[geos-commits] [SCM] GEOS branch master updated. 9924c15fc0611e2e49d5665b18122bfa4c5fe1c0

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- Log -----------------------------------------------------------------
commit 9924c15fc0611e2e49d5665b18122bfa4c5fe1c0
Author: Daniel Baston <dbaston at gmail.com>
Date:   Fri Sep 27 14:46:36 2019 -0400

    Ignore z in Coordinate::HashCode
    
    Including z was inconsistent with the behavior of the equality operator,
    and caused equivalent coordinates to be hashed into different bins.
    
    Identified by Raul Marín, debugged by Paul Ramsey.

diff --git a/include/geos/geom/Coordinate.inl b/include/geos/geom/Coordinate.inl
index 7accf73..983931e 100644
--- a/include/geos/geom/Coordinate.inl
+++ b/include/geos/geom/Coordinate.inl
@@ -143,7 +143,7 @@ INLINE size_t
 Coordinate::HashCode::operator()(const geos::geom::Coordinate &c) const {
     size_t h = std::hash<double>{}(c.x);
     h ^= std::hash<double>{}(c.y) << 1;
-    h ^= std::hash<double>{}(c.z) << 1;
+    // z ordinate ignored for consistency with operator==
     return h;
 }
 
diff --git a/tests/unit/geom/CoordinateTest.cpp b/tests/unit/geom/CoordinateTest.cpp
index 1b28c3b..e0d64e2 100644
--- a/tests/unit/geom/CoordinateTest.cpp
+++ b/tests/unit/geom/CoordinateTest.cpp
@@ -6,6 +6,7 @@
 #include <geos/geom/Coordinate.h>
 // std
 #include <cmath>
+#include <unordered_set>
 
 namespace tut {
 //
@@ -196,5 +197,26 @@ void object::test<9>
     ensure(0 != std::isnan(null_coord.z));
 }
 
+template<>
+template<>
+void object::test<10>
+()
+{
+    using geos::geom::Coordinate;
+
+    std::unordered_set<Coordinate, Coordinate::HashCode> coords;
+
+    coords.emplace(1, 2);
+    ensure_equals(coords.size(), 1ul);
+
+    coords.emplace(2, 1);
+    ensure_equals(coords.size(), 2ul);
+
+    // hash function defined consistently with equality operator
+    // and considers X and Y only
+    coords.emplace(1, 2, 3);
+    ensure_equals(coords.size(), 2ul);
+}
+
 } // namespace tut
 
diff --git a/tests/xmltester/tests/issue/issue-geos-990.xml b/tests/xmltester/tests/issue/issue-geos-990.xml
new file mode 100644
index 0000000..ae70347
--- /dev/null
+++ b/tests/xmltester/tests/issue/issue-geos-990.xml
@@ -0,0 +1,19 @@
+<run>
+<precisionModel type="FLOATING" />
+<case>
+<desc>
+Difference of two 3D geometries
+</desc>
+<a>
+LINESTRING(0 0,0 10,10 10,10 0,0 0)
+</a>
+<b>
+GEOMETRYCOLLECTION Z (GEOMETRYCOLLECTION Z (MULTILINESTRING Z ((0 0 10,10 0 20),(10 0 20,10 10 30)),LINESTRING Z (0 10 20,10 10 30)),LINESTRING Z (0 0 10,0 10 20))'::geometry
+</b>
+<test>
+<op name="difference" arg1="A" arg2="B">
+LINESTRING EMPTY
+</op>
+</test>
+</case>
+</run>

-----------------------------------------------------------------------

Summary of changes:
 include/geos/geom/Coordinate.inl               |  2 +-
 tests/unit/geom/CoordinateTest.cpp             | 22 ++++++++++++++++++++++
 tests/xmltester/tests/issue/issue-geos-990.xml | 19 +++++++++++++++++++
 3 files changed, 42 insertions(+), 1 deletion(-)
 create mode 100644 tests/xmltester/tests/issue/issue-geos-990.xml


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