From fb94a382bbe20754502fb31a3fe8dbde4b12c77c Mon Sep 17 00:00:00 2001
From: Christian Zimmermann <christian.zimmermann@ur.de>
Date: Tue, 8 Nov 2022 22:36:16 +0100
Subject: [PATCH] base/isq.h + base/iter.* + functional/fundamental.h +
 adaptions in mrange (WIP)

---
 src/include/base/base.cc.h           |   1 +
 src/include/base/base.h              |   2 +
 src/include/base/isq.h               |  30 +++++
 src/include/base/iter.cc.h           |  28 +++++
 src/include/base/iter.h              |  17 +++
 src/include/base/types.h             |  11 ++
 src/include/functional/fundamental.h |  15 +++
 src/include/ranges/mrange.cc.h       | 163 +++++++--------------------
 src/include/ranges/mrange.h          |  56 ++-------
 9 files changed, 151 insertions(+), 172 deletions(-)
 create mode 100644 src/include/base/isq.h
 create mode 100644 src/include/base/iter.cc.h
 create mode 100644 src/include/base/iter.h
 create mode 100644 src/include/functional/fundamental.h

diff --git a/src/include/base/base.cc.h b/src/include/base/base.cc.h
index cd0374a..995301f 100644
--- a/src/include/base/base.cc.h
+++ b/src/include/base/base.cc.h
@@ -2,3 +2,4 @@
 #include "dtype.cc.h"
 #include "obj_handle.cc.h"
 #include "to_string.cc.h"
+#include "iter.cc.h"
diff --git a/src/include/base/base.h b/src/include/base/base.h
index 5897c99..c75373f 100644
--- a/src/include/base/base.h
+++ b/src/include/base/base.h
@@ -22,6 +22,8 @@
 #include "types.h"
 #include "obj_handle.h"
 #include "dtype.h"
+#include "isq.h"
+#include "iter.h"
 
 #include "base.cc.h"
 
diff --git a/src/include/base/isq.h b/src/include/base/isq.h
new file mode 100644
index 0000000..b4d77c3
--- /dev/null
+++ b/src/include/base/isq.h
@@ -0,0 +1,30 @@
+
+#ifndef __cxz_isq_h__
+#define __cxz_isq_h__
+
+#include <cstdlib>
+#include <utility>
+#include "types.h"
+
+namespace CNORXZ
+{
+    template <SizeT O, SizeT... Is>
+    std::index_sequence<(Is+O)...> mkIsqAdd(std::index_sequence<is...> is) { return {}; }
+
+    template <SizeT B, SizeT E>
+    struct MkIsq
+    {
+	static auto make()
+	{
+	    static_assert(B <= E, "begin of sequence must be smaller than end of sequence");
+	    return mkIsqAdd<B>( std::make_index_sequence<E-B> );
+	}
+
+	typedef decltype(make()) type;
+    };
+    
+    template <SizeT B, SizeT E>
+    using Isqr = MkIsq<B,E>::type;
+}
+
+#endif
diff --git a/src/include/base/iter.cc.h b/src/include/base/iter.cc.h
new file mode 100644
index 0000000..8289dad
--- /dev/null
+++ b/src/include/base/iter.cc.h
@@ -0,0 +1,28 @@
+
+#ifndef __cxz_iter_cc_h__
+#define __cxz_iter_cc_h__
+
+#include "iter.h"
+#include "functional/fundamental.h"
+
+namespace CNORXZ
+{
+    template <class G, class F, SizeT... Is>
+    constexpr decltype(auto) iteri(const G& g, const F& f, Isq<Is...> is)
+    {
+	if constexpr(std::is_same<F,NoF>::value){
+	    ( g(std::integral_constant<SizeT,Is>{}, args...), ... );
+	}
+	else {
+	    return f( g(std::integral_constant<SizeT,Is>{}, args...) ... );
+	}
+    }
+
+    template <SizeT B, SizeT E, class G, class F>
+    constexpr decltype(auto) iter(const G& g, const F& f)
+    {
+	return iteri(g, f, Isqr<B,E>{});
+    }
+}
+
+#endif
diff --git a/src/include/base/iter.h b/src/include/base/iter.h
new file mode 100644
index 0000000..abc088e
--- /dev/null
+++ b/src/include/base/iter.h
@@ -0,0 +1,17 @@
+
+#ifndef __cxz_iter_h__
+#define __cxz_iter_h__
+
+#include <cstdlib>
+#include "types.h"
+
+namespace CNORXZ
+{
+    template <class G, class F, SizeT... Is>
+    constexpr decltype(auto) iteri(const G& g, const F& f, Isq<Is...> is);
+
+    template <SizeT B, SizeT E, class G, class F>
+    constexpr decltype(auto) iter(const G& g, const F& f);
+}
+
+#endif
diff --git a/src/include/base/types.h b/src/include/base/types.h
index dba8140..07c288f 100644
--- a/src/include/base/types.h
+++ b/src/include/base/types.h
@@ -10,6 +10,7 @@
 #include <array>
 #include <map>
 #include <typeinfo>
+#include <utility>
 
