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Subversion Repositories openrisc_2011-10-31
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/dosfs.c
0,0 → 1,1492
/* |
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. |
*/ |
|
/* |
@2010, adam.edvardsson@orsoc.se |
Added local copy of the functions, |
div_t, memcmp2,strcpy2,strcmp2. The one from the string library is not comatible |
|
*/ |
|
|
//#include <string.h> |
//#include <stdlib.h> |
//#include "or32_utils.h" |
#include "dosfs.h" |
#include "sdc.h" |
|
#include "common.h" |
#include "support.h" |
#include "uart.h" |
|
|
|
unsigned long int init_fat(VOLINFO *vis){ |
|
|
|
unsigned char sector[SECTOR_SIZE]; |
unsigned long int pstart,psize, i,fisz; |
unsigned char pactive, ptype; |
VOLINFO vi; |
|
|
//uart_init(DEFAULT_UART); |
printf("FAT INIT START\n"); |
memCardInit(); |
|
|
pstart = DFS_GetPtnStart(0, sector, 0, &pactive, &ptype, &psize); |
if (pstart == 0xffffffff) { |
printf("Cannot find first partition\n"); |
return -1; |
} |
|
printf("Partition 0 start sector 0x%-08.8lX active %-02.2hX type %-02.2hX size %-08.8lX\n", pstart, pactive, ptype, psize); |
|
if (DFS_GetVolInfo(0, sector, pstart, &vi)) { |
printf("Error getting volume information\n"); |
return -1; |
} |
|
|
|
|
*vis=vi; |
|
|
|
} |
|
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unsigned long int DFS_ReadSector(unsigned char unit, unsigned char *buffer, unsigned long int sector, unsigned long int count) |
{ |
|
unsigned long int block_add = 0; |
int i ; |
|
|
|
for (i=0; i<count; i++){ |
block_add=sector+i; |
DBGA("\n readSector %u, block_addr %u \n",sector,block_add); |
setup_bd_transfer(READ_OP, block_add , buffer); |
if (finnish_bd_transfer() == FALSE) |
return 0xff; |
|
} |
|
return 0; |
|
} |
|
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unsigned long int DFS_WriteSector(unsigned char unit, unsigned char *buffer, unsigned long int sector, unsigned long int count) |
{ |
|
|
unsigned long int block_add = 0; |
unsigned char scr[SECTOR_SIZE]; |
|
block_add=sector; |
DBGA("\n writeSector %u, block_addr2 %u \n",sector,block_add); |
setup_bd_transfer(WRITE_OP, block_add , buffer); |
|
if (finnish_bd_transfer() == FALSE){ |
printf("TRANSACTION FAILED, Buffer %x \n", buffer); |
|
//reset_card(); |
// sd_wait_rsp(); |
// SD_REG(SD_SOFTWARE_RST)=1; |
|
//SD_REG(SD_SOFTWARE_RST)=0; |
|
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DBGA("FREE BD TX/RX: 0x%x \n", SD_REG(BD_STATUS) ); |
|
|
DBGA("TRY READ SECTOR \n"); |
setup_bd_transfer(READ_OP, 526571008 , scr); |
finnish_bd_transfer(); |
DBGA("PRINT test wreite to 526571008 \n"); |
setup_bd_transfer(WRITE_OP, 526571008 , scr); |
finnish_bd_transfer(); |
|
setup_bd_transfer(WRITE_OP, block_add , buffer); |
if (finnish_bd_transfer() == FALSE){ |
printf("TRANSACTION FAILED AGAIN!, Buffer %x \n", buffer); |
return 0xff; |
} |
|
} |
|
|
return 0; |
|
} |
|
/* |
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. |
*/ |
|
|
unsigned long int DFS_GetPtnStart(unsigned char unit, unsigned char *scratchsector, unsigned char pnum, unsigned char *pactive, unsigned char *pptype, unsigned long int *psize) |
{ |
unsigned long int result; |
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; |
} |
|
result = (unsigned long int) mbr->ptable[pnum].start_0 | |
(((unsigned long int) mbr->ptable[pnum].start_1) << 8) | |
(((unsigned long int) mbr->ptable[pnum].start_2) << 16) | |
(((unsigned long int) mbr->ptable[pnum].start_3) << 24); |
|
|
//unsigned char active; // 0x80 if partition active |
//unsigned char start_h; // starting head |
//unsigned char start_cs_l; // starting cylinder and sector (low byte) |
//unsigned char start_cs_h; // starting cylinder and sector (high byte) |
|
printf("active 0:%x 1:%x 2:%x 3:%x \n", mbr->ptable[pnum].active, mbr->ptable[pnum].start_h, mbr->ptable[pnum].start_cs_l,mbr->ptable[pnum].start_cs_h); |
|
printf("start 0:%x 1:%x 2:%x 3:%x \n", mbr->ptable[pnum].start_0, mbr->ptable[pnum].start_1,mbr->ptable[pnum].start_2,mbr->ptable[pnum].start_3); |
if (pactive) |
*pactive = mbr->ptable[pnum].active; |
|
if (pptype) |
