FatFs在VC6上的移植实现

/*--------------------------------------------------------------------------/ / FatFs - FAT file system module R0.04b (C)ChaN, 2007 /---------------------------------------------------------------------------/ / The FatFs module is an experimenal project to implement FAT file system to / cheap microcontrollers. This is a free software and is opened for education, / research and development under license policy of following trems. / / Copyright (C) 2007, ChaN, all right reserved. / / * The FatFs module is a free software and there is no warranty. / * You can use, modify and/or redistribute it for personal, non-profit or / profit use without any restriction under your responsibility. / * Redistributions of source code must retain the above copyright notice. / /---------------------------------------------------------------------------/ / Feb 26, 2006 R0.00 Prototype. / Apr 29, 2006 R0.01 First stable version. / Jun 01, 2006 R0.02 Added FAT12 support. / Removed unbuffered mode. / Fixed a problem on small (<32M) patition. / Jun 10, 2006 R0.02a Added a configuration option (_FS_MINIMUM). / Sep 22, 2006 R0.03 Added f_rename(). / Changed option _FS_MINIMUM to _FS_MINIMIZE. / Dec 11, 2006 R0.03a Improved cluster scan algolithm to write files fast. / Fixed f_mkdir() creates incorrect directory on FAT32. / Feb 04, 2007 R0.04 Supported multiple drive system. / Changed some interfaces for multiple drive system. / Changed f_mountdrv() to f_mount(). / Added f_mkfs(). / Apr 01, 2007 R0.04a Supported multiple partitions on a plysical drive. / Added a capability of extending file size to f_lseek(). / Added minimization level 3. / Fixed an endian sensitive code in f_mkfs(). / May 05, 2007 R0.04b Added a configuration option _USE_NTFLAG. / Added FSInfo support. / Fixed DBCS name can result FR_INVALID_NAME. / Fixed short seek (<= csize) collapses the file object. /---------------------------------------------------------------------------*/ #include <string.h> #include "ff.h" /* FatFs declarations */ #include "diskio.h" /* Include file for user provided disk functions */ /*-------------------------------------------------------------------------- Module Private Functions ---------------------------------------------------------------------------*/ static FATFS *FatFs[_DRIVES]; /* Pointer to the file system objects (logical drives) */ static WORD fsid; /* File system mount ID */ /*-----------------------------------------------------------------------*/ /* Change window offset */ /*-----------------------------------------------------------------------*/ static BOOL move_window ( /* TRUE: successful, FALSE: failed */ FATFS *fs, /* File system object */ DWORD sector /* Sector number to make apperance in the fs->win[] */ ) /* Move to zero only writes back dirty window */ { DWORD wsect; wsect = fs->winsect; if (wsect != sector) { /* Changed current window */ #if !_FS_READONLY BYTE n; if (fs->winflag) { /* Write back dirty window if needed */ if (disk_write(fs->drive, fs->win, wsect, 1) != RES_OK) return FALSE; fs->winflag = 0; if (wsect < (fs->fatbase + fs->sects_fat)) { /* In FAT area */ for (n = fs->n_fats; n >= 2; n--) { /* Refrect the change to FAT copy */ wsect += fs->sects_fat; disk_write(fs->drive, fs->win, wsect, 1); } } } #endif if (sector) { if (disk_read(fs->drive, fs->win, sector, 1) != RES_OK) return FALSE; fs->winsect = sector; } } return TRUE; } /*-----------------------------------------------------------------------*/ /* Clean-up cached data */ /*-----------------------------------------------------------------------*/ #if !