Fix bug #55138 PDO OCI cannot insert more than 1332 bytes

[gureedo]

According to Oracle docs value_sz defines size in bytes, not characters.
OCIBindByName() docs:
http://docs.oracle.com/cd/E16655_01/appdev.121/e17625/oci16rel003.htm#LNOCI17140

value_sz (IN)
The maximum size possible in bytes of any data value (passed using valuep) for this bind variable. 
This size is always expected to be the size in bytes. 

This fix not covers VARCHAR2 extended mode in new Oracle versions.
See max_string_size = extended at
http://docs.oracle.com/cd/E16655_01/appdev.121/e17625/oci03typ.htm#LNOCI16271

[smalyshev]

@gureedo would you mind to add a test for it - from code in bug report https://bugs.php.net/bug.php?id=55138 ?

[gureedo]

After reading docs more carefully I think implicit value with 4000 bytes is wrong as it does not show real length with different encodings.
From http://docs.oracle.com/cd/E16655_01/appdev.121/e17625/oci05bnd.htm#LNOCI16429

When you specify the OCI_DATA_AT_EXEC mode in a call to OCIBindByPos() or OCIBindByName(), 
the value_sz parameter defines the total size of the data that can be provided at run time. 
The application must be ready to provide to the OCI library the run time IN data buffers
on demand as many times as is necessary to complete the operation. When the allocated 
buffers are no longer required, they must be freed by the client.

So we can put into value_sz max value as it type can fit.

[ghost]

Can one of the admins verify this patch?

[krakjoe]

@gureedo can you fix conflicts please :)

Also, can I know the current status of this PR exactly ?

[gureedo]

Oops, same issue as in #542. Wating for response.

[krakjoe]

Please do create a clean PR, closing this one for you.

FWIW, I'm not sure why pushing to the branch didn't work.