@import url("/assets/md.css")feat: Marquee, Lower dither opacity at top, DVD Logo should be separate function, Release Builds should work, advance_width should be f64 to save bytes, Vendor Micromod-RS, Add Timing Steps

@import url("/assets/md.css")

4 files changed, 909 insertions, 0 deletions

diff --git a/src/vendored/micromod-rs/ATTRIBUTION b/src/vendored/micromod-rs/ATTRIBUTION
new file mode 100644
index 0000000..2f5cc0f
--- /dev/null
+++ b/src/vendored/micromod-rs/ATTRIBUTION
@@ -0,0 +1 @@
+https://github.com/aspizu/micromod-rust/tree/bcf4f62610c2a7b4b417cbde79241efdaa7ed71d
\ No newline at end of file
diff --git a/src/vendored/micromod-rs/COPYING b/src/vendored/micromod-rs/COPYING
new file mode 100644
index 0000000..f5dc43e
--- /dev/null
+++ b/src/vendored/micromod-rs/COPYING
@@ -0,0 +1,37 @@
+---
+Copyright (c) 2019, Martin Cameron
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or
+without modification, are permitted provided that the
+following conditions are met:
+
+ * Redistributions of source code must retain the above
+   copyright notice, this list of conditions and the
+   following disclaimer.
+
+ * Redistributions in binary form must reproduce the
+   above copyright notice, this list of conditions and the
+   following disclaimer in the documentation and/or other
+   materials provided with the distribution.
+ 
+ * Neither the name of the organization nor the names of
+   its contributors may be used to endorse or promote
+   products derived from this software without specific
+   prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
+MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
+CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
+INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
+GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
+BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
+OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+POSSIBILITY OF SUCH DAMAGE.
+---
\ No newline at end of file
diff --git a/src/vendored/micromod-rs/consts.rs b/src/vendored/micromod-rs/consts.rs
new file mode 100644
index 0000000..092766d
--- /dev/null
+++ b/src/vendored/micromod-rs/consts.rs
@@ -0,0 +1,11 @@
+pub static MICROMOD_VERSION: &str = "Micromod Protracker replay 20180625 (c)mumart@gmail.com";
+pub static FINE_TUNING: [u16; 16] = [
+  4340, 4308, 4277, 4247, 4216, 4186, 4156, 4126, 4096, 4067, 4037, 4008, 3979, 3951, 3922, 3894,
+];
+pub static ARP_TUNING: [u16; 16] = [
+  4096, 3866, 3649, 3444, 3251, 3069, 2896, 2734, 2580, 2435, 2299, 2170, 2048, 1933, 1825, 1722,
+];
+pub static SINE_TABLE: [u8; 32] = [
+  0, 24, 49, 74, 97, 120, 141, 161, 180, 197, 212, 224, 235, 244, 250, 253, 255, 253, 250, 244,
+  235, 224, 212, 197, 180, 161, 141, 120, 97, 74, 49, 24,
+];
diff --git a/src/vendored/micromod-rs/mod.rs b/src/vendored/micromod-rs/mod.rs
new file mode 100644
index 0000000..1d1934a
--- /dev/null
+++ b/src/vendored/micromod-rs/mod.rs
@@ -0,0 +1,860 @@
+//! Experiment with converting [Micromod](https://github.com/martincameron/micromod) with
+//! [c2rust](https://c2rust.com/).
+//!