*pptype = mbr->ptable[pnum].type; |
|
if (psize){ |
*psize = (unsigned long int) mbr->ptable[pnum].size_0 | |
(((unsigned long int) mbr->ptable[pnum].size_1) << 8) | |
(((unsigned long int) mbr->ptable[pnum].size_2) << 16) | |
(((unsigned long int) mbr->ptable[pnum].size_3) << 24); |
printf("size 0:%x 1:%x 2:%x 3:%x \n", mbr->ptable[pnum].size_0, mbr->ptable[pnum].size_1,mbr->ptable[pnum].size_2,mbr->ptable[pnum].size_3); |
} |
|
return result; |
} |
|
|
|
ldiv_t ldiv (long int numer, long int denom) |
{ |
ldiv_t result; |
|
result.quot = numer / denom; |
result.rem = numer % denom; |
|
/* The ANSI standard says that |QUOT| <= |NUMER / DENOM|, where |
NUMER / DENOM is to be computed in infinite precision. In |
other words, we should always truncate the quotient towards |
zero, never -infinity. Machine division and remainer may |
work either way when one or both of NUMER or DENOM is |
negative. If only one is negative and QUOT has been |
truncated towards -infinity, REM will have the same sign as |
DENOM and the opposite sign of NUMER; if both are negative |
and QUOT has been truncated towards -infinity, REM will be |
positive (will have the opposite sign of NUMER). These are |
considered `wrong'. If both are NUM and DENOM are positive, |
RESULT will always be positive. This all boils down to: if |
NUMER >= 0, but REM < 0, we got the wrong answer. In that |
case, to get the right answer, add 1 to QUOT and subtract |
DENOM from REM. */ |
|
if (numer >= 0 && result.rem < 0) |
{ |
++result.quot; |
result.rem -= denom; |
} |
|
return result; |
} |
|
div_t div ( int numer, int denom) |
{ |
div_t result; |
|
result.quot = numer / denom; |
result.rem = numer % denom; |
|
/* The ANSI standard says that |QUOT| <= |NUMER / DENOM|, where |
NUMER / DENOM is to be computed in infinite precision. In |
other words, we should always truncate the quotient towards |
zero, never -infinity. Machine division and remainer may |
work either way when one or both of NUMER or DENOM is |
negative. If only one is negative and QUOT has been |
truncated towards -infinity, REM will have the same sign as |
DENOM and the opposite sign of NUMER; if both are negative |
and QUOT has been truncated towards -infinity, REM will be |
positive (will have the opposite sign of NUMER). These are |
considered `wrong'. If both are NUM and DENOM are positive, |
RESULT will always be positive. This all boils down to: if |
NUMER >= 0, but REM < 0, we got the wrong answer. In that |
case, to get the right answer, add 1 to QUOT and subtract |
DENOM from REM. */ |
|
if (numer >= 0 && result.rem < 0) |
{ |
++result.quot; |
result.rem -= denom; |
} |
|
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. |
*/ |
unsigned long int DFS_GetVolInfo(unsigned char unit, unsigned char *scratchsector, unsigned long int startsector, PVOLINFO volinfo) |
{ |
PLBR lbr = (PLBR) scratchsector; |
volinfo->unit = unit; |
volinfo->startsector = startsector; |
|
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 = (unsigned short) lbr->bpb.reserved_l | |
(((unsigned short) lbr->bpb.reserved_h) << 8); |
|
volinfo->numsecs = (unsigned short) lbr->bpb.sectors_s_l | |
(((unsigned short) lbr->bpb.sectors_s_h) << 8); |
|
if (!volinfo->numsecs) |
volinfo->numsecs = (unsigned long int) lbr->bpb.sectors_l_0 | |
(((unsigned long int) lbr->bpb.sectors_l_1) << 8) | |
(((unsigned long int) lbr->bpb.sectors_l_2) << 16) | |
(((unsigned long int) 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 = (unsigned short) lbr->bpb.secperfat_l | |
(((unsigned short) lbr->bpb.secperfat_h) << 8); |
if (!volinfo->secperfat) { |
volinfo->secperfat = (unsigned long int) lbr->ebpb.ebpb32.fatsize_0 | |
(((unsigned long int) lbr->ebpb.ebpb32.fatsize_1) << 8) | |
(((unsigned long int) lbr->ebpb.ebpb32.fatsize_2) << 16) | |
(((unsigned long int) 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 = (unsigned short) lbr->bpb.rootentries_l | |
(((unsigned short) 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 = (unsigned long int) lbr->ebpb.ebpb32.root_0 | |
(((unsigned long int) lbr->ebpb.ebpb32.root_1) << 8) | |
