Add boot record abstraction and MBR implementation

inc/kernel/filesystem/bootrecords.h

@@ -0,0 +1,65 @@
+#pragma once
+#include <stdint.h>
+#include <stddef.h>
+
+/************************
+ *** Team Kitty, 2021 ***
+ ***     Chroma       ***
+ ***********************/
+
+/**
+ * @brief Abstract class for partition table implementations.
+ * The partition table implements a way to store and handle the boot record for any system.
+ * ! Do not instantiate!
+ */
+class BasePartitionTable {
+public:
+
+    // Initialize the partition object
+    virtual void Init() = 0;
+
+    // Get the amount of partitions in the table
+    virtual uint8_t GetPartitions() = 0;
+
+    // Get the offset which, when added to the start of the disk, will provide the start of the given partition.
+    virtual size_t GetPartitionStart(uint8_t PartitionID) = 0;
+    // Get the length of the given partition on disk.
+    virtual size_t GetPartitionSize(uint8_t PartitionID) = 0;
+
+private:
+
+    static BasePartitionTable* Primary;
+};
+
+
+/**
+ * @brief A BasePartitionTable implementation for MBR (BIOS) systems.
+ */
+class MBRPartitionTable : public BasePartitionTable {
+public:
+
+    // Initialize the partition object
+    virtual void Init() override;
+
+    // Get the amount of partitions in the table
+    virtual uint8_t GetPartitions() override;
+
+    // Get the offset which, when added to the start of the disk, will provide the start of the given partition.
+    virtual size_t GetPartitionStart(uint8_t PartitionID) override;
+    // Get the length of the given partition on disk.
+    virtual size_t GetPartitionSize(uint8_t PartitionID) override;
+
+private:
+
+    // An MBR Partition Table Entry
+    struct MBREntry {
+        uint8_t Status;         // 0x80 for "active", 0x00 for inactive, all other values are invalid.
+        uint8_t CHS_First[3];   // Cylinder-Head-Sector address of the first sector in this partition.
+        uint8_t Type;           // Partition type. https://en.wikipedia.org/wiki/Partition_type
+        uint8_t CHS_Last[3];    // Cylinder-Head-Sector address of the last sector in this partition.
+        uint32_t LBA_First;     // LBA of the first sector in this partition
+        uint32_t SectorCount;   // Total count of sectors in this partition
+    } __attribute__((packed));
+
+    MBREntry* Entries;
+};

inc/kernel/filesystem/filesystem.h

@@ -13,7 +13,7 @@
  * ! Do not instantiate!
  */
 
-class FileSystem {
+class BaseFileSystem {
 public:
     virtual void Init(size_t Sector, size_t Size) = 0;
     virtual const char* GetName() = 0;