296 lines
9.3 KiB
C++
296 lines
9.3 KiB
C++
/* Arduino SdFat Library
|
|
* Copyright (C) 2009 by William Greiman
|
|
*
|
|
* This file is part of the Arduino SdFat Library
|
|
*
|
|
* This Library is free software: you can redistribute it and/or modify
|
|
* it under the terms of the GNU General Public License as published by
|
|
* the Free Software Foundation, either version 3 of the License, or
|
|
* (at your option) any later version.
|
|
*
|
|
* This Library is distributed in the hope that it will be useful,
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
* GNU General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU General Public License
|
|
* along with the Arduino SdFat Library. If not, see
|
|
* <http://www.gnu.org/licenses/>.
|
|
*/
|
|
#include "SdFat.h"
|
|
//------------------------------------------------------------------------------
|
|
// raw block cache
|
|
// init cacheBlockNumber_to invalid SD block number
|
|
uint32_t SdVolume::cacheBlockNumber_ = 0XFFFFFFFF;
|
|
cache_t SdVolume::cacheBuffer_; // 512 byte cache for Sd2Card
|
|
Sd2Card* SdVolume::sdCard_; // pointer to SD card object
|
|
uint8_t SdVolume::cacheDirty_ = 0; // cacheFlush() will write block if true
|
|
uint32_t SdVolume::cacheMirrorBlock_ = 0; // mirror block for second FAT
|
|
//------------------------------------------------------------------------------
|
|
// find a contiguous group of clusters
|
|
uint8_t SdVolume::allocContiguous(uint32_t count, uint32_t* curCluster) {
|
|
// start of group
|
|
uint32_t bgnCluster;
|
|
|
|
// flag to save place to start next search
|
|
uint8_t setStart;
|
|
|
|
// set search start cluster
|
|
if (*curCluster) {
|
|
// try to make file contiguous
|
|
bgnCluster = *curCluster + 1;
|
|
|
|
// don't save new start location
|
|
setStart = false;
|
|
} else {
|
|
// start at likely place for free cluster
|
|
bgnCluster = allocSearchStart_;
|
|
|
|
// save next search start if one cluster
|
|
setStart = 1 == count;
|
|
}
|
|
// end of group
|
|
uint32_t endCluster = bgnCluster;
|
|
|
|
// last cluster of FAT
|
|
uint32_t fatEnd = clusterCount_ + 1;
|
|
|
|
// search the FAT for free clusters
|
|
for (uint32_t n = 0;; n++, endCluster++) {
|
|
// can't find space checked all clusters
|
|
if (n >= clusterCount_) return false;
|
|
|
|
// past end - start from beginning of FAT
|
|
if (endCluster > fatEnd) {
|
|
bgnCluster = endCluster = 2;
|
|
}
|
|
uint32_t f;
|
|
if (!fatGet(endCluster, &f)) return false;
|
|
|
|
if (f != 0) {
|
|
// cluster in use try next cluster as bgnCluster
|
|
bgnCluster = endCluster + 1;
|
|
} else if ((endCluster - bgnCluster + 1) == count) {
|
|
// done - found space
|
|
break;
|
|
}
|
|
}
|
|
// mark end of chain
|
|
if (!fatPutEOC(endCluster)) return false;
|
|
|
|
// link clusters
|
|
while (endCluster > bgnCluster) {
|
|
if (!fatPut(endCluster - 1, endCluster)) return false;
|
|
endCluster--;
|
|
}
|
|
if (*curCluster != 0) {
|
|
// connect chains
|
|
if (!fatPut(*curCluster, bgnCluster)) return false;
|
|
}
|
|
// return first cluster number to caller
|
|
*curCluster = bgnCluster;
|
|
|
|
// remember possible next free cluster
|
|
if (setStart) allocSearchStart_ = bgnCluster + 1;
|
|
|
|
return true;
|
|
}
|
|
//------------------------------------------------------------------------------
|
|
uint8_t SdVolume::cacheFlush(void) {
|
|
if (cacheDirty_) {
|
|
if (!sdCard_->writeBlock(cacheBlockNumber_, cacheBuffer_.data)) {
|
|
return false;
|
|
}
|
|
// mirror FAT tables
|
|