 namespace CNORXZ
 {
@@ -43,10 +44,20 @@ namespace CNORXZ
     template <SizeT I, typename... T>
     using TupleElem = std::tuple_element<I,Tuple<T...>>;
 
+    template <typename T>
+    using RemoveRef = std::remove_reference<T>::type;
+    
     template <typename K, typename V>
     using Map = std::map<K,V>;
 
     typedef std::type_info TypeInfo;
+
+    template <SizeT... Is>
+    using Isq = std::index_sequence<Is...>;
+    // cxz helper functions/classes: -> isq.h
+
+    template <class... T>
+    using Isqf = std::index_sequence_for<T...>;
     
     /*********************
      *   library types   *
diff --git a/src/include/functional/fundamental.h b/src/include/functional/fundamental.h
new file mode 100644
index 0000000..9a7d707
--- /dev/null
+++ b/src/include/functional/fundamental.h
@@ -0,0 +1,15 @@
+
+#ifndef __cxz_fundamental_h__
+#define __cxz_fundamental_h__
+
+#include <cstdlib>
+
+namespace CNORXZ
+{
+    struct NoF
+    {
+	constexpr void operator()() const {};
+    };
+}
+
+#endif
diff --git a/src/include/ranges/mrange.cc.h b/src/include/ranges/mrange.cc.h
index 7648e7c..ce7a328 100644
--- a/src/include/ranges/mrange.cc.h
+++ b/src/include/ranges/mrange.cc.h
@@ -12,85 +12,25 @@ namespace CNORXZ
      *   MIndex (private)  *
      ***********************/
 
-    template <class... Indices>
-    template <SizeT P, SizeT... Is>
-    constexpr decltype(auto) MIndex<Indices...>::indexSequencePlus(std::index_sequence<Is...> is) const
-    {
-	return std::index_sequence<P+Is...> {};
-    }
-
-    template <class... Indices>
-    template <SizeT B, SizeT E>
-    constexpr decltype(auto) MIndex<Indices...>::mkIndexSequence() const
-    {
-	return indexSequencePlus<B>(std::make_index_sequence<E-B>{});
-    }
-
-    template <class... Indices>
-    template <class G, class F, SizeT... Is>
-    constexpr decltype(auto) MIndex<Indices...>::accumulatei(const G& g, const F& f, std::index_sequence<Is...> is) const
-    {
-	return f( g(std::get<Is>(mIPack))... );
-    }
-    
-    template <class... Indices>
-    template <class G, class F, SizeT... Is>
-    constexpr decltype(auto) MIndex<Indices...>::accumulate2i(const G& g, const F& f, std::index_sequence<Is...> is) const
-    {
-	return f( g(std::get<Is>(mIPack), std::get<Is>(mBlockSizes))... );
-    }
-
-    template <class... Indices>
-    template <SizeT B, SizeT E, class G, class F>
-    constexpr decltype(auto) MIndex<Indices...>::accumulate(const G& g, const F& f) const
-    {
-	return accumulatei(g, f, mkIndexSequence<B,E>())
-    }
-
-    template <class... Indices>
-    template <SizeT B, SizeT E, class G, class F>
-    constexpr decltype(auto) MIndex<Indices...>::accumulate2(const G& g, const F& f) const
-    {
-	return accumulate2i(g, f, mkIndexSequence<B,E>())
-    }
-
     template <class... Indices>
     template <SizeT... Is>
-    constexpr decltype(auto) MIndex<Indices...>::mkIPack(SizeT pos, std::index_sequence<Is...> is) const
+    constexpr decltype(auto) MIndex<Indices...>::mkIPack(SizeT pos, Isq<Is...> is) const
     {
-	static_assert(sizeof...(Is) == sizeof...(Indices),
+	static_assert(sizeof...(Is) == NI,
 		      "sequence size does not match number of indices");
 	return std::make_tuple( std::make_shared<Indices>( mRange->sub(Is) )... );
-				//, (pos / std::get<Is>(mBlockSizes) ) %  )... );
     }
     
