.lzh file format of LHA (AKA LHarc) by Yoshizaki Haruyasu: Go parsing library

LHA (LHarc, LZH) is a file format used by a popular freeware eponymous archiver, created in 1988 by Haruyasu Yoshizaki. Over the years, many ports and implementations were developed, sporting many extensions to original 1988 LZH.

File format is pretty simple and essentially consists of a stream of records.

Application

LHA (AKA LHarc) by Yoshizaki Haruyasu

File extension

lzh

KS implementation details

License: CC0-1.0

References

This page hosts a formal specification of .lzh file format of LHA (AKA LHarc) by Yoshizaki Haruyasu using Kaitai Struct. This specification can be automatically translated into a variety of programming languages to get a parsing library.

Go source code to parse .lzh file format of LHA (AKA LHarc) by Yoshizaki Haruyasu

lzh.go

// This is a generated file! Please edit source .ksy file and use kaitai-struct-compiler to rebuild

import (
	"github.com/kaitai-io/kaitai_struct_go_runtime/kaitai"
	"bytes"
)


/**
 * LHA (LHarc, LZH) is a file format used by a popular freeware
 * eponymous archiver, created in 1988 by Haruyasu Yoshizaki. Over the
 * years, many ports and implementations were developed, sporting many
 * extensions to original 1988 LZH.
 * 
 * File format is pretty simple and essentially consists of a stream of
 * records.
 */
type Lzh struct {
	Entries []*Lzh_Record
	_io *kaitai.Stream
	_root *Lzh
	_parent interface{}
}
func NewLzh() *Lzh {
	return &Lzh{
	}
}

func (this *Lzh) Read(io *kaitai.Stream, parent interface{}, root *Lzh) (err error) {
	this._io = io
	this._parent = parent
	this._root = root

	for i := 1;; i++ {
		tmp1, err := this._io.EOF()
		if err != nil {
			return err
		}
		if tmp1 {
			break
		}
		tmp2 := NewLzh_Record()
		err = tmp2.Read(this._io, this, this._root)
		if err != nil {
			return err
		}
		this.Entries = append(this.Entries, tmp2)
	}
	return err
}
type Lzh_Record struct {
	HeaderLen uint8
	FileRecord *Lzh_FileRecord
	_io *kaitai.Stream
	_root *Lzh
	_parent *Lzh
}
func NewLzh_Record() *Lzh_Record {
	return &Lzh_Record{
	}
}

func (this *Lzh_Record) Read(io *kaitai.Stream, parent *Lzh, root *Lzh) (err error) {
	this._io = io
	this._parent = parent
	this._root = root

	tmp3, err := this._io.ReadU1()
	if err != nil {
		return err
	}
	this.HeaderLen = tmp3
	if (this.HeaderLen > 0) {
		tmp4 := NewLzh_FileRecord()
		err = tmp4.Read(this._io, this, this._root)
		if err != nil {
			return err
		}
		this.FileRecord = tmp4
	}
	return err
}
type Lzh_FileRecord struct {
	Header *Lzh_Header
	FileUncomprCrc16 uint16
	Body []byte
	_io *kaitai.Stream
	_root *Lzh
	_parent *Lzh_Record
	_raw_Header []byte
}
func NewLzh_FileRecord() *Lzh_FileRecord {
	return &Lzh_FileRecord{
	}
}

func (this *Lzh_FileRecord) Read(io *kaitai.Stream, parent *Lzh_Record, root *Lzh) (err error) {
	this._io = io
	this._parent = parent
	this._root = root

	tmp5, err := this._io.ReadBytes(int((this._parent.HeaderLen - 1)))
	if err != nil {
		return err
	}
	tmp5 = tmp5
	this._raw_Header = tmp5
	_io__raw_Header := kaitai.NewStream(bytes.NewReader(this._raw_Header))
	tmp6 := NewLzh_Header()
	err = tmp6.Read(_io__raw_Header, this, this._root)
	if err != nil {
		return err
	}
	this.Header = tmp6
	if (this.Header.Header1.LhaLevel == 0) {
		tmp7, err := this._io.ReadU2le()
		if err != nil {
			return err
		}
		this.FileUncomprCrc16 = uint16(tmp7)
	}
	tmp8, err := this._io.ReadBytes(int(this.Header.Header1.FileSizeCompr))
	if err != nil {
		return err
	}
	tmp8 = tmp8
	this.Body = tmp8
	return err
}
type Lzh_Header struct {
	Header1 *Lzh_Header1
	FilenameLen uint8
	Filename string
	FileUncomprCrc16 uint16
	Os uint8
	ExtHeaderSize uint16
	_io *kaitai.Stream
	_root *Lzh
	_parent *Lzh_FileRecord
}
func NewLzh_Header() *Lzh_Header {
	return &Lzh_Header{
	}
}

