lean2/src/util/splay_map.h

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/*
Copyright (c) 2013 Microsoft Corporation. All rights reserved.
Released under Apache 2.0 license as described in the file LICENSE.
Author: Leonardo de Moura
*/
#pragma once
#include <utility>
#include "util/pair.h"
#include "util/splay_tree.h"
namespace lean {
/**
\brief Wrapper for implementing maps using splay trees.
*/
template<typename K, typename T, typename CMP>
class splay_map : public CMP {
typedef std::pair<K, T> entry;
struct entry_cmp : public CMP {
entry_cmp(CMP const & c):CMP(c) {}
int operator()(entry const & e1, entry const & e2) const { return CMP::operator()(e1.first, e2.first); }
};
splay_tree<entry, entry_cmp> m_map;
public:
splay_map(CMP const & cmp = CMP()):m_map(entry_cmp(cmp)) {}
void swap(splay_map & m) { m_map.swap(m.m_map); }
bool empty() const { return m_map.empty(); }
void clear() { m_map.clear(); }
bool is_eqp(splay_map const & m) const { return m_map.is_eqp(m); }
unsigned size() const { return m_map.size(); }
void insert(K const & k, T const & v) { m_map.insert(mk_pair(k, v)); }
entry const * find(K const & k) const { return m_map.find(mk_pair(k, T())); }
bool contains(K const & k) const { return m_map.contains(mk_pair(k, T())); }
entry const * find_memoize(K const & k) { return m_map.contains(mk_pair(k, T())); }
void erase(K const & k) { m_map.erase(mk_pair(k, T())); }
class ref {
splay_map & m_map;
K const & m_key;
public:
ref(splay_map & m, K const & k):m_map(m), m_key(k) {}
ref & operator=(T const & v) { m_map.insert(m_key, v); return *this; }
operator T const &() {
entry const * e = m_map.find(m_key);
if (e) {
return e->second;
} else {
m_map.insert(m_key, T());
return m_map.find(m_key)->second;
}
}
};
/**
\brief Returns a reference to the value that is mapped to a key equivalent to key,
performing an insertion if such key does not already exist.
*/
ref operator[](K const & k) { return ref(*this, k); }
};
}