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LibrePilot/flight/pios/common/libraries/dosfs/dosfs.c
Richard Flay (Hyper) a2d8544931 OP-931: adds -Wextra compiler option for the flight code, and makes the bazillion code changes required 
to make the flight code compile again. Needs careful review, particularly all the fixes for the
signed vs unsigned comparisons.

+review OPReview-459
2013-05-05 16:32:24 +09:30

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/*
DOSFS Embedded FAT-Compatible Filesystem
(C) 2005 Lewin A.R.W. Edwards (sysadm@zws.com)
You are permitted to modify and/or use this code in your own projects without
payment of royalty, regardless of the license(s) you choose for those projects.
You cannot re-copyright or restrict use of the code as released by Lewin Edwards.
*/
//#include "common.h"
#include <string.h>
#include <stdlib.h>
//#include "fat.h"
#define div(a,b) ldiv(a,b)
#include "dosfs.h"
/*
Get starting sector# of specified partition on drive #unit
NOTE: This code ASSUMES an MBR on the disk.
scratchsector should point to a SECTOR_SIZE scratch area
Returns 0xffffffff for any error.
If pactive is non-NULL, this function also returns the partition active flag.
If pptype is non-NULL, this function also returns the partition type.
If psize is non-NULL, this function also returns the partition size.
*/
uint32_t DFS_GetPtnStart(uint8_t unit, uint8_t *scratchsector, uint8_t pnum, uint8_t *pactive, uint8_t *pptype, uint32_t *psize)
{
uint32_t result=0;
PMBR mbr = (PMBR) scratchsector;
// DOS ptable supports maximum 4 partitions
if (pnum > 3)
return DFS_ERRMISC;
// Read MBR from target media
if (DFS_ReadSector(unit,scratchsector,0,1)) {
return DFS_ERRMISC;
}
// check if jump to boot, VBR
if(mbr->bootcode[0]==0xEB || mbr->bootcode[0]==0xE9){
// MBR is actually VBR
return 0;
}
result = (uint32_t) mbr->ptable[pnum].start_0 |
(((uint32_t) mbr->ptable[pnum].start_1) << 8) |
(((uint32_t) mbr->ptable[pnum].start_2) << 16) |
(((uint32_t) mbr->ptable[pnum].start_3) << 24);
if (pactive)
*pactive = mbr->ptable[pnum].active;
if (pptype)
*pptype = mbr->ptable[pnum].type;
if (psize)
*psize = (uint32_t) mbr->ptable[pnum].size_0 |
(((uint32_t) mbr->ptable[pnum].size_1) << 8) |
(((uint32_t) mbr->ptable[pnum].size_2) << 16) |
(((uint32_t) mbr->ptable[pnum].size_3) << 24);
return result;
}
/*
Retrieve volume info from BPB and store it in a VOLINFO structure
You must provide the unit and starting sector of the filesystem, and
a pointer to a sector buffer for scratch
Attempts to read BPB and glean information about the FS from that.
Returns 0 OK, nonzero for any error.
*/
uint32_t DFS_GetVolInfo(uint8_t unit, uint8_t *scratchsector, uint32_t startsector, PVOLINFO volinfo)
{
PLBR lbr = (PLBR) scratchsector;
volinfo->unit = unit;
volinfo->startsector = startsector;
#ifdef DEBUG_DOSFS
printf("DFS_GetVolInfo\r\n");
#endif
if(DFS_ReadSector(unit,scratchsector,startsector,1))
return DFS_ERRMISC;
// tag: OEMID, refer dosfs.h
// strncpy(volinfo->oemid, lbr->oemid, 8);
// volinfo->oemid[8] = 0;
volinfo->secperclus = lbr->bpb.secperclus;
volinfo->reservedsecs = (uint16_t) lbr->bpb.reserved_l |
(((uint16_t) lbr->bpb.reserved_h) << 8);
volinfo->numsecs = (uint16_t) lbr->bpb.sectors_s_l |
(((uint16_t) lbr->bpb.sectors_s_h) << 8);
if (!volinfo->numsecs)
volinfo->numsecs = (uint32_t) lbr->bpb.sectors_l_0 |
(((uint32_t) lbr->bpb.sectors_l_1) << 8) |
(((uint32_t) lbr->bpb.sectors_l_2) << 16) |
(((uint32_t) lbr->bpb.sectors_l_3) << 24);
// If secperfat is 0, we must be in a FAT32 volume; get secperfat
// from the FAT32 EBPB. The volume label and system ID string are also
// in different locations for FAT12/16 vs FAT32.
volinfo->secperfat = (uint16_t) lbr->bpb.secperfat_l |
(((uint16_t) lbr->bpb.secperfat_h) << 8);
if (!volinfo->secperfat) {
volinfo->secperfat = (uint32_t) lbr->ebpb.ebpb32.fatsize_0 |
(((uint32_t) lbr->ebpb.ebpb32.fatsize_1) << 8) |
(((uint32_t) lbr->ebpb.ebpb32.fatsize_2) << 16) |
(((uint32_t) lbr->ebpb.ebpb32.fatsize_3) << 24);
memcpy(volinfo->label, lbr->ebpb.ebpb32.label, 11);
volinfo->label[11] = 0;
// tag: OEMID, refer dosfs.h
// memcpy(volinfo->system, lbr->ebpb.ebpb32.system, 8);
// volinfo->system[8] = 0;
}
else {
memcpy(volinfo->label, lbr->ebpb.ebpb.label, 11);
volinfo->label[11] = 0;
// tag: OEMID, refer dosfs.h
// memcpy(volinfo->system, lbr->ebpb.ebpb.system, 8);
// volinfo->system[8] = 0;
}
// note: if rootentries is 0, we must be in a FAT32 volume.
volinfo->rootentries = (uint16_t) lbr->bpb.rootentries_l |
(((uint16_t) lbr->bpb.rootentries_h) << 8);
// after extracting raw info we perform some useful precalculations
volinfo->fat1 = startsector + volinfo->reservedsecs;
// The calculation below is designed to round up the root directory size for FAT12/16
// and to simply ignore the root directory for FAT32, since it's a normal, expandable
// file in that situation.
if (volinfo->rootentries) {
volinfo->rootdir = volinfo->fat1 + (volinfo->secperfat * 2);
volinfo->dataarea = volinfo->rootdir + (((volinfo->rootentries * 32) + (SECTOR_SIZE - 1)) / SECTOR_SIZE);
}
else {
volinfo->dataarea = volinfo->fat1 + (volinfo->secperfat * 2);
volinfo->rootdir = (uint32_t) lbr->ebpb.ebpb32.root_0 |
(((uint32_t) lbr->ebpb.ebpb32.root_1) << 8) |
(((uint32_t) lbr->ebpb.ebpb32.root_2) << 16) |
(((uint32_t) lbr->ebpb.ebpb32.root_3) << 24);
}
// Calculate number of clusters in data area and infer FAT type from this information.
