Tag Archives: development

GZip with ZLib

In an effort to use zlib in VBA, I had to first learn to use it.  I’m looking to gunzip the XFDL files to use the data as an MS  Office plugin.  In tinkering with zlib’s GZip functions, I found them to be very much like normal file handling in C.  Here’s a link to the official zlib reference manual, GZip is the tenth section.  So, to test it, I made a “micro-gunzip” which does work well.  When compiling, don’t forget to link to libz.a using gcc -o out -i in.c -lz.   Other than that, enjoy!  The basics are covered in the comments.

#include <stdio.h>
#include <zlib.h>
/* gcc filename.c -o outname -lz */

int main(int argc, char *argv[]) {
	// variables
	gzFile gFile;           // gzip file object
	FILE *pFile;            // out file object
	char *filen = argv[1];  // get the name of the file
	char buffer[100];       // buffer for reading

	// open files
	gFile = gzopen(filen, "rb");        // same as file
	pFile = fopen("example.out","wb");
	if(pFile == NULL || gFile == NULL)
		perror("Error opening file");
	else {
	    // write
		while(!gzeof(gFile)) {
			gzgets(gFile,buffer,100);   // file object first
			fputs(buffer,pFile);        // write to plain tex
		// close
	return 0;

Fern Screensaver : Part 4

I’ve now completed the Fern Screensaver in Objective-C for the Mac!  Surprisingly, using Objective-C was not that far from C/C++.  In fact, much of my code could be pasted directly in.  That includes the variables, math functions, etc.  Also, Mac has done a good job of documenting it’s libraries so using the NSObjects was not that difficult between Google and a quick reference search along with the example screensaver code.  I’m going to hit a few key differences and then post the entire file I edited.  XCode does the templating pretty well.

First, all the variables are at the top of the code so they don’t change as the program advances frames.

float mat[4][7] = {

@implementation ZackScreenSaverView

Secondly, I had to use implement my NSObjects at the start of the -(void)animateOneFrame method.  The size = [self bounds].size; calls the screensize.  It’ll take some time to get used to the method calls in Objective-C!

- (void)animateOneFrame
	NSRect dot;
	NSSize size;
	NSColor *color;
	NSBezierPath *path;
	float red,green,blue,alpha;

	size = [self bounds].size;

The framework has some good methods for getting random floats, or any integer type!

	// random number
	p = SSRandomFloatBetween(0.0,1.0);

Finally, it took some new methods to draw my dots to the screen.

	// set dot
	dot = NSMakeRect(jx,jy,1.0,1.0);

	// make dot
	path = [NSBezierPath bezierPathWithRect:dot];

	// draw dot
	[path stroke];

Other than that, the rest is pretty much the same.  I encourage those more used to Objective-C and programming for Mac products to comment about the use of this code and correct any bad assumptions!  Here is the code in it’s entirety (note that I’ve taken out the redraw at this time)…

//  ZackScreenSaverView.m
//  ZackScreenSaver
//  Created by Zachary D. Skelton on 5/30/10.
//  Copyright (c) 2010, Skelton Networks. All rights reserved.

#import "ZackScreenSaverView.h"

float mat[4][7] = {
// constant sets
float xa = -5.5;
float xb = 6.5;
float ya = -0.5;
float yb = 10.5;
// x and y to be altered
float x = 0.0;
float y = 0.0;
// screen/image size
int ix = 512;
int iy = 512;
// floats for math fulction
float p = 0.0;
float x0 = 0;
float jx = 0;
float jy = 0;
// variables to control function
int i = 0;
int k = 1;
int end = 10000;

@implementation ZackScreenSaverView

- (id)initWithFrame:(NSRect)frame isPreview:(BOOL)isPreview
    self = [super initWithFrame:frame isPreview:isPreview];
    if (self) {
        [self setAnimationTimeInterval:1/30.0];
    return self;

- (void)startAnimation
    [super startAnimation];

- (void)stopAnimation
    [super stopAnimation];

- (void)drawRect:(NSRect)rect
    [super drawRect:rect];

