private BasePage ReadPageJournal(uint index, BinaryReader reader)
{
// Position cursor
reader.Seek(index * BasePage.PAGE_SIZE);
// Create page instance and read from disk (read page header + content page)
var page = new BasePage();
// target = it's the target position after reader header. It's used when header does not conaints all PAGE_HEADER_SIZE
var target = reader.BaseStream.Position + BasePage.PAGE_HEADER_SIZE;
// read page header
page.ReadHeader(reader);
// Convert BasePage to correct Page Type
if (page.PageType == PageType.Header)
{
page = page.CopyTo <HeaderPage>();
}
else if (page.PageType == PageType.Collection)
{
page = page.CopyTo <CollectionPage>();
}
else if (page.PageType == PageType.Index)
{
page = page.CopyTo <IndexPage>();
}
else if (page.PageType == PageType.Data)
{
page = page.CopyTo <DataPage>();
}
else if (page.PageType == PageType.Extend)
{
page = page.CopyTo <ExtendPage>();
}
// read page content if page is not empty
if (page.PageType != PageType.Empty)
{
// position reader to the end of page header
reader.BaseStream.Seek(target - reader.BaseStream.Position, SeekOrigin.Current);
// read page content
page.ReadContent(reader);
}
return(page);
}
private BasePage ReadPageJournal(BinaryReader reader)
{
var stream = reader.BaseStream;
var posStart = stream.Position * BasePage.PAGE_SIZE;
var posEnd = posStart + BasePage.PAGE_SIZE;
// Create page instance and read from disk (read page header + content page)
var page = new BasePage();
// read page header
page.ReadHeader(reader);
// Convert BasePage to correct Page Type
if (page.PageType == PageType.Header)
{
page = page.CopyTo <HeaderPage>();
}
else if (page.PageType == PageType.Collection)
{
page = page.CopyTo <CollectionPage>();
}
else if (page.PageType == PageType.Index)
{
page = page.CopyTo <IndexPage>();
}
else if (page.PageType == PageType.Data)
{
page = page.CopyTo <DataPage>();
}
else if (page.PageType == PageType.Extend)
{
page = page.CopyTo <ExtendPage>();
}
// read page content if page is not empty
if (page.PageType != PageType.Empty)
{
// read page content
page.ReadContent(reader);
}
// read non-used bytes on page and position cursor to next page
reader.ReadBytes((int)(posEnd - stream.Position));
return(page);
}