    001
    002package ibxm;
    003
    004import java.io.*;
    005
    006public class FastTracker2 {
    007    public static boolean is_xm( byte[] header_60_bytes ) {
    008        String xm_identifier;
    009        xm_identifier = ascii_text( header_60_bytes, 0, 17 );
    010        return xm_identifier.equals( "Extended Module: " );
    011    }
    012
    013    public static Module load_xm( byte[] header_60_bytes, DataInput data_input ) throws IOException {
    014        int xm_version, song_header_length, sequence_length;
    015        int num_channels, num_patterns, num_instruments, xm_flags, idx;
    016        byte[] structure_header, song_header;
    017        boolean delta_env;
    018        String tracker_name;
    019        Instrument instrument;
    020        Module module;
    021        if( !is_xm( header_60_bytes ) ) {
    022            throw new IllegalArgumentException( "Not an XM file!" );
    023        }
    024        xm_version = unsigned_short_le( header_60_bytes, 58 );
    025        if( xm_version != 0x0104 ) {
    026            throw new IllegalArgumentException( "Sorry, XM version " + xm_version + " is not supported!" );
    027        }
    028        module = new Module();
    029        module.song_title = ascii_text( header_60_bytes, 17, 20 );
    030        tracker_name = ascii_text( header_60_bytes, 38, 20 );
    031        delta_env = tracker_name.startsWith( "DigiBooster Pro" );
    032        structure_header = new byte[ 4 ];
    033        data_input.readFully( structure_header );
    034        song_header_length = int_le( structure_header, 0 );
    035        song_header = new byte[ song_header_length ];
    036        data_input.readFully( song_header, 4, song_header_length - 4 );
    037        sequence_length = unsigned_short_le( song_header, 4 );
    038        module.restart_sequence_index = unsigned_short_le( song_header, 6 );
    039        num_channels = unsigned_short_le( song_header, 8 );
    040        num_patterns = unsigned_short_le( song_header, 10 );
    041        num_instruments = unsigned_short_le( song_header, 12 );
    042        xm_flags = unsigned_short_le( song_header, 14 );
    043        module.linear_periods = ( xm_flags & 0x1 ) == 0x1;
    044        module.global_volume = 64;
    045        module.channel_gain = IBXM.FP_ONE * 3 / 8;
    046        module.default_speed = unsigned_short_le( song_header, 16 );
    047        module.default_tempo = unsigned_short_le( song_header, 18 );
    048        module.set_num_channels( num_channels );
    049        for( idx = 0; idx < num_channels; idx++ ) {
    050            module.set_initial_panning( idx, 128 );
    051        }
    052        module.set_sequence_length( sequence_length );
    053        for( idx = 0; idx < sequence_length; idx++ ) {
    054            module.set_sequence( idx, song_header[ 20 + idx ] & 0xFF );
    055        }
    056        module.set_num_patterns( num_patterns );
    057        for( idx = 0; idx < num_patterns; idx++ ) {
    058            module.set_pattern( idx, read_xm_pattern( data_input, num_channels ) );
    059        }
    060        module.set_num_instruments( num_instruments );
    061        for( idx = 1; idx <= num_instruments; idx++ ) {
    062            try {
    063                instrument = read_xm_instrument( data_input, delta_env );
    064                module.set_instrument( idx, instrument );
    065            } catch( EOFException e ) {
    066                System.out.println( "Instrument " + idx + " is missing!" );
    067            }
    068        }
    069        return module;
    070    }
    071
    072    private static Pattern read_xm_pattern( DataInput data_input, int num_channels ) throws IOException {
    073        int pattern_header_length, packing_type, num_rows, pattern_data_length;
    074        byte[] structure_header, pattern_header, pattern_data;
    075        Pattern pattern;
    076        structure_header = new byte[ 4 ];
    077        data_input.readFully( structure_header );
    078        pattern_header_length = int_le( structure_header, 0 );
    079        pattern_header = new byte[ pattern_header_length ];
    080        data_input.readFully( pattern_header, 4, pattern_header_length - 4 );
    081        packing_type = pattern_header[ 4 ];
    082        if( packing_type != 0 ) {
    083            throw new IllegalArgumentException( "Pattern packing type " + packing_type + " is not supported!" );
    084        }
    085        pattern = new Pattern();
