public long StoreNewChunk(byte[] fromArray, int startingAt, int length)
{
// get the first buffer as result value
long currentBufferNumber = this.AllocateBuffer();
//System.Diagnostics.Debug.WriteLine(" allocating chunk starting at "+currentBufferNumber);
long result = currentBufferNumber;
if (length < 0 || startingAt < 0)
{
throw new LinkedFileException("cannot store negative length chunk (" + startingAt + "," + length + ")");
}
int endingAt = startingAt + length;
// special case: zero length chunk
if (endingAt > fromArray.Length)
{
throw new LinkedFileException("array doesn't have this much data: " + endingAt);
}
int index = startingAt;
// store header with length information
byte[] buffer = new byte[this.buffersize];
BufferFile.Store(length, buffer, 0);
int fromIndex = startingAt;
int firstLength = this.buffersize - BufferFile.INTSTORAGE;
int stored = 0;
if (firstLength > length)
{
firstLength = length;
}
Array.Copy(fromArray, fromIndex, buffer, BufferFile.INTSTORAGE, firstLength);
stored += firstLength;
fromIndex += firstLength;
byte currentBufferType = HEAD;
// store any remaining buffers (no length info)
while (stored < length)
{
// store current buffer and get next block number
long nextBufferNumber = this.AllocateBuffer();
this.SetBuffer(currentBufferNumber, currentBufferType, buffer, 0, buffer.Length, nextBufferNumber);
currentBufferNumber = nextBufferNumber;
currentBufferType = BODY;
int nextLength = this.buffersize;
if (stored + nextLength > length)
{
nextLength = length - stored;
}
Array.Copy(fromArray, fromIndex, buffer, 0, nextLength);
stored += nextLength;
fromIndex += nextLength;
}
// store final buffer
this.SetBuffer(currentBufferNumber, currentBufferType, buffer, 0, buffer.Length, NULLBUFFERPOINTER);
return(result);
}
public byte[] MakeHeader()
{
byte[] result = new byte[this.headersize];
HEADERPREFIX.CopyTo(result, 0);
result[HEADERPREFIX.Length] = VERSION;
int index = HEADERPREFIX.Length + 1;
BufferFile.Store(this.buffersize, result, index);
index += BufferFile.INTSTORAGE;
BufferFile.Store(this.FreeListHead, result, index);
return(result);
}
void SetBuffer(long buffernumber, byte type, byte[] thebuffer, int start, int length, long nextBufferNumber)
{
//System.Diagnostics.Debug.WriteLine(" storing chunk type "+type+" at "+buffernumber);
if (this.buffersize < length)
{
throw new LinkedFileException("buffer size too small " + this.buffersize + "<" + length);
}
byte[] fullbuffer = new byte[length + BUFFEROVERHEAD];
fullbuffer[0] = type;
BufferFile.Store(nextBufferNumber, fullbuffer, 1);
if (thebuffer != null)
{
Array.Copy(thebuffer, start, fullbuffer, BUFFEROVERHEAD, length);
}
this.buffers.SetBuffer(buffernumber, fullbuffer, 0, fullbuffer.Length);
}
public byte[] Dump()
{
ArrayList allbytes = new ArrayList();
int byteCount = 0;
for (int index = 0; index < this.keys.Count; index++)
{
string thisKey = (string)this.keys[index];
byte[] thisValue = (byte[])this.values[index];
byte[] keyprefix = new byte[BufferFile.INTSTORAGE];
byte[] keybytes = BplusTree.StringToBytes(thisKey);
BufferFile.Store(keybytes.Length, keyprefix, 0);
allbytes.Add(keyprefix);
allbytes.Add(keybytes);
byte[] valueprefix = new byte[BufferFile.INTSTORAGE];
BufferFile.Store(thisValue.Length, valueprefix, 0);
allbytes.Add(valueprefix);
allbytes.Add(thisValue);
}
foreach (object thing in allbytes)
{
byte[] thebytes = (byte[])thing;
byteCount += thebytes.Length;
}
int outindex = 0;
byte[] result = new byte[byteCount];
foreach (object thing in allbytes)
{
byte[] thebytes = (byte[])thing;
int thelength = thebytes.Length;
Array.Copy(thebytes, 0, result, outindex, thelength);
outindex += thelength;
}
if (outindex != byteCount)
{
throw new BplusTreeException("error counting bytes in dump " + outindex + "!=" + byteCount);
}
return(result);
}