Ithebula le-ASCII — speedor.net

Ithebula le-ASCII: indlela izinombolo eziyi-128 eziba isisekelo sombhalo

I-ASCII, esifushaniso se-American Standard Code for Information Interchange, iyikhodi eyafundisa amakhompyutha ukuvumelana ngokuthi luyini uhlamvu. Yashicilelwa ngo-1963 futhi yaphuculwa phakathi neminyaka yo-1960, ivumelanisa zonke izinhlamvu eziyisisekelo somqondo wesiNgisi, izinombolo, kanye nezimpawu ezimbalwa zokulawula nezinombolo umshini ongazigcina futhi azidlulise. Uma ucindezela inkinobho yohlamvu olukhulu i-A, ikhompyutha yakho ayigcini isimo, igcina inombolo engu-65. I-ASCII yithebula lokubheka elenza leyo nombolo isho i-A noma kuphi ehambayo.

Leli zinga lidumile ngokufinyeza. I-ASCII iyikhodi ye-7-bit, okusho ukuthi uhlamvu ngalunye lungena kumadijithi we-binary ayisikhombisa futhi wonke umqulu ubandakanya kanye no-2 ephakanyiswe ngo-7, noma amaphoyinti wekhodi angu-128 ahlukene abalwa kusuka ku-0 kuya ku-127. Leyo mfihlo yayenziwe ngamabomu. Amateletypes namamodemu asendulo ayecothile futhi abiza kakhulu, ngakho ibhithi ngayinye yayibalulekile. Amabhithi ayisikhombisa ayenele ukumboza izinhlamvu zesi-Latin eziphakeme nezincane, izinombolo eziyishumi, ukubhalwa okuvamile, kanye nezimpawu zokuxhumana ezazigcina amadivayisi ehambisana kanye, kunebhithi eyodwa esele eyayisetshenziswa izinhlelo eziningi ekuhloleni amaphutha.

Igridi engazinikhinjilizi yezinhlaka zezinhlamvu ezihleliwe ezikhanyayo emibalweni engwevu ye-indigo enokukhanya kwe-cyan negolide — I-ASCII ihlela zonke izinhlamvu egridi eqinile, ehleliwe eyamaseli angu-128 anezinombolo.

Izingxenye ezimbili: izinhlamvu zokulawula nezinhlamvu ezinyekwayo

Ithebula lihlukana kabili ngokucacile. Amakhodi kusuka ku-0 kuya ku-31, kanye nekhodi engu-127 (DEL), ziyizinhlamvu zokulawula. Lezi azinyekisi uphawu esikrinini. Kunalokho ziyala idivayisi ukwenza okuthile: ikhodi engu-9 iyithebhu evundlile, ikhodi engu-10 iwumugqa ozisayo osukelela emugqeni omusha, ikhodi engu-13 iyimpendulo yokuqala emugqeni, kanti ikhodi engu-7 insimbi eyayikade yenza itemenali likhalise ngokuzwakalayo. Ziyi-33 lezi zimpawu zokuxhumana ezikhona sekukonke, futhi nakuba eziningi zingamanje amagugu omlando, umugqa wokuzisa, impendulo yokuqala emugqeni, kanye nethebhu bahlala bebalulekile ekuhleleni amafayela ombhalo namuhla.

Amakhodi kusuka ku-32 kuya ku-126 ayizinhlamvu ezinyekwayo, engu-95 sekukonke. Ikhodi engu-32 yisikhala, esibalwa njengesinyekwayo nakuba singaboniswa lutho ngoba sihambisa isikhombisi phambili. Kusuka lapho uthola ukubhalwa nezimpawu, izinombolo kusuka ku-0 kuya ku-9 emakhodini angu-48 kuya ku-57, izinhlamvu eziphakeme A kuya ku-Z emakhodini angu-65 kuya ku-90, kanye nezinhlamvu ezincane a kuya ku-z emakhodini angu-97 kuya ku-122. Kuvela isici esihle kulesi silinganiso: izinhlobo ezincane neziphakeme zohlamvu olufanayo zihlukana ngo-32 kanye, yingakho ukuguqula ibhithi eyodwa kuguqula isimo. Lezi zinhlobo azizona izingozi, zenziwa ngobuchule ukuze ukuhlela nokuguqula isimo kwenziwe ngezibalo ezilula.

