ff.c

S64和VS1003的MP3播放实现的源代码/

/*--------------------------------------------------------------------------/
/  FatFs - FAT file system module  R0.04                     (C)ChaN, 2007
/---------------------------------------------------------------------------/
/ 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. 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.
/                       Added f_mkfs().
/---------------------------------------------------------------------------*/

#include <string.h>
#include "ff.h"			/* FatFs declarations */
#include "diskio.h"		/* Include file for user provided disk functions */

#define ld2pd(drv) (drv)	/* Logical drive# to Physical drive# conversion */


/*--------------------------------------------------------------------------

   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 == 0
		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;
					if (disk_write(fs->drive, fs->win, wsect, 1) != RES_OK)
						break;
				}
			}
		}
#endif
		if (sector) {
			if (disk_read(fs->drive, fs->win, sector, 1) != RES_OK)
				return FALSE;
			fs->winsect = sector;
		}
	}
	return TRUE;
}




/*-----------------------------------------------------------------------*/
/* 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 / 512)) break;
			wc = fs->win[bc % 512]; bc++;
			if (!move_window(fs, fatsect + bc / 512)) break;
			wc |= (WORD)fs->win[bc % 512] << 8;
			return (clust & 1) ? (wc >> 4) : (wc & 0xFFF);

		case FS_FAT16 :
			if (!move_window(fs, fatsect + clust / 256)) break;
			return LD_WORD(&fs->win[((WORD)clust * 2) % 512]);

		case FS_FAT32 :
			if (!move_window(fs, fatsect + clust / 128)) break;
			return LD_DWORD(&fs->win[((WORD)clust * 4) % 512]) & 0x0FFFFFFF;
		}
	}
	return 1;	/* There is no cluster information, or an error occured */
}




/*-----------------------------------------------------------------------*/
/* Change a Cluster Status                                               */
/*-----------------------------------------------------------------------*/

#if _FS_READONLY == 0
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 / 512)) return FALSE;
		p = &fs->win[bc % 512];
		*p = (clust & 1) ? ((*p & 0x0F) | ((BYTE)val << 4)) : (BYTE)val;
		bc++;
		fs->winflag = 1; 
		if (!move_window(fs, fatsect + bc / 512)) return FALSE;
		p = &fs->win[bc % 512];
		*p = (clust & 1) ? (BYTE)(val >> 4) : ((*p & 0xF0) | ((BYTE)(val >> 8) & 0x0F));
		break;

	case FS_FAT16 :
		if (!move_window(fs, fatsect + clust / 256)) return FALSE;
		ST_WORD(&fs->win[((WORD)clust * 2) % 512], (WORD)val);
		break;

	case FS_FAT32 :
		if (!move_window(fs, fatsect + clust / 128)) return FALSE;
		ST_DWORD(&fs->win[((WORD)clust * 4) % 512], val);
		break;

	default :
		return FALSE;
	}
	fs->winflag = 1;
	return TRUE;
}
#endif /* _FS_READONLY */




/*-----------------------------------------------------------------------*/
/* Remove a Cluster Chain                                                */
/*-----------------------------------------------------------------------*/

#if _FS_READONLY == 0
static
BOOL remove_chain (		/* TRUE: successful, FALSE: failed */
	FATFS *fs,			/* File system object */
	DWORD clust			/* Cluster# to remove chain from */
)
{
	DWORD nxt;


	if (clust) {
		while ((nxt = get_cluster(fs, clust)) >= 2) {
			if (!put_cluster(fs, clust, 0)) return FALSE;
			clust = nxt;
		}
	}
	return TRUE;
}
#endif




/*-----------------------------------------------------------------------*/
/* Stretch or Create a Cluster Chain                                     */
/*-----------------------------------------------------------------------*/

#if _FS_READONLY == 0
static
DWORD create_chain (	/* !=0: new cluster number, 0: failed */
	FATFS *fs,			/* File system object */
	DWORD clust			/* Cluster# to stretch, 0 means create new */
)
{
	DWORD cstat, ncl, scl, mcl;


	mcl = fs->max_clust;
	if (clust == 0) {		/* Create new chain */
		scl = fs->last_clust;			/* Get last allocated cluster */
		if (scl < 2 || scl >= mcl) scl = 1;
	}
	else {					/* Stretch existing chain */
		cstat = get_cluster(fs, clust);		/* Check the cluster status */
		if (cstat < 2) return 0;			/* It is an invalid cluster */
		if (cstat < mcl) return cstat;		/* It is already followed by next cluster */
		scl = clust;
	}
	ncl = scl;				/* Start cluster */
	do {
		ncl++;							/* Next cluster */
		if (ncl >= mcl) {				/* Wrap around */
			ncl = 2;
			if (scl == 1) return 0;		/* No free custer was found */
		}
		if (ncl == scl) return 0;		/* No free custer was found */
		cstat = get_cluster(fs, ncl);	/* Get the cluster status */
		if (cstat == 1) return 0;		/* Any error occured */
	} while (cstat);					/* Repeat until find a free cluster */

	if (!put_cluster(fs, ncl, 0x0FFFFFFF)) return 0;		/* Mark the new cluster "in use" */
	if (clust && !put_cluster(fs, clust, ncl)) return 0;	/* Link it to previous one if needed */
	fs->last_clust = ncl;

	return ncl;		/* Return new cluster number */
}
#endif /* _FS_READONLY */




/*-----------------------------------------------------------------------*/
/* Get Sector# from Cluster#                                             */
/*-----------------------------------------------------------------------*/

static
DWORD clust2sect (	/* !=0: sector number, 0: failed - invalid cluster# */
	FATFS *fs,		/* File system object */
	DWORD clust		/* Cluster# to be converted */
)
{
	clust -= 2;
	if (clust >= fs->max_clust) return 0;		/* Invalid cluster# */
	return clust * fs->sects_clust + fs->database;
}




