add a wrapper for the distance table for better access

util/dist_table_wrapper.hpp

@@ -0,0 +1,95 @@
+/*
+
+Copyright (c) 2015, Project OSRM contributors
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without modification,
+are permitted provided that the following conditions are met:
+
+Redistributions of source code must retain the above copyright notice, this list
+of conditions and the following disclaimer.
+Redistributions in binary form must reproduce the above copyright notice, this
+list of conditions and the following disclaimer in the documentation and/or
+other materials provided with the distribution.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
+ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
+ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+*/
+
+#ifndef DIST_TABLE_WRAPPER_H
+#define DIST_TABLE_WRAPPER_H
+
+#include <vector>
+#include <utility>
+#include <boost/assert.hpp>
+
+//This Wrapper provides an easier access to a distance table that is given as an linear vector
+
+template <typename T> class DistTableWrapper {
+public:
+
+    using Iterator = typename std::vector<T>::iterator;
+    using ConstIterator = typename std::vector<T>::const_iterator;
+
+    DistTableWrapper(std::vector<T> table, std::size_t number_of_nodes)
+                     : table_(std::move(table)), number_of_nodes_(number_of_nodes) {
+        BOOST_ASSERT_MSG(table.size() == 0, "table is empty");
+        BOOST_ASSERT_MSG(number_of_nodes_ * number_of_nodes_ < table_, "number_of_nodes_ is invalid");
+    };
+
+    std::size_t GetNumberOfNodes() const {
+        return number_of_nodes_;
+    }
+
+    std::size_t size() const {
+        return table_.size();
+    }
+
+    EdgeWeight operator() (NodeID from, NodeID to) const {
+        BOOST_ASSERT_MSG(from < number_of_nodes_, "from ID is out of bound");
+        BOOST_ASSERT_MSG(to < number_of_nodes_, "to ID is out of bound");
+        const auto index = from * number_of_nodes_ + to;
+        BOOST_ASSERT_MSG(index < table_size(), "index is out of bound");
+        return  table_[index];
+    }
+
+    ConstIterator begin() const{
+        return std::begin(table_);
+    }
+
+    Iterator begin() {
+        return std::begin(table_);
+    }
+
+    ConstIterator end() const{
+        return std::end(table_);
+    }
+
+    Iterator end() {
+        return std::end(table_);
+    }
+
+    NodeID GetIndexOfMaxValue() const {
+        return std::distance(table_.begin(), std::max_element(table_.begin(), table_.end()));
+    }
+
+    std::vector<T> GetTable() const {
+        return table_;
+    }
+
+private:
+    std::vector<T> table_;
+    const std::size_t number_of_nodes_;
+};
+
+
+#endif // DIST_TABLE_WRAPPER_H