Isishumi, i-hexadecimal, ne-binary: imibono emithathu yenombolo eyodwa

Ikhodi yonke ye-ASCII iyinombolo nje, futhi uzoyibona ibhalwe ngezindlela ezintathu. Isishumi (decimal) yifomu yansuku zonke ye-base-10, ngakho A ingu-65. I-hexadecimal, i-base 16, iyifomu abaqambi bekhodi abayikhethayo ngoba ihambisana namabhayithi: A ingu-0x41, kanti umqulu onyekwayo uhamba kusuka ku-0x20 kuya ku-0x7E. I-binary, i-base 2, iyifomu izinsimbi ezisebenzisa empeleni ukugcina, ngakho A ingu-1000001 kumabhithi ayo ayisikhombisa. Uhlamvu olufanayo, izinqubo ezintathu, futhi ukwazi ukusuka kwenye uye kwenye kuyikhono elibalulekile lapho ufunda ukungenwa kwenkumbulo noma uthumela kwenethiwekhi. Uma usebenza nalezi zinguquko kaningi, umqulu obanzi wamathebula wereferensi ku-speedor.net ugcina lezi zimapha ziseduze.

Izigeleza ze-binary ne-hexadecimal ezikhanyayo zigeleza kumasikhala aziphawu akhanyayo phezu kwesizinda esiwumbala we-navy — I-binary ne-hexadecimal ngokulula amabhesi ahlukene achaza iphoyinti lekhodi le-ASCII elifanayo.

Lapho i-ASCII isabaluleke khona

Bekungaba iphutha ukubeka i-ASCII njengomlando nje. Iyaphila emsebenzini wansuku zonke wanoma ubani othinta ikhodi. Izilimi zohlelo ziphatha imilayo yezintambo, amafayela womthombo, namagama we-protocol njenge-ASCII ezingeni lebhayithi. Ama-protocol wenethiwekhi njenge-HTTP headers, i-SMTP, kanye namafomethi amaningi wesilungiselelo achazwa nge-ASCII ukuze ahlale efundeka umuntu. Lapho intambo ibonakala ilimazekile, abathuthukisi bathatha isibonisi se-hex bafunde amabhayithi angempela emelene nethebula le-ASCII ukubona uphawu lokulawula olungahleliwe noma isiphetho somugqa esingalungile. Ukuhlela kwe-URL, i-Base64, nezinqubo zokuphunyuka konke kwakhelwe kumanani e-ASCII. Kunoma ubani olungisa amaphutha okuhlela, ireferensi esheshayo eduze kwe-amathuluzi abathuthukisi yakho iphendula ibhayithi eyimfihlakalo ibe impendulo ecacile.

Kusuka ku-ASCII kuya ku-Unicode ne-UTF-8

I-ASCII yaphatha isiNgisi kahle kakhulu futhi cishe akukho okunye. Uphahla lwezinhlamvu ezingu-128 alukwazi ukubamba izinhlamvu ezinophawu, i-Cyrillic, isiShayina, isi-Arabhu, noma ama-emoji. I-Unicode yaphendula lokho ngokunikeza inombolo ehlukile, ebizwa ngokuthi iphoyinti lekhodi, kuzo zonke izinhlamvu kuzo zonke izinhlelo zokubhala, manje seziyizinkulungwane ezingaphezu kwekhulu. Okubalulekile, i-Unicode iluhlu lwezinhlamvu, hhayi ifomethi yokugcina, ngakho idinga ikhodi ukuguqula lawo maphoyinti wekhodi abe amabhayithi.

