Unsigned integer 7-bit encoder and decoder in Python

	#!/usr/bin/evn python
	# -*- coding: utf8 -*-
	def encode_to_7bit(value):
	"""
	Encode unsigned int to 7-bit str data
	"""
	data = []
	number = abs(value)
	while number >= 0x80:
	data.append((number | 0x80) & 0xff)
	number >>= 7
	data.append(number & 0xff)
	return ''.join(chr(char) for char in data)
	def decode_from_7bit(data):
	"""
	Decode 7-bit encoded int from str data
	"""
	result = 0
	for index, char in enumerate(data):
	byte_value = ord(char)
	result |= (byte_value & 0x7f) << (7 * index)
	if byte_value & 0x80 == 0:
	break
	return result
	def test():
	"""
	Test encoding and decoding
	"""
	value = 0
	res = encode_to_7bit(value)
	assert res == '\x00', 'Invalid encoding of %s' % value
	value = 127
	res = encode_to_7bit(value)
	assert res == '\x7f', 'Invalid encoding of %s' % value
	value = 256
	res = encode_to_7bit(value)
	assert res == '\x80\x02', 'Invalid encoding of %s' % value
	value = 0
	res = encode_to_7bit(value)
	assert decode_from_7bit(encode_to_7bit(value)) == value, 'Invalid decoding of %s' % value
	value = 42
	res = encode_to_7bit(value)
	assert decode_from_7bit(encode_to_7bit(value)) == value, 'Invalid decoding of %s' % value
	value = 1082376495
	res = encode_to_7bit(value)
	assert decode_from_7bit(encode_to_7bit(value)) == value, 'Invalid decoding of %s' % value
	if __name__ == '__main__':
	try:
	test()
	print('OK')
	except Exception as ex:
	print('FAILED: %s' % ex)

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