Corrected following point in my article Understanding and implementing CRC article:
In the reciprocal CRC model, the final XOR value must not be reflected, contrary to my previous statement. Note that in the source code, this was already correctly implemented.
Enhanced my online CRC calculator by adding support for 64 bit CRC and binary string as input data!
Added an online ELF viewer to investigate ELF files (ELF header, section header table, program header table, symbol tables and note tables) in a browser - Check it directly out here!
The source code of implementation in Typescript is of course also available here.
Removed my guestbook as the provider went down. Let's see if I'll add a new one ;-).
Added a tool: ELF viewer console.
Simple console application coded in C# to read the most important information from 32/64 bit ELF files. Supports ELF header, section header table, program header table, symbol tables and note table.
Check it out here!
Updated the CRC implementation in C# to support 64bit CRC calculation - check it out here.
Added a demo how to multiply two unsigned 32 bit values using only 16bit multiplications, shifts and casts in C here.
Added an visualization of the two-dimensional cross and dot product in Typescript here.
Added an visualization and description on how to calculate the area of a simple polygon in Typescript here.
Added an mathematical article about the derivation of the two-dimensional dot product and its geometric interpretation.
Check out the article here: Derivation of the dot product in R2.
Added an article about implementing a fixed point number class and the main arithmetic operations.
Understanding and implementing CRC article
Added a new article about generating all possible permutations of a given set. Presents three different algorithms with examples. Implementation with source code of eight different algorithms in total available for download.
Check it out here!
Added a little demo how to use the TaskbarList3 interface using plain Windows API in C/C++ to set the progress info on the taskbar, handle taskbar buttons or set an overlay info. This should serve as a good starting point for everybody how wants to modify the taskbar of its application this way.
Windows TaskbarProgress Example
Another small issue found by an attentive visitor: In the article 'Software Rasterization Algorithms for Filling Triangles' inside the function fillTopFlatTriangle(), the new scanline was calculated after the call to draw it - this is not perfectly correct for very narrow triangles (the order was correct in fillBottomFlatTriangle() though). Fixed in the article and in the source code archive.
In several cases, a zero inside the result CRC is missing, thus e.g. the printed result was 0xC6FF2F8 instead of the correct one 0xC6FF02F8. Note that the Silverlight variant is not affected!
Root cause was a bug in the conversion from the numerical CRC value to the printed result string. This is fixed with this update - sorry for any inconvenience caused!
Added a new article about understanding and implementing Base64 encoding and decoding.
Check it out here!
Fixed a bug in my recursive parser algorithm reported by a user. The handling of plus and minus operator had an incorrect order. Updated the article and also the linked source code.
Added licensing information to my site. All content of this site is now licensed under the MIT license.
Still I'm always interested about you - the visitors. So if you (re)use content of my web site -> feel free to drop me a line about who you are and for which project you use it. I would be pleased.
Updated the article about parsing algorithms for mathematical expressions. Hopefully the chapter about the creation of a syntax tree directly from the normal infix expression is more clear now. Check it out here!
Also the guestbook is fixed and works again - so leave some comments!.
Updated my Understanding CRC article with a new chapter about basic CRC math and common questions -> Read it now here!
Well, actually I started to continue the development of SunPEView (I have so many ideas!). However, I noticed that the completion of the next version would would take forever because I have too less time.So after some hours I decided to stop...
... and to release the current development state as version 0.7.1.0
... and to release the complete source code as free download! (Be aware that it's not cleaned up but just zipped as it is ;-)
Hopefully some of you find it interesting and maybe it extends your knowledge. Drop my a line if you reuse parts of it! Maybe in future I will come back to it and proceed its development again...
-> Get the source code here!
New article about understanding and implementing various CRC (Cyclic Redundancy Check) algorithms. Explains the basic idea of CRC and evolves step by step different algorithms and discusses their implementations. You think that's awesome?
-> Read it now here!
Additionally, an online CRC calculator is available as Silverlight application: Check it out here!
New article about three different (self-developed) algorithms to calculate the difference of dates in days. Read it now here!
Additionally, try them out online as Silverlight application to get the difference of dates: Check it out here!
After having tried out Perl, I checked out something new again - this time Silverlight! My first impression is quite good: I can use C# as language, there is a pretty good development environment for free (Microsoft Visual Web Developer Express), the GUI can easily be created using a visual designer and the applications run easily in a browser - without security issues (at least for now) compared to Java applets. So if you're interested, give it a try - it's worth to check it out.