volinfo->numclusters = (volinfo->numsecs - volinfo->dataarea) / volinfo->secperclus;
if (volinfo->numclusters < 4085)
volinfo->filesystem = FAT12;
else if (volinfo->numclusters < 65525)
volinfo->filesystem = FAT16;
else
volinfo->filesystem = FAT32;
return DFS_OK;
}
/*
Fetch FAT entry for specified cluster number
You must provide a scratch buffer for one sector (SECTOR_SIZE) and a populated VOLINFO
Returns a FAT32 BAD_CLUSTER value for any error, otherwise the contents of the desired
FAT entry.
scratchcache should point to a UINT32. This variable caches the physical sector number
last read into the scratch buffer for performance enhancement reasons.
*/
uint32_t DFS_GetFAT(PVOLINFO volinfo, uint8_t *scratch, uint32_t *scratchcache, uint32_t cluster)
{
uint32_t offset=0, sector=0, result=0;
#ifdef DEBUG_DOSFS
printf("DFS_GetFAT\r\n");
#endif
if (volinfo->filesystem == FAT12) {
offset = cluster + (cluster / 2);
}
else if (volinfo->filesystem == FAT16) {
offset = cluster * 2;
}
else if (volinfo->filesystem == FAT32) {
offset = cluster * 4;
}
else
return 0x0ffffff7; // FAT32 bad cluster
// at this point, offset is the BYTE offset of the desired sector from the start
// of the FAT. Calculate the physical sector containing this FAT entry.
sector = ldiv(offset, SECTOR_SIZE).quot + volinfo->fat1;
// If this is not the same sector we last read, then read it into RAM
if (sector != *scratchcache) {
if(DFS_ReadSector(volinfo->unit, scratch, sector, 1)) {
// avoid anyone assuming that this cache value is still valid, which
// might cause disk corruption
*scratchcache = 0;
return 0x0ffffff7; // FAT32 bad cluster
}
*scratchcache = sector;
}
// At this point, we "merely" need to extract the relevant entry.
// This is easy for FAT16 and FAT32, but a royal PITA for FAT12 as a single entry
// may span a sector boundary. The normal way around this is always to read two
// FAT sectors, but that luxury is (by design intent) unavailable to DOSFS.
offset = ldiv(offset, SECTOR_SIZE).rem;
if (volinfo->filesystem == FAT12) {
// Special case for sector boundary - Store last byte of current sector.
// Then read in the next sector and put the first byte of that sector into
// the high byte of result.
if (offset == SECTOR_SIZE - 1) {
result = (uint32_t) scratch[offset];
sector++;
if(DFS_ReadSector(volinfo->unit, scratch, sector, 1)) {
// avoid anyone assuming that this cache value is still valid, which
// might cause disk corruption
*scratchcache = 0;
return 0x0ffffff7; // FAT32 bad cluster
}
*scratchcache = sector;
// Thanks to Claudio Leonel for pointing out this missing line.
result |= ((uint32_t) scratch[0]) << 8;
}
else {
result = (uint32_t) scratch[offset] |
((uint32_t) scratch[offset+1]) << 8;
}
if (cluster & 1)
result = result >> 4;
else
result = result & 0xfff;
}
else if (volinfo->filesystem == FAT16) {
result = (uint32_t) scratch[offset] |
((uint32_t) scratch[offset+1]) << 8;
}
else if (volinfo->filesystem == FAT32) {
result = ((uint32_t) scratch[offset] |
((uint32_t) scratch[offset+1]) << 8 |
((uint32_t) scratch[offset+2]) << 16 |
((uint32_t) scratch[offset+3]) << 24) & 0x0fffffff;
}
else
result = 0x0ffffff7; // FAT32 bad cluster
return result;
}
/*
Set FAT entry for specified cluster number
You must provide a scratch buffer for one sector (SECTOR_SIZE) and a populated VOLINFO
Returns DFS_ERRMISC for any error, otherwise DFS_OK
scratchcache should point to a UINT32. This variable caches the physical sector number
last read into the scratch buffer for performance enhancement reasons.
NOTE: This code is HIGHLY WRITE-INEFFICIENT, particularly for flash media. Considerable
performance gains can be realized by caching the sector. However this is difficult to
achieve on FAT12 without requiring 2 sector buffers of scratch space, and it is a design
requirement of this code to operate on a single 512-byte scratch.
If you are operating DOSFS over flash, you are strongly advised to implement a writeback
cache in your physical I/O driver. This will speed up your code significantly and will
also conserve power and flash write life.
*/
uint32_t DFS_SetFAT(PVOLINFO volinfo, uint8_t *scratch, uint32_t *scratchcache, uint32_t cluster, uint32_t new_contents)
{
uint32_t offset=0, sector=0, result=0;
#ifdef DEBUG_DOSFS
printf("DFS_SetFAT (%lu->%lu)\r\n",cluster,new_contents);
#endif
if (volinfo->filesystem == FAT12) {
offset = cluster + (cluster / 2);
new_contents &=0xfff;
}
else if (volinfo->filesystem == FAT16) {
offset = cluster * 2;
new_contents &=0xffff;
}
else if (volinfo->filesystem == FAT32) {
offset = cluster * 4;
new_contents &=0x0fffffff; // FAT32 is really "FAT28"
}
else
return DFS_ERRMISC;
// at this point, offset is the BYTE offset of the desired sector from the start
// of the FAT. Calculate the physical sector containing this FAT entry.
sector = ldiv(offset, SECTOR_SIZE).quot + volinfo->fat1;
// If this is not the same sector we last read, then read it into RAM
if (sector != *scratchcache) {
if(DFS_ReadSector(volinfo->unit, scratch, sector, 1)) {
// avoid anyone assuming that this cache value is still valid, which
// might cause disk corruption
*scratchcache = 0;
return DFS_ERRMISC;
}
*scratchcache = sector;
}
// At this point, we "merely" need to extract the relevant entry.
