A library of cross platform C# data structures. Generic B-tree written in C#, which can be replaced with NoSQL database stored in the memory of discharge requirements in real-time (Firebase, Redis Cache, SAP HANA, Exadata, OLTP, etc.). Basic information B-tree can be found in the book N. Wirth, Algorithms + data structures = programs and on Wikipedia, namely:

"In computer science, a B-tree is a self-balancing tree data structure that keeps data sorted and allows searches, sequential access, insertions, and deletions in logarithmic time. The B-tree is a generalization of a binary search tree in that a node can have more than two children (Comer 1979, p. 123). Unlike self-balancing binary search trees, the B-tree is optimized for systems that read and write large blocks of data. B-trees are a good example of a data structure for external memory. It is commonly used in databases and filesystems. (...) Rudolf Bayer and Ed McCreight invented the B-tree while working at Boeing Research Labs in 1971 (Bayer & McCreight 1972), but they did not explain what, if anything, the B stands for." - Wikipedia.

• Methods: BtnAddFirst, BtnCompares, BtnUpdates, BtnAdd, BtnDeleteAll, BtnFind, BtnFirst, BtnLast, BtnNext, BtnPrev, BtnSearch, BtnSearchPrev, BtnUpdate and BtnUsedKeys.

• Methods: BtnAddFirst, BtnCompares, BtnUpdates, BtnAdd, BtnDeleteAll, BtnFind, BtnFirst, BtnLast, BtnNext, BtnPrev, BtnSearch, BtnSearchPrev, BtnUpdate and BtnUsedKeys.
• Methods: BtnFastFind, BtnFastFirst, BtnFastLast, BtnFastNext, BtnFastPrev, BtnFastSearch, BtnFastSearchPrev.

• Methods: BtnAddFirst, BtnCompares, BtnUpdates, BtnAdd, BtnDeleteAll, BtnFind, BtnFirst, BtnLast, BtnNext, BtnPrev, BtnSearch, BtnSearchPrev, BtnUpdate and BtnUsedKeys.
• Methods: BtnFastFind, BtnFastFirst, BtnFastLast, BtnFastNext, BtnFastPrev, BtnFastSearch, BtnFastSearchPrev.

• Methods: BtnAdd, BtnDeleteAll, BtnFind, BtnFirst, BtnLast, BtnNext, BtnPrev, BtnSearch, BtnSearchPrev, BtnUpdate and BtnUsedKeys.
• Methods: BtnFastFind, BtnFastFirst, BtnFastLast, BtnFastNext, BtnFastPrev, BtnFastSearch, BtnFastSearchPrev.

• Methods: BtnAddFirst, BtnCompares, BtnUpdates, BtnAdd, BtnDeleteAll, BtnFind, BtnFirst, BtnLast, BtnNext, BtnPrev, BtnSearch, BtnSearchPrev, BtnUpdate and BtnUsedKeys.

• Methods: BtnAddFirst, BtnCompares, BtnUpdates, BtnAdd, BtnDeleteAll, BtnFind, BtnFirst, BtnLast, BtnNext, BtnPrev, BtnSearch, BtnSearchPrev, BtnUpdate and BtnUsedKeys.
• Methods: BtnFastFind, BtnFastFirst, BtnFastLast, BtnFastNext, BtnFastPrev, BtnFastSearch, BtnFastSearchPrev.

• BtnEnumerator.Multi.sample
• FcsFastBTreeN.Multi.benchmark
• MultipleKeys.Multi.sample
• DuplicityKeys.Multi.sample

A B-tree of order m is a tree which satisfies the following properties:

1. Every node has at most m children.
2. Every non-leaf node (except root) has at least ⌈m/2⌉ children.
3. The root has at least two children if it is not a leaf node.
4. A non-leaf node with k children contains k−1 keys.
5. All leaves appear in the same level.

The benchmark was configured as follows:

• CPU: Intel Xeon E3-1245 @ 3.3 GHz;
• Windows 10, 64bit, .NET Standard 2.0
• 4x4GB DDR3 Kingston @ 1333 MHz

Adding in a single thread:

Foreach in a single thread:

Various methods used throughout the library.

Some data structures require a comparator method to automatically keep their elements sorted upon insertion.

