public IndexTable(IStreamHandler streamCreator, int pageSize, int cacheSize)
{
if (pageSize % 8 != 0)
{
Global.Tracer.Assert(false, "Page size must be divisible by value size: {0}", 8);
}
m_streamCreator = streamCreator;
m_stream = null;
m_nextTempId = -1L;
m_pageSize = pageSize;
m_cacheSize = cacheSize;
m_pageCache = new Dictionary <int, IndexTablePage>(m_cacheSize);
m_queueFirstPage = null;
m_queueLastPage = null;
m_slotsPerPage = m_pageSize / 8;
m_idShift = (int)Math.Log(m_slotsPerPage, 2.0);
}
private IndexTablePage QueueExtractFirst()
{
if (m_queueFirstPage == null)
{
return(null);
}
IndexTablePage queueFirstPage = m_queueFirstPage;
m_queueFirstPage = queueFirstPage.NextPage;
queueFirstPage.NextPage = null;
if (m_queueFirstPage == null)
{
m_queueLastPage = null;
}
else
{
m_queueFirstPage.PreviousPage = null;
}
return(queueFirstPage);
}
private IndexTablePage GetPage(long id)
{
int num = CalcPageNum(id);
IndexTablePage value = null;
if (!m_pageCache.TryGetValue(num, out value))
{
if (m_pageCache.Count == m_cacheSize)
{
if (m_stream == null)
{
m_stream = m_streamCreator.OpenStream();
m_streamCreator = null;
if (!m_stream.CanSeek || !m_stream.CanRead || !m_stream.CanWrite)
{
Global.Tracer.Assert(condition: false, "Must be able to Seek, Read, and Write stream");
}
}
value = QueueExtractFirst();
int pageNumber = value.PageNumber;
m_pageCache.Remove(pageNumber);
if (value.Dirty)
{
long offset = CalcPageOffset(pageNumber);
m_stream.Seek(offset, SeekOrigin.Begin);
value.Write(m_stream);
}
long offset2 = CalcPageOffset(num);
m_stream.Seek(offset2, SeekOrigin.Begin);
value.Read(m_stream);
}
else
{
value = new IndexTablePage(m_pageSize);
}
value.PageNumber = num;
m_pageCache[num] = value;
QueueAppendPage(value);
}
return(value);
}
public long Retrieve(ReferenceID id)
{
IndexTablePage page = GetPage(id.Value);
return(ReadValue(id.Value, page));
}
public void Update(ReferenceID id, long value)
{
IndexTablePage page = GetPage(id.Value);
WriteValue(id.Value, page, value);
}