crunch

a tool to compress and archive files. i built this to get hands-on with huffman coding and lz77. it's a standalone archiver that handles multi-file structures and verifies data integrity.

usage

you'll need rust and cargo.

compress a file

cargo run -- compress -i data.txt -a huffman (swap huffman for lz77 if you want dictionary-based compression)

decompress

cargo run -- decompress -i data.crunch -o ./extracted

archive a directory

cargo run -- archive -i src/ -o backup.crunch

see what's inside

cargo run -- list -i backup.crunch

frequency analysis

cargo run -- stats -i data.txt shows a histogram of byte frequencies in the terminal.

benchmark

cargo run -- bench -i data.txt compares crunch (huffman) against the standard zip implementation for size and speed.

internals

• huffman: uses canonical huffman to minimize tree overhead in the archive.
• lz77: sliding window implementation with a custom bit-stream format.
• metadata: uses a custom binary header with crc32 checksums for every file.
• bit-io: custom bit-level reader and writer for precise stream control.

testing

cargo test