ENH: Implement hash, eq, neq

pygeos/test/common.py

@@ -29,6 +29,7 @@
 empty_point = pygeos.Geometry("POINT EMPTY")
 empty_line_string = pygeos.Geometry("LINESTRING EMPTY")
 empty = pygeos.Geometry("GEOMETRYCOLLECTION EMPTY")
+point_nan = pygeos.points(np.nan, np.nan)
 
 all_types = (
     point,

pygeos/test/test_geometry.py

@@ -3,6 +3,7 @@
 import pytest
 
 from .common import point
+from .common import point_nan
 from .common import line_string
 from .common import linear_ring
 from .common import polygon
@@ -166,3 +167,51 @@ def test_adapt_ptr_raises():
     point = pygeos.Geometry("POINT (2 2)")
     with pytest.raises(AttributeError):
         point._ptr += 1
+
+
+@pytest.mark.parametrize("geom", all_types + (pygeos.points(np.nan, np.nan),))
+def test_hash_same_equal(geom):
+    assert hash(geom) == hash(pygeos.apply(geom, lambda x: x))
+
+
+@pytest.mark.parametrize("geom", all_types[:-1])
+def test_hash_same_not_equal(geom):
+    assert hash(geom) != hash(pygeos.apply(geom, lambda x: x + 1))
+
+
+@pytest.mark.parametrize("geom", all_types)
+def test_eq(geom):
+    assert geom == pygeos.apply(geom, lambda x: x)
+
+
+@pytest.mark.parametrize("geom", all_types[:-1])
+def test_neq(geom):
+    assert geom != pygeos.apply(geom, lambda x: x + 1)
+
+
+@pytest.mark.parametrize("geom", all_types)
+def test_set_unique(geom):
+    a = {geom, pygeos.apply(geom, lambda x: x)}
+    assert len(a) == 1
+
+
+def test_eq_nan():
+    assert point_nan != point_nan
+
+
+def test_neq_nan():
+    assert not (point_nan == point_nan)
+
+
+def test_set_nan():
+    # As NaN != NaN, you can have multiple "NaN" points in a set
+    # set([float("nan"), float("nan")]) also returns a set with 2 elements
+    a = set(pygeos.points([[np.nan, np.nan]] * 10))
+    assert len(a) == 10  # different objects: NaN != NaN
+
+
+def test_set_nan_same_objects():
+    # You can't put identical objects in a set.
+    # x = float("nan"); set([x, x]) also retuns a set with 1 element
+    a = set([point_nan] * 10)
+    assert len(a) == 1

src/pygeom.c

@@ -76,6 +76,70 @@ static PyObject *GeometryObject_str(GeometryObject *self)
     return GeometryObject_ToWKT(self, "%s");
 }
 
+static Py_hash_t GeometryObject_hash(GeometryObject *self)
+{
+    void *context = geos_context[0];
+    unsigned char *wkb;
+    size_t size;
+    Py_hash_t x;
+
+    if (self->ptr == NULL) {
+        return -1;
+    }
+    GEOSWKBWriter *writer = GEOSWKBWriter_create_r(context);
+    if (writer == NULL) {
+        return -1;
+    }
+
+    GEOSWKBWriter_setOutputDimension_r(context, writer, 3);
+    GEOSWKBWriter_setIncludeSRID_r(context, writer, 1);
+    wkb = GEOSWKBWriter_write_r(context, writer, self->ptr, &size);
+    GEOSWKBWriter_destroy_r(context, writer);
+    if (wkb == NULL) {
+        return -1;
+    }
+    x = PyHash_GetFuncDef()->hash(wkb, size);
+    if (x == -1) {
+        x = -2;
+    } else {
+        x ^= 374761393UL;  // to make the result distinct from the actual WKB hash //
+    }
+    GEOSFree_r(context, wkb);
+    return x;
+}
+
+static PyObject *GeometryObject_richcompare(GeometryObject *self, PyObject *other, int op) {
+  PyObject *result = NULL;
+  void *context = geos_context[0];
+  if (Py_TYPE(self)->tp_richcompare != Py_TYPE(other)->tp_richcompare) {
+      result = Py_NotImplemented;
+  } else {
+      GeometryObject *other_geom = (GeometryObject *) other;
+      switch (op) {
+      case Py_LT:
+        result = Py_NotImplemented;
+        break;
+      case Py_LE:
+        result = Py_NotImplemented;
+        break;
+      case Py_EQ:
+        result = GEOSEqualsExact_r(context, self->ptr, other_geom->ptr, 0) ? Py_True : Py_False;
+        break;
+      case Py_NE:
+        result = GEOSEqualsExact_r(context, self->ptr, other_geom->ptr, 0) ? Py_False : Py_True;
+        break;
+      case Py_GT:
+        result = Py_NotImplemented;
+        break;
+      case Py_GE:
+        result = Py_NotImplemented;
+        break;
+    }
+  }
+  Py_XINCREF(result);
+  return result;
+}
+
 static PyObject *GeometryObject_FromWKT(PyTypeObject *type, PyObject *value)
 {
     void *context_handle = geos_context[0];
@@ -143,6 +207,8 @@ PyTypeObject GeometryType = {
     .tp_members = GeometryObject_members,
     .tp_methods = GeometryObject_methods,
     .tp_repr = (reprfunc) GeometryObject_repr,
+    .tp_hash = (hashfunc) GeometryObject_hash,
+    .tp_richcompare = (richcmpfunc) GeometryObject_richcompare,
     .tp_str = (reprfunc) GeometryObject_str,
 };
 

src/ufuncs.c

@@ -1086,7 +1086,7 @@ static void from_wkt_func(char **args, npy_intp *dimensions,
     GEOSWKTReader *reader;
     const char *wkt;
 
-    /* Create the WKB reader */
+    /* Create the WKT reader */
     reader = GEOSWKTReader_create_r(context_handle);
     if (reader == NULL) {
         return;