Subhrajyoti Sahoo
Subhrajyoti Sahoo
aka
@subhra8640

shipped

CZP (Custom ZIP)

Custom DEFLATE-like compression engine & multi-file archiver built from scratch in C++17.

C++C++17LZ77HuffmanAlgorithms
GitHub ↗

Overview

CZP is a complete compression and archival tool built from first principles in C++ on Windows with zero external compression libraries.

Core Pipeline & Technology

  • BitStream: Low-level bit manipulation engine for bit-aligned reading and writing (1–32 bits).
  • LZ77 Compression: Dictionary-based pattern matching with a 32KB sliding window, 16-bit hash table, and chain traversal.
  • Huffman Coding: Canonical prefix coding with code length limitations (15-bit max).
  • DEFLATE Integration: Two-stage compression pipeline pairing LZ77 match tokens with Huffman entropy encoding.
  • CRC32 Checksums: Built-in data integrity calculation and verification for archive headers and contents.

Archive Format & CLI Tool

  • Custom .czp binary format with Global Header (CZP!), Local File Headers (FILE), and Central Directory metadata.
  • Support for STORE (uncompressed) and DEFLATE compression modes with directory structure preservation.
  • Full-featured CLI for compression, extraction, archive content listing, and integrity verification.

64 automated unit tests covering BitStream, Huffman coding, LZ77 dictionary search, DEFLATE pipeline, and archive serialization.

Lessons

Building compression algorithms from scratch demystifies binary formats, bit packing, and dictionary sliding windows.