savelij13
fca959be37
- Improved write throughput at the fragmented file on the exFAT volume. - Made memory usage for exFAT be able to be reduced as decreasing _MAX_LFN. - Fixed successive f_getfree() can return wrong count on the FAT12/16 volume. (appeared at R0.12) - Fixed configuration option _VOLUMES cannot be set 10. (appeared at R0.10c)
63 lines
3.8 KiB
HTML
63 lines
3.8 KiB
HTML
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<link rel="up" title="FatFs" href="../00index_e.html">
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<title>FatFs - FATFS</title>
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<div class="para">
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<h2>FATFS</h2>
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<p>The <tt>FATFS</tt> structure (file system object) holds dynamic work area of individual logical drives. It is given by application program and registerd/unregisterd to the FatFs module with <tt>f_mount</tt> function. Initialization of the structure is done by volume mount process whenever necessary. Application program must not modify any member in this structure, or the FAT volume can be collapsed.</p>
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<pre>
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<span class="k">typedef</span> <span class="k">struct</span> {
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BYTE fs_type; <span class="c">/* File system type (0, FS_FAT12, FS_FAT16, FS_FAT32 or FS_EXFAT) */</span>
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BYTE drv; <span class="c">/* Physical drive number */</span>
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BYTE n_fats; <span class="c">/* Number of FAT copies (1,2) */</span>
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BYTE wflag; <span class="c">/* win[] flag (b0:win[] is dirty) */</span>
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BYTE fsi_flag; <span class="c">/* FSINFO flags (b7:Disabled, b0:Dirty) */</span>
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WORD id; <span class="c">/* File system mount ID */</span>
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WORD n_rootdir; <span class="c">/* Number of root directory entries (FAT12/16) */</span>
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WORD csize; <span class="c">/* Sectors per cluster */</span>
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<span class="k">#if</span> _MAX_SS != _MIN_SS
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WORD ssize; <span class="c">/* Sector size (512,1024,2048 or 4096) */</span>
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<span class="k">#endif</span>
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<span class="k">#if _FS_EXFAT</span>
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BYTE* dirbuf; <span class="c">/* Directory entry block scratchpad buffer */</span>
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<span class="k">#endif</span>
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<span class="k">#if</span> _FS_REENTRANT
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_SYNC_t sobj; <span class="c">/* Identifier of sync object */</span>
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<span class="k">#endif</span>
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<span class="k">#if</span> !_FS_READONLY
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DWORD last_clust; <span class="c">/* FSINFO: Last allocated cluster (0xFFFFFFFF if invalid) */</span>
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DWORD free_clust; <span class="c">/* FSINFO: Number of free clusters (0xFFFFFFFF if invalid) */</span>
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<span class="k">#endif</span>
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<span class="k">#if</span> _FS_RPATH
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DWORD cdir; <span class="c">/* Cluster number of current directory (0:root) */</span>
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<span class="k">#if _FS_EXFAT</span>
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DWORD cdc_scl; <span class="c">/* Containing directory start cluster (invalid when cdir is 0) */</span>
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DWORD cdc_size; <span class="c">/* b31-b8:Size of containing directory, b7-b0: Chain status */</span>
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DWORD cdc_ofs; <span class="c">/* Offset in the containing directory (invalid when cdir is 0) */</span>
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<span class="k">#endif</span>
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<span class="k">#endif</span>
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DWORD n_fatent; <span class="c">/* Number of FAT entries (Number of clusters + 2) */</span>
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DWORD fsize; <span class="c">/* Sectors per FAT */</span>
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DWORD volbase; <span class="c">/* Volume base LBA */</span>
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DWORD fatbase; <span class="c">/* FAT base LBA */</span>
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DWORD dirbase; <span class="c">/* Root directory base (LBA|Cluster) */</span>
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DWORD database; <span class="c">/* Data base LBA */</span>
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DWORD winsect; <span class="c">/* Sector LBA appearing in the win[] */</span>
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BYTE win[_MAX_SS]; <span class="c">/* Disk access window for directory, FAT (and file data at tiny cfg) */</span>
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} FATFS;
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</pre>
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</div>
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<p class="foot"><a href="../00index_e.html">Return</a></p>
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