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Allow configurable endianness.
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@dbrant
dbrant committed Oct 8, 2023
1 parent 0a51641 commit 2842310
Showing 1 changed file with 84 additions and 39 deletions.
123 changes: 84 additions & 39 deletions xenixv3/Program.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -41,7 +41,7 @@ static void Main(string[] args)
{
using (var stream = new FileStream(inFileName, FileMode.Open, FileAccess.Read))
{
var partition = new XenixPartition(stream, initialOffset);
var partition = new XenixPartition(stream, initialOffset, PartitionEndianness.Little);
partition.UnpackFiles(baseDirectory);
}
}
Expand All @@ -52,28 +52,81 @@ static void Main(string[] args)
}


private enum PartitionEndianness
{
Little, Big, Pdp11
}

private static ushort GetUInt16(byte[] bytes, int offset, PartitionEndianness endianness)
{
if (endianness == PartitionEndianness.Big)
{
return Utils.BigEndian(BitConverter.ToUInt16(bytes, offset));
}
return Utils.LittleEndian(BitConverter.ToUInt16(bytes, offset));
}

private static uint GetUInt32(byte[] bytes, int offset, PartitionEndianness endianness)
{
if (endianness == PartitionEndianness.Big)
{
return Utils.BigEndian(BitConverter.ToUInt32(bytes, offset));
}
else if (endianness == PartitionEndianness.Pdp11)
{
return Utils.Pdp11EndianInt(bytes, offset);
}
return Utils.LittleEndian(BitConverter.ToUInt32(bytes, offset));
}

private static int Get3ByteInt(byte[] bytes, int offset, PartitionEndianness endianness)
{
int n;
if (endianness == PartitionEndianness.Big)
{
n = (bytes[offset++] << 16);
n |= (bytes[offset++] << 8);
n |= bytes[offset++];
}
else if (endianness == PartitionEndianness.Pdp11)
{
n = (bytes[offset++] << 16);
n |= bytes[offset++];
n |= (bytes[offset++] << 8);
}
else
{
n = bytes[offset++];
n |= (bytes[offset++] << 8);
n |= (bytes[offset++] << 16);
}
return n;
}

private class XenixPartition
{
public const int BLOCK_SIZE_DEFAULT = 0x200;
public const int BLOCK_SIZE_DEFAULT = 0x400;
public const int SUPERBLOCK_BLOCK = 1;
public const int INODES_BLOCK = 2;


public PartitionEndianness endianness;
private Stream stream;
public long partitionBaseOffset;
public SuperBlock superBlock;
private INode rootNode;

private Dictionary<int, INode> inodeCache = new();

public XenixPartition(Stream stream, long baseOffset)
public XenixPartition(Stream stream, long baseOffset, PartitionEndianness endianness)
{
this.stream = stream;
this.partitionBaseOffset = baseOffset;
this.endianness = endianness;

byte[] blockBytes = new byte[BLOCK_SIZE_DEFAULT];

ReadBlock(SUPERBLOCK_BLOCK, blockBytes, 0, blockBytes.Length);
superBlock = new SuperBlock(blockBytes);
superBlock = new SuperBlock(blockBytes, this);

rootNode = ReadINode(stream, 2);
FillChildren(stream, rootNode, 0);
Expand Down Expand Up @@ -153,12 +206,12 @@ private void FillChildren(Stream stream, INode parentNode, int level)

for (int i = 0; i < numDirEntries; i++)
{
var iNodeNum = BitConverter.ToUInt16(contents, i * 0x10);
var iNodeNum = GetUInt16(contents, i * 0x10, endianness);

if (iNodeNum == 0)
continue; // free inode.

var name = Utils.ReplaceInvalidChars(QicUtils.Utils.CleanString(Encoding.ASCII.GetString(contents, i * 0x10 + 2, 0x10 - 2)));
var name = Utils.ReplaceInvalidChars(Utils.CleanString(Encoding.ASCII.GetString(contents, i * 0x10 + 2, 0x10 - 2)));
if (name == "." || name == "..")
continue;

