Squashed 'third_party/flatbuffers/' content from commit acc9990ab

Change-Id: I48550d40d78fea996ebe74e9723a5d1f910de491
git-subtree-dir: third_party/flatbuffers
git-subtree-split: acc9990abd2206491480291b0f85f925110102ea
diff --git a/python/flatbuffers/compat.py b/python/flatbuffers/compat.py
new file mode 100644
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+++ b/python/flatbuffers/compat.py
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+# Copyright 2016 Google Inc. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+""" A tiny version of `six` to help with backwards compability. Also includes
+ compatibility helpers for numpy. """
+
+import sys
+import imp
+
+PY2 = sys.version_info[0] == 2
+PY26 = sys.version_info[0:2] == (2, 6)
+PY27 = sys.version_info[0:2] == (2, 7)
+PY275 = sys.version_info[0:3] >= (2, 7, 5)
+PY3 = sys.version_info[0] == 3
+PY34 = sys.version_info[0:2] >= (3, 4)
+
+if PY3:
+    string_types = (str,)
+    binary_types = (bytes,bytearray)
+    range_func = range
+    memoryview_type = memoryview
+    struct_bool_decl = "?"
+else:
+    string_types = (unicode,)
+    if PY26 or PY27:
+        binary_types = (str,bytearray)
+    else:
+        binary_types = (str,)
+    range_func = xrange
+    if PY26 or (PY27 and not PY275):
+        memoryview_type = buffer
+        struct_bool_decl = "<b"
+    else:
+        memoryview_type = memoryview
+        struct_bool_decl = "?"
+
+# Helper functions to facilitate making numpy optional instead of required
+
+def import_numpy():
+    """
+    Returns the numpy module if it exists on the system,
+    otherwise returns None.
+    """
+    try:
+        imp.find_module('numpy')
+        numpy_exists = True
+    except ImportError:
+        numpy_exists = False
+
+    if numpy_exists:
+        # We do this outside of try/except block in case numpy exists
+        # but is not installed correctly. We do not want to catch an
+        # incorrect installation which would manifest as an
+        # ImportError.
+        import numpy as np
+    else:
+        np = None
+
+    return np
+
+
+class NumpyRequiredForThisFeature(RuntimeError):
+    """
+    Error raised when user tries to use a feature that
+    requires numpy without having numpy installed.
+    """
+    pass
+
+
+# NOTE: Future Jython support may require code here (look at `six`).