This document describes the changes made to the asn1 system from version to version. The intention of this document is to list all incompatibilities as well as all enhancements and bugfixes for every release of the asn1 application. Each release of asn1 thus constitutes one section in this document. The title of each section is the version number of asn1.

## 1 Asn1 1.4.3.1

### 1.1 Fixed Bugs and Malfunctions

- The {internal_error,...,{ unrecognized_type,...}} error occuring for a SET type when compiling with options [ber_bin,optimize,der] is now corrected.
  Own Id: OTP-4866
- False encode of BIT STRING in PER (per_bin,optimize) is fixed. The error occured when there was a type like BIT STRING (SIZE(C)) and C > 16.
  Own Id: OTP-4869

## 2 Asn1 1.4.3

### 2.1 Fixed errors and malfunctions

- Functionality to handle parameterized object sets have been added.
  Own Id: OTP-4832
- Bug causing duplicated fuction definitions using exclusive decode is removed.
  Own Id: OTP-4833)
- The race condition when loading asn1 driver is solved.
  Own Id: OTP-4835

### 2.2 Improvements and new features

- A specialized decode, selective decode is now available. It decodes a chosen internal sub-type of a constructed type.
  Own Id: OTP-4856)

## 3 Asn1 1.4.2.2

### 3.1 Fixed errors and malfunctions

- Release of Asn1 1.4.2.1 on R7B, The functionality is the same, but the layer between the driver and the asn1 erlang code is different.

## 4 Asn1 1.4.2.1

### 4.1 Fixed errors and malfunctions

- ObjectDescriptor does now work as part of a sequence, set or choice.
  Own Id: OTP-4773
- When a SEQUENCE that have extension mark was decoded inside a SEQUENCE OF it could cause decode error due to a failure in restbytes2. It is now corrected.
  Own Id: OTP-4791)
- Now the bug is fixed that caused the compiler crash on an untaged optional open type.
  Own Id: OTP-4792
- The earlier exit caused by bad indata is now fixed so it will rreturn an {error,Reason} tuple.
  Own Id: OTP-4797
- Open type encoded with indefinite length is now correct decoded.
  Own Id: OTP-4798
- Now is absent optional open types handled correctly.
  Own Id: OTP-4799
- Now is the necessary functions available for sorting in run-time of SET and SET OF components.
  Own Id: OTP-4809

## 5 Asn1 1.4.2

### 5.1 Fixed errors and malfunctions

- When a component in a SEQUENCE is a CHOICE (or reference to a CHOICE) and the SEQUENCE's component and one of the alternatives in the CHOICE have identical names, an error may occur if one doesn't use the 'optimized' versions of the compiler. In the older versions (ber, ber_bin, per, per_bin) one could optionally apply a value of a component as {ComponentName,Value}, and the generated code chooses the second element of the tuple. However, a value of a CHOICE must be applied as a tuple: {AlternativeName,Value}. Thus, in the rare case described above and if the value to the SEQUENCE's component is not in a tuple notation the {AlternativeName,Value} will be peeled off in the SEQUENCE and the value fed to the CHOICE will only be the Value part of {AlternativeName,Value}, and the encoder crashes. The best way to avoid this is to use the optimized version of the compiler where the unnecessary tuple notation {ComponentName,Value} no longer is allowed. Since it isn't possible to solve this bug in the compiler.
  Own Id: OTP-4693

### 5.2 Improvements and new features

- Exclusive decode is enabled by a compiler option and a configuration file. It makes it possible to leave parts of an ASN.1 encoded message undecoded.
  Own Id: OTP-4744

## 6 Asn1 1.4.1.1

### 6.1 Fixed errors and malfunctions

- The documentation about how extensibility is handled is now corrected.
  Own Id: OTP-4663
- Function in object now calls the exported function
  Own Id: OTP-4665
- Now is tags for ObjectClassFieldType analyzed correctly.
  Own Id: OTP-4666

## 7 Asn1 1.4.1

### 7.1 Fixed errors and malfunctions

- Now is the Default value for an ENUMERATED returned as the name from the NamedList when decoding.
  Own Id: OTP-4633
- It was an internal failure when permitted alphabet constraint existed together with for instance a size constraint. E.g. when a referenced type is constrained by a size constraint and the defined type in turn is constrained by a permitted alphabet constraint.
  Own Id: OTP-4559
- Record is generated in hrl file for a CHOICE with extension mark that has an internal SEQUENCE/SET definition.
  Own Id: OTP-4560
- Now is the length of a SEQUENCE/SET OF correctly encoded/decoded (PER).
  Own Id: OTP-4590
- The problem with unordered decoded terms when a component is a ObjectClassFieldType has been solved.
  Own Id: OTP-4591

