Use nom to parse instrument data.

Cargo.lock

@@ -2,6 +2,31 @@
 # It is not intended for manual editing.
 version = 3
 
+[[package]]
+name = "memchr"
+version = "2.7.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "523dc4f511e55ab87b694dc30d0f820d60906ef06413f93d4d7a1385599cc149"
+
+[[package]]
+name = "minimal-lexical"
+version = "0.2.1"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "68354c5c6bd36d73ff3feceb05efa59b6acb7626617f4962be322a825e61f79a"
+
+[[package]]
+name = "nom"
+version = "7.1.3"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "d273983c5a657a70a3e8f2a01329822f3b8c8172b73826411a55751e404a0a4a"
+dependencies = [
+ "memchr",
+ "minimal-lexical",
+]
+
 [[package]]
 name = "slamshuffle"
 version = "0.1.0"
+dependencies = [
+ "nom",
+]

Cargo.toml

@@ -7,3 +7,4 @@ license = "MIT"
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
 [dependencies]
+nom = "7"

src/instruments.rs

@@ -0,0 +1,58 @@
+use nom::{
+    bytes::complete::tag_no_case,
+    character::complete::{hex_digit1, line_ending, not_line_ending, space1},
+    combinator::{map_parser, map_res, opt},
+    error::{Error, ErrorKind},
+    multi::fold_many0,
+    sequence::{preceded, separated_pair, terminated},
+    IResult,
+};
+
+#[derive(Default)]
+pub struct InstrumentSet([u8; 32]);
+
+impl InstrumentSet {
+    pub fn generate(input: &str) -> Self {
+        match Self::parse(input) {
+            Ok((_, set)) => set,
+            Err(_) => panic!(),
+        }
+    }
+
+    fn parse<'i>(input: &'i str) -> IResult<&'i str, Self> {
+        fold_many0(
+            terminated(
+                opt(preceded(
+                    tag_no_case("#WAVE"),
+                    map_parser(not_line_ending, wave_numbers),
+                )),
+                line_ending,
+            ),
+            Self::default,
+            |mut set, bytes: Option<(usize, u8)>| match bytes {
+                Some((slot, sample)) => {
+                    let pos = slot - 0x20;
+                    set.0[pos] = sample;
+                    set
+                }
+                None => set,
+            },
+        )(input)
+    }
+}
+
+fn wave_numbers(input: &str) -> IResult<&str, (usize, u8)> {
+    separated_pair(
+        map_res(hex_digit1, |s: &str| {
+            s.parse::<usize>().map_err(|_| nom::error::make_error::<&str, Error<&str>>(s, ErrorKind::HexDigit)).and_then(|n| {
+                if (0x20..0x30).contains(&n) {
+                    Ok(n)
+                } else {
+                    Err(nom::error::make_error(s, ErrorKind::MapRes))
+                }
+            })
+        }),
+        space1,
+        map_res(hex_digit1, |s: &str| s.parse::<u8>()),
+    )(input)
+}

src/lib.rs

@@ -1 +1,2 @@
+pub mod instruments;
 pub mod mfvi;