Description:
------------
When assigning the value returned from odbc_result to a variable and the result value size is less than the current odbc_longreadlen size, the full longreadlen memory amount is allocated instead of the smaller amount.

To fix this, if SQLGetData returns SQL_SUCCESS, we can use the length in vallen to reallocate the memory for field to vallen, i.e. inserting the lines 

} else if (rc == SQL_SUCCESS) {
	field = erealloc(field, result->values[field_ind].vallen);

after the rc == SQL_NO_DATA_FOUND check.  I've included a patch file, but I'm not sure if I created that correctly.  I've recompiled with this patch and the bug appears to be fixed.

Test script:
---------------
<?php
ini_set("memory_limit","1048576");
ini_set( "odbc.defaultlrl", "4096" );
$data = '0';
$db = odbc_connect('DSN', 'user', 'pass');
odbc_exec($db, 'CREATE TABLE Temp (contents long varchar)');
odbc_exec($db, 'INSERT INTO Temp (contents) VALUES (\'' . $data . '\')');
$rst = odbc_exec($db, 'select * from Temp');
$contentArray = Array();
for($i = 0; $i < 1024; $i++){
	odbc_fetch_row($rst,1);
	$contentArray[] = odbc_result($rst, 'contents');
}
odbc_free_result($rst);
echo count($contentArray);
?>

Expected result:
----------------
1024

Actual result:
--------------
Fatal error: Allowed memory size of 1048576 bytes exhausted (tried to allocate 4096 bytes) in D:\memLeakTest.php on line 12