N)
memcpy(m_data.data(), _b.data(), std::min<unsigned>(_b.size(), N));
else
{
m_data.fill(0);
if (_t != FailIfDifferent)
{
auto c = std::min<unsigned>(_b.size(), N);
for (unsigned i = 0; i < c; ++i)
m_data[_t == AlignRight ? N - 1 - i : i] =
_b[_t == AlignRight ? _b.size() - 1 - i : i];
}
}
}
/// Explicitly construct, copying from a bytes in memory with given pointer.
explicit FixedHash(byte const* _bs, ConstructFromPointerType /*unused*/)
{
memcpy(m_data.data(), _bs, N);
}
/// Explicitly construct, copying from a string.
explicit FixedHash(std::string const& _s)
: FixedHash(fromHex(_s, WhenError::Throw), FailIfDifferent)
{}
/// Convert to arithmetic type.
operator Arith() const { return fromBigEndian<Arith>(m_data); }
/// @returns true iff this is the empty hash.
explicit operator bool() const
{
return std::any_of(m_data.begin(), m_data.end(), [](byte _b) { return _b != 0; });
}
// The obvious comparison operators.
bool operator==(FixedHash const& _c) const { return m_data == _c.m_data; }
bool operator!=(FixedHash const& _c) const { return m_data != _c.m_data; }
bool operator<(FixedHash const& _c) const
{
for (unsigned i = 0; i < N; ++i)
{
if (m_data[i] < _c.m_data[i])
return true;
if (m_data[i] > _c.m_data[i])
return false;
}
return false;
}
bool operator>=(FixedHash const& _c) const { return !operator<(_c); }
bool operator<=(FixedHash const& _c) const { return operator==(_c) || operator<(_c); }
bool operator>(FixedHash const& _c) const { return !operator<=(_c); }
// The obvious binary operators.
FixedHash& operator^=(FixedHash const& _c)
{
for (unsigned i = 0; i < N; ++i)
m_data[i] ^= _c.m_data[i];
return *this;
}
FixedHash operator^(FixedHash const& _c) const { return FixedHash(*this) ^= _c; }
FixedHash& operator|=(FixedHash const& _c)
{
for (unsigned i = 0; i < N; ++i)
m_data[i] |= _c.m_data[i];
return *this;
}
FixedHash operator|(FixedHash const& _c) const { return FixedHash(*this) |= _c; }
FixedHash& operator&=(FixedHash const& _c)
{
for (unsigned i = 0; i < N; ++i)
m_data[i] &= _c.m_data[i];
return *this;
}
FixedHash operator&(FixedHash const& _c) const { return FixedHash(*this) &= _c; }
FixedHash operator~() const
{
FixedHash ret;
for (unsigned i = 0; i < N; ++i)
ret[i] = ~m_data[i];
return ret;
}
// Big-endian increment.
FixedHash& operator++()
{
for (unsigned i = size; i > 0 && !++m_data[--i];)
{
}
return *this;
}
/// @returns a particular byte from the hash.
byte& operator[](unsigned _i) { return m_data[_i]; }
/// @returns a particular byte from the hash.
byte operator[](unsigned _i) const { return m_data[_i]; }
/// @returns an abridged version of the hash as a user-readable hex string.
std::string abridged() const { return toHex(ref().cropped(0, 4)) + k_ellipsis; }
/// @returns the hash as a user-readable hex string.
std::string hex(HexPrefix _prefix = HexPrefix::DontAdd) const { return toHex(ref(), 2, _prefix); }
/// @returns a mutable byte vector_ref to the object's data.
bytesRef ref() { return bytesRef(m_data.data(), N); }
/// @returns a constant byte vector_ref to the object's data.
bytesConstRef ref() const { return bytesConstRef(m_data.data(), N); }
/// @returns a mutable byte pointer to the object's data.
byte* data() { return m_data.data(); }
/// @returns a constant byte pointer to the object's data.
byte const* data() const { return m_data.data(); }
/// Populate with random data.
template <class Engine>
void randomize(Engine& _eng)
{
for (auto& i : m_data)
i = (uint8_t)std::uniform_int_distribution<uint16_t>(0, 255)(_eng);
}
/// @returns a random valued object.
static FixedHash random()
{
FixedHash ret;
ret.randomize(s_fixedHashEngine);
return ret;
}
struct hash
{
/// Make a hash of the object's data.
size_t operator()(FixedHash const& _value) const
{
return boost::hash_range(_value.m_data.cbegin(), _value.m_data.cend());
}
};
void clear() { m_data.fill(0); }
private:
std::array<byte, N> m_data; ///< The binary data.
};
/// Fast equality operator for h256.
template <>
inline bool FixedHash<32>::operator==(FixedHash<32> const& _other) const
{
const uint64_t* hash1 = (const uint64_t*)data();
const uint64_t* hash2 = (const uint64_t*)_other.data();
return (hash1[0] == hash2[0]) && (hash1[1] == hash2[1]) && (hash1[2] == hash2[2]) &&
(hash1[3] == hash2[3]);
}
/// Fast std::hash compatible hash function object for h256.
template <>
inline size_t FixedHash<32>::hash::operator()(FixedHash<32> const& value) const
{
uint64_t const* data = reinterpret_cast<uint64_t const*>(value.data());
return boost::hash_range(data, data + 4);
}
/// Stream I/O for the FixedHash class.
template <unsigned N>
inline std::ostream& operator<<(std::ostream& _out, FixedHash<N> const& _h)
{
_out << std::noshowbase << std::hex << std::setfill('0');
for (unsigned i = 0; i < N; ++i)
_out << std::setw(2) << (int)_h[i];
_out << std::dec;
return _out;
}
// Common types of FixedHash.
using h2048 = FixedHash<256>;
using h1024 = FixedHash<128>;
using h520 = FixedHash<65>;
using h512 = FixedHash<64>;
using h256 = FixedHash<32>;
using h160 = FixedHash<20>;
using h128 = FixedHash<16>;
using h64 = FixedHash<8>;
using h512s = std::vector<h512>;
using h256s = std::vector<h256>;
using h160s = std::vector<h160>;
inline std::string toString(h256s const& _bs)
{
std::ostringstream out;
out << "[ ";
for (auto i : _bs)
out << i.abridged() << ", ";
out << "]";
return out.str();
}
} // namespace dev
namespace std
{
/// Forward std::hash<dev::FixedHash> to dev::FixedHash::hash.
template <>
struct hash<dev::h64> : dev::h64::hash
{
};
template <>
struct hash<dev::h128> : dev::h128::hash
{
};
template <>
struct hash<dev::h160> : dev::h160::hash
{
};
template <>
struct hash<dev::h256> : dev::h256::hash
{
};
template <>
struct hash<dev::h512> : dev::h512::hash
{
};
} // namespace std