package ibxm;
import java.io.*;
public class ProTracker {
public static boolean is_mod( byte[] header_1084_bytes ) {
boolean is_mod;
is_mod = false;
if( calculate_num_channels( header_1084_bytes ) > 0 ) {
is_mod = true;
}
return is_mod;
}
public static Module load_mod( byte[] header_1084_bytes, DataInput data_input ) throws IOException {
int num_channels, channel_idx, panning;
int sequence_length, restart_idx, sequence_idx;
int num_patterns, pattern_idx, instrument_idx;
Module module;
num_channels = calculate_num_channels( header_1084_bytes );
if( num_channels < 1 ) {
throw new IllegalArgumentException( "ProTracker: Unrecognised module format!" );
}
module = new Module();
module.song_title = ascii_text( header_1084_bytes, 0, 20 );
module.pal = ( num_channels == 4 );
module.global_volume = 64;
module.channel_gain = IBXM.FP_ONE * 3 / 8;
module.default_speed = 6;
module.default_tempo = 125;
module.set_num_channels( num_channels );
for( channel_idx = 0; channel_idx < num_channels; channel_idx++ ) {
panning = 64;
if( ( channel_idx & 0x03 ) == 0x01 || ( channel_idx & 0x03 ) == 0x02 ) {
panning = 192;
}
module.set_initial_panning( channel_idx, panning );
}
sequence_length = header_1084_bytes[ 950 ] & 0x7F;
restart_idx = header_1084_bytes[ 951 ] & 0x7F;
if( restart_idx >= sequence_length ) {
restart_idx = 0;
}
module.restart_sequence_index = restart_idx;
module.set_sequence_length( sequence_length );
for( sequence_idx = 0; sequence_idx < sequence_length; sequence_idx++ ) {
module.set_sequence( sequence_idx, header_1084_bytes[ 952 + sequence_idx ] & 0x7F );
}
num_patterns = calculate_num_patterns( header_1084_bytes );
module.set_num_patterns( num_patterns );
for( pattern_idx = 0; pattern_idx < num_patterns; pattern_idx++ ) {
module.set_pattern( pattern_idx, read_mod_pattern( data_input, num_channels ) );
}
module.set_num_instruments( 31 );
for( instrument_idx = 1; instrument_idx <= 31; instrument_idx++ ) {
module.set_instrument( instrument_idx, read_mod_instrument( header_1084_bytes, instrument_idx, data_input ) );
}
return module;
}
private static int calculate_num_patterns( byte[] module_header ) {
int num_patterns, order_entry, pattern_idx;
num_patterns = 0;
for( pattern_idx = 0; pattern_idx < 128; pattern_idx++ ) {
order_entry = module_header[ 952 + pattern_idx ] & 0x7F;
if( order_entry >= num_patterns ) {
num_patterns = order_entry + 1;
}
}
return num_patterns;
}
private static int calculate_num_channels( byte[] module_header ) {
int num_channels;
switch( ( module_header[ 1082 ] << 8 ) | module_header[ 1083 ] ) {
case 0x4b2e: /* M.K. */
case 0x4b21: /* M!K! */
case 0x542e: /* N.T. */
case 0x5434: /* FLT4 */
num_channels = 4;
break;
case 0x484e: /* xCHN */
num_channels = module_header[ 1080 ] - 48;
break;
case 0x4348: /* xxCH */
num_channels = ( ( module_header[ 1080 ] - 48 ) * 10 ) + ( module_header[ 1081 ] - 48 );
break;
default:
/* Not recognised. */
num_channels = 0;
break;
}
return num_channels;
}
private static Pattern read_mod_pattern( DataInput data_input, int num_channels ) throws IOException {
int input_idx, output_idx;
int period, instrument, effect, effect_param;
Pattern pattern;
byte[] input_pattern_data, output_pattern_data;
pattern = new Pattern();
pattern.num_rows = 64;
input_pattern_data = new byte[ 64 * num_channels * 4 ];
output_pattern_data = new byte[ 64 * num_channels * 5 ];
data_input.readFully( input_pattern_data );
input_idx = 0;
output_idx = 0;
while( input_idx < input_pattern_data.length ) {
period = ( input_pattern_data[ input_idx ] & 0x0F ) << 8;
period = period | ( input_pattern_data[ input_idx + 1 ] & 0xFF );
output_pattern_data[ output_idx ] = to_key( period );
