1 files changed, 99 insertions, 0 deletions

diff --git a/src/core/hle/kernel/k_page_group.h b/src/core/hle/kernel/k_page_group.h
new file mode 100644
index 000000000..968753992
--- /dev/null
+++ b/src/core/hle/kernel/k_page_group.h
@@ -0,0 +1,99 @@
+// SPDX-FileCopyrightText: Copyright 2020 yuzu Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <list>
+
+#include "common/assert.h"
+#include "common/common_types.h"
+#include "core/hle/kernel/memory_types.h"
+#include "core/hle/result.h"
+
+namespace Kernel {
+
+class KPageGroup final {
+public:
+    class Node final {
+    public:
+        constexpr Node(u64 addr_, std::size_t num_pages_) : addr{addr_}, num_pages{num_pages_} {}
+
+        constexpr u64 GetAddress() const {
+            return addr;
+        }
+
+        constexpr std::size_t GetNumPages() const {
+            return num_pages;
+        }
+
+        constexpr std::size_t GetSize() const {
+            return GetNumPages() * PageSize;
+        }
+
+    private:
+        u64 addr{};
+        std::size_t num_pages{};
+    };
+
+public:
+    KPageGroup() = default;
+    KPageGroup(u64 address, u64 num_pages) {
+        ASSERT(AddBlock(address, num_pages).IsSuccess());
+    }
+
+    constexpr std::list<Node>& Nodes() {
+        return nodes;
+    }
+
+    constexpr const std::list<Node>& Nodes() const {
+        return nodes;
+    }
+
+    std::size_t GetNumPages() const {
+        std::size_t num_pages = 0;
+        for (const Node& node : nodes) {
+            num_pages += node.GetNumPages();
+        }
+        return num_pages;
+    }
+
+    bool IsEqual(KPageGroup& other) const {
+        auto this_node = nodes.begin();
+        auto other_node = other.nodes.begin();
+        while (this_node != nodes.end() && other_node != other.nodes.end()) {
+            if (this_node->GetAddress() != other_node->GetAddress() ||
+                this_node->GetNumPages() != other_node->GetNumPages()) {
+                return false;
+            }
+            this_node = std::next(this_node);
+            other_node = std::next(other_node);
+        }
+
+        return this_node == nodes.end() && other_node == other.nodes.end();
+    }
+
+    Result AddBlock(u64 address, u64 num_pages) {
+        if (!num_pages) {
+            return ResultSuccess;
+        }
+        if (!nodes.empty()) {
+            const auto node = nodes.back();
+            if (node.GetAddress() + node.GetNumPages() * PageSize == address) {
+                address = node.GetAddress();
+                num_pages += node.GetNumPages();
+                nodes.pop_back();
+            }
+        }
+        nodes.push_back({address, num_pages});
+        return ResultSuccess;
+    }
+
+    bool Empty() const {
+        return nodes.empty();
+    }
+
+private:
+    std::list<Node> nodes;
+};
+
+} // namespace Kernel