Expand Down Expand Up @@ -225,20 +278,20 @@ private class SuperBlock
public int magic;
public int fsType;

public SuperBlock(byte[] bytes)
public SuperBlock(byte[] bytes, XenixPartition partition)
{
int bytePtr = 0;

totalINodeBlocks = BitConverter.ToUInt16(bytes, bytePtr); bytePtr += 2;
totalVolumeBlocks = (int)Utils.Pdp11EndianInt(bytes, bytePtr); bytePtr += 4;
totalINodeBlocks = GetUInt16(bytes, bytePtr, partition.endianness); bytePtr += 2;
totalVolumeBlocks = (int)GetUInt32(bytes, bytePtr, partition.endianness); bytePtr += 4;

// ...free block list...
// ...free inode list...

bytePtr = 0x19E;
lastModifiedTime = Utils.DateTimeFromTimeT(Utils.Pdp11EndianInt(bytes, bytePtr)); bytePtr += 4;
numFreeDataBlocks = (int)Utils.Pdp11EndianInt(bytes, bytePtr); bytePtr += 4;
numFreeINodes = BitConverter.ToUInt16(bytes, bytePtr); bytePtr += 2;
lastModifiedTime = Utils.DateTimeFromTimeT(GetUInt32(bytes, bytePtr, partition.endianness)); bytePtr += 4;
numFreeDataBlocks = (int)GetUInt32(bytes, bytePtr, partition.endianness); bytePtr += 4;
numFreeINodes = GetUInt16(bytes, bytePtr, partition.endianness); bytePtr += 2;

// ...device information...

Expand All @@ -247,9 +300,9 @@ public SuperBlock(byte[] bytes)
PackName = Utils.CleanString(Encoding.ASCII.GetString(bytes, bytePtr, 6)); bytePtr += 6;
clean = bytes[bytePtr++];

bytePtr = 0x1F8;
magic = (int)Utils.Pdp11EndianInt(bytes, bytePtr); bytePtr += 4;
fsType = (int)Utils.Pdp11EndianInt(bytes, bytePtr); bytePtr += 4;
bytePtr = bytes.Length - 8;
magic = (int)GetUInt32(bytes, bytePtr, partition.endianness); bytePtr += 4;
fsType = (int)GetUInt32(bytes, bytePtr, partition.endianness); bytePtr += 4;

if (fsType == 1)
BlockSize = 0x200;
Expand Down Expand Up @@ -291,38 +344,34 @@ public INode(int id, Stream stream, XenixPartition partition)
stream.Read(bytes, 0, bytes.Length);

int bytePtr = 0;
Mode = BitConverter.ToUInt16(bytes, bytePtr); bytePtr += 2;
nLink = BitConverter.ToUInt16(bytes, bytePtr); bytePtr += 2;
uId = BitConverter.ToUInt16(bytes, bytePtr); bytePtr += 2;
gId = BitConverter.ToUInt16(bytes, bytePtr); bytePtr += 2;
Mode = GetUInt16(bytes, bytePtr, partition.endianness); bytePtr += 2;
nLink = GetUInt16(bytes, bytePtr, partition.endianness); bytePtr += 2;
uId = GetUInt16(bytes, bytePtr, partition.endianness); bytePtr += 2;
gId = GetUInt16(bytes, bytePtr, partition.endianness); bytePtr += 2;

Size = Utils.Pdp11EndianInt(bytes, bytePtr); bytePtr += 4;
Size = GetUInt32(bytes, bytePtr, partition.endianness); bytePtr += 4;

// direct blocks
int block;
for (int i = 0; i < 10; i++)
{
block = (bytes[bytePtr++] << 16);
block |= bytes[bytePtr++];
block |= (bytes[bytePtr++] << 8);
block = Get3ByteInt(bytes, bytePtr, partition.endianness); bytePtr += 3;
if (block != 0)
{
Blocks.Add(block);
}
}

