source: src/Common/ScopedMap.h@ db70fe4

//
// Cforall Version 1.0.0 Copyright (C) 2015 University of Waterloo
//
// The contents of this file are covered under the licence agreement in the
// file "LICENCE" distributed with Cforall.
//
// ScopedMap.h --
//
// Author           : Aaron B. Moss
// Created On       : Wed Dec 2 11:37:00 2015
// Last Modified By : Peter A. Buhr
// Last Modified On : Fri Jul 21 22:18:24 2017
// Update Count     : 2
//

#pragma once

#include <cassert>
#include <iterator>
#include <map>
#include <utility>
#include <vector>

/// A map where the items are placed into nested scopes;
/// inserted items are placed into the innermost scope, lookup looks from the innermost scope outward
template<typename Key, typename Value>
class ScopedMap {
        typedef std::map< Key, Value > Scope;
        typedef std::vector< Scope > ScopeList;

        ScopeList scopes; ///< scoped list of maps
public:
        typedef typename Scope::key_type key_type;
        typedef typename Scope::mapped_type mapped_type;
        typedef typename Scope::value_type value_type;
        typedef typename ScopeList::size_type size_type;
        typedef typename ScopeList::difference_type difference_type;
        typedef typename Scope::reference reference;
        typedef typename Scope::const_reference const_reference;
        typedef typename Scope::pointer pointer;
        typedef typename Scope::const_pointer const_pointer;

        class iterator : public std::iterator< std::bidirectional_iterator_tag,
                                               value_type > {
        friend class ScopedMap;
        friend class const_iterator;
                typedef typename std::map< Key, Value >::iterator wrapped_iterator;
                typedef typename std::vector< std::map< Key, Value > > scope_list;
                typedef typename scope_list::size_type size_type;

                /// Checks if this iterator points to a valid item
                bool is_valid() const {
                        return it != (*scopes)[level].end();
                }

                /// Increments on invalid
                iterator& next_valid() {
                        if ( ! is_valid() ) { ++(*this); }
                        return *this;
                }

                /// Decrements on invalid
                iterator& prev_valid() {
                        if ( ! is_valid() ) { --(*this); }
                        return *this;
                }

                iterator(scope_list &_scopes, const wrapped_iterator &_it, size_type inLevel)
                        : scopes(&_scopes), it(_it), level(inLevel) {}
        public:
                iterator(const iterator &that) : scopes(that.scopes), it(that.it), level(that.level) {}
                iterator& operator= (const iterator &that) {
                        scopes = that.scopes; level = that.level; it = that.it;
                        return *this;
                }

                reference operator* () { return *it; }
                pointer operator-> () { return it.operator->(); }

                iterator& operator++ () {
                        if ( it == (*scopes)[level].end() ) {
                                if ( level == 0 ) return *this;
                                --level;
                                it = (*scopes)[level].begin();
                        } else {
                                ++it;
                        }
                        return next_valid();
                }
                iterator operator++ (int) { iterator tmp = *this; ++(*this); return tmp; }

                iterator& operator-- () {
                        // may fail if this is the begin iterator; allowed by STL spec
                        if ( it == (*scopes)[level].begin() ) {
                                ++level;
                                it = (*scopes)[level].end();
                        }
                        --it;
                        return prev_valid();
                }
                iterator operator-- (int) { iterator tmp = *this; --(*this); return tmp; }

                bool operator== (const iterator &that) const {
                        return scopes == that.scopes && level == that.level && it == that.it;
                }
                bool operator!= (const iterator &that) const { return !( *this == that ); }

                size_type get_level() const { return level; }

        private:
                scope_list *scopes;
                wrapped_iterator it;
                size_type level;
        };

        class const_iterator : public std::iterator< std::bidirectional_iterator_tag,
                                                     value_type > {
        friend class ScopedMap;
                typedef typename std::map< Key, Value >::iterator wrapped_iterator;
                typedef typename std::map< Key, Value >::const_iterator wrapped_const_iterator;
                typedef typename std::vector< std::map< Key, Value > > scope_list;
                typedef typename scope_list::size_type size_type;

                /// Checks if this iterator points to a valid item
                bool is_valid() const {
                        return it != (*scopes)[level].end();
                }

                /// Increments on invalid
                const_iterator& next_valid() {
                        if ( ! is_valid() ) { ++(*this); }
                        return *this;
                }

                /// Decrements on invalid
                const_iterator& prev_valid() {
                        if ( ! is_valid() ) { --(*this); }
                        return *this;
                }

                const_iterator(scope_list const &_scopes, const wrapped_const_iterator &_it, size_type inLevel)
                        : scopes(&_scopes), it(_it), level(inLevel) {}
        public:
                const_iterator(const iterator &that) : scopes(that.scopes), it(that.it), level(that.level) {}
                const_iterator(const const_iterator &that) : scopes(that.scopes), it(that.it), level(that.level) {}
                const_iterator& operator= (const iterator &that) {
                        scopes = that.scopes; level = that.level; it = that.it;
                        return *this;
                }
                const_iterator& operator= (const const_iterator &that) {
                        scopes = that.scopes; level = that.level; it = that.it;
                        return *this;
                }

                const_reference operator* () { return *it; }
                const_pointer operator-> () { return it.operator->(); }

                const_iterator& operator++ () {
                        if ( it == (*scopes)[level].end() ) {
                                if ( level == 0 ) return *this;
                                --level;
                                it = (*scopes)[level].begin();
                        } else {
                                ++it;
                        }
                        return next_valid();
                }
                const_iterator operator++ (int) { const_iterator tmp = *this; ++(*this); return tmp; }