### 7.2 Improvements and new features

- More complex definitions with TableConstraints where the SimpleTable and ComponentRelation are on different levels is now fully supported.
  Own Id: OTP-4631

## 8 Asn1 1.4

### 8.1 Fixed errors and malfunctions

### 8.2 Improvements and new features

- Each generated .erl file have now a function info/0 that returns information about the used compiler version and options.
  Own Id: OTP-4373
- When compiling an ASN.1 module the compiler generates an Erlang module that is compiled by the Erlang compiler. Earlier it was not possible to add options to the final step, the Erlang compilation. By adding any option that is not recognized as a specific ASN.1 option it will be passed to the final step like: erlc +debug_info Mymodule.asn or asn1ct:compile('Mymodule',[debug_info]).
  Own Id: OTP-4491
- Earlier one couldn't multi file compile modules that had different tagdefaul, which now is possible. Equal Type/Value names in different modules are resolved by renaming (concatenate type name and module name): If two types with the same name T exist in module A and module B they will get the new names TA and TB.
  (Own Id: OTP-4492)
  Aux Id: OTP-3983
- BER: Encode/decode of data have been significantly improved. By use of the compiler options ber_bin and optimize, optimized code will be generated and the optimized run-time module will be used.
  Own Id: OTP-4493

## 9 Asn1 1.3.3.1

### 9.1 Fixed errors and malfunctions

- Proper length encoding and padding implemented for a BIT STRING with NamedNumberList and size constraint as value range. This functionality didn't work in the rare occasion when the NamedNumberList is shorter than the lower bound of the constraint.As in this example: TestS ::= BIT STRING {a (0),b (1)} (SIZE (3..8))
  (Own Id: OTP-4353)
- Bug in compiler, when an OBJECT IDENTIFIER value consisting of two identifiers (Defined values or Name form identifiers) was falsely interpreted causing a compiling error is now corrected.
  (Own Id: OTP-4354)
- Internal error in check phase that caused crash on ObjectClassFieldType in ber_bin is corrected.
  (Own Id: OTP-4390)
- Tags for open types are handled according to x.680 30.6c, i.e. open types shall not be tagged IMPLICIT.
  (Own Id: OTP-4395)
  (Aux Id: OTP-4390)

## 10 Asn1 1.3.3

### 10.1 Fixed errors and malfunctions

- Now gives the compiler an apropriate error report when exported undefined types are detected.
  (Own Id: OTP-4129)
- The type ObjectDescriptor is now supported, previously the implementation of encode/decode for this rarely used type was incomplete.
  (Own Id: OTP-4161)
  (Aux Id: seq7165)
- In case of per and compact_bit_string the rightmost byte were erronous truncated when the rightmost bits of that byte were zeros. This is now corrected.
  (Own Id: OTP-4200)
- Bad match of returnvalue from decode_length in skipvalue/3 has now been fixed.
  (Own Id: OTP-4232)
- Now is decode of ENUMERATED handled correctly, when tagged EXPLICIT.
  (Own Id: OTP-4234)
- The compiler now parses and handles the ValueFromObject construct.
  (Own Id: OTP-4242)
- Now does the compiler handle the case when the object set in simple table and componentrelation constraints is of a CLASS without a UNIQUE field. In this case is the octets, which is assumed to be encoded, encoded as an open type.
  (Own Id: OTP-4248)
  (Aux Id: OTP-4242)
- Compiler handles objects in AdditionalElementSetSpec in ObjectSetSpec, i.e. the objects that are referred to after the ellipses in an object set.
  (Own Id: OTP-4275)
- Now are values with a component of type CHOICE encoded with indefinite length correctly decoded.
  (Own Id: OTP-4358)

