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Diffstat (limited to 'lib/asn1/doc/src/asn1_ug.xml')
| -rw-r--r-- | lib/asn1/doc/src/asn1_ug.xml | 104 |
1 files changed, 38 insertions, 66 deletions
diff --git a/lib/asn1/doc/src/asn1_ug.xml b/lib/asn1/doc/src/asn1_ug.xml index 18aa0b1d87..e39b47ff20 100644 --- a/lib/asn1/doc/src/asn1_ug.xml +++ b/lib/asn1/doc/src/asn1_ug.xml @@ -34,23 +34,25 @@ <section> <title>Features</title> - <p>The Asn1 application provides: - </p> + <p>The Asn1 application provides:</p> <list type="bulleted"> <item>An ASN.1 compiler for Erlang, which generates encode and decode functions to be used by Erlang programs sending and receiving ASN.1 specified data.</item> <item>Run-time functions used by the generated code.</item> - <item>The supported encoding rules are: + <item>Support for the following encoding rules: <list> <item> Basic Encoding Rules (<em>BER</em>) </item> <item> - Distinguished Encoding Rules (<em>DER</em>), a specialized form of BER that is used in security-conscious applications. + Distinguished Encoding Rules (<em>DER</em>), a specialized + form of BER that is used in security-conscious + applications. </item> <item> - Packed Encoding Rules (<em>PER</em>) both the aligned and unaligned variant. + Packed Encoding Rules (<em>PER</em>); both the aligned and + unaligned variant. </item> </list> </item> @@ -59,71 +61,41 @@ <section> <title>Overview</title> - <p>ASN.1 (Abstract Syntax Notation 1) is a formal language for describing data structures to be exchanged between distributed computer systems. - The purpose of ASN.1 is to have - a platform and programming language independent notation to express - types using a - standardized set of rules for the transformation of values of - a defined type, into a stream of bytes. This stream of bytes - can then be sent on a communication channel set up by the - lower layers in the stack of communication protocols e.g. - TCP/IP or encapsulated within UDP packets. This way, two - different applications written in two completely different - programming languages running on different computers with - different internal representation of data can exchange - instances of structured data types (instead of exchanging - bytes or bits). This makes programming faster and easier since no code - has to be written to process the transport format of the - data. - </p> - <p>To write a network application which processes ASN.1 encoded - messages, it is prudent and sometimes essential to have a set - of off-line development tools such as an ASN.1 compiler which - can generate the encode and decode logic for the specific ASN.1 - data types. It is also necessary to combine this with some - general language-specific runtime support for ASN.1 encoding and - decoding. - </p> - <p>The ASN.1 compiler must be directed towards a target language - or a set of closely related languages. This manual describes a - compiler which is directed towards the functional language - Erlang. In order to use this compiler, familiarity with the - language Erlang is essential. Therefore, the runtime support for ASN.1 is - also closely related to the language Erlang and - consist of a number of functions, which the - compiler uses. The types in ASN.1 and how to represent - values of those types in Erlang are described in this manual. - </p> - <p>The following document is structured so that the first part describes - how to use ASN.1 compiler, and then there are descriptions of all - the primitive and constructed ASN.1 types and their representation - in Erlang, - </p> + <p>ASN.1 (Abstract Syntax Notation One) is a formal language for + describing data structures to be exchanged between distributed + computer systems. The purpose of ASN.1 is to have a platform + and programming language independent notation to express types + using a standardized set of rules for the transformation of + values of a defined type into a stream of bytes. This stream of + bytes can then be sent on any type of communication + channel. This way, two applications written in different + programming languages running on different computers with + different internal representation of data can exchange instances + of structured data types.</p> </section> <section> <title>Prerequisites</title> - <p>It is assumed that the reader is familiar with the ASN.1 notation - as documented in the standard definition [<cite id="X.680"></cite>] which is - the primary text. It may also be helpful, but not necessary, - to read the standard definitions - [<cite id="X.681"></cite>] [<cite id="X.682"></cite>] [<cite id="X.683"></cite>] - [<cite id="X.690"></cite>] [<cite id="X.691"></cite>]. </p> - <p>A very good book explaining those reference texts is - [<cite id="DUBUISSON"></cite>], free to download at - <url href="http://www.oss.com/asn1/dubuisson.html">http://www.oss.com/asn1/dubuisson.html </url>. + <p>It is assumed that the reader is familiar with the ASN.1 + notation as documented in the standard definition [<cite + id="X.680"></cite>] which is the primary text. It may also be + helpful, but not necessary, to read the standard definitions + [<cite id="X.681"></cite>] [<cite id="X.682"></cite>] [<cite + id="X.683"></cite>] [<cite id="X.690"></cite>] [<cite + id="X.691"></cite>]. </p> + <p>A good book explaining those reference texts is + [<cite id="DUBUISSON"></cite>], which is free to download at + <url href="http://www.oss.com/asn1/dubuisson.html">http://www.oss.com/asn1/dubuisson.html</url>. </p> </section> <section> - <title>Capability</title> + <title>Capabilities</title> <p>This application covers all features of ASN.1 up to the 1997 - edition of the specification. In the 2002 edition of ASN.1 a number of - new features where introduced of which some are supported while - others are not. For example the - ECN (Encoding Control Notation) and XML notation are still - unsupported. Though, the other features of the 2002 edition are - fully or partly supported as shown below:</p> + edition of the specification. In the 2002 edition of ASN.1 a + number of new features were introduced. The following features + of the 2002 edition are fully or partly supported as shown + below:</p> <list type="bulleted"> <item> <p>Decimal notation (e.g., "1.5e3") for REAL values. The @@ -131,7 +103,7 @@ supported.</p> </item> <item> - <p>The RELATIVE-OID type for relative object identifiers are + <p>The RELATIVE-OID type for relative object identifiers is fully supported.</p> </item> <item> @@ -141,16 +113,16 @@ constraint is not a PER-visible constraint.</p> </item> <item> - <p>The subtype constraint by regular expressions (PATTERN) for character string types is parsed when compiling, but no further action is taken. This constraint is not a PER-visible constraint.</p> + <p>The subtype constraint by regular expressions (PATTERN) + for character string types is parsed when compiling, but no + further action is taken. This constraint is not a + PER-visible constraint.</p> </item> <item> <p>Multiple-line comments as in C, <c>/* ... */</c>, are supported.</p> </item> </list> - <p>It should also be added here that the encoding formats - supported are <em>BER</em>, <em>DER</em>, <em>PER aligned - basic</em> variant and <em>PER unaligned basic</em> variant.</p> </section> </section> |