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597 lines
14 KiB
C++
597 lines
14 KiB
C++
/* FatLib Library
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* Copyright (C) 2013 by William Greiman
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*
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* This file is part of the FatLib Library
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*
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* This Library is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This Library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with the FatLib Library. If not, see
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* <http://www.gnu.org/licenses/>.
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*/
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#include <string.h>
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#include "FatVolume.h"
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//------------------------------------------------------------------------------
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cache_t* FatCache::read(uint32_t lbn, uint8_t option) {
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if (m_lbn != lbn) {
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if (!sync()) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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if (!(option & CACHE_OPTION_NO_READ)) {
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if (!m_vol->readBlock(lbn, m_block.data)) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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}
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m_status = 0;
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m_lbn = lbn;
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}
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m_status |= option & CACHE_STATUS_MASK;
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return &m_block;
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fail:
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return 0;
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}
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//------------------------------------------------------------------------------
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bool FatCache::sync() {
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if (m_status & CACHE_STATUS_DIRTY) {
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if (!m_vol->writeBlock(m_lbn, m_block.data)) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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// mirror second FAT
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if (m_status & CACHE_STATUS_MIRROR_FAT) {
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uint32_t lbn = m_lbn + m_vol->blocksPerFat();
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if (!m_vol->writeBlock(lbn, m_block.data)) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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}
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m_status &= ~CACHE_STATUS_DIRTY;
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}
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return true;
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fail:
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return false;
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}
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//------------------------------------------------------------------------------
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bool FatVolume::allocateCluster(uint32_t current, uint32_t* next) {
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uint32_t find = current ? current : m_allocSearchStart;
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uint32_t start = find;
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while (1) {
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find++;
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// If at end of FAT go to beginning of FAT.
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if (find > m_lastCluster) {
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find = 2;
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}
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uint32_t f;
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int8_t fg = fatGet(find, &f);
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if (fg < 0) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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if (fg && f == 0) {
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break;
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}
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if (find == start) {
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// Can't find space checked all clusters.
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DBG_FAIL_MACRO;
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goto fail;
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}
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}
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// mark end of chain
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if (!fatPutEOC(find)) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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if (current) {
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// link clusters
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if (!fatPut(current, find)) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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} else {
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// Remember place for search start.
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m_allocSearchStart = find;
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}
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updateFreeClusterCount(-1);
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*next = find;
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return true;
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fail:
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return false;
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}
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//------------------------------------------------------------------------------
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// find a contiguous group of clusters
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bool FatVolume::allocContiguous(uint32_t count, uint32_t* firstCluster) {
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// flag to save place to start next search
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bool setStart = true;
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// start of group
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uint32_t bgnCluster;
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// end of group
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uint32_t endCluster;
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// Start at cluster after last allocated cluster.
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uint32_t startCluster = m_allocSearchStart;
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endCluster = bgnCluster = startCluster + 1;
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// search the FAT for free clusters
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while (1) {
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// If past end - start from beginning of FAT.
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if (endCluster > m_lastCluster) {
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bgnCluster = endCluster = 2;
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}
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uint32_t f;
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int8_t fg = fatGet(endCluster, &f);
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if (fg < 0) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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if (f || fg == 0) {
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// cluster in use try next cluster as bgnCluster
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bgnCluster = endCluster + 1;
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// don't update search start if unallocated clusters before endCluster.
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if (bgnCluster != endCluster) {
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setStart = false;
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}
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} else if ((endCluster - bgnCluster + 1) == count) {
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// done - found space
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break;
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}
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// Can't find space if all clusters checked.
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if (startCluster == endCluster) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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endCluster++;
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}
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// remember possible next free cluster
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if (setStart) {
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m_allocSearchStart = endCluster + 1;
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}
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// mark end of chain
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if (!fatPutEOC(endCluster)) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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// link clusters
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while (endCluster > bgnCluster) {
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if (!fatPut(endCluster - 1, endCluster)) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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endCluster--;
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}
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// Maintain count of free clusters.
