using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
namespace RaptorDB
{
internal class BitmapIndex
{
public BitmapIndex(string path, string filename)
{
_FileName = Path.GetFileNameWithoutExtension(filename);
_Path = path;
if (_Path.EndsWith("\\") == false) _Path += "\\";
_recordFileRead = new FileStream(_Path + _FileName + _recExt, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);
_recordFileWrite = new FileStream(_Path + _FileName + _recExt, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);
_bitmapFileWrite = new FileStream(_Path + _FileName + _bmpExt, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);
_bitmapFileRead = new FileStream(_Path + _FileName + _bmpExt, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);
_bitmapFileWrite.Seek(0L, SeekOrigin.End);
_lastBitmapOffset = _bitmapFileWrite.Length;
_lastRecordNumber = (int)(_recordFileRead.Length / 8);
}
private string _recExt = ".mgbmr";
private string _bmpExt = ".mgbmp";
private string _FileName = "";
private string _Path = "";
private FileStream _bitmapFileWrite;
private FileStream _bitmapFileRead;
private FileStream _recordFileRead;
private FileStream _recordFileWrite;
private long _lastBitmapOffset = 0;
private int _lastRecordNumber = 0;
//private object _lock = new object();
private SafeDictionary<int, WAHBitArray> _cache = new SafeDictionary<int, WAHBitArray>();
private SafeDictionary<int, long> _offsetCache = new SafeDictionary<int, long>();
ILog log = LogManager.GetLogger(typeof(BitmapIndex));
#region [ P U B L I C ]
public void Shutdown()
{
log.Debug("Shutdown BitmapIndex");
bool d1 = false;
bool d2 = false;
Flush();
if (_recordFileRead != null)
{
if (_recordFileWrite.Length == 0) d1 = true;
if (_bitmapFileWrite.Length == 0) d2 = true;
_recordFileRead.Close();
_recordFileWrite.Close();
_bitmapFileWrite.Close();
_bitmapFileRead.Close();
if (d1)
File.Delete(_Path + _FileName + _recExt);
if (d2)
File.Delete(_Path + _FileName + _bmpExt);
_recordFileRead = null;
_recordFileWrite = null;
_bitmapFileRead = null;
_bitmapFileWrite = null;
}
}
public void Flush()
{
if (_recordFileWrite != null)
_recordFileWrite.Flush();
if (_bitmapFileWrite != null)
_bitmapFileWrite.Flush();
}
public int GetFreeRecordNumber()
{
int i = _lastRecordNumber++;
_cache.Add(i, new WAHBitArray());
return i;
}
public void Commit(bool freeMemory)
{
foreach (KeyValuePair<int, WAHBitArray> kv in _cache)
{
if (kv.Value.isDirty)
{
SaveBitmap(kv.Key, kv.Value);
kv.Value.FreeMemory();
kv.Value.isDirty = false;
}
}
Flush();
if (freeMemory)
{
_cache = new SafeDictionary<int, WAHBitArray>();
}
}
public void SetDuplicate(int bitmaprecno, int record)
{
WAHBitArray ba = null;
ba = GetBitmap(bitmaprecno);
ba.Set(record, true);
}
public WAHBitArray GetBitmap(int recno)
{
return internalGetBitmap(recno);//, true);
}
//public WAHBitArray GetBitmapNoCache(int recno)
//{
// return internalGetBitmap(recno, true); // is false needed ??
