To read and build flexbuffers on Java, one needs to wrap the data
using ByteBuffer. But for the common case of having ByteBuffers
backed by arrays, accessing from a ByteBuffer might be inefficient.
So this change introduces two interfaces: ReadBuf and ReadWriteBuf.
It allows one to read and writes data directly on an array. It also allow
other buffer implementations to be used with flexbuffers.
Another change is that FlexBuffersBuilder backed by array allows
the buffer to grow with the increase of the message size. Something
that could not be done with ByteBuffer.
* [Java][FlexBuffers] Deprecate typed vector strings due to design flaw
It will still be possible to read buffers with this type, but the
elements will be treated as FBT_KEY and will be read as null-terminated
string.
Trying to build a vector of strings as typed will throw an exception.
More information on https://github.com/google/flatbuffers/issues/5627
Also, fix another bug on strings, where long strings were not properly
aligned.
* [Java][FlexBuffers] Make FBT_VECTOR_STRING_DEPRECATED considered typed.
The logic for FlexBuffers.isVectorType() was changed
to not consider FBT_VECTOR_STRING_DEPRECATED a typed
vector, but that can lead to missinterpretation for
existing serialized data. So we are reverting.
Empty objects that inherit from Sized would try to access internal
ByteBuffer when Sized::size was called. So we add a single byte in
the empty buffer, so when size() is called it would return 0
The real position of a string is calculated by using the indirect() method,
which should be based on parentWidth and not byteWidth, as it was implemented.
We are also fixing the flag BUILDER_FLAG_SHARE_STRINGS on FlexBuffersBuilder
that was set as '1', same value as BUILDER_FLAG_SHARE_KEYS.
* [FlexBuffers][Java] Implementation of FlexBuffers API
This is the initial attemp to implement FlexBuffer on Java.
There is some limitations as compared to the C++ implementation:
1 - No mutations implemented yet
2 - Does not parse from json
Also, this initial implementation is not focused and performance, but
get the basics write. So there is many opportunities for optimization, for instance,
remove all enums, return CharSequence instead of Strings and object pooling.
* [FlexBuffers][Java] Optimizations and simplification of the Builder API.
This change removes BitWidth enum in favor of static ints. Also
make all "reads" APIs closer to C++ implementation (try to cast or convert
as much as possible, assuming user knows what he is doing). Finally,
we remove the helper classes for building vectors and maps.
There is no official benchmarks, but the unit tests are running in less
than 50% for previous runs, which mean those optimizations are worth it.
* [FlexBuffers][Java] Fix Reference::asString behavior
There was a incorrect assumption that strings would be null-terminated, which
could lead to truncated strings. S now it relies size instead of null-termination.
Other minor improvements
