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/*-
* See the file LICENSE for redistribution information.
*
* Copyright (c) 2009, 2015 Oracle and/or its affiliates. All rights reserved.
*
*/
using System;
using System.Collections;
using System.Collections.Generic;
using System.Text;
using BerkeleyDB.Internal;
namespace BerkeleyDB {
/// <summary>
/// A class providing access to multiple key/data pairs.
/// </summary>
public class MultipleKeyDatabaseEntry : DatabaseEntry,
IEnumerable<KeyValuePair<DatabaseEntry, DatabaseEntry>> {
private bool _recno = false;
internal MultipleKeyDatabaseEntry(
DatabaseEntry dbt, bool recno) {
_data = dbt.UserData;
ulen = dbt.ulen;
_recno = recno;
}
/// <summary>
/// Construct a new bulk buffer for key/data pairs with a formatted
/// byte array.
/// </summary>
/// <param name="data">The formatted byte array</param>
/// <param name="recno">
/// Whether the bulk is for recno/queue database.
/// </param>
public MultipleKeyDatabaseEntry(byte[] data, bool recno) {
UserData = data;
_data = UserData;
_recno = recno;
flags |= DbConstants.DB_DBT_BULK;
}
/// <summary>
/// Construct a new bulk buffer for key/data pairs.
/// </summary>
/// <param name="recno">
/// Whether the bulk buffer is for queue/recno database
/// </param>
/// <param name="data">Enumerable key/data pairs</param>
public MultipleKeyDatabaseEntry(
IEnumerable<KeyValuePair<DatabaseEntry, DatabaseEntry>> data,
bool recno) {
List<byte> list = new List<byte>();
byte[] arr;
int i;
uint pos = 0;
uint size;
if (recno) {
/*
* For recno database, data value is written to the beginning
* of the array, but the record number key is stored in the
* "header" section, along with the offset and length of the
* data value. Offset and length are not stored for the
* recno key, since they are always 4 bytes. The list is
* zero terminated (since -1 is a valid record number):
* -------------------------------------------------------------
* |d1|..|dN|0|lengthN|offsetN|recnoN|..|length1|offset1|recno1|
* -------------------------------------------------------------
*/
List<byte[]> metadata = new List<byte[]>();
foreach (KeyValuePair<DatabaseEntry, DatabaseEntry> pair
in data) {
size = pair.Value.size;
arr = pair.Value.Data;
for (i = 0; i < size; i++)
list.Add(arr[i]);
metadata.Add(pair.Key.Data);
metadata.Add(BitConverter.GetBytes(pos));
metadata.Add(BitConverter.GetBytes(size));
pos += size;
}
for (i = 0; i < 4; i++)
list.Add((byte)0);
for (i = metadata.Count; i > 0; i--) {
for (int j = 0; j < 4; j++)
list.Add(metadata[i - 1][j]);
}
} else {
/*
* For non-recno database, the items are written to the
* array in key/data pairs, but use the same layout as in
* MultipleDatabaseEntry, with DBT.data values at the front
* of the array, and header information at the end of the array.
* --------------------------------------------------------
* |key1|data1|...|keyN|dataN|-1|lenDataN|offDataN| (linewrap)
* --------------------------------------------------------
* |lenKeyN|offKeyN|...|lenData1|offData1||lenKey1|offKey1|
* --------------------------------------------------------
*/
List<uint> metadata = new List<uint>();
foreach (KeyValuePair<DatabaseEntry, DatabaseEntry> pair
in data) {
size = pair.Key.size;
arr = pair.Key.Data;
metadata.Add(pos);
metadata.Add(size);
for (i = 0; i < (int)size; i++)
list.Add(arr[i]);
pos += size;
size = pair.Value.size;
arr = pair.Value.Data;
metadata.Add(pos);
metadata.Add(size);
for (i = 0; i < (int)size; i++)
list.Add(arr[i]);
pos += size;
}
arr = BitConverter.GetBytes(-1);
for (i = 0; i < 4; i++)
list.Add(arr[i]);
for (i = metadata.Count; i > 0; i--) {
arr = BitConverter.GetBytes(metadata[i - 1]);
for (int j = 0; j < 4; j++)
list.Add(arr[j]);
}
}
UserData = list.ToArray();
_data = UserData;
_recno = recno;
flags |= DbConstants.DB_DBT_BULK;
}
/// <summary>
/// Whether the bulk buffer is for recno or queue database.
/// </summary>
public bool Recno {
get { return _recno; }
}
IEnumerator IEnumerable.GetEnumerator() {
return GetEnumerator();
}
/// <summary>
/// Return an enumerator which iterates over all
/// <see cref="DatabaseEntry"/> pairs represented by the
/// <see cref="MultipleKeyDatabaseEntry"/>.
/// </summary>
/// <returns>
/// An enumerator for the <see cref="MultipleDatabaseEntry"/>
/// </returns>
public IEnumerator<KeyValuePair<DatabaseEntry, DatabaseEntry>>
GetEnumerator() {
byte[] darr, karr;
int off, sz;
uint pos, recno;
pos = ulen - 4;
if (_recno) {
recno = BitConverter.ToUInt32(_data, (int)pos);
for (int i = 0; recno > 0;
recno = BitConverter.ToUInt32(_data, (int)pos), i++) {
pos -= 4;
off = BitConverter.ToInt32(_data, (int)pos);
pos -= 4;
sz = BitConverter.ToInt32(_data, (int)pos);
darr = new byte[sz];
Array.Copy(_data, off, darr, 0, sz);
pos -= 4;
yield return new KeyValuePair<DatabaseEntry, DatabaseEntry>(
new DatabaseEntry(BitConverter.GetBytes(recno)),
new DatabaseEntry(darr));
}
} else {
off = BitConverter.ToInt32(_data, (int)pos);
for (int i = 0; off >= 0;
off = BitConverter.ToInt32(_data, (int)pos), i++) {
pos -= 4;
sz = BitConverter.ToInt32(_data, (int)pos);
karr = new byte[sz];
Array.Copy(_data, off, karr, 0, sz);
pos -= 4;
off = BitConverter.ToInt32(_data, (int)pos);
pos -= 4;
sz = BitConverter.ToInt32(_data, (int)pos);
darr = new byte[sz];
Array.Copy(_data, off, darr, 0, sz);
pos -= 4;
yield return new KeyValuePair<DatabaseEntry, DatabaseEntry>(
new DatabaseEntry(karr), new DatabaseEntry(darr));
}
}
}
// public byte[][] Data;
/* No Public Constructor */
//internal MultipleDatabaseEntry(DatabaseEntry dbt) {
// byte[] dat = dbt.UserData;
// List<byte[]> tmp = new List<byte[]>();
// uint pos = dbt.ulen - 4;
// int off = BitConverter.ToInt32(dat, (int)pos);
// for (int i = 0; off > 0; off = BitConverter.ToInt32(dat, (int)pos), i++) {
// pos -= 4;
// int sz = BitConverter.ToInt32(dat, (int)pos);
// tmp.Add(new byte[sz]);
// Array.Copy(dat, off, tmp[i], 0, sz);
// pos -= 4;
// }
// Data = tmp.ToArray();
//}
}
}
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