// This is easy for FAT16 and FAT32, but a royal PITA for FAT12 as a single entry
// may span a sector boundary. The normal way around this is always to read two
// FAT sectors, but that luxury is (by design intent) unavailable to DOSFS.
offset = ldiv(offset, SECTOR_SIZE).rem;
if (volinfo->filesystem == FAT12) {
// If this is an odd cluster, pre-shift the desired new contents 4 bits to
// make the calculations below simpler
if (cluster & 1)
new_contents = new_contents << 4;
// Special case for sector boundary
if (offset == SECTOR_SIZE - 1) {
// Odd cluster: High 12 bits being set
if (cluster & 1) {
scratch[offset] = (scratch[offset] & 0x0f) | (new_contents & 0xf0);
}
// Even cluster: Low 12 bits being set
else {
scratch[offset] = new_contents & 0xff;
}
result = DFS_WriteSector(volinfo->unit, scratch, *scratchcache, 1);
// mirror the FAT into copy 2
if (DFS_OK == result)
result = DFS_WriteSector(volinfo->unit, scratch, (*scratchcache)+volinfo->secperfat, 1);
// If we wrote that sector OK, then read in the subsequent sector
// and poke the first byte with the remainder of this FAT entry.
if (DFS_OK == result) {
// *scratchcache++;
++*scratchcache; // TK: to avoid warning "value computed is not used"
result = DFS_ReadSector(volinfo->unit, scratch, *scratchcache, 1);
if (DFS_OK == result) {
// Odd cluster: High 12 bits being set
if (cluster & 1) {
scratch[0] = new_contents & 0xff00;
}
// Even cluster: Low 12 bits being set
else {
scratch[0] = (scratch[0] & 0xf0) | (new_contents & 0x0f);
}
result = DFS_WriteSector(volinfo->unit, scratch, *scratchcache, 1);
// mirror the FAT into copy 2
if (DFS_OK == result)
result = DFS_WriteSector(volinfo->unit, scratch, (*scratchcache)+volinfo->secperfat, 1);
}
else {
// avoid anyone assuming that this cache value is still valid, which
// might cause disk corruption
*scratchcache = 0;
}
}
} // if (offset == SECTOR_SIZE - 1)
// Not a sector boundary. But we still have to worry about if it's an odd
// or even cluster number.
else {
// Odd cluster: High 12 bits being set
if (cluster & 1) {
scratch[offset] = (scratch[offset] & 0x0f) | (new_contents & 0xf0);
scratch[offset+1] = new_contents & 0xff00;
}
// Even cluster: Low 12 bits being set
else {
scratch[offset] = new_contents & 0xff;
scratch[offset+1] = (scratch[offset+1] & 0xf0) | (new_contents & 0x0f);
}
result = DFS_WriteSector(volinfo->unit, scratch, *scratchcache, 1);
// mirror the FAT into copy 2
if (DFS_OK == result)
result = DFS_WriteSector(volinfo->unit, scratch, (*scratchcache)+volinfo->secperfat, 1);
}
}
else if (volinfo->filesystem == FAT16) {
scratch[offset] = (new_contents & 0xff);
scratch[offset+1] = (new_contents & 0xff00) >> 8;
result = DFS_WriteSector(volinfo->unit, scratch, *scratchcache, 1);
// mirror the FAT into copy 2 - XXX
if (DFS_OK == result)
result = DFS_WriteSector(volinfo->unit, scratch, (*scratchcache)+volinfo->secperfat, 1);
}
else if (volinfo->filesystem == FAT32) {
scratch[offset] = (new_contents & 0xff);
scratch[offset+1] = (new_contents & 0xff00) >> 8;
scratch[offset+2] = (new_contents & 0xff0000) >> 16;
scratch[offset+3] = (scratch[offset+3] & 0xf0) | ((new_contents & 0x0f000000) >> 24);
// Note well from the above: Per Microsoft's guidelines we preserve the upper
// 4 bits of the FAT32 cluster value. It's unclear what these bits will be used
// for; in every example I've encountered they are always zero.
result = DFS_WriteSector(volinfo->unit, scratch, *scratchcache, 1);
// mirror the FAT into copy 2
if (DFS_OK == result)
result = DFS_WriteSector(volinfo->unit, scratch, (*scratchcache)+volinfo->secperfat, 1);
}
else
result = DFS_ERRMISC;
return result;
}
/*
Convert a filename element from canonical (8.3) to directory entry (11) form
src must point to the first non-separator character.
dest must point to a 12-byte buffer.
*/
uint8_t *DFS_CanonicalToDir(uint8_t *dest, uint8_t *src)
{
uint8_t *destptr = dest;
memset(dest, ' ', 11);
dest[11] = 0;
while (*src && (*src != DIR_SEPARATOR) && (destptr - dest < 11)) {
if (*src >= 'a' && *src <='z') {
*destptr++ = (*src - 'a') + 'A';
src++;
}
else if (*src == '.') {
src++;
destptr = dest + 8;
}
else {
*destptr++ = *src++;
}
}
return dest;
}
/*
Find the first unused FAT entry
You must provide a scratch buffer for one sector (SECTOR_SIZE) and a populated VOLINFO
Returns a FAT32 BAD_CLUSTER value for any error, otherwise the contents of the desired
FAT entry.
Returns FAT32 bad_sector (0x0ffffff7) if there is no free cluster available
*/
uint32_t DFS_GetFreeFAT(PVOLINFO volinfo, uint8_t *scratch)
{
uint32_t i, result = 0xffffffff, scratchcache = 0;
#ifdef DEBUG_DOSFS
printf("DFS_GetFreeFAT\r\n");
#endif
// Search starts at cluster 2, which is the first usable cluster
// NOTE: This search can't terminate at a bad cluster, because there might
// legitimately be bad clusters on the disk.
for (i=2; i < volinfo->numclusters; i++) {
result = DFS_GetFAT(volinfo, scratch, &scratchcache, i);
if (!result) {
return i;
}
}
return 0x0ffffff7; // Can't find a free cluster
}
/*
Open a directory for enumeration by DFS_GetNextDirEnt
You must supply a populated VOLINFO (see DFS_GetVolInfo)
** you must also make sure dirinfo->scratch is valid in the dirinfo you pass it** //reza
The empty string or a string containing only the directory separator are
considered to be the root directory.
Returns 0 OK, nonzero for any error.
*/
uint32_t DFS_OpenDir(PVOLINFO volinfo, uint8_t *dirname, PDIRINFO dirinfo)
{
// Default behavior is a regular search for existing entries
dirinfo->flags = 0;
#ifdef DEBUG_DOSFS
printf("DFS_OpenDir\r\n");
#endif
if (!strlen((char *) dirname) || (strlen((char *) dirname) == 1 && dirname[0] == DIR_SEPARATOR)) {
if (volinfo->filesystem == FAT32) {
dirinfo->currentcluster = volinfo->rootdir;
dirinfo->currentsector = 0;
dirinfo->currententry = 0;
// read first sector of directory
return DFS_ReadSector(volinfo->unit, dirinfo->scratch, volinfo->dataarea + ((volinfo->rootdir - 2) * volinfo->secperclus), 1);
}
else {
dirinfo->currentcluster = 0;
dirinfo->currentsector = 0;
dirinfo->currententry = 0;
// read first sector of directory
return DFS_ReadSector(volinfo->unit, dirinfo->scratch, volinfo->rootdir, 1);
}
}
// This is not the root directory. We need to find the start of this subdirectory.
