From baf8ded43d7c28c5a4ba6dc96a879ee3551a6e6c Mon Sep 17 00:00:00 2001
From: Danny Robson <danny@nerdcruft.net>
Date: Fri, 15 Jun 2012 16:38:57 +1000
Subject: [PATCH] Add UNIT and MAX region objects

---
 region.cpp      | 32 ++++++++++++++++++++++++++------
 region.hpp      |  3 +++
 test/region.cpp |  6 ++++++
 3 files changed, 35 insertions(+), 6 deletions(-)

diff --git a/region.cpp b/region.cpp
index dbe7d76d..9ca19a9b 100644
--- a/region.cpp
+++ b/region.cpp
@@ -39,6 +39,7 @@ region<T>::region (T _x, T _y, size_type _w, size_type _h):
     w (_w),
     h (_h)
 {
+    DEBUG_ONLY (sanity ());
 }
 
 
@@ -111,15 +112,15 @@ region<T>::contains (const point<2> &p) const {
 }
 
 
+// FIXME: This will fail with an actual infinite range (NaNs will be generated
+// in the conditionals).
 template <typename T>
 bool
 region<T>::overlaps (const region<T> &rhs) const {
-    //return !overlap (rhs).empty ();
-    
-    return x     < sign_cast<T> (rhs.w) + rhs.x && 
-           rhs.x < sign_cast<T> (    w) +     x &&
-           y     < sign_cast<T> (rhs.h) + rhs.y &&
-           rhs.y < sign_cast<T> (    h) +     y;
+    return  x     < rhs.x + rhs.w &&
+            rhs.x < x     +     w &&
+            y     < rhs.y + rhs.h &&
+            rhs.y < y     +     h;
 }
 
 
@@ -156,6 +157,8 @@ region<T>::operator== (const region& rhs) const
 template <typename T>
 void
 region<T>::sanity (void) const {
+    CHECK_SOFT (w > 0);
+    CHECK_SOFT (h > 0);
     static_assert(!std::is_floating_point<T>::value,
                   "Floating point types need width and height checks");
 }
@@ -229,6 +232,22 @@ namespace util {
 }
 
 
+//-----------------------------------------------------------------------------
+template <typename T>
+const region<T>
+region<T>::MAX (std::numeric_limits<T>::lowest (),
+                std::numeric_limits<T>::lowest (),
+                std::numeric_limits<T>::has_infinity ? std::numeric_limits<T>::infinity () :
+                                                       std::numeric_limits<T>::max (),
+                std::numeric_limits<T>::has_infinity ? std::numeric_limits<T>::infinity () :
+                                                       std::numeric_limits<T>::max ());
+
+
+template  <typename T>
+const region<T>
+region<T>::UNIT (0, 0, 1, 1);
+
+
 //-----------------------------------------------------------------------------
 template <typename T>
 std::ostream&
@@ -244,6 +263,7 @@ namespace util {
     template struct region<int64_t>;
     template struct region<uint32_t>;
     template struct region<uint64_t>;
+    template struct region<float>;
     template struct region<double>;
 
     template std::ostream& operator<< (std::ostream&, const region< int32_t>&);
diff --git a/region.hpp b/region.hpp
index 16b6c981..231d23ea 100644
--- a/region.hpp
+++ b/region.hpp
@@ -62,6 +62,9 @@ namespace util {
         bool operator !=(const region<T>& rhs) const
             { return !(*this == rhs); }
 
+        static const region<T> MAX;
+        static const region<T> UNIT;
+
         void sanity (void) const;
 
 #if 0
diff --git a/test/region.cpp b/test/region.cpp
index aaf7456f..afd7427c 100644
--- a/test/region.cpp
+++ b/test/region.cpp
@@ -14,6 +14,12 @@ main (int, char **) {
          CHECK_HARD (!a.overlaps (b));
     }
 
+    CHECK_HARD (region<double>::MAX.overlaps (region<double>::UNIT));
+    CHECK_HARD (region< float>::MAX.overlaps (region< float>::UNIT));
+
+    CHECK_EQ (region<double>::UNIT.area (), 1.0);
+    CHECK_EQ (region< float>::UNIT.area (), 1.0f);
+
     CHECK_HARD (region<int> (0, 0, 2, 2).includes (point2(1.0, 1.0)));
     CHECK_HARD (region<int> (0, 0, 2, 2).includes (point2(0.0, 0.0)));
     CHECK_HARD (region<int> (0, 0, 2, 2).includes (point2(2.0, 2.0)));