if (cacheMirrorBlock_) {
|
|
if (!sdCard_->writeBlock(cacheMirrorBlock_, cacheBuffer_.data)) {
|
|
return false;
|
|
}
|
|
cacheMirrorBlock_ = 0;
|
|
}
|
|
cacheDirty_ = 0;
|
|
}
|
|
return true;
|
|
}
|
|
//------------------------------------------------------------------------------
|
|
uint8_t SdVolume::cacheRawBlock(uint32_t blockNumber, uint8_t action) {
|
|
if (cacheBlockNumber_ != blockNumber) {
|
|
if (!cacheFlush()) return false;
|
|
if (!sdCard_->readBlock(blockNumber, cacheBuffer_.data)) return false;
|
|
cacheBlockNumber_ = blockNumber;
|
|
}
|
|
cacheDirty_ |= action;
|
|
return true;
|
|
}
|
|
//------------------------------------------------------------------------------
|
|
// cache a zero block for blockNumber
|
|
uint8_t SdVolume::cacheZeroBlock(uint32_t blockNumber) {
|
|
if (!cacheFlush()) return false;
|
|
|
|
// loop take less flash than memset(cacheBuffer_.data, 0, 512);
|
|
for (uint16_t i = 0; i < 512; i++) {
|
|
cacheBuffer_.data[i] = 0;
|
|
}
|
|
cacheBlockNumber_ = blockNumber;
|
|
cacheSetDirty();
|
|
return true;
|
|
}
|
|
//------------------------------------------------------------------------------
|
|
// return the size in bytes of a cluster chain
|
|
uint8_t SdVolume::chainSize(uint32_t cluster, uint32_t* size) const {
|
|
uint32_t s = 0;
|
|
do {
|
|
if (!fatGet(cluster, &cluster)) return false;
|
|
s += 512UL << clusterSizeShift_;
|
|
} while (!isEOC(cluster));
|
|
*size = s;
|
|
return true;
|
|
}
|
|
//------------------------------------------------------------------------------
|
|
// Fetch a FAT entry
|
|
uint8_t SdVolume::fatGet(uint32_t cluster, uint32_t* value) const {
|
|
if (cluster > (clusterCount_ + 1)) return false;
|
|
uint32_t lba = fatStartBlock_;
|
|
lba += fatType_ == 16 ? cluster >> 8 : cluster >> 7;
|
|
if (lba != cacheBlockNumber_) {
|
|
if (!cacheRawBlock(lba, CACHE_FOR_READ)) return false;
|
|
}
|
|
if (fatType_ == 16) {
|
|
*value = cacheBuffer_.fat16[cluster & 0XFF];
|
|
} else {
|
|
*value = cacheBuffer_.fat32[cluster & 0X7F] & FAT32MASK;
|
|
}
|
|
return true;
|
|
}
|
|
//------------------------------------------------------------------------------
|
|
// Store a FAT entry
|
|
uint8_t SdVolume::fatPut(uint32_t cluster, uint32_t value) {
|
|
// error if reserved cluster
|
|
if (cluster < 2) return false;
|
|
|
|
// error if not in FAT
|
|
if (cluster > (clusterCount_ + 1)) return false;
|
|
|
|
// calculate block address for entry
|
|
uint32_t lba = fatStartBlock_;
|
|
lba += fatType_ == 16 ? cluster >> 8 : cluster >> 7;
|
|
|
|
if (lba != cacheBlockNumber_) {
|
|
if (!cacheRawBlock(lba, CACHE_FOR_READ)) return false;
|
|
}
|
|
// store entry
|
|
if (fatType_ == 16) {
|
|
cacheBuffer_.fat16[cluster & 0XFF] = value;
|
|
} else {
|
|
cacheBuffer_.fat32[cluster & 0X7F] = value;
|
|
}
|
|
cacheSetDirty();
|
|
|
|
// mirror second FAT
|
|
if (fatCount_ > 1) cacheMirrorBlock_ = lba + blocksPerFat_;
|
|
return true;
|
|
}
|
|
//------------------------------------------------------------------------------
|
|
// free a cluster chain
|
|
uint8_t SdVolume::freeChain(uint32_t cluster) {
|
|
// clear free cluster location
|
|
allocSearchStart_ = 2;
|
|
|
|
do {
|
|
uint32_t next;
|
|
if (!fatGet(cluster, &next)) return false;
|
|
|
|
// free cluster
|
|
if (!fatPut(cluster, 0)) return false;
|
|
|
|
cluster = next;
|
|
} while (!isEOC(cluster));
|
|
|
|
return true;
|
|
}
|
|
//------------------------------------------------------------------------------
|
|
/**
|
|
* Initialize a FAT volume.
