From eb796c15585caaa383dcd031bbc7351f8a11bcd5 Mon Sep 17 00:00:00 2001
From: Cris Cecka <ccecka@seas.harvard.edu>
Date: Fri, 15 May 2015 14:47:13 -0700
Subject: [PATCH] Solid iterators, range type maps, examples.

---
 makefile     |  3 ++
 soa-range.cc | 97 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 100 insertions(+)
 create mode 100755 soa-range.cc

diff --git a/makefile b/makefile
index 9429a61..74b8a73 100644
--- a/makefile
+++ b/makefile
@@ -4,6 +4,9 @@ CXXFLAGS := -std=c++11 -Wall
 soa-iterator: soa-iterator.cc
 	$(CXX) $(CXXFLAGS) $< -o $@
 
+soa-range: soa-range.cc
+	$(CXX) $(CXXFLAGS) $< -o $@
+
 .PHONY: run
 run: soa-iterator
 	./$<
diff --git a/soa-range.cc b/soa-range.cc
new file mode 100755
index 0000000..045b14d
--- /dev/null
+++ b/soa-range.cc
@@ -0,0 +1,97 @@
+#include <iostream>
+#include <vector>
+#include <algorithm>
+
+#include <thrust/iterator/zip_iterator.h>
+
+// Printer helpers for library types
+
+std::ostream& operator<<(std::ostream& s, const thrust::tuple<double,double>& p) {
+  std::cout << "(" << thrust::get<0>(p) << ", " << thrust::get<1>(p) << ")";
+}
+
+// define the container
+class PointBuffer {
+
+ public:
+
+  typedef thrust::tuple<double,double> value_type;
+  typedef std::vector<double>::size_type size_type;
+
+  typedef typename std::vector<double>::iterator c_iterator;
+  typedef thrust::tuple<c_iterator, c_iterator> iter_pair;
+  typedef thrust::zip_iterator<iter_pair> iterator;
+
+  size_type size() const { return x.size(); }
+
+  void resize(size_type count) {
+    x.resize(count);
+    y.resize(count);
+  }
+
+  iterator begin() { return iterator(iter_pair(x.begin(), y.begin())); }
+  iterator end()   { return iterator(iter_pair(x.end(),   y.end()  )); }
+
+  c_iterator x_begin() { return x.begin(); }
+  c_iterator x_end() { return x.end(); }
+
+  c_iterator y_begin() { return y.begin(); }
+  c_iterator y_end() { return y.end(); }
+
+ private:
+  std::vector<double> x;
+  std::vector<double> y;
+};
+
+// Range access
+
+struct xrange {
+  xrange(PointBuffer& _pb) : pb(_pb) {}
+  typename PointBuffer::c_iterator begin() { return pb.x_begin(); }
+  typename PointBuffer::c_iterator end()   { return pb.x_end();   }
+  PointBuffer& pb;
+};
+
+struct yrange {
+  yrange(PointBuffer& _pb) : pb(_pb) {}
+  typename PointBuffer::c_iterator begin() { return pb.y_begin(); }
+  typename PointBuffer::c_iterator end()   { return pb.y_end();   }
+  PointBuffer& pb;
+};
+
+// Printers
+
+struct Printor {
+  template <typename T>
+  void operator()(const T& p) {
+    std::cout << p << std::endl;
+  }
+};
+
+template <typename Range>
+void print(Range&& r) {
+  for (const auto& i : r)
+    std::cout << i << std::endl;
+}
+
+int main() {
+  PointBuffer p;
+  p.resize(3);
+  double c = 0.0;
+
+  for (auto& x : xrange(p))
+    x = c++;
+  for (auto& y : yrange(p))
+    y = c++;
+
+  print(xrange(p));
+  print(yrange(p));
+  print(p);
+  std::cout << std::endl;
+
+  std::for_each(p.begin(), p.end(), Printor());
+
+  std::cout << "--- end of soa-iterator ---" << std::endl;
+
+  return 0;
+}