The C5 Generic Collection Library for C# and CLI

The C5 Generic Collection Library

for C# and CLI

IT University

of Copenhagen

The C5 Generic Collection Library

C5 is a library of generic collection classes for C# and other CLI languages and works with Microsoft .Net version 2.0 and later, and Mono version 2 and later.

C5 provides functionality and data structures not provided by the standard .Net System.Collections.Generic namespace, such as persistent tree data structures, heap based priority queues, hash indexed array lists and linked lists, and events on collection changes. Also, it is more comprehensive than collection class libraries on other similar platforms, such as Java. Unlike many other collection class libraries, C5 is designed with a strict policy of supporting "code to interface not implementation".

News

1 June: Mikkel Riise Lund's IT University MSc thesis on the first steps in an update of C5 to use Code Contracts and to better fit present-day .NET.
25 May 2011: Version 2.0.0 released at Github and NuGet. This version has been updated to fit the new features of C# 3.0 and C# 4.0 and to be portable to WP7, Silverlight, Xbox and Mono. It is not backwards compatible because eg. C5.Fun<R> has been replaced with System.Func<R> and so on. There is a document describing the changes and rationale. Thanks to Rasmus Nielsen at the IT University for the good work and to many users, not least Marcus Griep, for suggestions and contributions.
17 December 2010: Version 1.1.1 released. Fixes the five bugs found since February 2008. See Release Notes 1.1.1.
10 February 2008: Version 1.1.0 released. Adds implementation of some .NET Framework class library interfaces and fixes the six bugs found since June 2007. See Release Notes 1.1. The book about C5 has been updated also.
8 January 2008: A video with an interview about C5 at MSDN Channel 9 (45 minutes).
1 July 2007: Here's an article in Dr Dobb's Journal.
30 May 2007: Version 1.0.2 released. It fixes the three bugs found since June 2006. See Release Notes 1.0.2.
27 June 2006: Version 1.0.1 released. All known bugs (six) have been fixed, two feature requests accommodated, and the book has been updated. See Release Notes 1.0.1.
30 January 2006: Version 1.0 released.

Downloads and resources

Get C5 version 2.0.0 from Github or NuGet.
Download C5 binaries version 1.1.1: the C5.dll and C5.pdb files as a zip archive.
Download C5 source code version 1.1.1 and unit tests as a zip archive.
Get the book describing C5: Technical report ITU-TR-2006-76 (268 pages):
Get the book's examples as a zip file.
A video with an interview about C5 at MSDN Channel 9 (from January 2008, 45 minutes).
Slides from a talk given at Microsoft Redmond, June 2004. (Much has changed since then).

Functionality

The C5 collection library provides the following collection concepts, described by C# interfaces: Directed enumerable, collection value, directed collection value, extensible collection, collection, sequenced collection, indexed collection, sorted collection, indexed sorted collection, persistent sorted collection, list, LIFO stack, FIFO queue, priority queue, dictionary, and sorted dictionary.

The C5 collection library provides the following data structures, described by C# classes: array list, doubly linked list, hash-indexed array list, hash-indexed linked list, hash set, hash bag (multiset), sorted array, wrapped array, tree set, tree bag (multiset), stack, double-ended queue, circular queue, priority queue (interval heap), hash dictionary, and tree dictionary.

See the relation between interfaces and classes for collections and for dictionaries.

The C5 collection library provides the following unusual functionality on collections and dictionaries: collection update events, multiple updatable list views, reversible enumeration, hash indexes on lists, snapshottable tree-based collections, priority queues with item handles, and in general a design with emphasis on orthogonality, flexibility, and preservation of invariants.

Authors, license and credits

It is based on the GCollections library created by Peter Sestoft during his visit to Microsoft Research, Cambridge in 2001. Niels Kokholm extended the library as a Master's thesis project at the IT University of Copenhagen, advised by Peter Sestoft. Subsequent completion of the library was financed in part by a grant from Microsoft Research University Relations.

Bug reports, feedback and suggestions are welcome, preferably at the Github C5 project site or else to sestoft@itu.dk.

Niels Kokholm and Peter Sestoft; last update 2016-11-06