Helper function to create a hex dump from a ByteArray object in a WireShark Lua dissector

hexdump.lua

-- Author: Sean Pesce
-- References:
--     https://lua-users.org/wiki/HexDump
--     https://www.wireshark.org/docs/wsdg_html_chunked/lua_module_Tvb.html

function hex_dump(buf, print_addrs)
    if print_addrs == nil then
        print_addrs = false
    end
    local result = ""
    for byte = 0, buf:len() - 1, 16 do
        local chunk_sz = math.min(16, buf:len() - byte)
        local chunk = buf:subset(byte, chunk_sz)
        if print_addrs then
            -- Print the starting address of the line
            result = result .. string.format('%08X  ', byte)
        end
        for i = 0, chunk:len() - 1 do
            result = result .. string.format('%02X ', chunk:get_index(i))
        end
        -- Pad the remaining space if the chunk is less than 16 bytes
        result = result .. string.rep(' ', 3 * (16 - chunk:len()))
        -- Print ASCII representation
        result = result .. ' '
        for i = 0, chunk:len() - 1 do
            local char = chunk:get_index(i)
            if char >= 32 and char <= 126 then
                result = result .. string.char(char)
            else
                result = result .. '.'
            end
        end
        result = result .. "\n"
    end
    return result
end