(((unsigned long int) lbr->ebpb.ebpb32.root_2) << 16) | |
(((unsigned long int) 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. |
*/ |
unsigned long int DFS_GetFAT(PVOLINFO volinfo, unsigned char *scratch, unsigned long int *scratchcache, unsigned long int cluster) |
{ |
unsigned long int offset, sector, result; |
|
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 = (unsigned long int) 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 |= ((unsigned long int) scratch[0]) << 8; |
} |
else { |
result = (unsigned long int) scratch[offset] | |
((unsigned long int) scratch[offset+1]) << 8; |
} |
if (cluster & 1) |
result = result >> 4; |
else |
result = result & 0xfff; |
} |
else if (volinfo->filesystem == FAT16) { |
result = (unsigned long int) scratch[offset] | |
((unsigned long int) scratch[offset+1]) << 8; |
} |
else if (volinfo->filesystem == FAT32) { |
result = ((unsigned long int) scratch[offset] | |
((unsigned long int) scratch[offset+1]) << 8 | |
((unsigned long int) scratch[offset+2]) << 16 | |
((unsigned long int) 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. |
*/ |
unsigned long int DFS_SetFAT(PVOLINFO volinfo, unsigned char *scratch, unsigned long int *scratchcache, unsigned long int cluster, unsigned long int new_contents) |
{ |
unsigned long int offset, sector, result; |
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++; |
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 |
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. |
*/ |
unsigned char *DFS_CanonicalToDir(unsigned char *dest, unsigned char *src) |
{ |
unsigned char *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 |
*/ |
unsigned long int DFS_GetFreeFAT(PVOLINFO volinfo, unsigned char *scratch) |
{ |
unsigned long int i, result = 0xffffffff, scratchcache = 0; |
|
// 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) |
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. |
*/ |
unsigned long int DFS_OpenDir(PVOLINFO volinfo, unsigned char *dirname, PDIRINFO dirinfo) |
{ |
// Default behavior is a regular search for existing entries |
dirinfo->flags = 0; |
|
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 { |
unsigned char tmpfn[12]; |
unsigned char *ptr = dirname; |
unsigned long int 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 && memcmp2(de.name, tmpfn, 11)); |
|
if (!memcmp2(de.name, tmpfn, 11) && ((de.attr & ATTR_DIRECTORY) == ATTR_DIRECTORY)) { |
if (volinfo->filesystem == FAT32) { |
dirinfo->currentcluster = (unsigned long int) de.startclus_l_l | |
((unsigned long int) de.startclus_l_h) << 8 | |
((unsigned long int) de.startclus_h_l) << 16 | |
((unsigned long int) de.startclus_h_h) << 24; |
} |
else { |
dirinfo->currentcluster = (unsigned long int) de.startclus_l_l | |
((unsigned long int) 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 (!memcmp2(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 |
*/ |
unsigned long int DFS_GetNext(PVOLINFO volinfo, PDIRINFO dirinfo, PDIRENT dirent) |
{ |
unsigned long int tempint; // required by DFS_GetFAT |
|
// 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 (dirinfo->flags & DFS_DI_BLANKENT) |
return DFS_OK; |
else |
return DFS_EOF; |
} |
|
if (dirent->name[0] == 0xe5) // handle deleted file entries |
dirent->name[0] = 0; |
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 |
*/ |
unsigned long int DFS_GetFreeDirEnt(PVOLINFO volinfo, unsigned char *path, PDIRINFO di, PDIRENT de) |
{ |
unsigned long int tempclus,i; |
|
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. |
*/ |
unsigned long int DFS_OpenFile(PVOLINFO volinfo, unsigned char *path, unsigned char mode, unsigned char *scratch, PFILEINFO fileinfo) |
{ |
unsigned char tmppath[MAX_PATH]; |
unsigned char filename[12]; |
unsigned char *p; |
DIRINFO di; |
DIRENT de; |
|
// 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. |
strcpy2((char *) tmppath, (char *) path); |
tmppath[MAX_PATH - 1] = 0; |
if (strcmp2((char *) path,(char *) tmppath)) { |
return DFS_PATHLEN; |
} |
|
|
// strip leading path separators |
while (tmppath[0] == DIR_SEPARATOR) |
