A terrible function - or why I suck at programming.
18/1/2016
Now, I don't claim to be good at programming, in fact I know I'm not. I have been self-taught, there was no such thing as a programming class or course at my school or surrounding area, which sucked.
But today something different happened.
Today I found myself writing a function for my RGB controller project. I had decided to add a 'presets' feature to my project, allowing one to create RGB values they enjoy and save them to file for later use. This idea was great, so I began.
Twenty or so minutes later I was done. Done, yet highly disappointed.
Here is my controller now with the presets feature added. It is pretty useful.
However, the point of this post is not to display new features, instead it is to come out about the shame I feel for have written a particular function that is ugly, dangerous and messy.
The function in question is displayed below and is one that is used to read the presets file that contain information to be displayed in the application.
void MainWindow::readPresets() // read presets from file and display them
{
DebugLog("Reading presets from file");
// read file if it exists, display on screen
QFile file("/home/daniel_j/presets.cfg"); // change at some point!
if (file.exists()) {
file.open(QIODevice::ReadOnly | QIODevice::Text);
QTextStream in(&file);
while(!in.atEnd())
{
QString line = in.readLine();
QStringList presetName;
if (line.contains(":"))
{
presetName = line.split(":");
ui->presetList->addItem(presetName[0] + "-" + presetName[1]);
} else {
DebugLog("Error parsing line: " + line);
}
}
} else {
DebugLog("Presets file does not exist");
}
}
There are many issues, both dangerous and cosmetic in this function that I'd like to point out. The first, and most dangerous is my use of line.split() and line.contains().
To put it simply, at the time I was facing "index out of range" errors when attempting to split the line retrieved from the presets file. So, the solution, I thought was simple. Check that the line contains the character I use as the character I will split later in the function, and it works. Great! But no, not at all. Later in this function I use the split function to split the line into two and store it in a 'QStringList'. Once again, it all looks like it is going to work, and it does.The issue arises later in a function that sends the RGB value to my Arduino, at this point, the program would crash and close fatally. The issue is only occurs when a user manually edits the presets file and finishes the line with the character I use to split, ':'.
The solution that I need to, and will implement is proper line checking, instead of simple contains() checks.
The final issue I will touch upon (this post is already too long) is that of my use of QFile, specifically the file location I use.
The line in question is 'QFile file("/home/daniel_j/presets.cfg"); // change at some point!'.
Ahem, let me clear my throat, NEVER HARD CODE FILE PATHS THAT ARE NOT UNIVERSAL.
The end of an era and the beginning of a new horizion
14/1/2016
The end one of my most loved services has come.
The image uploaded service I once ran has now been taken offline.
Nobody except myself ever really used it anyway, and due to some recent happenings, bigger and better things are coming.
The biggest of which is lending my services to the creator of the game 'War World Infinity'. I won't say much about the game or creator except that you can follow their progress via their official Twitter account https://twitter.com/WarWorldInf
The game revolves around an interesting concept and I can't wait for it to become a working reality.
I am also now hosting a TeamSpeak server for a fellow CS:GO player, you can contact him via his Steam account (http://steamcommunity.com/id/Creeper_Corp500) or via TeamSpeak at danieljon.es.
If you're interested in getting a TeamSpeak server hosted for yourself, just ask! I'll be glad to provide you with one; providing I know who you are of course.
The third project is a potential upcoming project that revolves around the service that has retired today, keep up-to date here to find out more ;)
Don't worry, I will for sure keep on posting here weekly, unless I don't, in which case I don't.
My online identity and why being a nice guy screws you over
11/1/2016
Unlike many of you (or at least I presume) I've been known online by many 'handles' used to hide my real identity. No, I'm not referring to Mr. Anonymous on 4chan, instead a unique name that people can identify you with online. Lately however I've thrown the idea of anonymity out of the window and instead have been using the name 'daniel_j'.
You may or may not know me in real life, (if you do, sorry) but I tend to personally stick to a simple rule: Be as nice as I can possibly be and give anything I can to make others happy. Some may view this as 'buying' respect from people; well it is, that is true. What more can be said? Respect isn't something that comes free, it always has a price. Whether the price is weeks, months and years of time speaking and chatting with certain people online, getting to know each other greatly, or simply providing a service hosted on your own hardware/servers, it isn't cheap and it can heavily affect ones attitude towards you as a person - either positive or negative.