+//! Safetyfication done manually
+
+#![warn(missing_docs)]
+
+mod consts;
+
+use std::cmp::Ordering;
+
+#[derive(Copy, Clone, Default)]
+struct Channel {
+  note: Note,
+  period: u16,
+  porta_period: u16,
+  sample_offset: usize,
+  sample_idx: usize,
+  step: usize,
+  volume: u8,
+  panning: u8,
+  fine_tune: u8,
+  ampl: u8,
+  mute: u8,
+  id: u8,
+  instrument: u8,
+  assigned: u8,
+  porta_speed: u8,
+  pl_row: u8,
+  fx_count: u8,
+  vibrato_type: u8,
+  vibrato_phase: u8,
+  vibrato_speed: u8,
+  vibrato_depth: u8,
+  tremolo_type: u8,
+  tremolo_phase: u8,
+  tremolo_speed: u8,
+  tremolo_depth: u8,
+  tremolo_add: i8,
+  vibrato_add: i8,
+  arpeggio_add: i8,
+}
+#[derive(Copy, Clone, Default)]
+struct Note {
+  key: u16,
+  instrument: u8,
+  effect: u8,
+  param: u8,
+}
+#[derive(Copy, Clone)]
+struct Instrument<'src> {
+  volume: u8,
+  fine_tune: u8,
+  loop_start: usize,
+  loop_length: usize,
+  sample_data: &'src [i8],
+}
+
+impl Instrument<'_> {
+  fn dummy() -> Self {
+    Self {
+      volume: 0,
+      fine_tune: 0,
+      loop_start: 0,
+      loop_length: 0,
+      sample_data: &[],
+    }
+  }
+}
+
+/// Immutable source data of the module
+struct ModSrc<'src> {
+  instruments: Vec<Instrument<'src>>,
+  module_data: &'src [i8],
+  pattern_data: &'src [u8],
+  sequence: &'src [u8],
+  num_patterns: isize,
+  num_channels: isize,
+  song_length: isize,
+}
+
+#[derive(Default)]
+struct PlaybackState {
+  gain: isize,
+  c2_rate: isize,
+  tick_len: isize,
+  tick_offset: isize,
+  pattern: isize,
+  break_pattern: isize,
+  row: isize,
+  next_row: isize,
+  tick: isize,
+  speed: isize,
+  pl_count: isize,
+  pl_channel: isize,
+  random_seed: isize,
+}
+
+/// A micromod decoding instance thingy.
+pub struct MmC2r<'src> {
+  sample_rate: isize,
+  channels: [Channel; 16],
+  src: ModSrc<'src>,
+  playback: PlaybackState,
+}
+
+fn calculate_num_patterns(module_header: &[i8]) -> isize {
+  let mut num_patterns_0;
+  let mut order_entry;
+  let mut pattern_0;
+  num_patterns_0 = 0;
+  pattern_0 = 0;
+  while pattern_0 < 128 {
+    order_entry = (module_header[(952 + pattern_0) as usize] as i32 & 0x7f_i32) as isize;
+    if order_entry >= num_patterns_0 {
+      num_patterns_0 = order_entry + 1;
+    }
+    pattern_0 += 1;
+  }
+  num_patterns_0
+}
+
+fn calculate_num_channels(module_header: &[i8]) -> Option<isize> {
+  const MAX_CHANNELS: isize = 16;
+  let numchan: isize = match ((module_header[1082] as isize) << 8) | module_header[1083] as isize {
+    // M.K.  M!K!     N.T.     FLT4
+    0x4b2e | 0x4b21 | 0x542e | 0x5434 => 4,
+    // xCHN
+    0x484e => (module_header[1080] - 48) as isize,
+    // xxCH
+    0x4348 => (((module_header[1080] - 48) * 10) + (module_header[1081] - 48)) as isize,
+    // Not recognised.
+    _ => 0,
+  };
+  if numchan > MAX_CHANNELS {
+    None
+  } else {
+    Some(numchan)
+  }
+}
+fn unsigned_short_big_endian(buf: &[i8], offset: isize) -> isize {
+  ((buf[offset as usize] as i32 & 0xff_i32) << 8 | buf[(offset + 1) as usize] as i32 & 0xff_i32)
+    as isize
+}
+fn set_tempo(tempo: isize, tick_len: &mut isize, sample_rate: isize) {
+  *tick_len = ((sample_rate << 1) + (sample_rate >> 1)) / tempo;
+}
+fn update_frequency(chan: &mut Channel, sample_rate: isize, gain: &mut isize, c2_rate: &mut isize) {
+  let mut period;
+  let mut volume;
+
+  period = (chan.period as i32 + chan.vibrato_add as i32) as isize;
+  period = (period * consts::ARP_TUNING[chan.arpeggio_add as usize] as isize) >> 11;
+  period = (period >> 1) + (period & 1);
+  if period < 14 {
+    period = 6848;
+  }
+  let freq = (*c2_rate * 428 / period) as usize;
