Monday, January 23, 2012
A disconnect
R stops by my desk and drops off a new toy unit to play
with test. It's a network device you can plug a POTS line into and make calls over the
Internet. I guess we're testing the toy to play with unit to see
if our phone network features work with it.
It's a nice looking device and as R hands it to me, I see that's it still
on (yes, it comes with both an internal battery and a wall-wart). The tests
aren't complicated, but I do need to read the manual to figure out how to
run a few of them (involving conference calling, and forwarding phone
calls elsewhere). R also hands me the box the toy to play with
unit came in.
As I searched through the box for the manual, I come across a USB cable, still in it plastic wrap.
Okay, the unit comes with a USB port; what doesn't these days? I then find the manual
and start flipping through it. There's the diagram of the toy to play
with unit with a description of each port and button on it. I notice
the USB port has a note:
NOTE: Never place a USB-based device into the USB port of the XXXX XXXXX XXXXXXX under any circumstances. Doing so may damage the device and negate its warranty. The port was designed for diagnostic purposes only; it is not intended for customer use.
So, not only is there no sticker over the USB port saying “removal of this sticket voids warranty” but they give you a USB cable not to plug into it!
Methinks there is a disconnect between manufactoring and packaging at the
factory that makes these toys to play with units.
99 ways to program a hex, Part 15: Lua
I'm still taking a break from C, and today's version is in Lua.
#!/usr/bin/env lua
-- ***************************************************************
--
-- Copyright 2012 by Sean Conner. All Rights Reserved.
--
-- This program is free software: you can redistribute it and/or modify
-- it under the terms of the GNU General Public License as published by
-- the Free Software Foundation, either version 3 of the License, or
-- (at your option) any later version.
--
-- This program is distributed in the hope that it will be useful,
-- but WITHOUT ANY WARRANTY; without even the implied warranty of
-- MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
-- GNU General Public License for more details.
--
-- You should have received a copy of the GNU General Public License
-- along with this program. If not, see <http://www.gnu.org/licenses/>.
--
-- Comments, questions and criticisms can be sent to: sean@conman.org
--
-- ********************************************************************
-- Style: Lua 5.1
function do_dump(fpin,fpout)
local offset = 0
while true do
local line = fpin:read(16)
if line == nil then return end
fpout:write(
string.format("%08X: ",offset),
line:gsub(".",function(c) return string.format("%02X ",c:byte()) end),
string.rep(" ",3 * (16 - line:len())),
line:gsub("%c","."),
"\n"
)
offset = offset + 16
end
end
-- **********************************************************************
if #arg == 0 then
print("-----stdin-----")
do_dump(io.stdin,io.stdout)
else
for i = 1 , #arg do
local f = io.open(arg[1],"r")
io.stdout:write("-----",arg[1],"-----","\n")
do_dump(f,io.stdout)
f:close()
end
end
os.exit(0)
What I'm noticing (besides my text editor's horrible attempts at syntax highlighting in this entry) is that the non-C versions are quite a bit shorter than the C versions. I'm sure part of that reason is the high level of abstraction obtained by not using C. For instance, in this version, the code to dump the data is easily half the length of the shortest C version, thanks to the clever string.gsub() routine in Lua.