// We do this by devious means, using our own companion function DFS_GetNext.
else {
uint8_t tmpfn[12];
uint8_t *ptr = dirname;
uint32_t result;
DIRENT de;
if (volinfo->filesystem == FAT32) {
dirinfo->currentcluster = volinfo->rootdir;
dirinfo->currentsector = 0;
dirinfo->currententry = 0;
// read first sector of directory
if (DFS_ReadSector(volinfo->unit, dirinfo->scratch, volinfo->dataarea + ((volinfo->rootdir - 2) * volinfo->secperclus), 1))
return DFS_ERRMISC;
}
else {
dirinfo->currentcluster = 0;
dirinfo->currentsector = 0;
dirinfo->currententry = 0;
// read first sector of directory
if (DFS_ReadSector(volinfo->unit, dirinfo->scratch, volinfo->rootdir, 1))
return DFS_ERRMISC;
}
// skip leading path separators
while (*ptr == DIR_SEPARATOR && *ptr)
ptr++;
// Scan the path from left to right, finding the start cluster of each entry
// Observe that this code is inelegant, but obviates the need for recursion.
while (*ptr) {
DFS_CanonicalToDir(tmpfn, ptr);
de.name[0] = 0;
do {
result = DFS_GetNext(volinfo, dirinfo, &de);
} while (!result && memcmp(de.name, tmpfn, 11));
if (!memcmp(de.name, tmpfn, 11) && ((de.attr & ATTR_DIRECTORY) == ATTR_DIRECTORY)) {
if (volinfo->filesystem == FAT32) {
dirinfo->currentcluster = (uint32_t) de.startclus_l_l |
((uint32_t) de.startclus_l_h) << 8 |
((uint32_t) de.startclus_h_l) << 16 |
((uint32_t) de.startclus_h_h) << 24;
}
else {
dirinfo->currentcluster = (uint32_t) de.startclus_l_l |
((uint32_t) de.startclus_l_h) << 8;
}
dirinfo->currentsector = 0;
dirinfo->currententry = 0;
if (DFS_ReadSector(volinfo->unit, dirinfo->scratch, volinfo->dataarea + ((dirinfo->currentcluster - 2) * volinfo->secperclus), 1))
return DFS_ERRMISC;
}
else if (!memcmp(de.name, tmpfn, 11) && !(de.attr & ATTR_DIRECTORY))
return DFS_NOTFOUND;
// seek to next item in list
while (*ptr != DIR_SEPARATOR && *ptr)
ptr++;
if (*ptr == DIR_SEPARATOR)
ptr++;
}
if (!dirinfo->currentcluster)
return DFS_NOTFOUND;
}
return DFS_OK;
}
/*
Get next entry in opened directory structure. Copies fields into the dirent
structure, updates dirinfo. Note that it is the _caller's_ responsibility to
handle the '.' and '..' entries.
A deleted file will be returned as a NULL entry (first char of filename=0)
by this code. Filenames beginning with 0x05 will be translated to 0xE5
automatically. Long file name entries will be returned as NULL.
returns DFS_EOF if there are no more entries, DFS_OK if this entry is valid,
or DFS_ERRMISC for a media error
*/
uint32_t DFS_GetNext(PVOLINFO volinfo, PDIRINFO dirinfo, PDIRENT dirent)
{
uint32_t tempint; // required by DFS_GetFAT
#ifdef DEBUG_DOSFS
printf("DFS_GetNext\r\n");
#endif
// Do we need to read the next sector of the directory?
if (dirinfo->currententry >= SECTOR_SIZE / sizeof(DIRENT)) {
dirinfo->currententry = 0;
dirinfo->currentsector++;
// Root directory; special case handling
// Note that currentcluster will only ever be zero if both:
// (a) this is the root directory, and
// (b) we are on a FAT12/16 volume, where the root dir can't be expanded
if (dirinfo->currentcluster == 0) {
// Trying to read past end of root directory?
if (dirinfo->currentsector * (SECTOR_SIZE / sizeof(DIRENT)) >= volinfo->rootentries)
return DFS_EOF;
// Otherwise try to read the next sector
if (DFS_ReadSector(volinfo->unit, dirinfo->scratch, volinfo->rootdir + dirinfo->currentsector, 1))
return DFS_ERRMISC;
}
// Normal handling
else {
if (dirinfo->currentsector >= volinfo->secperclus) {
dirinfo->currentsector = 0;
if ((dirinfo->currentcluster >= 0xff7 && volinfo->filesystem == FAT12) ||
(dirinfo->currentcluster >= 0xfff7 && volinfo->filesystem == FAT16) ||
(dirinfo->currentcluster >= 0x0ffffff7 && volinfo->filesystem == FAT32)) {
// We are at the end of the directory chain. If this is a normal
// find operation, we should indicate that there is nothing more
// to see.
if (!(dirinfo->flags & DFS_DI_BLANKENT))
return DFS_EOF;
// On the other hand, if this is a "find free entry" search,
// we need to tell the caller to allocate a new cluster
else
return DFS_ALLOCNEW;
}
dirinfo->currentcluster = DFS_GetFAT(volinfo, dirinfo->scratch, &tempint, dirinfo->currentcluster);
}
if (DFS_ReadSector(volinfo->unit, dirinfo->scratch, volinfo->dataarea + ((dirinfo->currentcluster - 2) * volinfo->secperclus) + dirinfo->currentsector, 1))
return DFS_ERRMISC;
}
}
memcpy(dirent, &(((PDIRENT) dirinfo->scratch)[dirinfo->currententry]), sizeof(DIRENT));
if (dirent->name[0] == 0) { // no more files in this directory
// If this is a "find blank" then we can reuse this name.
#if 0
if (dirinfo->flags & DFS_DI_BLANKENT)
return DFS_OK;
#else
// TK: DFS_GetFreeDirEnt() expects that currententry has been incremented by 1
if (dirinfo->flags & DFS_DI_BLANKENT) {
dirinfo->currententry++;
return DFS_OK;
}
#endif
else
return DFS_EOF;
}
if (dirent->name[0] == 0xe5) // handle deleted file entries
dirent->name[0] = 0;
#if 1
// TK: ensure that DFS_GetFreeDirEnt() doesn't return entries with long name
else if( dirinfo->flags & DFS_DI_BLANKENT )
{} // do nothing..