### 10.2 Improvements and new features

- The language constructs (from the old 1988 standard) ANY and ANY DEFINED BY are now implemented.
  (Own Id: OTP-2741)
  (Aux Id: seq 1188)
- Now it is checked in run-time if a OBJECT IDENTIFIER value is unvalid
  (Own Id: OTP-4235)
- The ASN.1 types EXTERNAL,EMBEDDED PDV and CHARACTER STRING now have full support in the compiler.
  (Own Id: OTP-4247)
- A driver in C does the final job (complete) of the PER encoding when files are compiled with per_bin and optimize flags. It gives significant faster encoding for PER.
  (Own Id: OTP-4355)
- Encode and decode of PER encoding has been made faster by moving analysis done in run-time to compile-time. These optimizations are available by compiling ASN.1 files with options per_bin and optimize.
  (Own Id: OTP-4381)
  (Aux Id: OTP-4355)

## 11 Asn1 1.3.2

### 11.1 Fixed errors and malfunctions

- Now does the compiler check values (including referenced values), and formats the value so it is suitable to use as input to encoding functions.
  (Own Id: OTP-3277)
  (Aux Id: OTP-4103)
- Unnecessary external function calls in generated code are now generated as internal function calls.
  (Own Id: OTP-4073)

### 11.2 Improvements and new features

- Now is Information Objects supported in BER encoding.
  (Own Id: OTP-3980)
  (Aux Id: OTP-3979 OTP-3978)
- PER: A new option per_bin is now supported. When used the generated encode/decode functions use binaries and the bit syntax to get better performance than the old per variant which used lists. All values input to encode and returned from decode are compatible between per and per_bin except for open types which are represented as binaries with per_bin and octet lists with per. We recommend that you use per_bin instead of per from now on, the use of binaries will be the default in coming versions and all improvements and optimizations for PER will be concentrated to that solution.
  (Own Id: OTP-4094)
- Support for DER implemented. Used by flag +der when compiling. Include the full BER encoding plus: sorting of SET components, sorting of encoded elements in SET OF, full check of default values in SET and SEQUENCE. See new documentation on DER in user_guide sections 1.3.1; 1.4.11; 1.4.12; 1.4.14; 1.4.16 and 1.10, in the reference manual for asn1ct.
  (Own Id: OTP-4103)

## 12 Asn1 1.3.1

### 12.1 Fixed errors and malfunctions

- Do not generate record in .hrl file for SET types
  Own Id: OTP-4025
- Fixed internal error when using BIT STRINGs with Named Number List in combination with compact_bit_string and ber_bin options.
  Own Id: OTP-4026
  Aux Id: OTP-3982
- The atom 'com' can now be used in ENUMERATED as an EnumerationItem.
  Own Id: OTP-4037
  Aux Id: Seq 7036
- ber: Now it is possible (again) to encode data format "{Type,Value}" in a SEQUENCE OF RequestParameter, when RequestParameter is of type ENUMERATED. The {Type,Value} notation is not recommended for use, it is redundant and exist only for very ancient backwards compatibility reasons. The "feature" might be removed in forthcoming versions.
  Own Id: OTP-4057
  Aux Id: Seq 7066
- A bug in the parser, that caused failure on COMPONENTS OF is now removed.
  Own Id: OTP-4058

## 13 Asn1 1.3

### 13.1 Known problems

- The compiler will now check that a value referenced by name does exist.
  Own Id: OTP-3277
- BER:Decode of a type T ::= SEQUENCE OF C fails if C is encoded with indefinite length. This is know corrected.
  Own Id: OTP-3811
  Aux Id: seq5040

### 13.2 Fixed errors and malfunctions

- The new parser handles imports when one import ends with FROM, a modulename and a reference to a objectidentifier followed by imports from other modules.
  Own Id: OTP-3463
- The compiler did not check that a name mentioned as EXPORTED actually is defined within the module. This is now corrected.
  Own Id: OTP-3659
- Removed bug caused by use of nested indefinite length
  Own Id: OTP-3994

