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"""number_conversion
The number_conversion module contains tools to convert features' data to
numbers.
"""
# IMPORT
import struct
# CLASSES
[docs]class NumberConversion(object):
"""This class helps to convert array of bytes to different formats, and
viceversa.
"""
[docs] @classmethod
def byte_to_uint8(self, data, index = 0):
"""Returns the short value of the unsigned byte value in position
"index".
Args:
data (str): Array of bytes that contains the value to convert.
index (int): Position of the value to convert.
Returns:
int: The corresponding numerical value.
"""
# Python 2
#return struct.unpack('B', data[index])[0]
# Python 3
return data[index]
[docs]class LittleEndian(object):
"""This class implements the conversion from array of bytes to different
formats, and viceversa, in Little Endian base order.
"""
[docs] @classmethod
def bytes_to_int16(self, data, start = 0):
"""Return the signed short value of two bytes of the array in Little
Endian base order.
Args:
data (str): Input array of bytes that contains the value to convert.
start (int): Start index in the array of the value to convert.
Returns:
The corresponding numerical value.
"""
# Python 2
#return struct.unpack('<h', struct.pack('cc', *data[start : start + 2]))[0]
# Python 3
return struct.unpack('<h', data[start : start + 2])[0]
[docs] @classmethod
def bytes_to_int32(self, data, start = 0):
"""Return the signed integer value of four bytes of the array in Little
Endian base order.
Args:
data (str): Input array of bytes that contains the value to convert.
start (int): Start index in the array of the value to convert.
Returns:
The corresponding numerical value.
"""
# Python 2
#return struct.unpack('<i', struct.pack('cccc', *data[start : start + 4]))[0]
# Python 3
return struct.unpack('<i', data[start : start + 4])[0]
[docs] @classmethod
def bytes_to_uint16(self, data, start = 0):
"""Return the unsigned short value of two bytes of the array in Little
Endian base order.
Args:
data (str): Input array of bytes that contains the value to convert.
start (int): Start index in the array of the value to convert.
Returns:
The corresponding numerical value.
"""
# Python 2
#return struct.unpack('<H', struct.pack('cc', *data[start : start + 2]))[0]
# Python 3
return struct.unpack('<H', data[start : start + 2])[0]
[docs] @classmethod
def bytes_to_uint32(self, data, start = 0):
"""Return the unsigned integer value of four bytes of the array in
Little Endian base order.
Args:
data (str): Input array of bytes that contains the value to convert.
start (int): Start index in the array of the value to convert.
Returns:
The corresponding numerical value.
"""
# Python 2
#return struct.unpack('<I', struct.pack('cccc', *data[start : start + 4]))[0]
# Python 3
return struct.unpack('<I', data[start : start + 4])[0]
[docs] @classmethod
def bytes_to_float(self, data, start = 0):
"""Return the floating point value of four bytes of the array in Little
Endian base order.
Args:
data (str): Input array of bytes that contains the value to convert.
start (int): Start index in the array of the value to convert.
Returns:
The corresponding numerical value.
"""
# Python 2
#return struct.unpack('<f', struct.pack('cccc', *data[start : start + 4]))[0]
# Python 3
return struct.unpack('<f', data[start : start + 4])[0]
[docs] @classmethod
def int16_to_bytes(self, value):
"""Return the two bytes array corresponding to the signed short value in
Little Endian base order.
Args:
value (int): Value to convert.
Returns:
The corresponding array of bytes.
"""
return struct.pack("<i", value)[0:2]
[docs] @classmethod
def int32_to_bytes(self, value):
"""Return the four bytes array corresponding to the signed integer value
in Little Endian base order.
Args:
value (int): Value to convert.
Returns:
The corresponding array of bytes.
"""
return struct.pack("<q", value)[0:4]
[docs] @classmethod
def uint16_to_bytes(self, value):
"""Return the two bytes array corresponding to the unsigned short value
in Little Endian base order.
Args:
value (int): Value to convert.
Returns:
The corresponding array of bytes.
"""
return struct.pack("<I", value)[0:2]
[docs] @classmethod
def uint32_to_bytes(self, value):
"""Return the four bytes array corresponding to the unsigned integer
value in Little Endian base order.
Args:
value (int): Value to convert.
Returns:
The corresponding array of bytes.