     template <class... Indices>
-    template <SizeT... Is>
-    inline void MIndex<Indices...>::setIPack(std::index_sequence<Is...> is) const
+    constexpr decltype(auto) MIndex<Indices...>::mkBlockSizes() const
     {
-	( (std::get<Is>(mIPack) = (IB::mPos / std::get<Is>(mBlockSize)) % std::get<Is>(mIPack)->max() ),... );
-    }
-    
-    template <class... Indices>
-    template <SizeT... Is>
-    constexpr decltype(auto) MIndex<Indices...>::mkBlockSizes(std::index_sequence<Is...> is) const
-    {
-	static_assert(sizeof...(Is) == sizeof...(Indices)-1,
-		      "set lowest block size manually");
 	return std::make_tuple
-	    ( accumulate<Is,sizeof...(Indices)>
-	      ( [](const auto& i) { return i->max(); },
-		[](const auto&... as) { return (as * ...); } )...,
+	    ( iter<Is,NI>
+	      ( [&](auto i) { return std::get<i>(mIPack)->max(); },
+		[&](const auto&... as) { return (as * ...); } )...,
 	      SPos<1>() );
     }
 
-    template <class... Indices>
-    template <SizeT... Is>
-    constexpr decltype(auto) MIndex<Indices...>::mkPos(std::index_sequence<Is...> is) const
-    {
-	return ( (std::get<Is>(mIPack)*std::get<Is>(mBlockSizes)) + ... );
-    }
-
     template <class... Indices>
     template <SizeT I>
     inline void MIndex<Indices...>::up()
@@ -125,33 +65,6 @@ namespace CNORXZ
 	--(*i);
     }
 
-    template <class... Indices>
-    template <SizeT... Is>
-    inline String MIndex<Indices...>::mkStringMeta(std::index_sequence<Is...> is) const
-    {
-	const String blim = "[";
-	const String elim = "]";
-	const String dlim = ",";
-	static_assert(sizeof...(Is) == sizeof...(Indices)-1,
-		      "set last position outside the index pack");
-	if constexpr(sizeof...(Is) == 0){
-	    return blim + std::get<0>(mIPack)->stringMeta() + elim;
-	}
-	else {
-	    return blim +
-		( ( std::get<Is>(mIPack)->stringMeta() + dlim ) + ... +
-		  std::get<sizeof...(Indices)-1>(mIPack)->stringMeta() )
-		+ elim;
-	}
-    }
-
-    template <class... Indices>
-    template <SizeT... Is>
-    inline typename MIndex<Indices...>::MetaType MIndex<Indices...>::mkMeta(std::index_sequence<Is...> is) const
-    {
-	return std::make_tuple( std::get<Is>(mIPack)->meta()... );
-    }
-    
     template <class... Indices>
     template <SizeT I, class Xpr, class F>
     constexpr decltype(auto) MIndex<Indices...>::mkIFor(const Xpr& xpr, F&& f) const
@@ -164,12 +77,6 @@ namespace CNORXZ
 	}
     }
 
