Changes between Version 37 and Version 38 of LibrariesUnderConstruction
- Timestamp:
- Feb 16, 2009, 9:13:02 PM (14 years ago)
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LibrariesUnderConstruction
v37 v38 49 49 --------------------------------------------------------------------------------------------------- 50 50 == Boost.!AsynchronousExecutors == 51 * '''Author(s):''' Vicente J. Botet Escrib a51 * '''Author(s):''' Vicente J. Botet Escribá 52 52 * '''Version:''' 0.4 53 53 * '''State:''' Quite Stable … … 181 181 == Boost.!ConstantTimeSize == 182 182 183 * '''Author(s):''' Vicente J. Botet Escrib a183 * '''Author(s):''' Vicente J. Botet Escribá 184 184 * '''Version:''' 0.1 185 185 * '''State:''' Stable … … 294 294 --------------------------------------------------------------------------------------------------- 295 295 == Boost.!InterThreads == 296 * '''Author(s):''' Vicente J. Botet Escrib a296 * '''Author(s):''' Vicente J. Botet Escribá 297 297 * '''Version:''' 0.4 298 298 * '''State:''' Quite Stable … … 338 338 339 339 --------------------------------------------------------------------------------------------------- 340 == Boost.LUID == 341 * '''Author(s):''' Vicente J. Botet Escribá 342 * '''Version:''' 0.0.0 343 * '''State:''' Prototype 344 * '''Last upload:''' 2009 Fev 16 345 * '''Categories:''' [#DataStructures Data Structures] 346 * '''Links:''' [https://svn.boost.org/svn/boost/sandbox/luid Boost Sandbox] 347 * '''Description:''' Boost.LUID simplifies the generation of locally unique identifiers in a wide context. 348 349 Locally Unique Identifier or LUID is a special type of identifier used in software applications in order to provide a reference number which is unique in a given context (hence, "Locally" in opposition to "Globally" or "Universally"). Each generated LUID is guaranteed to be unique in its context. 350 351 LUID could have many applications. Some examples follow: creating unique identifiers in a database tables, network messages may be identified with a LUID to ensure that this messages are associated to a given session, transactions may be identified by LUIDs. 352 353 Note. Please let me know other applications of luids you can have. 354 355 * Reduced identifier size 356 357 An attractive feature of LUIDs when compared to alternatives is the minimal size used by this identifiers, that depends on the number of instances a given context can have (usually 4 bytes). This allows to use them in protocols fixing the size of the references exchanged to less that 16 bytes(as it is the case of UUID and GUID). Usually LUIDs are represented by unsigned integers and have an upper bound value. 358 359 * Usable as random access index in constant time 360 361 Another aspect, and not less interesting is that the access to the information they identify can be done in constant time. 362 363 * Recovering unused identifiers 364 365 A first implementation could consists in a monotonic counter. 366 367 The drawback of having a small size is that the number of unique identifier is more limited. This limit will finish by been reached if the application runs a long time. To palliate to this, we need a mechanism to recover the unused identifiers once the identified information is removed. Depending on the application the recovered identifiers should be discarded, reused immediately or frozen during a given duration or a number of times. 368 369 Usually they are reused in a first reusable first reused order (fifo), but depending on the implementation this could not be always the more efficient policy. So the user can either constraint this fifo order or let undefined this aspect. 370 371 * Managing the lack of identifiers 372 373 In any case we need to manage with the overflow case, i.e. when there are no more free identifiers. The user could prefer an exception, return an invalid value, use errno, or call to a user defined function which could try to recover from this situation, by re dimensioning the upper bound for example. 374 375 * Ensuring coherency on reusable identifiers 376 377 All this seams to work up to the user do not release the same identifiers twice. As this is an expensive aspect, but usually the applications has its own way to do it. If this is not the case the application could ask to the luid generator to ensure that. 378 379 * Synchronization on multi threaded or multi process applications 380 381 The generation of new LUIDs and the recovering of unused LUIDs must be synchronized. So LUID are better adapted to systems where these operations are done in a reduced scope. Depending on this scope: single thread, multi-threaded process or a node,i.e. multiple process, the synchronization mechanisms vary. In a single thread scope no synchronization is needed. Synchronization on a multi-threaded process can be ensured using a thread mutex. 382 383 In addition the synchronization can be ensured internally by the generator, or externally by the user, i.e. the user has already a synchronization mechanism. 384 385 LUIDs are not adapted to distributed system (multiple nodes generating and recovering luids) because it needs a coordination between the different nodes which will take too much time. UUIDs and GUIDs are more adapted to this situation. Anyway if the size constraint can not be avoided, one of the nodes could play the master role and the others behaves as slaves. Master and slaves need to work together. This library do not pretend to take in account this use case but, could be the base of such approach. 386 387 * Persistency 388 389 Another aspect is the lifetime of the information to be identified by the luids. It can be the lifetime of the process, the host machine lifetime or persists to a shut down of the host machine using the file-system. 