diff --git a/python/flatbuffers/builder.py b/python/flatbuffers/builder.py index 09044575a..1e96d6fe7 100644 --- a/python/flatbuffers/builder.py +++ b/python/flatbuffers/builder.py @@ -21,8 +21,9 @@ from . import packer from . import compat from .compat import range_func from .compat import memoryview_type +from .compat import import_numpy, NumpyRequiredForThisFeature - +np = import_numpy() ## @file ## @addtogroup flatbuffers_python_api ## @{ @@ -441,6 +442,41 @@ class Builder(object): return self.EndVector(len(x)) + def CreateNumpyVector(self, x): + """CreateNumpyVector writes a numpy array into the buffer.""" + + if np is None: + # Numpy is required for this feature + raise NumpyRequiredForThisFeature("Numpy was not found.") + + if not isinstance(x, np.ndarray): + raise TypeError("non-numpy-ndarray passed to CreateNumpyVector") + + if x.dtype.kind not in ['b', 'i', 'u', 'f']: + raise TypeError("numpy-ndarray holds elements of unsupported datatype") + + if x.ndim > 1: + raise TypeError("multidimensional-ndarray passed to CreateNumpyVector") + + self.StartVector(x.itemsize, x.size, x.dtype.alignment) + + # Ensure little endian byte ordering + if x.dtype.str[0] == "<": + x_lend = x + else: + x_lend = x.byteswap(inplace=False) + + # Calculate total length + l = UOffsetTFlags.py_type(x_lend.itemsize * x_lend.size) + ## @cond FLATBUFFERS_INTERNAL + self.head = UOffsetTFlags.py_type(self.Head() - l) + ## @endcond + + # tobytes ensures c_contiguous ordering + self.Bytes[self.Head():self.Head()+l] = x_lend.tobytes(order='C') + + return self.EndVector(x.size) + ## @cond FLATBUFFERS_INTERNAL def assertNested(self): """ diff --git a/tests/py_test.py b/tests/py_test.py index e7c5b4806..268efbe7b 100644 --- a/tests/py_test.py +++ b/tests/py_test.py @@ -478,6 +478,266 @@ class TestByteLayout(unittest.TestCase): # 1-byte pad: self.assertBuilderEquals(b, [3, 0, 0, 0, 1, 2, 3, 0]) + def test_create_numpy_vector_int8(self): + try: + imp.find_module('numpy') + # if numpy exists, then we should be able to get the + # vector as a numpy array + import numpy as np + + # Systems endian: + b = flatbuffers.Builder(0) + x = np.array([1, 2, -3], dtype=np.int8) + b.CreateNumpyVector(x) + self.assertBuilderEquals(b, [ + 3, 0, 0, 0, # vector length + 1, 2, 256 - 3, 0 # vector value + padding + ]) + + # Reverse endian: + b = flatbuffers.Builder(0) + x_other_endian = x.byteswap().newbyteorder() + b.CreateNumpyVector(x_other_endian) + self.assertBuilderEquals(b, [ + 3, 0, 0, 0, # vector length + 1, 2, 256 - 3, 0 # vector value + padding + ]) + except ImportError: + b = flatbuffers.Builder(0) + x = 0 + assertRaises( + self, + lambda: b.CreateNumpyVector(x), + NumpyRequiredForThisFeature) + + def test_create_numpy_vector_uint16(self): + try: + imp.find_module('numpy') + # if numpy exists, then we should be able to get the + # vector as a numpy array + import numpy as np + + # Systems endian: + b = flatbuffers.Builder(0) + x = np.array([1, 2, 312], dtype=np.uint16) + b.CreateNumpyVector(x) + self.assertBuilderEquals(b, [ + 3, 0, 0, 0, # vector length + 1, 0, # 1 + 2, 0, # 2 + 312 - 256, 1, # 312 + 0, 0 # padding + ]) + + # Reverse endian: + b = flatbuffers.Builder(0) + x_other_endian = x.byteswap().newbyteorder() + b.CreateNumpyVector(x_other_endian) + self.assertBuilderEquals(b, [ + 3, 0, 0, 0, # vector length + 1, 0, # 1 + 2, 0, # 2 + 312 - 256, 1, # 312 + 0, 0 # padding + ]) + except ImportError: + b = flatbuffers.Builder(0) + x = 0 + assertRaises( + self, + lambda: b.CreateNumpyVector(x), + NumpyRequiredForThisFeature) + + def test_create_numpy_vector_int64(self): + try: + imp.find_module('numpy') + # if numpy exists, then we should be able to get the + # vector as a numpy array + import numpy as np + + # Systems endian: + b = flatbuffers.Builder(0) + x = np.array([1, 2, -12], dtype=np.int64) + b.CreateNumpyVector(x) + self.assertBuilderEquals(b, [ + 3, 0, 0, 0, # vector length + 1, 0, 0, 0, 0, 0, 0, 0, # 1 + 2, 0, 0, 0, 0, 0, 0, 0, # 2 + 256 - 12, 255, 255, 255, 255, 255, 255, 255 # -12 + ]) + + # Reverse endian: + b = flatbuffers.Builder(0) + x_other_endian = x.byteswap().newbyteorder() + b.CreateNumpyVector(x_other_endian) + self.assertBuilderEquals(b, [ + 3, 0, 0, 0, # vector length + 1, 0, 0, 0, 0, 0, 0, 0, # 1 + 2, 0, 0, 0, 0, 0, 0, 0, # 2 + 256 - 12, 255, 255, 255, 255, 255, 255, 255 # -12 + ]) + + except ImportError: + b = flatbuffers.Builder(0) + x = 0 + assertRaises( + self, + lambda: b.CreateNumpyVector(x), + NumpyRequiredForThisFeature) + + def test_create_numpy_vector_float32(self): + try: + imp.find_module('numpy') + # if numpy exists, then we should be able to get the + # vector as a numpy array + import numpy as np + + # Systems endian: + b = flatbuffers.Builder(0) + x = np.array([1, 2, -12], dtype=np.float32) + b.CreateNumpyVector(x) + self.assertBuilderEquals(b, [ + 3, 0, 0, 0, # vector length + 0, 0, 128, 63, # 1 + 0, 0, 0, 64, # 2 + 0, 0, 64, 193 # -12 + ]) + + # Reverse endian: + b = flatbuffers.Builder(0) + x_other_endian = x.byteswap().newbyteorder() + b.CreateNumpyVector(x_other_endian) + self.assertBuilderEquals(b, [ + 3, 0, 0, 0, # vector length + 0, 0, 128, 63, # 1 + 0, 0, 0, 64, # 2 + 0, 0, 64, 193 # -12 + ]) + + except ImportError: + b = flatbuffers.Builder(0) + x = 0 + assertRaises( + self, + lambda: b.CreateNumpyVector(x), + NumpyRequiredForThisFeature) + + def test_create_numpy_vector_float64(self): + try: + imp.find_module('numpy') + # if numpy exists, then we should be able to get the + # vector as a numpy array + import numpy as np + + # Systems endian: + b = flatbuffers.Builder(0) + x = np.array([1, 2, -12], dtype=np.float64) + b.CreateNumpyVector(x) + self.assertBuilderEquals(b, [ + 3, 0, 0, 0, # vector length + 0, 0, 0, 0, 0, 0, 240, 63, # 1 + 0, 0, 0, 0, 0, 0, 0, 64, # 2 + 0, 0, 0, 0, 0, 0, 40, 192 # -12 + ]) + + # Reverse endian: + b = flatbuffers.Builder(0) + x_other_endian = x.byteswap().newbyteorder() + b.CreateNumpyVector(x_other_endian) + self.assertBuilderEquals(b, [ + 3, 0, 0, 0, # vector length + 0, 0, 0, 0, 0, 0, 240, 63, # 1 + 0, 0, 0, 0, 0, 0, 0, 64, # 2 + 0, 0, 0, 0, 0, 0, 40, 192 # -12 + ]) + + except ImportError: + b = flatbuffers.Builder(0) + x = 0 + assertRaises( + self, + lambda: b.CreateNumpyVector(x), + NumpyRequiredForThisFeature) + + def test_create_numpy_vector_bool(self): + try: + imp.find_module('numpy') + # if numpy exists, then we should be able to get the + # vector as a numpy array + import numpy as np + + # Systems endian: + b = flatbuffers.Builder(0) + x = np.array([True, False, True], dtype=np.bool) + b.CreateNumpyVector(x) + self.assertBuilderEquals(b, [ + 3, 0, 0, 0, # vector length + 1, 0, 1, 0 # vector values + padding + ]) + + # Reverse endian: + b = flatbuffers.Builder(0) + x_other_endian = x.byteswap().newbyteorder() + b.CreateNumpyVector(x_other_endian) + self.assertBuilderEquals(b, [ + 3, 0, 0, 0, # vector length + 1, 0, 1, 0 # vector values + padding + ]) + + except ImportError: + b = flatbuffers.Builder(0) + x = 0 + assertRaises( + self, + lambda: b.CreateNumpyVector(x), + NumpyRequiredForThisFeature) + + def test_create_numpy_vector_reject_strings(self): + try: + imp.find_module('numpy') + # if numpy exists, then we should be able to get the + # vector as a numpy array + import numpy as np + + # Create String array + b = flatbuffers.Builder(0) + x = np.array(["hello", "fb", "testing"]) + assertRaises( + self, + lambda: b.CreateNumpyVector(x), + TypeError) + + except ImportError: + b = flatbuffers.Builder(0) + x = 0 + assertRaises( + self, + lambda: b.CreateNumpyVector(x), + NumpyRequiredForThisFeature) + + def test_create_numpy_vector_reject_object(self): + try: + imp.find_module('numpy') + # if numpy exists, then we should be able to get the + # vector as a numpy array + import numpy as np + + # Create String array + b = flatbuffers.Builder(0) + x = np.array([{"m": 0}, {"as": -2.1, 'c': 'c'}]) + assertRaises( + self, + lambda: b.CreateNumpyVector(x), + TypeError) + + except ImportError: + b = flatbuffers.Builder(0) + x = 0 + assertRaises( + self, + lambda: b.CreateNumpyVector(x), + NumpyRequiredForThisFeature) + def test_empty_vtable(self): b = flatbuffers.Builder(0) b.StartObject(0)