    086        pattern.num_rows = unsigned_short_le( pattern_header, 5 );
    087        pattern_data_length = unsigned_short_le( pattern_header, 7 );
    088        pattern_data = new byte[ pattern_data_length ];
    089        data_input.readFully( pattern_data );
    090        pattern.set_pattern_data( pattern_data );
    091        return pattern;
    092    }
    093
    094    private static Instrument read_xm_instrument( DataInput data_input, boolean delta_env ) throws IOException {
    095        int instrument_header_length, num_samples, idx;
    096        int env_tick, env_ampl, env_num_points, flags;
    097        byte[] structure_header, instrument_header, sample_headers;
    098        Instrument instrument;
    099        Envelope envelope;
    100        structure_header = new byte[ 4 ];
    101        data_input.readFully( structure_header );
    102        instrument_header_length = int_le( structure_header, 0 );
    103        instrument_header = new byte[ instrument_header_length ];
    104        data_input.readFully( instrument_header, 4, instrument_header_length - 4 );
    105        instrument = new Instrument();
    106        instrument.name = ascii_text( instrument_header, 4, 22 );
    107        num_samples = unsigned_short_le( instrument_header, 27 );
    108        if( num_samples > 0 ) {
    109            instrument.set_num_samples( num_samples );
    110            for( idx = 0; idx < 96; idx++ ) {
    111                instrument.set_key_to_sample( idx + 1, instrument_header[ 33 + idx ] & 0xFF );
    112            }
    113            envelope = new Envelope();
    114            env_num_points = instrument_header[ 225 ] & 0xFF;
    115            envelope.set_num_points( env_num_points );
    116            for( idx = 0; idx < env_num_points; idx++ ) {
    117                env_tick = unsigned_short_le( instrument_header, 129 + idx * 4 );
    118                env_ampl = unsigned_short_le( instrument_header, 131 + idx * 4 );
    119                envelope.set_point( idx, env_tick, env_ampl, delta_env );
    120            }
    121            envelope.set_sustain_point( instrument_header[ 227 ] & 0xFF );
    122            envelope.set_loop_points( instrument_header[ 228 ] & 0xFF, instrument_header[ 229 ] & 0xFF );
    123            flags = instrument_header[ 233 ] & 0xFF;
    124            instrument.volume_envelope_active = ( flags & 0x1 ) == 0x1;
    125            envelope.sustain = ( flags & 0x2 ) == 0x2;
    126            envelope.looped = ( flags & 0x4 ) == 0x4;
    127            instrument.set_volume_envelope( envelope );
    128            envelope = new Envelope();
    129            env_num_points = instrument_header[ 226 ] & 0xFF;
    130            envelope.set_num_points( env_num_points );
    131            for( idx = 0; idx < env_num_points; idx++ ) {
    132                env_tick = unsigned_short_le( instrument_header, 177 + idx * 4 );
    133                env_ampl = unsigned_short_le( instrument_header, 179 + idx * 4 );
    134                envelope.set_point( idx, env_tick, env_ampl, delta_env );
    135            }
    136            envelope.set_sustain_point( instrument_header[ 230 ] & 0xFF );
    137            envelope.set_loop_points( instrument_header[ 231 ] & 0xFF, instrument_header[ 232 ] & 0xFF );
    138            flags = instrument_header[ 234 ] & 0xFF;
    139            instrument.panning_envelope_active = ( flags & 0x1 ) == 0x1;
    140            envelope.sustain = ( flags & 0x2 ) == 0x2;
    141            envelope.looped = ( flags & 0x4 ) == 0x4;
    142            instrument.set_panning_envelope( envelope );
    143            instrument.vibrato_type = instrument_header[ 235 ] & 0xFF;
    144            instrument.vibrato_sweep = instrument_header[ 236 ] & 0xFF;
    145            instrument.vibrato_depth = instrument_header[ 237 ] & 0xFF;
    146            instrument.vibrato_rate = instrument_header[ 238 ] & 0xFF;
    147            instrument.volume_fade_out = unsigned_short_le( instrument_header, 239 );
    148            sample_headers = new byte[ num_samples * 40 ];
    149            data_input.readFully( sample_headers );
    150            for( idx = 0; idx < num_samples; idx++ ) {
    151                instrument.set_sample( idx, read_xm_sample( sample_headers, idx, data_input ) );
    152            }
    153        }
    154        return instrument;
    155    }
    156
    157    private static Sample read_xm_sample( byte[] sample_headers, int sample_idx, DataInput data_input ) throws IOException {
    158        int header_offset, sample_length, loop_start, loop_length;