### 13.3 Improvements and new features

- Now supporting most common use of parameterization according to X.683
  (Own Id: OTP-3978)
- PER: Now supporting most common use of Information Objects according to X.681. A new parser has been implemented. The error messages due to syntax errors are slightly different than previous. TableConstraint part of X.682 now also supported.
  Own Id: OTP-3979
- New compiler option added: ber_bin. The compiler generates code with new bit syntax. Run time functions uses bit syntax when feasible. Higher encoding/decoding performance in most cases. Se also comments for Asn1 1.2.9.3.
  Own Id: OTP-3981
- A more compact format of BIT STRING in Erlang is now available by use of the compiler option compact_bit_string. It is much faster when large BIT STRINGs are used.
  Own Id: OTP-3982
- Now possible to merge many ASN.1 input files to one Erlang file by use of a configuration file that lists the ASN.1 files.
  Own Id: OTP-3983
- New documentation in User's Guide in section:
  3.1: New compile-time functions and options are described.
  4.6: New compact format of BIT STRING is described.
  4.8: Additional comments on character strings.
  7: New section describing ASN.1 Information Objects.
  8: New section describing Parameterization.
  Reference Manual/asn1ct New compile options are described.
  Own Id: OTP-3984
  Aux Id: OTP-3978, OTP-3979, OTP-3981, OTP-3982, OTP-3983
- Added the functionality to invoke ASN1Mod:encode (and decode).
  Own Id: OTP-3985
- Performance improvements by removing not necessary use of apply when calling asn1rt:encode. Also other general improvements.
  Own Id: OTP-3988

## 14 Asn1 1.2.9.6

### 14.1 Known problems

- The compiler does not check that an exported name actually exists in the ASN.1 module.
  Own Id: OTP-3659
- The compiler does not check that a value referenced by name does exist.
  Own Id: OTP-3277
- BER: The compiler does not take the extensions into account when checking if the tags are unique in a SEQUENCE or SET.
  Own Id: OTP-3304

### 14.2 Fixed errors and malfunctions

- PER: Trailing zeroes in a BIT STRING declared without named bits should not be removed in the encodings.
  Own Id: OTP-3830

## 15 Asn1 1.2.9.5

### 15.1 Known problems

Same as for 1.2.9.3.

### 15.2 Fixed errors and malfunctions

- PER: Constraints are not propagated when types are referring to each other. Example:

                      TBCD-STRING ::= OCTET STRING

                      LAI ::= TBCD-STRING (SIZE(3))

  The size constraint is not passed on during encode,decode resulting in wrong encoding for PER , it is coded with a length determinant which should not be there when the length is fixed. For BER this does not matter because the constraints does not affect the encodings.
  Own Id: OTP-3713
- The generated code gets wrong if there are several ENUMERATED fields in a SEQUENCE or SET, this is now corrected.
  Own Id: OTP-3796
- BER:Decode of a type T ::= SEQUENCE OF C fails if C is encoded with indefinite length. This is know corrected.
  Own Id: OTP-3811

## 16 Asn1 1.2.9.3

### 16.1 Known problems

- The compiler does not check that an exported name actually exists in the ASN.1 module.
  Own Id: OTP-3659
- The compiler does not check that a value referenced by name does exist.
  Own Id: OTP-3277
- BER: The compiler does not take the extensions into account when checking if the tags are unique in a SEQUENCE or SET.
  Own Id: OTP-3304

### 16.2 Fixed errors and malfunctions

- This version supports soft upgrade from versions 1.2.6 1.2.7.
- In an ENUMERATED type like this:

                      T ::= ENUMERATED { blue, green}

  The symbols was encoded/decoded with the wrong values, i.e in reverse order. This is now corrected.
  Own Id: OTP-3700
- PER: OCTET STRING with Size constrained to a single value i.e fixed size was treated wrong during encode and decode. This is now corrected.
  Own Id: OTP-3701

### 16.3 Improvements and new features

- There is now a new compiler option ber_bin available that can be used to generate encode/decode functions for BER that uses the new "bit-syntax" to make the functions more efficient. The ber_bin option is used as an alternative to the ber and per options.
  The encode function then produces a possibly nested list of binaries and integer lists. The decode function does in this case require a single binary as input instead of a list. The modules generated with this option require that you have an R7A or later system, otherwise they will not compile and the runtime module asn1rt_ber_bin can not be executed.
  The ber_bin option is not officially supported in this version (will be in a later version) but is provided for those who want to try it. It should be significantly faster at decode and is slightly faster at encode. Exactly how performance differs between this binary approach and the list approach depends highly on the type of input. Another thing worth noting is that both approaches still have a lot of solutions in common which can be improved a lot to gain even better performance.

