tec::NdCompress Class Reference

Compression wrapper for NetData objects with pluggable backends. More...

#include <tec_nd_compress.hpp>

Public Member Functions
	NdCompress ()
	Default constructor — uses library-wide default compression settings.
	NdCompress (int _type, int _level=CompressionParams::kDefaultCompressionLevel, size_t _min_size=CompressionParams::kMinSize)
	Constructs compressor with explicit settings.
virtual Status	compress (NetData &nd) const
	Compresses the payload of a NetData object in-place (if configured)
virtual Status	uncompress (NetData &nd) const
	Decompresses the payload of a NetData object in-place (if compressed)

Protected Attributes
int	type_
	Compression algorithm identifier (from CompressionParams)
int	level_
	Compression level (meaning depends on backend — usually [1..9] for Zlib)
size_t	min_size_
	Minimum payload size (in bytes) below which compression is skipped.

Detailed Description

Compression wrapper for NetData objects with pluggable backends.

Currently supports Zlib (deflate) when _TEC_USE_ZLIB / ZLIB_VERSION is defined. Designed to be used as a strategy object — either as a member or passed by const reference.

Main features:

• Configurable compression type, level, and minimum size threshold
• In-place modification of NetData (moves internal buffer when compression occurs)
• Skips compression for small payloads (controlled by min_size_)
• Sets appropriate fields in NetData::header (compression type, level, uncompressed size)

Note

All public methods are const — the object is immutable after construction.

Currently only Zlib is implemented; other algorithms can be added by extending the compress() / uncompress() dispatch logic.

Basic usage examples

// 1. Zlib (usually Zlib or no-op depending on build)
NdCompress compressor(CompressionParams::kCompressionZlib);
NetData msg = ...;           // filled message
compressor.compress(msg);    // may compress in-place
 
// Later on receiver side
compressor.uncompress(msg);  // restores original if was compressed
 
// 2. Explicit Zlib with custom level
NdCompress fast_compressor(
    CompressionParams::kCompressionZlib,
    3,                           // fast compression
    512                          // don't compress < 512 bytes
);
 
NetData large_payload = create_large_payload();
auto st = fast_compressor.compress(large_payload);
if (st) {
    send_over_network(large_payload);
}

Constructor & Destructor Documentation

NdCompress() [1/2]

tec::NdCompress::NdCompress ( )

inline

Default constructor — uses library-wide default compression settings.

Initializes with:

• type = CompressionParams::kDefaultCompression
• level = CompressionParams::kDefaultCompressionLevel
• min_size = CompressionParams::kMinSize

NdCompress compressor;  // most common usage

NdCompress() [2/2]

tec::NdCompress::NdCompress ( int  _type, int  _level = CompressionParams::kDefaultCompressionLevel, size_t  _min_size = CompressionParams::kMinSize  )

inlineexplicit

Constructs compressor with explicit settings.

Parameters

_type	Compression algorithm (e.g. CompressionParams::kCompressionZlib)
_level	Compression level (backend-specific; default = library default)
_min_size	Smallest payload size worth compressing (default = library minimum)

// Aggressive compression for archival/large messages
NdCompress archiver(CompressionParams::kCompressionZlib, 9, 1024);
 
// Very fast compression, skip tiny messages
NdCompress low_latency(CompressionParams::kCompressionZlib, 1, 256);

Member Function Documentation

compress()

virtual Status tec::NdCompress::compress ( NetData &  nd ) const

inlinevirtual

Compresses the payload of a NetData object in-place (if configured)

Parameters

nd	Network data object to compress (modified in-place on success)

Returns

Status::OK on success, error otherwise

Behavior:

• If payload size < min_size_, sets compression = kNoCompression and returns
• Otherwise delegates to backend-specific implementation (currently only zlib)
• On success: updates header fields (compression, compression_level, size_uncompressed)
• On failure: nd remains unchanged

NdCompress compressor(CompressionParams::kCompressionZlib, 6);
NetData frame = build_video_frame();
 
Status st = compressor.compress(frame);
if (!st) {
    LOG(ERROR) << "Compression failed: " << st.message();
    return;
}
 
// frame is now potentially smaller + header updated
network.send(frame);

uncompress()

virtual Status tec::NdCompress::uncompress ( NetData &  nd ) const

inlinevirtual

Decompresses the payload of a NetData object in-place (if compressed)

Parameters

nd	Network data object to decompress (modified in-place on success)

Returns

Status::OK on success, error otherwise

Behavior:

• If header indicates kNoCompression → returns immediately (no-op)
• Otherwise delegates to backend-specific decompressor
• On success: clears size_uncompressed and updates size
• On failure: nd remains unchanged

// Receiver side
NdCompress compressor;  // same settings as sender (or just default)
NetData received;
network.receive(received);
 
Status st = compressor.uncompress(received);
if (!st) {
    LOG(ERROR) << "Decompression failed: " << st.message();
    return;
}
 
// received.payload() now contains original uncompressed data
process_message(received);

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The documentation for this class was generated from the following file:

• net/tec_nd_compress.hpp