WIP: Memory mapper.

* Bumped required C++ version up to C++17.
    * Memory mapper has barebones functionality.
    * Base memory virtual class added. No implementations have been written yet.

CMakeLists.txt

@@ -4,7 +4,7 @@ set(gui_name "plip-sdl")
 set(lib_name "plip")
 
 project(${gui_name})
-set(CMAKE_CXX_STANDARD 14)
+set(CMAKE_CXX_STANDARD 17)
 
 find_package(SDL2 REQUIRED)
 
@@ -35,6 +35,7 @@ add_library(${lib_name}
         libplip/Plip.cpp
         libplip/PlipInput.cpp
         libplip/PlipInputDefinition.cpp
+        libplip/PlipMemoryMap.cpp
 )
 
 add_dependencies(${lib_name} GENERATE_LIB_VERSION_HEADER)

libplip/PlipMemory.h

@@ -0,0 +1,24 @@
+/* PlipMemory.h
+ *
+ * An interface representing some type of memory.
+ */
+
+#pragma once
+
+#include <cstdint>
+
+namespace Plip {
+    class PlipMemory {
+    public:
+        uint8_t operator[] (uint32_t offset) {
+            return GetByte(offset);
+        };
+
+        virtual uint8_t GetByte(uint32_t address) = 0;
+        virtual uint32_t GetLength() = 0;
+        virtual void SetByte(uint32_t address, uint8_t value) = 0;
+
+    protected:
+        PlipMemory() = default;
+    };
+}

libplip/PlipMemoryMap.cpp

@@ -0,0 +1,58 @@
+/* PlipMemoryMap.cpp
+ *
+ * A flexible memory mapper.
+ */
+
+#include <tuple>
+
+#include "PlipMemoryMap.h"
+
+namespace Plip {
+    void PlipMemoryMap::AddBlock(PlipMemory *memory, uint32_t offset, uint32_t length) {
+        uint32_t start = 0;
+
+        if(m_range.begin() != m_range.end()) {
+            auto last = m_range.back();
+            start = last.startAddress + last.length;
+        }
+
+        m_range.push_back({
+            .startAddress = start,
+            .memory = memory,
+            .offset = offset,
+            .length = length
+        });
+    }
+
+    std::tuple<PlipMemory*, uint32_t> PlipMemoryMap::FindAddress(uint32_t address) {
+        for(auto const &memory : m_range) {
+            if(address < memory.startAddress || address > memory.startAddress + memory.length)
+                continue;
+
+            return { memory.memory, address - memory.startAddress };
+        }
+
+        return { nullptr, 0 };
+    }
+
+    uint8_t PlipMemoryMap::GetByte(uint32_t address) {
+        auto [ memory, offset ] = FindAddress(address);
+
+        if(memory == nullptr) return 0;
+        return memory->GetByte(offset);
+    }
+
+    uint32_t PlipMemoryMap::GetLength() {
+        if(m_range.begin() == m_range.end()) return 0;
+
+        auto last = m_range.back();
+        return last.startAddress + last.length;
+    }
+
+    void PlipMemoryMap::SetByte(uint32_t address, uint8_t value) {
+        auto [ memory, offset ] = FindAddress(address);
+
+        if(memory == nullptr) return;
+        memory->SetByte(offset, value);
+    }
+}

libplip/PlipMemoryMap.h

@@ -0,0 +1,33 @@
+/* PlipMemoryMap.h
+ *
+ * A flexible memory mapper.
+ */
+
+#pragma once
+
+#include <cstdint>
+#include <list>
+
+#include "PlipMemory.h"
+
+namespace Plip {
+    struct PlipMemoryMapRange {
+        uint32_t startAddress;
+        PlipMemory *memory;
+        uint32_t offset;
+        uint32_t length;
+    };
+
+    class PlipMemoryMap {
+    public:
+        void AddBlock(PlipMemory *memory, uint32_t offset, uint32_t length);
+        uint8_t GetByte(uint32_t address);
+        uint32_t GetLength();
+        void SetByte(uint32_t address, uint8_t value);
+
+    private:
+        std::tuple<PlipMemory*, uint32_t> FindAddress(uint32_t address);
+
+        std::list<PlipMemoryMapRange> m_range;
+    };
+}