/// <summary>
/// Adds a key to the constant database.
/// </summary>
/// <param name="key">The key to add to the database.</param>
/// <param name="data">The data associated with this key.</param>
/// <exception cref="System.IO.IOException">If an error occurs adding the key
/// to the database.</exception>
public void Add(byte[] key, byte[] data)
{
/* Write out the key length. */
CdbUtils.WriteLittleEndianInt32(fileStream, key.Length);
/* Write out the data length. */
CdbUtils.WriteLittleEndianInt32(fileStream, data.Length);
/* Write out the key. */
fileStream.Write(key, 0, key.Length);
/* Write out the data. */
fileStream.Write(data, 0, data.Length);
/* Add the hash pointer to our list. */
int hash = CdbUtils.Hash(key);
hashPointers.Add(new CdbHashPointer(hash, currentKeyPos));
/* Add this item to the count. */
tableCount[hash & 0xff]++;
/* Update the file position pointer. */
PosPlus(8);
PosPlus(key.Length);
PosPlus(data.Length);
}
/// <summary>
/// Finalizes the constant database.
/// </summary>
/// <exception cref="System.IO.IOException">If an error occurs closing out the
/// database.</exception>
public void Finish()
{
if (fileStream == null)
{
return;
}
/* Find the start of each hash table. */
int curEntry = 0;
for (int i = 0; i < 256; i++)
{
curEntry += tableCount[i];
tableStart[i] = curEntry;
}
/* Create a new hash pointer list in order by hash table. */
CdbHashPointer[] slotPointers = new CdbHashPointer[hashPointers.Count];
foreach (CdbHashPointer hp in hashPointers)
{
slotPointers[--tableStart[hp.HashValue & 0xff]] = hp;
}
/* Write out each of the hash tables, building the slot table in
* the process. */
byte[] slotTable = new byte[2048];
for (int i = 0; i < 256; i++)
{
/* Get the length of the hashtable. */
int len = tableCount[i] * 2;
/* Store the position of this table in the slot table. */
slotTable[(i * 8) + 0] = unchecked ((byte)(currentKeyPos & 0xff));
slotTable[(i * 8) + 1] = unchecked ((byte)(((int)((uint)currentKeyPos >> 8)) & 0xff));
slotTable[(i * 8) + 2] = unchecked ((byte)(((int)((uint)currentKeyPos >> 16)) & 0xff));
slotTable[(i * 8) + 3] = unchecked ((byte)(((int)((uint)currentKeyPos >> 24)) & 0xff));
slotTable[(i * 8) + 4 + 0] = unchecked ((byte)(len & 0xff));
slotTable[(i * 8) + 4 + 1] = unchecked ((byte)(((int)((uint)len >> 8)) & 0xff));
slotTable[(i * 8) + 4 + 2] = unchecked ((byte)(((int)((uint)len >> 16)) & 0xff));
slotTable[(i * 8) + 4 + 3] = unchecked ((byte)(((int)((uint)len >> 24)) & 0xff));
/* Build the hash table. */
int curSlotPointer = tableStart[i];
CdbHashPointer[] hashTable = new CdbHashPointer[len];
for (int u = 0; u < tableCount[i]; u++)
{
/* Get the hash pointer. */
CdbHashPointer hp = slotPointers[curSlotPointer++];
/* Locate a free space in the hash table. */
int @where = ((int)((uint)hp.HashValue >> 8)) % len;
while (hashTable[@where] != null)
{
if (++@where == len)
{
@where = 0;
}
}
/* Store the hash pointer. */
hashTable[@where] = hp;
}
/* Write out the hash table. */
for (int u = 0; u < len; u++)
{
CdbHashPointer hp = hashTable[u];
if (hp != null)
{
CdbUtils.WriteLittleEndianInt32(fileStream, hashTable[u].HashValue);
CdbUtils.WriteLittleEndianInt32(fileStream, hashTable[u].EntryPos);
}
else
{
CdbUtils.WriteLittleEndianInt32(fileStream, 0);
CdbUtils.WriteLittleEndianInt32(fileStream, 0);
}
PosPlus(8);
}
}
/* Seek back to the beginning of the file and write out the
* slot table. */
fileStream.Seek(0, SeekOrigin.Begin);
fileStream.Write(slotTable, 0, slotTable.Length);
/* Close the file. */
fileStream.Dispose();
fileStream = null;
}
