Initial pass at Locator.Locations.time

Author: domkm

Sources/Shared/Publication/Extensions/Audio/Locator+Audio.swift

@@ -0,0 +1,73 @@
+//
+//  Copyright 2024 Readium Foundation. All rights reserved.
+//  Use of this source code is governed by the BSD-style license
+//  available in the top-level LICENSE file of the project.
+//
+
+import Foundation
+
+/// Audio extensions for `Locator.Locations`.
+public extension Locator.Locations {
+  enum TimeFragment: Equatable, Sendable {
+    case offset(Double)
+    case duration(Double)
+    case range(Double, Double)
+
+    init?(offset: Double?, duration: Double?) {
+      switch (offset, duration) {
+      case let (.some(offset), .some(duration)):
+        self = .range(offset, duration)
+      case let (.some(offset), .none):
+        self = .offset(offset)
+      case let (.none, .some(duration)):
+        self = .duration(duration)
+      case (.none, .none):
+        return nil
+      }
+    }
+
+    public var offset: Double? {
+      switch self {
+      case let .offset(offset):
+        return offset
+      case let .range(offset, _):
+        return offset
+      default:
+        return nil
+      }
+    }
+
+    public var duration: Double? {
+      switch self {
+      case let .duration(duration):
+        return duration
+      case let .range(_, duration):
+        return duration
+      default:
+        return nil
+      }
+    }
+  }
+
+  private static let timeFragmentRegex = try! NSRegularExpression(pattern: #"t=([^,]*),?([^,]*)"#)
+
+  var time: TimeFragment? {
+    for fragment in fragments {
+      let range = NSRange(fragment.startIndex ..< fragment.endIndex, in: fragment)
+      if let match = Self.timeFragmentRegex.firstMatch(in: fragment, range: range) {
+        let group1NSRange = match.range(at: 1)
+        let group2NSRange = match.range(at: 2)
+        var offset: Double?
+        var duration: Double?
+        if group1NSRange.location != NSNotFound, let group1Range = Range(group1NSRange, in: fragment) {
+          offset = Double(fragment[group1Range])
+        }
+        if group2NSRange.location != NSNotFound, let group2Range = Range(group2NSRange, in: fragment) {
+          duration = Double(fragment[group2Range])
+        }
+        return TimeFragment(offset: offset, duration: duration)
+      }
+    }
+    return nil
+  }
+}

Tests/SharedTests/Publication/Extensions/Audio/Locator+AudioTests.swift

@@ -0,0 +1,43 @@
+//
+//  Copyright 2024 Readium Foundation. All rights reserved.
+//  Use of this source code is governed by the BSD-style license
+//  available in the top-level LICENSE file of the project.
+//
+
+@testable import R2Shared
+import XCTest
+
+class LocatorLocationsAudioTests: XCTestCase {
+  func testNoFragment() {
+    XCTAssertNil(Locator.Locations().time)
+  }
+
+  func testMalformedFragment() {
+    XCTAssertNil(Locator.Locations(fragments: ["t=one"]).time)
+  }
+
+  func testValidFragments() {
+    continueAfterFailure = false
+    for offsetStr in ["", "1", "1.0", "1.1"] {
+      for durationStr in ["", ",", ",1", ",1.0", ",1.1"] {
+        let val = offsetStr + durationStr
+        if val == "" || val == "," {
+          continue
+        }
+        let locations = Locator.Locations(fragments: ["t=\(val)"])
+        let time = locations.time
+        switch time {
+        case let .offset(offset):
+          XCTAssertEqual(offset, Double(offsetStr))
+        case let .duration(duration):
+          XCTAssertEqual(duration, Double(durationStr.replacingPrefix(",", by: "")))
+        case let .range(offset, duration):
+          XCTAssertEqual(offset, Double(offsetStr))
+          XCTAssertEqual(duration, Double(durationStr.replacingPrefix(",", by: "")))
+        case nil:
+          XCTAssertNotNil(time)
+        }
+      }
+    }
+  }
+}