My first silverlight application is a demonstration of my implementations of various (perfect) maze generation algorithms: Depth First Search (Recursive and Iterative), Hunt and Kill as well as Eller's algorithm. The size of the maze and well the starting cell is configurable. Also the mazes are not generated instantly but there is also a step-by-step generation possible to visualize the working of the algorithms. Curious?
Check out my Maze Generator in Sliverlight here!
Update 2014-09-17: Moved silverlight to its own site.
Added a new fancy tool called WindowsUpTimes. It's a little console application which shows the start and shutdown times of Windows. Technically it uses the EventLog API to access the system event log to extract this information. Actually no big deal, but I just needed such a tool for myself and just wanted to share it :)
Check it out here!
I have done my first steps in ... Perl!
As first exercise I ported 'My Simple Playlist Generator' written in C# to a Perl commandline tool. Interested? Look here: Look here.
Released version 0.7.0.0 of my PE Viewer tool SunPEView!
Extended support of resource directory (e.g. show save bitmaps, cursors and icons to file, but also many more); support for Base Relocations, Exception and TLS directory. Fixed some bugs, better error handling and many more...
Look here: SunPEView.
Added a new article (with Java applet and source) about the relation of a given point to a given line in the two-dimension case. It contains algorithms how to detect if the point is on the given line, if it's one the line segment or if the projected point onto the line is on the line segment. Pretty interesting, isn't it?
Check it out: Point on Line algorithm article.
I wish everyone a happy new year 2014!
Released the first (alpha!) version of my new PE Viewer tool SunPEView! Currently it's only version 0.6.0 and unstable, but is more or less working. Try it out and stay tuned for updates! Look here: SunPEView.
Furthermore, I have noticed that all of my applets were not be able to be executed in newer FireFox versions due to more stright security settings. I have now signed all applets so that you get a warning during loading, but at least you can exeucte them at all. Note that I did not update any zip files, so when downloading the archives for offline use, they will be most probably not being exeutable in Firefox, unless you lower your Java settings in the Java console.
Fixed two typos in articles:
In the rotation derivation article, changed x-z-plane to x-y-plane in the last chapter. Second, the wrong derivation x4 = x1 + ((y2 - y1) / (y3 - y1)) * (x3 - y1) in the triangle rasterization article was corrected to x4 = x1 + ((y2 - y1) / (y3 - y1)) * (x3 - x1). Thanks to the two reporters for pointing them out!
After many years I have written a new RCE article... Yes, you read right, no joke! I felt it's time to dive into PE files again - because reversing is fun!
It's about to insert a messagebox at the entrypoint of a .NET PE file the hard way - using a hex editor. (Sounds familar to you? ... it's actually the same as the original 2002 tutorial for standard PE files, just for a .NET file).
On the way to our goal some parts of the .NET file structure are discussed and analyzed....
Sounds interesting -> check it out now!
Updated my HeaderIncludeTool to version 1.02 with some minor enhancements and bug fixes ;-) Check it here!
Added a new article along with an applet (and source code) about the hough transform to detect lines in image.
Check it here!
Enjoy it and a happy new year!
[Actually the package was released on 28th, but updated today. So if you already got the package yesterday, please download it again - a small bug was fixed.]
Well finally I updated my website layout! Well, maybe you think now 'Hm looks the same as before, doesn't it?'
This is correct, also no additional content was added, but I have thought of internally cleaning up my site for some time and finally I have pushed myself to do it. Biggest change is probably the fact that I switched from a frame-based website to an CSS-style website! Also the structure was tighted up, dead links removed and so on... Be aware of the fact that older links might not work anymore because the directory structure was also improved.
Hope you like the renovation of my site and stay tuned for updates!
Just improved slightly my HeaderIncludeTool (version 1.01) - check it out!
The article and applet on how to rasterize a triangle is finally finished - check it out!
Added a little C# tool 'HeaderIncludeTool'.
It parses C source files in order to build a header include dependeny tree. Might be useful if you want to find a cycle in your include hierarchy. Can run as wizard-like GUI application as well as console app. Of course, source is available...
Curious? Check it out here!
Finally I finished the article about testing if a point is inside a given triangle featuring two different algorithms: One algorithm uses the so-called perp-Dot-Product to check the point againt the three edges of the triangle. The second one uses barycentric coordinates for triangle representation and evaluates the final equations using Cramer's Rule.
Check out article, applet and source!
I wish all my visitors Merry Christmans and a Happy New Year!
Added a short article about the rotation of a point around the x-, y- and z-axis. Check it out here! Enjoy!
