ECMA 121-2000 8-Bit Single-Byte Coded Graphic Character sets Latin Hebrew Alphabet (2nd Edition)《8-位单字节编码的图形字符集 拉丁 希伯来字母 第2版》.pdf

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1、Standard ECMA-1212ndEdition - December 2000Standardizing Information and Communication SystemsPhone: +41 22 849.60.00 - Fax: +41 22 849.60.01 - URL: http:/www.ecma.ch - Internet: helpdeskecma.ch8-Bit Single-Byte CodedGraphic Character sets:Latin/Hebrew Alphabet.Standard ECMA-1212ndEdition - December

2、 2000Standardizing Information and Communication SystemsPhone: +41 22 849.60.00 - Fax: +41 22 849.60.01 - URL: http:/www.ecma.ch - Internet: helpdeskecma.chMB ECMA-121.DOC 19-12-00 17,428-Bit Single-Byte CodedGraphic Character sets:Latin/Hebrew Alphabet.Brief HistoryThe adoption of Standard ECMA-6 (

3、ISO 646) in 1965 as the agreed international 7-bit code for informationinterchange has led to the development of many national, international and application-oriented versions of this codewhich have been in wide use for quite some time.These versions had a number of limitations generally inherent to

4、 the size of the code: they did not provide all graphic characters which may be needed, for some characters, specially for accented letters, it was necessary to resort to BACKSPACE sequences, whichcreated problems when processing data containing such composite characters, interchange among different

5、 versions was practically limited to the 82 common graphic characters.With the advent of 8-bit coding it was possible to increase the number of graphic characters. ISO 6937/2, forexample, provided a character set covering the requirements of most languages based on the Latin alphabet. Thischaracter

6、set, although well suited for text communication, was difficult to use for processing as some graphiccharacters were represented by one and others by two bit combinations. Thus, the need was recognized for codedgraphic character sets, each of which: is the same for all users of a given area, provide

7、s single-byte coding of all graphic characters thus permitting easy processing, takes into account character sets used in the industry.Since 1982 the urgency of the need for an 8-bit single-byte coded character set was recognized in ECMA as well as inANSI/X3L2 and numerous working papers were exchan

8、ged between the two groups. In February 1984 ECMA TC1submitted to ISO/TC97/SC2 (which has become ISO/IEC JTC 1/SC2 in 1987) a proposal for such a coded characterset. At its meeting of April 1984 SC2 decided to propose a new item of work for this topic. Technical discussionsduring and after this meet

9、ing led TC1 to adopt the coding scheme proposed by X3L2. International Standard ISO/IEC8859-1 is based on this joint ANSI/ECMA proposal. ECMA published its corresponding Standard ECMA-94 inMarch 1985.After this first publication, the work of ECMA TC1 on further coded graphic character sets has led t

10、o the followingresults:i. The present Standard ECMA-121 for a Latin/Hebrew coded graphic set.This 2ndEdition has been developed to keep it fully aligned with the new edition of ISO/IEC 8859-6.ii. The second edition of Standard ECMA-94 comprising four coded graphic character sets for the Latin script

11、,identified as Latin Alphabets No. 1 to No. 4. These alphabets have a number of characters in common, inparticular those allocated to columns 02 to 07. These four Latin Alphabets have been submitted to ISO/IEC andJTC 1 and have become Parts 1 to 4 of ISO/IEC 8859.iii. A series of ECMA Standards for

12、coded graphic character sets comprising those characters of the Latin Alphabetsallocated to columns 02 to 07 and characters of another script for multiple-language applications. These ECMAStandards cover the Arabic, Cyrillic, and Greek scripts. These ECMA Standards ECMA-113, ECMA-114, andECMA-118, r

13、esp., have become Parts 5 to 7, resp., of ISO/IEC 8859.iv. Latin Alphabets No. 5 and No. 6 have been published as ECMA-128 and ECMA-144, resp. They have becomeParts 9 and 10, resp., of ISO/IEC 8859.This ECMA Standard has been adopted as 2ndedition of Standard ECMA-121 by the ECMA General Assembly of

14、December 2000.- i -Table of contents1Scope 12 Conformance 12.1 Conformance of information interchange 12.2 Conformance of devices 12.2.1 Device description 12.2.2 Originating devices 12.2.3 Receiving devices 13 References 14 Definitions 24.1 bi-directional text 24.2 bit combination 24.3 byte 24.4 ch

15、aracter 24.5 code table 24.6 coded character set; code 24.7 coded-character-data-element (CC-data-element) 24.8 directional character properties 24.9 graphic character 24.10 graphic symbol 24.11 implicit directionality 24.12 left-to-right character 34.13 position 34.14 right-to-left character 35 Not