-    template <SizeT... Is>
-    inline void ati(const MetaType& meta, std::index_sequence<Is...> is) const
-    {
-	( std::get<Is>(mIPack)->at( std::get<Is>(meta) ), ... );
-    }
-
     /**************
      *   MIndex   *
      **************/
@@ -178,8 +85,8 @@ namespace CNORXZ
     template <class MRange>
     MIndex<Indices...>::MIndex(const Sptr<MRange>& range, SizeT pos) :
 	IndexInterface<MIndex<Indices...>,Tuple<typename Indices::MetaType...>>(0),
-	mIPack(mkIPack(IB::mPos, std::make_index_sequence<sizeof...(Indices)>{})),
-	mBlockSizes(mkBlockSizes(IB::mPos), std::make_index_sequence<sizeof...(Indices)>{}),
+	mIPack(mkIPack(IB::mPos, Isqr<0,NI>{})),
+	mBlockSizes(mkBlockSizes(IB::mPos), Isqr<0,NI>{}),
 	mRange(range),
     {
 	(*this) = pos;
@@ -189,7 +96,9 @@ namespace CNORXZ
     MIndex<Indices...>& MIndex<Indices...>::operator()(const Sptr<MIndex>& mi)
     {
 	mIPack = mi.mIPack;
-	IB::mPos = mkPos(std::make_index_sequence<sizeof...(Indices)>{});
+	IB::mPos = iter<0,NI>
+	    ( [&](auto i) { return std::get<i>(mIPack)*std::get<i>(mBlockSizes); },
+	      [](const auto&... xs) { return (xs + ...); });
 	return *this;
     }
 
@@ -197,7 +106,7 @@ namespace CNORXZ
     MIndex<Indices...>& MIndex<Indices...>::operator=(SizeT pos)
     {
 	IB::mPos = pos;
-	setIPack(std::make_index_sequence<sizeof...(Indices)>{});
+	iter<0,NI>( [&](auto i) { std::get<i>(mIPack) = (IB::mPos / std::get<i>(mBlockSize)) % std::get<i>(mIPack)->max() }, NoF{} );
 	return *this;
     }
 
@@ -207,7 +116,7 @@ namespace CNORXZ
 	// End state is defined by high-index being end while all other indices are zero
 	auto& i0 = std::get<0>(mIPack);
 	if(i0->pos() != i0->max()){
-	    up<sizeof...(Indices)-1>();
+	    up<NI-1>();
 	}
 	return *this;
     }
@@ -216,7 +125,7 @@ namespace CNORXZ
     MIndex<Indices...>& MIndex<Indices...>::operator--()
     {
 	if(IB::mPos != 0){
-	    down<sizeof...(Indices)-1>();
+	    down<NI-1>();
 	}
 	return *this;
     }
@@ -224,27 +133,37 @@ namespace CNORXZ
     template <class... Indices>
     String MIndex<Indices...>::stringMeta() const
     {
-	return mkStringMeta(std::make_index_sequence<sizeof...(Indices)-1>{});
+	const String blim = "[";
+	const String elim = "]";
+	const String dlim = ",";
+	return iter<1,NI>
+	    ( [&](auto i) { return std::get<i>(mIPack)->stringMeta(); },
+	      [&](const auto&... xs) {
+		  return blim + std::get<0>(mIPack)->stringMeta() + ( (dlim + xs) + ... ) + elim;
+	      } );
     }
     
     template <class... Indices>
     typename MIndex<Indices...>::MetaType MIndex<Indices...>::meta() const
     {
-	return mkMeta(std::make_index_sequence<sizeof...(Indices)>{});
+	return iter<0,NI>( [&](auto i) { return std::get<i>(mIPack)->meta(); },
+			   [](const auto&... xs) { return std::make_tuple(xs...); } );
     }
 