- (void)animateOneFrame
	NSRect dot;
	NSSize size;
	NSColor *color;
	NSBezierPath *path;
	float red,green,blue,alpha;

	size = [self bounds].size;

	ix = size.width;
	iy = size.height;
	dot = NSMakeRect(ix/2,iy/2,1.0,1.0);

	red = 255.0;
	green = 255.0;
	blue = 255.0;
	alpha = 255.0;
	color = [NSColor colorWithCalibratedRed: red
									  green: green
									   blue: blue
									  alpha: alpha];

	[color set];

	// random number
	p = SSRandomFloatBetween(0.0,1.0);

	// find random i
	if(p <= mat[0][6])
		i = 0;
	else if(p <= (mat[0][6] + mat[1][6]))
		i = 1;
	else if(p <= (mat[0][6] + mat[1][6] + mat[2][6]))
		i = 2;
		i = 3;

	// super math function
	x0 = ((x*mat[i][0])+(y*mat[i][1])+mat[i][4]);
	y = (x*mat[i][2]+y*mat[i][3]+mat[i][5]);
	x = x0;
	jx = ((x-xa)/(xb-xa)*(ix-1));
	jy = (iy-1)-(y-ya)/(yb-ya)*iy-1;

	// set dot
	dot = NSMakeRect(jx,jy,1.0,1.0);

	// make dot
	path = [NSBezierPath bezierPathWithRect:dot];

	// draw dot
	[path stroke];

	if(k == end) {
		k = 0;
	} else
		k += 1;

- (BOOL)hasConfigureSheet
    return NO;

- (NSWindow*)configureSheet
    return nil;


Microsoft Access : XFDL Viewer – Introduction

I know, I said it yesterday that it is rare that I develop on Windows, but this is a long promised application.  In 2007, my unit administrator (in the U.S. Army Reserves) suggested code that would allow batch loading XFDL forms from MS Access.  Due to the scope of the Apps 4 The Army project, I was limited to using a web application.  Now that the project is submitted and done, I am free to do my original plan, which is code to do the same process in MS Access.

Starting this today, I realized how much I hate doing Visual Basic.  Particularly, VBA is very painful!!  It’s not that the language is bad but it just always feels bulky and pieced together to me.  It seems to lack the professionalism of C/C++ and the flow of Python.  But, I may be alone in that.

I have a question for my readers though. Would anyone have an interest in seeing this project on SourceForge?  The Apps 4 the Army project is no longer my intellectual right, but a desktop application, a MS Office Plugin, etc… that’s all good to make public.  So let me know, if I get readers saying we’d like to help; then I will happily move this project to SourceForge!

Fern Screensaver : Part 1

So my brother has asked me to help in making some iPhone/iPad applications.  Sounds like a great idea, I just need to get used to Objective-C.  If you already know C/C++, it’s not a huge leap to produce some iPhone code.  But I’m short of ideas to write and since most of the Mac is using Objective-C, I’ve decided practicing that language with something else, a screen saver!

I have done a simple screen saver using this excellent article to draw shapes.  I’ve decided to go from utilizing already produced code to doing something of my own.  My wife, who is a botanist at Iowa State was kind enough to loan me a Mac with Snow Leopard loaded, as school is out for the summer and they do not need this for their classes.  I asked her what she would like, and of course, it’s ferns (that’s the plant she studies).  Some quick thinking and googling lead me to the idea to use fractals!  In particular, Barnsley’s Fern.  To learn more, use google and this link.

Math drew this with a fractal equation, not by hand.

Now, as I have shown previously, I’m much better with Python, so to prototype the mathematical equation and code idea, I’ve developed a sample using pygame.  I found the math through this excellent code snippet, which saved me a lot of time in testing.  The use of the code is explained in the comments:

import random, pygame, time
from PIL import Image
from pygame.locals import *
from pygame.color import THECOLORS as color

mat = [[0.0,0.0,0.0,0.16,0.0,0.0,0.01],

xa = -5.5
xb = 6.5
ya = -0.5
yb = 10.5

x = 0.0
y = 0.0

imgx = 700
imgy = 700

k = 1
end = imgx*imgy / 10 * 4 # Looks like nothing is happening after this point.

