source: src/Common/ScopedMap.h @ 4bae7b4

//
// 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 : Tue Feb 15 08:41:28 2022
// Update Count     : 5
//

#pragma once

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

/// Default (empty) ScopedMap note type
struct EmptyNote {};

/// 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.
/// Scopes may be annotated with a value; the annotation defaults to empty
template<typename Key, typename Value, typename Note = EmptyNote>
class ScopedMap {
        typedef std::map< Key, Value > MapType;
        struct Scope {
                MapType map;
                Note note;

                template<typename N>
                Scope(N && n) : map(), note(std::forward<N>(n)) {}

                Scope() = default;
                Scope(const Scope &) = default;
                Scope(Scope &&) = default;
                Scope & operator= (const Scope &) = default;
                Scope & operator= (Scope &&) = default;
        };
        typedef std::vector< Scope > ScopeList;

        /// Scoped list of maps.
        ScopeList scopes;
public:
        typedef typename MapType::key_type key_type;
        typedef typename MapType::mapped_type mapped_type;
        typedef typename MapType::value_type value_type;
        typedef typename ScopeList::size_type size_type;
        typedef typename ScopeList::difference_type difference_type;
        typedef typename MapType::reference reference;
        typedef typename MapType::const_reference const_reference;
        typedef typename MapType::pointer pointer;
        typedef typename MapType::const_pointer const_pointer;

        // Both iterator types are complete bidrectional iterators, see below.
        class iterator;
        class const_iterator;

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

        // Starts a new scope with the given note
        template<typename N>
        void beginScope( N && n ) {
                scopes.emplace_back( std::forward<N>(n) );
        }

        /// 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() : scopes() { beginScope(); }

        /// Constructs with a given note on the outermost scope
        template<typename N>
        ScopedMap( N && n ) : scopes() { beginScope(std::forward<N>(n)); }

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

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

        /// Gets the note at the given scope
        Note & getNote() { return scopes.back().note; }
        const Note & getNote() const { return scopes.back().note; }
        Note & getNote( size_type i ) { return scopes[i].note; }
        const Note & getNote( size_type i ) const { return scopes[i].note; }

        /// 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 MapType::iterator val = scopes[i].map.find( key );
                        if ( val != scopes[i].map.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, Note >* >(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 MapType::iterator val = scopes[scope].map.find( key );
                if ( val != scopes[scope].map.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, Note >* >(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 MapType::iterator val = scopes[i].map.find( key );
                        if ( val != scopes[i].map.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, Note >* >(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 MapType::iterator, bool > res = scopes.back().map.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_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 MapType::iterator, bool > res = scopes.at(scope).map.insert( std::forward<value_type_t>( value ) );
                return std::make_pair( iterator(scopes, std::move( res.first ), scope), std::move( res.second ) );
        }

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

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

        /// Erases element with key in the innermost scope that has it.
        size_type erase( const Key & key ) {
                for ( auto it = scopes.rbegin() ; it != scopes.rend() ; ++it ) {
                        size_type i = it->map.erase( key );
                        if ( 0 != i ) return i;
                }
                return 0;
        }

        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;
        }

        bool contains( const Key & key ) const {
                return find( key ) != cend();
        }
};

template<typename Key, typename Value, typename Note>
class ScopedMap<Key, Value, Note>::iterator :
                public std::iterator< std::bidirectional_iterator_tag, value_type > {
        friend class ScopedMap;
        friend class const_iterator;
        typedef typename ScopedMap::MapType::iterator wrapped_iterator;
        typedef typename ScopedMap::ScopeList 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].map.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-> () const { return it.operator->(); }

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

        Note & get_note() { return (*scopes)[level].note; }
        const Note & get_note() const { return (*scopes)[level].note; }

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

template<typename Key, typename Value, typename Note>
class ScopedMap<Key, Value, Note>::const_iterator :
                public std::iterator< std::bidirectional_iterator_tag, value_type > {
        friend class ScopedMap;
        typedef typename ScopedMap::MapType::iterator wrapped_iterator;
        typedef typename ScopedMap::MapType::const_iterator wrapped_const_iterator;
        typedef typename ScopedMap::ScopeList 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].map.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].map.end() ) {
                        if ( level == 0 ) return *this;
                        --level;
                        it = (*scopes)[level].map.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].map.begin() ) {
                        ++level;
                        it = (*scopes)[level].map.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; }

        const Note & get_note() const { return (*scopes)[level].note; }

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

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// tab-width: 4 //
// mode: c++ //
// compile-command: "make install" //
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