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use crate::import::patternslot::PatternSlot;
use crate::prelude::*;
use alloc::{vec, vec::Vec};
#[derive(Debug)]
pub struct PatternHelper {
pub version: usize,
pub songs: Vec<Vec<usize>>,
pub channels: Vec<Vec<u8>>,
pub tracks: Vec<Vec<u8>>,
}
impl PatternHelper {
pub fn new(
version: usize,
songs: Vec<Vec<usize>>,
channels: Vec<Vec<u8>>,
tracks: Vec<Vec<u8>>,
) -> Self {
Self {
version,
songs,
channels,
tracks,
}
}
fn get_track(&self, _track_index: usize, source: &[u8]) -> Vec<PatternSlot> {
let mut track: Vec<PatternSlot> = vec![];
let mut index: usize = 0;
let mut last_instr: Option<usize> = None;
while source[index] != 255 {
let mut current = PatternSlot::default();
let length = source[index] & 0b0001_1111; // 0-31
let release = (source[index] & 0b0010_0000) == 0;
let append = (source[index] & 0b0100_0000) == 0;
let instr_or_portamento = (source[index] & 0b1000_0000) != 0;
if append {
index += 1;
if instr_or_portamento {
match self.version {
10 => {
if source[index] & 0b1000_0000 == 0 {
current.instrument = Some((source[index] & 0b0111_1111) as usize);
last_instr = current.instrument;
} else {
// Portamento: bit 7 = portamento flag, bits 1-6 = speed,
// bit 0 = direction (0=up, 1=down).
// Speed is raw 16-bit freq delta per frame, >> 1 to scale for XM effects.
let p = source[index] & 0b0111_1110;
if p != 0 {
current.effect_parameter = p >> 1;
if source[index] & 1 == 0 {
current.effect_type = 1; // portamento up
} else {
current.effect_type = 2; // portamento down
}
}
}
}
15 => {
// Spellbound variant: byte 2 is always instrument, never portamento
if source[index] & 0b1000_0000 == 0 {
current.instrument = Some((source[index] & 0b0111_1111) as usize);
last_instr = current.instrument;
}
}
_ => {
// Version 20+: portamento uses 14-bit value across 2 bytes
// Byte 1: bit 7=portamento, bit 6=direction, bits 5-0=high 6 bits
// Byte 2: low 8 bits of portamento speed
if source[index] & 0b1000_0000 == 0 {
current.instrument = Some((source[index] & 0b0111_1111) as usize);
last_instr = current.instrument;
} else {
if index + 2 >= source.len() {
#[cfg(feature = "std")]
println!(
"Track {}, International Karate overflow?",
_track_index
);
index -= 2;
} else {
let direction_down = source[index] & 0b0100_0000 != 0;
let p: u16 = ((source[index] as u16 & 0b0011_1111) << 8)
| source[index + 1] as u16;
index += 1;
if p != 0 {
// Scale 14-bit value (0-16383) to 8-bit (0-255)
current.effect_parameter = (p >> 6).min(255) as u8;
if direction_down {
current.effect_type = 2; // portamento down
} else {
current.effect_type = 1; // portamento up
}
}
}
}
}
}
index += 1;
}
// Note byte: bits 0-6 = note number (0-84 for 7 octaves)
// Values > 96 are overflows in the original SID data where the
// player reads from memory locations instead of the frequency table.
// The hardcoded fixups below reproduce the original (buggy) behaviour.
let n = source[index] & 0b0111_1111;
let note = if n > 8 * 12 {
match n {
96 => 0,
97 => 0,
98 => 12,
100 => 3,
104 => 65,
105 => 65,
107 => 6,
127 => 0,
_ => n & 0b0011_1111, // clamp to 0-63 for unmapped overflows
}
} else {
n
};
current.note = note.try_into().unwrap_or(Pitch::None);
}
// Bit 7 of the note byte is unused in versions 10/15/20.
