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git-svn-id: svn://svn.openpilot.org/OpenPilot/trunk@1798 ebee16cc-31ac-478f-84a7-5cbb03baadba
1337 lines
62 KiB
C
1337 lines
62 KiB
C
/*
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DOSFS Embedded FAT-Compatible Filesystem
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(C) 2005 Lewin A.R.W. Edwards (sysadm@zws.com)
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You are permitted to modify and/or use this code in your own projects without
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payment of royalty, regardless of the license(s) you choose for those projects.
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You cannot re-copyright or restrict use of the code as released by Lewin Edwards.
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*/
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//#include "common.h"
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#include <string.h>
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#include <stdlib.h>
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//#include "fat.h"
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#define div(a,b) ldiv(a,b)
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#include "dosfs.h"
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/*
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Get starting sector# of specified partition on drive #unit
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NOTE: This code ASSUMES an MBR on the disk.
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scratchsector should point to a SECTOR_SIZE scratch area
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Returns 0xffffffff for any error.
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If pactive is non-NULL, this function also returns the partition active flag.
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If pptype is non-NULL, this function also returns the partition type.
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If psize is non-NULL, this function also returns the partition size.
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*/
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uint32_t DFS_GetPtnStart(uint8_t unit, uint8_t *scratchsector, uint8_t pnum, uint8_t *pactive, uint8_t *pptype, uint32_t *psize)
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{
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uint32_t result=0;
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PMBR mbr = (PMBR) scratchsector;
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// DOS ptable supports maximum 4 partitions
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if (pnum > 3)
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return DFS_ERRMISC;
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// Read MBR from target media
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if (DFS_ReadSector(unit,scratchsector,0,1)) {
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return DFS_ERRMISC;
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}
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// check if jump to boot, VBR
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if(mbr->bootcode[0]==0xEB || mbr->bootcode[0]==0xE9){
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// MBR is actually VBR
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return 0;
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}
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result = (uint32_t) mbr->ptable[pnum].start_0 |
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(((uint32_t) mbr->ptable[pnum].start_1) << 8) |
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(((uint32_t) mbr->ptable[pnum].start_2) << 16) |
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(((uint32_t) mbr->ptable[pnum].start_3) << 24);
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if (pactive)
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*pactive = mbr->ptable[pnum].active;
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if (pptype)
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*pptype = mbr->ptable[pnum].type;
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if (psize)
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*psize = (uint32_t) mbr->ptable[pnum].size_0 |
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(((uint32_t) mbr->ptable[pnum].size_1) << 8) |
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(((uint32_t) mbr->ptable[pnum].size_2) << 16) |
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(((uint32_t) mbr->ptable[pnum].size_3) << 24);
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return result;
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}
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/*
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Retrieve volume info from BPB and store it in a VOLINFO structure
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You must provide the unit and starting sector of the filesystem, and
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a pointer to a sector buffer for scratch
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Attempts to read BPB and glean information about the FS from that.
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Returns 0 OK, nonzero for any error.
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*/
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uint32_t DFS_GetVolInfo(uint8_t unit, uint8_t *scratchsector, uint32_t startsector, PVOLINFO volinfo)
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{
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PLBR lbr = (PLBR) scratchsector;
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volinfo->unit = unit;
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volinfo->startsector = startsector;
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#ifdef DEBUG_DOSFS
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printf("DFS_GetVolInfo\r\n");
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#endif
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if(DFS_ReadSector(unit,scratchsector,startsector,1))
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return DFS_ERRMISC;
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// tag: OEMID, refer dosfs.h
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// strncpy(volinfo->oemid, lbr->oemid, 8);
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// volinfo->oemid[8] = 0;
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volinfo->secperclus = lbr->bpb.secperclus;
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volinfo->reservedsecs = (uint16_t) lbr->bpb.reserved_l |
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(((uint16_t) lbr->bpb.reserved_h) << 8);
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volinfo->numsecs = (uint16_t) lbr->bpb.sectors_s_l |
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(((uint16_t) lbr->bpb.sectors_s_h) << 8);
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if (!volinfo->numsecs)
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volinfo->numsecs = (uint32_t) lbr->bpb.sectors_l_0 |
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(((uint32_t) lbr->bpb.sectors_l_1) << 8) |
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(((uint32_t) lbr->bpb.sectors_l_2) << 16) |
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(((uint32_t) lbr->bpb.sectors_l_3) << 24);
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// If secperfat is 0, we must be in a FAT32 volume; get secperfat
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// from the FAT32 EBPB. The volume label and system ID string are also
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// in different locations for FAT12/16 vs FAT32.
