A PHP progress bar

progressbar.inc

<?php

require_once( "termcolours.inc" );

class ProgressBar
{
	protected $ticktime = false;
	
	protected $exp;
	protected $xsquare;
	
	protected $count = 0;
	protected $max = 100;
	protected $lmax = 0;
	
	protected $variance = 0;
	
	protected $line_size = 80;
	protected $line_pos = 0;
	
	public function __construct( $max = 100 )
	{
		$this->reset( $max );
	}
	
	public function reset( $max = 100 )
	{
		$this->max = $max;
		$this->lmax = (floor(log10($max))+1); // number of digits in $max;
		
		$this->exp = new Expectation();
		$this->xsquare = new Expectation();
		$this->stop();
		$this->start();
	}
	
	public function start()
	{
		if ( $this->ticktime !== false )
			throw new Exception( "Timer already started." );
		
		$this->ticktime = microtime( true );
		$this->detect_line_size();
	}
	
	public function stop()
	{
		if ( $this->line_pos > 0 )
			$this->big_tick();
		
		$this->ticktime = false;
		
		$this->line_pos = 0;
	}
	
	public function tick()
	{
		$this->count++;
		
		$time = microtime(true) - $this->ticktime;
		
		// Update expected value and variance
		$delta = $this->exp->point( $time );
		$this->xsquare->point( $time * $time );
		
		if ( $this->variance <= 0 )
			print( "." );
		elseif ( $delta < -1*($this->variance) )
			print( green(".") );
		elseif ( $delta < $this->variance )
			print( "." );
		elseif ( $delta < 2*$this->variance )
			print( yellow(".") );
		else
			print( bred(".") );
			
		$this->line_pos++;
		if ( $this->line_pos == $this->line_size )
			$this->big_tick();
		
		$this->ticktime = microtime(true);
	}
	
	protected function detect_line_size()
	{
		@list($height,$width) = explode(" ",shell_exec("stty size 2>/dev/null"));
		if ( !$width || $width < 40 )
			$width = 80;
		
		$infobox_size = 2 +            //  Left spacing
			1 +                        //  [
			(2 * $this->lmax) + 1 +    //    "123/456" progress indicator
			1 +                        //     a space
			6 +                        //    "(100%)" progress indicator
			1 +                        //     another space
			4 + (2+1+2+1) +            //    "ETA 10m24s" progress indicator
		//	1 +                        //     yet another space
			1 +                        //  ]
			1;                         //  Right spacing
		
		$this->line_size = $width - $infobox_size;
	}
	
	protected function big_tick()
	{
		$exp = $this->exp->exp();
		$this->variance = sqrt( ($this->xsquare->exp()) - ($exp*$exp) );
		
		print( str_repeat(" ",($this->line_size - $this->line_pos)) );
		print( "  [" );
		
		print( str_pad( "{$this->count}/{$this->max}", (2 * $this->lmax) + 1, " ", STR_PAD_LEFT ) . " " );
		
		$perc = floor( 100 * ($this->count / $this->max) );
		print( str_pad( "({$perc}%)", 6, " ", STR_PAD_LEFT ) . " " );
		
		print( "ETA " . $this->format_time($this->ETR()) );
		
		print( "]\n" );
		$this->line_pos = 0;
	}
	
	/**
	 * Estimate Time Remaining   (in seconds)
	 * 
	 * Calculates a pessimistic average of the average time between ticks, and
	 * multiplies that time by the number of ticks remaining.
	 **/
	protected function ETR()
	{
		$count = $this->max - $this->count;
		if ( $count <= 0 ) return 0;
		
		return $count * ( $this->exp->exp() + sqrt($this->xsquare->exp()) );
	}
	
	protected function format_time( $time )
	{
		if ( $time < 3600 )
		{
			$s = str_pad( floor($time % 60), 2, "0", STR_PAD_LEFT );
			$m = str_pad( floor($time / 60), 2, " ", STR_PAD_LEFT );
			return "{$m}m{$s}s";
		}
		if ( $time < 86400 )
		{
			$m = str_pad( round(($time % 3600)/60), 2, "0", STR_PAD_LEFT );
			$h = floor($time / 3600);
			if ( $m >= "60" )
			{
				$m = "00";
				$h++;
			}
			$h = str_pad( $h, 2, " ", STR_PAD_LEFT );
			return "{$h}h{$m}m";
		}
		if ( $time < 86400*30 )
		{
			$h = str_pad( round(($time % 86400)/3600), 2, "0", STR_PAD_LEFT );
			$d = floor($time / 86400);
			if ( $h >= "24" )
			{
				$h = "00";
				$d++;
			}
			$d = str_pad( $d, 2, " ", STR_PAD_LEFT );
			return "{$d}d{$h}h";
		}
		if ( $time < 86400*365 )
		{
			$d = str_pad( round(($time % 86400*30)/86400), 2, "0", STR_PAD_LEFT );
			$m = floor($time / 86400*30);
			if ( $d >= "30" )
			{
				$d = "00";
				$m++;
			}
			$m = str_pad( $d, 2, " ", STR_PAD_LEFT );
			return "{$m}m{$d}d";
		}
		$m = str_pad( round(($time % 86400*365)/86400*30), 2, "0", STR_PAD_LEFT );
		$y = floor($time / 86400*365);
		if ( $m >= 12 )
		{
			$m = "00";
			$y++;
		}
		$y = str_pad( $d, 2, " ", STR_PAD_LEFT );
		return "{$y}y{$d}d";
	}
}

class Expectation
{
	private $count = 0;
	private $sum = 0;
	
	public function point( $p )
	{
		$this->count++;
		$this->sum += $p;
		
		return $p - $this->exp();
	}
	
	public function exp()
	{
		return $this->sum / $this->count;
	}
}




if ( basename(@$argv[0]) == basename(__FILE__) )
{
	$max = mt_rand( 150, 500 );
	$pb = new ProgressBar( $max );
	
	require_once( "stats.inc" );
	$av = pow( 1.25, mt_rand( 40, 61 ) );
	$sd = $av * 0.15;
	
	for ( $i = 0; $i < $max; $i++ )
	{
		usleep( St::normal( $av, $sd ) );
		$pb->tick();
	}
	$pb->stop();
}