Implementation:Alibaba MNN Protobuf Generated Table Driven Lite H

Knowledge Sources	Alibaba_MNN Protocol Buffers
Domains	Serialization, Parsing
Last Updated	2026-02-10 12:00 GMT

Overview

Lite version of the table-driven parsing header, providing the core parsing logic without full protobuf runtime dependencies.

Description

This header contains the actual implementation of table-driven parsing routines in the protobuf-lite variant, which avoids dependencies on reflection, descriptors, and other heavyweight features. It includes template specializations for parsing each wire type (varint, fixed32, fixed64, length-delimited, groups) and dispatching to the correct field handler based on the parse table metadata. MNN vendors this file because it provides the performance-critical fast path for deserializing TensorFlow and Caffe model protobuf data, enabling efficient parsing of large model files with minimal overhead.

Usage

Vendored dependency used internally by MNN for parsing protobuf-based model formats (TensorFlow, Caffe). Not directly imported by end users.

Code Reference

Source Location

• Repository: Alibaba_MNN
• File: 3rd_party/protobuf/src/google/protobuf/generated_message_table_driven_lite.h
• Lines: 1-874

Signature

namespace google {
namespace protobuf {
namespace internal {
template <typename Entry> bool ParseField(io::CodedInputStream* input, const ParseTable& table, MessageLite* msg);
bool MergePartialFromCodedStreamLite(MessageLite* msg, const ParseTable& table, io::CodedInputStream* input);
template <> bool HandleString<false>(io::CodedInputStream* input, MessageLite* msg, Arena* arena, uint32 offset);
}  // namespace internal
}  // namespace protobuf
}  // namespace google

Import

#include "3rd_party/protobuf/src/google/protobuf/generated_message_table_driven_lite.h"

I/O Contract

Inputs

Name	Type	Required	Description
input	io::CodedInputStream*	Yes	Coded input stream wrapping serialized protobuf bytes
table	const ParseTable&	Yes	Compiled parse table with field metadata for table-driven dispatch
msg	MessageLite*	Yes	Target message object to populate with parsed data

Outputs

Name	Type	Description
success	bool	Whether parsing completed without errors
msg	MessageLite*	Message with fields populated from the wire-format input

Usage Examples

// MNN internal usage (generated lite message parsing)
io::CodedInputStream input(raw_data, size);
static const internal::ParseTable kTable = { ... };
bool ok = internal::MergePartialFromCodedStreamLite(
    this, kTable, &input);

Related Pages

• Environment:Alibaba_MNN_CPU_Build_Environment