ISO/IEC 8824-3:1995

Information technology — Abstract Syntax Notation One (ASN.1): Constraint specification

Technologies de l'information — Notation de syntaxe abstraite numéro un (ASN.1): Spécification des contraintes

General Information

• Status: Withdrawn
• Publication Date: 11-Oct-1995
• Withdrawal Date: 11-Oct-1995
• ICS: 35.100.60 - Presentation layer
• Technical Committee: ISO/IEC JTC 1/SC 6 - Telecommunications and information exchange between systems
• Drafting Committee: ISO/IEC JTC 1/SC 6 - Telecommunications and information exchange between systems
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 09-Dec-1999

Relations

• Revised: ISO/IEC 8824-3:1998 - Information technology — Abstract Syntax Notation One (ASN.1): Constraint specification — Part 3:
• Effective Date: 15-Apr-2008

Standards Content (Sample)

INTERNATIONAL
ISO/IEC
STANDARD
8824-3
First edition
1995-l o-1 5
Information technology - Abstract Syntax
Notation One (ASN.l): Constraint
specification
Technologies de I’informa tion - Notation de syntaxe abstraite numkro I
(ASN. 1): Spkifications pour con train tes
Reference number
&O/l EC 8824-3: 1995(E)

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ISO/IEC 8824-3: 1995(E)
CONTENTS
Page
1
1 .
Scope
1
2 Normative references .
1
........................................................................
2.1 Identical Recommendations I International Standards
1
3 Definitions .
1
............................................................................................................
3.1 Specification of basic notation
1
Information object specification .
3.2
1
33 Parameterization of ASN. 1 specification .
1
314 Additional definitions .
2
.................................................................................................................................................
Abbreviations
2
Convention .
2
Notation .
2
. Constraint .
61
2
7 ASN. 1 items .
2
...................................................................................................................
7.1 Additional keyword items
3
.....................................................................................................................
8 General constraint specification
3
9 User-defined constraints .
3
..............................................................................................................................................
9.4 Example
......................................................................... 4
10 Table constraints, including component relation constraints
7
................................................................................................................
Annex A - Constraining instance-of types
7
..............................................................................................................................................
A.4 Example
8
Annex B - Summary of the notation .
0 ISOLIEC 1995
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ISO/IEC Copyright Office l Case postale 56 l CH- 12 11 Geneve 20 l Switzerland
Printed in Switzerland
ii

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0 ISO/IEC ISO/IEC 8824-3: 1995(E)
Foreword
IS0 (the International Organization for Standardization) and IEC (the Inter-
national Electrotechnical Commission) form the specialized system for worldwide
standardization. National bodies that are members of IS0 or IEC participate in the
development of International Standards through technical committees established
by the respective organization to deal with particular fields of technical activity.
IS0 and IEC technical committees collaborate in fields of mutual interest. Other
international organizations, governmental and non-governmental, in liaison with
IS0 and IEC, also take part in the work.
In the field of information technology, IS0 and IEC have established a joint
technical committee, ISO/IEC JTC 1. Draft International Standards adopted by the
joint technical committee are circulated to national bodies for voting. Publication
as an International Standard requires approval by at least 75 % of the national
bodies casting a vote.
International Standard ISO/IEC 8824-3 was prepared by Joint Technical
Committee ISO/IEC JTC 1, Information technology, Subcommittee SC 21, Open
systems interconnection, data management and open distributed processing, in
collaboration with ITU-T. The identical text is published as ITU-T
Recommendation X.682.
This is a revision of ISO/IEC 8824: 1990.
ISO/IEC 8824: 1995 consists of the following parts, under the general title
Information technology -Abstract Syntax Notation One (ASN. I):
- Part 1: Specification of basic notation
Part 2: Information object specification
Part 3: Constraint specification
- Part 4: Parameterization of ASN. I specifications
Annex A forms an integral part of this part of ISO/IEC 8824: 1995. Annex B is for
information only.
. . .
111