#endif
else if ((dirent->attr & ATTR_LONG_NAME) == ATTR_LONG_NAME)
dirent->name[0] = 0;
else if (dirent->name[0] == 0x05) // handle kanji filenames beginning with 0xE5
dirent->name[0] = 0xe5;
dirinfo->currententry++;
return DFS_OK;
}
/*
INTERNAL
Find a free directory entry in the directory specified by path
This function MAY cause a disk write if it is necessary to extend the directory
size.
Note - di.scratch must be preinitialized to point to a sector scratch buffer
de is a scratch structure
Returns DFS_ERRMISC if a new entry could not be located or created
de is updated with the same return information you would expect from DFS_GetNext
*/
uint32_t DFS_GetFreeDirEnt(PVOLINFO volinfo, uint8_t *path, PDIRINFO di, PDIRENT de)
{
uint32_t tempclus=0,i=0;
#ifdef DEBUG_DOSFS
printf("DFS_GetFreeDirEnt\r\n");
#endif
if (DFS_OpenDir(volinfo, path, di))
return DFS_NOTFOUND;
// Set "search for empty" flag so DFS_GetNext knows what we're doing
di->flags |= DFS_DI_BLANKENT;
// We seek through the directory looking for an empty entry
// Note we are reusing tempclus as a temporary result holder.
tempclus = 0;
do {
tempclus = DFS_GetNext(volinfo, di, de);
// Empty entry found
if (tempclus == DFS_OK && (!de->name[0])) {
return DFS_OK;
}
// End of root directory reached
else if (tempclus == DFS_EOF)
return DFS_ERRMISC;
else if (tempclus == DFS_ALLOCNEW) {
tempclus = DFS_GetFreeFAT(volinfo, di->scratch);
if (tempclus == 0x0ffffff7)
return DFS_ERRMISC;
// write out zeroed sectors to the new cluster
memset(di->scratch, 0, SECTOR_SIZE);
for (i=0;i<volinfo->secperclus;i++) {
if (DFS_WriteSector(volinfo->unit, di->scratch, volinfo->dataarea + ((tempclus - 2) * volinfo->secperclus) + i, 1))
return DFS_ERRMISC;
}
// Point old end cluster to newly allocated cluster
i = 0;
DFS_SetFAT(volinfo, di->scratch, &i, di->currentcluster, tempclus);
// Update DIRINFO so caller knows where to place the new file
di->currentcluster = tempclus;
di->currentsector = 0;
di->currententry = 1; // since the code coming after this expects to subtract 1
// Mark newly allocated cluster as end of chain
switch(volinfo->filesystem) {
case FAT12: tempclus = 0xff8; break;
case FAT16: tempclus = 0xfff8; break;
case FAT32: tempclus = 0x0ffffff8; break;
default: return DFS_ERRMISC;
}
DFS_SetFAT(volinfo, di->scratch, &i, di->currentcluster, tempclus);
}
} while (!tempclus);
// We shouldn't get here
return DFS_ERRMISC;
}
/*
Open a file for reading or writing. You supply populated VOLINFO, a path to the file,
mode (DFS_READ or DFS_WRITE) and an empty fileinfo structure. You also need to
provide a pointer to a sector-sized scratch buffer.
Returns various DFS_* error states. If the result is DFS_OK, fileinfo can be used
to access the file from this point on.
*/
uint32_t DFS_OpenFile(PVOLINFO volinfo, uint8_t *path, uint8_t mode, uint8_t *scratch, PFILEINFO fileinfo)
{
uint8_t tmppath[MAX_PATH];
uint8_t filename[12];
uint8_t *p;
DIRINFO di;
DIRENT de;
uint32_t temp;
#ifdef DEBUG_DOSFS
printf("DFS_OpenFile\r\n");
#endif
// larwe 2006-09-16 +1 zero out file structure
memset(fileinfo, 0, sizeof(FILEINFO));
// save access mode
fileinfo->mode = mode;
// Get a local copy of the path. If it's longer than MAX_PATH, abort.
strncpy((char *) tmppath, (char *) path, MAX_PATH);
tmppath[MAX_PATH - 1] = 0;
if (strcmp((char *) path,(char *) tmppath)) {
return DFS_PATHLEN;
}
// strip leading path separators
while (tmppath[0] == DIR_SEPARATOR)
strcpy((char *) tmppath, (char *) tmppath + 1);
// Parse filename off the end of the supplied path
p = tmppath;
while (*(p++));
p--;
while (p > tmppath && *p != DIR_SEPARATOR) // larwe 9/16/06 ">=" to ">" bugfix
p--;
if (*p == DIR_SEPARATOR)
p++;
DFS_CanonicalToDir(filename, p);
if (p > tmppath)
p--;
if (*p == DIR_SEPARATOR || p == tmppath) // larwe 9/16/06 +"|| p == tmppath" bugfix
*p = 0;
// At this point, if our path was MYDIR/MYDIR2/FILE.EXT, filename = "FILE EXT" and
// tmppath = "MYDIR/MYDIR2".
di.scratch = scratch;
if (DFS_OpenDir(volinfo, tmppath, &di))
return DFS_NOTFOUND;
while (!DFS_GetNext(volinfo, &di, &de)) {
if (!memcmp(de.name, filename, 11)) {
// You can't use this function call to open a directory.
if (de.attr & ATTR_DIRECTORY)
return DFS_NOTFOUND;
fileinfo->volinfo = volinfo;
fileinfo->pointer = 0;
// The reason we store this extra info about the file is so that we can
// speedily update the file size, modification date, etc. on a file that is
// opened for writing.
if (di.currentcluster == 0)
fileinfo->dirsector = volinfo->rootdir + di.currentsector;
else
fileinfo->dirsector = volinfo->dataarea + ((di.currentcluster - 2) * volinfo->secperclus) + di.currentsector;
fileinfo->diroffset = di.currententry - 1;
if (volinfo->filesystem == FAT32) {
fileinfo->cluster = (uint32_t) de.startclus_l_l |
((uint32_t) de.startclus_l_h) << 8 |
((uint32_t) de.startclus_h_l) << 16 |
((uint32_t) de.startclus_h_h) << 24;
}
else {
fileinfo->cluster = (uint32_t) de.startclus_l_l |
((uint32_t) de.startclus_l_h) << 8;
}
fileinfo->firstcluster = fileinfo->cluster;
fileinfo->filelen = (uint32_t) de.filesize_0 |
((uint32_t) de.filesize_1) << 8 |
((uint32_t) de.filesize_2) << 16 |
((uint32_t) de.filesize_3) << 24;
return DFS_OK;
}
}
// At this point, we KNOW the file does not exist. If the file was opened
// with write access, we can create it.
