From dcd6f6d60df3bbf9ff2ecae3914b627395139cd6 Mon Sep 17 00:00:00 2001
From: Joachim Schoeberl <joachim.schoeberl@tuwien.ac.at>
Date: Wed, 8 Jan 2025 08:25:12 +0100
Subject: [PATCH] TablePrefixSum 32/64 bit decision

---
 libsrc/core/table.cpp       |  4 ++--
 libsrc/core/table.hpp       | 14 ++++++++++++++
 libsrc/meshing/meshtype.hpp |  9 ++++++++-
 3 files changed, 24 insertions(+), 3 deletions(-)

diff --git a/libsrc/core/table.cpp b/libsrc/core/table.cpp
index 1fbcda75..b71cb615 100644
--- a/libsrc/core/table.cpp
+++ b/libsrc/core/table.cpp
@@ -62,9 +62,9 @@ namespace ngcore
     return index;
   }
 
-  NGCORE_API size_t * TablePrefixSum32 (FlatArray<unsigned int> entrysize)
+  NGCORE_API size_t * TablePrefixSum32 (FlatArray<uint32_t> entrysize)
   { return TablePrefixSum2 (entrysize); }
-  NGCORE_API size_t * TablePrefixSum64 (FlatArray<size_t> entrysize)
+  NGCORE_API size_t * TablePrefixSum64 (FlatArray<uint64_t> entrysize)
   { return TablePrefixSum2 (entrysize); }
 
   /*
diff --git a/libsrc/core/table.hpp b/libsrc/core/table.hpp
index d2326c26..f7ba47ea 100644
--- a/libsrc/core/table.hpp
+++ b/libsrc/core/table.hpp
@@ -94,6 +94,7 @@ namespace ngcore
     Iterator end() const { return Iterator(*this, BASE+size); }
   };
 
+  /*
   NGCORE_API extern size_t * TablePrefixSum32 (FlatArray<unsigned int> entrysize);
   NGCORE_API extern size_t * TablePrefixSum64 (FlatArray<size_t> entrysize);
 
@@ -106,7 +107,20 @@ namespace ngcore
   { return TablePrefixSum32 (FlatArray<unsigned> (entrysize.Size(), (unsigned int*)(std::atomic<int>*)entrysize.Addr(0))); }
   NETGEN_INLINE size_t * TablePrefixSum (FlatArray<size_t> entrysize)
   { return TablePrefixSum64 (entrysize); }
+  */
 
+  NGCORE_API extern size_t * TablePrefixSum32 (FlatArray<uint32_t> entrysize);
+  NGCORE_API extern size_t * TablePrefixSum64 (FlatArray<uint64_t> entrysize);
+
+  template <typename T> // TODO: enable_if T is integral
+  NETGEN_INLINE size_t * TablePrefixSum (FlatArray<T> entrysize)
+  {
+    if constexpr (sizeof(T) == 4)
+      return TablePrefixSum32 ( { entrysize.Size(), (uint32_t*)(void*)entrysize.Addr(0) });
+    else
+      return TablePrefixSum64 ( { entrysize.Size(), (uint64_t*)(void*)entrysize.Addr(0) });
+  }
+  
 
   /**
      A compact Table container.
diff --git a/libsrc/meshing/meshtype.hpp b/libsrc/meshing/meshtype.hpp
index 619b3e41..27597581 100644
--- a/libsrc/meshing/meshtype.hpp
+++ b/libsrc/meshing/meshtype.hpp
@@ -138,6 +138,8 @@ namespace netgen
 
     class t_invalid { public: constexpr t_invalid() = default; };
     static constexpr t_invalid INVALID{};
+
+    typedef decltype( declval<T>()-declval<T>() ) T_diff;
     
   public:
     constexpr Index () = default;
@@ -182,11 +184,16 @@ namespace netgen
     TIndex operator-- (int) { TIndex hi(*this); i--; return hi; }
     TIndex & operator++ () { i++; return static_cast<TIndex&>(*this); }
     TIndex & operator-- () { i--; return static_cast<TIndex&>(*this); }
+
+    /*
     constexpr TIndex operator+= (int add) { i += add; return TIndex{*this}; }
     constexpr TIndex operator+= (size_t add) { i += add; return TIndex{*this}; }
     constexpr TIndex operator-= (int add) { i -= add; return TIndex{*this}; }
     constexpr TIndex operator-= (size_t add) { i -= add; return TIndex{*this}; }
-
+    */
+    constexpr TIndex operator+= (T_diff add) { i += add; return TIndex{*this}; }
+    constexpr TIndex operator-= (T_diff add) { i -= add; return TIndex{*this}; }
+    
     constexpr auto operator- (Index i2) const { return i-i2.i; }
 
     // bool operator== (Index i2) const { return i==i2.i; }