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Diffstat (limited to 'Sprinter/SdVolume.cpp')
| -rw-r--r-- | Sprinter/SdVolume.cpp | 295 |
1 files changed, 295 insertions, 0 deletions
diff --git a/Sprinter/SdVolume.cpp b/Sprinter/SdVolume.cpp new file mode 100644 index 0000000..3c1e641 --- /dev/null +++ b/Sprinter/SdVolume.cpp @@ -0,0 +1,295 @@ +/* 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; +} |