if (mode & DFS_WRITE) {
uint32_t cluster;
// Locate or create a directory entry for this file
if (DFS_OK != DFS_GetFreeDirEnt(volinfo, tmppath, &di, &de))
return DFS_ERRMISC;
// put sane values in the directory entry
memset(&de, 0, sizeof(de));
memcpy(de.name, filename, 11);
de.crttime_l = 0x20; // 01:01:00am, Jan 1, 2006.
de.crttime_h = 0x08;
de.crtdate_l = 0x11;
de.crtdate_h = 0x34;
de.lstaccdate_l = 0x11;
de.lstaccdate_h = 0x34;
de.wrttime_l = 0x20;
de.wrttime_h = 0x08;
de.wrtdate_l = 0x11;
de.wrtdate_h = 0x34;
// allocate a starting cluster for the directory entry
cluster = DFS_GetFreeFAT(volinfo, scratch);
de.startclus_l_l = cluster & 0xff;
de.startclus_l_h = (cluster & 0xff00) >> 8;
de.startclus_h_l = (cluster & 0xff0000) >> 16;
de.startclus_h_h = (cluster & 0xff000000) >> 24;
// update FILEINFO for our caller's sake
fileinfo->volinfo = volinfo;
fileinfo->pointer = 0;
// The reason we store this extra info about the file is so that we can
// speedily update the file size, modification date, etc. on a file that is
// opened for writing.
if (di.currentcluster == 0)
fileinfo->dirsector = volinfo->rootdir + di.currentsector;
else
fileinfo->dirsector = volinfo->dataarea + ((di.currentcluster - 2) * volinfo->secperclus) + di.currentsector;
fileinfo->diroffset = di.currententry - 1;
fileinfo->cluster = cluster;
fileinfo->firstcluster = cluster;
fileinfo->filelen = 0;
// write the directory entry
// note that we no longer have the sector containing the directory entry,
// tragically, so we have to re-read it
if (DFS_ReadSector(volinfo->unit, scratch, fileinfo->dirsector, 1))
return DFS_ERRMISC;
memcpy(&(((PDIRENT) scratch)[di.currententry-1]), &de, sizeof(DIRENT));
if (DFS_WriteSector(volinfo->unit, scratch, fileinfo->dirsector, 1))
return DFS_ERRMISC;
// Mark newly allocated cluster as end of chain
switch(volinfo->filesystem) {
case FAT12: cluster = 0xff8; break;
case FAT16: cluster = 0xfff8; break;
case FAT32: cluster = 0x0ffffff8; break;
default: return DFS_ERRMISC;
}
temp = 0;
DFS_SetFAT(volinfo, scratch, &temp, fileinfo->cluster, cluster);
return DFS_OK;
}
return DFS_NOTFOUND;
}
/*
Read an open file
You must supply a prepopulated FILEINFO as provided by DFS_OpenFile, and a
pointer to a SECTOR_SIZE scratch buffer.
Note that returning DFS_EOF is not an error condition. This function updates the
successcount field with the number of bytes actually read.
*/
uint32_t DFS_ReadFile(PFILEINFO fileinfo, uint8_t *scratch, uint8_t *buffer, uint32_t *successcount, uint32_t len)
{
uint32_t remain=0;
uint32_t result = DFS_OK;
uint32_t sector=0;
uint32_t bytesread=0;
#ifdef DEBUG_DOSFS
printf("DFS_ReadFile\r\n");
#endif
// Don't try to read past EOF
if (len > fileinfo->filelen - fileinfo->pointer)
len = fileinfo->filelen - fileinfo->pointer;
remain = len;
*successcount = 0;
while (remain && result == DFS_OK) {
// This is a bit complicated. The sector we want to read is addressed at a cluster
// granularity by the fileinfo->cluster member. The file pointer tells us how many
// extra sectors to add to that number.
sector = fileinfo->volinfo->dataarea +
((fileinfo->cluster - 2) * fileinfo->volinfo->secperclus) +
div(div(fileinfo->pointer,fileinfo->volinfo->secperclus * SECTOR_SIZE).rem, SECTOR_SIZE).quot;
// Case 1 - File pointer is not on a sector boundary
if (div(fileinfo->pointer, SECTOR_SIZE).rem) {
uint16_t tempreadsize;
// We always have to go through scratch in this case
result = DFS_ReadSector(fileinfo->volinfo->unit, scratch, sector, 1);
// This is the number of bytes that we actually care about in the sector
// just read.
tempreadsize = SECTOR_SIZE - (div(fileinfo->pointer, SECTOR_SIZE).rem);
// Case 1A - We want the entire remainder of the sector. After this
// point, all passes through the read loop will be aligned on a sector
// boundary, which allows us to go through the optimal path 2A below.
if (remain >= tempreadsize) {
memcpy(buffer, scratch + (SECTOR_SIZE - tempreadsize), tempreadsize);
bytesread = tempreadsize;
buffer += tempreadsize;
fileinfo->pointer += tempreadsize;
remain -= tempreadsize;
}
// Case 1B - This read concludes the file read operation
else {
memcpy(buffer, scratch + (SECTOR_SIZE - tempreadsize), remain);
buffer += remain;
fileinfo->pointer += remain;
bytesread = remain;
remain = 0;
}
}
// Case 2 - File pointer is on sector boundary
else {
// Case 2A - We have at least one more full sector to read and don't have
// to go through the scratch buffer. You could insert optimizations here to
// read multiple sectors at a time, if you were thus inclined (note that
// the maximum multi-read you could perform is a single cluster, so it would
// be advantageous to have code similar to case 1A above that would round the
// pointer to a cluster boundary the first pass through, so all subsequent
// [large] read requests would be able to go a cluster at a time).
if (remain >= SECTOR_SIZE) {
result = DFS_ReadSector(fileinfo->volinfo->unit, buffer, sector, 1);
remain -= SECTOR_SIZE;
buffer += SECTOR_SIZE;
fileinfo->pointer += SECTOR_SIZE;
bytesread = SECTOR_SIZE;
}
// Case 2B - We are only reading a partial sector
else {
result = DFS_ReadSector(fileinfo->volinfo->unit, scratch, sector, 1);
memcpy(buffer, scratch, remain);
buffer += remain;
fileinfo->pointer += remain;
bytesread = remain;
remain = 0;
}
}
*successcount += bytesread;
// check to see if we stepped over a cluster boundary
if (div(fileinfo->pointer - bytesread, fileinfo->volinfo->secperclus * SECTOR_SIZE).quot !=
div(fileinfo->pointer, fileinfo->volinfo->secperclus * SECTOR_SIZE).quot) {
// An act of minor evil - we use bytesread as a scratch integer, knowing that
// its value is not used after updating *successcount above
bytesread = 0;
if (((fileinfo->volinfo->filesystem == FAT12) && (fileinfo->cluster >= 0xff8)) ||
((fileinfo->volinfo->filesystem == FAT16) && (fileinfo->cluster >= 0xfff8)) ||
((fileinfo->volinfo->filesystem == FAT32) && (fileinfo->cluster >= 0x0ffffff8)))
result = DFS_EOF;
else
fileinfo->cluster = DFS_GetFAT(fileinfo->volinfo, scratch, &bytesread, fileinfo->cluster);
}
}
return result;
}
/*
Seek file pointer to a given position
This function does not return status - refer to the fileinfo->pointer value
to see where the pointer wound up.
