1# Copyright 2018 Espressif Systems (Shanghai) PTE LTD
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7#     http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14#
15
16# Convenience functions for commonly used data type conversions
17import binascii
18
19from future.utils import tobytes
20
21
22def str_to_hexstr(string):
23    # Form hexstr by appending ASCII codes (in hex) corresponding to
24    # each character in the input string
25    return binascii.hexlify(tobytes(string)).decode()
26
27
28def hexstr_to_str(hexstr):
29    # Prepend 0 (if needed) to make the hexstr length an even number
30    if len(hexstr) % 2 == 1:
31        hexstr = '0' + hexstr
32    # Interpret consecutive pairs of hex characters as 8 bit ASCII codes
33    # and append characters corresponding to each code to form the string
34    return binascii.unhexlify(tobytes(hexstr)).decode()
35