//}
//public void OptimizeIndex()
//{
//// FEATURE : optimize index here
//lock (_lock)
//{
// _internalOP = true;
// _lastBitmapOffset = 0;
// _bitmapFile.Flush();
// _bitmapFile.Close();
// // compact bitmap index file to new file
// _bitmapFile = new FileStream(_Path + _FileName + ".bitmap$", FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);
// MemoryStream ms = new MemoryStream();
// BinaryWriter bw = new BinaryWriter(ms, Encoding.UTF8);
// // save words and bitmaps
// using (FileStream words = new FileStream(_Path + _FileName + ".words", FileMode.Create))
// {
// foreach (KeyValuePair<string, Cache> kv in _index)
// {
// bw.Write(kv.Key);
// uint[] ar = LoadBitmap(kv.Value.FileOffset);
// long offset = SaveBitmap(ar, ar.Length, 0);
// kv.Value.FileOffset = offset;
// bw.Write(kv.Value.FileOffset);
// }
// // save words
// byte[] b = ms.ToArray();
// words.Write(b, 0, b.Length);
// words.Flush();
// words.Close();
// }
// // rename files
// _bitmapFile.Flush();
// _bitmapFile.Close();
// File.Delete(_Path + _FileName + ".bitmap");
// File.Move(_Path + _FileName + ".bitmap$", _Path + _FileName + ".bitmap");
// // reload everything
// _bitmapFile = new FileStream(_Path + _FileName + ".bitmap", FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite);
// _lastBitmapOffset = _bitmapFile.Seek(0L, SeekOrigin.End);
// _internalOP = false;
//}
//}
#endregion
#region [ P R I V A T E ]
private WAHBitArray internalGetBitmap(int recno)//, bool usecache)
{
WAHBitArray ba = new WAHBitArray();
if (recno == -1)
return ba;
if (_cache.TryGetValue(recno, out ba))
{
return ba;
}
else
{
long offset = 0;
if (_offsetCache.TryGetValue(recno, out offset) == false)
{
byte[] b = new byte[8];
long off = ((long)recno) * 8;
_recordFileRead.Seek(off, SeekOrigin.Begin);
_recordFileRead.Read(b, 0, 8);
offset = Helper.ToInt64(b, 0);
_offsetCache.Add(recno, offset);
}
ba = LoadBitmap(offset);
//if (usecache)
_cache.Add(recno, ba);
return ba;
}
}
private void SaveBitmap(int recno, WAHBitArray bmp)
{
long offset = SaveBitmapToFile(bmp);
long v;
if (_offsetCache.TryGetValue(recno, out v))
_offsetCache[recno] = offset;
else
_offsetCache.Add(recno, offset);
long pointer = ((long)recno) * 8;
_recordFileWrite.Seek(pointer, SeekOrigin.Begin);
byte[] b = new byte[8];
b = Helper.GetBytes(offset, false);
_recordFileWrite.Write(b, 0, 8);
}
//-----------------------------------------------------------------
// BITMAP FILE FORMAT
// 0 'B','M'
// 2 uint count = 4 bytes
// 6 Bitmap type 0 = int record list 1 = uint bitmap
// 7 '0'
// 8 uint data
//-----------------------------------------------------------------
private long SaveBitmapToFile(WAHBitArray bmp)
{
long off = _lastBitmapOffset;
uint[] bits = bmp.GetCompressed();
byte[] b = new byte[bits.Length * 4 + 8];
// write header data
b[0] = ((byte)'B');
b[1] = ((byte)'M');
Buffer.BlockCopy(Helper.GetBytes(bits.Length, false), 0, b, 2, 4);
b[6] = (byte)(1);// (byte)(bmp.UsingIndexes == true ? 0 : 1);
b[7] = (byte)(0);
for (int i = 0; i < bits.Length; i++)
{
byte[] u = Helper.GetBytes((int)bits[i], false);
Buffer.BlockCopy(u, 0, b, i * 4 + 8, 4);
}
_bitmapFileWrite.Write(b, 0, b.Length);
_lastBitmapOffset += b.Length;
return off;
}
private WAHBitArray LoadBitmap(long offset)
{
WAHBitArray bc = new WAHBitArray();
if (offset == -1)
return bc;
List<uint> ar = new List<uint>();
WAHBitArray.TYPE type = WAHBitArray.TYPE.Compressed_WAH;
FileStream bmp = _bitmapFileRead;
{
bmp.Seek(offset, SeekOrigin.Begin);
byte[] b = new byte[8];
bmp.Read(b, 0, 8);
if (b[0] == (byte)'B' && b[1] == (byte)'M' && b[7] == 0)
{
type = (b[6] == 0 ? WAHBitArray.TYPE.Indexes : WAHBitArray.TYPE.Compressed_WAH);
int c = Helper.ToInt32(b, 2);
byte[] buf = new byte[c * 4];
bmp.Read(buf, 0, c * 4);
for (int i = 0; i < c; i++)
{
ar.Add((uint)Helper.ToInt32(buf, i * 4));
}
}
}
bc = new WAHBitArray(type, ar.ToArray());
return bc;
}
#endregion
}
}
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