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BUG: Fix astype for structured array fields of different byte order. #5481

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Merged
charris merged 1 commit into from
Jan 22, 2015
Merged

BUG: Fix astype for structured array fields of different byte order. #5481

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64 changes: 63 additions & 1 deletion numpy/core/src/multiarray/convert_datatype.c
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Original file line number Diff line number Diff line change
Expand Up @@ -634,6 +634,52 @@ static npy_bool
PyArray_CanCastTypeTo_impl(PyArray_Descr *from, PyArray_Descr *to,
NPY_CASTING casting);

/*
* Compare two field dictionaries for castability.
*
* Return 1 if 'field1' can be cast to 'field2' according to the rule
* 'casting', 0 if not.
*
* Castabiliy of field dictionaries is defined recursively: 'field1' and
* 'field2' must have the same field names (possibly in different
* orders), and the corresponding field types must be castable according
* to the given casting rule.
*/
static int
can_cast_fields(PyObject *field1, PyObject *field2, NPY_CASTING casting)
{
Py_ssize_t ppos;
PyObject *key;
PyObject *tuple1, *tuple2;

if (field1 == field2) {
return 1;
}
if (field1 == NULL || field2 == NULL) {
return 0;
}
if (PyDict_Size(field1) != PyDict_Size(field2)) {
return 0;
}

/* Iterate over all the fields and compare for castability */
ppos = 0;
while (PyDict_Next(field1, &ppos, &key, &tuple1)) {
if ((tuple2 = PyDict_GetItem(field2, key)) == NULL) {
return 0;
}
/* Compare the dtype of the field for castability */
if (!PyArray_CanCastTypeTo(
(PyArray_Descr *)PyTuple_GET_ITEM(tuple1, 0),
(PyArray_Descr *)PyTuple_GET_ITEM(tuple2, 0),
casting)) {
return 0;
}
}

return 1;
}

/*NUMPY_API
* Returns true if data of type 'from' may be cast to data of type
* 'to' according to the rule 'casting'.
Expand Down Expand Up @@ -687,7 +733,6 @@ PyArray_CanCastTypeTo_impl(PyArray_Descr *from, PyArray_Descr *to,
else if (PyArray_EquivTypenums(from->type_num, to->type_num)) {
/* For complicated case, use EquivTypes (for now) */
if (PyTypeNum_ISUSERDEF(from->type_num) ||
PyDataType_HASFIELDS(from) ||
from->subarray != NULL) {
int ret;

Expand Down Expand Up @@ -715,6 +760,23 @@ PyArray_CanCastTypeTo_impl(PyArray_Descr *from, PyArray_Descr *to,
return ret;
}

if (PyDataType_HASFIELDS(from)) {
switch (casting) {
case NPY_EQUIV_CASTING:
case NPY_SAFE_CASTING:
case NPY_SAME_KIND_CASTING:
/*
* `from' and `to' must have the same fields, and
* corresponding fields must be (recursively) castable.
*/
return can_cast_fields(from->fields, to->fields, casting);

case NPY_NO_CASTING:
default:
return PyArray_EquivTypes(from, to);
}
}

switch (from->type_num) {
case NPY_DATETIME: {
PyArray_DatetimeMetaData *meta1, *meta2;
Expand Down
41 changes: 13 additions & 28 deletions numpy/core/src/multiarray/multiarraymodule.c
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Expand Up @@ -1410,43 +1410,28 @@ array_putmask(PyObject *NPY_UNUSED(module), PyObject *args, PyObject *kwds)
static int
_equivalent_fields(PyObject *field1, PyObject *field2) {

Py_ssize_t ppos;
PyObject *key;
PyObject *tuple1, *tuple2;
int same, val;

if (field1 == field2) {
return 1;
}
if (field1 == NULL || field2 == NULL) {
return 0;
}

if (PyDict_Size(field1) != PyDict_Size(field2)) {
return 0;
#if defined(NPY_PY3K)
val = PyObject_RichCompareBool(field1, field2, Py_EQ);
if (val != 1 || PyErr_Occurred()) {
#else
val = PyObject_Compare(field1, field2);
if (val != 0 || PyErr_Occurred()) {
#endif
same = 0;
}

