#include "../kernel/elf.hpp"
#include "../kernel/frame_buffer_config.hpp"
#include "../kernel/memory_map.hpp"

$ unlink MikanLoaderPkg # 前に残っていたシンボリックリンクを削除
$ ln -s /mnt/30DayOS/workspace/ch17/MikanLoaderPkg/ ./
$ source edksetup.sh
$ build

    EFI_BLOCK_IO_PROTOCOL* block_io;
    status = OpenBlockIoProtocolForLoadedImage(image_handle, &block_io);
    if (EFI_ERROR(status)) {
      Print(L"failed to open Block I/O Protocol: %r\n", status);
      Halt();
    }

    EFI_BLOCK_IO_MEDIA* media = block_io->Media;
    UINTN volume_bytes = (UINTN)media->BlockSize * (media->LastBlock + 1);
    if (volume_bytes > 16 * 1024 * 1024) {
      volume_bytes = 16 * 1024 * 1024;
    }

    Print(L"Reading %lu bytes (Present %d, BlockSize %u, LastBlock %u)\n",
          volume_bytes, media->MediaPresent, media->BlockSize,
          media->LastBlock);

    status = ReadBlocks(block_io, media->MediaId, volume_bytes, &volume_image);
    if (EFI_ERROR(status)) {
      Print(L"failed to read blocks: %r\n", status);
      Halt();
    }

  // dump_volume
  uint8_t* p = reinterpret_cast<uint8_t*>(volume_image);
  printk("Volume Image:\n");
  for (int i = 0; i < 16; ++i) {
    printk("%04x:", i * 16);
    for (int j = 0; j < 8; ++j) {
      printk(" %02x", *p);
      ++p;
    }
    printk(" ");
    for (int j = 0; j < 8; ++j) {
      printk(" %02x", *p);
      ++p;
    }
    printk("\n");
  }
  //--------------------------------------------

  } else if (strcmp(command, "ls") == 0) {
    auto root_dir_entries = fat::GetSectorByCluster<fat::DirectoryEntry>(
        fat::boot_volume_image->root_cluster);
    auto entries_per_cluster = fat::boot_volume_image->bytes_per_sector /
                               sizeof(fat::DirectoryEntry) *
                               fat::boot_volume_image->sectors_per_cluster;
    char base[9], ext[4];
    char s[64];
    for (int i = 0; i < entries_per_cluster; ++i) {
      ReadName(root_dir_entries[i], base, ext);
      if (base[0] == 0x00) {
        break;
      } else if (static_cast<uint8_t>(base[0]) == 0xe5) {
        continue;
      } else if (root_dir_entries[i].attr == fat::Attribute::kLongName) {
        continue;
      }

      if (ext[0]) {
        sprintf(s, "%s.%s\n", base, ext);
      } else {
        sprintf(s, "%s\n", base);
      }
      Print(s);
    }
  }

void ReadName(const DirectoryEntry& entry, char* base, char* ext) {
  memcpy(base, &entry.name[0], 8);
  base[8] = 0;
  for (int i = 7; i >= 0 && base[i] == 0x20; --i) {
    base[i] = 0;
  }

  memcpy(ext, &entry.name[8], 3);
  ext[3] = 0;
  for (int i = 2; i >= 0 && ext[i] == 0x20; --i) {
    ext[i] = 0;
  }
}

ファイル名         DIR_Name          解説
"FILENAME.TXT"    "FILENAMETXT"     ドットは除去される
"DOG.AVI"         "DOG     AVI"     8+3バイトに満たないときはスペースでパディング
"File.Txt"        "FILE    TXT"     ASCII小文字は全て大文字に置き換えられる
"file.TXT"        "FILE    TXT"     ↑に同じ
"蜃気楼.JPG"      "・気楼  JPG"      "蜃"の第一バイトが0xE5なので0x05に置き換え
"NO_EXT"          "NO_EXT     "     拡張子無し
"NO_EXT."         "NO_EXT     "     ↑に同じ
".cnf"                              ※本体無しは不可
"new file.txt"                      ※スペースは使用不可
"file[1].c++"                       ※[]や+はダメ文字
"longext.jpeg"                      ※8+3形式に入らないのはダメ
"arch.tar.gz"                       ※8+3形式に入らないのはダメ

"DOG.AVI"         "DOG     AVI"     8+3バイトに満たないときはスペースでパディング
"File.Txt"        "FILE    TXT"     ASCII小文字は全て大文字に置き換えられる
"file.TXT"        "FILE    TXT"     ↑に同じ

uintptr_t GetClusterAddr(unsigned long cluster) {
  unsigned long sector_num =
    boot_volume_image->reserved_sector_count +
    boot_volume_image->num_fats * boot_volume_image->fat_size_32 +
    (cluster - 2) * boot_volume_image->sectors_per_cluster;
  uintptr_t offset = sector_num * boot_volume_image->bytes_per_sector;
  return reinterpret_cast<uintptr_t>(boot_volume_image) + offset;
}