aplfw/volume/fat/fatvol_create.c

   1
   2 #include <string.h>
   3 #include "fatvol_local.h"
   4
   5
   6 int FatVol_Create(C_FATVOL *self, HANDLE hBlockFile)
   7 {
   8         unsigned char ubBuf[512];
   9         int           i;
  10
  11         /* ドライブの設定 */
  12         self->hBlockFile = hBlockFile;
  13         self->uiOffset   = 0x33*512;
  14
  15         /* サイズ取得 */
  16         self->uiDriveSize = File_Seek(self->hBlockFile, FILE_SEEK_END, 0);
  17         self->iFatType    = FATVOL_TYPE_UNKNOWN;
  18
  19         /* BIOS Parameter Block */
  20         File_Seek(self->hBlockFile, self->uiOffset, FILE_SEEK_SET);
  21         File_Read(self->hBlockFile, ubBuf, 512);
  22
  23         /* FAT12/16/32判定 */
  24         if ( ubBuf[0x36] == 'F' && ubBuf[0x37] == 'A' && ubBuf[0x38] == 'T' && ubBuf[0x39] == '1' )
  25         {
  26                 if ( ubBuf[0x3a] == '2' )
  27                 {
  28                         self->iFatType = FATVOL_TYPE_FAT12;
  29                 }
  30                 else if ( ubBuf[0x3a] == '6' )
  31                 {
  32                         self->iFatType = FATVOL_TYPE_FAT16;
  33                 }
  34         }
  35         else if ( ubBuf[0x52] == 'F' && ubBuf[0x53] == 'A' && ubBuf[0x54] == 'T' && ubBuf[0x55] == '3' && ubBuf[0x56] == '2')
  36         {
  37                 self->iFatType = FATVOL_TYPE_FAT32;
  38         }
  39
  40         /* フォーマット別情報解析 */
  41         switch ( self->iFatType )
  42         {
  43         case FATVOL_TYPE_FAT12:
  44         case FATVOL_TYPE_FAT16:
  45                 self->uiBytesPerSector    = ubBuf[0x0b] + ubBuf[0x0c] * 256;            /**< セクタサイズ */
  46                 self->uiSectorsPerCluster = ubBuf[0x0d];                                                        /**< 1クラスタのセクタ数 */
  47                 self->uiRootDirEntryNum   = ubBuf[0x11] + ubBuf[0x12] * 256;            /**< ルートディレクトリ最大エントリ数 */
  48                 self->uiFatStartSector    = ubBuf[0x0e] + ubBuf[0x0f] * 256;            /**< FATの開始セクタ番号 */
  49                 self->uiSectorPerFat      = ubBuf[0x16] + ubBuf[0x17] * 256;            /**< FATあたりのセクタ数 */
  50                 self->uiFatNum            = ubBuf[0x10];                                                        /**< FAT個数 */
  51                 self->uiRootDirSector     = self->uiFatStartSector + (self->uiSectorPerFat * self->uiFatNum);
  52                                                                                                                                                         /**< ルートディレクトリ開始位置 */
  53                 self->uiCluster0Sector    = self->uiRootDirSector
  54                                                                                 + (((self->uiRootDirEntryNum * 32) + self->uiBytesPerSector - 1) / self->uiBytesPerSector)
  55                                                                                 - (2 * self->uiSectorsPerCluster);      /**< クラスタ0の開始セクタ */
  56
  57                 /* FATバッファ準備 */
  58                 self->pubFatBuf   = (unsigned char *)SysMem_Alloc(self->uiSectorPerFat * self->uiBytesPerSector);
  59                 self->pubFatDirty = (unsigned char *)SysMem_Alloc(self->uiSectorPerFat);
  60
  61                 /* FATバッファ準備 */
  62                 File_Seek(self->hBlockFile, self->uiFatStartSector * self->uiBytesPerSector, FILE_SEEK_SET);
  63                 File_Read(self->hBlockFile, self->pubFatBuf, self->uiSectorPerFat * self->uiBytesPerSector);
  64                 memset(self->pubFatDirty, 0, self->uiSectorPerFat);
  65
  66                 break;
  67
  68         case FATVOL_TYPE_FAT32:
  69                 break;
  70
  71         default:
  72                 return FATVOL_ERR_NG;
  73         }
  74
  75         /* 最大クラスタ番号算出 */
  76         switch ( self->iFatType )
  77         {
  78         case FATVOL_TYPE_FAT12:
  79                 self->uiMaxClusterNum = (self->uiSectorPerFat * self->uiBytesPerSector) / 3 * 2;
  80                 if ( self->uiMaxClusterNum >= 0x0ff7 )
  81                 {
  82                         self->uiMaxClusterNum = 0x0ff6;
  83                 }
  84                 break;
  85
  86         case FATVOL_TYPE_FAT16:
  87                 self->uiMaxClusterNum = (self->uiSectorPerFat * self->uiBytesPerSector) / 2;
  88                 if ( self->uiMaxClusterNum >= 0xfff7 )
  89                 {
  90                         self->uiMaxClusterNum = 0xfff6;
  91                 }
  92                 break;
  93
  94         case FATVOL_TYPE_FAT32:
  95                 self->uiMaxClusterNum = (self->uiSectorPerFat * self->uiBytesPerSector) / 4;
  96                 break;
  97         }
  98
  99         /* クラスタバッファ取得 */
 100         self->iClusterBufIndex = 0;
 101         self->iClusterBufNum   = 32;
 102         self->pClusterBuf = (T_FATVOL_CLUSTERBUF *)SysMem_Alloc(sizeof(T_FATVOL_CLUSTERBUF) * self->iClusterBufNum);
 103         for ( i = 0; i < self->iClusterBufNum; i++ )
 104         {
 105                 self->pClusterBuf[i].uiClusterNum = FATVOL_CLUSTER_ENDMARKER;
 106                 self->pClusterBuf[i].iDirty       = 0;
 107                 self->pClusterBuf[i].pubBuf       = SysMem_Alloc(self->uiSectorsPerCluster * self->uiBytesPerSector);
 108         }
 109
 110         return FATVOL_ERR_OK;
 111 }
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