Function apr_base64_encode 

pub unsafe extern "C" fn apr_base64_encode(
    coded_dst: *mut c_char,
    plain_src: *const c_char,
    len_plain_src: c_int,
) -> c_int

Encode a text string using base64encoding. @param coded_dst The destination string for the encoded string. @param plain_src The original string in plain text @param len_plain_src The length of the plain text string @return the length of the encoded string