/modules/usb/usbhdfsd/fat_driver.c

//---------------------------------------------------------------------------
//File name:    fat_driver.c
//---------------------------------------------------------------------------
#include <stdio.h>
#include <errno.h>

#ifdef WIN32
#include <malloc.h>
#include <memory.h>
#include <string.h>
#else
#include <sysclib.h>
//#include <sys/stat.h>

#include <thbase.h>
#include <sysmem.h>
#endif

#include <usbhdfsd.h>
#include "usbhd_common.h"
#include "scache.h"
#include "fat_driver.h"
#include "fat.h"
#include "mass_stor.h"

//#define DEBUG  //comment out this line when not debugging

#include "mass_debug.h"

#define READ_SECTOR(d, a, b)	scache_readSector((d)->cache, (a), (void **)&b)

#define NUM_DRIVES 10
static fat_driver* g_fatd[NUM_DRIVES];

//---------------------------------------------------------------------------
int InitFAT(void)
{
    int i;
	int ret = 0;
    for (i = 0; i < NUM_DRIVES; ++i)
        g_fatd[i] = NULL;
    return ret;
}

//---------------------------------------------------------------------------
int strEqual(const unsigned char *s1, const unsigned char* s2) {
    unsigned char u1, u2;
    for (;;) {
		u1 = *s1++;
		u2 = *s2++;
		if (u1 >64 && u1 < 91)  u1+=32;
		if (u2 >64 && u2 < 91)  u2+=32;

		if (u1 != u2) {
			return -1;
		}
		if (u1 == '\0') {
		    return 0;
		}
    }
}

/*

   0x321, 0xABC

     byte| byte| byte|
   +--+--+--+--+--+--+
   |2 |1 |C |3 |A |B |
   +--+--+--+--+--+--+

*/

//---------------------------------------------------------------------------
unsigned int fat_getClusterRecord12(unsigned char* buf, int type) {
	if (type) { //1
		return ((buf[1]<< 4) + (buf[0] >>4));
	} else { // 0
		return (((buf[1] & 0x0F) << 8) + buf[0]);
	}
}

//---------------------------------------------------------------------------
// Get Cluster chain into <buf> buffer
// returns:
// 0    :if buf is full (bufSize entries) and more chain entries exist
// 1-n  :number of filled entries of the buf
// -1   :error
//---------------------------------------------------------------------------
//for fat12
/* fat12 cluster records can overlap the edge of the sector so we need to detect and maintain
   these cases
*/
static int fat_getClusterChain12(fat_driver* fatd, unsigned int cluster, unsigned int* buf, unsigned int bufSize, int startFlag) {
	int ret;
	unsigned int i, recordOffset, fatSector, lastFatSector;
	unsigned char xbuf[4], sectorSpan, cont;
	unsigned char* sbuf = NULL; //sector buffer

	cont = 1;
	lastFatSector = -1;
	i = 0;
	if (startFlag) {
		buf[i] = cluster; //store first cluster
		i++;
	}
	while(i < bufSize && cont) {
		recordOffset = (cluster * 3) / 2; //offset of the cluster record (in bytes) from the FAT start
		fatSector = recordOffset / fatd->partBpb.sectorSize;
		sectorSpan = 0;
		if ((recordOffset % fatd->partBpb.sectorSize) == (fatd->partBpb.sectorSize - 1)) {
			sectorSpan = 1;
		}
		if (lastFatSector !=  fatSector || sectorSpan) {
			ret = READ_SECTOR(fatd->dev, fatd->partBpb.partStart + fatd->partBpb.resSectors + fatSector, sbuf);
			if (ret < 0) {
				XPRINTF("USBHDFSD: Read fat12 sector failed! sector=%u! \n", fatd->partBpb.partStart + fatd->partBpb.resSectors + fatSector );
				return -EIO;
			}
			lastFatSector = fatSector;

			if (sectorSpan) {
				xbuf[0] = sbuf[fatd->partBpb.sectorSize - 2];
				xbuf[1] = sbuf[fatd->partBpb.sectorSize - 1];
				ret = READ_SECTOR(fatd->dev, fatd->partBpb.partStart + fatd->partBpb.resSectors + fatSector + 1, sbuf);
				if (ret < 0) {
					XPRINTF("USBHDFSD: Read fat12 sector failed sector=%u! \n", fatd->partBpb.partStart + fatd->partBpb.resSectors + fatSector + 1);
					return -EIO;
				}
				xbuf[2] = sbuf[0];
				xbuf[3] = sbuf[1];
			}
		}
		if (sectorSpan) { // use xbuf as source buffer
			cluster = fat_getClusterRecord12(xbuf + (recordOffset % fatd->partBpb.sectorSize) - (fatd->partBpb.sectorSize-2), cluster % 2);
		} else { // use sector buffer as source buffer
			cluster = fat_getClusterRecord12(sbuf + (recordOffset % fatd->partBpb.sectorSize), cluster % 2);
		}

		if ((cluster & 0xFFF) >= 0xFF8) {
			cont = 0; //continue = false
		} else {
			buf[i] = cluster & 0xFFF;
			i++;
		}
	}
	return i;
}


