1 files changed, 47 insertions, 0 deletions

diff --git a/src/core/hle/service/hid/irs_ring_lifo.h b/src/core/hle/service/hid/irs_ring_lifo.h
new file mode 100644
index 000000000..a31e61037
--- /dev/null
+++ b/src/core/hle/service/hid/irs_ring_lifo.h
@@ -0,0 +1,47 @@
+// SPDX-FileCopyrightText: Copyright 2022 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-3.0-or-later
+
+#pragma once
+
+#include <array>
+
+#include "common/common_types.h"
+
+namespace Service::IRS {
+
+template <typename State, std::size_t max_buffer_size>
+struct Lifo {
+    s64 sampling_number{};
+    s64 buffer_count{};
+    std::array<State, max_buffer_size> entries{};
+
+    const State& ReadCurrentEntry() const {
+        return entries[GetBufferTail()];
+    }
+
+    const State& ReadPreviousEntry() const {
+        return entries[GetPreviousEntryIndex()];
+    }
+
+    s64 GetBufferTail() const {
+        return sampling_number % max_buffer_size;
+    }
+
+    std::size_t GetPreviousEntryIndex() const {
+        return static_cast<size_t>((GetBufferTail() + max_buffer_size - 1) % max_buffer_size);
+    }
+
+    std::size_t GetNextEntryIndex() const {
+        return static_cast<size_t>((GetBufferTail() + 1) % max_buffer_size);
+    }
+
+    void WriteNextEntry(const State& new_state) {
+        if (buffer_count < max_buffer_size) {
+            buffer_count++;
+        }
+        sampling_number++;
+        entries[GetBufferTail()] = new_state;
+    }
+};
+
+} // namespace Service::IRS