aplfw/driver/volume/fat/fatvol_write.c

   1 /**
   2  *  Hyper Operating System  Application Framework
   3  *
   4  * @file  fatvol.c
   5  * @brief %jp{FATボリューム用デバイスドライバ}
   6  *
   7  * Copyright (C) 2006-2007 by Project HOS
   8  * http://sourceforge.jp/projects/hos/
   9  */
  10
  11
  12 #include <string.h>
  13 #include "fatvol_local.h"
  14
  15
  16 /** %jp{書き込み} */
  17 FILE_SIZE FatVol_Write(C_DRVOBJ *pDrvObj, C_FILEOBJ *pFileObj, const void *pData, FILE_SIZE Size)
  18 {
  19         C_FATVOL                        *self;
  20         C_FATFILE                       *pFile;
  21
  22         FILE_SIZE                       ReqSize;
  23         const unsigned char     *pubData;
  24         FATVOL_UINT                     uiNextCluster;
  25         FATVOL_UINT                     uiCluster;
  26         FATVOL_UINT                     i;
  27         int                 iResizeFlag = 0;
  28
  29
  30         /* upper cast */
  31         self  = (C_FATVOL *)pDrvObj;
  32         pFile = (C_FATFILE *)pFileObj;
  33
  34         /* キャスト */
  35         pubData = (const unsigned char *)pData;
  36
  37         /* サイズ0なら即時成功 */
  38         if ( Size <= 0 )
  39         {
  40                 return 0;
  41         }
  42
  43         /* クリティカルセクションに入る */
  44         SysMtx_Lock(self->hMtx);
  45
  46         /* モードチェック */
  47         if ( !(pFile->iMode & FILE_OPEN_WRITE) || (pFile->iMode & FILE_OPEN_DIR) )
  48         {
  49                 SysMtx_Unlock(self->hMtx);
  50                 return 0;
  51         }
  52
  53         /* 書き込み要求量保存 */
  54         ReqSize = Size;
  55
  56         /* ファイルポインタ位置のクラスタを検索 */
  57         uiCluster = pFile->uiStartCluster;
  58         for ( i = 0; pFile->FilePos >= (i + 1) * self->BytesPerCluster; i++ )
  59         {
  60                 /* 次のクラスタを探す */
  61                 uiNextCluster = FatVol_GetNextCluster(self, uiCluster);
  62                 if ( uiNextCluster == FATVOL_CLUSTER_ENDMARKER )
  63                 {
  64                         /* 次クラスタが無ければ作る */
  65                         uiNextCluster = FatVol_GetNewCluster(self);
  66                         if ( uiNextCluster == FATVOL_CLUSTER_ENDMARKER )
  67                         {
  68                                 return 0;       /* ディスクフル */
  69                         }
  70                         FatVol_SetNextCluster(self, uiCluster, uiNextCluster);
  71                 }
  72                 uiCluster = uiNextCluster;
  73         }
  74
  75
  76         /* 書き出し */
  77         while ( Size > 0 )
  78         {
  79                 FILE_POS                        WriteStart;
  80                 FILE_SIZE                       WriteSize;
  81                 T_FATVOL_CLUSTERBUF     *pClusterBuf;
  82
  83                 /* 転送位置計算 */
  84                 WriteStart = (pFile->FilePos & (self->BytesPerCluster - 1));
  85                 WriteSize  = self->BytesPerCluster - WriteStart;
  86                 if ( WriteSize > Size )
  87                 {
  88                         WriteSize = Size;
  89                 }
  90
  91                 /* バッファ取得 */
  92                 if ( WriteStart == 0 && pFile->FilePos == pFile->FileSize )
  93                 {
  94                         pClusterBuf = FatVol_GetClusterBuf(self, uiCluster, 1);         /* 完全新規の場合 */
  95                 }
  96                 else
  97                 {
  98                         pClusterBuf = FatVol_GetClusterBuf(self, uiCluster, 0);         /* 部分更新の場合 */
  99                 }
 100                 if ( pClusterBuf == NULL )
 101                 {
 102                         break;
 103                 }
 104
 105                 /* 転送 */
 106                 memcpy(&pClusterBuf->pubBuf[WriteStart], pubData, WriteSize);
 107
 108                 /* バッファ開放 */
 109                 FatVol_RelClusterBuf(self, pClusterBuf, 1);
 110
 111
 112                 /* サイズ更新 */
 113                 pFile->FilePos += WriteSize;
 114                 pubData        += WriteSize;
 115                 Size           -= WriteSize;
 116
 117                 /* ファイルサイズ更新 */
 118                 if ( pFile->FileSize < pFile->FilePos )
 119                 {
 120                         pFile->FileSize = pFile->FilePos;
 121                         iResizeFlag     = 1;
 122                 }
 123
 124                 /* 完了チェック */
 125                 if ( Size <= 0 )
 126                 {
 127                         break;
 128                 }
 129
 130                 /* 次のクラスタを探す */
 131                 uiNextCluster = FatVol_GetNextCluster(self, uiCluster);
 132                 if ( uiNextCluster == FATVOL_CLUSTER_ENDMARKER )
 133                 {
 134                         /* 次クラスタが無ければ作る */
 135                         uiNextCluster = FatVol_GetNewCluster(self);
 136                         if ( uiNextCluster == FATVOL_CLUSTER_ENDMARKER )
 137                         {
 138                                 break;  /* ディスクフル */
 139                         }
 140                         FatVol_SetNextCluster(self, uiCluster, uiNextCluster);
 141                 }
 142                 uiCluster = uiNextCluster;
 143
 144                 /* 一旦ロックを放す */
 145                 SysMtx_Unlock(self->hMtx);
 146                 SysMtx_Lock(self->hMtx);
 147         }
 148
 149         /* ディレクトリテーブルのサイズ更新 */
 150         if ( iResizeFlag &&     !(pFile->iMode & FILE_OPEN_DIR) )
 151         {
 152                 FatVol_SyncFileSize(self, pFile);
 153         }
 154
 155         /* クリティカルセクションを出る */
 156         SysMtx_Unlock(self->hMtx);
 157
 158         return ReqSize - Size;
 159 }
 160
 161
 162 /* end of file */