From af11d7c730631101e97b4f54f96a166a02634b6a Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Wed, 8 Apr 2015 19:00:33 +1000
Subject: [PATCH] extent: add contract methods

---
 extent.cpp | 20 +++++++++++++++++++-
 extent.hpp |  2 ++
 2 files changed, 21 insertions(+), 1 deletion(-)

diff --git a/extent.cpp b/extent.cpp
index b12930a4..f7054fb9 100644
--- a/extent.cpp
+++ b/extent.cpp
@@ -77,7 +77,25 @@ template <size_t S, typename T>
 util::extent<S,T>
 util::extent<S,T>::expanded (T t) const
 {
-    return expanded (util::vector<S,T> {t});
+    return *this + util::vector<S,T> {t};
+}
+
+
+//-----------------------------------------------------------------------------
+template <size_t S, typename T>
+util::extent<S,T>
+util::extent<S,T>::contracted (vector<S,T> t) const
+{
+    return *this - t;
+}
+
+
+//-----------------------------------------------------------------------------
+template <size_t S, typename T>
+util::extent<S,T>
+util::extent<S,T>::contracted (T t) const
+{
+    return *this - vector<S,T> {-t};
 }
 
 
diff --git a/extent.hpp b/extent.hpp
index c6014e99..ce47b157 100644
--- a/extent.hpp
+++ b/extent.hpp
@@ -45,6 +45,8 @@ namespace util {
 
         extent expanded (vector<S,T>) const;
         extent expanded (T) const;
+        extent contracted (vector<S,T>) const;
+        extent contracted (T) const;
 
         bool empty (void) const;