Rust API Reference : Honzo

The Rust API is the primary surface for Honzo. It is organized across two crates. Use honzo-core for no_std parsing. Use honzo-io for everything else.

honzo-core (no_std)

Zero-dependency

honzo-core has no dependencies. Use it in embedded contexts, kernels, and audit-critical paths where you cannot allocate.

Symbol	Signature	Returns	Notes
`HonzoParser::new`	`pub fn new(data: &[u8], version: u32)`	`Result<Self>`	Parse HEAD from byte slice. No alloc.
`parser.head`	`pub fn head(&self) -> &HonzoHead`	`&HonzoHead`	Pointer-cast to HEAD struct.
`parser.toc_entries`	`pub fn toc_entries(&self) -> &[TocEntry]`	`&[TocEntry]`	Pointer-cast to TOC array.
`parser.read_chunk`	`pub fn read_chunk(&self, entry: &TocEntry)`	`Result<&[u8]>`	Returns raw chunk bytes. No decompression.
`parser.extra_entries`	`pub fn extra_entries(&self) -> &[ExtraEntry]`	`&[ExtraEntry]`	EXTRA entry references.
`parser.read_extra`	`pub fn read_extra(&self, entry: &ExtraEntry)`	`Result<&[u8]>`	Raw extra entry bytes.
`parser.meta`	`pub fn meta(&self) -> &[u8]`	`&[u8]`	Raw META bytes (MessagePack).

honzo-io

Full featured crate with Builder, streaming reader, and compression.

Main types

Type	Purpose
`HonzoParser`	Zero-copy parser (re-exported from honzo-core)
`HonzoStream`	Pull-based streaming reader
`HonzoReader`	Reader with DRM decryption support
`Builder`	Programmatic file builder
`DrmConfig`	DRM configuration

Reader API

Symbol	Signature	Returns	Notes
`HonzoReader::new`	`pub fn new(data: &[u8], version: u32)`	`Self`	Create reader.
`reader.with_drm_key`	`pub fn with_drm_key(self, key: &[u8; 32])`	`Self`	Set X25519 private key for DRM.
`reader.parse`	`pub fn parse(&mut self)`	`Result<()>`	Parse file structure and unwrap DRM envelope.
`reader.head`	`pub fn head(&self) -> &HonzoHead`	`&HonzoHead`	File header.
`reader.toc_entries`	`pub fn toc_entries(&self) -> &[TocEntry]`	`&[TocEntry]`	Table of contents.
`reader.read_chunk`	`pub fn read_chunk(&self, entry: &TocEntry)`	`Result<Vec<u8>>`	Read and decompress a chunk. Decrypts if DRM key set.

Stream API

Symbol	Signature	Returns	Notes
`HonzoStream::open`	`pub fn open(file: File, version: u32)`	`Result<Self>`	Open from std::fs::File.
`stream.with_drm_key`	`pub fn with_drm_key(self, key: &[u8; 32])`	`Self`	Enable DRM decryption.
`stream.head`	`pub fn head(&self) -> &HonzoHead`	`&HonzoHead`	File header.
`stream.chapters`	`pub fn chapters(&mut self)`	`ChapterIter`	Iterator over chapter chunks.
`stream.chunk`	`pub fn chunk(&mut self, idx: usize)`	`Result<ChapterData>`	Read specific chunk by index.

Builder API

Symbol	Signature	Returns	Notes
`Builder::new`	`pub fn new()`	`Self`	New builder.
`builder.meta_title`	`pub fn meta_title(self, lang, title)`	`Self`	Set localized title.
`builder.meta_creator`	`pub fn meta_creator(self, lang, creator)`	`Self`	Set localized creator.
`builder.add_chapter`	`pub fn add_chapter(self, content, compression, markup)`	`Self`	Add a chapter chunk.
`builder.add_chunk`	`pub fn add_chunk(self, tag, data, compression, markup, cover, lang, font_embed, font_license)`	`Self`	Add any chunk type.
`builder.with_drm`	`pub fn with_drm(self, config: DrmConfig)`	`Self`	Enable DRM encryption.
`builder.finalize`	`pub fn finalize(self)`	`Result<Vec<u8>>`	Build the Honzo file bytes.

Crypto API

Symbol	Signature	Returns	Notes
`generate_cek`	`pub fn generate_cek()`	`[u8; 32]`	Random 256-bit CEK.
`generate_nonce`	`pub fn generate_nonce()`	`[u8; 12]`	Random 12-byte nonce.
`encrypt_content`	`pub fn encrypt_content(data, key)`	`Result<Vec<u8>>`	AES-256-GCM encrypt.
`decrypt_content`	`pub fn decrypt_content(data, key)`	`Result<Vec<u8>>`	AES-256-GCM decrypt.
`wrap_cek`	`pub fn wrap_cek(cek, recipient_pub)`	`Result<Vec<u8>>`	Wrap CEK for recipient.
`unwrap_cek`	`pub fn unwrap_cek(envelope, private_key)`	`Result<Vec<u8>>`	Unwrap CEK with private key.

DrmConfig API

Symbol	Signature	Returns	Notes
`DrmConfig::new`	`pub fn new()`	`Self`	New DRM config.
`config.encrypt_chunks`	`pub fn encrypt_chunks(self, indices)`	`Self`	Chunk IDs to encrypt.
`config.add_recipient`	`pub fn add_recipient(self, pub_key, id)`	`Self`	Add a recipient by X25519 public key.
`config.expiry`	`pub fn expiry(self, expiry)`	`Self`	Optional expiry timestamp.
`config.license_url`	`pub fn license_url(self, url)`	`Self`	Optional license URL.

Error model

All fallible operations return Result<T, HonzoError>. Error variants include:

Variant	Meaning
InvalidMagic	Not a Honzo file
InvalidVersion	Unsupported format version
InvalidChecksum	Integrity check failed
CompressionError	LZ4 decompression failure
DrmError	DRM-related failure. No key, bad envelope, and so on.
CryptoError	Encryption or decryption failure