//---------------------------------------------------------------------------
//for fat16
static int fat_getClusterChain16(fat_driver* fatd, unsigned int cluster, unsigned int* buf, unsigned int bufSize, int startFlag) {
	int ret;
	unsigned int i, indexCount, fatSector, lastFatSector;
	unsigned char cont;
	unsigned char* sbuf = NULL; //sector buffer

	cont = 1;
	indexCount = fatd->partBpb.sectorSize / 2; //FAT16->2, FAT32->4
	lastFatSector = -1;
	i = 0;
	if (startFlag) {
		buf[i] = cluster; //store first cluster
		i++;
	}
	while(i < bufSize && cont) {
		fatSector = cluster / indexCount;
		if (lastFatSector !=  fatSector) {
			ret = READ_SECTOR(fatd->dev, fatd->partBpb.partStart + fatd->partBpb.resSectors + fatSector,  sbuf);
			if (ret < 0) {
				XPRINTF("USBHDFSD: Read fat16 sector failed! sector=%u! \n", fatd->partBpb.partStart + fatd->partBpb.resSectors + fatSector );
				return -EIO;
			}

			lastFatSector = fatSector;
		}
		cluster = getI16(sbuf + ((cluster % indexCount) * 2));
		if ((cluster & 0xFFFF) >= 0xFFF8) {
			cont = 0; //continue = false
		} else {
			buf[i] = cluster & 0xFFFF;
			i++;
		}
	}
	return i;
}

//---------------------------------------------------------------------------
//for fat32
static int fat_getClusterChain32(fat_driver* fatd, unsigned int cluster, unsigned int* buf, unsigned int bufSize, int startFlag) {
	int ret;
	unsigned int i, indexCount, fatSector, lastFatSector;
	unsigned char cont;
	unsigned char* sbuf = NULL; //sector buffer

	cont = 1;
	indexCount = fatd->partBpb.sectorSize / 4; //FAT16->2, FAT32->4
	lastFatSector = -1;
	i = 0;
	if (startFlag) {
		buf[i] = cluster; //store first cluster
		i++;
	}
	while(i < bufSize && cont) {
		fatSector = cluster / indexCount;
		if (lastFatSector !=  fatSector) {
			ret = READ_SECTOR(fatd->dev, fatd->partBpb.partStart + fatd->partBpb.resSectors + fatSector,  sbuf);
			if (ret < 0) {
				XPRINTF("USBHDFSD: Read fat32 sector failed sector=%u! \n", fatd->partBpb.partStart + fatd->partBpb.resSectors + fatSector );
				return -EIO;
			}

			lastFatSector = fatSector;
		}
		cluster = getI32(sbuf + ((cluster % indexCount) * 4));
		if ((cluster & 0xFFFFFFF) >= 0xFFFFFF8) {
			cont = 0; //continue = false
		} else {
			buf[i] = cluster & 0xFFFFFFF;
			i++;
		}
	}
	return i;
}

//---------------------------------------------------------------------------
int fat_getClusterChain(fat_driver* fatd, unsigned int cluster, unsigned int* buf, unsigned int bufSize, int startFlag) {

	if (cluster == fatd->lastChainCluster) {
		return fatd->lastChainResult;
	}

	switch (fatd->partBpb.fatType) {
		case FAT12: fatd->lastChainResult = fat_getClusterChain12(fatd, cluster, buf, bufSize, startFlag); break;
		case FAT16: fatd->lastChainResult = fat_getClusterChain16(fatd, cluster, buf, bufSize, startFlag); break;
		case FAT32: fatd->lastChainResult = fat_getClusterChain32(fatd, cluster, buf, bufSize, startFlag); break;
	}
	fatd->lastChainCluster = cluster;
	return fatd->lastChainResult;
}

//---------------------------------------------------------------------------
void fat_invalidateLastChainResult(fat_driver* fatd)
{
	fatd->lastChainCluster  = 0;
}

//---------------------------------------------------------------------------
static void fat_determineFatType(fat_bpb* partBpb) {
	unsigned int sector, clusterCount;

	//get sector of cluster 0
	sector = fat_cluster2sector(partBpb, 0);
	//remove partition start sector to get BR+FAT+ROOT_DIR sector count
	sector -= partBpb->partStart;
	sector = partBpb->sectorCount - sector;
	clusterCount = sector / partBpb->clusterSize;
	//XPRINTF("USBHDFSD: Data cluster count = %u \n", clusterCount);

	if (clusterCount < 4085) {
		partBpb->fatType = FAT12;
	} else
	if (clusterCount < 65525) {
		partBpb->fatType = FAT16;
	} else {
		partBpb->fatType = FAT32;
	}
}

//---------------------------------------------------------------------------
static int fat_getPartitionBootSector(mass_dev* dev, unsigned int sector, fat_bpb* partBpb) {
	fat_raw_bpb* bpb_raw; //fat16, fat12
	fat32_raw_bpb* bpb32_raw; //fat32
	int ret;
	unsigned char* sbuf = NULL; //sector buffer

	ret = READ_SECTOR(dev, sector, sbuf); //read partition boot sector (first sector on partition)
	if (ret < 0) {
		XPRINTF("USBHDFSD: Read partition boot sector failed sector=%u! \n", sector);
		return -EIO;
	}

	bpb_raw = (fat_raw_bpb*) sbuf;
	bpb32_raw = (fat32_raw_bpb*) sbuf;

