Banner rotator

CREDITS BANNER URL
999999995 b1.gif www.milliondollarsurfer.com
999999994 b2.gif www.gamesandstuff.com
994 b3.gif www.belengonzalezauto.com

-------------------------- ROTATOR.PHP ----------------------------


<?php


// BANNER ROTATOR V1.0
// Displays multiple advertisers banners on your site by how many credits they have
// License : Freeware
// Banners are randomly displayed from directory ROTATOR
// Credits count down and banners stop displaying when their credits are used up
// Requires your server to run PHP and your web page must have extension .php


// INSTALL
// Upload this file as rotator.php
// Create directory rotator under the directory where this script is used
// Create a text file rotator/rotator.txt
// Make the 1st line CREDITS BANNER URL
// Insert the following line where you want the banner displayed on your page
// <?php include("rotator.php"); ? >
// (no space between ? >)


//----------------------------------------------------------------------


// Example of rotator.txt


// CREDITS BANNER URL
// 90 mbannr.gif www.milliondollarhosting.com
// 95 games1.gif www.gamesandstuff.com
// 0 sharkfins.gif www.sharks.com


// If all credits are 0 then 1st banner is displayed
// For free advertising you can set default banner(s) with 999999999 credits


$strFile1 = "rotator/rotator.txt";


//-------------------------------------------------------------------------


// open for read
$objFH = fopen( $strFile1, "r" );
$strBuffer1 = fread( $objFH, filesize( $strFile1 ) );
fclose( $objFH );


// tally number of banners with credits, by counting rows in rotator.txt
$myeof = true;
$tosay = $strBuffer1;
$numbanners = -1;
while ($myeof) {


$nextret = strpos($tosay, "\n");
$say = substr($tosay, 0, $nextret);
$tosay = substr($tosay, $nextret+1);
if ($say[0] != '0') $numbanners++;
if (strpos($tosay, "\n") == 0) $myeof=false;



}


//-------------------------------------------------------------------------

// select banner and subtract 1 credit from rotator.txt
$myeof = true;
$tosay = $strBuffer1;
$checked = 0;
$selectedban = "";
$freeban = "";
$strBuffer2 = "";
while ($myeof) {


$nextret = strpos($tosay, "\n");
$say = substr($tosay, 0, $nextret);
$tosay = substr($tosay, $nextret+1);
$pcred = strpos($say, " ");
$pban = strpos($say, " ", $pcred+1);
$creds = substr($say, 0, $pcred);
$bans = substr($say, $pcred+1, $pban-$pcred-1);
$urls = substr($say, $pban+1);


// 1 chance in number-of-remaining-banners to be selected
if (($selectedban=="") && is_numeric($creds) && (rand($checked, $numbanners-1) == $checked)) {


if ($creds > 0) {
$tax = 0 - 1 + $creds;
$selectedban = $bans;
$selectedurl = $urls;
}
else {
$tax = 0;
}
$strBuffer2.= $tax . " " . $bans . " " . $urls . "\n";
if ($freeban == "" ) {
$freeban = $bans;
$freeurl = $urls;
}
}
else {
$strBuffer2.= $say . "\n";
}


if (is_numeric($creds) && ($creds>0)) $checked++;
if (strpos($tosay, "\n") == 0) $myeof=false;



}


if ($selectedban == "") {
$selectedban = $freeban;
$selectedurl = $freeurl;


}


//------------------------------------------------------------------------

// open for write
$objFH = fopen( $strFile1, "w" );
fwrite( $objFH, $strBuffer2 );
fclose( $objFH );


?>

<a href="http://<? echo $selectedurl; ?>"><img src="rotator/<? echo $selectedban; ?>" height=60 width=468
border=0></a>