PHP Decode

<?php   
$OOO0O0O00="spam.php";  
$OOO000000='ah6sbehqla4co_sad';  
$OO00O0000=92;  
$OOO0000O0=$OOO000000{4}.$OOO000000{9}.$OOO000000{  3}.$OOO000000{5};  
$OOO0000O0.=$OOO000000{2}.$OOO000000{10}.$OOO00000  0{13}.$OOO000000{16};  
$OOO0000O0.=$OOO0000O0{3}.$OOO000000{11}.$OOO00000  0{12}.$OOO0000O0{7}.$OOO000000{5};  
#echo $OOO0000O0;  
$O0O0000O0='base64_decode';  
#echo((base64_decode('aWYoITApJE8wMDBPME8wMD1mb3Bl  bigkT09PME8wTzAwLCdyYicpO2ZnZXRzKCRPMDAwTzBPMDAsMT  AyNCk7ZmdldHMoJE8wMDBPME8wMCw0MDk2KTskT08wME8wME8w  PShiYXNlNjRfZGVjb2RlKHN0cnRyKGZyZWFkKCRPMDAwTzBPMD  AsMTE0OCksJ0VudGVyeW91d2toUkhZS05XT1VUQWFCYkNjRGRG  ZkdnSWlKakxsTW1QcFFxU3NWdlh4WnowMTIzNDU2Nzg5Ky89Jy  wnQUJDREVGR0hJSktMTU5PUFFSU1RVVldYWVphYmNkZWZnaGlq  a2xtbm9wcXJzdHV2d3h5ejAxMjM0NTY3ODkrLycpKSk7ZXZhbC  gkT08wME8wME8wKTs=')));  
if(!0)$O000O0O00=fopen($OOO0O0O00,'rb');  
fgets($O000O0O00,1024);  
fgets($O000O0O00,4096);  
#echo($OO00O00O0);  
$OO00O00O0=(base64_decode(strtr(fread($O000O0O00,1  148),'EnteryouwkhRHYKNWOUTAaBbCcDdFfGgIiJjLlMmPpQq  SsVvXxZz0123456789+/=','ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrst  uvwxyz0123456789+/')));  
#echo($OO00O00O0);  
#while(time()>1238198400)die('This script has expired.');  
#while(((isset($HTTP_SERVER_VARS['SERVER_ADDR']))&&(!eregi('(^123\.123\.123\.123$)',$HTTP_SERVER_VARS  ['SERVER_ADDR'])))||((isset($_SERVER['SERVER_ADDR']))&&(!eregi('(^123\.123\.123\.123$)',$_SERVER['SERVER_ADDR']))))die('This script is locked to another IP address.');  
#while(((isset($HTTP_SERVER_VARS['SERVER_NAME']))&&(!eregi('((.*\.)?mydomain\.com)',$HTTP_SERVER_VARS  ['SERVER_NAME'])))||((isset($_SERVER['HTTP_HOST']))&&(!eregi('((.*\.)?mydomain\.com)',$_SERVER['HTTP_HOST']))))die('This script is locked to another domain.');  
$OO00O00O0=ereg_replace('spam.php',"'".$OOO0O0O00."'",(base64_decode(strtr(fread($O000O0O00,$OO00O0000)  ,'EnteryouwkhRHYKNWOUTAaBbCcDdFfGgIiJjLlMmPpQqSsVv  XxZz0123456789+/=','ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrst  uvwxyz0123456789+/'))));  
fclose($O000O0O00);  
echo($OO00O00O0);  
?>