// indirect blocks
int blockPtr = (bytes[bytePtr++] << 16);
blockPtr |= bytes[bytePtr++];
blockPtr |= (bytes[bytePtr++] << 8);
int blockPtr = Get3ByteInt(bytes, bytePtr, partition.endianness); bytePtr += 3;
if (blockPtr != 0)
{
byte[] blockBytes = new byte[partition.superBlock.BlockSize];
stream.Seek(partition.partitionBaseOffset + (blockPtr * partition.superBlock.BlockSize), SeekOrigin.Begin);
stream.Read(blockBytes, 0, blockBytes.Length);
for (int i = 0; i < blockBytes.Length / 4; i++)
{
block = (int)Utils.Pdp11EndianInt(blockBytes, i * 4);
block = (int)GetUInt32(blockBytes, i * 4, partition.endianness);
if (block <= 0)
break;

Expand All @@ -331,17 +380,15 @@ public INode(int id, Stream stream, XenixPartition partition)
}

// double-indirect blocks
blockPtr = (bytes[bytePtr++] << 16);
blockPtr |= bytes[bytePtr++];
blockPtr |= (bytes[bytePtr++] << 8);
blockPtr = Get3ByteInt(bytes, bytePtr, partition.endianness); bytePtr += 3;
if (blockPtr != 0)
{
byte[] iBlockBytes = new byte[partition.superBlock.BlockSize];
stream.Seek(partition.partitionBaseOffset + (blockPtr * partition.superBlock.BlockSize), SeekOrigin.Begin);
stream.Read(iBlockBytes, 0, iBlockBytes.Length);
for (int b = 0; b < iBlockBytes.Length / 4; b++)
{
var iblock = (int)Utils.Pdp11EndianInt(iBlockBytes, b * 4);
var iblock = (int)GetUInt32(iBlockBytes, b * 4, partition.endianness);
if (iblock <= 0)
break;

Expand All @@ -350,7 +397,7 @@ public INode(int id, Stream stream, XenixPartition partition)
stream.Read(blockBytes, 0, blockBytes.Length);
for (int i = 0; i < blockBytes.Length / 4; i++)
{
block = (int)Utils.Pdp11EndianInt(blockBytes, i * 4);
block = (int)GetUInt32(blockBytes, i * 4, partition.endianness);
if (block <= 0)
break;

Expand All @@ -359,9 +406,7 @@ public INode(int id, Stream stream, XenixPartition partition)
}
}

blockPtr = (bytes[bytePtr++] << 16);
blockPtr |= bytes[bytePtr++];
blockPtr |= (bytes[bytePtr++] << 8);
blockPtr = Get3ByteInt(bytes, bytePtr, partition.endianness); bytePtr += 3;
if (blockPtr != 0)
{
Console.WriteLine("FIXME: Add support for triple indirect blocks.");
Expand All @@ -376,9 +421,9 @@ public INode(int id, Stream stream, XenixPartition partition)
// align to 16 bits.
if (bytePtr % 2 != 0) bytePtr++;

AccessTime = Utils.DateTimeFromTimeT(Utils.Pdp11EndianInt(bytes, bytePtr)); bytePtr += 4;
ModifyTime = Utils.DateTimeFromTimeT(Utils.Pdp11EndianInt(bytes, bytePtr)); bytePtr += 4;
CreateTime = Utils.DateTimeFromTimeT(Utils.Pdp11EndianInt(bytes, bytePtr)); bytePtr += 4;
AccessTime = Utils.DateTimeFromTimeT(GetUInt32(bytes, bytePtr, partition.endianness)); bytePtr += 4;
ModifyTime = Utils.DateTimeFromTimeT(GetUInt32(bytes, bytePtr, partition.endianness)); bytePtr += 4;
CreateTime = Utils.DateTimeFromTimeT(GetUInt32(bytes, bytePtr, partition.endianness)); bytePtr += 4;

}
}
Expand Down

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