+  chan.step = (freq << 14).wrapping_div(sample_rate as usize);
+  volume = (chan.volume as i32 + chan.tremolo_add as i32) as isize;
+  volume = volume.clamp(0, 64);
+  chan.ampl = ((volume * *gain) >> 5) as u8;
+}
+fn tone_portamento(chan: &mut Channel) {
+  let mut source;
+
+  source = chan.period as isize;
+  let dest = chan.porta_period as isize;
+  match source.cmp(&dest) {
+    Ordering::Less => {
+      source += chan.porta_speed as isize;
+      if source > dest {
+        source = dest;
+      }
+    }
+    Ordering::Equal => { /* Do absolutely nothing */ }
+    Ordering::Greater => {
+      source -= chan.porta_speed as isize;
+      if source < dest {
+        source = dest;
+      }
+    }
+  }
+  chan.period = source as u16;
+}
+fn volume_slide(chan: &mut Channel, param: isize) {
+  let mut volume;
+  volume = chan.volume as isize + (param >> 4) - (param & 0xf);
+  volume = volume.clamp(0, 64);
+  chan.volume = volume as u8;
+}
+fn waveform(phase: isize, type_0: isize, random_seed: &mut isize) -> isize {
+  let mut amplitude: isize = 0;
+  match type_0 & 0x3 {
+    0 => {
+      amplitude = consts::SINE_TABLE[(phase & 0x1f) as usize] as isize;
+      if phase & 0x20 > 0 {
+        amplitude = -amplitude;
+      }
+    }
+    1 => {
+      amplitude = 255 - (((phase + 0x20) & 0x3f) << 3);
+    }
+    2 => {
+      amplitude = 255 - ((phase & 0x20) << 4);
+    }
+    3 => {
+      amplitude = (*random_seed >> 20) - 255;
+      *random_seed = (*random_seed * 65 + 17) & 0x1fffffff;
+    }
+    _ => {}
+  }
+  amplitude
+}
+fn vibrato(chan: &mut Channel, random_seed: &mut isize) {
+  chan.vibrato_add = ((waveform(
+    chan.vibrato_phase as isize,
+    chan.vibrato_type as isize,
+    random_seed,
+  ) * chan.vibrato_depth as isize)
+    >> 7) as i8;
+}
+fn tremolo(chan: &mut Channel, random_seed: &mut isize) {
+  chan.tremolo_add = ((waveform(
+    chan.tremolo_phase as isize,
+    chan.tremolo_type as isize,
+    random_seed,
+  ) * chan.tremolo_depth as isize)
+    >> 6) as i8;
+}
+fn trigger(channel: &mut Channel, instruments: &[Instrument]) {
+  let period;
+
+  let ins = channel.note.instrument as isize;
+  if ins > 0 && ins < 32 {
+    channel.assigned = ins as u8;
+    channel.sample_offset = 0;
+    channel.fine_tune = instruments[ins as usize].fine_tune;
+    channel.volume = instruments[ins as usize].volume;
+    if instruments[ins as usize].loop_length > 0 && channel.instrument as i32 > 0 {
+      channel.instrument = ins as u8;
+    }
+  }
+  if channel.note.effect as i32 == 0x9_i32 {
+    channel.sample_offset = ((channel.note.param as i32 & 0xff_i32) << 8) as usize;
+  } else if channel.note.effect as i32 == 0x15_i32 {
+    channel.fine_tune = channel.note.param;
+  }
+  if channel.note.key as i32 > 0 {
+    period = ((channel.note.key as i32
+      * consts::FINE_TUNING[(channel.fine_tune as i32 & 0xf_i32) as usize] as i32)
+      >> 11) as isize;
+    channel.porta_period = ((period >> 1) + (period & 1)) as u16;
+    if channel.note.effect as i32 != 0x3_i32 && channel.note.effect as i32 != 0x5_i32 {
+      channel.instrument = channel.assigned;
+      channel.period = channel.porta_period;
+      channel.sample_idx = channel.sample_offset << 14;
+      if (channel.vibrato_type as i32) < 4 {
+        channel.vibrato_phase = 0;
+      }
+      if (channel.tremolo_type as i32) < 4 {
+        channel.tremolo_phase = 0;
+      }
+    }
+  }
+}
+fn channel_row(chan: &mut Channel, sample_rate: isize, src: &ModSrc, playback: &mut PlaybackState) {
+  let volume;
+  let period;
+  let effect = chan.note.effect as isize;
+  let param = chan.note.param as isize;
+  let fresh0 = &mut chan.fx_count;
+  *fresh0 = 0;