After my beloved Nokia 3200 finally broke down after 7 years of permanent use (having only the second battery which has been still been in perfect quality), I had to get a new one and came up with a Nokia C2-01. Yes it's not a smartphone (of whcih I am NOT a fan of), but a simple-to-use old-school mobile phone and I am completely satisfied with it.
Nevertheless, I use this of an occasion to continue with J2ME coding. I remembered that I had a lot of fun coding the three games for my phone back in 2k4. The C2-01 has more processing power and also supports a newer MIDP/CDLC version so I decided to code even better games. I know it will take some of my limited time, but hey.... it's fun!
As first project (to set up my development environment and refresh my knowledge about midlets), I just hacked a small midlet to read the properties (like size of the screen, supported MIDP version etc.) of my mobile phone. Well, I think it's quite useful so.... here it is!
First I fixed some bugs in my SearchStr tool (which I personally use quite often) and also improved the commandline arguments. Go and get version 1.1!
Second the final version of my StoneBreak game is released. More levels, more special effects, less bugs, designed for different resolutions, a level editor for offline gaming and ... for everything the source code is available! Awesome? Right! Check it out now!
Ops, the durations without any updates grow and grow... Sorry for that! You know, spare time is short and valuable. But finally I started a new game that I always wanted to code myself - a little breakout clone which I called Stonebreak. I chose Java as language to make use of the Graphics2D class - and although it's not finished yet, it looks quite nice and makes fun. Go and check out the first version yourself!
After some time I was really motivated and had fun to code a
cool graphics algorithm again. Well, the choice was made and the
result is my implementation of the famous Bresenham algorithm for
rasterising lines, circles and ellipses. I hope you like it and
learn something from the applet and my code - so go check it out.
Moreover, I did some little changes (e.g. deleted some old links) and I noticed that nobody leaves a message in my guestbook - so if you like my site, articles and/or sources, drop me some lines. I would really like it. Keep on coding!
By the way, this reminds me of something: in the last time several visitors pointed me to several broken links on my site - thanks a lot to those and I am always pleased to get informed about non-working files on my site!
Finally I finished a piece of code and the belonging article at
which I have worked really some time. At the time I
developed my Online
Calculator I though about other approaches how to parse and
evaluate mathematical expressions. While I stuck at that time at
the recursive (and easiest) approach, I have implemented now other
algorithms. The result is the article describing the a) recursive
approach b) postfix and stack approach and finally c) syntax tree
creation from infix notation. Have fun while reading!
Hi folks, today I publish a little commandline (which I coded
for myself) to search for strings in files or directories. Turned
out to be quite handy sometimes. Of course the C source is also
available. Check it
Coded my first crackme (finally). Nothing special - quite easy,
but I think some beginners will definitely like it. Check it out
First of all, I fixed a lot of broken links. Many zip files were stored on another server (a free one) than the actual site, but this one was closed down - now everything should work now.
Second, a guy named Gergely found a bug in my polygon filling
implementation - look at this screenshot. The problem were horizontal
lines - in that case the endpoints were not correctly handled.
Fixed that problem - thanks for the hint.
Finally I managed to update my study site with information about my diploma
thesis... although I finished my thesis nearly one and a half year
ago! Shame on me! Good things come to those who wait
Probably some of you have heard about the so-called Birthday
Paradox or Birthday Problem. I personally find it quite interesting
(with a surprising result) and decided to summarize my own notes
and thoughts. I do not only present the probablity calculation, but
also tried to give some logical notes. In fact, it is quite
difficult to explain this problem to others cause there is very
similar question (with a different solution) with which it is easy
to get mixed up.
So I hope you like it - click here to get to the Birthday Paradox Article.
So folks, I found some time for coding and implemented the 14-15 Puzzle as a Java applet. Of course, you can play it online yourself, but I think more interesting is the automatic solver which solves a puzzle instance in front of your eyes step-by-step! Moreover, you can generate random puzzles using two different algortihms and check if they are solvable or not. Curiuos? Check it out here including my notes about the theory of the 14-15 puzzle.
Mr.reCoder advised me of some really nasty mistake. The
readme.txt file I have been including in every download archive on
my site for several years - well it contains a nasty spelling error
*shame on me* : Of course, the URL to my site is www.sunshine2k.de
and NOT www.sunhine2k.de (not the missing 's')! I am too lazy to
correct this in every zip archive, but I have corrected it for
future releases. Please keep that in mind or better - bookmark my
Andreas Böhm found a bug in my polygon convexity source code which classified a concave polygon as convex. Below is a screenshot with the wrong behaviour and the fixed version:
I have corrected the pseudocode in my article about polygon
convexity and also updated the applet source about polygon filling.