    159        int flags, in_idx, out_idx, sam, last_sam;
    160        int fine_tune, relative_note;
    161        boolean sixteen_bit, ping_pong;
    162        byte[] raw_sample_data;
    163        short[] decoded_sample_data;
    164        Sample sample;
    165        header_offset = sample_idx * 40;
    166        sample = new Sample();
    167        sample_length = int_le( sample_headers, header_offset );
    168        loop_start = int_le( sample_headers, header_offset + 4 );
    169        loop_length = int_le( sample_headers, header_offset + 8 );
    170        sample.volume = sample_headers[ header_offset + 12 ] & 0xFF;
    171        fine_tune = sample_headers[ header_offset + 13 ];
    172        fine_tune = ( fine_tune << IBXM.FP_SHIFT ) / 1536;
    173        sample.set_panning = true;
    174        flags = sample_headers[ header_offset + 14 ] & 0xFF;
    175        if( ( flags & 0x03 ) == 0 ) {
    176            loop_length = 0;
    177        }
    178        ping_pong = ( flags & 0x02 ) == 0x02;
    179        sixteen_bit = ( flags & 0x10 ) == 0x10;
    180        sample.panning = sample_headers[ header_offset + 15 ] & 0xFF;
    181        relative_note = sample_headers[ header_offset + 16 ];
    182        relative_note = ( relative_note << IBXM.FP_SHIFT ) / 12;
    183        sample.transpose = relative_note + fine_tune;
    184        sample.name = ascii_text( sample_headers, header_offset + 18, 22 );
    185        raw_sample_data = new byte[ sample_length ];
    186        try {
    187            data_input.readFully( raw_sample_data );
    188        } catch( EOFException e ) {
    189            System.out.println( "Sample has been truncated!" );
    190        }
    191        in_idx = 0;
    192        out_idx = 0;
    193        sam = 0;
    194        last_sam = 0;
    195        if( sixteen_bit ) {
    196            decoded_sample_data = new short[ sample_length >> 1 ];
    197            while( in_idx < raw_sample_data.length ) {
    198                sam = raw_sample_data[ in_idx ] & 0xFF;
    199                sam = sam | ( ( raw_sample_data[ in_idx + 1 ] & 0xFF ) << 8 );
    200                last_sam = last_sam + sam;
    201                decoded_sample_data[ out_idx ] = ( short ) last_sam;
    202                in_idx += 2;
    203                out_idx += 1;
    204            }
    205            sample.set_sample_data( decoded_sample_data, loop_start >> 1, loop_length >> 1, ping_pong );
    206        } else {
    207            decoded_sample_data = new short[ sample_length ];
    208            while( in_idx < raw_sample_data.length ) {
    209                sam = raw_sample_data[ in_idx ] & 0xFF;
    210                last_sam = last_sam + sam;
    211                decoded_sample_data[ out_idx ] = ( short ) ( last_sam << 8 );
    212                in_idx += 1;
    213                out_idx += 1;
    214            }
    215            sample.set_sample_data( decoded_sample_data, loop_start, loop_length, ping_pong );
    216        }
    217        return sample;
    218    }
    219
    220    private static int unsigned_short_le( byte[] buffer, int offset ) {
    221        int value;
    222        value = buffer[ offset ] & 0xFF;
    223        value = value | ( ( buffer[ offset + 1 ] & 0xFF ) << 8 );
    224        return value;
    225    }
    226
    227    private static int int_le( byte[] buffer, int offset ) {
    228        int value;
    229        value = buffer[ offset ] & 0xFF;
    230        value = value | ( ( buffer[ offset + 1 ] & 0xFF ) << 8 );
    231        value = value | ( ( buffer[ offset + 2 ] & 0xFF ) << 16 );
    232        value = value | ( ( buffer[ offset + 3 ] & 0x7F ) << 24 );
    233        return value;
    234    }
    235
    236    private static String ascii_text( byte[] buffer, int offset, int length ) {
    237        int idx, chr;
    238        byte[] string_buffer;
    239        String string;
    240        string_buffer = new byte[ length ];
    241        for( idx = 0; idx < length; idx++ ) {
    242            chr = buffer[ offset + idx ];
    243            if( chr < 32 ) {
    244                chr = 32;
    245            }
    246            string_buffer[ idx ] = ( byte ) chr;
    247        }
    248        try {
    249            string = new String( string_buffer, 0, length, "ISO-8859-1" );
    250        } catch( UnsupportedEncodingException e ) {
    251            string = "";
    252        }
    253        return string;
    254    }
    255}
    256