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updateFreeClusterCount(-count);
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// return first cluster number to caller
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*firstCluster = bgnCluster;
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return true;
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fail:
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return false;
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}
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//------------------------------------------------------------------------------
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uint32_t FatVolume::clusterFirstBlock(uint32_t cluster) const {
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return m_dataStartBlock + ((cluster - 2) << m_clusterSizeShift);
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}
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//------------------------------------------------------------------------------
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// Fetch a FAT entry - return -1 error, 0 EOC, else 1.
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int8_t FatVolume::fatGet(uint32_t cluster, uint32_t* value) {
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uint32_t lba;
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uint32_t next;
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cache_t* pc;
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// error if reserved cluster of beyond FAT
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DBG_HALT_IF(cluster < 2 || cluster > m_lastCluster);
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if (fatType() == 32) {
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lba = m_fatStartBlock + (cluster >> 7);
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pc = cacheFetchFat(lba, FatCache::CACHE_FOR_READ);
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if (!pc) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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next = pc->fat32[cluster & 0X7F] & FAT32MASK;
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goto done;
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}
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if (fatType() == 16) {
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lba = m_fatStartBlock + ((cluster >> 8) & 0XFF);
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pc = cacheFetchFat(lba, FatCache::CACHE_FOR_READ);
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if (!pc) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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next = pc->fat16[cluster & 0XFF];
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goto done;
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}
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if (FAT12_SUPPORT && fatType() == 12) {
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uint16_t index = cluster;
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index += index >> 1;
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lba = m_fatStartBlock + (index >> 9);
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pc = cacheFetchFat(lba, FatCache::CACHE_FOR_READ);
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if (!pc) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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index &= 0X1FF;
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uint16_t tmp = pc->data[index];
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index++;
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if (index == 512) {
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pc = cacheFetchFat(lba + 1, FatCache::CACHE_FOR_READ);
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if (!pc) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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index = 0;
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}
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tmp |= pc->data[index] << 8;
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next = cluster & 1 ? tmp >> 4 : tmp & 0XFFF;
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goto done;
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} else {
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DBG_FAIL_MACRO;
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goto fail;
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}
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done:
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if (isEOC(next)) {
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return 0;
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}
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*value = next;
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return 1;
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fail:
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return -1;
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}
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//------------------------------------------------------------------------------
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// Store a FAT entry
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bool FatVolume::fatPut(uint32_t cluster, uint32_t value) {
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uint32_t lba;
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cache_t* pc;
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// error if reserved cluster of beyond FAT
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DBG_HALT_IF(cluster < 2 || cluster > m_lastCluster);
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if (fatType() == 32) {
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lba = m_fatStartBlock + (cluster >> 7);
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pc = cacheFetchFat(lba, FatCache::CACHE_FOR_WRITE);
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if (!pc) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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pc->fat32[cluster & 0X7F] = value;
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return true;
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}
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if (fatType() == 16) {
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lba = m_fatStartBlock + ((cluster >> 8) & 0XFF);
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pc = cacheFetchFat(lba, FatCache::CACHE_FOR_WRITE);
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if (!pc) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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pc->fat16[cluster & 0XFF] = value;
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return true;
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}
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if (FAT12_SUPPORT && fatType() == 12) {
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uint16_t index = cluster;
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index += index >> 1;
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lba = m_fatStartBlock + (index >> 9);
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pc = cacheFetchFat(lba, FatCache::CACHE_FOR_WRITE);
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if (!pc) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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index &= 0X1FF;
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uint8_t tmp = value;
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if (cluster & 1) {
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tmp = (pc->data[index] & 0XF) | tmp << 4;
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}
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pc->data[index] = tmp;
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index++;
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if (index == 512) {
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lba++;
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index = 0;
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pc = cacheFetchFat(lba, FatCache::CACHE_FOR_WRITE);
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if (!pc) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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}
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tmp = value >> 4;
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if (!(cluster & 1)) {
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tmp = ((pc->data[index] & 0XF0)) | tmp >> 4;
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}
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pc->data[index] = tmp;
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return true;
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} else {
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DBG_FAIL_MACRO;
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goto fail;
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}
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fail:
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return false;
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}
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//------------------------------------------------------------------------------
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// free a cluster chain
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bool FatVolume::freeChain(uint32_t cluster) {
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uint32_t next;
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int8_t fg;
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do {
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fg = fatGet(cluster, &next);
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if (fg < 0) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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// free cluster
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if (!fatPut(cluster, 0)) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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// Add one to count of free clusters.
