#12 Reading Replay Gain metadata from Cue sheets

Source/Core/LibCue/LibCueMapper.swift

@@ -77,6 +77,9 @@ class LibCueMapper {
         metadata.genre = cd.genre
         metadata.date = cd.date
 
+        metadata.replayGain = .init(albumGain: cd.replayGain_albumGain,
+                                    albumPeak: cd.replayGain_albumPeak)
+
         return metadata
     }
 
@@ -89,6 +92,11 @@ class LibCueMapper {
         metadata.genre = cd.genre
         metadata.date = cd.date
 
+        metadata.replayGain = .init(trackGain: track.replayGain_trackGain,
+                                    trackPeak: track.replayGain_trackPeak,
+                                    albumGain: cd.replayGain_albumGain,
+                                    albumPeak: cd.replayGain_albumPeak)
+
         metadata.artist = track.performer
         metadata.title = track.title
         metadata.composer = track.composer

Source/Core/LibCue/Wrappers/LibCueCD.swift

@@ -14,8 +14,27 @@ class LibCueCD {
 
     let file: URL
 
-    let rems: [LibCueREM]
-    lazy var date: String? = rems.first(where: {$0.type == .date})?.value
+    let rems: [LibCueREMType: LibCueREM]
+
+    lazy var date: String? = rems[.date]?.value
+
+    lazy var replayGain_albumGain: Float? = {
+
+        if let gainStr = self.rems[.replayGain_albumGain]?.value.lowerCasedAndTrimmed().removingOccurrences(of: "db") {
+            return Float(gainStr)
+        }
+
+        return nil
+    }()
+
+    lazy var replayGain_albumPeak: Float? = {
+
+        if let gainStr = self.rems[.replayGain_albumPeak]?.value.trim() {
+            return Float(gainStr)
+        }
+
+        return nil
+    }()
 
     let cdTexts: [LibCueCDText]
     lazy var title: String? = cdTexts.first(where: {$0.pti == .title})?.value
@@ -67,12 +86,16 @@ class LibCueCD {
 
         if let remPtr = cd_get_rem(cdPtr) {
 
-            self.rems = LibCueREMType.allCases.compactMap {remType in
-                LibCueREM(type: remType, pointer: remPtr)
+            var map: [LibCueREMType: LibCueREM] = [:]
+
+            LibCueREMType.allCases.forEach {remType in
+                map[remType] = LibCueREM(type: remType, pointer: remPtr)
             }
 
+            self.rems = map
+
         } else {
-            self.rems = []
+            self.rems = [:]
         }
     }
 }

Source/Core/LibCue/Wrappers/LibCueREM.swift

@@ -26,18 +26,15 @@ class LibCueREM {
 
 enum LibCueREMType: CaseIterable {
 
-//    REM_DATE,    /* date of cd/track */
-//    REM_REPLAYGAIN_ALBUM_GAIN,
-//    REM_REPLAYGAIN_ALBUM_PEAK,
-//    REM_REPLAYGAIN_TRACK_GAIN,
-//    REM_REPLAYGAIN_TRACK_PEAK,
-//    REM_END        /* terminating REM (for stepping through REMs) */
-
-    case date, end
+    case date, replayGain_albumGain, replayGain_albumPeak, replayGain_trackGain, replayGain_trackPeak, end
 
     private static var mappings: [RemType: LibCueREMType] = [
 
         REM_DATE: .date,
+        REM_REPLAYGAIN_ALBUM_GAIN: .replayGain_albumGain,
+        REM_REPLAYGAIN_ALBUM_PEAK: .replayGain_albumPeak,
+        REM_REPLAYGAIN_TRACK_GAIN: .replayGain_trackGain,
+        REM_REPLAYGAIN_TRACK_PEAK: .replayGain_trackPeak,
         REM_END: .end
     ]
 
@@ -46,7 +43,27 @@ enum LibCueREMType: CaseIterable {
     }
 
     var remType: RemType {
-        return self == .date ? REM_DATE : REM_END
+
+        switch self {
+
+        case .date:
+            return REM_DATE
+
+        case .replayGain_albumGain:
+            return REM_REPLAYGAIN_ALBUM_GAIN
+
+        case .replayGain_albumPeak:
+            return REM_REPLAYGAIN_ALBUM_PEAK
+
+        case .replayGain_trackGain:
+            return REM_REPLAYGAIN_TRACK_GAIN
+
+        case .replayGain_trackPeak:
+            return REM_REPLAYGAIN_TRACK_PEAK
+
+        case .end:
+            return REM_END
+        }
     }
 }
 

Source/Core/LibCue/Wrappers/LibCueTrack.swift

@@ -23,8 +23,26 @@ class LibCueTrack {
     let preGap: Double?
     let postGap: Double?
 
-    let rems: [LibCueREM]
-    lazy var date: String? = rems.first(where: {$0.type == .date})?.value
+    let rems: [LibCueREMType: LibCueREM]
+    lazy var date: String? = rems[.date]?.value
+
+    lazy var replayGain_trackGain: Float? = {
+
+        if let gainStr = self.rems[.replayGain_trackGain]?.value.lowerCasedAndTrimmed().removingOccurrences(of: "db") {
+            return Float(gainStr)
+        }
+
+        return nil
+    }()
+
+    lazy var replayGain_trackPeak: Float? = {
+
+        if let gainStr = self.rems[.replayGain_trackPeak]?.value.trim() {
+            return Float(gainStr)
+        }
+
+        return nil
+    }()
 
     let cdTexts: [LibCueCDText]
     lazy var title: String? = cdTexts.first(where: {$0.pti == .title})?.value
@@ -80,12 +98,16 @@ class LibCueTrack {
 
         if let remPtr = track_get_rem(pointer) {
 
-            self.rems = LibCueREMType.allCases.compactMap {remType in
-                LibCueREM(type: remType, pointer: remPtr)
+            var map: [LibCueREMType: LibCueREM] = [:]
+
+            LibCueREMType.allCases.forEach {remType in
+                map[remType] = LibCueREM(type: remType, pointer: remPtr)
             }
 
+            self.rems = map
+
         } else {
-            self.rems = []
+            self.rems = [:]
         }
     }
 }

Source/Core/Playlist/ImportExport/FileSystemPlaylist.swift

@@ -39,7 +39,9 @@ class CueSheetMetadata: Codable {
     var date: String?
     var discID: String?
     var comment: String?
-
+
+    var replayGain: ReplayGain?
+
     // Track-specific info
 
     var title: String?

Source/Core/TrackIO/Model/ReplayGain.swift

@@ -10,7 +10,7 @@
 
 import Foundation
 
-struct ReplayGain {
+struct ReplayGain: Codable {
 
     let trackGain: Float?
     let trackPeak: Float?

Source/Core/TrackIO/Model/Track.swift

@@ -202,7 +202,7 @@ class Track: Hashable, PlaylistItem, PlayableItem {
             auxiliaryMetadata[theKey] = MetadataEntry(format: .other, key: theKey, value: value)
         }
 
-        self.replayGain = metadata.replayGain
+        self.replayGain = metadata.replayGain ?? cueSheetMetadata?.replayGain
     }
 
     private func correctChapterTimes() {