Requires a SECTOR_SIZE scratch buffer
*/
void DFS_Seek(PFILEINFO fileinfo, uint32_t offset, uint8_t *scratch)
{
uint32_t tempint;
uint16_t endcluster=0; //canny/reza 5/7 fixed
#ifdef DEBUG_DOSFS
printf("DFS_Seek\r\n");
#endif
// larwe 9/16/06 bugfix split case 0a/0b and changed fallthrough handling
// Case 0a - Return immediately for degenerate case
if (offset == fileinfo->pointer) {
return;
}
// Case 0b - Don't allow the user to seek past the end of the file
if (offset > fileinfo->filelen) {
offset = fileinfo->filelen;
// NOTE NO RETURN HERE!
}
// Case 1 - Simple rewind to start
// Note _intentional_ fallthrough from Case 0b above
if (offset == 0) {
fileinfo->cluster = fileinfo->firstcluster;
fileinfo->pointer = 0;
return; // larwe 9/16/06 +1 bugfix
}
// Case 2 - Seeking backwards. Need to reset and seek forwards
else if (offset < fileinfo->pointer) {
fileinfo->cluster = fileinfo->firstcluster;
fileinfo->pointer = 0;
// NOTE NO RETURN HERE!
}
// Case 3 - Seeking forwards
// Note _intentional_ fallthrough from Case 2 above
// Case 3a - Seek size does not cross cluster boundary -
// very simple case
// larwe 9/16/06 changed .rem to .quot in both div calls, bugfix
if (div(fileinfo->pointer, fileinfo->volinfo->secperclus * SECTOR_SIZE).quot ==
div(fileinfo->pointer + offset, fileinfo->volinfo->secperclus * SECTOR_SIZE).quot) {
fileinfo->pointer = offset;
}
// Case 3b - Seeking across cluster boundary(ies)
else {
// round file pointer down to cluster boundary
fileinfo->pointer = div(fileinfo->pointer, fileinfo->volinfo->secperclus * SECTOR_SIZE).quot *
fileinfo->volinfo->secperclus * SECTOR_SIZE;
// seek by clusters
// larwe 9/30/06 bugfix changed .rem to .quot in both div calls
// canny/reza 5/7 added endcluster related code
// TK 2008-12-18: fixed endcluster calculation
// old: endcluster = div(fileinfo->pointer + offset, fileinfo->volinfo->secperclus * SECTOR_SIZE).quot;
endcluster = div(offset, fileinfo->volinfo->secperclus * SECTOR_SIZE).quot;
while (div(fileinfo->pointer, fileinfo->volinfo->secperclus * SECTOR_SIZE).quot !=endcluster) {
fileinfo->cluster = DFS_GetFAT(fileinfo->volinfo, scratch, &tempint, fileinfo->cluster);
// Abort if there was an error
if (fileinfo->cluster == 0x0ffffff7) {
fileinfo->pointer = 0;
fileinfo->cluster = fileinfo->firstcluster;
return;
}
fileinfo->pointer += SECTOR_SIZE * fileinfo->volinfo->secperclus;
}
// since we know the cluster is right, we have no more work to do
fileinfo->pointer = offset;
}
}
/*
Delete a file
scratch must point to a sector-sized buffer
*/
uint32_t DFS_UnlinkFile(PVOLINFO volinfo, uint8_t *path, uint8_t *scratch)
{
// PDIRENT de = (PDIRENT) scratch;
FILEINFO fi;
uint32_t cache = 0;
uint32_t tempclus = 0;
#ifdef DEBUG_DOSFS
printf("DFS_UnlinkFile\r\n");
#endif
// DFS_OpenFile gives us all the information we need to delete it
if (DFS_OK != DFS_OpenFile(volinfo, path, DFS_READ, scratch, &fi))
return DFS_NOTFOUND;
// First, read the directory sector and delete that entry
if (DFS_ReadSector(volinfo->unit, scratch, fi.dirsector, 1))
return DFS_ERRMISC;
((PDIRENT) scratch)[fi.diroffset].name[0] = 0xe5;
if (DFS_WriteSector(volinfo->unit, scratch, fi.dirsector, 1))
return DFS_ERRMISC;
// Now follow the cluster chain to free the file space
while (!((volinfo->filesystem == FAT12 && fi.firstcluster >= 0x0ff7) ||
(volinfo->filesystem == FAT16 && fi.firstcluster >= 0xfff7) ||
(volinfo->filesystem == FAT32 && fi.firstcluster >= 0x0ffffff7))) {
tempclus = fi.firstcluster;
fi.firstcluster = DFS_GetFAT(volinfo, scratch, &cache, fi.firstcluster);
DFS_SetFAT(volinfo, scratch, &cache, tempclus, 0);
}
return DFS_OK;
}
/*
Write an open file
You must supply a prepopulated FILEINFO as provided by DFS_OpenFile, and a
pointer to a SECTOR_SIZE scratch buffer.
This function updates the successcount field with the number of bytes actually written.
