From ee3e1b5d4f036c17af970a7884b9f70eb63d72b5 Mon Sep 17 00:00:00 2001
From: Christian Zimmermann <christian.zimmermann@ur.de>
Date: Sun, 27 Oct 2024 00:47:53 -0700
Subject: [PATCH] various improvements regarding static pos evaluation

---
 src/include/ranges/lindex.cc.h |  8 +++++++-
 src/include/ranges/srange.h    | 16 ++++++++++++++++
 src/include/xpr/pos_type.cc.h  | 10 ++++++++--
 src/include/xpr/pos_type.h     |  1 +
 4 files changed, 32 insertions(+), 3 deletions(-)

diff --git a/src/include/ranges/lindex.cc.h b/src/include/ranges/lindex.cc.h
index 5ec5342..173ed19 100644
--- a/src/include/ranges/lindex.cc.h
+++ b/src/include/ranges/lindex.cc.h
@@ -49,7 +49,13 @@ namespace CNORXZ
     template <class Xpr, class F>
     decltype(auto) LIndex<Index,L>::ifor(const Xpr& xpr, F&& f) const
     {
-	return For<L,Xpr,F>(this->pmax().val(), this->id(), xpr, std::forward<F>(f));
+	if constexpr(index_has_const_size<Index>::value){
+	    constexpr SizeT S = index_const_size<Index>::value;
+	    return SFor<S,L,Xpr,F>(this->id(), xpr, std::forward<F>(f));
+	}
+	else {
+	    return For<L,Xpr,F>(this->pmax().val(), this->id(), xpr, std::forward<F>(f));
+	}
     }
     
     template <class Index, SizeT L, class I1>
diff --git a/src/include/ranges/srange.h b/src/include/ranges/srange.h
index dc7598f..d03f502 100644
--- a/src/include/ranges/srange.h
+++ b/src/include/ranges/srange.h
@@ -247,6 +247,22 @@ namespace CNORXZ
     {
 	static constexpr bool value = true;
     };
+
+    /** ***
+	SIndex has static range size
+	@see index_expression_exists
+     */    
+    template <typename MetaT, SizeT S>
+    struct index_has_const_size<SIndex<MetaT,S>>
+    { static constexpr bool value = true; };
+
+    /** ***
+	SIndex has static range size
+	@see index_expression_exists
+     */    
+    template <typename MetaT, SizeT S>
+    struct index_const_size<SIndex<MetaT,S>>
+    { static constexpr SizeT value = S; };
 }
 
 #endif
diff --git a/src/include/xpr/pos_type.cc.h b/src/include/xpr/pos_type.cc.h
index 2837adb..32b3fc3 100644
--- a/src/include/xpr/pos_type.cc.h
+++ b/src/include/xpr/pos_type.cc.h
@@ -480,13 +480,19 @@ namespace CNORXZ
 	return mNext;
     }
 
+    template <class BPosT, class NPosT>
+    constexpr const BPosT& MPos<BPosT,NPosT>::bpos() const
+    {
+	return *this;
+    }
+
     template <class BPosT, class NPosT>
     template <class PosT>
     constexpr decltype(auto) MPos<BPosT,NPosT>::operator+(const PosT& a) const
     {
-	typedef decltype(BPosT::operator+(a)) OBPosT;
+	typedef decltype(BPosT::operator+(a.bpos())) OBPosT;
 	typedef decltype(mNext + a.next()) ONPosT;
-	return MPos<OBPosT,ONPosT>( BPosT::operator+(a), mNext + a.next() );
+	return MPos<OBPosT,ONPosT>( BPosT::operator+(a.bpos()), mNext + a.next() );
     }
 
     template <class BPosT, class NPosT>
diff --git a/src/include/xpr/pos_type.h b/src/include/xpr/pos_type.h
index 14505d1..99597ef 100644
--- a/src/include/xpr/pos_type.h
+++ b/src/include/xpr/pos_type.h
@@ -177,6 +177,7 @@ namespace CNORXZ
 
 	constexpr SizeT size() const;
 	constexpr const NPosT& next() const;
+	constexpr const BPosT& bpos() const;
 
 	template <class PosT>
 	constexpr decltype(auto) operator+(const PosT& a) const;