Itunes like progress/capcity bar

By mike@mike-miles.com

Back in December I was working on a project that needed to show progress bars.  They progress bars had to show the progress of multiple items, and it was explained to me that they should resemble the percentage bars in iTunes that show how full your ipod / iphone is, like so;

Not a problem I thought to myself, all I needed was a few images and the ever useful PHP GD library .  If you’ve never used the PHP GD library before, a brief overview:  It’s a graphics library that allows you to create dynamic graphics.  (Told you it was brief).

Of course the great thing about PHP is that it is open source, so anything you need todo has already practaclly been done. After googling I found this percentage bar code created by netlobo.com, as well as this progress/percentage bar WebAppers (theirs was in javascript but it gave me a starting point). Both of these were close to what I wanted to do, I just needed to tweak and combine them.

I should note, that since I did use code from both those websites (which are covered under the Creative Commons license and GNU General Public License) this code covers the same licensing.

The Process

My thought process for creating this was pretty straight forward from the get-go.

1. Get percents of the items that will be on the bar
2. Create a “bucket” image
3. for each percent, fill part of the bucket with a color
4. Output the whole bar.

And that’s pretty much the route I followed.  It was pretty simple actually.

Sorry to say, this code has been removed for legal reasons

but, please check out the sources I used when developing my code (they are mentioned above)

fseek()

By mike@mike-miles.com

There is this nifty function in PHP called fseek().  It allows you to set a pointer to any where in a file (a text file for example).  It comes in handy when your dealing with very large files (like log files, or config files), and today I discoverd it can be very useful if you want to search throu a file backwards.

Which was exactly what I was trying to do.  I needed to traverse a file, starting at the end.  The only solutions I could find infolved reading the whole file into an array, reversing the array and thensearching that way, which completly nullified the point of going the end of the file (I had to read the whole file into memory to get the end).

The solution I came up with, involves using fseek() and fread() (which allows you to read a file byte by byte).  With this function you give it a file, and a string to search for, and it’ll go through the file backwards byte by byte, and return the pointer (byte location in the file) of where the search string occures. (if it doesnt find the string, it’ll return FALSE

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<?PHP
function searchFromEnd($filename,$search){
	//first make sure that the file is there, and we can read it
	if(file_exists($filename) && is_readable($filename)){ 
		//open the file for reading
		$fp = fopen($filename,'r');
		//get the length of the search string(minus the first character)
		$size=strlen($search)-1; 
		//get first element in string
		$first=$search[0]; 
		//size of the file
		$file_size=filesize($filename); 
		//set seek pointer to end of the file - size of the string
		$seek=$file_size-$size; 
		//set found to FALSE
		$found=false;
		//while not past the begining of the file
		while($seek>=0){
			//set file pointer to seek value
			fseek($fp,$seek); 
			//read in the first byte from pointer
            $test=fread($fp,1); 
            //if byte is same as the first string character, and  back far enough in file for search length
			if($test==$first && (($seek+$size) <= $file_size) ){ 
				//append enough characters to $test to make it same size as $search
				$test.=fread($fp,$size); 
				//if test value is what we're looking for
				if(strcmp($test,$search)==0){ 
					//return position;
					$found=$seek;
					//set pointer to -1 (exit loop);
					$seek=-1; 
				}else{
					//move back a byte
					$seek--; 
				}
			}else{
				//move back a byte
				$seek--; 
			}
		}
		//close the file
		fclose($fp); 
	}
	//return FALSE or position of search string
	return $found; 
}
?>

A much better method then reading the whole file.

You can download this file from here