fretboard: NonZeroU8

Author: algorithmiker

src/backend/errors/backend_error_kind.rs

@@ -32,7 +32,7 @@ impl BackendErrorKind {
             BackendErrorKind::Parse3InvalidCharacter(c) => {
                 ("Invalid character".into(), match c {
                     Some(c) => format!("The character {c} is not valid here."),
-                    None => format!("This character is not valid here."),
+                    None => "This character is not valid here.".to_string(),
                 })
             }
             BackendErrorKind::FixupFailed => (

src/backend/muxml/fretboard.rs

@@ -1,4 +1,4 @@
-use crate::backend::errors::backend_error::BackendError;
+use std::num::NonZeroU8;
 
 const NOTE2_STEPS: [(char, bool); 12] = [
     ('C', false),
@@ -36,18 +36,14 @@ impl MuxmlNote2 {
 }
 
 // TODO: make this panic an error
-pub fn get_fretboard_note2(string: char, fret: u8) -> Result<MuxmlNote2, BackendError> {
-    Ok(MuxmlNote2 {
-        step: STRING_BASE_NOTES[string as usize]
-            .unwrap_or_else(|| panic!("Don't know base note for string {string}"))
-            + fret,
-        dead: false,
-    })
+pub fn get_fretboard_note2(string: char, fret: u8) -> Option<MuxmlNote2> {
+    let base = (*STRING_BASE_NOTES.get(string as usize)?)?;
+    Some(MuxmlNote2 { step: base.get() + fret, dead: false })
 }
 
 /// TODO: benchmark this against a match and a hashmap, a hashmap will be probably faster as it can
 /// stay in cache (we need a total of max 16 base notes*1 byte => 16bytes which is less than a
 /// cache line
 /// Generated by tools/gen_note_lookup.rs
 #[rustfmt::skip]
-const STRING_BASE_NOTES: [Option<u8>;256]= [None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, Some(45), Some(59), None, Some(50), Some(40), None, Some(55), None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, Some(64), None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None];
+const STRING_BASE_NOTES: [Option<NonZeroU8>;256] = [None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, Some(NonZeroU8::new(45).unwrap()), Some(NonZeroU8::new(49).unwrap()), None, Some(NonZeroU8::new(50).unwrap()), Some(NonZeroU8::new(40).unwrap()), None, Some(NonZeroU8::new(55).unwrap()), None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, Some(NonZeroU8::new(62).unwrap()), Some(NonZeroU8::new(64).unwrap()), None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None, None];

src/backend/muxml/mod.rs

@@ -99,7 +99,10 @@ impl Muxml2TabElement {
                     }) else {
                         continue;
                     };
-                    let note = get_fretboard_note2(parsed.base_notes[elem_idx % 6], fret).unwrap();
+                    let string_name = parsed.base_notes[elem_idx % 6];
+                    let note = get_fretboard_note2(string_name, fret).unwrap_or_else(|| {
+                        panic!("Don't know base note for string name {string_name}",)
+                    });
                     let (step, octave, sharp) = note.step_octave_sharp();
                     let properties = note_properties.get(&(elem_idx as u32));
                     write_muxml2_note(buf, step, octave, sharp, need_chord, dead, properties)?;

tools/gen_note_lookup.rs

@@ -1,7 +1,8 @@
+use std::num::NonZeroU8;
 fn main() {
-    let mut lookup = [None; 256];
+    let mut lookup = vec![String::from("None"); 256];
     let mut set_lookup = |c: char, value: u8| {
-        lookup[c as usize] = Some(value);
+        lookup[c as usize] = format!("Some(NonZeroU8::new({value}).unwrap())");
     };
 
     set_lookup('E', 3 * 12 + 4);
@@ -11,9 +12,16 @@ fn main() {
     set_lookup('B', 4 * 12 + 1);
     set_lookup('d', 5 * 12 + 2);
     set_lookup('e', 5 * 12 + 4);
-
+    let mut b = String::from("[");
+    for x in &lookup {
+        b.push_str(&x.to_string());
+        b.push_str(", ");
+    }
+    b.pop();
+    b.pop();
+    b.push(']');
     println!(
-        "#[rustfmt::skip]\nconst STRING_BASE_NOTES: [Option<u8>;{}] ={lookup:?};",
+        "#[rustfmt::skip]\nconst STRING_BASE_NOTES: [Option<NonZeroU8>;{}] = {b};",
         lookup.len()
     );
 }