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updateFreeClusterCount(1);
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if (cluster < m_allocSearchStart) {
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m_allocSearchStart = cluster;
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}
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cluster = next;
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} while (fg);
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return true;
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fail:
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return false;
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}
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//------------------------------------------------------------------------------
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int32_t FatVolume::freeClusterCount() {
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#if MAINTAIN_FREE_CLUSTER_COUNT
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if (m_freeClusterCount >= 0) {
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return m_freeClusterCount;
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}
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#endif // MAINTAIN_FREE_CLUSTER_COUNT
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uint32_t free = 0;
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uint32_t lba;
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uint32_t todo = m_lastCluster + 1;
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uint16_t n;
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if (FAT12_SUPPORT && fatType() == 12) {
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for (unsigned i = 2; i < todo; i++) {
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uint32_t c;
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int8_t fg = fatGet(i, &c);
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if (fg < 0) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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if (fg && c == 0) {
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free++;
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}
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}
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} else if (fatType() == 16 || fatType() == 32) {
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lba = m_fatStartBlock;
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while (todo) {
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cache_t* pc = cacheFetchFat(lba++, FatCache::CACHE_FOR_READ);
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if (!pc) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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n = fatType() == 16 ? 256 : 128;
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if (todo < n) {
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n = todo;
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}
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if (fatType() == 16) {
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for (uint16_t i = 0; i < n; i++) {
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if (pc->fat16[i] == 0) {
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free++;
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}
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}
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} else {
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for (uint16_t i = 0; i < n; i++) {
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if (pc->fat32[i] == 0) {
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free++;
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}
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}
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}
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todo -= n;
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}
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} else {
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// invalid FAT type
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DBG_FAIL_MACRO;
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goto fail;
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}
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setFreeClusterCount(free);
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return free;
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fail:
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return -1;
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}
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//------------------------------------------------------------------------------
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bool FatVolume::init(uint8_t part) {
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uint32_t clusterCount;
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uint32_t totalBlocks;
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uint32_t volumeStartBlock = 0;
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fat32_boot_t* fbs;
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cache_t* pc;
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uint8_t tmp;
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m_fatType = 0;
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m_allocSearchStart = 1;
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m_cache.init(this);
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#if USE_SEPARATE_FAT_CACHE
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m_fatCache.init(this);
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#endif // USE_SEPARATE_FAT_CACHE
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// if part == 0 assume super floppy with FAT boot sector in block zero
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// if part > 0 assume mbr volume with partition table
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if (part) {
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if (part > 4) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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pc = cacheFetchData(0, FatCache::CACHE_FOR_READ);
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if (!pc) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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part_t* p = &pc->mbr.part[part - 1];
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if ((p->boot & 0X7F) != 0 || p->firstSector == 0) {
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// not a valid partition
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DBG_FAIL_MACRO;
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goto fail;
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}
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volumeStartBlock = p->firstSector;
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}
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pc = cacheFetchData(volumeStartBlock, FatCache::CACHE_FOR_READ);
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if (!pc) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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fbs = &(pc->fbs32);
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if (fbs->bytesPerSector != 512 ||
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fbs->fatCount != 2 ||
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fbs->reservedSectorCount == 0) {
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// not valid FAT volume
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DBG_FAIL_MACRO;
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goto fail;
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}
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m_blocksPerCluster = fbs->sectorsPerCluster;
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m_clusterBlockMask = m_blocksPerCluster - 1;
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// determine shift that is same as multiply by m_blocksPerCluster
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m_clusterSizeShift = 0;
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for (tmp = 1; m_blocksPerCluster != tmp; tmp <<= 1, m_clusterSizeShift++) {
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if (tmp == 0) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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}
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m_blocksPerFat = fbs->sectorsPerFat16 ?
