Pure SoA: NextID as Long

This is a leftover from an earlier implementation of pure SoA.
Our 39bit particle ids must be stored in an `amrex::Long`. An `int`
will crop them to 32bit range, which we quickly run out from.

Src/Particle/AMReX_ParticleTile.H

@@ -423,19 +423,19 @@ struct SoAParticle : SoAParticleBase
         return this->m_particle_tile_data.m_rdata[position_index][m_index];
     }
 
-    static int NextID ();
+    static Long NextID ();
 
     /**
     * \brief This version can only be used inside omp critical.
     */
-    static int UnprotectedNextID ();
+    static Long UnprotectedNextID ();
 
     /**
     * \brief Reset on restart.
     *
     * \param nextid
     */
-    static void NextID (int nextid);
+    static void NextID (Long nextid);
 
 private :
 
@@ -449,7 +449,7 @@ private :
 template <int NArrayReal, int NArrayInt> int SoAParticle<NArrayReal, NArrayInt>::the_next_id = 1;
 
 template <int NArrayReal, int NArrayInt>
-int
+Long
 SoAParticle<NArrayReal, NArrayInt>::NextID ()
 {
     Long next;
@@ -466,11 +466,11 @@ SoAParticle<NArrayReal, NArrayInt>::NextID ()
         amrex::Abort("SoAParticle<NArrayReal, NArrayInt>::NextID() -- too many particles");
     }
 
-    return int(next);
+    return next;
 }
 
 template <int NArrayReal, int NArrayInt>
-int
+Long
 SoAParticle<NArrayReal, NArrayInt>::UnprotectedNextID ()
 {
     int next = the_next_id++;
@@ -482,7 +482,7 @@ SoAParticle<NArrayReal, NArrayInt>::UnprotectedNextID ()
 
 template <int NArrayReal, int NArrayInt>
 void
-SoAParticle<NArrayReal, NArrayInt>::NextID (int nextid)
+SoAParticle<NArrayReal, NArrayInt>::NextID (Long nextid)
 {
     the_next_id = nextid;
 }