16、ation, code table and names 35.1 Notation 35.2 Layout of the code table 35.3 Names and meanings. 35.3.1 SPACE (SP) 45.3.2 NO-BREAK SPACE (NBSP) 45.3.3 SOFT HYPHEN (SHY) 45.3.4 LEFT-TO-RIGHT MARK (LRM) 45.3.5 RIGHT-TO-LEFT MARK (RLM) 46 Specification of the coded character set 46.1 Characters of the

17、set and their coded representation 46.2 Code table 87 Identification of the character set 97.1 Identification according to ECMA-35 and ECMA-43 97.2 Identification using the ISO International register of coded character sets to be usedwith escape sequences 10Annex A - Coverage of languages 11- ii -An

18、nex B .- Main differences between the first edition and this second edition ofECMA-121 13Annex C - Bi-directional text support 15Annex D - Bibliography 171ScopeThis ECMA Standard specifies a set of 155 coded graphic characters identified as the Latin/Hebrew alphabet.This set of coded graphic charact

19、ers is intended for use in data and text processing applications and also forinformation interchange. The set contains graphic characters used for general purpose applications in typicaloffice environments in at least the following languages:English, Hebrew and Latin.It is not intended for pointed H

20、ebrew.This set of coded graphic characters may be regarded as a version of an 8-bit code according to StandardECMA-35 or Standard ECMA-43 at level 1.This ECMA Standard may not be used with any other ECMA Standards for 8-bit single-byte coded graphiccharacter sets. If coded characters from more than

21、one ECMA Standard are to be used together, by means ofcode extension techniques, the equivalent coded character sets from ISO/IEC 10367 should be used insteadwithin a version of Standard ECMA-43 at level 2 or level 3.The coded characters in this set may be used in conjunction with coded control func

22、tions selected fromECMA-48. However, control functions are not used to create composite graphic symbols from two or moregraphic characters (see clause 6).NOTEThis ECMA Standard is not intended for use with Telematic services defined by ITU-T. If information codedaccording to this ECMA Standard is to

23、 be transferred to such services, it will have to conform to therequirements of those services at the access-point.2 Conformance2.1Conformance of information interchangeA coded-character-data-element (CC-data-element) within coded information for interchange is inconformance with this ECMA Standard

24、if all the coded representations of graphic characters within thatCC-data-element conform to the requirements of clause 6.2.2 Conformance of devicesA device is in conformance with this ECMA Standard if it conforms to the requirements of 2.2.1, and eitheror both of 2.2.2 and 2.2.3. A claim of conform

25、ance shall identify the document which contains thedescription specified in 2.2.1.2.2.1Device descriptionA device that conforms to this ECMA Standard shall be subject of a description that identifies the meansby which the user may supply characters to the device, or may recognize them when they are

26、madeavailable to him, as specified respectively in 2.2.2 and 2.2.3.2.2.2 Originating devicesAn originating device shall allow its user to supply any sequence of characters from those specified inclause 6, and shall be capable of transmitting their coded representations within a CC-data-element.2.2.3

27、 Receiving devicesA receiving device shall be capable of receiving and interpreting any coded representations of charactersthat are within a CC-data-element, and that conform to clause 6, and shall make the correspondingcharacters available to its user in such a way that the user can identify them f

28、rom among those specifiedthere, and can distinguish them from each other.3 ReferencesECMA-6 7-Bit Input/Output Coded Character SetECMA-35 Code Extension Techniques- 2 -ECMA-43 8-Bit Coded Character Set Structure and RulesECMA-48 Control Functions for Coded Character SetsECMA-94 8-Bit Single-Byte Cod

29、ed Graphic Character Sets - Latin Alphabets No. 1 to No. 4ECMA-113 8-Bit Single-Byte Coded Graphic Character Sets - Latin/Cyrillic AlphabetECMA-114 8-Bit Single Byte Coded Graphic Character Sets - Latin/Arabic AlphabetECMA-118 8-Bit Single-Byte Coded Graphic Character Sets - Latin/Greek AlphabetECMA

30、-128 8-Bit Single-Byte Coded Graphic Character Sets - Latin alphabet No. 5ECMA-144 8-Bit Single-Byte Coded Graphic Character Sets - Latin Alphabet No. 64 DefinitionsFor the purpose of this Standard the following definitions apply.4.1bi-directional textA text which may contain strings of characters w

31、ith left-to-right and right-to-left directions.4.2 bit combinationAn ordered set of bits used for the representation of characters.4.3 byteA bit string that is operated upon as a unit.4.4 characterA member of a set of elements used for the organization, control, or representation of data.4.5 code ta

32、bleA table showing the characters allocated to each bit combination in a code.4.6 coded character set; codeA set of unambiguous rules that establishes a character set and the one-to-one relationship between thecharacters of the set and their bit combinations.4.7 coded-character-data-element (CC-data

