Description:
------------
Functions ibase_fetch_object, ibase_fetch_row return wrong values when there is an empty string ('') in firebird table. When there is a 'null' value in the table this problem doesn't occure. 
PHP ver. 5.0.0 works fine, problem is in ver 5.0.4 and higher.
In this example in record number 3 there is value from record number 1 instead of empty string ('').




Reproduce code:
---------------
CREATE TABLE test_table (test_field VARCHAR(10))
Insert 4 records into test_table

rec_no|test_field
------------------
 1    | 'test1'
 2    | 'test2'
 3    | ''
 4    | 'test4'
------------------

$sql_string = "SELECT test_field FROM test_table";
$connection = ibase_connect($database, $user, $pass);

$dbo = ibase_query($connection, $sql_string);

while ( $oRow = ibase_fetch_object($dbo) )
{
   var_dump($oRow);
}


Expected result:
----------------
{ ["TEST_FIELD"]=> string(5) "test1" } 
{ ["TEST_FIELD"]=> string(5) "test2" } 
{ ["TEST_FIELD"]=> string(0) "" } 
{ ["TEST_FIELD"]=> string(5) "test4" } 


Actual result:
--------------
{ ["TEST_FIELD"]=> string(5) "test1" } 
{ ["TEST_FIELD"]=> string(5) "test2" } 
{ ["TEST_FIELD"]=> string(5) "test1" } 
{ ["TEST_FIELD"]=> string(5) "test4" }