[common] Modify index type for correspondences (#4231)

common/include/pcl/correspondence.h

@@ -42,6 +42,7 @@
 #pragma GCC system_header
 #endif
 
+#include <pcl/pcl_base.h>
 #include <pcl/memory.h>
 #include <pcl/types.h>
 #include <Eigen/StdVector>
@@ -60,9 +61,9 @@ namespace pcl
   struct Correspondence
   {
     /** \brief Index of the query (source) point. */
-    int index_query = 0;
+    index_t index_query = 0;
     /** \brief Index of the matching (target) point. Set to -1 if no correspondence found. */
-    int index_match = -1;
+    index_t index_match = UNAVAILABLE;
     /** \brief Distance between the corresponding points, or the weight denoting the confidence in correspondence estimation */
     union
     {
@@ -76,7 +77,7 @@ namespace pcl
     inline Correspondence () = default;
 
     /** \brief Constructor. */
-    inline Correspondence (int _index_query, int _index_match, float _distance) :
+    inline Correspondence (index_t _index_query, index_t _index_match, float _distance) :
       index_query (_index_query), index_match (_index_match), distance (_distance)
     {}