# Copyright 2017-2018 The dm_control Authors.

#

# 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.

# ============================================================================

"""Various helper functions and classes."""

import functools

import sys

import mujoco

import numpy as np

# Environment variable that can be used to override the default path to the

# MuJoCo shared library.

ENV_MJLIB_PATH = "MJLIB_PATH"

DEFAULT_ENCODING = sys.getdefaultencoding()

def to_binary_string(s):

"""Convert text string to binary."""

if isinstance(s, bytes):

return s

return s.encode(DEFAULT_ENCODING)

def to_native_string(s):

"""Convert a text or binary string to the native string format."""

if isinstance(s, bytes):

return s.decode(DEFAULT_ENCODING)

else:

return s

def get_mjlib():

return mujoco

@functools.wraps(np.ctypeslib.ndpointer)

def ndptr(*args, **kwargs):

"""Wraps `np.ctypeslib.ndpointer` to allow passing None for NULL pointers."""

base = np.ctypeslib.ndpointer(*args, **kwargs)

def from_param(_, obj):

if obj is None:

return obj

else:

return base.from_param(obj)

return type(base.__name__, (base,), {"from_param": classmethod(from_param)})