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ISO/IEC 8824=3:1995(E) 0 ISO/IEC
Application designers require a notation to define a structured data type to convey their semantics. This is provided in
ITU-T Rec. X.680 I ISO/IEC 8824-l and ITU-T Rec. X.681 I ISO/IEC 8824-2. A notation is also required to further
constrain the values that can appear. Examples of such constraints are restricting the range of some component(s), or
using a specified information object set to constrain an “ObjectClassFieldType” component, or using the “AtNotation” to
specify a relation between components.
This Recommendation I International Standard provides the notation for the general case of constraint specification.
NOTE 1 - For historical reasons the special case of a “subtype constraint”
is specified in ITU-T Rec. X.680 I
ISOLIEC 8824- 1.
Constraint notation can appear (in parentheses) after any use of the syntactic construct “Type”, and the purpose of this
Recommendation 1 International Standard is to specify the general case of what goes in the parentheses.
NOTE 2 - Multiple constraints (each inside its own parentheses) can be applied to the same “Type”, as the result of
constraining a “Type” is itself formally a “Type” construct.
When a constraint is applied to the textually outermost use of a “Type” construct, it results in the creation of a new type
which is a subtype of the original (parent) type.
A subtype of a parent type can itself be used in defining other subtypes of the same. parent type in other uses of the
constraint notation. Thus the subset of values constituting a subtype can be defined either by limiting the range of the
parent type, or by specifying the subtype as a union of sets of values.
NOTE 3 - The “ValueSet” notation specified in ITU-T Rec. X.680 I ISO/IEC 8824-l) subclause 13.5, provides a further
means of specifying a subtype.
Constraints may also be used to produce a subtype of a parent type (as described above) when the notation is embedded
within another type. However, some “component relation” constraints are textually included following a “Type” (within
a set or sequence type definition), but are not used to restrict the set of possible values of the “Type” which they follow
(the referencing component). Rather, they specify a relation between the value of the referencing component and the
value of one or more other “Type”s in the same set or sequence type (called the referenced components).
Component relation constraints can be seen as subtyping the sequence within which they are embedded, but not
type
necessarily the referencing type.
A constraint on an “ObjectClassFieldType” component can be applied by restricting the type or values in the component
by using an information object set. Such constraints are called table constraints, since they are specified in terms of the
“associated table” of the object set. The component relation constraints defined in this Recommendation I International
Standard are a special case of table constraints.
Finally, a “Type” may be subtyped by specifying the set of values in the subtype by human-readable text. Such a
constraint is called a user-defined constraint. For example, a user-defined constraint can be specified to constrain a BIT
STRING to the set of values produced by the encryption of a value of a specified ASN.l type.
It is the purpose of this Recommendation I International Standard to provide the notation to be used for specifying table
constraints), and user-defined constraints.
constraints (including component relation
NOTE 4 - In general, full support for the specification of constraints in a flexible way (particularly component relation
constraints, subtyping constraints, and user-defined constraints with a formally defined body) would require notation with a power
comparable to that of programming languages. Such power can only be sensibly provided by the establishment of links from the
ASN. 1 notation into some other defined computer language. This version of this Recommendation I International Standard does not
provide such links, and hence supports only a small number of constraining mechanisms.

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0 ISO/IEC ISO/IEC 8824-3: 1995(E)
While the embedding of notation defining constraints (subtypes and relationships) will frequently be the most
convenient form of specification (particularly for the simple subtyping of primitive components of structures), separate
(external) specification will sometimes be preferred, particularly where the constraints are being imposed by a separate
group from that which defined the basic protocol.
NOTE 5 - The parameterization defined in ITU-T Rec. X.683 I ISO/IEC 8824-4 is specifically designed to enable a piece
of ASN.l specification (and in particular, a constraint) to be parameterized, allowing the actual constraint to be imposed by some
other group that provides actual parameters for the parameterized construct.
The notations for specification supported here are:
constraint
user-defined constraints (see clause 9);
- table constraints, including component relation constraints between two components which are
carrying values related to an information object, defined using the notation of ITU-T Rec. X.681 1
ISO/IEC 8824-2 (see clause 10).
The application of table constraints to the “InstanceOfType” construct of ITU-T Rec. X.681 I ISO/IEC 8824-2, Annex C,
is specified in Annex A of this Recommendation I International Standard.
V