+  let fresh1 = &mut chan.arpeggio_add;
+  *fresh1 = *fresh0 as i8;
+  let fresh2 = &mut chan.tremolo_add;
+  *fresh2 = *fresh1;
+  chan.vibrato_add = *fresh2;
+  if !(effect == 0x1d && param > 0) {
+    trigger(chan, &src.instruments);
+  }
+  match effect {
+    3 => {
+      if param > 0 {
+        chan.porta_speed = param as u8;
+      }
+    }
+    4 => {
+      if param & 0xf0 > 0 {
+        chan.vibrato_speed = (param >> 4) as u8;
+      }
+      if param & 0xf > 0 {
+        chan.vibrato_depth = (param & 0xf) as u8;
+      }
+      vibrato(chan, &mut playback.random_seed);
+    }
+    6 => {
+      vibrato(chan, &mut playback.random_seed);
+    }
+    7 => {
+      if param & 0xf0 > 0 {
+        chan.tremolo_speed = (param >> 4) as u8;
+      }
+      if param & 0xf > 0 {
+        chan.tremolo_depth = (param & 0xf) as u8;
+      }
+      tremolo(chan, &mut playback.random_seed);
+    }
+    8 => {
+      if src.num_channels != 4 {
+        chan.panning = (if param < 128 { param } else { 127 }) as u8;
+      }
+    }
+    11 => {
+      if playback.pl_count < 0 {
+        playback.break_pattern = param;
+        playback.next_row = 0;
+      }
+    }
+    12 => {
+      chan.volume = (if param > 64 { 64 } else { param }) as u8;
+    }
+    13 => {
+      if playback.pl_count < 0 {
+        if playback.break_pattern < 0 {
+          playback.break_pattern = playback.pattern + 1;
+        }
+        playback.next_row = (param >> 4) * 10 + (param & 0xf);
+        if playback.next_row >= 64 {
+          playback.next_row = 0;
+        }
+      }
+    }
+    15 => {
+      if param > 0 {
+        if param < 32 {
+          playback.speed = param;
+          playback.tick = playback.speed;
+        } else {
+          set_tempo(param, &mut playback.tick_len, sample_rate);
+        }
+      }
+    }
+    17 => {
+      period = chan.period as isize - param;
+      chan.period = (if period < 0 { 0 } else { period }) as u16;
+    }
+    18 => {
+      period = chan.period as isize + param;
+      chan.period = (if period > 65535 { 65535 } else { period }) as u16;
+    }
+    20 => {
+      if param < 8 {
+        chan.vibrato_type = param as u8;
+      }
+    }
+    22 => {
+      if param == 0 {
+        chan.pl_row = playback.row as u8;
+      }
+      if (chan.pl_row as isize) < playback.row && playback.break_pattern < 0 {
+        if playback.pl_count < 0 {
+          playback.pl_count = param;
+          playback.pl_channel = chan.id as isize;
+        }
+        if playback.pl_channel == chan.id as isize {
+          if playback.pl_count == 0 {
+            chan.pl_row = (playback.row + 1) as u8;
+          } else {
+            playback.next_row = chan.pl_row as isize;
+          }
+          playback.pl_count -= 1;
+        }
+      }
+    }
+    23 => {
+      if param < 8 {
+        chan.tremolo_type = param as u8;
+      }
+    }
+    26 => {
+      volume = chan.volume as isize + param;
+      chan.volume = (if volume > 64 { 64 } else { volume }) as u8;
+    }
+    27 => {
+      volume = chan.volume as isize - param;
+      chan.volume = (if volume < 0 { 0 } else { volume }) as u8;
+    }
+    28 => {
+      if param <= 0 {
+        chan.volume = 0;
+      }
+    }
+    30 => {
+      playback.tick = playback.speed + playback.speed * param;
+    }
+    _ => {}
+  }
+  update_frequency(chan, sample_rate, &mut playback.gain, &mut playback.c2_rate);
+}
+fn channel_tick(
+  chan: &mut Channel,
+  sample_rate: isize,
+  gain: &mut isize,
+  c2_rate: &mut isize,
+  random_seed: &mut isize,
+  instruments: &[Instrument],
+) {
+  let period;
+  let effect = chan.note.effect as isize;
