add flatbuffers

commit 6da1cf79d90eb242e7da5318241d42279a3df3ba
Author: Max Burke <max@urbanlogiq.com>
Date:   Sun Jan 19 14:47:28 2020 -0800

    [rust] Add use declarations to Rust-generated bindings for imported FB definitions (#5645)

    * Bugfix for Rust generation of union fields named with language keywords

flatbuffers/samples/sample_text.cpp

@@ -0,0 +1,58 @@
+/*
+ * Copyright 2014 Google Inc. All rights reserved.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "flatbuffers/idl.h"
+#include "flatbuffers/util.h"
+#include "monster_generated.h"  // Already includes "flatbuffers/flatbuffers.h".
+
+using namespace MyGame::Sample;
+
+// This is an example of parsing text straight into a buffer and then
+// generating flatbuffer (JSON) text from the buffer.
+int main(int /*argc*/, const char * /*argv*/[]) {
+  // load FlatBuffer schema (.fbs) and JSON from disk
+  std::string schemafile;
+  std::string jsonfile;
+  bool ok = flatbuffers::LoadFile("samples/monster.fbs", false, &schemafile) &&
+            flatbuffers::LoadFile("samples/monsterdata.json", false, &jsonfile);
+  if (!ok) {
+    printf("couldn't load files!\n");
+    return 1;
+  }
+
+  // parse schema first, so we can use it to parse the data after
+  flatbuffers::Parser parser;
+  const char *include_directories[] = { "samples", nullptr };
+  ok = parser.Parse(schemafile.c_str(), include_directories) &&
+       parser.Parse(jsonfile.c_str(), include_directories);
+  assert(ok);
+
+  // here, parser.builder_ contains a binary buffer that is the parsed data.
+
+  // to ensure it is correct, we now generate text back from the binary,
+  // and compare the two:
+  std::string jsongen;
+  if (!GenerateText(parser, parser.builder_.GetBufferPointer(), &jsongen)) {
+    printf("Couldn't serialize parsed data to JSON!\n");
+    return 1;
+  }
+
+  if (jsongen != jsonfile) {
+    printf("%s----------------\n%s", jsongen.c_str(), jsonfile.c_str());
+  }
+
+  printf("The FlatBuffer has been parsed from JSON successfully.\n");
+}