407 lines
10 KiB
C
407 lines
10 KiB
C
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#include "imagpart.h"
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//
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// FAT boot sector.
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//
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#pragma pack(1)
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typedef struct FAT_BOOT_SECTOR {
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BYTE Jump[3]; // offset = 0x00 0
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UCHAR Oem[8]; // offset = 0x03 3
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USHORT BytesPerSector; // offset = 0x0b 11
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BYTE SectorsPerCluster; // offset = 0x0d 13
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USHORT ReservedSectors; // offset = 0x0e 14
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BYTE Fats; // offset = 0x10 16
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USHORT RootEntries; // offset = 0x11 17
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USHORT Sectors; // offset = 0x13 19
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BYTE Media; // offset = 0x15 21
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USHORT SectorsPerFat; // offset = 0x16 22
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USHORT SectorsPerTrack; // offset = 0x18 24
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USHORT Heads; // offset = 0x1a 26
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ULONG HiddenSectors; // offset = 0x1c 28
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ULONG LargeSectors; // offset = 0x20 32
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BYTE PhysicalDriveNumber; // offset = 0x24 36
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BYTE Reserved; // offset = 0x25 37
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BYTE Signature; // offset = 0x26 38
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ULONG Id; // offset = 0x27 39
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UCHAR VolumeLabel[11]; // offset = 0x2B 43
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UCHAR SystemId[8]; // offset = 0x36 54
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BYTE BootStrap[510-62]; // offset = 0x3e 62
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BYTE AA55Signature[2]; // offset = 0x1fe 510
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} FAT_BOOT_SECTOR,_far *FPFAT_BOOT_SECTOR;
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#pragma pack()
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typedef enum {
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Fat12,
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Fat16,
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Fat32
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} FatSize;
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FatSize
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pFatDetermineFatSize(
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IN FPFAT_BOOT_SECTOR BootSector
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);
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ULONG
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pFatClusterCount(
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IN FPFAT_BOOT_SECTOR BootSector
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);
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ULONG
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pFatFirstClusterSector(
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IN FPFAT_BOOT_SECTOR BootSector
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);
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ULONG
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pFatSectorsPerFat(
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IN FPFAT_BOOT_SECTOR BootSector
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);
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BOOL
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FatIsFat(
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IN HPARTITION PartitionHandle
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)
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{
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FPFAT_BOOT_SECTOR BootSector;
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if(!ReadPartition(PartitionHandle,0,1,IoBuffer)) {
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return(FALSE);
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}
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BootSector = IoBuffer;
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if(BootSector->Sectors) {
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BootSector->LargeSectors = 0;
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}
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//
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// Check various fields for permissible values.
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//
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if((BootSector->Jump[0] != 0x49) // Fujitsu FMR
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&& (BootSector->Jump[0] != 0xe9)
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&& (BootSector->Jump[0] != 0xeb)) {
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return(FALSE);
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}
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if(BootSector->BytesPerSector != 512) {
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return(FALSE);
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}
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if((BootSector->SectorsPerCluster != 1)
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&& (BootSector->SectorsPerCluster != 2)
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&& (BootSector->SectorsPerCluster != 4)
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&& (BootSector->SectorsPerCluster != 8)
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&& (BootSector->SectorsPerCluster != 16)
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&& (BootSector->SectorsPerCluster != 32)
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&& (BootSector->SectorsPerCluster != 64)
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&& (BootSector->SectorsPerCluster != 128)) {
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return(FALSE);
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}
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if(!BootSector->ReservedSectors || !BootSector->Fats) {
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return(FALSE);
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}
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if(!BootSector->Sectors && !BootSector->LargeSectors) {
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return(FALSE);
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}
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if((BootSector->Media != 0x00) // FMR (formatted by OS/2)
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&& (BootSector->Media != 0x01) // FMR (floppy, formatted by DOS)
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&& (BootSector->Media != 0xf0)
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&& (BootSector->Media != 0xf8)
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&& (BootSector->Media != 0xf9)
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&& (BootSector->Media != 0xfa) // FMR
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&& (BootSector->Media != 0xfb)
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&& (BootSector->Media != 0xfc)
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&& (BootSector->Media != 0xfd)
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&& (BootSector->Media != 0xfe)
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&& (BootSector->Media != 0xff)) {
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return(FALSE);
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}
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if(BootSector->SectorsPerFat && !BootSector->RootEntries) {
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return(FALSE);
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}