/*-----------------------------------------------------------------------*/
/* Move Directory Pointer to Next                                        */
/*-----------------------------------------------------------------------*/

static
BOOL next_dir_entry (	/* TRUE: successful, FALSE: could not move next */
	DIR *dirobj			/* Pointer to directory object */
)
{
	DWORD clust;
	WORD idx;
	FATFS *fs = dirobj->fs;


	idx = dirobj->index + 1;
	if ((idx & 15) == 0) {		/* Table sector changed? */
		dirobj->sect++;			/* Next sector */
		if (!dirobj->clust) {		/* In static table */
			if (idx >= fs->n_rootdir) return FALSE;	/* Reached to end of table */
		} else {				/* In dynamic table */
			if (((idx / 16) & (fs->sects_clust - 1)) == 0) {	/* Cluster changed? */
				clust = get_cluster(fs, dirobj->clust);		/* Get next cluster */
				if (clust >= fs->max_clust || clust < 2)	/* Reached to end of table */
					return FALSE;
				dirobj->clust = clust;				/* Initialize for new cluster */
				dirobj->sect = clust2sect(fs, clust);
			}
		}
	}
	dirobj->index = idx;	/* Lower 4 bit of dirobj->index indicates offset in dirobj->sect */
	return TRUE;
}




/*-----------------------------------------------------------------------*/
/* Get File Status from Directory Entry                                  */
/*-----------------------------------------------------------------------*/

#if _FS_MINIMIZE <= 1
static
void get_fileinfo (		/* No return code */
	FILINFO *finfo, 	/* Ptr to store the file information */
	const BYTE *dir		/* Ptr to the directory entry */
)
{
	BYTE n, c, a;
	char *p;


	p = &finfo->fname[0];
	a = *(dir+12);	/* NT flag */
	for (n = 0; n < 8; n++) {	/* Convert file name (body) */
		c = *(dir+n);
		if (c == ' ') break;
		if (c == 0x05) c = 0xE5;
		if (a & 0x08 && c >= 'A' && c <= 'Z') c += 0x20;
		*p++ = c;
	}
	if (*(dir+8) != ' ') {		/* Convert file name (extension) */
		*p++ = '.';
		for (n = 8; n < 11; n++) {
			c = *(dir+n);
			if (c == ' ') break;
			if (a & 0x10 && c >= 'A' && c <= 'Z') c += 0x20;
			*p++ = c;
		}
	}
	*p = '\0';

	finfo->fattrib = *(dir+11);			/* Attribute */
	finfo->fsize = LD_DWORD(dir+28);	/* Size */
	finfo->fdate = LD_WORD(dir+24);		/* Date */
	finfo->ftime = LD_WORD(dir+22);		/* Time */
}
#endif /* _FS_MINIMIZE <= 1 */




/*-----------------------------------------------------------------------*/
/* Pick a Paragraph and Create the Name in Format of Directory Entry     */
/*-----------------------------------------------------------------------*/

static
char make_dirfile (			/* 1: error - detected an invalid format, '\0'|'/': next character */
	const char **path,		/* Pointer to the file path pointer */
	char *dirname			/* Pointer to directory name buffer {Name(8), Ext(3), NT flag(1)} */
)
{
	BYTE n, t, c, a, b;


	memset(dirname, ' ', 8+3);	/* Fill buffer with spaces */
	a = 0; b = 0x18;	/* NT flag */
	n = 0; t = 8;
	for (;;) {
		c = *(*path)++;
		if (c == '\0' || c == '/') {		/* Reached to end of str or directory separator */
			if (n == 0) break;
			dirname[11] = a & b; return c;
		}
		if (c <= ' ') break;		/* Reject invisible chars */
		if (c == '.') {
			if(!(a & 1) && n >= 1 && n <= 8) {	/* Enter extension part */
				n = 8; t = 11; continue;
			}
			break;
		}
#ifdef _USE_SJIS
		if ((c >= 0x81 && c <= 0x9F) ||			/* Accept S-JIS code */
		    (c >= 0xE0 && c <= 0xFC)) {
			if (n == 0 && c == 0xE5)			/* Change heading \xE5 to \x05 */
				c = 0x05;
			a ^= 1; goto md_l2;
		}
		if (c >= 0x7F && c <= 0x80) break;		/* Reject \x7F \x80 */
#else
		if (c >= 0x7F) goto md_l1;				/* Accept \x7F-0xFF */
#endif
		if (c == '"') break;					/* Reject " */
		if (c <= ')') goto md_l1;				/* Accept ! # $ % & ' ( ) */
		if (c <= ',') break;					/* Reject * + , */
		if (c <= '9') goto md_l1;				/* Accept - 0-9 */
		if (c <= '?') break;					/* Reject : ; < = > ? */
		if (!(a & 1)) {	/* These checks are not applied to S-JIS 2nd byte */
			if (c == '|') break;				/* Reject | */
			if (c >= '[' && c <= ']') break;/* Reject [ \ ] */
			if (c >= 'A' && c <= 'Z')
				(t == 8) ? (b &= ~0x08) : (b &= ~0x10);
			if (c >= 'a' && c <= 'z') {			/* Convert to upper case */
				c -= 0x20;
				(t == 8) ? (a |= 0x08) : (a |= 0x10);
			}
		}
	md_l1: