Kernel: Split the FATFileSystem.{cpp,h} files into smaller components

Kernel/FileSystem/FATFS/Definitions.h

@@ -0,0 +1,106 @@
+/*
+ * Copyright (c) 2022, Undefine <undefine@undefine.pl>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/EnumBits.h>
+#include <AK/Types.h>
+
+namespace Kernel {
+
+struct [[gnu::packed]] FAT32BootRecord {
+    u8 boot_jump[3];
+    char oem_identifier[8];
+    u16 bytes_per_sector;
+    u8 sectors_per_cluster;
+    u16 reserved_sector_count;
+    u8 fat_count;
+    u16 root_directory_entry_count;
+    u16 unused1;
+    u8 media_descriptor_type;
+    u16 unused2;
+    u16 sectors_per_track;
+    u16 head_count;
+    u32 hidden_sector_count;
+    u32 sector_count;
+    u32 sectors_per_fat;
+    u16 flags;
+    u16 fat_version;
+    u32 root_directory_cluster;
+    u16 fs_info_sector;
+    u16 backup_boot_sector;
+    u8 unused3[12];
+    u8 drive_number;
+    u8 unused4;
+    u8 signature;
+    u32 volume_id;
+    char volume_label_string[11];
+    char system_identifier_string[8];
+};
+static_assert(sizeof(FAT32BootRecord) == 90);
+
+enum class FATAttributes : u8 {
+    ReadOnly = 0x01,
+    Hidden = 0x02,
+    System = 0x04,
+    VolumeID = 0x08,
+    Directory = 0x10,
+    Archive = 0x20,
+    LongFileName = 0x0F
+};
+
+AK_ENUM_BITWISE_OPERATORS(FATAttributes);
+
+union FATPackedTime {
+    u16 value;
+    struct {
+        u16 second : 5;
+        u16 minute : 6;
+        u16 hour : 5;
+    };
+};
+static_assert(sizeof(FATPackedTime) == 2);
+
+union FATPackedDate {
+    u16 value;
+    struct {
+        u16 day : 5;
+        u16 month : 4;
+        u16 year : 7;
+    };
+};
+static_assert(sizeof(FATPackedDate) == 2);
+
+struct [[gnu::packed]] FATEntry {
+    char filename[8];
+    char extension[3];
+    FATAttributes attributes;
+    u8 unused1;
+    u8 creation_time_seconds;
+    FATPackedTime creation_time;
+    FATPackedDate creation_date;
+    FATPackedDate last_accessed_date;
+    u16 first_cluster_high;
+    FATPackedTime modification_time;
+    FATPackedDate modification_date;
+    u16 first_cluster_low;
+    u32 file_size;
+};
+static_assert(sizeof(FATEntry) == 32);
+
+struct [[gnu::packed]] FATLongFileNameEntry {
+    u8 entry_index;
+    u16 characters1[5];
+    FATAttributes attributes;
+    u8 entry_type;
+    u8 checksum;
+    u16 characters2[6];
+    u16 zero;
+    u16 characters3[2];
+};
+static_assert(sizeof(FATLongFileNameEntry) == 32);
+
+}