Thanks for the hint and also for providing me with the
So, finally I release now my first applet written in JavaFX
ever. It allows to calculate resistor/electronic color codes to
resistance values and the other way round. In fact it took me quite
long to dive into JavaFX and to write the user interface - that's
why the 'GUI' is written in JavaFX, but the calculation logic is
coded as normal Java classes. I think the result is quite nice so
check out the applet including source here in the Java
For personal needs and interest, I delved into the structure of
bootsectors of hard and USB drives. As I was also motivated to code
something in C again, the result is a simple tool providing the
most important information of a FAT/FAT32/NTFS bootsector and also
allowing the dump the bootsector to file for further investigation
with a hexeditor. Maybe it's a good starting point for some
disk-info utility. Check it out here.
I added a little commandline tool that allows you to change to
display settings by giving commandline arguments. That allows you
for example to change the display mode from a .bat file. It is kept
quite simple as it was coded solely for my personal needs, but
maybe someone else needs it - or wants to extend it. It can be
I 'hacked' this tiny app very quickly for personal needs. I
wanted my music files sorted after file creation / modification
date and none of the media players I use provided this
functionality. This tool just parses a directory (with/without
subdirectories) for music files and writes them to a *.m3u file
(ready to be loaded with e.g. Winamp) sorted after modification
date (from oldest to newest). That's it - maybe you are searching
for exactly this tool. If not, as the source is easy, feel free to
take it as a starting point to generate your own playlists by
implementing your own sorting criterias. <Look here>
Added a new part to my polygon algorithm serie - the implementation of Kong's Algorithm for polygon triangulation. Again, you find there a short explanation of this algorithm, the applet for playing around and of course the corresponding source code. Check it out here!
Thanks go to Mr.reCoder for correcting a bug in my Self-deleting Excecutable in
MASM. Now it works also with long pathnames including spaces by
using the GetShortPathName function
which was unknown to me till now :-)
Finally I release the complete source of my Online
Calculator as a little present... Merry Christmas to all of
you! I hope you find the source interesting, especially the
recursive parsing process and my autocomplete feature. If you like
it, use it or parts of it, please give my some credits and link to
Released my 'AviToYuv'
tool which converts avi files to planar 4:2:0 YUV files using the
Video for Windows API. I coded it during my diploma thesis for
having more videos to test my modified H.264 encoder - the standard
sequences were too boring...
I fixed two small parsing bugs in my Online
Calculator - I hope it works now always correct
Moreover, I added additionally an autocomplete feature I coded some time ago just for fun.
As you can see, I changed my site layout a bit - I hope
everything is now clearly arranged but I'm still not completely
happy. More modifications to come, I have also coded already two
useful tools concerning .yuv files which need just a some comments
and bug-fixing before releasing - but time is valuable resource for
the time being because my diploma thesis has of course priority.
But stay tuned!
I finished coding my online calculator - finally :-) If you also have never a hand calculator at your fingertips when you need one and are tired using the standard Win/Linux calculators for evaluating mathematical expressions then be sure to check it out:
Finally, the study thesis paper about my
HyperTransport-Monitoring-Core is available for download in the
Long time I did not solve any crackme - no time & no
interest. But while looking around on crackmes.de I found a
special, 'different' crackme. No .exe but a .gadget file - a
crackme in form of a Windows Vista Sidebar Gadget. Find out more
about it <here>.
While looking around my site, I found a bug in my Cohen-Sutherland-Applet which resulted in an endless loop. Fixed it - there was just missing a simple 'else'.
I came across Welzl's algorithm for calculating a smallest
enclosing disk in expected linear execution time while I learned
for my oral exam and found it quite interesting. Although it's
quite simple, I was fascinated why this really works and so I did
my own implementation of it which was harder than expected.
So a little site update...
* The coding section has now a table of contents.
* Updates on my study page concerning my study thesis.
* Removed dead links in the links section.
A few days ago I started learning for my last oral exam - this
time about computer graphics. Again I have to deal with B?zier
curves and so I came across the de Casteljau Algorithm again which
uses the recursive relation of Bernstein polynomials which in fact
bases on Pascal's rule. None of my books contains the proof of this
formula so I did it myself and decided to publish it here on my
site. It's really short and simple but perhaps somebody is
-> Articles -> Math & Theory or directly <here>
I did not code for month - damn I have no time! Too much to do for my studies and real life has priority in my spare time. But somewhen in future this hopefully will change and there'll be more updates :-)
This site is part of Sunshine's Homepage