Get rough shape of CD file processing code

src/Library/include/CD/cd_internal.hpp

@@ -5,7 +5,61 @@
 namespace JabyEngine {
     namespace CD {
         namespace internal {
+            enum struct State {
+                Free = 0,
+                Done = 0,
+
+                Reading,
+                BufferFull,
+                Error,
+            };
+
             extern VolatilePOD<CD_IO::Interrupt::Type> last_interrupt;
+            extern VolatilePOD<State>                  state;
+
+            struct Sector {
+                uint32_t data[512];
+            };
+
+            struct FileInfo {
+                uint16_t lba;
+                uint16_t sectors;
+
+                constexpr FileInfo(uint16_t lba, uint16_t sectors) : lba(lba), sectors(sectors) {
+                }
+            };
+
+            class SectorBufferAllocator {
+            private:
+                struct Dummy {
+                };
+
+                typedef Sector* (*SimpleAllocator)();
+                typedef Sector* (Dummy::*ComplexAllocator)();
+
+            private:
+                Dummy* this_ctx = nullptr;
+                union {
+                    SimpleAllocator allocate;
+                    ComplexAllocator this_allocate;
+                };
+
+                SectorBufferAllocator(SimpleAllocator allocate) : this_ctx(nullptr), allocate(allocate) {
+                }
+
+                SectorBufferAllocator(Dummy* ctx, ComplexAllocator this_allocate) : this_ctx(ctx), this_allocate(this_allocate) {
+                }
+
+            public:
+                static SectorBufferAllocator create(SimpleAllocator allocate) {
+                    return SectorBufferAllocator(allocate);
+                }
+
+                template<typename T>
+                static SectorBufferAllocator create(T &obj, Sector* (T::*obj_allocate)()) {
+                    return SectorBufferAllocator(reinterpret_cast<Dummy*>(&obj), reinterpret_cast<ComplexAllocator>(obj_allocate));
+                }
+            };
 
             struct Command {
                 static void wait_until(CD_IO::Interrupt::Type irq) {
@@ -26,6 +80,8 @@ namespace JabyEngine {
                     wait_until(cmd.complete_irq);
                 }
             };
+
+            State start_reading(FileInfo file_info, const SectorBufferAllocator& buffer_allocator);
         }
     }
 }