Implementation:Alibaba MNN FlatBuffers Reflection Header

Knowledge Sources	Alibaba_MNN FlatBuffers
Domains	Serialization, Reflection
Last Updated	2026-02-10 12:00 GMT

Overview

Full reflection API enabling runtime schema introspection and dynamic field access on FlatBuffer objects.

Description

reflection.h provides utilities for accessing FlatBuffer data dynamically using a binary schema (a .bfbs file compiled by flatc). It includes functions to get and set fields by name or index at runtime, resize vectors, and copy tables between buffers. This is more powerful than mini-reflection but requires shipping the binary schema alongside the data.

Usage

Vendored dependency used internally by MNN for model serialization. Not directly imported by end users.

Code Reference

Source Location

• Repository: Alibaba_MNN
• File: 3rd_party/flatbuffers/include/flatbuffers/reflection.h
• Lines: 1-477

Signature

const Table *GetAnyRoot(const uint8_t *flatbuf);
int64_t GetAnyFieldI(const Table &table, const reflection::Field &field);
std::string GetAnyFieldS(const Table &table, const reflection::Field &field,
                          const reflection::Schema &schema);
void SetAnyFieldI(Table *table, const reflection::Field &field, int64_t val);

Import

#include "flatbuffers/reflection.h"

I/O Contract

Input	Output
FlatBuffer bytes + binary reflection schema (.bfbs)	Dynamic field access by name or index at runtime
Table reference + Field descriptor + new value	Mutated FlatBuffer field in-place

Usage Examples

#include "flatbuffers/reflection.h"
#include "flatbuffers/reflection_generated.h"

auto &schema = *reflection::GetSchema(schema_bfbs);
auto root_table = schema.root_table();
auto *field = root_table->fields()->LookupByKey("hp");

auto root = flatbuffers::GetAnyRoot(buffer);
int64_t hp = flatbuffers::GetAnyFieldI(*root, *field);

Related Pages

• Environment:Alibaba_MNN_CPU_Build_Environment