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fbs->sectorsPerFat16 : fbs->sectorsPerFat32;
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m_fatStartBlock = volumeStartBlock + fbs->reservedSectorCount;
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// count for FAT16 zero for FAT32
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m_rootDirEntryCount = fbs->rootDirEntryCount;
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// directory start for FAT16 dataStart for FAT32
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m_rootDirStart = m_fatStartBlock + 2 * m_blocksPerFat;
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// data start for FAT16 and FAT32
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m_dataStartBlock = m_rootDirStart + ((32 * fbs->rootDirEntryCount + 511)/512);
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// total blocks for FAT16 or FAT32
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totalBlocks = fbs->totalSectors16 ?
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fbs->totalSectors16 : fbs->totalSectors32;
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// total data blocks
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clusterCount = totalBlocks - (m_dataStartBlock - volumeStartBlock);
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|
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// divide by cluster size to get cluster count
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clusterCount >>= m_clusterSizeShift;
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m_lastCluster = clusterCount + 1;
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// Indicate unknown number of free clusters.
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setFreeClusterCount(-1);
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// FAT type is determined by cluster count
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if (clusterCount < 4085) {
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m_fatType = 12;
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if (!FAT12_SUPPORT) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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} else if (clusterCount < 65525) {
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m_fatType = 16;
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} else {
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m_rootDirStart = fbs->fat32RootCluster;
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m_fatType = 32;
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}
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return true;
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fail:
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return false;
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}
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//------------------------------------------------------------------------------
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bool FatVolume::wipe(print_t* pr) {
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cache_t* cache;
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uint16_t count;
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uint32_t lbn;
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if (!fatType()) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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cache = cacheClear();
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if (!cache) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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memset(cache->data, 0, 512);
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// Zero root.
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if (fatType() == 32) {
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lbn = clusterFirstBlock(m_rootDirStart);
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count = m_blocksPerCluster;
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} else {
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lbn = m_rootDirStart;
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count = m_rootDirEntryCount/16;
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}
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for (uint32_t n = 0; n < count; n++) {
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if (!writeBlock(lbn + n, cache->data)) {
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DBG_FAIL_MACRO;
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goto fail;
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}
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}
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// Clear FATs.
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count = 2*m_blocksPerFat;
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lbn = m_fatStartBlock;
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for (uint32_t nb = 0; nb < count; nb++) {
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if (pr && (nb & 0XFF) == 0) {
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pr->write('.');
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}
|
|
if (!writeBlock(lbn + nb, cache->data)) {
|
|
DBG_FAIL_MACRO;
|
|
goto fail;
|
|
}
|
|
}
|
|
// Reserve first two clusters.
|
|
if (fatType() == 32) {
|
|
cache->fat32[0] = 0x0FFFFFF8;
|
|
cache->fat32[1] = 0x0FFFFFFF;
|
|
} else if (fatType() == 16) {
|
|
cache->fat16[0] = 0XFFF8;
|
|
cache->fat16[1] = 0XFFFF;
|
|
} else if (FAT12_SUPPORT && fatType() == 12) {
|
|
cache->fat32[0] = 0XFFFFF8;
|
|
} else {
|
|
DBG_FAIL_MACRO;
|
|
goto fail;
|
|
}
|
|
if (!writeBlock(m_fatStartBlock, cache->data) ||
|
|
!writeBlock(m_fatStartBlock + m_blocksPerFat, cache->data)) {
|
|
DBG_FAIL_MACRO;
|
|
goto fail;
|
|
}
|
|
if (fatType() == 32) {
|
|
// Reserve root cluster.
|
|
if (!fatPutEOC(m_rootDirStart) || !cacheSync()) {
|
|
DBG_FAIL_MACRO;
|
|
goto fail;
|
|
}
|
|
}
|
|
if (pr) {
|
|
pr->write('\r');
|
|
pr->write('\n');
|
|
}
|
|
m_fatType = 0;
|
|
return true;
|
|
|
|
fail:
|
|
m_fatType = 0;
|
|
return false;
|
|
}
|