	//set fat common properties
	partBpb->sectorSize = getI16(bpb_raw->sectorSize);
	partBpb->clusterSize = bpb_raw->clusterSize;
	partBpb->resSectors = getI16(bpb_raw->resSectors);
	partBpb->fatCount = bpb_raw->fatCount;
	partBpb->rootSize = getI16(bpb_raw->rootSize);
	partBpb->fatSize = getI16(bpb_raw->fatSize);
	partBpb->trackSize = getI16(bpb_raw->trackSize);
	partBpb->headCount = getI16(bpb_raw->headCount);
	partBpb->sectorCount = getI16(bpb_raw->sectorCountO);
	if (partBpb->sectorCount == 0) {
		partBpb->sectorCount = getI32(bpb_raw->sectorCount); // large partition
	}
	partBpb->partStart = sector;
	partBpb->rootDirStart = partBpb->partStart + (partBpb->fatCount * partBpb->fatSize) + partBpb->resSectors;
	for (ret = 0; ret < 8; ret++) {
		partBpb->fatId[ret] = bpb_raw->fatId[ret];
	}
	partBpb->fatId[ret] = 0;
	partBpb->rootDirCluster = 0;
	partBpb->dataStart = partBpb->rootDirStart + (partBpb->rootSize / (partBpb->sectorSize >> 5));

	fat_determineFatType(partBpb);

	//fat32 specific info
	if (partBpb->fatType == FAT32 && partBpb->fatSize == 0) {
		partBpb->fatSize = getI32(bpb32_raw->fatSize32);
		partBpb->activeFat = getI16(bpb32_raw->fatStatus);
		if (partBpb->activeFat & 0x80) { //fat not synced
			partBpb->activeFat = (partBpb->activeFat & 0xF);
		} else {
			partBpb->activeFat = 0;
		}
		partBpb->rootDirStart = partBpb->partStart + (partBpb->fatCount * partBpb->fatSize) + partBpb->resSectors;
		partBpb->rootDirCluster = getI32(bpb32_raw->rootDirCluster);
		for (ret = 0; ret < 8; ret++) {
			partBpb->fatId[ret] = bpb32_raw->fatId[ret];
		}
		partBpb->fatId[ret] = 0;
		partBpb->dataStart = partBpb->rootDirStart;
	}

	printf("USBHDFSD: Fat type %u Id %s \n", partBpb->fatType, partBpb->fatId);
	return 1;
}

//---------------------------------------------------------------------------
/*
 returns:
 0 - no more dir entries
 1 - short name dir entry found
 2 - long name dir entry found
 3 - deleted dir entry found
*/
int fat_getDirentry(unsigned char fatType, fat_direntry* dir_entry, fat_direntry_summary* dir ) {
	int i, j;
	unsigned int offset;
	unsigned char cont;
	u16 character;

	//detect last entry - all zeros (slight modification by radad)
	if (dir_entry->sfn.name[0] == 0) {
		return 0;
	}
	//detect deleted entry - it will be ignored
	if (dir_entry->sfn.name[0] == 0xE5) {
		return 3;
	}

	//detect long filename
	if (dir_entry->lfn.rshv == 0x0F && dir_entry->lfn.reserved1 == 0x00 && dir_entry->lfn.reserved2[0] == 0x00) {
		//long filename - almost whole direntry is unicode string - extract it
		offset = dir_entry->lfn.entrySeq & 0x3f;
		offset--;
		offset = offset * 13;
		//name - 1st part
		cont = 1;
		for (i = 0; i < 10 && cont; i+=2) {
			character = dir_entry->lfn.name1[i] | (dir_entry->lfn.name1[i+1] << 8);

			if (character == 0 || offset >= FAT_MAX_NAME) {
				dir->name[offset] = 0; //terminate
				cont = 0; //stop
			} else {
				// Handle non-ASCII characters
				dir->name[offset] = character < 128 ? dir_entry->lfn.name1[i] : '?';
				offset++;
			}
		}
		//name - 2nd part
		for (i = 0; i < 12 && cont; i+=2) {
			character = dir_entry->lfn.name2[i] | (dir_entry->lfn.name2[i+1] << 8);

			if (character == 0 || offset >= FAT_MAX_NAME) {
				dir->name[offset] = 0; //terminate
				cont = 0; //stop
			} else {
				// Handle non-ASCII characters
				dir->name[offset] = character < 128 ? dir_entry->lfn.name2[i] : '?';
				offset++;
			}
		}
		//name - 3rd part
		for (i = 0; i < 4 && cont; i+=2) {
			character = dir_entry->lfn.name3[i] | (dir_entry->lfn.name3[i+1] << 8);

			if (character == 0 || offset >= FAT_MAX_NAME) {
				dir->name[offset] = 0; //terminate
				cont = 0; //stop
			} else {
				// Handle non-ASCII characters
				dir->name[offset] = character < 128 ? dir_entry->lfn.name3[i] : '?';
				offset++;
			}
		}
		if ((dir_entry->lfn.entrySeq & 0x40)) { //terminate string flag
			dir->name[offset] = 0;
		}
		return 2;
	} else {
		//short filename
		//copy name
		for (i = 0; i < 8 && dir_entry->sfn.name[i]!= ' '; i++) {
			dir->sname[i] = dir_entry->sfn.name[i];
			// NT—adaption for LaunchELF
			if (dir_entry->sfn.reservedNT & 0x08 &&
			  dir->sname[i] >= 'A' && dir->sname[i] <= 'Z') {
				dir->sname[i] += 0x20;	//Force standard letters in name to lower case
			}
		}
		for (j=0; j < 3 && dir_entry->sfn.ext[j] != ' '; j++) {
			if (j == 0) {
				dir->sname[i] = '.';
				i++;
			}
			dir->sname[i+j] = dir_entry->sfn.ext[j];
			// NT—adaption for LaunchELF
			if (dir_entry->sfn.reservedNT & 0x10 &&
			  dir->sname[i+j] >= 'A' && dir->sname[i+j] <= 'Z') {
				dir->sname[i+j] += 0x20;	//Force standard letters in ext to lower case
			}
		}
		dir->sname[i+j] = 0; //terminate
		if (dir->name[0] == 0) { //long name desn't exit
			for (i =0 ; dir->sname[i] !=0; i++) dir->name[i] = dir->sname[i];
			dir->name[i] = 0;
		}
		dir->attr = dir_entry->sfn.attr;
		dir->size = getI32(dir_entry->sfn.size);
		dir->cluster = (fatType == FAT32) ? getI32_2(dir_entry->sfn.clusterL, dir_entry->sfn.clusterH) : getI16(dir_entry->sfn.clusterL);

