Better - Rechunk000pak

// Build chunk assignment let mut chunks: Vec<Chunk> = Vec::new(); for entry in old_index.entries let file_data = read_file_data(source_pak, entry.offset, entry.size)?; let compressed = compress_chunk(&file_data, compression_type)?; let chunk = Chunk::new(compressed, entry.hash); chunks.push(chunk);

// Write chunks in parallel (chunks independent) let chunk_offsets = write_chunks_parallel(&mut new_writer, &chunks)?; rechunk000pak better

Ok(()) | Bad rechunking | Better rechunking | |------------------------------------|---------------------------------------------| | Ignores alignment | Aligns to 4K/512B | | Single thread | Parallel chunk compression + I/O | | No checksums | SHA-256 or XXH3 per chunk | | Overwrites source in-place | Writes new file, atomic rename | | Uncompressed only | Adaptive compression (Zstd/LZ4) | | No progress indicator | ETA + resumable via chunk list checkpoint | | Breaks after partial write | Transactional write + recovery journal | 7. Benchmark: Rechunking a 10 GB Game PAK Test system: Ryzen 5950X, 64 GB RAM, NVMe SSD. // Build chunk assignment let mut chunks: Vec&lt;Chunk&gt;

Better: compress each chunk independently with Zstd with dictionary training across all chunks of same file type. Align chunk start offsets to 4096 bytes. Many tools ignore this → extra read amplification. Align chunk start offsets to 4096 bytes

// Validate validate_rechunk(target_pak, &old_index)?;