drop function if exists luhn;
drop function if exists luhn_check;

delimiter //

-- Function that calculates a Luhn (mod 10) check digit from a numeric string.
-- The behavior is undefined if the string contains anything else than digits.
-- Assumes that the string does not have a check digit added yet, so it starts
-- with a weight of 2 at the last digit.
create function luhn(p_number varchar(31))
    returns char(1)
    sql security invoker
begin
    declare i, mysum, r, weight int;

    set weight = 2;
    set mysum = 0;
    set i = length(p_number);

    while i > 0 do
        set r = substring(p_number, i, 1) * weight;
        set mysum = mysum + if(r > 9, r - 9, r);
        set i = i - 1;
        set weight = 3 - weight;
    end while;

    return (10 - mysum % 10) % 10;
end //

-- Check if a numeric string has a valid check digit. Does this by cutting off
-- the last digit, recalculating the Luhn check digit, and comparing the strings.
create function luhn_check(p_number varchar(32))
    returns boolean
    sql security invoker
begin
    declare luhn_number varchar(32);

    set luhn_number = substring(p_number, 1, length(p_number) - 1);
    set luhn_number = concat(luhn_number, luhn(luhn_number));

    return luhn_number = p_number;
end //

delimiter ;

I wrote this small script for Windows to compress movies (avi, mkv etc) down to cell phone format. The encoding isn’t great, but the average two-hour movie compresses down to just about ~100 MB, which is really nice. Works fine on Nokia N85. Edit to suit your needs. It relies on ffmpeg, which you can find Windows binary downloads for here and there. Google for it, kid, google for it!

Oh, it also requires cygwin, for the perl interpreter. (Or ActivePerl, I suppose.)

ff-m4v.cmd:

@echo off
set CYGWIN=nodosfilewarning
for %%F in (%*) do (
    echo.
    echo ######## %%F #########
    echo.
    perl %~dpn0.pl %%F
)

ff-m4v.pl:

$in = shift;
$data = `ffmpeg -i '$in' 2>&1`;

$out = $in;
$out =~ s/\.[A-Za-z0-9]+$/\.m4v/;

($x, $y) = $data =~ /Video:.*?(\d+)x(\d+)/i;
$dx = 320 / $x;
$dy = 240 / $y;
$d = $dx < $dy ? $dx : $dy;

$dim = int($d * $x) . 'x' . int($d * $y);

$opt = "ffmpeg -i '$in' -f mp4 -vcodec mpeg4 -b 80000 -r 12 -acodec aac -ar 16000 -ab 48000 -ac 1 -threads 2 -y -s $dim '$out'";
print "$opt\n";
system($opt);

The parameters evaluate to mpeg4 encoding, 80 kbit/s bitrate for video, 12 frames per second; AAC encoding with 48 kbit/s bitrate, mono sound. It compresses the movie down to a maximum of 320x240 pixels, but preserves aspect ratio (effectively becoming 320x196, 320x160 or whatever). If you want to use 2-pass encoding, it's easy; just repeat the system($opt) call with "-pass 1" and "-pass 2" parameters.

Put both in the same folder, make sure ffmpeg.exe is in the system path, and run "ff-m4v *.avi".

I usually sign on to work by starting at least four different programs: Microsoft Lync, Miranda, a SIP telephone, and a little break clock. I used to have a Python script for it, but I thought that installing ActivePython on a Windows machine just to start four programs is a bit of an overkill. So I wrote a CMD file instead. It’s really amazing what you can beat the old CMD interpreter into doing.

startToday.cmd:

@echo off

tasklist /nh > __tasklist.txt

for /f "delims=" %%F in (startToday.files) do (
    findstr /b /i "%%~nxF" __tasklist.txt > nul
    if errorlevel 1 (
        echo starting %%F
        start "" "%%F"
    )
)

del /q /f __tasklist.txt

startToday.files:

C:\Program Files\CounterPath\X-Lite\x-lite.exe
C:\Program Files\Miranda IM\miranda32.exe
C:\Program Files\Microsoft Lync\communicator.exe
C:\Home\stuff\software projects\BreakTime\BreakTime.exe

Voila!

A small batch file I wrote today, to back up MySQL databases, table by table.

So many times have I needed to restore only a specific table, and yet it’s so difficult to dig out the correct table from the whole database backup file (or even worse, server backup file).

This little file will store the whole database/server in individual files, and if you run it on a daily basis, will keep history in “backup.n” directories.

@echo off

rem Enable delayed expansion - otherwise the backup.n folder renaming won't work
setlocal enabledelayedexpansion

rem Change to the script's home folder
%~d0
cd %~p0

rem Rotate previous backup folders
if exist backup.9 rd /s /q backup.9
for /l %%i in (8 -1 1) do (
    set /a j=%%i + 1
    if exist backup.%%i move backup.%%i backup.!j! > nul
)
if exist backup move backup backup.1 > nul

md backup

rem Change these to reflect your MySQL connection parameters
set OPT=-ubackup -pbackup -hlocalhost

rem List all the databases and process them
mysql %OPT% -e"show databases" --skip-column-names -B | findstr /v "information_schema" > _db.txt
for /f %%d in (_db.txt) do call :backupdb %%d

rem Clean up, clean up, everybody wants to clean up
del /f /q _dbt.txt
del /f /q _db.txt

dir backup

goto :eof

:backupdb
    rem List the tables in the current database
    echo %1
    mysql %OPT% -e"show tables" --skip-column-names -B %1 > _dbt.txt
    md backup\work

    rem Dump each table into an SQL file
    echo  - dumping data
    for /f %%t in (_dbt.txt) do mysqldump --opt %OPT% -rbackup\work\%%t.sql %1 %%t

    rem Compress them with 7-zip into a single zip file
    echo  - compressing
    cd backup\work
    ..\..\7z -y a ..\%1.zip * > nul

    rem Clean up
    cd ..
    rd /s /q work
    cd ..
    echo.

    goto :eof

Download 7-zip, extract 7z.exe and 7z.dll and put in the same folder as the “backup.cmd” file above, and you should be good to go. Change the -u and -p parameters in the “set OPT” statement to reflect the login settings for your database server.

/**
 *  NF_Persistence
 *
 *  Agent Smith: "Why, Mr. Anderson, why? Why do you persist?"
 *  Neo:         "Because I choose to."
 *
 *  PHP Version 5
 *
 *  @category   NiftyFramework
 *  @package    NiftyFramework
 *  @subpackage Database
 *  @author     Mats Gefvert

 *  @license    http://www.sun.com/cddl/ Common Development and Distribution License
 */

class NF_PersistenceRelationMap
{
    ....

I make myself laugh sometimes. Is that a good sign? :)