Types

flake.nix

@@ -26,6 +26,7 @@
           shellHook = ''
             echo "Entering Nix shell with Lean and VS Code..."
             export PS1="\[\e[1;32m\][nix-shell:\w]$\[\e[m\] "
+            export PATH="$PWD/.lake/build/bin:$PATH"
           '';
         };
     in

src/Ep133.lean

@@ -0,0 +1,4 @@
+
+import Ep133.Parsing
+import Ep133.Types
+import Ep133.Util

src/Ep133/Parsing.lean

@@ -0,0 +1,112 @@
+
+import Ep133.Types
+import Ep133.Util
+
+
+open Ep133.Types
+open Ep133.Util (getFloat32BE getUInt32 require)
+
+open ParseResult (throw)
+
+
+-- See <https://github.com/phones24/ep133-export-to-daw/blob/99454368f8da44b8b5bf495df0f89c72603b8dc4/docs/EP133_FORMATS.md> for reference.
+
+namespace Ep133.Parsing
+
+
+def parseEffects (raw : ByteArray) : ParseResult Effects :=
+  do
+   require (raw.size >= 100)
+      $ throw ("Effects only contains " ++ toString raw.size ++ " bytes.")
+    let effectType := raw[4]!
+    let active ← EffectLabel.ofUInt8 effectType
+    let effects ←
+      (List.range 7).mapM
+        (fun i ↦
+          do
+            let label ← EffectLabel.ofUInt8 i.toUInt8
+            let param1 := getFloat32BE raw $ 8 + 4 * i
+            let param2 := getFloat32BE raw $ 72 + 4 * i
+            pure ⟨ label , {param1, param2} ⟩
+        )
+    pure
+      {
+        raw
+      , active
+      , effects := Std.HashMap.ofList effects
+      }
+
+
+def makePatternLabel (l : Fin 4) (n : UInt8) : ParseResult PatternLabel :=
+  do
+    require (n > 0 && n < 100)
+      $ throw ("Pattern " ++ toString n ++ " is out of range.")
+    pure {letter := l, number := Fin.ofNat 99 $ n.toNat - 1}
+
+
+def parseScene (raw : ByteArray) (offset : Nat) : ParseResult Scene :=
+  do
+    let patternA ← makePatternLabel 0 $ raw[offset + 0]!
+    let patternB ← makePatternLabel 1 $ raw[offset + 1]!
+    let patternC ← makePatternLabel 2 $ raw[offset + 2]!
+    let patternD ← makePatternLabel 3 $ raw[offset + 3]!
+    pure
+      {
+        patternA, patternB, patternC, patternD
+      , timeSignature := {numerator := raw[offset + 4]!.toNat, denominator := raw[offset + 5]!.toNat}
+      }
+
+
+def parseScenes (raw : ByteArray) : ParseResult Scenes :=
+  do
+    require (raw.size >= 605)
+      $ throw ("Scenes only contains " ++ toString raw.size ++ " bytes.")
+    let sceneCount := raw[604]! |> UInt8.toNat
+    let scenes : List Scene ← (List.range sceneCount).mapM (fun n ↦ parseScene raw (1 + 6 * n))
+    pure
+      {
+        raw
+      , scenes := scenes.toArray
+      }
+
+
+def parsePad (raw : ByteArray) : ParseResult Pad :=
+  do
+    require (raw.size = 26)
+      $ throw ("Pad contains " ++ toString raw.size ++ " bytes instead of 27.")
+    let playMode ← PlayMode.ofUInt8 raw[23]!
+    let volume ← Volume.ofUInt8 raw[16]!
+    let timeStretchMode ← TimeStretchMode.ofUInt8 raw[21]!
+    let timeStretchBars ← TimeStretchBars.ofUInt8 raw[25]!
+    let chokeGroup ← ChokeGroup.ofUInt8 raw[22]!
+    let soundId ← SoundId.ofUInt8s raw[2]! raw[1]!
+    let pan ← Pan.ofUInt8 raw[18]!
+    let trim :=
+      {
+        left := getUInt32 0 raw[6]! raw[5]! raw[4]! |> UInt32.toNat
+        right := getUInt32 0 raw[10]! raw[9]! raw[8]! |> UInt32.toNat
+      }
+    let pitch ← Pitch.ofUInt8s raw[17]! 0  -- raw[26]!
+    pure
+      {
+        raw
+      , soundId
+      , volume
+      , attack := raw[19]!
+      , release := raw[20]!
+      , playMode
+      , timeStretch :=
+          {
+            mode := timeStretchMode
+          , bars:= timeStretchBars
+          , bpm := getFloat32BE raw 12
+          }
+      , pitch
+      , trim
+      , pan
+      , chokeGroup
+      , midiChannel := raw[3]!
+      }
+
+
+end Ep133.Parsing