+  let param = chan.note.param as isize;
+  let fresh3 = &mut chan.fx_count;
+  *fresh3 = (*fresh3).wrapping_add(1);
+  match effect {
+    1 => {
+      period = chan.period as isize - param;
+      chan.period = (if period < 0 { 0 } else { period }) as u16;
+    }
+    2 => {
+      period = chan.period as isize + param;
+      chan.period = (if period > 65535 { 65535 } else { period }) as u16;
+    }
+    3 => {
+      tone_portamento(chan);
+    }
+    4 => {
+      let fresh4 = &mut chan.vibrato_phase;
+      *fresh4 = (*fresh4 as i32 + chan.vibrato_speed as i32) as u8;
+      vibrato(chan, random_seed);
+    }
+    5 => {
+      tone_portamento(chan);
+      volume_slide(chan, param);
+    }
+    6 => {
+      let fresh5 = &mut chan.vibrato_phase;
+      *fresh5 = (*fresh5 as i32 + chan.vibrato_speed as i32) as u8;
+      vibrato(chan, random_seed);
+      volume_slide(chan, param);
+    }
+    7 => {
+      let fresh6 = &mut chan.tremolo_phase;
+      *fresh6 = (*fresh6 as i32 + chan.tremolo_speed as i32) as u8;
+      tremolo(chan, random_seed);
+    }
+    10 => {
+      volume_slide(chan, param);
+    }
+    14 => {
+      if chan.fx_count as i32 > 2 {
+        chan.fx_count = 0;
+      }
+      if chan.fx_count as i32 == 0 {
+        chan.arpeggio_add = 0;
+      }
+      if chan.fx_count as i32 == 1 {
+        chan.arpeggio_add = (param >> 4) as i8;
+      }
+      if chan.fx_count as i32 == 2 {
+        chan.arpeggio_add = (param & 0xf) as i8;
+      }
+    }
+    25 => {
+      if chan.fx_count as isize >= param {
+        chan.fx_count = 0;
+        chan.sample_idx = 0;
+      }
+    }
+    28 => {
+      if param == chan.fx_count as isize {
+        chan.volume = 0;
+      }
+    }
+    29 => {
+      if param == chan.fx_count as isize {
+        trigger(chan, instruments);
+      }
+    }
+    _ => {}
+  }
+  if effect > 0 {
+    update_frequency(chan, sample_rate, gain, c2_rate);
+  }
+}
+fn sequence_row(state: &mut MmC2r) -> bool {
+  let mut song_end = false;
+  let mut chan_idx;
+  let mut pat_offset;
+  let mut effect;
+  let mut param;
+  let mut note;
+  if state.playback.next_row < 0 {
+    state.playback.break_pattern = state.playback.pattern + 1;
+    state.playback.next_row = 0;
+  }
+  if state.playback.break_pattern >= 0 {
+    if state.playback.break_pattern >= state.src.song_length {
+      state.playback.next_row = 0;
+      state.playback.break_pattern = state.playback.next_row;
+    }
+    if state.playback.break_pattern <= state.playback.pattern {
+      song_end = true;
+    }
+    state.playback.pattern = state.playback.break_pattern;
+    chan_idx = 0;
+    while chan_idx < state.src.num_channels {
+      state.channels[chan_idx as usize].pl_row = 0;
+      chan_idx += 1;
+    }
+    state.playback.break_pattern = -1;
+  }
+  state.playback.row = state.playback.next_row;
+  state.playback.next_row = state.playback.row + 1;
+  if state.playback.next_row >= 64 {
+    state.playback.next_row = -1;
+  }
+  pat_offset = ((state.src.sequence[state.playback.pattern as usize] as i32 * 64) as isize
+    + state.playback.row)
+    * state.src.num_channels
+    * 4;
+  chan_idx = 0;
+  while chan_idx < state.src.num_channels {
+    note = &mut (state.channels[chan_idx as usize]).note;
+    let pattern_data = state.src.pattern_data;
+    note.key = ((pattern_data[pat_offset as usize] as i32 & 0xf_i32) << 8) as u16;
+    let fresh7 = &mut note.key;
+    *fresh7 = (*fresh7 as i32 | pattern_data[(pat_offset + 1) as usize] as i32) as u16;
+    note.instrument = (pattern_data[(pat_offset + 2) as usize] as i32 >> 4) as u8;
+    let fresh8 = &mut note.instrument;
