/// <summary>
/// Reads data from the file.
/// </summary>
/// <param name="volumeIndex">The volume index of the file.</param>
/// <param name="item">The item containing information about the file to read.</param>
/// <param name="buffer">The buffer to read the data</param>
/// <returns>Returns true if the data was read successfully.</returns>
private bool ReadFromFile(int volumeIndex, ref UdfRecord item, ref byte[] buffer)
{
if (item.Size >= MaxExtents)
{
return(false);
}
if (item.IsInline)
{
buffer = item.InlineData;
return(true);
}
buffer = new byte[item.Size];
int position = 0;
for (int i = 0; i < item.Extents.Count; i++)
{
FileExtent e = item.Extents[i];
int length = e.Length;
byte[] b = UdfHelper.Readbytes(position, buffer, buffer.Length);
if (!this.ReadData(volumeIndex, e.PartitionReference, e.Position, length, b))
{
return(false);
}
position += length;
}
return(true);
}
/// <summary>
/// Parses the tag information from the buffer.
/// </summary>
/// <param name="start">The start index of the tag information.</param>
/// <param name="buffer">The buffer containing the data.</param>
/// <param name="size">The number of bytes to read.</param>
/// <returns>Returns true if the data was parsed sucessfully.</returns>
public bool Parse(int start, byte[] buffer, int size)
{
if (buffer == null)
{
throw new ArgumentNullException("buffer");
}
if (size < 16 || (start + size) > buffer.Length || buffer[start + 5] != 0)
{
return(false);
}
int sum = 0;
for (int i = 0; i < 16; i++)
{
if (i != 4)
{
sum = sum + buffer[start + i];
}
}
int m = (sum % 256);
if (m != buffer[start + 4])
{
return(false);
}
this.Identifier = UdfHelper.Get16(start, buffer);
return(true);
}
internal void Parse(byte[] buffer)
{
_size = UdfHelper.Get64(56, buffer);
NumLogBlockRecorded = UdfHelper.Get64(64, buffer);
ATime.Parse(72, buffer);
MTime.Parse(84, buffer);
}
/// <summary>
/// Reads a logical volume descriptor from the buffer.
/// </summary>
/// <param name="buffer">The buffer to read the data from.</param>
/// <returns>Returns true if the descriptor is valid.</returns>
private bool ReadLogicalDescriptor(byte[] buffer)
{
LogicalVolume volume = new LogicalVolume();
volume.Id.Parse(84, buffer);
volume.BlockSize = UdfHelper.Get32(212, buffer);
if (volume.BlockSize < VirtualSectorSize || volume.BlockSize > MaxExtents)
{
return(false);
}
volume.FileSetLocation.Parse(248, buffer);
int numPartitionMaps = UdfHelper.Get32(268, buffer);
if (numPartitionMaps > MaxPartitions)
{
return(false);
}
int position = 440;
for (int index = 0; index < numPartitionMaps; index++)
{
if (position + 2 > SectorSize)
{
return(false);
}
PartitionMap pm = new PartitionMap();
pm.Type = buffer[position];
byte length = buffer[position + 1];
if (position + length > SectorSize)
{
return(false);
}
if (pm.Type == 1)
{
if (position + 6 > SectorSize)
{
return(false);
}
pm.PartitionNumber = UdfHelper.Get16(position + 4, buffer);
}
else
{
return(false);
}
position += length;
pm.PartitionIndex = volume.PartitionMaps.Count;
volume.PartitionMaps.Add(pm);
}
this.LogicalVolumes.Add(volume);
return(true);
}
/// <summary>
/// Reads a partition descriptor from the buffer.
/// </summary>
/// <param name="buffer">The buffer to read the partition data from.</param>
private void ReadPartitionDescriptor(byte[] buffer)
{
var partition = new Partition
{
Number = UdfHelper.Get16(22, buffer),
Position = UdfHelper.Get32(188, buffer),
Length = UdfHelper.Get32(192, buffer)
};
this.Partitions.Add(partition);
}
public void Parse(int start, byte[] buffer)
{
try {
this.FileType = (IcbFileType)buffer[start + 11];
} catch (InvalidCastException) {
this.FileType = IcbFileType.Other;
}
int flags = UdfHelper.Get16(start + 18, buffer);
try {
this.DescriptorType = (IcbDescriptorType)(flags & 3);
} catch (InvalidCastException) {
throw new InvalidOperationException();
}
}
public void Parse(int start, byte[] buffer)
{
Data = UdfHelper.Readbytes(start, buffer, 128);
type = Data[0];
}
public void Parse(int start, byte[] buffer, int size)
{
type = buffer[start];
Data = new byte[size];
Data = UdfHelper.Readbytes(start, buffer, size);
}
public void Parse(int start, byte[] buffer)
{
Data = UdfHelper.Readbytes(start, buffer, 12);
}
/// <summary>
/// Reads the data from the image for a record.