## 17 Asn1 1.2.9.2

### 17.1 Fixed errors and malfunctions

- BER: Encode/decode of extension components did not work properly. This is now corrected.
  Own Id: OTP-3395
  Aux Id:
  PER:The encode/decode of NULL as an open type has been corrected. An open type must always have a length of at least 1 byte even if the contained value (e.g NULL) encodes to nothing.
  Own Id: OTP-3496
  Aux Id:
- BER:In the current implementation extension components of a SEQUENCE are required to be present when they are specified as mandatory. This is an error, all extension components are "optional" even if they are not specified to have the OPTIONAL or DEFAULT property. This is now corrected.
  Own Id: OTP-3278

### 17.2 Improvements and new features

- The ASN.1 language feature COMPONENTS OF is now implemented.
  Own Id: OTP-2515
- The encoding and decoding of ENUMERATED and INTEGER with NamedNumbers is made more efficient and thus faster in runtime.
  Own Id: OTP-3464
  Aux Id:
- Added support for encode/decode of open type which is constrained to a specific type. Previously the value of an open type had to be a list of octets, but now the Erlang representation of the specific type used in the constraint is used both as input to encode and as output from decode.
  Own Id: OTP-3569
  Aux Id:
- PER: GeneralString, GraphicalString etc. i.e all strings that are not so called "known-multiplier character string types" are now supported by the runtime encode/decode functions.
  Own Id: OTP-3573
  Aux Id:

## 18 Asn1 1.2.6

### 18.1 Known problems

- The ASN.1 language feature COMPONENTS OF is not implemented.
  Own Id: OTP-2515
- The compiler does not check that a value referenced by name does exist.
  Own Id: OTP-3277
- BER:In the current implementation extension components of a SEQUENCE are required to be present when they are specified as mandatory. This is an error, all extension components are "optional" even if they are not specified to have the OPTIONAL or DEFAULT property.
  Own Id: OTP-3278
- BER: The compiler does not take the extensions into account when checking if the tags are unique in a SEQUENCE or SET.
  Own Id: OTP-3304

### 18.2 Fixed errors and malfunctions

- This version supports soft upgrade from versions 1.1.1, 1.1.5 and 1.1.6. Two new runtime modules asn1rt_ber_v1 and asn1rt_per_v1 are delivered together with the old ones. This makes it possible to continue running applications with modules generated with the previous version of the asn1 compiler while modules generated by this version will use the new runtime modules. Note that it is only advice-able to continue running old generates if they are working perfectly and have no need for the corrections made in this version of the asn1 application.
- BER: SEQUENCEs encoded with indefinite length was not correctly decoded. This in now corrected.
  Own Id: OTP-3352
  Aux Id: Seq 4100

## 19 Asn1 1.2.4

### 19.1 Fixed errors and malfunctions

- The compiler now detects multiple definitions of values and types and reports this as an error. Previously this was detected when the generated Erlang module was compiled.
  Own Id: OTP-3105
- BER: An error regarding encoding of ENUMERATED present in asn1-1.1.1 is corrected. The new version 1.1.2 of asn1 containing this correction is delivered as a "patch".
  Own Id: OTP-3169
- BER: Decoding of SEQUENCE OF and SET OF with indefinite length is corrected. The correction was first delivered in version 1.1.2.
  Own Id: OTP-3170
- BER: Encoding and decoding of ENUMERATED with extensionmark "..." did not work (crashed with a runtime error). This has now been corrected. If an unknown enumerated value is decoded (for an extensible enumerated type) it is returned as {asn1_enum,Value} where Value is an integer. Enumerated values in this format are also accepted by the encoder. ASN.1 modules containing ENUMERATED with extensionmark should be recompiled with the corrected version of the compiler. The BER runtime functions are also corrected. Note that this correction has already been delivered as a bugfix for R4B (OTP-2951).
  Own Id: OTP-3202
  Aux Id: Seq3745
- BER: The primitive/constructed bit in the tag byte of an encoding is not correct when it comes to user defined tags. For example in

