#------------------------------------------------------------------------------
# File:         APE.pm
#
# Description:  Read Monkey's Audio meta information
#
# Revisions:    11/13/2006 - P. Harvey Created
#
# References:   1) http://www.monkeysaudio.com/
#               2) http://www.personal.uni-jena.de/~pfk/mpp/sv8/apetag.html
#------------------------------------------------------------------------------

package Image::ExifTool::APE;

use strict;
use vars qw($VERSION);
use Image::ExifTool qw(:DataAccess :Utils);

$VERSION = '1.02';

# APE metadata blocks
%Image::ExifTool::APE::Main = (
    GROUPS => { 2 => 'Audio' },
    NOTES => q{
        Tags found in Monkey's Audio (APE) information.  Only a few common tags are
        listed below, but ExifTool will extract any tag found.  ExifTool supports
        APEv1 and APEv2 tags, as well as ID3 information in APE files, and will also
        read APE metadata from MP3 files.
    },
    Album   => { },
    Artist  => { },
    Genre   => { },
    Title   => { },
    Track   => { },
    Year    => { },
    'Tool Version' => { Name => 'ToolVersion' },
    'Tool Name'    => { Name => 'ToolName' },
);

# APE MAC header version 3.97 or earlier
%Image::ExifTool::APE::OldHeader = (
    PROCESS_PROC => \&Image::ExifTool::ProcessBinaryData,
    GROUPS => { 1 => 'MAC', 2 => 'Audio' },
    FORMAT => 'int16u',
    NOTES => 'APE MAC audio header for version 3.97 or earlier.',
    0 => {
        Name => 'APEVersion',
        ValueConv => '$val / 1000',
    },
    1 => 'CompressionLevel',
  # 2 => 'FormatFlags',
    3 => 'Channels',
    4 => { Name => 'SampleRate', Format => 'int32u' },
  # 6 => { Name => 'HeaderBytes', Format => 'int32u' }, # WAV header bytes
  # 8 => { Name => 'TerminatingBytes', Format => 'int32u' },
    10 => { Name => 'TotalFrames', Format => 'int32u' },
    12 => { Name => 'FinalFrameBlocks', Format => 'int32u' },
);

# APE MAC header version 3.98 or later
%Image::ExifTool::APE::NewHeader = (
    PROCESS_PROC => \&Image::ExifTool::ProcessBinaryData,
    GROUPS => { 1 => 'MAC', 2 => 'Audio' },
    FORMAT => 'int16u',
    NOTES => 'APE MAC audio header for version 3.98 or later.',
    0 => 'CompressionLevel',
  # 1 => 'FormatFlags',
    2 => { Name => 'BlocksPerFrame',   Format => 'int32u' },
    4 => { Name => 'FinalFrameBlocks', Format => 'int32u' },
    6 => { Name => 'TotalFrames',      Format => 'int32u' },
    8 => 'BitsPerSample',
    9 => 'Channels',
    10 => { Name => 'SampleRate',      Format => 'int32u' },
);

#------------------------------------------------------------------------------
# Make tag info hash for specified tag
# Inputs: 0) tag name, 1) tag table ref
# - must only call if tag doesn't exist
sub MakeTag($$)
{
    my ($tag, $tagTablePtr) = @_;
    my $name = ucfirst(lc($tag));
    # remove invalid characters in tag name and capitalize following letters
    $name =~ s/[^\w-]+(.?)/\U$1/sg;
    $name =~ s/([a-z0-9])_([a-z])/$1\U$2/g;
    AddTagToTable($tagTablePtr, $tag, { Name => $name });
}

#------------------------------------------------------------------------------
# Extract information from an APE file
# Inputs: 0) ExifTool object reference, 1) dirInfo reference
# - Just looks for APE trailer if FileType is already set
# Returns: 1 on success, 0 if this wasn't a valid APE file
sub ProcessAPE($$)
{
    my ($exifTool, $dirInfo) = @_;

    # must first check for leading/trailing ID3 information
    unless ($exifTool->{DoneID3}) {
        require Image::ExifTool::ID3;
        Image::ExifTool::ID3::ProcessID3($exifTool, $dirInfo) and return 1;
    }
    my $raf = $$dirInfo{RAF};
    my $verbose = $exifTool->Options('Verbose');
    my ($buff, $i, $header, $tagTablePtr, $dataPos, $oldIndent);

    $exifTool->{DoneAPE} = 1;