		return 1;
	}
}

//---------------------------------------------------------------------------
//Set chain info (cluster/offset) cache
void fat_setFatDirChain(fat_driver* fatd, fat_dir* fatDir) {
	int i,j;
	unsigned int index, clusterChainStart, fileCluster, fileSize, blockSize;
	unsigned char nextChain;
	int chainSize;

	XPRINTF("USBHDFSD: reading cluster chain  \n");
	fileCluster = fatDir->chain[0].cluster;

	if (fileCluster < 2) {
		XPRINTF("USBHDFSD:    early exit... \n");
		return;
	}

	fileSize = fatDir->size;
	blockSize = fileSize / DIR_CHAIN_SIZE;

	nextChain = 1;
	clusterChainStart = 0;
	j = 1;
	fileSize = 0;
	index = 0;

	while (nextChain) {
		if((chainSize = fat_getClusterChain(fatd, fileCluster, fatd->cbuf, MAX_DIR_CLUSTER, 1)) >=0){
			if (chainSize >= MAX_DIR_CLUSTER) { //the chain is full, but more chain parts exist
				fileCluster = fatd->cbuf[MAX_DIR_CLUSTER - 1];
			}else { //chain fits in the chain buffer completely - no next chain exist
				nextChain = 0;
			}
		}else{
			XPRINTF("USBHDFSD: fat_setFatDirChain(): fat_getClusterChain() failed: %d\n", chainSize);
			return;
		}

		//process the cluster chain (fatd->cbuf)
		for (i = clusterChainStart; i < chainSize; i++) {
			fileSize += (fatd->partBpb.clusterSize * fatd->partBpb.sectorSize);
			while (fileSize >= (j * blockSize) && j < DIR_CHAIN_SIZE) {
				fatDir->chain[j].cluster = fatd->cbuf[i];
				fatDir->chain[j].index = index;
				j++;
			}//ends "while"
			index++;
		}//ends "for"
		clusterChainStart = 1;
	}//ends "while"
	fatDir->lastCluster = fatd->cbuf[i-1];

#ifdef DEBUG_EXTREME //dlanor: I patched this because this bloat hid important stuff
	//debug
	XPRINTF("USBHDFSD: SEEK CLUSTER CHAIN CACHE fileSize=%u blockSize=%u \n", fatDir->size, blockSize);
	for (i = 0; i < DIR_CHAIN_SIZE; i++) {
		XPRINTF("USBHDFSD: index=%u cluster=%u offset= %u - %u start=%u \n",
			fatDir->chain[i].index, fatDir->chain[i].cluster,
			fatDir->chain[i].index * fatd->partBpb.clusterSize * fatd->partBpb.sectorSize,
			(fatDir->chain[i].index+1) * fatd->partBpb.clusterSize * fatd->partBpb.sectorSize,
			i * blockSize);
	}
#endif /* debug */
	XPRINTF("USBHDFSD: read cluster chain  done!\n");
}

//---------------------------------------------------------------------------
/* Set base attributes of direntry */
static void fat_setFatDir(fat_driver* fatd, fat_dir* fatDir, unsigned int parentDirCluster, fat_direntry_sfn* dsfn, fat_direntry_summary* dir, int getClusterInfo ) {
	unsigned int i;
	unsigned char* srcName;

	XPRINTF("USBHDFSD: setting fat dir...\n");
	srcName = dir->sname;
	if (dir->name[0] != 0) { //long filename not empty
		srcName = dir->name;
	}
	//copy name
	for (i = 0; srcName[i] != 0; i++) fatDir->name[i] = srcName[i];
	fatDir->name[i] = 0; //terminate

	fatDir->attr = dir->attr;
	fatDir->size = dir->size;

	//created Date: Day, Month, Year-low, Year-high
	fatDir->cdate[0] = (dsfn->dateCreate[0] & 0x1F);
	fatDir->cdate[1] = (dsfn->dateCreate[0] >> 5) + ((dsfn->dateCreate[1] & 0x01) << 3 );
	i = 1980 + (dsfn->dateCreate[1] >> 1);
	fatDir->cdate[2] = (i & 0xFF);
	fatDir->cdate[3] = ((i & 0xFF00)>> 8);

	//created Time: Hours, Minutes, Seconds
	fatDir->ctime[0] = ((dsfn->timeCreate[1] & 0xF8) >> 3);
	fatDir->ctime[1] = ((dsfn->timeCreate[1] & 0x07) << 3) + ((dsfn->timeCreate[0] & 0xE0) >> 5);
	fatDir->ctime[6] = ((dsfn->timeCreate[0] & 0x1F) << 1);

