From 6c921e148428160d89855668e6a8acf9bf20b718 Mon Sep 17 00:00:00 2001
From: Owen Green <gungwho@gmail.com>
Date: Mon, 14 Feb 2022 14:50:09 +0000
Subject: [PATCH] `SliceIterator::end()` fix (#97)

* fix problem with 0-size slices and end() sentinels

* adds basic test for slice ietrator fix
---
 include/data/FluidTensor_Support.hpp  |  9 ++++-----
 tests/data/TestFluidTensorSupport.cpp | 26 ++++++++++++++++++++++++++
 2 files changed, 30 insertions(+), 5 deletions(-)

diff --git a/include/data/FluidTensor_Support.hpp b/include/data/FluidTensor_Support.hpp
index 331f5de1b..d611d6b81 100644
--- a/include/data/FluidTensor_Support.hpp
+++ b/include/data/FluidTensor_Support.hpp
@@ -166,11 +166,10 @@ struct SliceIterator
     
     mIndexes[0] = s.extents[0];
     
-    // size = s.size;
-    if (!s.transposed) // Not transposed
-      endoffset = s.strides[0] * s.extents[0];
-    else // transposed
-      endoffset = s.strides[N - 1] * s.extents[N - 1];
+    if (!s.transposed) 
+      endoffset = s.strides[0] * s.size ; 
+    else 
+      endoffset = s.strides[N - 1] * s.size; 
     mPtr = end ? base + s.start + endoffset : base + s.start;
   }
   
diff --git a/tests/data/TestFluidTensorSupport.cpp b/tests/data/TestFluidTensorSupport.cpp
index 4059b8a78..e6ef3aae2 100644
--- a/tests/data/TestFluidTensorSupport.cpp
+++ b/tests/data/TestFluidTensorSupport.cpp
@@ -184,3 +184,29 @@ TEST_CASE("SliceIterator does strided iteration","[FluidTensorSupport]"){
         REQUIRE(std::equal(colIterator,end,colData.begin())); 
     }
 }
+
+
+
+TEST_CASE("SliceIterator end() does sensible things","[FluidTensorSupport]"){
+  
+  std::array<int,10>  data{0,1,2,3,4,5,6,7,8,9}; 
+  fluid::FluidTensorView<int,2> view{data.data(),0,1,10};
+  auto size = GENERATE(0,1,2,3,4,5,6,7,8,9); 
+  
+  using Iterator = fluid::impl::SliceIterator<int,1>; 
+  FluidTensorSlice<1> s(size);
+  
+  auto colIterator = Iterator(s,data.data()); 
+  auto end = Iterator(s,data.data(), true); 
+  size_t distance=std::distance(colIterator,end); 
+  
+  CHECK(size == distance);
+  
+  auto slice = view(Slice(0),Slice(0,size));
+  distance=std::distance(slice.begin(),slice.end());
+  CHECK(size == distance);
+  
+  
+  
+  
+}