private void FillPages()
{
PHeader pageHeader = new PHeader();
byte[] pageHeaderByteArray = pageHeader.ToByteArray();
int index = 0;
while (index < _buffer.Length)
{
Array.Copy(pageHeaderByteArray, 0, _buffer, index, pageHeaderByteArray.Length);
index += PHeader.PAGE_TOTAL_SIZE;
}
}
private void FillPage(int index, PHeader pageHeader)
{
TypeOfPage pageType = pageHeader.pageType;
CreatePageHeader(index, pageHeader);
BHeader blockHeader = new BHeader();
int blockHeaderIndex = index + PHeader.PAGE_HEADER_SIZE;
while (blockHeaderIndex < index + PHeader.PAGE_TOTAL_SIZE)
{
CreateBlockHeader(blockHeaderIndex, blockHeader);
blockHeaderIndex += BHeader.BLOCK_HEADER_SIZE + pageType.Size;
}
}
public byte[] ReadArray(int index)
{
if (!CheckIndex(index))
{
throw new IndexOutOfRangeException();
}
int pageHeaderIndex = GetPageHeaderIndex(index);
PHeader pageHeader = GetPageHeader(pageHeaderIndex);
TypeOfPage pageType = pageHeader.pageType;
int readArrayLength = pageType.Size;
byte[] readArray = new byte[readArrayLength];
Array.Copy(_buffer, index + BHeader.BLOCK_HEADER_SIZE, readArray, 0, readArrayLength);
return(readArray);
}
private int GetPageFreeBlockIndex(int index)
{
PHeader pageHeader = GetPageHeader(index);
TypeOfPage pageType = pageHeader.pageType;
int blockHeaderIndex = index + PHeader.PAGE_HEADER_SIZE;
while (blockHeaderIndex < index + PHeader.PAGE_TOTAL_SIZE)
{
BHeader blockHeader = GetBlockHeader(blockHeaderIndex);
if (blockHeader.IsFree)
{
return(blockHeaderIndex);
}
blockHeaderIndex += BHeader.BLOCK_HEADER_SIZE + pageType.Size;
}
return(-1);
}
public int MemAllocate(int size)
{
TypeOfPage pageType = PHeader.GetTypeBySize(size);
int pageIndex = 0;
int index = -1;
while (index == -1 && pageIndex < _size - PHeader.PAGE_HEADER_SIZE)
{
PHeader pageHeader = GetPageHeader(pageIndex);
TypeOfPage currentPageType = pageHeader.pageType;
if (currentPageType == pageType)
{
int freeBlockPosition = GetPageFreeBlockIndex(pageIndex);
index = freeBlockPosition >= 0
? freeBlockPosition
: index;
}
else if (currentPageType == TypeOfPage.EMPTY)
{
pageHeader.pageType = pageType;
FillPage(pageIndex, pageHeader);
index = pageIndex + PHeader.PAGE_HEADER_SIZE;
}
pageIndex += PHeader.PAGE_TOTAL_SIZE;
}
if (index >= 0)
{
BHeader blockHeader = GetBlockHeader(index);
blockHeader.IsFree = false;
CreateBlockHeader(index, blockHeader);
}
return(index);
}
public String MemDump()
{
String dump = "";
int index = 0;
while (index < _size)
{
PHeader pageHeader = GetPageHeader(index);
dump += pageHeader.ToString() + '\n';
int pageDataLength = PHeader.PAGE_TOTAL_SIZE - PHeader.PAGE_HEADER_SIZE;
byte[] pageData = new byte[pageDataLength];
Array.Copy(_buffer, index + PHeader.PAGE_HEADER_SIZE, pageData, 0, pageDataLength);
dump += BitConverter.ToString(pageData);
dump += '\n';
index += PHeader.PAGE_TOTAL_SIZE;
}
return(dump);
}
private void CreatePageHeader(int index, PHeader pageHeader)
{
byte[] pageHeaderByteArray = pageHeader.ToByteArray();
Array.Copy(pageHeaderByteArray, 0, _buffer, index, pageHeaderByteArray.Length);
}
