source: src/Common/VectorMap.h@ ee897e4b

//
// 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 Feb  1 16:55:00 2017
// Last Modified By : Aaron B. Moss
// Last Modified On : Wed Feb  1 16:55:00 2017
// Update Count     : 1
//

#ifndef _VECTORMAP_H
#define _VECTORMAP_H

#include <iterator>
#include <utility>
#include <vector>

/// Maps integers from a contiguous range to T's
template<typename T>
class VectorMap {
        std::vector<T> data;

public:
        typedef typename std::vector<T>::size_type size_type;
        typedef size_type key_type;
        typedef T mapped_type;
        typedef std::pair<size_type, T&> value_type;
        typedef std::pair<size_type, const T&> const_value_type;
        typedef typename std::vector<T>::difference_type difference_type;
        typedef const value_type& reference;
        typedef const const_value_type& const_reference;
        typedef const value_type* pointer;
        typedef const const_value_type* const_pointer;
        
        class iterator : public std::iterator< std::bidirectional_iterator_tag,
                                               value_type,
                                                                                    difference_type,
                                                                                        pointer,
                                                                                        reference > {
        friend class VectorMap;
        friend class const_iterator;
        
                value_type data;

                iterator(size_type i, std::vector<T>& v) : data(i, v[i]) {}
        public:
                iterator(const iterator& that) : data(that.data) {}
                iterator& operator= (const iterator& that) {
                        new(&data) value_type{ that.data };
                        return *this;
                }

                reference operator* () { return data; }
                pointer operator-> () { return &data; }

                iterator& operator++ () {
                        // SHENANIGANS: relies on pair<unsigned, T&> having a trivial destructor and
                        // vector<T> having contiguous layout
                        new(&data) value_type{ (data.first + 1), *(&data.second + 1) };
                        return *this;
                }
                iterator operator++ (int) { iterator tmp = *this; ++(*this); return tmp; }

                iterator& operator-- () {
                        // SHENANIGANS: same reasons as operator++
                        new(&data) value_type{ (data.first - 1), *(&data.second - 1) };
                        return *this;
                }
                iterator operator-- (int) { iterator tmp = *this; --(*this); return tmp; }

                bool operator== (const iterator& o) const {
                        return data.first == o.data.first && &data.second == &o.data.second;
                }
                bool operator!= (const iterator& that) const { return !(*this == that); }
        };

        class const_iterator : public std::iterator< std::bidirectional_iterator_tag,
                                                     const_value_type,
                                                                                                  difference_type,
                                                                                                  const_pointer,
                                                                                                  const_reference  > {
        friend class VectorMap;
                const_value_type data;

                const_iterator(size_type i, const std::vector<T>& v) : data(i, v[i]) {}
        public:
                const_iterator(const iterator& that) : data(that.data) {}
                const_iterator(const const_iterator& that) : data(that.data) {}
                const_iterator& operator= (const iterator& that) {
                        new(&data) const_value_type{ that.data };
                        return *this;
                }
                const_iterator& operator= (const const_iterator& that) {
                        new(&data) const_value_type{ that.data };
                        return *this;
                }

                const_reference operator* () { return data; }
                const_pointer operator-> () { return &data; }

                const_iterator& operator++ () {
                        // SHENANIGANS: same reasons as iterator::operator++
                        new(&data) const_value_type{ (data.first + 1), *(&data.second + 1) };
                        return *this;
                }
                const_iterator operator++ (int) { const_iterator tmp = *this; ++(*this); return tmp; }

                const_iterator& operator-- () {
                        // SHENANIGANS: same reasons as iterator::operator++
                        new(&data) const_value_type{ (data.first - 1), *(&data.second - 1) };
                        return *this;
                }
                const_iterator operator-- (int) { const_iterator tmp = *this; --(*this); return tmp; }

                bool operator== (const const_iterator& o) const {
                        return data.first == o.data.first && &data.second == &o.data.second;
                }
                bool operator!= (const const_iterator& that) const { return !(*this == that); }
        };

        /// Reserve space for n elements
        void reserve(size_type n) {
                if ( n > data.size() ) { data.insert( data.end(), n - data.size(), T{} ); }
        }

        /// Unsafe access; no bounds checking
        T& operator[] (size_type i) { return data[i]; }
        const T& operator[] (size_type i) const { return data[i]; }

        /// Safe access; will insert new values if needed
        T& at(size_type i) {
                reserve(i+1);
                return data[i];
        }

        /// Number of stored values
        unsigned size() const { return data.size(); }

        /// No stored values
        bool empty() const { return data.empty(); }

        /// Empties the map
        void clear() { data.clear(); }

        /// Returns 1 if element in map, 0 otherwise
        size_type count( size_type i ) const { return i < size() ? 1 : 0; }

        iterator begin() { return iterator{ 0, data }; }
        const_iterator begin() const { return const_iterator{ 0, data }; }
        const_iterator cbegin() const { return const_iterator{ 0, data }; }

        iterator end() { return iterator{ data.size(), data }; }
        const_iterator end() const { return const_iterator{ data.size(), data }; }
        const_iterator cend() const { return const_iterator{ data.size(), data }; }

        iterator find( size_type i ) { return i < size() ? iterator{ i, data } : end(); }
        const_iterator find( size_type i ) const { return i < size() ? const_iterator{ i, data } : end(); }
};

#endif // _VECTORMAP_H

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