+    *fresh8 = (*fresh8 as i32 | pattern_data[pat_offset as usize] as i32 & 0x10_i32) as u8;
+    effect = (pattern_data[(pat_offset + 2) as usize] as i32 & 0xf_i32) as isize;
+    param = pattern_data[(pat_offset + 3) as usize] as isize;
+    pat_offset += 4;
+    if effect == 0xe {
+      effect = 0x10 | param >> 4;
+      param &= 0xf;
+    }
+    if effect == 0 && param > 0 {
+      effect = 0xe;
+    }
+    note.effect = effect as u8;
+    note.param = param as u8;
+    channel_row(
+      &mut state.channels[chan_idx as usize],
+      state.sample_rate,
+      &state.src,
+      &mut state.playback,
+    );
+    chan_idx += 1;
+  }
+  song_end
+}
+fn sequence_tick(state: &mut MmC2r) -> bool {
+  let mut song_end = false;
+  let mut chan_idx;
+  state.playback.tick -= 1;
+  if state.playback.tick <= 0 {
+    state.playback.tick = state.playback.speed;
+    song_end = sequence_row(state);
+  } else {
+    chan_idx = 0;
+    while chan_idx < state.src.num_channels {
+      channel_tick(
+        &mut state.channels[chan_idx as usize],
+        state.sample_rate,
+        &mut state.playback.gain,
+        &mut state.playback.c2_rate,
+        &mut state.playback.random_seed,
+        &state.src.instruments,
+      );
+      chan_idx += 1;
+    }
+  }
+  song_end
+}
+fn resample(
+  chan: &mut Channel,
+  buf: &mut [i16],
+  offset: isize,
+  count: isize,
+  instruments: &[Instrument],
+) {
+  let mut epos;
+  let mut buf_idx: usize = (offset << 1) as usize;
+  let buf_end: usize = ((offset + count) << 1) as usize;
+  let mut sidx: usize = chan.sample_idx;
+  let step: usize = chan.step;
+  let llen: usize = instruments[chan.instrument as usize].loop_length;
+  let lep1: usize = (instruments[chan.instrument as usize].loop_start).wrapping_add(llen);
+  let sdat = instruments[chan.instrument as usize].sample_data;
+  let mut ampl: i16 = (if chan.mute == 0 { chan.ampl as i32 } else { 0 }) as i16;
+  let lamp: i16 = ((ampl as i32 * (127_i32 - chan.panning as i32)) >> 5) as i16;
+  let ramp: i16 = ((ampl as i32 * chan.panning as i32) >> 5) as i16;
+  while buf_idx < buf_end {
+    if sidx >= lep1 {
+      if llen <= 16384 {
+        sidx = lep1;
+        break;
+      } else {
+        while sidx >= lep1 {
+          sidx = sidx.wrapping_sub(llen);
+        }
+      }
+    }
+    epos = sidx.wrapping_add((buf_end.wrapping_sub(buf_idx) >> 1).wrapping_mul(step));
+    if lamp as i32 != 0 || ramp as i32 != 0 {
+      if epos > lep1 {
+        epos = lep1;
+      }
+      if lamp as i32 != 0 && ramp as i32 != 0 {
+        while sidx < epos {
+          ampl = sdat[(sidx >> 14) as usize] as i16;
+          let fresh9 = buf_idx;
+          buf_idx = buf_idx.wrapping_add(1);
+          let fresh10 = &mut (buf[fresh9 as usize]);
+          *fresh10 = (*fresh10 as i32 + ((ampl as i32 * lamp as i32) >> 2)) as i16;
+          let fresh11 = buf_idx;
+          buf_idx = buf_idx.wrapping_add(1);
+          let fresh12 = &mut (buf[fresh11 as usize]);
+          *fresh12 = (*fresh12 as i32 + ((ampl as i32 * ramp as i32) >> 2)) as i16;
+          sidx = sidx.wrapping_add(step);
+        }
+      } else {
+        if ramp != 0 {
+          buf_idx = buf_idx.wrapping_add(1);
+        }
+        while sidx < epos {
+          let fresh13 = &mut (buf[buf_idx as usize]);
+          *fresh13 = (*fresh13 as i32 + sdat[(sidx >> 14) as usize] as i32 * ampl as i32) as i16;
+          buf_idx = buf_idx.wrapping_add(2);
+          sidx = sidx.wrapping_add(step);
+        }
+        buf_idx &= -2_i32 as usize;
+      }
+    } else {
+      buf_idx = buf_end;
+      sidx = epos;
+    }
+  }
+  chan.sample_idx = sidx;
+}
+
+/// Get a nice version string. I guess.
