solidity/libyul/YulString.h
2018-11-09 15:40:36 +01:00

105 lines
2.4 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/>.
*/
/**
* String abstraction that avoids copies.
*/
#pragma once
#include <boost/noncopyable.hpp>
#include <map>
#include <memory>
#include <vector>
#include <string>
namespace dev
{
namespace yul
{
class YulStringRepository: boost::noncopyable
{
public:
YulStringRepository()
{
reset();
}
static YulStringRepository& instance()
{
static YulStringRepository inst;
return inst;
}
size_t stringToId(std::string const& _string)
{
if (_string.empty())
return 0;
size_t& id = m_ids[_string];
if (id == 0)
{
m_strings.emplace_back(std::make_shared<std::string>(_string));
id = m_strings.size() - 1;
}
return id;
}
std::string const& idToString(size_t _id) const
{
return *m_strings.at(_id);
}
void reset()
{
m_strings.clear();
m_ids.clear();
m_strings.emplace_back(std::make_shared<std::string>());
m_ids[std::string{}] = 0;
}
private:
std::vector<std::shared_ptr<std::string>> m_strings;
std::map<std::string, size_t> m_ids;
};
class YulString
{
public:
YulString() = default;
explicit YulString(std::string const& _s): m_id(YulStringRepository::instance().stringToId(_s)) {}
YulString(YulString const&) = default;
YulString(YulString&&) = default;
YulString& operator=(YulString const&) = default;
YulString& operator=(YulString&&) = default;
/// This is not consistent with the string <-operator!
bool operator<(YulString const& _other) const { return m_id < _other.m_id; }
bool operator==(YulString const& _other) const { return m_id == _other.m_id; }
bool operator!=(YulString const& _other) const { return m_id != _other.m_id; }
bool empty() const { return m_id == 0; }
std::string const& str() const
{
return YulStringRepository::instance().idToString(m_id);
}
private:
/// ID of the string. Assumes that the empty string has ID zero.
size_t m_id = 0;
};
}
}