strcpy2((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 (!memcmp2(de.name, filename, 11)) { |
// You can't use this function call to open a directory. |
if (de.attr & ATTR_DIRECTORY) |
return DFS_NOTFOUND; |
printf("get enxt \n"); |
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 = (unsigned long int) de.startclus_l_l | |
((unsigned long int) de.startclus_l_h) << 8 | |
((unsigned long int) de.startclus_h_l) << 16 | |
((unsigned long int) de.startclus_h_h) << 24; |
} |
else { |
fileinfo->cluster = (unsigned long int) de.startclus_l_l | |
((unsigned long int) de.startclus_l_h) << 8; |
} |
fileinfo->firstcluster = fileinfo->cluster; |
fileinfo->filelen = (unsigned long int) de.filesize_0 | |
((unsigned long int) de.filesize_1) << 8 | |
((unsigned long int) de.filesize_2) << 16 | |
((unsigned long int) 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) { |
unsigned long int cluster, temp; |
|
// 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. |
*/ |
unsigned long int DFS_ReadFile(PFILEINFO fileinfo, unsigned char *scratch, unsigned char *buffer, unsigned long int *successcount, unsigned long int len) |
{ |
unsigned long int remain; |
unsigned long int result = DFS_OK; |
unsigned long int sector; |
unsigned long int bytesread; |
|
// 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) { |
|
unsigned short 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, unsigned long int offset, unsigned char *scratch) |
{ |
unsigned long int tempint; |
|
// 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 |
while (div(fileinfo->pointer, fileinfo->volinfo->secperclus * SECTOR_SIZE).quot != |
div(fileinfo->pointer + offset, fileinfo->volinfo->secperclus * SECTOR_SIZE).quot) { |
|
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 |
*/ |
unsigned long int DFS_UnlinkFile(PVOLINFO volinfo, unsigned char *path, unsigned char *scratch) |
{ |
PDIRENT de = (PDIRENT) scratch; |
FILEINFO fi; |
unsigned long int cache = 0; |
unsigned long int tempclus; |
|
// 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. |
*/ |
unsigned long int DFS_WriteFile(PFILEINFO fileinfo, unsigned char *scratch, unsigned char *buffer, unsigned long int *successcount, unsigned long int len) |
{ |
unsigned long int remain; |
unsigned long int result = DFS_OK; |
unsigned long int sector; |
unsigned long int byteswritten; |
|
// 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) { |
unsigned short tempsize; |
printf("CASE 1 \n"); |
// 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 >= 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 { |
printf("CASE 1B \n"); |
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 { |
printf("CASE 2 \n"); |
// 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 { |
printf("CASE 2B \n"); |
// 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; |
printf("Writen byte %d \n", *successcount ); |
// 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) { |
unsigned long int 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))) { |
unsigned long int 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; |
} |
|
int memcmp2(const void* s1, const void* s2,size_t n) |
{ |
const unsigned char *p1 = s1, *p2 = s2; |
while(n--) |
if( *p1 != *p2 ) |
return *p1 - *p2; |
else |
*p1++,*p2++; |
return 0; |
} |
|
char *strcpy2(char *dest, char* src) |
{ |
char *ret = dest; |
while (*dest++ = *src++) |
; |
return ret; |
} |
|
int strcmp2(const char* s1, const char* s2) |
{ |
while(*s1 && (*s1==*s2)) |
s1++,s2++; |
return *(const unsigned char*)s1-*(const unsigned char*)s2; |
} |
dosfs.c
Property changes :
Added: svn:executable
## -0,0 +1 ##
+*
\ No newline at end of property
Index: Makefile
===================================================================
--- Makefile (revision 375)
+++ Makefile (revision 389)
@@ -3,7 +3,7 @@
LIB = common_o.o
-OBJS = common.o support.o cprintf.o screen.o font.o ctype.o string.o spincursor.o
+OBJS = common.o support.o cprintf.o screen.o font.o ctype.o string.o spincursor.o dosfs.o
SOBJS = or32.o
all: $(LIB)
@@ -19,4 +19,4 @@
sinclude .depend
-#########################################################################
+