+pub fn version() -> &'static str {
+  consts::MICROMOD_VERSION
+}
+
+/// An error that can happen when trying to initialize micromod
+#[derive(Debug)]
+pub enum InitError {
+  /// Number of channels is incorrect
+  ChannelNumIncorrect,
+  /// Sampling rate is incorrect (below 8khz?)
+  SamplingRateIncorrect,
+}
+
+impl MmC2r<'_> {
+  /// Create a new micromod decoder apparatus.
+  pub fn new(data: &[u8], sample_rate: isize) -> Result<MmC2r, InitError> {
+    let num_channels = match calculate_num_channels(bytemuck::cast_slice(data)) {
+      Some(num_channels) => num_channels,
+      None => return Err(InitError::ChannelNumIncorrect),
+    };
+    if sample_rate < 8000 {
+      return Err(InitError::SamplingRateIncorrect);
+    }
+    let song_length = (data[950] as i32 & 0x7f_i32) as isize;
+    let sequence = &data[952..];
+    let pattern_data = &data[1084..];
+    let mut state = MmC2r {
+      sample_rate,
+      channels: Default::default(),
+      src: ModSrc {
+        instruments: Vec::new(),
+        module_data: bytemuck::cast_slice(data),
+        pattern_data,
+        sequence,
+        num_patterns: Default::default(),
+        num_channels,
+        song_length,
+      },
+      playback: PlaybackState::default(),
+    };
+    state.src.num_patterns = calculate_num_patterns(state.src.module_data);
+    let mut sample_data_offset = 1084 + state.src.num_patterns * 64 * state.src.num_channels * 4;
+    let mut inst_idx = 1;
+    // First instrument is an unused dummy instrument
+    state.src.instruments.push(Instrument::dummy());
+    while inst_idx < 32 {
+      let sample_length = unsigned_short_big_endian(state.src.module_data, inst_idx * 30 + 12) * 2;
+      let fine_tune =
+        (state.src.module_data[(inst_idx * 30 + 14) as usize] as i32 & 0xf_i32) as isize;
+      let fine_tune = ((fine_tune & 0x7) - (fine_tune & 0x8) + 8) as u8;
+      let volume =
+        (state.src.module_data[(inst_idx * 30 + 15) as usize] as i32 & 0x7f_i32) as isize;
+      let volume = (if volume > 64 { 64 } else { volume }) as u8;
+      let mut loop_start = unsigned_short_big_endian(state.src.module_data, inst_idx * 30 + 16) * 2;
+      let mut loop_length =
+        unsigned_short_big_endian(state.src.module_data, inst_idx * 30 + 18) * 2;
+      if loop_start + loop_length > sample_length {
+        if loop_start / 2 + loop_length <= sample_length {
+          loop_start /= 2;
+        } else {
+          loop_length = sample_length - loop_start;
+        }
+      }
+      if loop_length < 4 {
+        loop_start = sample_length;
+        loop_length = 0;
+      }
+      let loop_start = (loop_start << 14) as usize;
+      let loop_length = (loop_length << 14) as usize;
+      let sample_data = &bytemuck::cast_slice::<u8, i8>(data)[sample_data_offset as usize..];
+      sample_data_offset += sample_length;
+      inst_idx += 1;
+      state.src.instruments.push(Instrument {
+        volume,
+        fine_tune,
+        loop_start,
+        loop_length,
+        sample_data,
+      });
+    }
+    state.playback.c2_rate = (if state.src.num_channels > 4 {
+      8363
+    } else {
+      8287
+    }) as isize;
+    state.playback.gain = (if state.src.num_channels > 4 { 32 } else { 64 }) as isize;
+    state.mute_channel(-1);
+    micromod_set_position(0, &mut state);
+    Ok(state)
+  }
+  /// Fill a buffer with delicious samples
+  pub fn get_audio(&mut self, output_buffer: &mut [i16], mut count: isize) -> bool {
