mirror of
https://github.com/ultimatepp/ultimatepp.git
synced 2026-05-17 06:06:00 -06:00
53 lines
4.1 KiB
C++
53 lines
4.1 KiB
C++
TITLE("NTLvsSTL")
|
|
TOPIC_TEXT(
|
|
"[ $$0,0#00000000000000000000000000000000:Default][l288;i704;a17;O9;~~~.992; $$1,"
|
|
"0#10431211400427159095818037425705:param][a83;*R6 $$2,5#3131016247420302412518841"
|
|
"7583966:caption][b83;* $$3,5#07864147445237544204411237157677:title][b167;a42;C $"
|
|
"$4,6#40027414424643823182269349404212:item][b42;a42; $$5,5#4541300047534217475409"
|
|
"1244180557:text][l288;a17; $$6,6#27521748481378242620020725143825:desc][l321;t246"
|
|
";C@5;1 $$7,7#20902679421464641399138805415013:code][b2503; $$8,0#6514237545610002"
|
|
"3862071332075487:separator][*@(0.0.255) $$9,0#83433469410354161042741608181528:ba"
|
|
"se][t4167;C+117 $$10,0#37138531426314131251341829483380:class][l288;a17;*1 $$11,1"
|
|
"1#70004532496200323422659154056402:requirement][i416;b42;a42;O9;~~~.416; $$12,12#"
|
|
"10566046415157235020018451313112:tparam][b167;C $$13,13#9243045944346046191110808"
|
|
"0531343:item1][a42;C $$14,14#77422149456609303542238260500223:item2][*@2$(0.128.1"
|
|
"28) $$15,15#34511555403152284025741354420178:NewsDate][l321;*C$7 $$16,16#03451589"
|
|
"433145915344929335295360:result][l321;b83;a83;*C$7 $$17,17#0753155046352950537122"
|
|
"8428965313:result`-line][l160;t4167;*C+117 $$18,5#8860394944220582595880005322242"
|
|
"5:package`-title][{_}%EN-US [s2; NTL - STL Comparis[%00-00 on]&][s5; NTL was crea"
|
|
"ted to solve following problems we used to encounter when using STL: &][s3; Copy-"
|
|
"constructible requirements&][s5; STL requires the elements stored in containers t"
|
|
"o meet the requirements of copy-constructible and assignable types. This causes t"
|
|
"wo problems:&][s5;i150;O2; Elements that do not satisfy these requirements cannot"
|
|
" be directly stored in STL containers.&][s5;i150;O2; For many types of elements, "
|
|
"including STL containers themselves, copy-constructor and assign operator is a ve"
|
|
"ry expensive operation, that is why often they cannot be stored in STL containers"
|
|
" effectively.&][s5; NTL addresses this problem by introducing [^dpp`:`/`/SourceDo"
|
|
"c`/Containers`/Overview^ Vector] and [^dpp`:`/`/SourceDoc`/Containers`/Overview^ "
|
|
"Array] flavors of containers.&][s3; Value transfer&][s5; ")
|
|
TOPIC_TEXT(
|
|
"Content of STL containers can be transfered only using expensive deep-copy const"
|
|
"ructor/assigment operator. This causes performance problems especially when using"
|
|
" STL containers as function return values, but lack of better functionality is mi"
|
|
"ssing elsewhere too. NTL provides [^dpp`:`/`/SourceDoc`/Containers`/pick`_^ trans"
|
|
"fer semantics] concepts to deal with this problem.&][s3; Random access and random"
|
|
" access notation&][s5; STL uses iterators as the preferred way how to access and "
|
|
"identify elements in containers. While this is generally the most generic way, re"
|
|
"al-life problems often require or at least benefit from random access using indic"
|
|
"es. NTL provides fast random access to all kinds of containers and NTL interfaces"
|
|
" prefer notation using indices. As a side effect, NTL user can completely avoid u"
|
|
"sing iterators in favor of indices, which in current C`++ results in much simpler"
|
|
" and less verbose syntax (using modern optimizing compilers there is no differenc"
|
|
"e in performance).&][s3; Index&][s5; A completely new type of associative contain"
|
|
"er, [^dpp`:`/`/`:`:`/Index`<class T`, class HashFn `= StdHash`<T`> `>`/template `"
|
|
"<class T`, class HashFn `= StdHash`<T`> `> class Index^ Index], is introduced, as"
|
|
" an ideal building block for all kinds of associative operations.&][s3; Algorithm"
|
|
" requirements&][s5; Requirements of STL algorithms are very loosely defined. NTL "
|
|
"tries to provide more specific requirements and also minimal ones. This allows e."
|
|
"g. [^dpp`:`/`/www`/pages`/polyarray^ direct sorting of Array of polymorphic eleme"
|
|
"nts].&][s3; Minor improvements&][s5; There are also some minor improvements:&][s5"
|
|
";i150;O2; Besides [* reserve] present in STL, NTL provides also [* Shrink] method"
|
|
" to minimize a container's memory consumption.&][s5;i150;O2; Iterators can be ass"
|
|
"igned a NULL value.&][s5;i150;O2; Associative containers are based on hashing to "
|
|
"provide better performance. Utility classes and functions are provided to support"
|
|
" building correct hashing functions.")
|