// Version 30 (Delta) may use it as a reset-effect flag,
// but no disassembly confirms this — left unimplemented.
if release {
if current.note == Pitch::None {
current.note = Pitch::Off;
} else {
current.volume = 0x50; // set volume 64 (XM encoding)
}
current.instrument = last_instr;
}
index += 1;
track.push(current);
if length != 0 {
let current = PatternSlot::default();
for _ in 0..length {
track.push(current);
}
}
}
track
}
fn get_tracks(&self) -> Vec<Vec<PatternSlot>> {
let mut tracks: Vec<Vec<PatternSlot>> = vec![];
for (i, t) in self.tracks.iter().enumerate() {
tracks.push(self.get_track(i, t));
}
tracks
}
fn get_pattern_order(&self, song_number: usize) -> Vec<&Vec<u8>> {
let mut pattern_order: Vec<&Vec<u8>> = vec![];
for s_index in &self.songs[song_number] {
pattern_order.push(&self.channels[*s_index]);
}
pattern_order
}
pub fn get_patterns(&self, song_number: usize) -> Vec<Vec<Vec<PatternSlot>>> {
let tracks = self.get_tracks();
let pattern_order = self.get_pattern_order(song_number);
let po_len = pattern_order.len();
let mut all_ok: Vec<bool> = vec![false; po_len];
let mut i_n: [usize; 3] = [0; 3];
let mut patterns: Vec<Vec<Vec<PatternSlot>>> = vec![];
loop {
let mut trks: Vec<&Vec<PatternSlot>> = vec![];
for k in 0..po_len {
if pattern_order[k][i_n[k]] as usize >= tracks.len() {
#[cfg(feature = "std")]
println!("No way!? {}", pattern_order[k][i_n[k]]);
// special case for commando!?
let what_to_do: usize = match pattern_order[k][i_n[k]] {
111 => 3,
112 => 2,
_ => 0,
};
trks.push(&tracks[what_to_do]);
} else {
trks.push(&tracks[pattern_order[k][i_n[k]] as usize]);
}
}
let mut trks_total_len = trks.iter().map(|sublist| sublist.len()).max().unwrap_or(0);
let mut pattern: Vec<Vec<PatternSlot>> = vec![];
let mut j: [usize; 3] = [0; 3];
while trks_total_len != 0 {
let mut line: Vec<PatternSlot> = vec![];
for k in 0..po_len {
if j[k] >= trks[k].len() {
i_n[k] += 1;
if i_n[k] >= pattern_order[k].len() {
i_n[k] = 0;
}
j[k] = 0;
if pattern_order[k][i_n[k]] as usize >= tracks.len() {
#[cfg(feature = "std")]
println!("No way!? {}", pattern_order[k][i_n[k]]);
// special case for commando!?
let what_to_do: usize = match pattern_order[k][i_n[k]] {
111 => 3,
112 => 2,
_ => 0,
};
trks[k] = &tracks[what_to_do];
} else {
trks[k] = &tracks[pattern_order[k][i_n[k]] as usize];
}
if trks[k].len() > trks_total_len {
trks_total_len = trks[k].len();
}
}
line.push(trks[k][j[k]]);
j[k] += 1;
}
trks_total_len -= 1;
pattern.push(line);
}
patterns.push(pattern);
for k in 0..po_len {
i_n[k] += 1;
if i_n[k] >= pattern_order[k].len() {
i_n[k] = 0;
// A hack to exit
all_ok[k] = true;
if all_ok.iter().all(|&b| b) {
return patterns;
}
} else {
// Original way to exit
if pattern_order[k][i_n[k]] == 254 {
return patterns;
}
}
}
}
}
pub fn cleanup_patterns(
source: &[Vec<Vec<PatternSlot>>],
) -> (Vec<Vec<Vec<PatternSlot>>>, Vec<usize>) {
let mut dest: Vec<Vec<Vec<PatternSlot>>> = Vec::new();
let mut order: Vec<usize> = Vec::new();
let mut seen_map: Vec<(Vec<Vec<PatternSlot>>, usize)> = Vec::new(); // Vec of (Pattern, index in dest)
for pattern in source.iter() {
if let Some(&(_, idx)) = seen_map.iter().find(|(p, _)| p == pattern) {
order.push(idx);
} else {
let new_idx = dest.len();
dest.push(pattern.clone());
seen_map.push((pattern.clone(), new_idx));
order.push(new_idx);
}
}
(dest, order)
}
pub fn split_large_patterns(patterns: &mut Vec<Vec<Vec<PatternSlot>>>) {
let max_size = 256;
let mut i = 0;
while i < patterns.len() {
let current_pattern = &patterns[i];
if current_pattern.len() > max_size {
let num_splits = current_pattern.len().div_ceil(max_size);
let mut new_patterns = Vec::new();
for j in 0..num_splits {
let start = j * max_size;
let end = current_pattern.len().min(start + max_size);
let new_pattern = current_pattern[start..end].to_vec();
new_patterns.push(new_pattern);
}
patterns.splice(i..=i, new_patterns);
} else {
i += 1;
}
}
}
}