I-UTF-8 yileyo khodi, futhi yisizathu I-ASCII ingazange ishabalale ngempela. I-UTF-8 isebenzisa ibhayithi eyodwa kuya kwezine ngohlamvu ngalunye, futhi yakhelwe ukuze amaphoyinti wekhodi kusuka ku-0 kuya ku-127, wonke umqulu we-ASCII, agcinwe kubhayithi elilodwa elifana ngokuphelele ne-ASCII ecwadini. Lokho kwenza i-UTF-8 ihambisane ngokuphelele nemuva: noma iliphi ifayela le-ASCII eliqinisile selingifayela le-UTF-8 eliqinisile. Izinhlamvu ezingaphezu kuka-127 zisebenzisa amabhayithi engeziwe. Lokhu kuhambisana okuhle yisizathu esikhulu i-UTF-8 manje isekela iningi elikhulu lewebhu. Ngamafuphi, i-ASCII iyisiqu sasekuqaleni sezinhlamvu ezingu-128, i-Unicode iluhlu lomhlaba wonke oluliqukethe, futhi i-UTF-8 iyikhodi ephethe kokubili kuyilapho igcina umbhalo we-ASCII ungaguqukile ibhayithi ngebhayithi.

Imibuzo evame ukubuzwa

Zingaki izinhlamvu ekuthebuleni le-ASCII?

I-ASCII ejwayelekile ichaza izinhlamvu ezingu-128, ezibalwa kusuka ku-0 kuya ku-127. Kulezi, ezingu-95 zizinhlamvu ezinyekwayo kuhlanganise isikhala, kanti ezingu-33 zizinhlamvu zokulawula ezikhomba amadivayisi kunokuba zinyeke uphawu.

Umehluko phakathi kwezinhlamvu zokulawula neziyekwayo uyini?

Izinhlamvu zokulawula, amakhodi 0 kuya ku-31 kanye ne-127, ziyala idivayisi ukwenza okuthile njengomugqa ozisayo noma ithebhu futhi azikhiqizi uphawu olubonakalayo. Izinhlamvu ezinyekwayo, amakhodi 32 kuya ku-126, ziyizinhlamvu, izinombolo, ukubhalwa, kanye nesikhala okubonayo ngempela esikrinini.

Kungani i-ASCII iyikhodi ye-7-bit?

Amabhithi ayisikhombisa anikeza izinhlanganiso ezingu-128 kanye, okwakwanele ukumboza izinhlamvu zesiNgisi, izinombolo, ukubhalwa, kanye nezimpawu zokulawula ngesikhathi kugcinwa ibhande lokudlulisela ehardware yasendulo ecothile. Ibhithi yesishiyagalombili ebhayithini yayivamise ukugcinelwa ukuhlolwa kwamaphutha e-parity.

Ikhodi ye-ASCII yohlamvu A iyini?

I-A ephakeme yisishumi 65, i-hexadecimal 0x41, ne-binary 1000001. I-a encane isishumi 97, okuyisipahla esingu-32 esiphakeme kanye, iphethini eyakhiwe evumela ukuguqula isimo kwenziwe ngezibalo ezilula.

I-ASCII iyafana yini ne-Unicode?

Cha. I-ASCII imboza izinhlamvu ezingu-128, kuyilapho i-Unicode ihlela izinkulungwane ezingaphezu kwekhulu kuzo zonke izinhlelo zokubhala. I-ASCII ngokuphathekile amaphoyinti wekhodi wokuqala angu-128 e-Unicode, ngakho iyingxenye encane yezinga elikhulu.

I-UTF-8 ihlobana kanjani ne-ASCII?

I-UTF-8 iyikhodi ye-Unicode egcina amaphoyinti wekhodi 0 kuya ku-127 kubhayithi elilodwa elifana ngokuphelele ne-ASCII. Lokhu kwenza yonke ifayela le-ASCII ibe ifayela le-UTF-8 eliqinisile, okuyisizathu i-UTF-8 ihambisana nemuva futhi ibusa iwebhu yesimanje.