instrument = input_pattern_data[ input_idx ] & 0x10;
instrument = instrument | ( ( input_pattern_data[ input_idx + 2 ] & 0xF0 ) >> 4 );
output_pattern_data[ output_idx + 1 ] = ( byte ) instrument;
effect = input_pattern_data[ input_idx + 2 ] & 0x0F;
effect_param = input_pattern_data[ input_idx + 3 ] & 0xFF;
if( effect == 0x01 && effect_param == 0 ) {
/* Portamento up of zero has no effect. */
effect = 0;
}
if( effect == 0x02 && effect_param == 0 ) {
/* Portamento down of zero has no effect. */
effect = 0;
}
if( effect == 0x08 && num_channels == 4 ) {
/* Some Amiga mods use effect 0x08 for reasons other than panning.*/
effect = 0;
effect_param = 0;
}
if( effect == 0x0A && effect_param == 0 ) {
/* Volume slide of zero has no effect.*/
effect = 0;
}
if( effect == 0x05 && effect_param == 0 ) {
/* Porta + Volume slide of zero has no effect.*/
effect = 0x03;
}
if( effect == 0x06 && effect_param == 0 ) {
/* Vibrato + Volume slide of zero has no effect.*/
effect = 0x04;
}
output_pattern_data[ output_idx + 3 ] = ( byte ) effect;
output_pattern_data[ output_idx + 4 ] = ( byte ) effect_param;
input_idx += 4;
output_idx += 5;
}
pattern.set_pattern_data( output_pattern_data );
return pattern;
}
private static Instrument read_mod_instrument( byte[] mod_header, int idx, DataInput data_input ) throws IOException {
int header_offset, sample_data_length;
int loop_start, loop_length, sample_idx, fine_tune;
Instrument instrument;
Sample sample;
byte[] raw_sample_data;
short[] sample_data;
header_offset = ( idx - 1 ) * 30 + 20;
instrument = new Instrument();
instrument.name = ascii_text( mod_header, header_offset, 22 );
sample = new Sample();
sample_data_length = unsigned_short_be( mod_header, header_offset + 22 ) << 1;
fine_tune = mod_header[ header_offset + 24 ] & 0x0F;
if( fine_tune > 7 ) {
fine_tune -= 16;
}
sample.transpose = ( fine_tune << IBXM.FP_SHIFT ) / 96;
sample.volume = mod_header[ header_offset + 25 ] & 0x7F;
loop_start = unsigned_short_be( mod_header, header_offset + 26 ) << 1;
loop_length = unsigned_short_be( mod_header, header_offset + 28 ) << 1;
if( loop_length < 4 ) {
loop_length = 0;
}
raw_sample_data = new byte[ sample_data_length ];
sample_data = new short[ sample_data_length ];
try {
data_input.readFully( raw_sample_data );
} catch( EOFException e ) {
System.out.println( "ProTracker: Instrument " + idx + " has samples missing." );
}
for( sample_idx = 0; sample_idx < raw_sample_data.length; sample_idx++ ) {
sample_data[ sample_idx ] = ( short ) ( raw_sample_data[ sample_idx ] << 8 );
}
sample.set_sample_data( sample_data, loop_start, loop_length, false );
instrument.set_num_samples( 1 );
instrument.set_sample( 0, sample );
return instrument;
}
private static byte to_key( int period ) {
int oct, key;
if( period < 32 ) {
key = 0;
} else {
oct = LogTable.log_2( 7256 ) - LogTable.log_2( period );
if( oct < 0 ) {
key = 0;
} else {
key = oct * 12;
key = key >> ( IBXM.FP_SHIFT - 1 );
key = ( key >> 1 ) + ( key & 1 );
}
}
return ( byte ) key;
}
private static int unsigned_short_be( byte[] buf, int offset ) {
int value;
value = ( buf[ offset ] & 0xFF ) << 8;
value = value | ( buf[ offset + 1 ] & 0xFF );
return value;
}
private static String ascii_text( byte[] buffer, int offset, int length ) {
int idx, chr;
byte[] string_buffer;
String string;
string_buffer = new byte[ length ];
for( idx = 0; idx < length; idx++ ) {
chr = buffer[ offset + idx ];
if( chr < 32 ) {
chr = 32;
}
string_buffer[ idx ] = ( byte ) chr;
}
try {
string = new String( string_buffer, 0, length, "ISO-8859-1" );
} catch( UnsupportedEncodingException e ) {
string = "";
}
return string;
}
}