.lzh file format of LHA (AKA LHarc) by Yoshizaki Haruyasu: Perl 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

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.

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

Lzh.pm

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

use strict;
use warnings;
use IO::KaitaiStruct 0.007_000;
use Encode;

########################################################################
package Lzh;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root || $self;;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{entries} = ();
    while (!$self->{_io}->is_eof()) {
        push @{$self->{entries}}, Lzh::Record->new($self->{_io}, $self, $self->{_root});
    }
}

sub entries {
    my ($self) = @_;
    return $self->{entries};
}

########################################################################
package Lzh::Record;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root || $self;;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{header_len} = $self->{_io}->read_u1();
    if ($self->header_len() > 0) {
        $self->{file_record} = Lzh::FileRecord->new($self->{_io}, $self, $self->{_root});
    }
}

sub header_len {
    my ($self) = @_;
    return $self->{header_len};
}

sub file_record {
    my ($self) = @_;
    return $self->{file_record};
}

########################################################################
package Lzh::FileRecord;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root || $self;;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{_raw_header} = $self->{_io}->read_bytes(($self->_parent()->header_len() - 1));
    my $io__raw_header = IO::KaitaiStruct::Stream->new($self->{_raw_header});
    $self->{header} = Lzh::Header->new($io__raw_header, $self, $self->{_root});
    if ($self->header()->header1()->lha_level() == 0) {
        $self->{file_uncompr_crc16} = $self->{_io}->read_u2le();
    }
    $self->{body} = $self->{_io}->read_bytes($self->header()->header1()->file_size_compr());
}

sub header {
    my ($self) = @_;
    return $self->{header};
}

sub file_uncompr_crc16 {
    my ($self) = @_;
    return $self->{file_uncompr_crc16};
}

sub body {
    my ($self) = @_;
    return $self->{body};
}

sub _raw_header {
    my ($self) = @_;
    return $self->{_raw_header};
}

########################################################################
package Lzh::Header;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root || $self;;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{header1} = Lzh::Header1->new($self->{_io}, $self, $self->{_root});
    if ($self->header1()->lha_level() == 0) {
        $self->{filename_len} = $self->{_io}->read_u1();
    }
    if ($self->header1()->lha_level() == 0) {
        $self->{filename} = Encode::decode("ASCII", $self->{_io}->read_bytes($self->filename_len()));
    }
    if ($self->header1()->lha_level() == 2) {
        $self->{file_uncompr_crc16} = $self->{_io}->read_u2le();
    }
    if ($self->header1()->lha_level() == 2) {
        $self->{os} = $self->{_io}->read_u1();
    }
    if ($self->header1()->lha_level() == 2) {
        $self->{ext_header_size} = $self->{_io}->read_u2le();
    }
}

sub header1 {
    my ($self) = @_;
    return $self->{header1};
}

sub filename_len {
    my ($self) = @_;
    return $self->{filename_len};
}

sub filename {
    my ($self) = @_;
    return $self->{filename};
}

sub file_uncompr_crc16 {
    my ($self) = @_;
    return $self->{file_uncompr_crc16};
}

sub os {
    my ($self) = @_;
    return $self->{os};
}

sub ext_header_size {
    my ($self) = @_;
    return $self->{ext_header_size};
}

########################################################################
package Lzh::Header1;

our @ISA = 'IO::KaitaiStruct::Struct';

sub from_file {
    my ($class, $filename) = @_;
    my $fd;

    open($fd, '<', $filename) or return undef;
    binmode($fd);
    return new($class, IO::KaitaiStruct::Stream->new($fd));
}

sub new {
    my ($class, $_io, $_parent, $_root) = @_;
    my $self = IO::KaitaiStruct::Struct->new($_io);

    bless $self, $class;
    $self->{_parent} = $_parent;
    $self->{_root} = $_root || $self;;

    $self->_read();

    return $self;
}

sub _read {
    my ($self) = @_;

    $self->{header_checksum} = $self->{_io}->read_u1();
    $self->{method_id} = Encode::decode("ASCII", $self->{_io}->read_bytes(5));
    $self->{file_size_compr} = $self->{_io}->read_u4le();
    $self->{file_size_uncompr} = $self->{_io}->read_u4le();
    $self->{file_timestamp} = $self->{_io}->read_u4le();
    $self->{attr} = $self->{_io}->read_u1();
    $self->{lha_level} = $self->{_io}->read_u1();
}

sub header_checksum {
    my ($self) = @_;
    return $self->{header_checksum};
}

sub method_id {
    my ($self) = @_;
    return $self->{method_id};
}

sub file_size_compr {
    my ($self) = @_;
    return $self->{file_size_compr};
}

sub file_size_uncompr {
    my ($self) = @_;
    return $self->{file_size_uncompr};
}

sub file_timestamp {
    my ($self) = @_;
    return $self->{file_timestamp};
}

sub attr {
    my ($self) = @_;
    return $self->{attr};
}

sub lha_level {
    my ($self) = @_;
    return $self->{lha_level};
}

1;