33、-element)An element of interchanged information that is specified to consist of a sequence of coded representationsof characters, in accordance with one or more identified standards for coded character sets.4.8 directional character propertiesA set of mutually exclusive properties which may qualify

34、the members of a character set. These propertiesare used by algorithms which transform text from processing sequence into presentation sequence.Examples of values for directional character properties are “right-to-left“, “left-to-right“, “digit“, “numericseparator“, “neutral“.4.9 graphic characterA

35、character, other than a control function, that has a visual representation normally hand-written, printed ordisplayed, and that has a coded representation consisting of one or more bit combinations.4.10 graphic symbolA visual representation of a graphic character or of a control function.4.11 implic

36、it directionalityA text presentation method in which the direction is determined by an algorithm. The algorithm is based onthe directional character properties of the character, its position relative to the preceding and followingcharacter and to the primary direction.- 3 -4.12 left-to-right charact

37、erA character specific to a script written from left to right like the Latin script or the Greek script. Typicalexamples are the letters A to Z.4.13 positionThat part of a code table identified by its column and row co-ordinates.4.14 right-to-left characterA character specific to a script written fr

38、om right to left like the Arabic script or the Hebrew script. Typicalexamples are the letters of the Hebrew alphabet.5 Notation, code table and names5.1NotationThe bits of the bit combinations of the 8-bit code are identified by b8, b7, b6, b5, b4, b3, b2and b1, where b8is the highest-order, or most

39、-significant bit and b1is the lowest-order, or least-significant bit.The bit combinations may be interpreted to represent numbers in binary notation by attributing thefollowing weights to the individual bits:Bit b8b7b6b5b4b3b2b1Weight 128 64 32 16 8 4 2 1Using these weights, the bit combinations are

40、 identified by notations of the form xx/yy, where xx and yyare numbers in the range 00 to 15. The correspondence between the notations of the form xx/yy and the bitcombinations consisting of the bits b8to b1is as follows: xx is the number represented by b8, b7, b6and b5where these bits are given the

41、 weights 8, 4, 2, and 1,respectively. yy is the number represented by b4, b3, b2and b1where these bits are given the weights 8, 4, 2, and 1,respectively.The bit combinations are also identified by notations of the form hk, where h and k are numbers in therange 0 to F in hexadecimal notation. The num

42、ber h is the same as the number xx described above, and thenumber k the same as the number yy described above.5.2 Layout of the code tableAn 8-bit code table consists of 256 positions arranged in 16 columns and 16 rows. The columns and therows are numbered 00 to 15. In hexadecimal notation the colum

43、ns and the rows are numbered 0 to F.The code table positions are identified by notations of the form xx/yy, where xx is the column number andyy is the row number. The column and row numbers are shown at the top and left edges of the table,respectively. The code table positions are also identified by

44、 notations of the form hk, where h is the columnnumber and k is the row number in hexadecimal notation. The column and row numbers are shown at thebottom and right edges of the table, respectively.The positions of the code table are in one-to-one correspondence with the bit combinations of the code.

45、 Thenotation of a code table position, of the form xx/yy, or of the form hk, is the same as that of thecorresponding bit combination.5.3 Names and meanings.This ECMA Standard assigns a unique name and a unique identifier to each graphic character. These namesand identifiers have been taken from ISO/

46、IEC 10646-1. This ECMA Standard also specifies an acronym foreach of the characters SPACE, NO-BREAK SPACE, SOFT HYPHEN, LEFT-TO-RIGHT MARK andRIGHT-TO-LEFT-MARK. For acronyms only Latin capital letters A to Z are used. It is intended that theacronyms be retained in all translations of the text.- 4 -

47、Except for SPACE (SP), NO-BREAK SPACE (NBSP), and SOFT HYPHEN (SHY), LEFT-TO-RIGHTMARK (LRM) and RIGHT-TO-LEFT MARK (RLM), this ECMA Standard does not define and does notrestrict the meanings of graphic characters.This ECMA Standard specifies a graphic symbol for each graphic character. This symbol

48、is shown in thecorresponding position of the code table. However, this Standard does not specify a particular style or fontdesign for imaging graphic characters.5.3.1SPACE (SP)A graphic character the visual representation of which consists of the absence of a graphic symbol.5.3.2 NO-BREAK SPACE (NBS

49、P)A graphic character the visual representation of which consists of the absence of a graphic symbol, foruse when a line break is to be prevented in the text as presented.5.3.3 SOFT HYPHEN (SHY)A graphic character that is imaged by a graphic symbol identical with, or similar to, that representingHYPHEN, for use when a line break has been established within a word.5.3.4 LEFT-TO-RIGHT MARK (LRM)A graphic character the visual representation of which consists of the absence of a graphic symbol,which acts like a left-to-right character in a bi-directional text (such as LATIN SMALL LET