package Games::NES::ROM;
use Moose;
use Module::Runtime ();
use Try::Tiny;
use FileHandle;
our $VERSION = '0.08';
has 'filename' => ( is => 'rw' );
has 'filehandle' => ( is => 'rw', isa => 'FileHandle', lazy_build => 1 );
has 'id' => ( is => 'ro' );
has 'title' => ( is => 'rw' );
has 'prg_banks' => ( is => 'rw', isa => 'ArrayRef', default => sub { [] } );
has 'chr_banks' => ( is => 'rw', isa => 'ArrayRef', default => sub { [] } );
has 'has_sram' => ( is => 'rw', isa => 'Bool', default => 0 );
has 'mirroring' => ( is => 'rw', isa => 'Int', default => 0 );
has 'mapper' => ( is => 'rw' );
sub _build_filehandle {
my $self = shift;
my $file = $self->filename;
my $fh = FileHandle->new( $file, '<' );
die "Unable to open ${file}: $!" unless defined $fh;
binmode( $fh );
return $fh;
}
__PACKAGE__->meta->make_immutable;
sub load {
my( $class, $file ) = @_;
for( qw( INES UNIF ) ) {
my $class = 'Games::NES::ROM::Format::' . $_;
Module::Runtime::require_module( $class );
my $rom = try {
$class->new( filename => $file );
};
return $rom if $rom;
}
die "${file} is not an NES rom";
}
sub prg_count {
return scalar @{ shift->prg_banks };
}
sub chr_count {
return scalar @{ shift->chr_banks };
}
sub sha1 {
my $self = shift;
require Digest::SHA1;
return Digest::SHA1::sha1_hex( @{ $self->prg_banks }, @{ $self->chr_banks } );
}
sub crc {
my $self = shift;
require Digest::CRC;
return Digest::CRC::crc32_hex( join( '', @{ $self->prg_banks }, @{ $self->chr_banks } ) );
}
sub sprite {
my( $self, $chr, $offset ) = @_;
die 'invalid CHR bank' if $chr > $self->chr_count - 1 or $chr < 0;
die 'invalid sprite index' if $offset > 512 or $offset < 0;
my $bank = $self->chr_banks->[ $chr ];
my $start = 16 * $offset;
my @channel_a = unpack( 'C*', substr( $bank, $start, 8 ) );
my @channel_b = unpack( 'C*', substr( $bank, $start + 8, 8 ) );
my $composite = '';
for my $i ( 0..7 ) {
for my $j ( reverse 0..7 ) {
$composite .= pack( 'C', $self->_combine_bits( $channel_a[ $i ], $channel_b[ $i ], $j ) );
}
}
return $composite;
}
sub _combine_bits {
my $self = shift;
my( $chan_a, $chan_b, $offset ) = @_;
return ( ( $chan_a >> $offset ) & 1 ) | ( ( ( $chan_b >> $offset ) & 1 ) << 1 );
}
1;
__END__
=head1 NAME
Games::NES::ROM - View information about an NES game from a ROM file
=head1 SYNOPSIS
use Games::NES::ROM;
# Read in the ROM without having to know its format
my $rom = Games::NES::ROM->load( 'file.nes' );
# Specifically read in an iNES file
$rom = Games::NES::ROM::INES->new( filename => 'file.nes' );
# Access the details
print 'PRG Banks: ', $rom->prg_count, "\n";
print 'CHR Banks: ', $rom->prg_count, "\n";
# etc...
# View the SHA-1 & CRC checksums
print 'SHA1: ', $rom->sha1, "\n";
print ' CRC: ', $rom->crc, "\n";
=head1 DESCRIPTION
This module loads the details of an NES rom file. It is primarily meant to be
used a base class for more specific file formats. Those formats include:
=over 4
=item * L<Universal NES Image File (UNIF)|Games::NES::ROM::Format::UNIF>
=item * L<iNES|Games::NES::ROM::Format::INES>
=back
=head1 INSTALLATION
perl Makefile.PL
make
make test
make install
=head1 METHODS
=head2 load( $filename )
Attemps to read the ROM structure into memory using all available file
formats until success.
=head2 prg_count( )
Returns the number of PRG banks for this ROM.
=head2 chr_count( )
Returns the number of CHR banks for this ROM.
=head2 sha1( )
Returns the SHA-1 checksum for the PRG and CHR data.
=head2 crc( )
Returns the CRC checksum for the PRG and CHR data.
=head2 sprite( $chr_bank, $index )
Returns the raw (composite) sprite in the specified
CHR bank at the specified array index.
=head1 BASE ATTRIBUTES
The following base attributes are available for all file formats:
=over 4
=item * filename - The filename from which data was loaded
=item * id - A string found at the beginning of a file to identify the file format
=item * title - The game's title, if available
=item * prg_banks - An arrayref of PRG bank data
=item * chr_banks - An arrayref of CHR bank data
=item * has_sram - Boolean value to determine if the ROM is battery backed
=item * mapper - A value indicating what memory mapper to use with the ROM
=item * mirroring - A value indicating what time of mirroring is used in the ROM
=back
=head2 NOTES
=over 4
=item * mapper - iNES uses integer IDs, UNIF uses string IDs
=item * mirroring - An integer ID, using the UNIF list as a basis
=back
Each file format will have an extended set of attributes specific to its data
structure. Please consult their documentation for more information.
=head1 SEE ALSO
=over 4
=item * L<Games::NES::ROM::Format::INES>
=item * L<Games::NES::ROM::Format::UNIF>
=back
=head1 AUTHOR
Brian Cassidy E<lt>bricas@cpan.orgE<gt>
=head1 COPYRIGHT AND LICENSE
Copyright 2007-2013 by Brian Cassidy
This library is free software; you can redistribute it and/or modify
it under the same terms as Perl itself.
=cut