screen = pygame.display.set_mode((imgx, imgy), 0, 8 )
pygame.display.set_caption('Fern Screensaver')

done = False
while not done:
    if k == end:
        k = 0
        p = random.random()
        if p <= mat[0][6]:
            i = 0
        elif p <= mat[0][6] + mat[1][6]:
            i = 1
        elif p <= mat[0][6] + mat[1][6] + mat[2][6]:
            i = 2
            i = 3
        x0 = x * mat[i][0] + y * mat[i][1] + mat[i][4]
        y = x * mat[i][2] + y * mat[i][3] + mat[i][5]
        x = x0
        jx = int((x-xa)/(xb-xa)*(imgx-1))
        jy = int(imgy-1)-int((y-ya)/(yb-ya)*imgy-1)
        c = color['white']
        screen.set_at((jx, jy), c)
    events = pygame.event.get()
    for e in events:
        if e.type == KEYDOWN and e.key == K_ESCAPE or e.type == QUIT:
            done = True
    k += 1


So, the next step is to code this for the Mac… keep posted for that code/tutorial.

Garmin Wardriver

For my birthday, my wife got me a GPS (Garmin Venture HC).  I have been disappointed in it’s integration with Linux, most particularly it’s ability to communicate with gpsd (usb input, not serial).  I had high hopes of doing some wardriving and kismet does not gather any of the data despite it’s configuration.  I can get gpsd to get some cryptic messages from the device but I found that this command: `gpsbabel -T -t garmin -f /dev/ttyUSB0` will generate the current coordinates.  So instead of getting frustrated, I’ve decided to open my first SourceForge project.  You can find it listed as Garmin Wardriver.

The concept seems simple enough, generate location through direct communication with the GPS device or through the gpsbabel command above and then gather a list of local ESSID’s with their strength.  With this data, updated each second, one could generate a location for entering an ESSID’s area, it’s strength as you move through and when out.  Output this to an overlay for a program such as Google Earth and that is a wardriver!  I can see this branching to more advanced uses but for the basic proof of concept, a command line program should suffice.  This will be written in Python and I’ve looked into utilizing the pygarmin and pywifi modules instead of generating information from preexisting programs.

Custom Brush for SyntaxHighlighter Evolved

Okay, before I get started let me just say that I realize there are several already set-up plugins for the WordPress Plugin, SyntaxHighlighter Evolved to include a brush for the *.batch language.  Also, there is a great article by the Plugin’s author that will guide you through developing a brush.  The reason I am posting mine is to pass a long a few things that went unsaid for the less experienced WordPress Plugin developer, but let me just say that this was much easier both in the plugin development and brush development than I thought it would be.  The reason I made my own brush, it’s just more fun to make my own!

Now, that being said, here we go!   My post for “Violating IT Policy” included a batch script for Cygwin to be portable.  since there was no brush in SyntaxHighlighter Evolved To develop a brush, you will need to set-up a new plugin for word press.  The plugin will be adopted by SyntaxHighlighter Evolved as you will see in a moment.  The structure for this plugin will be:

<root folder>/wp-content/plugins/
                        /plugins/<javascript brush>.js
                        /plugins/<php plugin>.php

For the javascript brush, this does have some tricky elements. but I’ve commented what I’m doing below.

/** shBrushBatch.js **/
/* Declare a new brush with SyntaxHighlighter.brushes.<your name for the brush> */
SyntaxHighlighter.brushes.Batch = function()
	/* Declare words that you need highlighted */
	var variable = 'clear cls goto set';
	var constants = 'if or';

	/* This is the heart of your brush, you can use the *.
	/* SyntaxHighlighter.regexLib.* brushes when applicapble. */
	this.regexList = [
		/* You may notice that my comments are looking for a css that does not match. */
		/* I'll explain below the script. */
		// comments
		{ regex: /(^::|rem).*$/gmi,                             css: 'string'},
		// stings
		{ regex: SyntaxHighlighter.regexLib.doubleQuotedString, css: 'comments'},
		{ regex: SyntaxHighlighter.regexLib.singleQuotedString, css: 'comments'},
		{ regex: /echo.*$/gmi,                                  css: 'keyword'},
		// variables
		{ regex: /%w+\1/gmi,                                    css: 'keyword'},
		{ regex: /%\*|%%?~?[fdpnxsatz]*[0-9a-z]\b/gmi,          css: 'keyword'},
		// clear cls keywords
		{ regex: new RegExp(this.getKeywords(variable), 'gmi'), css: 'variable'},
		// if and key words
		{ regex: new RegExp(this.getKeywords(constants), 'gmi'),css: 'constants'},
		// labels
		{ regex: /^:.+$/gmi,                                    css: 'script'}