func (this *Lzh_Header) Read(io *kaitai.Stream, parent *Lzh_FileRecord, root *Lzh) (err error) {
	this._io = io
	this._parent = parent
	this._root = root

	tmp9 := NewLzh_Header1()
	err = tmp9.Read(this._io, this, this._root)
	if err != nil {
		return err
	}
	this.Header1 = tmp9
	if (this.Header1.LhaLevel == 0) {
		tmp10, err := this._io.ReadU1()
		if err != nil {
			return err
		}
		this.FilenameLen = tmp10
	}
	if (this.Header1.LhaLevel == 0) {
		tmp11, err := this._io.ReadBytes(int(this.FilenameLen))
		if err != nil {
			return err
		}
		tmp11 = tmp11
		this.Filename = string(tmp11)
	}
	if (this.Header1.LhaLevel == 2) {
		tmp12, err := this._io.ReadU2le()
		if err != nil {
			return err
		}
		this.FileUncomprCrc16 = uint16(tmp12)
	}
	if (this.Header1.LhaLevel == 2) {
		tmp13, err := this._io.ReadU1()
		if err != nil {
			return err
		}
		this.Os = tmp13
	}
	if (this.Header1.LhaLevel == 2) {
		tmp14, err := this._io.ReadU2le()
		if err != nil {
			return err
		}
		this.ExtHeaderSize = uint16(tmp14)
	}
	return err
}

/**
 * Level-neutral header, same for all LHA levels. Subsequent fields order and meaning varies, based on LHA level specified in this header.
 */
type Lzh_Header1 struct {
	HeaderChecksum uint8
	MethodId string
	FileSizeCompr uint32
	FileSizeUncompr uint32
	FileTimestamp *DosDatetime
	Attr uint8
	LhaLevel uint8
	_io *kaitai.Stream
	_root *Lzh
	_parent *Lzh_Header
	_raw_FileTimestamp []byte
}
func NewLzh_Header1() *Lzh_Header1 {
	return &Lzh_Header1{
	}
}

func (this *Lzh_Header1) Read(io *kaitai.Stream, parent *Lzh_Header, root *Lzh) (err error) {
	this._io = io
	this._parent = parent
	this._root = root

	tmp15, err := this._io.ReadU1()
	if err != nil {
		return err
	}
	this.HeaderChecksum = tmp15
	tmp16, err := this._io.ReadBytes(int(5))
	if err != nil {
		return err
	}
	tmp16 = tmp16
	this.MethodId = string(tmp16)
	tmp17, err := this._io.ReadU4le()
	if err != nil {
		return err
	}
	this.FileSizeCompr = uint32(tmp17)
	tmp18, err := this._io.ReadU4le()
	if err != nil {
		return err
	}
	this.FileSizeUncompr = uint32(tmp18)
	tmp19, err := this._io.ReadBytes(int(4))
	if err != nil {
		return err
	}
	tmp19 = tmp19
	this._raw_FileTimestamp = tmp19
	_io__raw_FileTimestamp := kaitai.NewStream(bytes.NewReader(this._raw_FileTimestamp))
	tmp20 := NewDosDatetime()
	err = tmp20.Read(_io__raw_FileTimestamp, this, nil)
	if err != nil {
		return err
	}
	this.FileTimestamp = tmp20
	tmp21, err := this._io.ReadU1()
	if err != nil {
		return err
	}
	this.Attr = tmp21
	tmp22, err := this._io.ReadU1()
	if err != nil {
		return err
	}
	this.LhaLevel = tmp22
	return err
}

/**
 * Compressed file size
 */

/**
 * Uncompressed file size
 */

/**
 * Original file date/time
 */

/**
 * File or directory attribute
 */