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volinfo->secperfat = (uint16_t) lbr->bpb.secperfat_l |
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(((uint16_t) lbr->bpb.secperfat_h) << 8);
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if (!volinfo->secperfat) {
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volinfo->secperfat = (uint32_t) lbr->ebpb.ebpb32.fatsize_0 |
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(((uint32_t) lbr->ebpb.ebpb32.fatsize_1) << 8) |
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(((uint32_t) lbr->ebpb.ebpb32.fatsize_2) << 16) |
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(((uint32_t) lbr->ebpb.ebpb32.fatsize_3) << 24);
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memcpy(volinfo->label, lbr->ebpb.ebpb32.label, 11);
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volinfo->label[11] = 0;
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// tag: OEMID, refer dosfs.h
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// memcpy(volinfo->system, lbr->ebpb.ebpb32.system, 8);
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// volinfo->system[8] = 0;
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}
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else {
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memcpy(volinfo->label, lbr->ebpb.ebpb.label, 11);
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volinfo->label[11] = 0;
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// tag: OEMID, refer dosfs.h
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// memcpy(volinfo->system, lbr->ebpb.ebpb.system, 8);
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// volinfo->system[8] = 0;
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}
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// note: if rootentries is 0, we must be in a FAT32 volume.
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volinfo->rootentries = (uint16_t) lbr->bpb.rootentries_l |
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(((uint16_t) lbr->bpb.rootentries_h) << 8);
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// after extracting raw info we perform some useful precalculations
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volinfo->fat1 = startsector + volinfo->reservedsecs;
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// The calculation below is designed to round up the root directory size for FAT12/16
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// and to simply ignore the root directory for FAT32, since it's a normal, expandable
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// file in that situation.
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if (volinfo->rootentries) {
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volinfo->rootdir = volinfo->fat1 + (volinfo->secperfat * 2);
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volinfo->dataarea = volinfo->rootdir + (((volinfo->rootentries * 32) + (SECTOR_SIZE - 1)) / SECTOR_SIZE);
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}
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else {
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volinfo->dataarea = volinfo->fat1 + (volinfo->secperfat * 2);
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volinfo->rootdir = (uint32_t) lbr->ebpb.ebpb32.root_0 |
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(((uint32_t) lbr->ebpb.ebpb32.root_1) << 8) |
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(((uint32_t) lbr->ebpb.ebpb32.root_2) << 16) |
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(((uint32_t) lbr->ebpb.ebpb32.root_3) << 24);
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}
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// Calculate number of clusters in data area and infer FAT type from this information.
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volinfo->numclusters = (volinfo->numsecs - volinfo->dataarea) / volinfo->secperclus;
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if (volinfo->numclusters < 4085)
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volinfo->filesystem = FAT12;
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else if (volinfo->numclusters < 65525)
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volinfo->filesystem = FAT16;
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else
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volinfo->filesystem = FAT32;
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return DFS_OK;
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}
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/*
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Fetch FAT entry for specified cluster number
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You must provide a scratch buffer for one sector (SECTOR_SIZE) and a populated VOLINFO
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Returns a FAT32 BAD_CLUSTER value for any error, otherwise the contents of the desired
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FAT entry.
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scratchcache should point to a UINT32. This variable caches the physical sector number
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last read into the scratch buffer for performance enhancement reasons.
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*/
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uint32_t DFS_GetFAT(PVOLINFO volinfo, uint8_t *scratch, uint32_t *scratchcache, uint32_t cluster)
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{
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uint32_t offset=0, sector=0, result=0;
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#ifdef DEBUG_DOSFS
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printf("DFS_GetFAT\r\n");
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#endif
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if (volinfo->filesystem == FAT12) {
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offset = cluster + (cluster / 2);
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}
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else if (volinfo->filesystem == FAT16) {
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offset = cluster * 2;
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}
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else if (volinfo->filesystem == FAT32) {
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offset = cluster * 4;
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}
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else
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return 0x0ffffff7; // FAT32 bad cluster
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// at this point, offset is the BYTE offset of the desired sector from the start
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// of the FAT. Calculate the physical sector containing this FAT entry.
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sector = ldiv(offset, SECTOR_SIZE).quot + volinfo->fat1;
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// If this is not the same sector we last read, then read it into RAM
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if (sector != *scratchcache) {
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if(DFS_ReadSector(volinfo->unit, scratch, sector, 1)) {
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// avoid anyone assuming that this cache value is still valid, which
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// might cause disk corruption
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*scratchcache = 0;
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return 0x0ffffff7; // FAT32 bad cluster
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}
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*scratchcache = sector;
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}
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// At this point, we "merely" need to extract the relevant entry.
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// This is easy for FAT16 and FAT32, but a royal PITA for FAT12 as a single entry
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// may span a sector boundary. The normal way around this is always to read two
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// FAT sectors, but that luxury is (by design intent) unavailable to DOSFS.