/* Iterate over all the fields and compare for equivalency */
ppos = 0;
while (PyDict_Next(field1, &ppos, &key, &tuple1)) {
if ((tuple2 = PyDict_GetItem(field2, key)) == NULL) {
return 0;
}
/* Compare the dtype of the field for equivalency */
if (!PyArray_CanCastTypeTo((PyArray_Descr *)PyTuple_GET_ITEM(tuple1, 0),
(PyArray_Descr *)PyTuple_GET_ITEM(tuple2, 0),
NPY_EQUIV_CASTING)) {
return 0;
}
/* Compare the byte position of the field */
if (PyObject_RichCompareBool(PyTuple_GET_ITEM(tuple1, 1),
PyTuple_GET_ITEM(tuple2, 1),
Py_EQ) != 1) {
PyErr_Clear();
return 0;
}
else {
same = 1;
}

return 1;
PyErr_Clear();
return same;
}

/*
Expand Down
63 changes: 63 additions & 0 deletions numpy/core/tests/test_multiarray.py
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Original file line number Diff line number Diff line change
Expand Up @@ -289,6 +289,10 @@ def test_construction(self):
d2 = dtype('f8')
assert_equal(d2, dtype(float64))

def test_byteorders(self):
self.assertNotEqual(dtype('<i4'), dtype('>i4'))
self.assertNotEqual(dtype([('a', '<i4')]), dtype([('a', '>i4')]))

class TestZeroRank(TestCase):
def setUp(self):
self.d = array(0), array('x', object)
Expand Down Expand Up @@ -688,6 +692,65 @@ def test_subarray_comparison(self):
b = np.array([(5, 43), (10, 1)], dtype=[('a', '<i8'), ('b', '>f8')])
assert_equal(a == b, [False, True])

def test_casting(self):
# Check that casting a structured array to change its byte order
# works
a = np.array([(1,)], dtype=[('a', '<i4')])
assert_(np.can_cast(a.dtype, [('a', '>i4')], casting='unsafe'))
b = a.astype([('a', '>i4')])
assert_equal(b, a.byteswap().newbyteorder())
assert_equal(a['a'][0], b['a'][0])

# Check that equality comparison works on structured arrays if
# they are 'equiv'-castable
a = np.array([(5, 42), (10, 1)], dtype=[('a', '>i4'), ('b', '<f8')])
b = np.array([(42, 5), (1, 10)], dtype=[('b', '>f8'), ('a', '<i4')])
assert_(np.can_cast(a.dtype, b.dtype, casting='equiv'))
assert_equal(a == b, [True, True])

# Check that 'equiv' casting can reorder fields and change byte
# order
assert_(np.can_cast(a.dtype, b.dtype, casting='equiv'))
c = a.astype(b.dtype, casting='equiv')
assert_equal(a == c, [True, True])

# Check that 'safe' casting can change byte order and up-cast
# fields
t = [('a', '<i8'), ('b', '>f8')]
assert_(np.can_cast(a.dtype, t, casting='safe'))
c = a.astype(t, casting='safe')
assert_equal((c == np.array([(5, 42), (10, 1)], dtype=t)),
[True, True])

# Check that 'same_kind' casting can change byte order and
# change field widths within a "kind"
t = [('a', '<i4'), ('b', '>f4')]
assert_(np.can_cast(a.dtype, t, casting='same_kind'))
c = a.astype(t, casting='same_kind')
assert_equal((c == np.array([(5, 42), (10, 1)], dtype=t)),
[True, True])

# Check that casting fails if the casting rule should fail on
# any of the fields
t = [('a', '>i8'), ('b', '<f4')]
assert_(not np.can_cast(a.dtype, t, casting='safe'))
assert_raises(TypeError, a.astype, t, casting='safe')
t = [('a', '>i2'), ('b', '<f8')]
assert_(not np.can_cast(a.dtype, t, casting='equiv'))
assert_raises(TypeError, a.astype, t, casting='equiv')
t = [('a', '>i8'), ('b', '<i2')]
assert_(not np.can_cast(a.dtype, t, casting='same_kind'))
assert_raises(TypeError, a.astype, t, casting='same_kind')
assert_(not np.can_cast(a.dtype, b.dtype, casting='no'))
assert_raises(TypeError, a.astype, b.dtype, casting='no')

# Check that non-'unsafe' casting can't change the set of field names
for casting in ['no', 'safe', 'equiv', 'same_kind']:
t = [('a', '>i4')]
assert_(not np.can_cast(a.dtype, t, casting=casting))
t = [('a', '>i4'), ('b', '<f8'), ('c', 'i4')]
assert_(not np.can_cast(a.dtype, t, casting=casting))


class TestBool(TestCase):
def test_test_interning(self):
Expand Down