gsm48_decode_bcd_number2: fix ENOSPC edge case

Return ENOSPC if the decoding buffer is one byte too small, instead of
returning 0 and silently truncating the string. Add a new "truncated"
variable to detect if the loop breaks in the final iteration.

The string is not truncated if there is exactly one 0xf ('\0') higher
nibble remaining. This is covered by the existing test case "long
15-digit (maximum) MSISDN, limited buffer".

Related: OS#4049
Change-Id: Ie05900aca50cc7fe8a45d17844dbfcd905fd82fe

0 files changed, 0 insertions, 0 deletions