|
|
*
|
|
* \param[in] dev The SD card where the volume is located.
|
|
*
|
|
* \param[in] part The partition to be used. Legal values for \a part are
|
|
* 1-4 to use the corresponding partition on a device formatted with
|
|
* a MBR, Master Boot Record, or zero if the device is formatted as
|
|
* a super floppy with the FAT boot sector in block zero.
|
|
*
|
|
* \return The value one, true, is returned for success and
|
|
* the value zero, false, is returned for failure. Reasons for
|
|
* failure include not finding a valid partition, not finding a valid
|
|
* FAT file system in the specified partition or an I/O error.
|
|
*/
|
|
uint8_t SdVolume::init(Sd2Card* dev, uint8_t part) {
|
|
uint32_t volumeStartBlock = 0;
|
|
sdCard_ = dev;
|
|
// if part == 0 assume super floppy with FAT boot sector in block zero
|
|
// if part > 0 assume mbr volume with partition table
|
|
if (part) {
|
|
if (part > 4)return false;
|
|
if (!cacheRawBlock(volumeStartBlock, CACHE_FOR_READ)) return false;
|
|
part_t* p = &cacheBuffer_.mbr.part[part-1];
|
|
if ((p->boot & 0X7F) !=0 ||
|
|
p->totalSectors < 100 ||
|
|
p->firstSector == 0) {
|
|
// not a valid partition
|
|
return false;
|
|
}
|
|
volumeStartBlock = p->firstSector;
|
|
}
|
|
if (!cacheRawBlock(volumeStartBlock, CACHE_FOR_READ)) return false;
|
|
bpb_t* bpb = &cacheBuffer_.fbs.bpb;
|
|
if (bpb->bytesPerSector != 512 ||
|
|
bpb->fatCount == 0 ||
|
|
bpb->reservedSectorCount == 0 ||
|
|
bpb->sectorsPerCluster == 0) {
|
|
// not valid FAT volume
|
|
return false;
|
|
}
|
|
fatCount_ = bpb->fatCount;
|
|
blocksPerCluster_ = bpb->sectorsPerCluster;
|
|
|
|
// determine shift that is same as multiply by blocksPerCluster_
|
|
clusterSizeShift_ = 0;
|
|
while (blocksPerCluster_ != (1 << clusterSizeShift_)) {
|
|
// error if not power of 2
|
|
if (clusterSizeShift_++ > 7) return false;
|
|
}
|
|
blocksPerFat_ = bpb->sectorsPerFat16 ?
|
|
bpb->sectorsPerFat16 : bpb->sectorsPerFat32;
|
|
|
|
fatStartBlock_ = volumeStartBlock + bpb->reservedSectorCount;
|
|
|
|
// count for FAT16 zero for FAT32
|
|
rootDirEntryCount_ = bpb->rootDirEntryCount;
|
|
|
|
// directory start for FAT16 dataStart for FAT32
|
|
rootDirStart_ = fatStartBlock_ + bpb->fatCount * blocksPerFat_;
|
|
|
|
// data start for FAT16 and FAT32
|
|
dataStartBlock_ = rootDirStart_ + ((32 * bpb->rootDirEntryCount + 511)/512);
|
|
|
|
// total blocks for FAT16 or FAT32
|
|
uint32_t totalBlocks = bpb->totalSectors16 ?
|
|
bpb->totalSectors16 : bpb->totalSectors32;
|
|
// total data blocks
|
|
clusterCount_ = totalBlocks - (dataStartBlock_ - volumeStartBlock);
|
|
|
|
// divide by cluster size to get cluster count
|
|
clusterCount_ >>= clusterSizeShift_;
|
|
|
|
// FAT type is determined by cluster count
|
|
if (clusterCount_ < 4085) {
|
|
fatType_ = 12;
|
|
} else if (clusterCount_ < 65525) {
|
|
fatType_ = 16;
|
|
} else {
|
|
rootDirStart_ = bpb->fat32RootCluster;
|
|
fatType_ = 32;
|
|
}
|
|
return true;
|
|
}
|