	//accessed Date: Day, Month, Year-low, Year-high
	fatDir->adate[0] = (dsfn->dateAccess[0] & 0x1F);
	fatDir->adate[1] = (dsfn->dateAccess[0] >> 5) + ((dsfn->dateAccess[1] & 0x01) << 3 );
	i = 1980 + (dsfn->dateAccess[1] >> 1);
	fatDir->adate[2] = (i & 0xFF);
	fatDir->adate[3] = ((i & 0xFF00)>> 8);

	//modified Date: Day, Month, Year-low, Year-high
	fatDir->mdate[0] = (dsfn->dateWrite[0] & 0x1F);
	fatDir->mdate[1] = (dsfn->dateWrite[0] >> 5) + ((dsfn->dateWrite[1] & 0x01) << 3 );
	i = 1980 + (dsfn->dateWrite[1] >> 1);
	fatDir->mdate[2] = (i & 0xFF);
	fatDir->mdate[3] = ((i & 0xFF00)>> 8);

	//modified Time: Hours, Minutes, Seconds
	fatDir->mtime[0] = ((dsfn->timeWrite[1] & 0xF8) >> 3);
	fatDir->mtime[1] = ((dsfn->timeWrite[1] & 0x07) << 3) + ((dsfn->timeWrite[0] & 0xE0) >> 5);
	fatDir->mtime[2] = ((dsfn->timeWrite[0] & 0x1F) << 1);

	fatDir->chain[0].cluster = dir->cluster;
	fatDir->chain[0].index  = 0;
	if (getClusterInfo) {
		fat_setFatDirChain(fatd, fatDir);
	}

	fatDir->parentDirCluster = parentDirCluster;
	fatDir->startCluster = dir->cluster;
}

//---------------------------------------------------------------------------
int fat_getDirentrySectorData(fat_driver* fatd, unsigned int* startCluster, unsigned int* startSector, unsigned int* dirSector) {
	unsigned int chainSize;

	if (*startCluster == 0 && fatd->partBpb.fatType < FAT32) { //Root directory
		*startSector = fatd->partBpb.rootDirStart;
		*dirSector =  fatd->partBpb.rootSize / (fatd->partBpb.sectorSize / 32);
		return 0;
	}
	 //other directory or fat 32
	if (*startCluster == 0 && fatd->partBpb.fatType == FAT32) {
		*startCluster = fatd->partBpb.rootDirCluster;
	}
	*startSector = fat_cluster2sector(&fatd->partBpb, *startCluster);
	chainSize = fat_getClusterChain(fatd, *startCluster, fatd->cbuf, MAX_DIR_CLUSTER, 1);
	if (chainSize >= MAX_DIR_CLUSTER) {
		XPRINTF("USBHDFSD: Chain too large\n");
		return -EFAULT;
	} else if (chainSize > 0) {
		*dirSector = chainSize * fatd->partBpb.clusterSize;
	} else {
		XPRINTF("USBHDFSD: Error getting cluster chain! startCluster=%u \n", *startCluster);
		return -EFAULT;
	}

	return chainSize;
}

//---------------------------------------------------------------------------
static int fat_getDirentryStartCluster(fat_driver* fatd, unsigned char* dirName, unsigned int* startCluster, fat_dir* fatDir) {
	fat_direntry_summary dir;
	unsigned int i, dirSector, startSector, dirPos;
	unsigned char cont;
	int ret;
#ifdef DEBUG
	mass_dev* mass_device = fatd->dev;
#endif

	cont = 1;
	XPRINTF("USBHDFSD: getting cluster for dir entry: %s \n", dirName);
	//clear name strings
	dir.sname[0] = 0;
	dir.name[0] = 0;

	ret = fat_getDirentrySectorData(fatd, startCluster, &startSector, &dirSector);
	if (ret < 0)
		return ret;

	XPRINTF("USBHDFSD: dirCluster=%u startSector=%u (%u) dirSector=%u \n", *startCluster, startSector, startSector * mass_device->sectorSize, dirSector);

	//go through first directory sector till the max number of directory sectors
	//or stop when no more direntries detected
	for (i = 0; i < dirSector && cont; i++) {
		unsigned char* sbuf = NULL; //sector buffer

		//At cluster borders, get correct sector from cluster chain buffer
		if ((*startCluster != 0) && (i % fatd->partBpb.clusterSize == 0)) {
			startSector = fat_cluster2sector(&fatd->partBpb, fatd->cbuf[(i / fatd->partBpb.clusterSize)]) -i;
		}

		ret = READ_SECTOR(fatd->dev, startSector + i, sbuf);
		if (ret < 0) {
			XPRINTF("USBHDFSD: read directory sector failed ! sector=%u\n", startSector + i);
			return -EIO;
		}
		XPRINTF("USBHDFSD: read sector ok, scanning sector for direntries...\n");
		dirPos = 0;

