This document describes the changes made to old versions of the asn1 application.

R3B02 (Asn1 1.0.2)

Fixed errors and malfunctions

• The decoding of a BER encoded SEQUENCE with optional component of type SEQUENCE (also with optional components) could result in an error or wrong result if the tags are equal.
  Own Id: OTP-2226
• The encoding of (PER) SEQUENCE with extensionmark was wrong. This is now corrected.
  Own Id: OTP-2349

R3A (Asn1 0.9)

Fixed errors and malfunctions

• The asn1 compiler now detects the use of an implicit tag before CHOICE as an error (in accordance with the standard)
  Own Id: OTP-1844
• An OPTIONAL CHOICE embedded in SEQUENCE when BER coding caused an error when generating decode code. This is now corrected.
  Own Id: OTP-1857
  Aux Id: OTP-1848

1 ASN1 0.8.1

This is the first release of the ASN1 application. This version is released for beta-testing. Some functionality will be added until the 1.0 version is released. See the release notes for the latest version for the exact details about new features. A list of missing features and restrictions can be found in the chapter below.

1.1 Missing features and other restrictions

• The encoding rules BER and PER (aligned) is supported. PER (unaligned) IS NOT SUPPORTED.
  
• NOT SUPPORTED types ANY and ANY DEFINED BY (is not in the standard any more).
  
• NOT SUPPORTED types EXTERNAL and EMBEDDED-PDV.
  
• NOT SUPPORTED type REAL (planned to be implemented).
  
• The code generation support for value definitions in the ASN.1 notation is very limited (planned to be enhanced).
  
• The support for constraints is limited to:
  
  • SizeConstraint SIZE(X)
    
  • SingleValue (1)
    
  • ValueRange (X..Y)
    
  • PermittedAlpabet FROM (but not for BMPString and UniversalString when generating PER).
    
  Complex expressions in constraints is not supported (planned to be extended).
  
• The current version of the compiler has very limited error checking:
  
  • Stops at first syntax error.
    
  • Does not stop when a reference to an undefined type is found , but prints an error message. Compilation of the generated Erlang module will then fail.
    
  • A whole number of other semantical controls is currently missing. This means that the compiler will give little or bad help to detect what's wrong with an ASN.1 specification, but will mostly work very well when the ASN.1 specification is correct.
    
• The maximum INTEGER supported in this version is a signed 64 bit integer. This limitation is probably quite reasonable. (Planned to be extended).
  
• Only AUTOMATIC TAGS supported for PER.
  
• Only EXPLICIT and IMPLICIT TAGS supported for BER.
  
• The compiler supports decoding of BER-data with indefinite length but it is not possible to produce data with indefinite length with the encoder.