An inherit flaw to my master plan of utter bliss is that sometimes I just can't provide what is needed to either gain or prolong the respect once had and treasured. I don't like that - I can't handle the idea of not being able to provide something to you.
But that is crazy. Who are you to ask for something from me when I'm already providing you with something that is costing me. But, then again why am I happily providing you with a service. I met you randomly and felt bad due to your current service situation. Why am I not just putting you on my blacklist of people and carrying on. Why am I even typing this out, is it because I can't confront you again? Don't worry, I'm not removing your service, I enjoy it actually.
I'm a nice guy right, someone will one day show such niceness to me, right?
The solution isn't being an asshole, right?
If you're reading this - and you know who you are, I don't hate you, and I'm certainly not ignoring you, I just can't say no.
IRC Bot made in both Python and Java
7/1/2016
I help maintain and moderate (when it was relevant, now we just have fun) an IRC channel dedicated to user support for the game BeamNG.drive (www.beamng.com) located on the IRC server irc.beamng.com #BeamNG. If you have ever done any form of tech-support you know that the questions you receive are repetitive, very repetitive, and I for one, could only repeat myself so many times before I just had to come up with something easier.
An IRC bot was a great idea - there are literally thousands online and opensource - the most favourable being EggDrop. I however have integrity and cannot simply use such a thing to make my life easier. Instead, I opted to make one, well multiple, for myself.
Both of my final copies can be found here: https://github.com/daniel-Jones/BeamBot
One is programmed in Python, while the other in Java.
Both bots work in the same simple manner:
- Bot is started via a console
- It creates a socket connection to the IRC server, it then joins your selected channel and idles
- The bot runs enters a loop that both checks for messages, logs the channel, checks for certain key word commands and replies to PING/PONG
- When the bot finds a line that begins with '?' a file full of commands is opened and parsed one by one to find valid commands and provide a channel response
The bots are pretty simple, but has saved myself and others plenty of time.
My IRC nick is daniel_j I can be found at the following locations, why not say hi:
- irc.danieljon.es #fun
- irc.beamng.com #beamng, #offtopic, #speedsims
Analysing and explaining my source code.
26/12/2015
Let's face it, my blog is stale - rarely new content, and whenever there is new content it is often short and boring.
I've decided to try something different, I'm going to being walking you through snippets of my code, explaining what I'm doing and my though process, just for fun.
I'm going to start today with my latest mini project, the number storage program.
The first section of my value recording program is simple.
I first include some C standard libraries that I need:
stdio.h - used for standard IO such as printf etc
string.h - used for comparing strings
time.h - pretty simple, I use this library to determine the systems time
I then proceed to define two functions that I use later on, this is to ensure that the C compiler knows the functions exists - compilers are dumb.
/* database like program to record values */
#include stdio.h
#include string.h
#include time.h
/* functions */
void addRecord(char* value);
void readRecord();
Next up, just like every other C program in existence I define a main function and add code inside of it. The main function in any program is the first place any compiler looks for code - without the presence of this function your program WILL NOT compile.
To attempt to keep things slightly less complicated I shall post the source first and then explain it.
int main(int argc, char* argv[])
{
if (argc < 2)
{
printf("Utility for recording and monitoring values\n");
printf("This utility requires arguments.\nusage: %s -l [list records] -i [insert record]\n", argv[0]);
return 0;
}
int i;
for (i = 1; i < argc; i++)
{
if (strcmp("-l", argv[i]) == 0)
{
readRecord();
break;
}
if (strcmp("-i", argv[i]) == 0)
{
addRecord(argv[i+1]);
break;
}
}
return 0;
}
Now, this is about the time those of whom don't know at least a little programming should leave - I'm not here to teach you how to program, just to explain what I do!
I define the main function as an int - as you should know this is due to passing the OS an exit code upon completion. I also use the common "int argc, char* argv" to obtain CLI arguments as this is, of course a CLI only program.
I follow the definition by checking for arguments, if this program does not receive at least one argument I print to the screen usage instruction and end the program.
Once it has been confirmed that at least one argument has been passed I check them incrementally for specific key triggers - -l and -i. If none of these are found, the program ends silently - I could have told the user they didn't input a correct argument, but why bother.
If the correct arguments are found, I call the relating function (the same ones we defined earlier) and let them take over - after passing the correct values of course, which in -i's case is anything AFTER the -i (-i was to INSERT, -l was to LIST).
Once the functions are complete, we break out of the for loop and end the program - our job is done.
