From 976d44b1d90e2e93fa756ac703977fd2feea9c77 Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Fri, 8 Mar 2019 09:38:13 +1100
Subject: [PATCH] region: use half-open range for region::step

---
 region.hpp      | 18 +++++++++++-------
 test/region.cpp |  8 ++++----
 2 files changed, 15 insertions(+), 11 deletions(-)

diff --git a/region.hpp b/region.hpp
index 93633efa..025e2116 100644
--- a/region.hpp
+++ b/region.hpp
@@ -3,12 +3,11 @@
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  *
- * Copyright 2010-2017 Danny Robson <danny@nerdcruft.net>
+ * Copyright 2010-2019 Danny Robson <danny@nerdcruft.net>
  */
 
 
-#ifndef CRUFT_UTIL_REGION_HPP
-#define CRUFT_UTIL_REGION_HPP
+#pragma once
 
 #include "./extent.hpp"
 #include "./point.hpp"
@@ -156,7 +155,7 @@ namespace cruft {
                 cursor[0] += 1;
 
                 for (size_t s = 0; s < S-1; ++s) {
-                    if (cursor[s] <= hi[s])
+                    if (cursor[s] < hi[s])
                         return *this;
 
                     cursor[s] = lo[s];
@@ -173,10 +172,17 @@ namespace cruft {
             point_t cursor, lo, hi;
         };
 
+
+        /// Returns an iterator that provides successive points across the
+        /// region.
+        ///
+        /// The points are in the half open range [p, p+e). ie, the
+        /// 'bottom-right' corner will never be returned. If you need this
+        /// behaviour then construct a larger range.
         auto step (void) const
         {
             point_t last = p;
-            last[S-1] = (p + e)[S-1] + 1;
+            last[S-1] = (p + e)[S-1];
 
             return cruft::view {
                 iterator { p,    p + e },
@@ -296,5 +302,3 @@ namespace cruft {
     template <size_t S, typename T>
     std::ostream& operator<< (std::ostream&, const cruft::region<S,T>&);
 }
-
-#endif
diff --git a/test/region.cpp b/test/region.cpp
index b1c87c3e..fae3ac98 100644
--- a/test/region.cpp
+++ b/test/region.cpp
@@ -84,13 +84,13 @@ main (int, char **)
     // ensure make_region covers the expected values
     {
         const cruft::region2i REGION {
-            cruft::point2i { -1, 1 },
-            cruft::point2i {  1, 2 }
+            cruft::point2i { 0, 0 },
+            cruft::point2i { 3, 2 }
         };
 
         const cruft::point2i EXPECTED[] = {
-            { -1,  1 }, {  0,  1 }, {  1,  1 },
-            { -1,  2 }, {  0,  2 }, {  1,  2 },
+            { 0, 0 }, { 1, 0 }, { 2, 0 },
+            { 0, 1 }, { 1, 1 }, { 2, 1 },
         };
 
         std::vector<cruft::point2i> values;