+    let mut offset;
+    let mut remain;
+    let mut chan_idx;
+    if self.src.num_channels <= 0 {
+      return false;
+    }
+    offset = 0;
+    let mut cnt = true;
+    while count > 0 {
+      remain = self.playback.tick_len - self.playback.tick_offset;
+      if remain > count {
+        remain = count;
+      }
+      chan_idx = 0;
+      while chan_idx < self.src.num_channels {
+        resample(
+          &mut self.channels[chan_idx as usize],
+          output_buffer,
+          offset,
+          remain,
+          &self.src.instruments,
+        );
+        chan_idx += 1;
+      }
+      self.playback.tick_offset += remain;
+      if self.playback.tick_offset == self.playback.tick_len {
+        if sequence_tick(self) {
+          cnt = false;
+        }
+        self.playback.tick_offset = 0;
+      }
+      offset += remain;
+      count -= remain;
+    }
+    cnt
+  }
+  /// Calculate the length of the module file... In samples. Presumably.
+  pub fn calculate_mod_file_len(&self) -> Option<isize> {
+    let module_header = self.src.module_data;
+    let mut length;
+
+    let mut inst_idx;
+    let numchan = calculate_num_channels(module_header)?;
+    length = 1084 + 4 * numchan * 64 * calculate_num_patterns(module_header);
+    inst_idx = 1;
+    while inst_idx < 32 {
+      length += unsigned_short_big_endian(module_header, inst_idx * 30 + 12) * 2;
+      inst_idx += 1;
+    }
+    Some(length)
+  }
+  /// Calculate the song duration... Okay.
+  pub fn calculate_song_duration(&mut self) -> isize {
+    let mut duration;
+    duration = 0;
+    if self.src.num_channels > 0 {
+      micromod_set_position(0, self);
+      let mut song_end = false;
+      while !song_end {
+        duration += self.playback.tick_len;
+        song_end = sequence_tick(self);
+      }
+      micromod_set_position(0, self);
+    }
+    duration
+  }
+  /// Mute a channel.
+  pub fn mute_channel(&mut self, channel: isize) -> isize {
+    let mut chan_idx;
+    if channel < 0 {
+      chan_idx = 0;
+      while chan_idx < self.src.num_channels {
+        self.channels[chan_idx as usize].mute = 0;
+        chan_idx += 1;
+      }
+    } else if channel < self.src.num_channels {
+      self.channels[channel as usize].mute = 1;
+    }
+    self.src.num_channels
+  }
+  /// Set some gainz.
+  pub fn set_gain(&mut self, value: isize) {
+    self.playback.gain = value;
+  }
+}
+
+fn micromod_set_position(mut pos: isize, state: &mut MmC2r) {
+  let mut chan_idx;
+  let mut chan;
+  if state.src.num_channels <= 0 {
+    return;
+  }
+  if pos >= state.src.song_length {
+    pos = 0;
+  }
+  state.playback.break_pattern = pos;
+  state.playback.next_row = 0;
+  state.playback.tick = 1;
+  state.playback.speed = 6;
+  set_tempo(125, &mut state.playback.tick_len, state.sample_rate);
+  state.playback.pl_channel = -1;
+  state.playback.pl_count = state.playback.pl_channel;
+  state.playback.random_seed = 0xabcdef;
+  chan_idx = 0;
+  while chan_idx < state.src.num_channels {
+    chan = &mut state.channels[chan_idx as usize];
+    chan.id = chan_idx as u8;
+    let fresh15 = &mut chan.assigned;
+    *fresh15 = 0;
+    chan.instrument = *fresh15;
+    chan.volume = 0;
+    match chan_idx & 0x3 {
+      0 | 3 => {
+        chan.panning = 0;
+      }
+      1 | 2 => {
+        chan.panning = 127;
+      }
+      _ => {}
+    }
+    chan_idx += 1;
+  }
+  sequence_tick(state);
+  state.playback.tick_offset = 0;
+}