The final parts to be explained are the two functions we use.
void addRecord(char* value)
{
printf("Adding record: %s\n", value);
/* before we open our file, we want to get our date and time setup which we will also write */
time_t rawtime;
struct tm *timeinfo;
time(&rawtime);
timeinfo = localtime(&rawtime);
/* open file for writing */
FILE *fp;
fp = fopen("values", "a"); /* a to append, not w - would overwrite */
if (fp == NULL)
{
printf("Can't open the file for writing.");
}
else /* file open, write data */
{
fprintf(fp, "%s - %s\n", asctime(timeinfo), value);
fclose(fp);
}
}
Oh my, if you are new to programming close your eyes and run, this looks scary.
This function labelled "addRecord" does just that, it adds a record to the file we are using to store our data.
Now, I have to be honest, this is a simple ass way of storing values. I use no database, I just take whatever a user enters and append it to the end of a file - lazy, yes, but very convenient as I don't expect anyone to actually use this script, except myself.
I begin by informing the user of what record is being appended to the file. I follow it by some nice copy-pasta code for retrieving and converting the time and date to a human readable format that will also be appended to file.
At this point we are ready to append our data to file, so I generically create a FILE pointer and fopen the file we are using to store data. I open it with 'a' access to allow the data to be appended - using 'w' for write mode WILL OVERWRITE the file, we don't want this.
I then check to see if the file was opened successfully, if not I inform the user and the function ends there. If it was however opened correctly, I fprintf the data into the file we opened and then, of course then close it. The function then ends. Also note how I never delete the fp pointer, sue me.
The next function is awfully similar and just reads and displays the entire file to the screen.
void readRecord()
{
/* open file for reading */
FILE *fp;
fp = fopen("values", "r");
if (fp == NULL)
{
printf("Can't open the file for reading.\n");
}
else /* file open, read data */
{
char buff[1000];
while (fgets(buff, 1000, fp) != NULL)
printf("%s", buff);
fclose(fp);
}
}
I use fgets to retrieve the files data into a buffer and then print it, etc
Awfully simple, yet quite nifty and useful.
Should I bother doing more of these? Probably not.
simple C CLI program for adding and monitoring values
21/12/2015
I had a personal reason for needing to insert, store and monitor specific values - I could have just used a text document or piece of paper - but that is boring, who likes boring?
The program in action is displayed below.
The program allows only 2 arguments: -l (lists the values stored) and -i (insert values), everything else is ignored.
To compile and run the program simply enter in any Linux programming environment: gcc main.c -o valueStorage;./valueStorage
The program will compile and present you with an output describing your options.
The source code is located here for anyone to use: http://pastebin.com/027YH4Qi
As always, you can contact me via my email: admin@danieljon.es or via irc: danieljon.es:9090/?channels=#fun
(if you try to use the IRC server use a realistic name that identifies yourself, if not you will be kicked from #fun)
Been on Windows playing Fallout 4 - ashamed.
1/12/2015
But, i'm now back home doing what I love.
A new theme face lift, fancy background images and home security camera setup. Perfect.
Current work space - split over 2 1920*1080 monitors.
I'm currently working on my RGB lighting program - more precisely, I'm working on the micro-controller side of things - fun!
So much for """"daily"""" media/posts.
You can always find me on my IRC server - http://danieljon.es:9090/?channels=#fun - I kick anyone that doesn't identify themselves.
Or, contact me via Email at: admin@danieljon.es
Game engines and OpenGL
6/10/2015
Lately I've been teaching myself OpenGL in C using GLUT, literally as low level and annoying as you can get.
Just today I've been playing with an engine known as 'Irrlicht'. It is an OpenGL C++ API for OpenGL.
At the moment i'm just simply loading meshes and maps from Quake, I hope soon to get a shooting game of sorts going, but that is quite a while away.
You can download a video of my current progress here
Langton's Ant
20/9/2015
Inspired by https://www.youtube.com/watch?v=NWBToaXK5T0 I've decided to embark on creating my own version of this simulation using Qt/C++.
Yet another boring weekend.
Woo, I have a grid drawn, amazing.
2d graphics suck.
Card hand generator
17/8/2015
When not flicking them i'm randomly generating them, because why not.
It is written in C and is able to be compiled on any UNIX/Windows environment.
example use:
./CardsGrid hand 5
this generates a completely random hand of 5 cards. (seeded with the current time)
the code for this mini-project can be found here http://pastebin.com/1KyJBEB6
