Description:
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Reading a BLOB column which is bigger than 1048576 bytes (this number is defined as PHP_OCI_LOB_BUFFER_SIZE in php_oci8_int.h) with ocifetchinto function with mode OCI_RETURN_LOBS, returned blob column always have a size of 1048576.

This is definitely a bug in oci8_lob.c:php_oci_lob_get_length() function (as php_oci_lob_read is called from oci8_interface.c with read_length =-1) or in a reading loop in oci8_lob.c:php_oci_lob_read function.

Reproduce code:
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$data = array();
$conn = OCIPLogon("user", "pass", "db");
$query = "SELECT BLOB_COLUMN FROM t WHERE ID=:id";

$cur = OCIParse($conn, $query);
OCIBindByName ($cur, ':id', $id, 4000);
$er = OCIExecute($cur);
if (!$er) print_r(OCIError($cur));
OCIFetchInto($cur, $data, OCI_ASSOC + OCI_RETURN_NULLS + OCI_RETURN_LOBS);
OCIFreeStatement($cur);

echo strlen($data['BLOB_COLUMN']);

Expected result:
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Returned length of $data['BLOB_COLUMN'] should be the original length of the BLOB_COLUMN in table t.

Actual result:
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Returned length of $data['BLOB_COLUMN'] is always 1048576 bytes.