在Lua Dissector中将HEX转换为ASCII

Question

I'm trying to take HEX bytes and display them as their ASCII values. If someone could point me reasonably firmly in the right direction I'd be obliged. Tried any number of uint-type commands, and working with buffer(x, 2) as an argument.

Answer 1

I'm not sure what you mean by hex bytes , but the relevant functions are:

• string.byte , which converts chars to numerical codes

• string.char , which converts numerical codes to chars

Answer 2

For a single character in hexadecimal, you can use string.byte as mentioned by lhf. For longer sequences, you can create a loop in Lua, but that is not very efficient since it involves a lot of copying.

Since Wireshark 1.11.3 there is a Struct.fromhex function that converts a string of hexadecimal characters to the binary equivalent.

Example:

-- From hex to bytes (with no separators)
assert(Struct.fromhex("5753") == "WS")
-- From hex to bytes (using a single space as separator)
assert(Struct.fromhex("57 53", " ") == "WS")

Similarly, there is a Struct.tohex function that converts from bytes to hex.