     template <class... Indices>
     MIndex<Indices...>& MIndex<Indices...>::at(const MetaType& metaPos)
     {
-	ati(metaPos, std::make_index_sequence<sizeof...(Indices)>{});
-	IB::mPos = mkPos(std::make_index_sequence<sizeof...(Indices)>{});
+	iter<0,NI>( [&](auto i) { std::get<Is>(mIPack)->at( std::get<Is>(meta) ) }, NoF {} );
+	IB::mPos = iter<0,NI>
+	    ( [&](auto i) { return std::get<i>(mIPack)*std::get<i>(mBlockSizes); },
+	      [](const auto&... xs) { return (xs + ...); });
 	return *this;
     }
 
     template <class... Indices>
     SizeT MIndex<Indices...>::dim()
     {
-	return sizeof...(Indices);
+	return NI;
     }
 
     template <class... Indices>
@@ -258,8 +177,9 @@ namespace CNORXZ
     template <SizeT I>
     decltype(auto) MIndex<Indices...>::stepSize(const IndexId<I>& id) const;
     {
-	return accumulate2( [](const auto& i, const auto& b) { return i->stepSize(id) * b },
-			    [](const auto&... ss) { return ( ss + ... ); });
+	return iter<0,NI>
+	    ( [&](auto i) { return std::get<i>(mIPack)->stepSize(id) * std::get<i>(mBlockSize); },
+	      [](const auto&... ss) { return ( ss + ... ); });
     }
 
     template <class... Indices>	
@@ -307,7 +227,7 @@ namespace CNORXZ
     template <class... Ranges>
     MRange<Ranges...>::MRange(const Tuple<Sptr<Ranges>...>& rs) :
 	mRs(rs),
-	mA( mkA( std::make_index_sequence<sizeof...(Ranges)>{} ) )
+	mA( mkA( std::make_index_sequence<NR>{} ) )
     {}
 
     template <class... Ranges>
@@ -320,13 +240,14 @@ namespace CNORXZ
     template <class... Ranges>
     SizeT MRange<Ranges...>::size() const
     {
-	return this->sizei(std::make_index_sequence<sizeof...(Ranges)> {});
+	return iter<0,NR>( [&](auto i) { return std::get<i>(mRs)->size() },
+			   [](const auto&... xs) { return (xs * ...); } );
     }
 
     template <class... Ranges>
     SizeT MRange<Ranges...>::dim() const
     {
-	return sizeof...(Ranges);
+	return NR;
     }
     
     template <class... Ranges>
@@ -359,16 +280,10 @@ namespace CNORXZ
      ************************/
 
     template <class... Ranges>
-    template <SizeT... Is>
-    decltype(auto) MRange<Ranges...>::mkA(std::index_sequence<Is...> is) const
+    decltype(auto) MRange<Ranges...>::mkA() const
     {
-	return Arr<RangePtr,sizeof...(Ranges)> { std::get<Is>(mRs)... };
-    }
-
-    template <class... Ranges>
-    SizeT MRange<Ranges...>::sizei(std::index_sequence<Is...> is) const
-    {
-	return ( std::get<Is>(mRs)->size() * ... );
+	return iter<0,NR>([&](auto i) { return std::get<Is>(mRs); },
+			  [](const auto&... xs) { return Arr<RangePtr,NR> { xs... } } );
     }
     
 }
diff --git a/src/include/ranges/mrange.h b/src/include/ranges/mrange.h
index 074a074..0b584f0 100644
--- a/src/include/ranges/mrange.h
+++ b/src/include/ranges/mrange.h
@@ -22,6 +22,7 @@ namespace CNORXZ
 	typedef Tuple<Sptr<Indices>...> IndexPack;
 	typedef Tuple<typename Indices::MetaType...> MetaType;
 	typedef MRange<typename Indices::RangeType...> RangeType;
+	static constexpr SizeT NI = sizeof...(Indices);
 
 	// NO DEFAULT HERE !!!
 	// ( have to assign sub-indices (ptr!) correctly )
@@ -69,43 +70,14 @@ namespace CNORXZ
 	MIndex() = default;
 	
