Fastahack is a small application for indexing and extracting sequences and subsequences from FASTA files. The included Fasta.cpp library provides a FASTA reader and indexer that can be embedded into applications which would benefit from directly reading subsequences from FASTA files. The library automatically handles index file generation and use.

Features: * FASTA index (.fai) generation for FASTA files * Sequence extraction * Subsequence extraction * Sequence statistics (currently only entropy is provided)

Sequence and subsequence extraction use fseek64 to provide fastest-possible extraction without RAM-intensive file loading operations. This makes fastahack a useful tool for bioinformaticists who need to quickly extract many subsequences from a reference FASTA sequence.