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offset = ldiv(offset, SECTOR_SIZE).rem;
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if (volinfo->filesystem == FAT12) {
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// Special case for sector boundary - Store last byte of current sector.
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// Then read in the next sector and put the first byte of that sector into
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// the high byte of result.
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if (offset == SECTOR_SIZE - 1) {
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result = (uint32_t) scratch[offset];
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sector++;
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if(DFS_ReadSector(volinfo->unit, scratch, sector, 1)) {
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// avoid anyone assuming that this cache value is still valid, which
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// might cause disk corruption
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*scratchcache = 0;
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return 0x0ffffff7; // FAT32 bad cluster
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}
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*scratchcache = sector;
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// Thanks to Claudio Leonel for pointing out this missing line.
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result |= ((uint32_t) scratch[0]) << 8;
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}
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else {
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result = (uint32_t) scratch[offset] |
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((uint32_t) scratch[offset+1]) << 8;
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}
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if (cluster & 1)
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result = result >> 4;
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else
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result = result & 0xfff;
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}
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else if (volinfo->filesystem == FAT16) {
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result = (uint32_t) scratch[offset] |
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((uint32_t) scratch[offset+1]) << 8;
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}
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else if (volinfo->filesystem == FAT32) {
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result = ((uint32_t) scratch[offset] |
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((uint32_t) scratch[offset+1]) << 8 |
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((uint32_t) scratch[offset+2]) << 16 |
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((uint32_t) scratch[offset+3]) << 24) & 0x0fffffff;
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}
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else
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result = 0x0ffffff7; // FAT32 bad cluster
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return result;
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}
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/*
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Set FAT entry for specified cluster number
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You must provide a scratch buffer for one sector (SECTOR_SIZE) and a populated VOLINFO
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Returns DFS_ERRMISC for any error, otherwise DFS_OK
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scratchcache should point to a UINT32. This variable caches the physical sector number
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last read into the scratch buffer for performance enhancement reasons.
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NOTE: This code is HIGHLY WRITE-INEFFICIENT, particularly for flash media. Considerable
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performance gains can be realized by caching the sector. However this is difficult to
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achieve on FAT12 without requiring 2 sector buffers of scratch space, and it is a design
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requirement of this code to operate on a single 512-byte scratch.
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If you are operating DOSFS over flash, you are strongly advised to implement a writeback
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cache in your physical I/O driver. This will speed up your code significantly and will
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also conserve power and flash write life.
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*/
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uint32_t DFS_SetFAT(PVOLINFO volinfo, uint8_t *scratch, uint32_t *scratchcache, uint32_t cluster, uint32_t new_contents)
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{
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uint32_t offset=0, sector=0, result=0;
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#ifdef DEBUG_DOSFS
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printf("DFS_SetFAT (%lu->%lu)\r\n",cluster,new_contents);
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#endif
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if (volinfo->filesystem == FAT12) {
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offset = cluster + (cluster / 2);
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new_contents &=0xfff;
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}
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else if (volinfo->filesystem == FAT16) {
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offset = cluster * 2;
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new_contents &=0xffff;
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}
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else if (volinfo->filesystem == FAT32) {
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offset = cluster * 4;
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new_contents &=0x0fffffff; // FAT32 is really "FAT28"
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}
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else
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return DFS_ERRMISC;
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// at this point, offset is the BYTE offset of the desired sector from the start
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// of the FAT. Calculate the physical sector containing this FAT entry.
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sector = ldiv(offset, SECTOR_SIZE).quot + volinfo->fat1;
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// If this is not the same sector we last read, then read it into RAM
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if (sector != *scratchcache) {
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if(DFS_ReadSector(volinfo->unit, scratch, sector, 1)) {
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// avoid anyone assuming that this cache value is still valid, which
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// might cause disk corruption
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*scratchcache = 0;
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return DFS_ERRMISC;
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}
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*scratchcache = sector;
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}
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// At this point, we "merely" need to extract the relevant entry.
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// This is easy for FAT16 and FAT32, but a royal PITA for FAT12 as a single entry
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// may span a sector boundary. The normal way around this is always to read two
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// FAT sectors, but that luxury is (by design intent) unavailable to DOSFS.
