diff --git a/include/flatbuffers/flatbuffers.h b/include/flatbuffers/flatbuffers.h
index 214ce267b71c27ffacc774a66fe37fe5a0a8efab..c1550f75ecfed55031629b32330b9b7aeb790bb8 100644
--- a/include/flatbuffers/flatbuffers.h
+++ b/include/flatbuffers/flatbuffers.h
@@ -1664,13 +1664,14 @@ const T *GetTemporaryPointer(FlatBufferBuilder &fbb, Offset<T> offset) {
/// This function is UNDEFINED for FlatBuffers whose schema does not include
/// a file_identifier (likely points at padding or the start of a the root
/// vtable).
-inline const char *GetBufferIdentifier(const void *buf) {
- return reinterpret_cast<const char *>(buf) + sizeof(uoffset_t);
+inline const char *GetBufferIdentifier(const void *buf, bool size_prefixed = false) {
+ return reinterpret_cast<const char *>(buf) +
+ ((size_prefixed) ? 2 * sizeof(uoffset_t) : sizeof(uoffset_t));
}
// Helper to see if the identifier in a buffer has the expected value.
-inline bool BufferHasIdentifier(const void *buf, const char *identifier) {
- return strncmp(GetBufferIdentifier(buf), identifier,
+inline bool BufferHasIdentifier(const void *buf, const char *identifier, bool size_prefixed = false) {
+ return strncmp(GetBufferIdentifier(buf, size_prefixed), identifier,
FlatBufferBuilder::kFileIdentifierLength) == 0;
}
diff --git a/include/flatbuffers/idl.h b/include/flatbuffers/idl.h
index 77e7422a471149bb73e03fbb098149e38e89fe50..4f569071037948952a97e0db93de922d1072c76a 100644
--- a/include/flatbuffers/idl.h
+++ b/include/flatbuffers/idl.h
@@ -387,6 +387,7 @@ struct IDLOptions {
std::string go_namespace;
bool reexport_ts_modules;
bool protobuf_ascii_alike;
+ bool size_prefixed;
// Possible options for the more general generator below.
enum Language {
@@ -442,6 +443,7 @@ struct IDLOptions {
skip_flatbuffers_import(false),
reexport_ts_modules(true),
protobuf_ascii_alike(false),
+ size_prefixed(false),
lang(IDLOptions::kJava),
mini_reflect(IDLOptions::kNone),
lang_to_generate(0) {}
diff --git a/src/flatc.cpp b/src/flatc.cpp
index 7b430a9217a93316209fdad046a25bff3bd84169..a164550e05e5b92c06ee3760ec5253818b787292 100644
--- a/src/flatc.cpp
+++ b/src/flatc.cpp
@@ -100,6 +100,7 @@ std::string FlatCompiler::GetUsageString(const char *program_name) const {
" (default is \"github.com/google/flatbuffers/go\")\n"
" --raw-binary Allow binaries without file_indentifier to be read.\n"
" This may crash flatc given a mismatched schema.\n"
+ " --size-prefixed Input binaries are size prefixed buffers.\n"
" --proto Input is a .proto, translate to .fbs.\n"
" --oneof-union Translate .proto oneofs to flatbuffer unions.\n"
" --grpc Generate GRPC interfaces for the specified languages\n"
@@ -233,6 +234,8 @@ int FlatCompiler::Compile(int argc, const char **argv) {
opts.one_file = true;
} else if (arg == "--raw-binary") {
raw_binary = true;
+ } else if (arg == "--size-prefixed") {
+ opts.size_prefixed = true;
} else if (arg == "--") { // Separator between text and binary inputs.
binary_files_from = filenames.size();
} else if (arg == "--proto") {
@@ -325,7 +328,7 @@ int FlatCompiler::Compile(int argc, const char **argv) {
"\" matches the schema, use --raw-binary to read this file"
" anyway.");
} else if (!flatbuffers::BufferHasIdentifier(
- contents.c_str(), parser->file_identifier_.c_str())) {
+ contents.c_str(), parser->file_identifier_.c_str(), opts.size_prefixed)) {
Error("binary \"" + filename +
"\" does not have expected file_identifier \"" +
parser->file_identifier_ +
diff --git a/src/idl_gen_text.cpp b/src/idl_gen_text.cpp
index 40afbf40ea89fab93f366c51abb20bb65beb6c35..6ef7f09678538b0f78fa268859fdfda2ce622ee9 100644
--- a/src/idl_gen_text.cpp
+++ b/src/idl_gen_text.cpp
@@ -263,8 +263,9 @@ bool GenerateText(const Parser &parser, const void *flatbuffer,
std::string &text = *_text;
assert(parser.root_struct_def_); // call SetRootType()
text.reserve(1024); // Reduce amount of inevitable reallocs.
- if (!GenStruct(*parser.root_struct_def_, GetRoot<Table>(flatbuffer), 0,
- parser.opts, _text)) {
+ auto root = parser.opts.size_prefixed ?
+ GetSizePrefixedRoot<Table>(flatbuffer) : GetRoot<Table>(flatbuffer);
+ if (!GenStruct(*parser.root_struct_def_, root, 0, parser.opts, _text)) {
return false;
}
text += NewLine(parser.opts);
diff --git a/src/idl_parser.cpp b/src/idl_parser.cpp
index 89e6e80d8969ecfec966ecaace9a6e48e42e910e..2607c0cd049b0d9e94ff40f1b1f55dc1ff2ff801 100644
--- a/src/idl_parser.cpp
+++ b/src/idl_parser.cpp
@@ -2412,9 +2412,15 @@ CheckedError Parser::DoParse(const char *source, const char **include_paths,
}
uoffset_t toff;
ECHECK(ParseTable(*root_struct_def_, nullptr, &toff));
- builder_.Finish(Offset<Table>(toff), file_identifier_.length()
- ? file_identifier_.c_str()
- : nullptr);
+ if (opts.size_prefixed) {
+ builder_.FinishSizePrefixed(Offset<Table>(toff), file_identifier_.length()
+ ? file_identifier_.c_str()
+ : nullptr);
+ } else {
+ builder_.Finish(Offset<Table>(toff), file_identifier_.length()
+ ? file_identifier_.c_str()
+ : nullptr);
+ }
} else if (IsIdent("enum")) {
ECHECK(ParseEnum(false, nullptr));
} else if (IsIdent("union")) {
@@ -2521,7 +2527,11 @@ void Parser::Serialize() {
builder_.CreateString(file_identifier_),
builder_.CreateString(file_extension_),
root_struct_def_ ? root_struct_def_->serialized_location : 0);
- builder_.Finish(schema_offset, reflection::SchemaIdentifier());
+ if (opts.size_prefixed) {
+ builder_.FinishSizePrefixed(schema_offset, reflection::SchemaIdentifier());
+ } else {
+ builder_.Finish(schema_offset, reflection::SchemaIdentifier());
+ }
}
Offset<reflection::Object> StructDef::Serialize(FlatBufferBuilder *builder,