*/
uint32_t DFS_WriteFile(PFILEINFO fileinfo, uint8_t *scratch, uint8_t *buffer, uint32_t *successcount, uint32_t len)
{
uint32_t remain=0;
uint32_t result = DFS_OK;
uint32_t sector=0;
uint32_t byteswritten=0;
#ifdef DEBUG_DOSFS
printf("DFS_WriteFile\r\n");
#endif
// Don't allow writes to a file that's open as readonly
if (!(fileinfo->mode & DFS_WRITE))
return DFS_ERRMISC;
remain = len;
*successcount = 0;
while (remain && result == DFS_OK) {
// This is a bit complicated. The sector we want to read is addressed at a cluster
// granularity by the fileinfo->cluster member. The file pointer tells us how many
// extra sectors to add to that number.
sector = fileinfo->volinfo->dataarea +
((fileinfo->cluster - 2) * fileinfo->volinfo->secperclus) +
div(div(fileinfo->pointer,fileinfo->volinfo->secperclus * SECTOR_SIZE).rem, SECTOR_SIZE).quot;
// Case 1 - File pointer is not on a sector boundary
if (div(fileinfo->pointer, SECTOR_SIZE).rem) {
uint16_t tempsize;
// We always have to go through scratch in this case
result = DFS_ReadSector(fileinfo->volinfo->unit, scratch, sector, 1);
// This is the number of bytes that we don't want to molest in the
// scratch sector just read.
tempsize = div(fileinfo->pointer, SECTOR_SIZE).rem;
// Case 1A - We are writing the entire remainder of the sector. After
// this point, all passes through the read loop will be aligned on a
// sector boundary, which allows us to go through the optimal path
// 2A below.
if (remain >= (uint32_t)SECTOR_SIZE - tempsize) {
memcpy(scratch + tempsize, buffer, SECTOR_SIZE - tempsize);
if (!result)
result = DFS_WriteSector(fileinfo->volinfo->unit, scratch, sector, 1);
byteswritten = SECTOR_SIZE - tempsize;
buffer += SECTOR_SIZE - tempsize;
fileinfo->pointer += SECTOR_SIZE - tempsize;
if (fileinfo->filelen < fileinfo->pointer) {
fileinfo->filelen = fileinfo->pointer;
}
remain -= SECTOR_SIZE - tempsize;
}
// Case 1B - This concludes the file write operation
else {
memcpy(scratch + tempsize, buffer, remain);
if (!result)
result = DFS_WriteSector(fileinfo->volinfo->unit, scratch, sector, 1);
buffer += remain;
fileinfo->pointer += remain;
if (fileinfo->filelen < fileinfo->pointer) {
fileinfo->filelen = fileinfo->pointer;
}
byteswritten = remain;
remain = 0;
}
} // case 1
// Case 2 - File pointer is on sector boundary
else {
// Case 2A - We have at least one more full sector to write and don't have
// to go through the scratch buffer. You could insert optimizations here to
// write multiple sectors at a time, if you were thus inclined. Refer to
// similar notes in DFS_ReadFile.
if (remain >= SECTOR_SIZE) {
result = DFS_WriteSector(fileinfo->volinfo->unit, buffer, sector, 1);
remain -= SECTOR_SIZE;
buffer += SECTOR_SIZE;
fileinfo->pointer += SECTOR_SIZE;
if (fileinfo->filelen < fileinfo->pointer) {
fileinfo->filelen = fileinfo->pointer;
}
byteswritten = SECTOR_SIZE;
}
// Case 2B - We are only writing a partial sector and potentially need to
// go through the scratch buffer.
else {
// If the current file pointer is not yet at or beyond the file
// length, we are writing somewhere in the middle of the file and
// need to load the original sector to do a read-modify-write.
if (fileinfo->pointer < fileinfo->filelen) {
result = DFS_ReadSector(fileinfo->volinfo->unit, scratch, sector, 1);
if (!result) {
memcpy(scratch, buffer, remain);
result = DFS_WriteSector(fileinfo->volinfo->unit, scratch, sector, 1);
}
}
else {
result = DFS_WriteSector(fileinfo->volinfo->unit, buffer, sector, 1);
}
buffer += remain;
fileinfo->pointer += remain;
if (fileinfo->filelen < fileinfo->pointer) {
fileinfo->filelen = fileinfo->pointer;
}
byteswritten = remain;
remain = 0;
}
}
*successcount += byteswritten;
// check to see if we stepped over a cluster boundary
if (div(fileinfo->pointer - byteswritten, fileinfo->volinfo->secperclus * SECTOR_SIZE).quot !=
div(fileinfo->pointer, fileinfo->volinfo->secperclus * SECTOR_SIZE).quot) {
uint32_t lastcluster;
// We've transgressed into another cluster. If we were already at EOF,
// we need to allocate a new cluster.
// An act of minor evil - we use byteswritten as a scratch integer, knowing
// that its value is not used after updating *successcount above
byteswritten = 0;
lastcluster = fileinfo->cluster;
fileinfo->cluster = DFS_GetFAT(fileinfo->volinfo, scratch, &byteswritten, fileinfo->cluster);
// Allocate a new cluster?
if (((fileinfo->volinfo->filesystem == FAT12) && (fileinfo->cluster >= 0xff8)) ||
((fileinfo->volinfo->filesystem == FAT16) && (fileinfo->cluster >= 0xfff8)) ||
((fileinfo->volinfo->filesystem == FAT32) && (fileinfo->cluster >= 0x0ffffff8))) {
uint32_t tempclus;
tempclus = DFS_GetFreeFAT(fileinfo->volinfo, scratch);
byteswritten = 0; // invalidate cache
if (tempclus == 0x0ffffff7)
return DFS_ERRMISC;
// Link new cluster onto file
DFS_SetFAT(fileinfo->volinfo, scratch, &byteswritten, lastcluster, tempclus);
fileinfo->cluster = tempclus;
// Mark newly allocated cluster as end of chain
switch(fileinfo->volinfo->filesystem) {
case FAT12: tempclus = 0xff8; break;
case FAT16: tempclus = 0xfff8; break;
case FAT32: tempclus = 0x0ffffff8; break;
default: return DFS_ERRMISC;
}
DFS_SetFAT(fileinfo->volinfo, scratch, &byteswritten, fileinfo->cluster, tempclus);
result = DFS_OK;
}
// No else clause is required.
}
}
// Update directory entry
if (DFS_ReadSector(fileinfo->volinfo->unit, scratch, fileinfo->dirsector, 1))
return DFS_ERRMISC;
((PDIRENT) scratch)[fileinfo->diroffset].filesize_0 = fileinfo->filelen & 0xff;
((PDIRENT) scratch)[fileinfo->diroffset].filesize_1 = (fileinfo->filelen & 0xff00) >> 8;
((PDIRENT) scratch)[fileinfo->diroffset].filesize_2 = (fileinfo->filelen & 0xff0000) >> 16;
((PDIRENT) scratch)[fileinfo->diroffset].filesize_3 = (fileinfo->filelen & 0xff000000) >> 24;
if (DFS_WriteSector(fileinfo->volinfo->unit, scratch, fileinfo->dirsector, 1))
return DFS_ERRMISC;
return result;
}
/*
// TK: added 2009-02-12
Close a file
No original function of DosFS driver
It has no effect if writing to SD Card, it's only used by the DosFS wrapper in emulation
*/
uint32_t DFS_Close(__attribute__((unused)) PFILEINFO fileinfo)
{
return DFS_OK;
}
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