protected void SplitArea(long offset, long newBoundary)
{
// Split the area pointed to by the offset.
Read(offset, headerBuf, 0, 8);
long curSize = BytesUtil.ReadInt8(headerBuf, 0) & ActiveFlag;
long leftSize = newBoundary;
long rightSize = curSize - newBoundary;
if (rightSize < 0)
{
throw new IOException("Could not split the area.");
}
BytesUtil.WriteInt8(leftSize, headerBuf, 0);
BytesUtil.WriteInt8(rightSize, headerBuf, 8);
// ISSUE: Boundary alteration is a moment when corruption could occur.
// There are three seeks and writes here and when we are setting the
// end points, there is a risk of failure.
// First set the boundary
Write((offset + newBoundary) - 8, headerBuf, 0, 16);
// Now set the end points
Write(offset, headerBuf, 0, 8);
Write((offset + curSize) - 8, headerBuf, 8, 8);
}
public void BuildPage(long buildPageNumber, long position, byte[] pageBuffer, int offset)
{
lock (this) {
File.Read(position, buffer, 0, 36);
var type = BytesUtil.ReadInt8(buffer, 0);
var resourceId = BytesUtil.ReadInt8(buffer, 12);
var pageNumber = BytesUtil.ReadInt8(buffer, 20);
var pageOffset = BytesUtil.ReadInt4(buffer, 28);
var pageLength = BytesUtil.ReadInt4(buffer, 32);
// Some asserts,
if (type != 1)
{
throw new IOException(String.Format("Invalid page type '{0}' at position '{1}'", type, position));
}
if (pageNumber != buildPageNumber)
{
throw new IOException(String.Format(
"The page number '{0}' does not match the number of the page to build ('{1}')", pageNumber, buildPageNumber));
}
// Read the content.
File.Read(position + 36, pageBuffer, offset + pageOffset, pageLength);
}
}
private long GetNextAreaHeader(long offset, long[] header)
{
Read(offset, headerBuf, 0, 8);
long sz = BytesUtil.ReadInt8(headerBuf, 0);
sz = sz & ActiveFlag;
long nextOffset = offset + sz;
if (nextOffset >= DataAreaEndOffset)
{
// Return a 0 sized block
header[0] = 0;
return(-1);
}
Read(nextOffset, headerBuf, 0, 8);
header[0] = BytesUtil.ReadInt8(headerBuf, 0);
return(nextOffset);
}
private long GetPreviousAreaHeader(long offset, long[] header)
{
// If the offset is the start of the file area
if (offset == DataAreaOffset)
{
// Return a 0 sized block
header[0] = 0;
return(-1);
}
Read(offset - 8, headerBuf, 0, 8);
long sz = BytesUtil.ReadInt8(headerBuf, 0);
sz = sz & ActiveFlag;
long previousPointer = offset - sz;
Read(previousPointer, headerBuf, 0, 8);
header[0] = BytesUtil.ReadInt8(headerBuf, 0);
return(previousPointer);
}
public StoreArea(StoreBase store, long id, long offset, bool readOnly)
{
Store = store;
Id = id;
IsReadOnly = readOnly;
store.CheckOffset(offset);
store.Read(offset, buffer, 0, 8);
long v = BytesUtil.ReadInt8(buffer, 0);
if ((v & DeletedFlag) != 0)
{
throw new IOException("Store being constructed on deleted area.");
}
long maxSize = v - 16;
StartOffset = offset + 8;
position = StartOffset;
EndOffset = StartOffset + maxSize;
}
public bool Open()
{
lock (this) {
OpenStore(IsReadOnly);
// If it's small, initialize to empty
if (DataAreaEndOffset < DataAreaOffset)
{
Init();
}
byte[] readBuf = new byte[(int)BinAreaOffset];
Read(0, readBuf, 0, readBuf.Length);
using (var stream = new MemoryStream(readBuf)) {
using (var reader = new BinaryReader(stream)) {
int magic = reader.ReadInt32();
if (magic != Magic)
{
throw new IOException("Format invalid: Magic value is not as expected.");
}
int version = reader.ReadInt32();
if (version != 1)
{
throw new IOException("Format invalid: unrecognized version.");
}
reader.ReadInt64(); // ignore
byte status = reader.ReadByte();
ClosedClean = true;
if (status == 1)
{
// This means the store wasn't closed cleanly.
ClosedClean = false;
}
}
}
// Read the bins
ReadBins();
// Mark the file as open
if (!IsReadOnly)
{
Write(16, 1);
}
long fileLength = DataAreaEndOffset;
if (fileLength <= 8)
{
throw new IOException("Format invalid: File size is too small.");
}
// Set the wilderness offset.
if (fileLength == DataAreaOffset)
{
WildernessOffset = -1;
}
else
{
Read(fileLength - 8, readBuf, 0, 8);
long lastBoundary = BytesUtil.ReadInt8(readBuf, 0);
long lastAreaPointer = fileLength - lastBoundary;
if (lastAreaPointer < DataAreaOffset)
{
throw new IOException("File corrupt: last area offset is before data part of file.");
}
if (lastAreaPointer > fileLength - 8)
{
throw new IOException("File corrupt: last_area_pointer at the end of the file.");
}
Read(lastAreaPointer, readBuf, 0, 8);
long lastAreaHeader = BytesUtil.ReadInt8(readBuf, 0);
// If this is a freed block, then set this are the wilderness offset.
if ((lastAreaHeader & DeletedFlag) != 0)
{
WildernessOffset = lastAreaPointer;
}
else
{
WildernessOffset = -1;
}
}
IsClosed = false;
return(ClosedClean);
}
}
protected void ReadAreaHeader(long offset, long[] header)
{
Read(offset, headerBuf, 0, 16);
header[0] = BytesUtil.ReadInt8(headerBuf, 0);
header[1] = BytesUtil.ReadInt8(headerBuf, 8);
}
