These methods worked in a very strict way for some encodings, and in a
very very loose way for others. E.g. when converting from hex-encoded
UCS-2, we would attempt to convert as much text as we could even if
the input string was truly not even close to UCS-2. This kind of "do
our best" could make sense when processing e.g. the operator name
reported by the modem, as that is some string to show to the user and
there may be no strict requirement to have it perfectly fine. But the
kind of loose comparison done for UCS-2 doesn't make sense e.g. when
converting USSD responses or SMS messages.
If the conversion is not fully compatible, the user of the method
needs to request transliteration enabled explicitly in order to avoid
returning errors in this method.
Until now, this method would automatically apply transliteration;
i.e. replacing characters with '?' when no direct translation was
available.
We can attempt to do that transliteration on strings that are not
critical, e.g. the operator name reported by the network. But we
should not do that on other types of strings, e.g. on SMS contents
that may really have additional purposes than just being
human-readable.
This commit makes the transliteration option to be explicitly
requested by the caller.
There's no point in adding a quoting option to this method; if the
caller needs the appended string quoted, it should quote it before
passing it to this method.
It was nowhere used anyway.
Most of all the other APIs we have are expecting binary data (e.g.
UCS-2 encoded strings) in ASCII hex format, because they were going
to be used in text AT commands. For binary protocols allowing binary
data, we need use a more generic API that provides an explicit data
size.
Instead of having a method that returns the expected length after the
conversion and the amount of input UTF-8 characters that couldn't be
converted to the given charset, simplify the logic and just define a
method that returns a boolean specifying whether the conversion is
possible or not.
Also, include unit tests.
Some modems return the +COPS operator name in hex-encoded current
character set (as set with +CSCS). Others return the operator name
in ASCII when set to UCS2, while yet others return the ASCII name
with trash at the end (*cough* Huawei *cough*). Handle that better
by not crashing.
This method will try to convert the input string to UTF-8. The input string is
supposed to be in the given charset; or otherwise is supposed to be the hex
representation of the string in the given charset.
Change interface to take the number of GSM characters
rather than the number of octets, so that it is possible to
distinguish the 7-character and 8-character cases.
Aleksander Morgado
Dan Williams
Aleksander Morgado
Nathan Williams