C++ Implementation Reference

See also: Streaming API

All C++ implementations keep single-file algorithm cores, but now depend on a shared streaming/buffer facade under algorithms/shared/cpp/include/compresskit/.

Compilation

g++ -std=c++17 -O2 -Wall -Wextra -o <binary> main.cpp

Recommended Flags

Flag	Purpose
-std=c++17	Enable C++17 features
-O2	Optimization level
-Wall -Wextra	Warnings
-fsanitize=address	AddressSanitizer (debug builds)
-fsanitize=undefined	UBSan (debug builds)

Huffman (algorithms/huffman/cpp/main.cpp)

Usage

./huffman_cpp encode input.bin output.huf
./huffman_cpp decode output.huf decoded.bin

Internal Structure

• BitWriter / BitReader — bit-level I/O classes
• Node — Huffman tree node with custom deleter
• compress_file() / decompress_file() — main encode/decode functions

File Format

Offset	Size	Field
0	4B	Magic: HFMN
4	4B	Frequency table size (always 257)
8	1028B	Frequency table (257 × uint32 LE)
1036+	Variable	Encoded bit stream

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Arithmetic (algorithms/arithmetic/cpp/main.cpp)

Usage

./arithmetic_cpp encode input.bin output.aenc
./arithmetic_cpp decode output.aenc decoded.bin

Key Classes

• ArithmeticEncoder — state machine with low, high, pendingBits
• ArithmeticDecoder — decoder with code initialization

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Range Coder (algorithms/range/cpp/main.cpp)

Usage

./rangecoder_cpp encode input.bin output.rcnc
./rangecoder_cpp decode output.rcnc decoded.bin

File Format

Offset	Size	Field
0	4B	Magic: RCNC
4	4B	Frequency table size
8	Variable	Frequency table
...	Variable	Byte stream (renormalized intervals)

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RLE (algorithms/rle/cpp/main.cpp)

Usage

./rle_cpp encode input.bin output.rle
./rle_cpp decode output.rle decoded.bin

File Format

Offset	Size	Field
0	4B	Magic: RLE\x00
4+	Variable	Repeated (count: uint32 LE, value: byte) pairs

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Common Patterns

Pattern	Description
Single-file core	Each algorithm core in one main.cpp
Shared dependencies	Uses common code from algorithms/shared/cpp/
Error handling	fprintf(stderr, ...) + exit(1)
Memory management	std::unique_ptr with custom deleters

Shared Streaming Facade

The streaming and buffer helpers live in:

• compresskit/result.hpp
• compresskit/encoder.hpp
• compresskit/buffer_api.hpp
• compresskit/algorithms.hpp

These headers provide a common Encoder / Decoder lifecycle and algorithm factories such as compresskit::make_huffman_encoder().