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return(TRUE);
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}
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BOOL
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FatInitializeVolumeData(
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IN HPARTITION PartitionHandle,
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OUT ULONG *TotalSectorCount,
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OUT ULONG *NonClusterSectors,
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OUT ULONG *ClusterCount,
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OUT BYTE *SectorsPerCluster
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)
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{
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FPFAT_BOOT_SECTOR BootSector;
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if(!ReadPartition(PartitionHandle,0,1,IoBuffer)) {
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fprintf(stderr,"\n");
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fprintf(stderr,textReadFailedAtSector,0L);
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fprintf(stderr,"\n");
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return(FALSE);
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}
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BootSector = IoBuffer;
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*TotalSectorCount = BootSector->Sectors
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? (ULONG)BootSector->Sectors
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: BootSector->LargeSectors;
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*ClusterCount = pFatClusterCount(BootSector);
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*NonClusterSectors = pFatFirstClusterSector(BootSector);
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*SectorsPerCluster = BootSector->SectorsPerCluster;
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return(TRUE);
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}
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BOOL
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FatBuildClusterBitmap(
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IN HPARTITION PartitionHandle,
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IN UINT FileHandle,
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IN OUT PARTITION_IMAGE *PartitionImage
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)
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{
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FPFAT_BOOT_SECTOR BootSector;
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FatSize fatsize;
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ULONG CurrentFatSectorBase;
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ULONG FatSectorsLeft;
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ULONG CurrentCluster;
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ULONG SectorsPerFat;
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BYTE c;
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USHORT ClusterLimit;
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USHORT i;
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USHORT x1;
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ULONG x2;
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printf(textScanningFat,0L);
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printf("\r");
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if(!ReadPartition(PartitionHandle,0,1,IoBuffer)) {
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fprintf(stderr,"\n");
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fprintf(stderr,textReadFailedAtSector,0L);
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fprintf(stderr,"\n");
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return(FALSE);
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}
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BootSector = IoBuffer;
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fatsize = pFatDetermineFatSize(BootSector);
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CurrentFatSectorBase = BootSector->ReservedSectors;
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SectorsPerFat = pFatSectorsPerFat(BootSector);
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FatSectorsLeft = SectorsPerFat;
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CurrentCluster = 0;
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InitClusterBuffer((FPBYTE)IoBuffer + (3*512),FileHandle);
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while(CurrentCluster < PartitionImage->ClusterCount) {
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//
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// Read next block of fat sectors. Deal with 3 at a time so
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// we never get partial 12-bit fat entries.
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//
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c = 3;
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if((ULONG)c > FatSectorsLeft) {
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c = (BYTE)FatSectorsLeft;
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}
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if(!ReadPartition(PartitionHandle,CurrentFatSectorBase,c,IoBuffer)) {
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fprintf(stderr,"\n");
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fprintf(stderr,textReadFailedAtSector,CurrentFatSectorBase);
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fprintf(stderr,"\n");
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return(FALSE);
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}
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//
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// Figure out how many clusters are described by the 3 sectors
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// of the FAT we just read in
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//
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switch(fatsize) {
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case Fat12:
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ClusterLimit = 1024;
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break;
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case Fat16:
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ClusterLimit = 768;
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break;
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case Fat32:
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ClusterLimit = 384;
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break;
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}
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if((CurrentCluster + ClusterLimit) > PartitionImage->ClusterCount) {
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ClusterLimit = (USHORT)(PartitionImage->ClusterCount - CurrentCluster);
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}
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//
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// Fat values:
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//
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// 0 - free cluster
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// 1 - (unused)
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// [ffff]ff0 - [ffff]ff6 - (reserved)
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// [ffff]ff7 - bad cluster
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// [ffff]ff8 - [ffff]fff - last cluster of file
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//
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// All other values - used cluster
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//
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switch(fatsize) {
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case Fat12:
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for(i=0; i<ClusterLimit; i++,CurrentCluster++) {
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x1 = *(FPUSHORT)((FPBYTE)IoBuffer + (3 * i / 2));
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if(i & 1) {
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x1 >>= 4;