		// go through start of the sector till the end of sector
		while (cont &&  dirPos < fatd->partBpb.sectorSize) {
			fat_direntry* dir_entry = (fat_direntry*) (sbuf + dirPos);
			cont = fat_getDirentry(fatd->partBpb.fatType, dir_entry, &dir); //get single directory entry from sector buffer
			if (cont == 1) { //when short file name entry detected
				if (!(dir.attr & FAT_ATTR_VOLUME_LABEL)) { //not volume label
					if ((strEqual(dir.sname, dirName) == 0) ||
						(strEqual(dir.name, dirName) == 0) ) {
							XPRINTF("USBHDFSD: found! %s\n", dir.name);
							if (fatDir != NULL) { //fill the directory properties
								fat_setFatDir(fatd, fatDir, *startCluster, &dir_entry->sfn, &dir, 1);
							}
							*startCluster = dir.cluster;
							XPRINTF("USBHDFSD: direntry %s found at cluster: %u \n", dirName, dir.cluster);
							return dir.attr; //returns file or directory attr
						}
				}//ends "if(!(dir.attr & FAT_ATTR_VOLUME_LABEL))"
				//clear name strings
				dir.sname[0] = 0;
				dir.name[0] = 0;
			}//ends "if (cont == 1)"
			dirPos += sizeof(fat_direntry);
		}//ends "while"
	}//ends "for"
	XPRINTF("USBHDFSD: direntry %s not found! \n", dirName);
	return -ENOENT;
}

//---------------------------------------------------------------------------
// start cluster should be 0 - if we want to search from root directory
// otherwise the start cluster should be correct cluster of directory
// to search directory - set fatDir as NULL
int fat_getFileStartCluster(fat_driver* fatd, const unsigned char* fname, unsigned int* startCluster, fat_dir* fatDir) {
	unsigned char tmpName[FAT_MAX_NAME+1];
	unsigned int i, offset;
	unsigned char cont;
	int ret;

	XPRINTF("USBHDFSD: Entering fat_getFileStartCluster\n");

	cont = 1;
	offset = 0;
	i=0;

	*startCluster = 0;
	if (fatDir != NULL) {
		memset(fatDir, 0, sizeof(fat_dir));
		fatDir->attr = FAT_ATTR_DIRECTORY;
	}
	if (fname[i] == '/') {
		i++;
	}

	for ( ; fname[i] !=0; i++) {
		if (fname[i] == '/') { //directory separator
			tmpName[offset] = 0; //terminate string
			ret = fat_getDirentryStartCluster(fatd, tmpName, startCluster, fatDir);
			if (ret < 0) {
				return -ENOENT;
			}
			offset = 0;
		} else{
			tmpName[offset] = fname[i];
			offset++;
		}
	}//ends "for"
	//and the final file
	tmpName[offset] = 0; //terminate string
	XPRINTF("USBHDFSD: Ready to get cluster for file \"%s\"\n", tmpName);
	if (fatDir != NULL) {
		//if the last char of the name was slash - the name was already found -exit
		if (offset == 0) {
			XPRINTF("USBHDFSD: Exiting from fat_getFileStartCluster with a folder\n");
			return 2;
		}
		ret = fat_getDirentryStartCluster(fatd, tmpName, startCluster, fatDir);
		if (ret < 0) {
			XPRINTF("USBHDFSD: Exiting from fat_getFileStartCluster with error %i\n", ret);
			return ret;
		}
		XPRINTF("USBHDFSD: file's startCluster found. Name=%s, cluster=%u \n", fname, *startCluster);
	}
	XPRINTF("USBHDFSD: Exiting from fat_getFileStartCluster with no error.\n");
	return 1;
}

//---------------------------------------------------------------------------
void fat_getClusterAtFilePos(fat_driver* fatd, fat_dir* fatDir, unsigned int filePos, unsigned int* cluster, unsigned int* clusterPos) {
	unsigned int i, j, blockSize;

	blockSize = fatd->partBpb.clusterSize * fatd->partBpb.sectorSize;

	for (i = 0, j = (DIR_CHAIN_SIZE-1); i < (DIR_CHAIN_SIZE-1); i++) {
		if (fatDir->chain[i].index   * blockSize <= filePos &&
			fatDir->chain[i+1].index * blockSize >  filePos) {
				j = i;
				break;
			}
	}
	*cluster    = fatDir->chain[j].cluster;
	*clusterPos = (fatDir->chain[j].index * blockSize);
}

//---------------------------------------------------------------------------
int fat_readFile(fat_driver* fatd, fat_dir* fatDir, unsigned int filePos, unsigned char* buffer, unsigned int size) {
	int ret, chainSize;
	unsigned int i, j, startSector, clusterChainStart, bufSize, sectorSkip, clusterSkip, dataSkip;
	unsigned char nextChain;
	mass_dev* mass_device = fatd->dev;

	unsigned int bufferPos, fileCluster, clusterPos;

	fat_getClusterAtFilePos(fatd, fatDir, filePos, &fileCluster, &clusterPos);
	sectorSkip = (filePos - clusterPos) / fatd->partBpb.sectorSize;
	clusterSkip = sectorSkip / fatd->partBpb.clusterSize;
	sectorSkip %= fatd->partBpb.clusterSize;
	dataSkip  = filePos  % fatd->partBpb.sectorSize;
	bufferPos = 0;

