46 lines
1.5 KiB
Python
Executable File
46 lines
1.5 KiB
Python
Executable File
# Copyright 2008-2018 pydicom authors. See LICENSE file for details.
|
|
"""Miscellaneous utility routines relating to hex and byte strings"""
|
|
|
|
from binascii import a2b_hex, b2a_hex
|
|
|
|
from pydicom.charset import default_encoding
|
|
|
|
|
|
def hex2bytes(hexstring: str | bytes) -> bytes:
|
|
"""Return bytestring for a string of hex bytes separated by whitespace
|
|
|
|
This is useful for creating specific byte sequences for testing, using
|
|
python's implied concatenation for strings with comments allowed.
|
|
|
|
Examples
|
|
--------
|
|
|
|
::
|
|
hex_string = (
|
|
"08 00 32 10 " # (0008,1032) SQ "Procedure Code Sequence"
|
|
"08 00 00 00 " # length 8
|
|
"fe ff 00 e0 " # (FFFE,E000) Item Tag
|
|
)
|
|
byte_string = hex2bytes(hex_string)
|
|
|
|
Note in the example that all lines except the first must
|
|
start with a space, alternatively the space could
|
|
end the previous line.
|
|
"""
|
|
|
|
# This works in both 3.x and 2.x because the first conditional evaluates to
|
|
# true in 2.x so the difference in bytes constructor doesn't matter
|
|
if isinstance(hexstring, bytes):
|
|
return a2b_hex(hexstring.replace(b" ", b""))
|
|
|
|
if isinstance(hexstring, str):
|
|
return a2b_hex(bytes(hexstring.replace(" ", ""), default_encoding))
|
|
|
|
raise TypeError("argument shall be bytes or string type")
|
|
|
|
|
|
def bytes2hex(byte_string: bytes) -> str:
|
|
"""Return a hex string representation of encoded bytes."""
|
|
s = b2a_hex(byte_string).decode()
|
|
return " ".join(s[i : i + 2] for i in range(0, len(s), 2))
|