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} else {
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x1 &= 0xfffU;
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}
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if((((x1 > 1) && (x1 <= 0xfefU)) || (x1 >= 0xff8U)) && (CurrentCluster >= 2)) {
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PartitionImage->LastUsedCluster = CurrentCluster-2;
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PartitionImage->UsedClusterCount++;
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if(!MarkClusterUsed(CurrentCluster-2)) {
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return(FALSE);
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}
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}
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}
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break;
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case Fat16:
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for(i=0; i<ClusterLimit; i++,CurrentCluster++) {
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x1 = ((FPUSHORT)IoBuffer)[i];
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if((((x1 > 1) && (x1 <= 0xffefU)) || (x1 >= 0xfff8U)) && (CurrentCluster >= 2)) {
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PartitionImage->LastUsedCluster = CurrentCluster-2;
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PartitionImage->UsedClusterCount++;
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if(!MarkClusterUsed(CurrentCluster-2)) {
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return(FALSE);
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}
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}
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}
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break;
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case Fat32:
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for(i=0; i<ClusterLimit; i++,CurrentCluster++) {
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x2 = ((FPULONG)IoBuffer)[i] & 0xfffffffU;
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if((((x2 > 1) && (x2 <= 0xfffffefUL)) || (x2 >= 0xffffff8UL)) && (CurrentCluster >= 2)) {
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PartitionImage->LastUsedCluster = CurrentCluster-2;
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PartitionImage->UsedClusterCount++;
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if(!MarkClusterUsed(CurrentCluster-2)) {
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return(FALSE);
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}
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}
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}
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break;
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}
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CurrentFatSectorBase += c;
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FatSectorsLeft -= c;
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printf(textScanningFat,100 * (SectorsPerFat - FatSectorsLeft) / SectorsPerFat);
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printf("\r");
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}
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printf("\n");
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if(!FlushClusterBuffer()) {
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return(FALSE);
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}
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return(TRUE);
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}
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FatSize
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pFatDetermineFatSize(
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IN FPFAT_BOOT_SECTOR BootSector
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)
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{
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//
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// For fat32 the # of root dir entries in the bpb is 0.
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//
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if(!BootSector->SectorsPerFat) {
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return(Fat32);
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}
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//
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// See whether we overflow a 12-bit fat and return result.
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//
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return((pFatClusterCount(BootSector) < 4087L) ? Fat12 : Fat16);
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}
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ULONG
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pFatClusterCount(
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IN FPFAT_BOOT_SECTOR BootSector
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)
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{
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ULONG s;
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//
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// Calculate the number of sectors that are in the data area,
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// which is the size of the volume minus the number of sectors
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// that are not in the data area.
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//
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s = BootSector->Sectors ? (ULONG)BootSector->Sectors : BootSector->LargeSectors;
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s -= pFatFirstClusterSector(BootSector);
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return(s / BootSector->SectorsPerCluster);
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}
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ULONG
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pFatFirstClusterSector(
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IN FPFAT_BOOT_SECTOR BootSector
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)
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{
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ULONG s;
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//
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// Calculate the number of sectors that are not
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// part of the data area. This includes reserved sectors,
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// sectors used for the fats, and in the non-fat32 case,
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// sectors used for the root directory.
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//
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// Note that for fat32 the # of root dir entries in the bpb is 0.
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//
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s = BootSector->ReservedSectors;
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s += BootSector->Fats * pFatSectorsPerFat(BootSector);
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s += BootSector->RootEntries / 16;
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return(s);
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}
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ULONG
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pFatSectorsPerFat(
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IN FPFAT_BOOT_SECTOR BootSector
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)
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{
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ULONG SectorsPerFat;
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SectorsPerFat = BootSector->SectorsPerFat
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? (ULONG)BootSector->SectorsPerFat
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: *(FPULONG)((FPBYTE)BootSector + 0x24); // large sectors per fat
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return(SectorsPerFat);
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}
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