	XPRINTF("USBHDFSD: fileCluster = %u,  clusterPos= %u clusterSkip=%u, sectorSkip=%u dataSkip=%u \n",
		fileCluster, clusterPos, clusterSkip, sectorSkip, dataSkip);

	if (fileCluster < 2) {
		return 0;
	}

	bufSize = mass_device->sectorSize;
	nextChain = 1;
	clusterChainStart = 1;

	while (nextChain && size > 0 ) {
		if((chainSize = fat_getClusterChain(fatd, fileCluster, fatd->cbuf, MAX_DIR_CLUSTER, clusterChainStart))<0){
			return chainSize;
		}

		clusterChainStart = 0;
		if (chainSize >= MAX_DIR_CLUSTER) { //the chain is full, but more chain parts exist
			fileCluster = fatd->cbuf[MAX_DIR_CLUSTER - 1];
		}else { //chain fits in the chain buffer completely - no next chain needed
			nextChain = 0;
		}
		while (clusterSkip >= MAX_DIR_CLUSTER) {
			chainSize = fat_getClusterChain(fatd, fileCluster, fatd->cbuf, MAX_DIR_CLUSTER, clusterChainStart);
			clusterChainStart = 0;
			if (chainSize >= MAX_DIR_CLUSTER) { //the chain is full, but more chain parts exist
				fileCluster = fatd->cbuf[MAX_DIR_CLUSTER - 1];
			}else { //chain fits in the chain buffer completely - no next chain needed
				nextChain = 0;
			}
			clusterSkip -= MAX_DIR_CLUSTER;
		}

		//process the cluster chain (fatd->cbuf) and skip leading clusters if needed
		for (i = 0 + clusterSkip; i < chainSize && size > 0; i++) {
			//read cluster and save cluster content
			startSector = fat_cluster2sector(&fatd->partBpb, fatd->cbuf[i]);
			//process all sectors of the cluster (and skip leading sectors if needed)
			for (j = 0 + sectorSkip; j < fatd->partBpb.clusterSize && size > 0; j++) {
				unsigned char* sbuf = NULL; //sector buffer

				ret = READ_SECTOR(fatd->dev, startSector + j, sbuf);
				if (ret < 0) {
					XPRINTF("USBHDFSD: Read sector failed ! sector=%u\n", startSector + j);
					return bufferPos;
				}

				//compute exact size of transfered bytes
				if (size < bufSize) {
					bufSize = size + dataSkip;
				}
				if (bufSize > mass_device->sectorSize) {
					bufSize = mass_device->sectorSize;
				}
				XPRINTF("USBHDFSD: memcopy dst=%u, src=%u, size=%u  bufSize=%u \n", bufferPos, dataSkip, bufSize-dataSkip, bufSize);
				memcpy(buffer+bufferPos, sbuf + dataSkip, bufSize - dataSkip);
				size-= (bufSize - dataSkip);
				bufferPos +=  (bufSize - dataSkip);
				dataSkip = 0;
				bufSize = mass_device->sectorSize;
			}
			sectorSkip = 0;
		}
		clusterSkip = 0;
	}
	return bufferPos;
}

//---------------------------------------------------------------------------
int fat_getNextDirentry(fat_driver* fatd, fat_dir_list* fatdlist, fat_dir* fatDir) {
	fat_direntry_summary dir;
	int i, ret;
	unsigned int startSector, dirSector, dirPos, dirCluster;
	unsigned char cont, new_entry;
#ifdef DEBUG
	mass_dev* mass_device = fatd->dev;
#endif

	//the getFirst function was not called
	if (fatdlist->direntryCluster == 0xFFFFFFFF || fatDir == NULL) {
		return -EFAULT;
	}

	dirCluster = fatdlist->direntryCluster;

	//clear name strings
	dir.sname[0] = 0;
	dir.name[0] = 0;

	ret = fat_getDirentrySectorData(fatd, &dirCluster, &startSector, &dirSector);
	if (ret < 0)
		return ret;

	XPRINTF("USBHDFSD: dirCluster=%u startSector=%u (%u) dirSector=%u \n", dirCluster, startSector, startSector * mass_device->sectorSize, dirSector);

	//go through first directory sector till the max number of directory sectors
	//or stop when no more direntries detected
	//dlanor: but avoid rescanning same areas redundantly (if possible)
	cont = 1;
	new_entry = 1;
	dirPos = (fatdlist->direntryIndex*32) % fatd->partBpb.sectorSize;
	for (i = ((fatdlist->direntryIndex*32) / fatd->partBpb.sectorSize); (i < dirSector) && cont; i++) {
		unsigned char* sbuf = NULL; //sector buffer

		//At cluster borders, get correct sector from cluster chain buffer
		if ((dirCluster != 0) && (new_entry || (i % fatd->partBpb.clusterSize == 0))) {
			startSector = fat_cluster2sector(&fatd->partBpb, fatd->cbuf[(i / fatd->partBpb.clusterSize)])
				-i + (i % fatd->partBpb.clusterSize);
			new_entry = 0;
		}
		ret = READ_SECTOR(fatd->dev, startSector + i, sbuf);
		if (ret < 0) {
			XPRINTF("USBHDFSD: Read directory  sector failed ! sector=%u\n", startSector + i);
			return -EIO;
		}