Default comparator is initialized as follows:

protected virtual int BtnCompares(TKey keyX, TKey keyY, object objCmp)
{
  return keyX.CompareTo(keyY);
}

Writing custom class with comparators is easy:

public class MyBtnKeyValue : FcsBTreeN<int, uint>
{
  protected override bool BtnUpdates(int keyAdd, uint valueAdd, ref uint valueUpdates, object objUpdates)
  {
    valueUpdates++;
    return true;
  }
  //////////////////////////
  protected override int BtnCompares(int keyX, int keyY, object objCmp)
  {
    return keyX - keyY;
  }
  //////////////////////////
  public MyBtnKeyValue() : base()
  {
  }
}

Tree gradually passes from the lowest, from the specified keys or higher.

Typical usage:

foreach(KeyValuePair<TKey, TValue>? btnKV in MyBtnKeyValue)
{
}

Other usages:

if (MyBtnKeyValue.BtnFirst(out btnKey, out btnValue) != null)
{
  do
  {
  }
  while (MyBtnKeyValue.BtnNext(ref btnKey, out btnValue) != null)
}

if (MyBtnKeyValue.BtnFind(btnKey, out btnValue) != null)
{
  do
  {
  }
  while (MyBtnKeyValue.BtnNext(ref btnKey, out btnValue) != null)
}

if (MyBtnKeyValue.BtnSearch(ref btnKey, out btnValue) != null)
{
  do
  {
  }
  while (MyBtnKeyValue.BtnNext(ref btnKey, out btnValue) != null)
}

The tree passes successively from the last or entered or lower than the specified key.

Typical usage of iteration in reverse:

if (MyBtnKeyValue.BtnLast(out btnKey, out btnValue) != null)
{
  do
  {
  }
  while (MyBtnKeyValue.BtnPrev(ref btnKey, out btnValue) != null)
}

Other usages:

if (MyBtnKeyValue.BtnFind(btnKey, out btnValue) != null)
{
  do
  {
  }
  while (MyBtnKeyValue.BtnPrev(ref btnKey, out btnValue) != null)
}

if (MyBtnKeyValue.BtnSearchPrev(btnKey, out btnValue) != null)
{
  do
  {
  }
  while (MyBtnKeyValue.BtnPrev(ref btnKey, out btnValue) != null)
}

Methods that seek the desired key and returns the key value pair or null.

Find

The method finds the specified key and returns the key value pair or null.

public virtual  bool? BtnFind(TKey key, out TValue value)
{
}
public virtual KeyValuePair<TKey, TValue>? BtnFind(TKey key)
{
}

First

The method finds the first key and returns the key value pair or null.

public virtual bool? BtnFirst(out TKey key, out TValue value)
{
}
public virtual KeyValuePair<TKey, TValue>? BtnFirst()
{
}

Last

The method finds the last key and returns the key value pair or null.

public virtual bool? BtnLast(out TKey key, out TValue value)
{
}
public virtual KeyValuePair<TKey, TValue>? BtnLast()
{
}

Search

The method finds the specified key or the next higher and returns the key value pair or null.

public virtual bool? BtnSearch(ref TKey key, out TValue value)
{
}
public virtual KeyValuePair<TKey, TValue>? BtnSearch(TKey key)
{
}

SearchPrev

The method finds the specified key or the previous and returns the key value pair or null.

public virtual bool? BtnSearchPrev(ref TKey key, out TValue value)
{
}
public virtual KeyValuePair<TKey, TValue>? BtnSearchPrev(TKey key)
{
}

• Methods: Append, Close, Length, Open, Position, Read, Seek, Write.

• FcsInmemStream.Multi.sample

The benchmark was configured as follows:

• CPU: Intel Xeon E3-1245 @ 3.3 GHz;
• Windows 10, 64bit, .NET Standard 2.0
• 4x4 GB DDR3 Kingston @ 1333 MHz
• Append, Read, Write (cache 1,000 T) and foreach (cache 128 T)

Instal Visual Studio 2017 version 15.4.0 preview 3.0 & .NET Core 2.0 & support for multiple target frameworks

• Pre-release Visual Studio 2017 | Visual Studio Preview
• Visual Studio 2017 (version 15.4 - Preview 3.0) Release Notes
• Announcing .NET Core 2.0
• GitHUB .NET Core
• .NET Core 2.0 download

Install via Nuget Package Manager version 2.0.0

PM> Install-Package FriendlyCSharp.Databases

See the LICENSE.