390 391 * Optimization 392 393 The last aspect will be the optimization. Different application have different needs, some have space constraints, and mot of the others have speed constraints. 394 395 --------------------------------------------------------------------------------------------------- 340 396 == Boost.Mirror == 341 397 * '''Author(s):''' Matus Chochlik … … 412 468 --------------------------------------------------------------------------------------------------- 413 469 == Boost.!RendezVous == 414 * '''Author(s):''' Vicente J. Botet Escrib a470 * '''Author(s):''' Vicente J. Botet Escribá 415 471 * '''Version:''' 0.0.0 416 472 * '''State:''' Draft … … 433 489 -------------------------------------------------------------------------------------------------- 434 490 == Boost.Synchro == 435 * '''Author(s):''' Vicente J. Botet Escrib a491 * '''Author(s):''' Vicente J. Botet Escribá 436 492 * '''Version:''' 0.0.0 437 493 * '''State:''' Draft … … 450 506 --------------------------------------------------------------------------------------------------- 451 507 == Boost.!ThreaderJoiner == 452 * '''Author(s):''' Vicente J. Botet Escrib a508 * '''Author(s):''' Vicente J. Botet Escribá 453 509 * '''Version:''' 0.4 454 510 * '''State:''' Quite Stable … … 539 595 --------------------------------------------------------------------------------------------------- 540 596 == Accumulators.Ext == 541 * '''Suggested by:''' Vicente J. Botet Escrib a597 * '''Suggested by:''' Vicente J. Botet Escribá 542 598 * '''Categories:''' [#MathAndNumerics Math And Numerics] 543 599 * '''Description:''' Adding sliding, dependable and cyclic accumulators to Boost.Accumulators. … … 602 658 --------------------------------------------------------------------------------------------------- 603 659 == !ConstraintsProgramming == 604 * '''Suggested by:''' Vicente J. Botet Escrib a660 * '''Suggested by:''' Vicente J. Botet Escribá 605 661 * '''Categories:''' [] 606 662 * '''Description:''' Constraints programming is a programming paradigm where relations between variables are stated in the form of constraints. Constraints differ from the common primitives of imperative programming languages in that they do not specify a step or sequence of steps to execute, but rather the properties of a solution to be found. This makes Constraint Programming a form of declarative programming. … … 620 676 --------------------------------------------------------------------------------------------------- 621 677 == !DenseSet == 622 * '''Suggested by:''' Vicente J. Botet Escrib a678 * '''Suggested by:''' Vicente J. Botet Escribá 623 679 * '''Categories:''' [#Containers Containers] 624 680 * '''Description:''' Implementation of dense set of integers using intervals. … … 626 682 --------------------------------------------------------------------------------------------------- 627 683 == Frames == 628 * '''Suggested by:''' Vicente J. Botet Escrib a684 * '''Suggested by:''' Vicente J. Botet Escribá 629 685 * '''Categories:''' [#InputOutput Input/Output] 630 686 * '''Description:''' Library based on an extension of the Archive concept making it bidirectional. … … 744 800 }}} 745 801 746 ---------------------------------------------------------------------------------------------------747 == LUID ==748 * '''Suggested by:''' Vicente J. Botet Escriba749 * '''Categories:''' [#DataStructures Data Structures]750 * '''Description:''' Locally Unique Identifier or LUID is a special type of identifier used in software applications in order to provide a reference number which is unique in a given context (hence, "Locally" in opposition to "Globally" or "Universally"). Each generated LUID is guaranteed to be unique in its context.751 752 LUID could have many applications. Some examples follow: creating unique identifiers in a database tables, network messages may be identified with a LUID to ensure that this messages are associated to a given session, transactions may be identified by LUIDs.753 802 754 803 --------------------------------------------------------------------------------------------------- 755 804 == Quartets == 756 * '''Suggested by:''' Vicente J. Botet Escrib a805 * '''Suggested by:''' Vicente J. Botet Escribá 757 806 * '''Categories:''' [#Containers Containers] [#DataStructures Data Structures] 758 807 * '''Description:''' Quartet are half an octet, i.e. 4 bits taking values from 0..15, and usually represented by chars '0'-'9' 'A'-'F'. … … 763 812 --------------------------------------------------------------------------------------------------- 764 813 == !SpreadSheet == 765 * '''Suggested by:''' Vicente J. Botet Escrib a814 * '''Suggested by:''' Vicente J. Botet Escribá 766 815 * '''Categories:''' [] 767 816 * '''Description:''' Allows to manage with the underlying concepts of a Spreadsheet but without displaying them. … … 809 858 --------------------------------------------------------------------------------------------------- 810 859 == STM == 811 * '''Suggested by:''' Vicente J. Botet Escrib a860 * '''Suggested by:''' Vicente J. Botet Escribá 812 861 * '''Categories:''' [#ConcurrentProgramming Concurrent Programming] 813 862 * '''Description:''' Transactional memory (TM) is a recent parallel programming concept which reduces challenges found in parallel programming. TM offers numerous advantages over other synchronization mechanisms. … … 880 929 == Data Structures == 881 930 * [#Boost.Fsm Boost.Fsm] 882 * [# LUIDLUID]931 * [#Boost.LUID Boost.LUID] 883 932 * [#Boost.Msm Boost.Msm] 884 933 * [#Quartets Quartets]
