Description:
------------
I have been using base64_encode/decode for the past 2 years to 
pass complex SQL statements in href links between scripts 
running under php 5.0.4.  After upgrading to 5.1.2 I 
experienced errors and missing data using the same functions.  
I get the same results in php 5.1.4.

It appears that data is being lost or garbled in either the 
encode or decode.

This problem does NOT occur on our production server running 
5.0.4.

NOTE: Unable to post code to reproduced bug on production 
server as we cannot install 5.1.x if there is a problem.  I 
tried to keep it as short as possible and illustrate the bug. 

Reproduce code:
---------------
// base64_bug1.php - Demo bug with base64_encode/decode
//--------------
$query = "SELECT DISTINCT class.class_no, class.status, class.class_id, class.sess_group, class.short_desc, class.classroom, class.ages, class.capacity, csc.beg_date, csc.end_date, csc.end_date_infinite_flag, csc.open_sched_flag, ins.lname, ins.fname, CONCAT(ins.fname,' ',ins.lname) AS ins_full_name, csc.w_mon, csc.w_mon_time, csc.w_mon_duration, csc.w_tue, csc.w_tue_time, csc.w_tue_duration, csc.w_wed, csc.w_wed_time, csc.w_wed_duration, csc.w_thu, csc.w_thu_time, csc.w_thu_duration, csc.w_fri, csc.w_fri_time, csc.w_fri_duration, csc.w_sat, csc.w_sat_time, csc.w_sat_duration, csc.w_sun, csc.w_sun_time, csc.w_sun_duration FROM class_sched_cfg AS csc, class LEFT JOIN class_sched AS cs ON class.class_id = cs.class_id LEFT JOIN class_instruct AS ci ON (class.class_id = ci.class_id AND ci.primary_ins_flag = 1) LEFT JOIN instructor AS ins ON ci.ins_id = ins.ins_id WHERE class.co_id = 55555 AND class.class_id = csc.class_id AND (((cs.beg_time > '01:00:00' AND cs.beg_time < '23:00:00') OR (cs.end_time > '01:00:00' AND cs.end_time < '23:00:00')) OR (cs.beg_time <= '01:00:00' AND cs.end_time >= '23:00:00')) AND sess_group LIKE 'spring/summer%' AND (class.status = 'A' AND CURDATE() <= csc.end_date) ORDER by short_desc";

$tmp = base64_encode($query);
echo "<a href='base64_bug2.php?query=".$tmp."'>Pass Data</a>";
?>

// base64_bug2.php - Demo bug with base64_encode/decode
//--------------
echo "<b>We should get our original encoded Value back.<br/>Encoded Value Prior to base64_decode:</b><br/> ".$_REQUEST['query'];

$query = base64_decode($_REQUEST['query']);

echo "<p><b>Value After base64_decode:</b><br/> ".$query;
echo "<p><a href='encode_bug1.php'>Back to Step 1</a>";
?>

Expected result:
----------------
I should have gotten my original SQL string back after 
executing the base64_decode().  I get part of the string back 
with the last couple lines garbled with crazy characters.

Actual result:
--------------
I get part of the original string back with the last couple 
lines garbled with crazy characters.  Here is the actual 
output from script base64_bu2.php:

SELECT DISTINCT class.class_no, class.status, 
class.class_id, class.sess_group, class.short_desc, 
class.classroom, class.ages, class.capacity, csc.beg_date, 
csc.end_date, csc.end_date_infinite_flag, 
csc.open_sched_flag, ins.lname, ins.fname, CONCAT
(ins.fname,' ',ins.lname) AS ins_full_name, csc.w_mon, 
csc.w_mon_time, csc.w_mon_duration, csc.w_tue, 
csc.w_tue_time, csc.w_tue_duration, csc.w_wed, 
csc.w_wed_time, csc.w_wed_duration, csc.w_thu, 
csc.w_thu_time, csc.w_thu_duration, csc.w_fri, 
csc.w_fri_time, csc.w_fri_duration, csc.w_sat, 
csc.w_sat_time, csc.w_sat_duration, csc.w_sun, 
csc.w_sun_time, csc.w_sun_duration FROM class_sched_cfg AS 
csc, class LEFT JOIN class_sched AS cs ON class.class_id = 
cs.class_id LEFT JOIN class_instruct AS ci ON 
(class.class_id = ci.class_id AND ci.primary_ins_flag = 1) 
LEFT JOIN instructor AS ins ON ci.ins_id = ins.ins_id WHERE 
class.co_id = 55555 AND class.class_id = csc.class_id AND 
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