/* Create the highlighter object. */
SyntaxHighlighter.brushes.Batch.prototype = new SyntaxHighlighter.Highlighter();
/* Set the Aliases */
SyntaxHighlighter.brushes.Batch.aliases = ['bat','batch'];

So the reason that my css does not match the actual of what it is would be because the theme does not match my preference.  I perfer comments to be green, so since the string for the RDark format is green, I had to assing my comments to the string.  This was pretty confusing but the way I figured out my color scheme was simple enough.  In <root>/wp-content/plugins/syntaxhighlighter/styles/ you will find all of the css files to coordinate with the theme.  Half way down, you will see “Actual Syntax Highlighter Colors” and it is at this point that you will want to see what all of your options are.  Rather than converting #5CE63B to green, I went and made a sample script once my plugin was complete, I then went and set up a color tester like this, in place of my normal brush file:

/** shBrushBatch.js  - color test version **/
SyntaxHighlighter.brushes.Batch = function()
	/* 	set your wordpress to:
			... continue until the last keyword ...
			1 I dropped the correct closing in the example for formatting. */
	var string = 'string';
	var comments = 'comments';
	// ... continue to the last keyword ...
	var keyword = 'color3';

	this.regexList = [
		{ regex: new RegExp(this.getKeywords(string), 'gmi'), 	 css: 'string'},
		{ regex: new RegExp(this.getKeywords(comments), 'gmi'),  css: 'comments'},
		// ... continue to the last keyword ...
		{ regex: new RegExp(this.getKeywords(color3), 'gmi'), 	 css: 'color3'}

SyntaxHighlighter.brushes.Batch.prototype = new SyntaxHighlighter.Highlighter();
SyntaxHighlighter.brushes.Batch.aliases = ['bat','batch'];

After doing this and seeing the colors, I could then associate which color I wanted for which sets of syntax.

Now, onto making the plugin work.  Obviously, you’ll need both of these files to have any results.  What this does is when you activate this plugin (yes, it does show in your plugins) then SyntaxHighlighter adopts it.  This script is pretty standard from what I saw online and is almost exactly out of the author’s blog post.  The comments at the front are what will appear in your WordPress under Plugins.  I’ve kept the comments mostly the same as the author, as he is describing it better than I could.

Plugin Name: Batch Brush - SyntaxHighlighter Evolved
Descriptionn:  Adds support for the Batch language to SyntaxHighlighter Evolved.
Author: Zachary D. Skelton
Version: 1.0.2
Author URI: http://www.skeltonnetworks.com/

// SyntaxHighlighter doesn't do anything until early in the "init" hook.

// Tell SyntaxHighlighter about this new brush.

// Register the brush with WordPress.
function syntaxhighlighter_batch_regscript() {
// Add alternative names for your brush.
function syntaxhighlighter_batch_addlang($brushes) {
	$brushes['batch'] = 'batch';
	$brushes['bat'] = 'batch';

	return $brushes;

At this point you should be able to load your page.  If it cannot find the brush (you’ll get a dialog to let you know), you could replace plugins_url() in line 19 with a string of a direct path to the file, but there should be no need for it.  The most common reason for this is an error in your javascript brush, so make sure to check that before going to insane.  After this is all done, you may have problems seeing the results.  It took me 5 loads of the correct format before I saw the change, in that case, deactivate the plugin, clear the cache, change the plugin version number in line 6 and re-activate the plugin.  Should not need all of that but some browsers are fussy, and that takes care of any problem with the cache. As I said before, this is well documented and relatively easy to make.  You can see that I made my plugin only apply to my script but it would be easy to add more things to it.  I used a lot of my regex directly from this plugin because that is a skill I’m still working on.  But this was surprisingly simple, and you can find lots of good information on making plugins of your own.  It is surprisingly not too tough!