"""
return struct.pack("<Q", value)[0:4]
[docs] @classmethod
def float_to_bytes(self, value):
"""Return the four bytes array corresponding to the floating point value
in Little Endian base order.
Args:
value (float): Value to convert.
Returns:
The corresponding array of bytes.
"""
return struct.pack("<f", value)
[docs]class BigEndian(object):
"""This class implements the conversion from array of bytes to different
formats, and viceversa, in Big Endian base order.
"""
[docs] @classmethod
def bytes_to_int16(self, data, start = 0):
"""Return the signed short value of two bytes of the array in Big
Endian base order.
Args:
data (str): Input array of bytes that contains the value to convert.
start (int): Start index in the array of the value to convert.
Returns:
The corresponding numerical value.
"""
# Python 2
#return struct.unpack('>h', struct.pack('cc', *data[start : start + 2]))[0]
# Python 3
return struct.unpack('>h', data[start : start + 2])[0]
[docs] @classmethod
def bytes_to_int32(self, data, start = 0):
"""Return the signed integer value of four bytes of the array in Big
Endian base order.
Args:
data (str): Input array of bytes that contains the value to convert.
start (int): Start index in the array of the value to convert.
Returns:
The corresponding numerical value.
"""
# Python 2
#return struct.unpack('>i', struct.pack('cccc', *data[start : start + 4]))[0]
# Python 3
return struct.unpack('>i', data[start : start + 4])[0]
[docs] @classmethod
def bytes_to_uint16(self, data, start = 0):
"""Return the unsigned short value of two bytes of the array in Big
Endian base order.
Args:
data (str): Input array of bytes that contains the value to convert.
start (int): Start index in the array of the value to convert.
Returns:
The corresponding numerical value.
"""
# Python 2
#return struct.unpack('>H', struct.pack('cc', *data[start : start + 2]))[0]
# Python 3
return struct.unpack('>H', data[start : start + 2])[0]
[docs] @classmethod
def bytes_to_uint32(self, data, start = 0):
"""Return the unsigned integer value of four bytes of the array in Big
Endian base order.
Args:
data (str): Input array of bytes that contains the value to convert.
start (int): Start index in the array of the value to convert.
Returns:
The corresponding numerical value.
"""
# Python 2
#return struct.unpack('>I', struct.pack('cccc', *data[start : start + 4]))[0]
# Python 3
return struct.unpack('>I', data[start : start + 4])[0]
[docs] @classmethod
def bytes_to_float(self, data, start = 0):
"""Return the floating point value of four bytes of the array in Big
Endian base order.
Args:
data (str): Input array of bytes that contains the value to convert.
start (int): Start index in the array of the value to convert.
Returns:
The corresponding numerical value.
"""
# Python 2
#return struct.unpack('>f', struct.pack('cccc', *data[start : start + 4]))[0]
# Python 3
return struct.unpack('>f', data[start : start + 4])[0]
[docs] @classmethod
def int16_to_bytes(self, value):
"""Return the two bytes array corresponding to the signed short value in
Big Endian base order.
Args:
value (int): Value to convert.
Returns:
The corresponding array of bytes.
"""
return struct.pack(">i", value)[2:4]
[docs] @classmethod
def int32_to_bytes(self, value):
"""Return the four bytes array corresponding to the signed integer value
in Big Endian base order.
Args:
value (int): Value to convert.
Returns:
The corresponding array of bytes.
"""
return struct.pack(">q", value)[4:8]
[docs] @classmethod
def uint16_to_bytes(self, value):
"""Return the two bytes array corresponding to the unsigned short value
in Big Endian base order.
Args:
value (int): Value to convert.
Returns:
The corresponding array of bytes.
"""
return struct.pack(">I", value)[2:4]
[docs] @classmethod
def uint32_to_bytes(self, value):
"""Return the four bytes array corresponding to the unsigned integer
value in Big Endian base order.
Args:
value (int): Value to convert.
Returns:
The corresponding array of bytes.
"""
return struct.pack(">Q", value)[4:8]
[docs] @classmethod
def float_to_bytes(self, value):
"""Return the four bytes array corresponding to the floating point value
in Big Endian base order.
Args:
value (int): Value to convert.
Returns:
The corresponding array of bytes.
"""
return struct.pack(">f", value)