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ISO/IEC 8824-3 : 1995 (E)
INTERNATIONAL STANDARD
ITU-T RECOMMENDATION
INFORMATION TECHNOLOGY -
ABSTRACT SYNTAX NOTATION ONE (ASN.1):
CONSTRAINT SPECIFICATION
1
Scope
This Recommendation I International Standard is part of Abstract Syntax Notation One (ASN.1) and provides notation
for specifying user-defined constraints and table constraints.
2 Normative references
The following Recommendations and International Standards contain provisions which, through reference in this text,
constitute provisions of this Recommendation I International Standard. At the time of publication, the editions indicated
were valid. All Recommendations and Standards are subject to revision, and parties to agreements based on this
Recommendation I International Standard are encouraged to investigate the possibility of applying the most recent
editions of the Recommendations and Standards listed below. Members of IEC and IS0 maintain registers of currently
valid International Standards. The Telecommunications Standardization Bureau of the ITU maintains a list of currently
valid ITU-T Recommendations.
21 . Identical Recommendations I International Standards
-
ITU-T Recommendation X.680 (1994) I ISO/IEC 8824- 1: 1995, Znformation technology - Abstract Syntax
Notation One (ASN.1): Specification of basic notation.
-
ITU-T Recommendation X.68 1 (1994) I ISO/IEC 8824-2: 1995, Information technology - Abstract Syntax
Notation One (ASN. I): Information object specification.
- ITU-T Recommendation X.683 (1994) I ISO/IEC 8824-4: 1995, Information technology - Abstract Syntax
Notation One (ASN. I ): Parameterization of ASN. I specifications.
Definitions
3
For the purposes of this Recommendation I International Standard, the following definitions apply:
l Specification of basic notation
31
This Recommendation I International Standard uses the terms defined in ITU-T Rec. X.680 I ISO/IEC 8824-l.
32 . Information object specification
This Recommendation I International Standard uses the terms defined in ITU-T Rec. X.681 I ISO/IEC 8824-2.
33 l Parameterization of ASN.1 specification
This Recommendation I International Standard uses the following term defined in ITU-T Rec. X.683 I ISO/IEC 8824-4:
-
parameterized type.
34 . Additional definitions
3.4.1 component relation constraint: A constraint on the values of a set type or sequence type which is textually
associated with one of the component types (the referencing component) of the set type or sequence type, and which
specifies the relationship between the value of that component and the values of one or more other components (the
referenced components).
ITU-T Rec. X.682 (1994 E)

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ISOAEC 8824-3 : 1995 (E)
constrained type: The innermost “Type” which contains the referencing componen .t and all of the referenced
3.4.2
components of some component relation constraint.
3.4.3 constraining set: The information object set referenced in some component relation constraint.
3.4.4 constraining table: The associated table (see ITU-T Rec. X.68 1 I ISO/IEC 8824-2, clause 13) corresponding
to a constraining set.
3.4.5 referenced component: A component of a set type or sequence type identified in a component relation
constraint.
3.4.6 referencing component: A component of a set type or sequence type which has an associated component
relation constraint.
which contain, in the appropriate columns, the values of all
3.4.7 selected rows: Those rows of a constraining table
of the referenced components.
constraint: A constraint applied to an object class field type which demands that its values conform to
3.4.8 table
the contents of the appropri ate column of some table.
3.4.9 user-defined constraint: A constraint which requires a more complicated statement than can be
accommodated by the other forms of constraint, and which must therefore involve specification by some means outside
of ASN. 1.
4 Abbreviations
ASN.1 Abstract Syntax Notation One
5
Convention
This Recommendation I International Standard employs the notational convention defined in ITU-T Rec. X.680 I
ISOAEC 8824-1, clause 5.
6 Notation
This clause summarizes the notation defined in this Recommendation I International Standard.
61 . Constraint
“ConstraintSpec” (see ITU-T Rec. X.680 I
The following notation which can be used as an alternative for
ISO/IEC 8824-1, subclause 42.5) is defined in this Recommendation I International Standard:
-
Generalconstraint (see 8.1).
7 ASN.1 items
In addition to the ASN.1 items specified in ITU-T Rec. X.680 I ISO/IEC 8824-1, clause 9, this Recommendation I
International Standard makes use of the ASN.l items specified in the following subclauses. The general rules applicable
to these items are as defined in ITU-T Rec. X.680 I ISO/IEC 8824-1, subclause 9.1. These new ASN. 1 items make use of
the ASN. 1 character set, as specified in ITU-T Rec. X.680 I ISO/IEC 8824-l) clause 8.
71 0 Additional keyword items
The names CONSTRAINED and BY are listed in ITU-T Rec. X.680 I ISO/IEC 8824-l) subclause 9.16 as reserved
words.
2
ITU-T Rec. X.682 (1994 E)

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ISO/IEC 8824-3 : 1995 (E)
8 General constraint specification
81 . The notation for a “Generalconstraint” is as follows:
GeneralConstraint ::=
UserDefinedConstraint I
TableConstraint
82 . The various possibilities for specification of the constraint are defined as follows:
“UserDefinedConstraint”, in clause 9;
a>
“TableConstraint”, in clause 10.
W
9 User-defined constraints
NOTES
This form of constraint specification can be regarded as a special form of ASN.1
...