The result of parsing UTF-16 encoded input lacks the last character

[fktn-k]

Description

When UTF-16 encoded characters which do not end with a surrogate pair are passed for deserialization, the last character is not parsed.
While digging into the issue, it's turned out this is caused due to inadequate implementation of conversion from UTF-16 to UTF-8 which tries to take care of surrogate pairs.

Reproduction steps

Try parsing any UTF-16 encoded characters which do not end with a surrogate pair, like the following:

fkyaml::node n = fkyaml::node::deserialize(u"foo: bar");
std::cout << n << std::endl;

Expected vs. actual results

Expected output:

foo: bar

Actual output:

foo: ba

Minimal code example

The same as "Reproduction steps".

Error messages

No error messages.

Compiler and operating system

GCC 11.4.0 on Ubuntu 22.04 LTS

Library version

develop HEAD

Validation

• The bug also occurs if the latest version from the develop branch is used.
• I can successfully compile and run the unit tests.

[fktn-k]

The bug reported in this issue has been fixed in #234.