    # check APE signature and process audio information
    # unless this is some other type of file
    unless ($exifTool->{VALUE}->{FileType}) {
        $raf->Read($buff, 32) == 32 or return 0;
        $buff =~ /^(MAC |APETAGEX)/ or return 0;
        $exifTool->SetFileType();
        SetByteOrder('II');

        if ($buff =~ /^APETAGEX/) {
            # we already read the APE header
            $header = 1;
        } else {
            # process the MAC header
            my $vers = Get16u(\$buff, 4);
            my $table;
            if ($vers <= 3970) {
                $buff = substr($buff, 4);
                $table = GetTagTable('Image::ExifTool::APE::OldHeader');
            } else {
                my $dlen = Get32u(\$buff, 8);
                my $hlen = Get32u(\$buff, 12);
                unless ($dlen & 0x80000000 or $hlen & 0x80000000) {
                    if ($raf->Seek($dlen, 0) and $raf->Read($buff, $hlen) == $hlen) {
                        $table = GetTagTable('Image::ExifTool::APE::NewHeader');
                    }
                }
            }
            $exifTool->ProcessDirectory( { DataPt => \$buff }, $table) if $table;
        }
    }
    # look for APE trailer unless we already found an APE header
    unless ($header) {
        # look for the APE trailer footer...
        my $footPos = -32;
        # (...but before the ID3v1 trailer if it exists)
        $footPos -= 128 if $exifTool->{DoneID3} == 2;
        $raf->Seek($footPos, 2)     or return 1;
        $raf->Read($buff, 32) == 32 or return 1;
        $buff =~ /^APETAGEX/        or return 1;
        SetByteOrder('II');
    }
#
# Read the APE data (we have just read the APE header or footer into $buff)
#
    my ($version, $size, $count, $flags) = unpack('x8V4', $buff);
    $version /= 1000;
    $size -= 32;    # get size of data only
    if (($size & 0x80000000) == 0 and
        ($header or $raf->Seek(-$size-32, 1)) and
        $raf->Read($buff, $size) == $size)
    {
        if ($verbose) {
            $oldIndent = $$exifTool{INDENT};
            $$exifTool{INDENT} .= '| ';
            $exifTool->VerboseDir("APEv$version", $count, $size);
            $exifTool->VerboseDump(\$buff, DataPos => $raf->Tell() - $size);
        }
        $tagTablePtr = GetTagTable('Image::ExifTool::APE::Main');
        $dataPos = $raf->Tell() - $size;
    } else {
        $count = -1;
    }
#
# Process the APE tags
#
    my $pos = 0;
    for ($i=0; $i<$count; ++$i) {
        # read next APE tag
        last if $pos + 8 > $size;
        my $len = Get32u(\$buff, $pos);
        my $flags = Get32u(\$buff, $pos + 4);
        pos($buff) = $pos + 8;
        last unless $buff =~ /\G(.*?)\0/sg;
        my $tag = $1;
        # avoid conflicts with our special table entries
        $tag .= '.' if $Image::ExifTool::specialTags{$tag};
        $pos = pos($buff);
        last if $pos + $len > $size;
        my $val = substr($buff, $pos, $len);
        MakeTag($tag, $tagTablePtr) unless $$tagTablePtr{$tag};
        # handle binary-value tags
        if (($flags & 0x06) == 0x02) {
            my $buf2 = $val;
            $val = \$buf2;
            # extract cover art description separately (hackitty hack)
            if ($tag =~ /^Cover Art/) {
                $buf2 =~ s/^([\x20-\x7f]*)\0//;
                if ($1) {
                    my $t = "$tag Desc";
                    my $v = $1;
                    MakeTag($t, $tagTablePtr) unless $$tagTablePtr{$t};
                    $exifTool->HandleTag($tagTablePtr, $t, $v);
                }
            }
        }
        $exifTool->HandleTag($tagTablePtr, $tag, $val,
            Index => $i,
            DataPt => \$buff,
            DataPos => $dataPos,
            Start => $pos,
            Size => $len,
        );
        $pos += $len;
    }
    $i == $count or $exifTool->Warn('Bad APE trailer');
    $$exifTool{INDENT} = $oldIndent if defined $oldIndent;
    return 1;
}

1;  # end

__END__

=head1 NAME

Image::ExifTool::APE - Read Monkey's Audio meta information

=head1 SYNOPSIS

This module is used by Image::ExifTool

=head1 DESCRIPTION

This module contains definitions required by Image::ExifTool to extract meta
information from Monkey's Audio (APE) audio files.

=head1 BUGS

Currently doesn't parse MAC header unless it is at the start of the file.

=head1 AUTHOR

Copyright 2003-2013, Phil Harvey (phil at owl.phy.queensu.ca)

This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.

=head1 REFERENCES

=over 4

=item L<http://www.monkeysaudio.com/>

=item L<http://www.personal.uni-jena.de/~pfk/mpp/sv8/apetag.html>

=back

=head1 SEE ALSO

L<Image::ExifTool::TagNames/APE Tags>,
L<Image::ExifTool(3pm)|Image::ExifTool>

=cut