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offset = ldiv(offset, SECTOR_SIZE).rem;
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if (volinfo->filesystem == FAT12) {
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// If this is an odd cluster, pre-shift the desired new contents 4 bits to
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// make the calculations below simpler
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if (cluster & 1)
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new_contents = new_contents << 4;
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// Special case for sector boundary
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if (offset == SECTOR_SIZE - 1) {
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// Odd cluster: High 12 bits being set
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if (cluster & 1) {
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scratch[offset] = (scratch[offset] & 0x0f) | (new_contents & 0xf0);
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}
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// Even cluster: Low 12 bits being set
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else {
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scratch[offset] = new_contents & 0xff;
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}
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result = DFS_WriteSector(volinfo->unit, scratch, *scratchcache, 1);
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// mirror the FAT into copy 2
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if (DFS_OK == result)
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result = DFS_WriteSector(volinfo->unit, scratch, (*scratchcache)+volinfo->secperfat, 1);
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// If we wrote that sector OK, then read in the subsequent sector
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// and poke the first byte with the remainder of this FAT entry.
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if (DFS_OK == result) {
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// *scratchcache++;
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++*scratchcache; // TK: to avoid warning "value computed is not used"
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result = DFS_ReadSector(volinfo->unit, scratch, *scratchcache, 1);
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if (DFS_OK == result) {
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// Odd cluster: High 12 bits being set
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if (cluster & 1) {
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scratch[0] = new_contents & 0xff00;
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}
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// Even cluster: Low 12 bits being set
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else {
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scratch[0] = (scratch[0] & 0xf0) | (new_contents & 0x0f);
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}
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result = DFS_WriteSector(volinfo->unit, scratch, *scratchcache, 1);
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// mirror the FAT into copy 2
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if (DFS_OK == result)
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result = DFS_WriteSector(volinfo->unit, scratch, (*scratchcache)+volinfo->secperfat, 1);
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}
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else {
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// avoid anyone assuming that this cache value is still valid, which
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// might cause disk corruption
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*scratchcache = 0;
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}
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}
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} // if (offset == SECTOR_SIZE - 1)
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// Not a sector boundary. But we still have to worry about if it's an odd
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// or even cluster number.
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else {
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// Odd cluster: High 12 bits being set
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if (cluster & 1) {
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scratch[offset] = (scratch[offset] & 0x0f) | (new_contents & 0xf0);
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scratch[offset+1] = new_contents & 0xff00;
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}
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// Even cluster: Low 12 bits being set
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else {
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scratch[offset] = new_contents & 0xff;
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scratch[offset+1] = (scratch[offset+1] & 0xf0) | (new_contents & 0x0f);
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}
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result = DFS_WriteSector(volinfo->unit, scratch, *scratchcache, 1);
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// mirror the FAT into copy 2
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if (DFS_OK == result)
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result = DFS_WriteSector(volinfo->unit, scratch, (*scratchcache)+volinfo->secperfat, 1);
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}
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}
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else if (volinfo->filesystem == FAT16) {
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scratch[offset] = (new_contents & 0xff);
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scratch[offset+1] = (new_contents & 0xff00) >> 8;
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result = DFS_WriteSector(volinfo->unit, scratch, *scratchcache, 1);
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// mirror the FAT into copy 2 - XXX
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if (DFS_OK == result)
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result = DFS_WriteSector(volinfo->unit, scratch, (*scratchcache)+volinfo->secperfat, 1);
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}
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else if (volinfo->filesystem == FAT32) {
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scratch[offset] = (new_contents & 0xff);
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scratch[offset+1] = (new_contents & 0xff00) >> 8;
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scratch[offset+2] = (new_contents & 0xff0000) >> 16;
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scratch[offset+3] = (scratch[offset+3] & 0xf0) | ((new_contents & 0x0f000000) >> 24);
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// Note well from the above: Per Microsoft's guidelines we preserve the upper
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// 4 bits of the FAT32 cluster value. It's unclear what these bits will be used
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// for; in every example I've encountered they are always zero.
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result = DFS_WriteSector(volinfo->unit, scratch, *scratchcache, 1);
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// mirror the FAT into copy 2
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if (DFS_OK == result)
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result = DFS_WriteSector(volinfo->unit, scratch, (*scratchcache)+volinfo->secperfat, 1);
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}
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else
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result = DFS_ERRMISC;
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return result;
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}
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/*
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Convert a filename element from canonical (8.3) to directory entry (11) form
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src must point to the first non-separator character.
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dest must point to a 12-byte buffer.
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*/
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uint8_t *DFS_CanonicalToDir(uint8_t *dest, uint8_t *src)
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{
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uint8_t *destptr = dest;
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memset(dest, ' ', 11);
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dest[11] = 0;
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while (*src && (*src != DIR_SEPARATOR) && (destptr - dest < 11)) {
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if (*src >= 'a' && *src <='z') {
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*destptr++ = (*src - 'a') + 'A';
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src++;
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}
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else if (*src == '.') {
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src++;
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destptr = dest + 8;
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}
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else {
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*destptr++ = *src++;
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}
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}
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return dest;
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}
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/*
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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 >= 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(PFILEINFO fileinfo)
|
|
{
|
|
return DFS_OK;
|
|
}
|
|
|