/// </summary>
/// <param name="item">The item to read the data into.</param>
/// <param name="volumeIndex">The index of the volume the file resides on.</param>
/// <param name="lad">The long allocation descriptor of the file.</param>
/// <param name="numRecurseAllowed">The number of recursions allowed before the method fails.</param>
/// <returns>Returns true if the record was read successfully.</returns>
private bool ReadRecordData(UdfRecord item, int volumeIndex, LongAllocationDescriptor lad, int numRecurseAllowed)
{
if (this.itemCount > MaxItems)
{
return(false);
}
LogicalVolume volume = this.LogicalVolumes[volumeIndex];
if (lad.Length != volume.BlockSize)
{
return(false);
}
// Read the record.
int size = lad.Length;
byte[] buffer = new byte[size];
if (!this.ReadData(volumeIndex, lad, buffer))
{
return(false);
}
// Validate the tag is a file.
VolumeTag tag = new VolumeTag();
tag.Parse(0, buffer, size);
if (tag.Identifier != (short)VolumeDescriptorType.File)
{
return(false);
}
// Validate the IcbTage indicates file or directory.
item.IcbTag.Parse(16, buffer);
if (item.IcbTag.FileType != IcbFileType.Directory && item.IcbTag.FileType != IcbFileType.File)
{
return(false);
}
item.Parse(buffer);
int extendedAttrLen = UdfHelper.Get32(168, buffer);
int allocDescriptorsLen = UdfHelper.Get32(172, buffer);
if ((extendedAttrLen & 3) != 0)
{
return(false);
}
int position = 176;
if (extendedAttrLen > size - position)
{
return(false);
}
position += extendedAttrLen;
IcbDescriptorType desctType = item.IcbTag.DescriptorType;
if (allocDescriptorsLen > size - position)
{
return(false);
}
if (desctType == IcbDescriptorType.Inline)
{
// If the file data is inline, read it in now since we have it.
item.IsInline = true;
item.InlineData = UdfHelper.Readbytes(position, buffer, allocDescriptorsLen);
}
else
{
// Otherwise read the information about where the file is located for later.
item.IsInline = false;
item.InlineData = new byte[0];
if ((desctType != IcbDescriptorType.Short) && (desctType != IcbDescriptorType.Long))
{
return(false);
}
for (int index = 0; index < allocDescriptorsLen;)
{
FileExtent extent = new FileExtent();
if (desctType == IcbDescriptorType.Short)
{
if (index + 8 > allocDescriptorsLen)
{
return(false);
}
ShortAllocationDescriptor sad = new ShortAllocationDescriptor();
sad.Parse(position + index, buffer);
extent.Position = sad.Position;
extent.Length = sad.Length;
extent.PartitionReference = lad.Location.PartitionReference;
index += 8;
}
else
{
if (index + 16 > allocDescriptorsLen)
{
return(false);
}
LongAllocationDescriptor ladNew = new LongAllocationDescriptor();
ladNew.Parse(position + index, buffer);
extent.Position = ladNew.Location.Position;
extent.PartitionReference = ladNew.Location.PartitionReference;
extent.Length = ladNew.Length;
index += 16;
}
item.Extents.Add(extent);
}
}
if (item.IcbTag.IsDirectory)
{
if (!item.CheckChunkSizes() || !this.CheckItemExtents(volumeIndex, item))
{
return(false);
}
buffer = new byte[0];
if (!this.ReadFromFile(volumeIndex, ref item, ref buffer))
{
return(false);
}
item._size = 0;
item.Extents.Clear();
size = buffer.Length;
int processedTotal = 0;
int processedCur = -1;
while (processedTotal < size || processedCur == 0)
{
UdfFileInformation fileId = new UdfFileInformation();
fileId.Parse(processedTotal, buffer, (size - processedTotal), ref processedCur);
if (!fileId.IsItLinkParent)
{
// Recursively read the contentst of the drirectory
UdfRecord fileItem = new UdfRecord();
fileItem.Id = fileId.Identifier;
if (fileItem.Id.Data != null)
{
this.fileNameLengthTotal += fileItem.Id.Data.Length;
}
if (this.fileNameLengthTotal > MaxFileNameLength)
{
return(false);
}
fileItem._Parent = item;
item.Subitems.Add(fileItem);
if (item.Subitems.Count > MaxFiles)
{
return(false);
}
this.ReadRecord(fileItem, volumeIndex, fileId.Icb, numRecurseAllowed);
}
processedTotal += processedCur;
}
}
else
{
if (item.Extents.Count > MaxExtents - this.numExtents)
{
return(false);
}
this.numExtents += item.Extents.Count;
if (item.InlineData.Length > MaxInlineExtentsSize - this.inlineExtentsSize)
{
return(false);
}
this.inlineExtentsSize += item.InlineData.Length;
}
this.itemCount++;
return(true);
}