		// go through sector from current pos till its end
		while (cont &&  (dirPos < fatd->partBpb.sectorSize)) {
			fat_direntry* dir_entry = (fat_direntry*) (sbuf + dirPos);
			cont = fat_getDirentry(fatd->partBpb.fatType, dir_entry, &dir); //get a directory entry from sector
			fatdlist->direntryIndex++; //Note current entry processed
			if (cont == 1) { //when short file name entry detected
				fat_setFatDir(fatd, fatDir, dirCluster, &dir_entry->sfn, &dir, 0);
#if 0
			XPRINTF("USBHDFSD: fat_getNextDirentry %c%c%c%c%c%c %x %s %s\n",
				(dir.attr & FAT_ATTR_VOLUME_LABEL) ? 'v' : '-',
				(dir.attr & FAT_ATTR_DIRECTORY) ? 'd' : '-',
				(dir.attr & FAT_ATTR_READONLY) ? 'r' : '-',
				(dir.attr & FAT_ATTR_ARCHIVE) ? 'a' : '-',
				(dir.attr & FAT_ATTR_SYSTEM) ? 's' : '-',
				(dir.attr & FAT_ATTR_HIDDEN) ? 'h' : '-',
				dir.attr,
				dir.sname,
				dir.name);
#endif
				return 1;
			}
			dirPos += sizeof(fat_direntry);
		}//ends "while"
		dirPos = 0;
	}//ends "for"
	// when we get this far - reset the direntry cluster
	fatdlist->direntryCluster = 0xFFFFFFFF; //no more files
	return 0; //indicate that no direntry is avalable
}

//---------------------------------------------------------------------------
int fat_getFirstDirentry(fat_driver* fatd, const unsigned char* dirName, fat_dir_list* fatdlist, fat_dir *fatDir_host, fat_dir* fatDir) {
	int ret;
	unsigned int startCluster = 0;

	ret = fat_getFileStartCluster(fatd, dirName, &startCluster, fatDir_host);
	if (ret < 0) { //dir name not found
		return -ENOENT;
	}
	//check that direntry is directory
	if (!(fatDir_host->attr & FAT_ATTR_DIRECTORY)) {
		return -ENOTDIR; //it's a file - exit
	}
	fatdlist->direntryCluster = startCluster;
	fatdlist->direntryIndex = 0;
	return fat_getNextDirentry(fatd, fatdlist, fatDir);
}

//---------------------------------------------------------------------------
int fat_CheckChain(fat_driver* fatd, fat_dir* fatDir){
	int i;
	int chainSize;
	int nextChain;

	unsigned int fileCluster;
	unsigned int clusterPos;

	int clusterChainStart;

	fat_getClusterAtFilePos(fatd, fatDir, 0, &fileCluster, &clusterPos);

	if (fileCluster < 2) return 1;

	nextChain = 1;
	clusterChainStart = 1;

	while (nextChain) {
		chainSize = fat_getClusterChain(fatd, fileCluster, fatd->cbuf, MAX_DIR_CLUSTER, clusterChainStart);
		clusterChainStart = 0;
		if (chainSize >= MAX_DIR_CLUSTER) { //the chain is full, but more chain parts exist
			fileCluster = fatd->cbuf[MAX_DIR_CLUSTER - 1];
		}else { //chain fits in the chain buffer completely - no next chain needed
			nextChain = 0;
		}

		//process the cluster chain (fatd->cbuf) and skip leading clusters if needed
		for (i = 0; i < (chainSize-1); i++) {
			if((fatd->cbuf[i]+1)!=fatd->cbuf[i+1]) return 0;
		}
	}

	return 1;
}

//---------------------------------------------------------------------------
int fat_mount(mass_dev* dev, unsigned int start, unsigned int count)
{
	fat_driver* fatd = NULL;
	unsigned int i;
	for (i = 0; i < NUM_DRIVES && fatd == NULL; ++i)
	{
		if (g_fatd[i] == NULL)
		{
			XPRINTF("USBHDFSD: usb fat: allocate fat_driver %d!\n", sizeof(fat_driver));
			g_fatd[i] = malloc(sizeof(fat_driver));
			if (g_fatd[i] != NULL)
			{
				g_fatd[i]->dev = NULL;
			}
			fatd = g_fatd[i];
		}
		else if(g_fatd[i]->dev == NULL)
		{
			fatd = g_fatd[i];
		}
	}

	if (fatd == NULL)
	{
		printf("USBHDFSD: usb fat: unable to allocate drive!\n");
		return -1;
	}

	if (fatd->dev != NULL)
	{
		printf("USBHDFSD: usb fat: mount ERROR: alread mounted\n");
		fat_forceUnmount(fatd->dev);
	}

	if (fat_getPartitionBootSector(dev, start, &fatd->partBpb) < 0)
		return -1;

	fatd->dev = dev;
	fatd->deIdx = 0;
	fatd->clStackIndex = 0;
	fatd->clStackLast = 0;
	fatd->lastChainCluster = 0xFFFFFFFF;
	fatd->lastChainResult = -1;
	return 0;
}

//---------------------------------------------------------------------------
void fat_forceUnmount(mass_dev* dev)
{
	unsigned int i;
	XPRINTF("USBHDFSD: usb fat: forceUnmount devId %i \n", dev->devId);

	for (i = 0; i < NUM_DRIVES; ++i)
	{
		if (g_fatd[i] != NULL && g_fatd[i]->dev == dev)
			g_fatd[i] = NULL;
	}
}

//---------------------------------------------------------------------------
fat_driver * fat_getData(int device)
{
	if (device >= NUM_DRIVES)
		return NULL;

	while (g_fatd[device] == NULL || g_fatd[device]->dev == NULL)
	{
		if (mass_stor_configureNextDevice() <= 0)
			break;
	}

	if (g_fatd[device] == NULL || g_fatd[device]->dev == NULL)
		return NULL;
	else
		return g_fatd[device];
}

//---------------------------------------------------------------------------
//End of file:  fat_driver.c
//---------------------------------------------------------------------------