_FS_READONLY static FRESULT sync ( /* FR_OK: successful, FR_RW_ERROR: failed */ FATFS *fs /* File system object */ ) { fs->winflag = 1; if (!move_window(fs, 0)) return FR_RW_ERROR; #if _USE_FSINFO if (fs->fs_type == FS_FAT32 && fs->fsi_flag) { /* Update FSInfo sector if needed */ fs->winsect = 0; memset(fs->win, 0, 512); ST_WORD(&fs->win[BS_55AA], 0xAA55); ST_DWORD(&fs->win[FSI_LeadSig], 0x41615252); ST_DWORD(&fs->win[FSI_StrucSig], 0x61417272); ST_DWORD(&fs->win[FSI_Free_Count], fs->free_clust); ST_DWORD(&fs->win[FSI_Nxt_Free], fs->last_clust); disk_write(0, fs->win, fs->fsi_sector, 1); fs->fsi_flag = 0; } #endif if (disk_ioctl(fs->drive, CTRL_SYNC, NULL) != RES_OK) return FR_RW_ERROR; return FR_OK; } #endif /*-----------------------------------------------------------------------*/ /* Get a cluster status */ /*-----------------------------------------------------------------------*/ static DWORD get_cluster ( /* 0,>=2: successful, 1: failed */ FATFS *fs, /* File system object */ DWORD clust /* Cluster# to get the link information */ ) { WORD wc, bc; DWORD fatsect; if (clust >= 2 && clust < fs->max_clust) { /* Valid cluster# */ fatsect = fs->fatbase; switch (fs->fs_type) { case FS_FAT12 : bc = (WORD)clust * 3 / 2; if (!move_window(fs, fatsect + (bc / S_SIZ))) break; wc = fs->win[bc & (S_SIZ - 1)]; bc++; if (!move_window(fs, fatsect + (bc / S_SIZ))) break; wc |= (WORD)fs->win[bc & (S_SIZ - 1)] << 8; return (clust & 1) ? (wc >> 4) : (wc & 0xFFF); case FS_FAT16 : if (!move_window(fs, fatsect + (clust / (S_SIZ / 2)))) break; return LD_WORD(&fs->win[((WORD)clust * 2) & (S_SIZ - 1)]); case FS_FAT32 : if (!move_window(fs, fatsect + (clust / (S_SIZ / 4)))) break; return LD_DWORD(&fs->win[((WORD)clust * 4) & (S_SIZ - 1)]) & 0x0FFFFFFF; } } return 1; /* There is no cluster information, or an error occured */ } /*-----------------------------------------------------------------------*/ /* Change a cluster status */ /*-----------------------------------------------------------------------*/ #if !_FS_READONLY static BOOL put_cluster ( /* TRUE: successful, FALSE: failed */ FATFS *fs, /* File system object */ DWORD clust, /* Cluster# to change */ DWORD val /* New value to mark the cluster */ ) { WORD bc; BYTE *p; DWORD fatsect; fatsect = fs->fatbase; switch (fs->fs_type) { case FS_FAT12 : bc = (WORD)clust * 3 / 2; if (!move_window(fs, fatsect + (bc / S_SIZ))) return FALSE; p = &fs->win[bc & (S_SIZ - 1)]; *p = (clust & 1) ? ((*p & 0x0F) | ((BYTE)val << 4)) : (BYTE)val; bc++; fs->winflag = 1; if (!move_window(fs, fatsect + (bc / S_SIZ))) return FALSE; p = &fs->win[bc & (S_SIZ - 1)]; *p = (clust & 1) ? (BYTE)(val >> 4) : ((*p & 0xF0) | ((BYTE)(val >> 8) & 0x0F)); break; case FS_FAT16 : if (!move_window(fs, fatsect + (clust / (S_SIZ / 2)))) return FALSE; ST_WORD(&fs->win[((WORD)clust * 2) & (S_SIZ - 1)], (WORD)val); break; case FS_FAT32 : if (!move_window(fs, fatsect + (clust / (S_SIZ / 4)))) return FALSE; ST_DWORD(&fs->win[((WORD)clust * 4) & (S_SIZ - 1)], val); break; default : return FALSE; } fs->winflag = 1; return TRUE; } #endif /* !_FS_READONLY */ /*-----------------------------------------------------------------------*/ /* Remove a cluster chain */ /*-----------------------------------------------------------------------*/ #if !_FS_READONLY static BOOL remove_chain ( /* TRUE: successful, FALSE: failed