 	IndexPack mIPack;
-	//Arr<SizeT,sizeof...(Indices)> mBlockSizes;
-	typedef decltype(mkBlockSizes(std::make_index_sequence<sizeof...(Indices)-1>{})) BlockTuple;
+	typedef decltype(mkBlockSizes(Isqr<0,NI-1>{})) BlockTuple;
 	BlockTuple mBlockSizes;
 	Sptr<RangeType> mRange;
 
-	// shift to utils:
-	template <SizeT P, SizeT... Is>
-	constexpr decltype(auto) indexSequencePlus(std::index_sequence<Is...> is) const;
-
-	// shift to utils:
-	template <SizeT B, SizeT E>
-	constexpr decltype(auto) mkIndexSequence() const;
-
-	
-	template <class G, class F, SizeT... Is>
-	constexpr decltype(auto) accumulatei(const G& g, const F& f, std::index_sequence<Is...> is) const;
-
-	template <class G, class F, SizeT... Is>
-	constexpr decltype(auto) accumulate2i(const G& g, const F& f, std::index_sequence<Is...> is) const;
-
-	template <SizeT B, SizeT E, class G, class F>
-	constexpr decltype(auto) accumulate(const G& g, const F& f) const;
-
-	template <SizeT B, SizeT E, class G, class F>
-	constexpr decltype(auto) accumulate2(const G& g, const F& f) const;
-
 	template <SizeT... Is>
-	constexpr decltype(auto) mkIPack(SizeT pos, std::index_sequence<Is...> is) const;
+	constexpr decltype(auto) mkIPack(SizeT pos, Isq<Is...> is) const;
 
-	template <SizeT... Is>
-	inline void setIPack(std::index_sequence<Is...> is) const;
-
-	template <SizeT... Is>
-	constexpr decltype(auto) mkBlockSizes(std::index_sequence<Is...> is) const;
-
-	template <SizeT... Is>
-	constexpr decltype(auto) mkPos(std::index_sequence<Is...> is) const;
+	constexpr decltype(auto) mkBlockSizes() const;
 
 	template <SizeT I>
 	inline void up();
@@ -113,17 +85,8 @@ namespace CNORXZ
 	template <SizeT I>
 	inline void down();
 
-	template <SizeT... Is>
-	inline String mkStringMeta(std::index_sequence<Is...> is) const;
-
-	template <SizeT... Is>
-	inline MetaType mkMeta(std::index_sequence<Is...> is) const;
-
 	template <SizeT I, class Xpr, class F>
 	constexpr decltype(auto) mkIFor(const Xpr& xpr, F&& f) const;
-
-	template <SizeT... Is>
-	inline void ati(const MetaType& meta, std::index_sequence<Is...> is) const;
     };
 
     // modified blockSizes; to be used for Slices; can be created from MIndices
@@ -142,7 +105,7 @@ namespace CNORXZ
 	BlockType mBlockSizes;
 
 	template <SizeT... Is>
-	constexpr decltype(auto) mkPos(std::index_sequence<Is...> is) const;
+	constexpr decltype(auto) mkPos(Isq<Is...> is) const;
     };
 
     // NOT THREAD SAVE
@@ -169,6 +132,7 @@ namespace CNORXZ
 	typedef RangeBase RB;
 	typedef MIndex<typename Ranges::IndexType...> IndexType;
         typedef Tuple<typename Ranges::IndexType::MetaType...> MetaType;
+	static constexpr SizeT NR = sizeof...(Ranges);
 
 	friend MRangeFactory<Ranges...>;
 
@@ -190,14 +154,10 @@ namespace CNORXZ
 	MRange(const Tuple<Sptr<Ranges>...>& rs);
 	
 	Tuple<Sptr<Ranges>...> mRs;
-	Arr<RangePtr,sizeof...(Ranges)> mA;
+	Arr<RangePtr,NR> mA;
     private:
 
-	template <SizeT... Is>
-	decltype(auto) mkA(std::index_sequence<Is...> is) const;
-
-	template <SizeT... Is>
-	SizeT sizei(std::index_sequence<Is...> is) const;
+	decltype(auto) mkA() const;
     };
     
 }