mirror of
https://github.com/ethereum/solidity
synced 2023-10-03 13:03:40 +00:00
122 lines
4.2 KiB
C++
122 lines
4.2 KiB
C++
/*
|
|
This file is part of solidity.
|
|
|
|
solidity 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.
|
|
|
|
solidity 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 solidity. If not, see <http://www.gnu.org/licenses/>.
|
|
*/
|
|
/**
|
|
* Contains an abstract base class representing a selection of pairs of elements from a collection
|
|
* and its concrete implementations.
|
|
*/
|
|
|
|
#pragma once
|
|
|
|
#include <cassert>
|
|
#include <tuple>
|
|
#include <vector>
|
|
|
|
namespace solidity::phaser
|
|
{
|
|
|
|
/**
|
|
* Abstract base class for selections of pairs elements from a collection.
|
|
*
|
|
* An instance of this class represents a specific method of selecting a set of pairs of elements
|
|
* from containers of arbitrary sizes. The selected pairs always point at a subset of the elements
|
|
* from the container but may indicate the same element more than once. The pairs themselves can
|
|
* repeat too. The selection may or may not be fixed - it's up to a specific implementation whether
|
|
* subsequent calls for the same container produce the same indices or not.
|
|
*
|
|
* Derived classes are meant to override the @a materialise() method.
|
|
* This method is expected to produce pairs of selected elements given the size of the collection.
|
|
*/
|
|
class PairSelection
|
|
{
|
|
public:
|
|
PairSelection() = default;
|
|
PairSelection(PairSelection const&) = delete;
|
|
PairSelection& operator=(PairSelection const&) = delete;
|
|
virtual ~PairSelection() = default;
|
|
|
|
virtual std::vector<std::tuple<size_t, size_t>> materialise(size_t _poolSize) const = 0;
|
|
};
|
|
|
|
/**
|
|
* A selection that selects pairs of random elements from a container. The resulting set of pairs
|
|
* may contain the same pair more than once but does not contain pairs of duplicates. Always
|
|
* selects as many pairs as the size of the container multiplied by @a _selectionSize (unless the
|
|
* container is empty).
|
|
*/
|
|
class RandomPairSelection: public PairSelection
|
|
{
|
|
public:
|
|
explicit RandomPairSelection(double _selectionSize):
|
|
m_selectionSize(_selectionSize) {}
|
|
|
|
std::vector<std::tuple<size_t, size_t>> materialise(size_t _poolSize) const override;
|
|
|
|
private:
|
|
double m_selectionSize;
|
|
};
|
|
|
|
|
|
/**
|
|
* A selection that goes over all elements in a container, for each one independently decides
|
|
* whether to select it or not and then randomly combines those elements into pairs. If the number
|
|
* of elements is odd, randomly decides whether to take one more or exclude one.
|
|
*
|
|
* Each element has the same chance of being selected and can be selected at most once.
|
|
* The number of selected elements is random and can be different with each call to
|
|
* @a materialise().
|
|
*/
|
|
class PairsFromRandomSubset: public PairSelection
|
|
{
|
|
public:
|
|
explicit PairsFromRandomSubset(double _selectionChance):
|
|
m_selectionChance(_selectionChance) {}
|
|
|
|
std::vector<std::tuple<size_t, size_t>> materialise(size_t _poolSize) const override;
|
|
|
|
private:
|
|
double m_selectionChance;
|
|
};
|
|
|
|
/**
|
|
* A selection that selects pairs of elements at specific, fixed positions indicated by a repeating
|
|
* "pattern". If the positions in the pattern exceed the size of the container, they are capped at
|
|
* the maximum available position. Always selects as many pairs as the size of the container
|
|
* multiplied by @a _selectionSize (unless the container is empty).
|
|
*
|
|
* E.g. if the pattern is {{0, 1}, {3, 9}} and collection size is 5, the selection will materialise
|
|
* into {{0, 1}, {3, 4}, {0, 1}, {3, 4}, {0, 1}}. If the size is 3, it will be
|
|
* {{0, 1}, {2, 2}, {0, 1}}.
|
|
*/
|
|
class PairMosaicSelection: public PairSelection
|
|
{
|
|
public:
|
|
explicit PairMosaicSelection(std::vector<std::tuple<size_t, size_t>> _pattern, double _selectionSize = 1.0):
|
|
m_pattern(move(_pattern)),
|
|
m_selectionSize(_selectionSize)
|
|
{
|
|
assert(m_pattern.size() > 0 || _selectionSize == 0.0);
|
|
}
|
|
|
|
std::vector<std::tuple<size_t, size_t>> materialise(size_t _poolSize) const override;
|
|
|
|
private:
|
|
std::vector<std::tuple<size_t, size_t>> m_pattern;
|
|
double m_selectionSize;
|
|
};
|
|
|
|
}
|