                const_iterator& operator-- () {
                        // may fail if this is the begin iterator; allowed by STL spec
                        if ( it == (*scopes)[level].begin() ) {
                                ++level;
                                it = (*scopes)[level].end();
                        }
                        --it;
                        return prev_valid();
                }
                const_iterator operator-- (int) { const_iterator tmp = *this; --(*this); return tmp; }

                bool operator== (const const_iterator &that) const {
                        return scopes == that.scopes && level == that.level && it == that.it;
                }
                bool operator!= (const const_iterator &that) const { return !( *this == that ); }

                size_type get_level() const { return level; }

        private:
                scope_list const *scopes;
                wrapped_const_iterator it;
                size_type level;
        };

        /// Starts a new scope
        void beginScope() {
                scopes.emplace_back();
        }

        /// Ends a scope; invalidates any iterators pointing to elements of that scope
        void endScope() {
                scopes.pop_back();
                assert( ! scopes.empty() );
        }

        /// Default constructor initializes with one scope
        ScopedMap() { beginScope(); }

        iterator begin() { return iterator(scopes, scopes.back().begin(), currentScope()).next_valid(); }
        const_iterator begin() const { return const_iterator(scopes, scopes.back().begin(), currentScope()).next_valid(); }
        const_iterator cbegin() const { return const_iterator(scopes, scopes.back().begin(), currentScope()).next_valid(); }
        iterator end() { return iterator(scopes, scopes[0].end(), 0); }
        const_iterator end() const { return const_iterator(scopes, scopes[0].end(), 0); }
        const_iterator cend() const { return const_iterator(scopes, scopes[0].end(), 0); }

        /// Gets the index of the current scope (counted from 1)
        size_type currentScope() const { return scopes.size() - 1; }

        /// Finds the given key in the outermost scope it occurs; returns end() for none such
        iterator find( const Key &key ) {
                for ( size_type i = scopes.size() - 1; ; --i ) {
                        typename Scope::iterator val = scopes[i].find( key );
                        if ( val != scopes[i].end() ) return iterator( scopes, val, i );
                        if ( i == 0 ) break;
                }
                return end();
        }
        const_iterator find( const Key &key ) const {
                        return const_iterator( const_cast< ScopedMap< Key, Value >* >(this)->find( key ) );
        }

        /// Finds the given key in the provided scope; returns end() for none such
        iterator findAt( size_type scope, const Key& key ) {
                typename Scope::iterator val = scopes[scope].find( key );
                if ( val != scopes[scope].end() ) return iterator( scopes, val, scope );
                return end();
        }
        const_iterator findAt( size_type scope, const Key& key ) const {
                return const_iterator( const_cast< ScopedMap< Key, Value >* >(this)->findAt( scope, key ) );
        }

        /// Finds the given key in the outermost scope inside the given scope where it occurs
        iterator findNext( const_iterator &it, const Key &key ) {
                if ( it.level == 0 ) return end();
                for ( size_type i = it.level - 1; ; --i ) {
                        typename Scope::iterator val = scopes[i].find( key );
                        if ( val != scopes[i].end() ) return iterator( scopes, val, i );
                        if ( i == 0 ) break;
                }
                return end();
        }
        const_iterator findNext( const_iterator &it, const Key &key ) const {
                        return const_iterator( const_cast< ScopedMap< Key, Value >* >(this)->findNext( it, key ) );
        }

        /// Inserts the given key-value pair into the outermost scope
        template< typename value_type_t >
        std::pair< iterator, bool > insert( value_type_t&& value ) {
                std::pair< typename Scope::iterator, bool > res = scopes.back().insert( std::forward<value_type_t>( value ) );
                return std::make_pair( iterator(scopes, std::move( res.first ), scopes.size()-1), std::move( res.second ) );
        }

        template< typename value_type_t >
        std::pair< iterator, bool > insert( iterator at, value_type_t&& value ) {
                Scope& scope = (*at.scopes) [ at.level ];
                std::pair< typename Scope::iterator, bool > res = scope.insert( std::forward<value_type_t>( value ) );
                return std::make_pair( iterator(scopes, std::move( res.first ), at.level), std::move( res.second ) );
        }

        template< typename value_t >
        std::pair< iterator, bool > insert( const Key &key, value_t&& value ) { return insert( std::make_pair( key, std::forward<value_t>( value ) ) ); }

        template< typename value_type_t >
        std::pair< iterator, bool > insertAt( size_type scope, value_type_t&& value ) {
                std::pair< typename Scope::iterator, bool > res = scopes.at(scope).insert( std::forward<value_type_t>( value ) );
                return std::make_pair( iterator(scopes, std::move( res.first ), scope), std::move( res.second ) );
        }

        Value& operator[] ( const Key &key ) {
                iterator slot = find( key );
                if ( slot != end() ) return slot->second;
                return insert( key, Value() ).first->second;
        }

        iterator erase( iterator pos ) {
                Scope& scope = (*pos.scopes) [ pos.level ];
                const typename iterator::wrapped_iterator& new_it = scope.erase( pos.it );
                iterator it( *pos.scopes, new_it, pos.level );
                return it.next_valid();
        }

        size_type count( const Key &key ) const {
                size_type c = 0;
                auto it = find( key );
                auto end = cend();

                while(it != end) {
                        c++;
                        it = findNext(it, key);
                }

                return c;
        }

};

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