|
public AccessRange ( long offset, uint size, MemoryMappedFileAccess access = MemoryMappedFileAccess.ReadWrite ) : |
||
| offset | long | The offset within the stream, relative to the end of the stream header. |
| size | uint | The size of the range to access, in bytes. |
| access | MemoryMappedFileAccess | |
| return | ||
public StreamRange AccessRange(long offset, uint size, MemoryMappedFileAccess access = MemoryMappedFileAccess.ReadWrite)
{
unchecked {
long actualBegin = offset + HeaderSize;
uint actualSize = size;
EnsureCapacity(HeaderSize + offset + actualSize);
var viewRef = Cache.CreateView(actualBegin, actualSize, access);
return new StreamRange(
this, viewRef, actualBegin, actualSize
);
}
}
public StreamRange AccessNode(long index, bool forWrite)
{
unchecked {
long position = BTreeHeader.Size + (index * BTreeNode.TotalSize);
var range = IndexStream.AccessRange(position, BTreeNode.TotalSize, MemoryMappedFileAccess.ReadWrite);
var pNode = (BTreeNode *)range.Pointer;
if (pNode->IsValid != 1)
{
// If the node is fully uninitialized, locking it for write is okay
if ((pNode->NumValues != 0) || (pNode->HasLeaves != 0))
{
throw new InvalidDataException();
}
}
if (forWrite)
{
pNode->IsValid = 0;
}
return(range);
}
}
