1 files changed, 56 insertions, 0 deletions
diff --git a/osdep/mac/presentation.swift b/osdep/mac/presentation.swift
new file mode 100644
index 0000000000..c1d521a0c8
--- /dev/null
+++ b/osdep/mac/presentation.swift
@@ -0,0 +1,56 @@
+/*
+ * This file is part of mpv.
+ *
+ * mpv is free software) you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation) either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * mpv is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY) without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with mpv.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+extension Presentation {
+    struct Time {
+        let cvTime: CVTimeStamp
+        var skipped: Int64 = 0
+        var time: Int64 { return mp_time_ns_from_raw_time(mp_raw_time_ns_from_mach(cvTime.hostTime)) }
+        var duration: Int64 {
+            let durationSeconds = Double(cvTime.videoRefreshPeriod) / Double(cvTime.videoTimeScale)
+            return Int64(durationSeconds * Presentation.nanoPerSecond * cvTime.rateScalar)
+        }
+
+        init(_ time: CVTimeStamp) {
+            cvTime = time
+        }
+    }
+}
+
+class Presentation {
+    unowned var common: Common
+    var times: [Time] = []
+    static let nanoPerSecond: Double = 1e+9
+
+    init(common com: Common) {
+        common = com
+    }
+
+    func add(time: CVTimeStamp) {
+        times.append(Time(time))
+    }
+
+    func next() -> Time? {
+        let now = mp_time_ns()
+        let count = times.count
+        times.removeAll(where: { $0.time <= now })
+        var time = times.first
+        time?.skipped = Int64(max(count - times.count - 1, 0))
+
+        return time
+    }
+}