       T ::= [2] SEQUENCE { a BOOLEAN}

  the tag 2 does not get the constructed bit set which it should. This is now corrected.
  Own Id: OTP-3241
- The decoder can now detect if there are unexpected bytes remaining when all components of a sequence are decoded. The decoder will then return {error,{asn1{unexpected,Bytes}}}
  Own Id: OTP-3270
- Values of type OBJECT IDENTIFIER was sometimes returned as an Erlang list (ASN.1 constants) and sometimes as a tuple (from the decode functions). This is now changed so that OBJECT IDENTIFIER values always are represented as an Erlang tuple.
  Own Id: OTP-3280
- PER:The encode/decode functions could not handle integers with a range greater than 16#7ffffff. This limit is now removed.
  Own Id: OTP-3287
- PER: The encoding/decoding of the length for a SET OF/SEQUENCE OF was wrong if there was a size constraint. This is now corrected.
  Own Id: OTP-3291
- PER: Encoding of a constrained INTEGER (range > 16 k) was wrong for the value 0. This is now corrected.
  Own Id: OTP-3306

### 19.2 Improvements and new features

- The ASN.1 module name and the filename where the ASN.1 specification resides must match each other (has always been the case). This is now checked by the compiler. The check requires that the names match in a case or case insensitive way depending on the characteristics for the current system.
  Own Id: OTP-1843
- PER: Encode/decode of an extension value (i.e not within the root set) for ENUMERATED did not work properly. This is now corrected. If an unknown enumerated value is decoded (for an extensible enumerated type) it is returned as {asn1_enum,Value} where Value is an integer. Enumerated values in this format are also accepted by the encoder (if the value is >= the number of known extension values).
  Own Id: OTP-2930
- Unnecessary printouts from the compiler are removed. The compiler version and the compiler options are now printed to stdout.
  Own Id: OTP-3276
- In order to better suite the use of ASN.1 in embedded systems only the modules needed in runtime are now listed in the .app file.
  Own Id: OTP-3279
- The compiler now supports extensionmarker in constraint specifications. Example:

      INTEGER (0..10, ...)

  In previous version this was reported as a syntax error.
  Own Id: OTP-3281
- A very limited part of ITU-T recommendation X.681 Abstract Syntax Notation One (ASN.1): Information object specification is now implemented. Specifically TYPE IDENTIFIER is reqognized by the compiler.
  Own Id: OTP-3325
- Parameterization of ASN.1 specifications (ITU-T X.683) is now supported to a limited extent.
  Own Id: OTP-3326

## 20 Asn1 1.1.3.1

### 20.1 Fixed errors and malfunctions

- BER Encoding and decoding of ENUMERATED with extensionmark "..." did not work (crashed with a runtime error). This has now been corrected. If an unknown enumerated value is decoded (for an extensible enumerated type) it is returned as {asn1_enum,Value} where Value is an integer. Enumerated values in this format are also accepted by the encoder. ASN.1 modules containing ENUMERATED with extensionmark should be recompiled with the corrected version of the compiler. The BER runtime functions are also corrected. Note that this correction has already been delivered as a bugfix for R4B (OTP-2951).
  Own Id: OTP-3202
  Aux Id: Seq3745

## 21 Asn1 1.1.1

### 21.1 Known problems

- The syntactic construct COMPONENTS OF is not implemented.
  Own Id: OTP-2515
- ANY and ANY DEFINED BY are currently not supported.
  Own Id: OTP-2741
  Aux Id: seq 1188
- Multiple definitions of the same Type or Value is not detected by the compiler. The error occurs when the generated Erlang module is compiled.
  Own Id: OTP-3105

## 22 Asn1 1.1

### 22.1 Known problems

- The primitive/constructed bit in the tag byte of an encoding is not correct when it comes to user defined tags. For example in

       T ::= [2] SEQUENCE { a BOOLEAN}

  the tag 2 does not get the constructed bit set which it should. This is now corrected.
  Own Id: OTP-3241

### 22.2 Fixed errors and malfunctions

- The BER decoder failed to decode certain nested data types where IMPLICIT tags where involved. This is now corrected.
  Own Id: OTP-2719
  Aux Id: seq 1148
- The handling of types with extension marker "..." is corrected. Earlier each SEQUENCE and SET with an extension marker got an extra field named asn1_EXT in the generated record. This was a mistake and that field is now removed (conserns both BER and BER).
  Own Id: OTP-2724
  Aux Id: seq 1148, OTP-2719
- The decoder (both BER and PER) could not handle unnamed bits of a BIT STRING if the type had any named bits declared. This is now corrected and the unnamed bits are returned as {bit,Pos} where Pos is the bit position. The {bit,Pos} can be used as input to the encoder too.
  Own Id: OTP-2725
  Aux Id: seq 1148,OTP-2719,OTP-2724
- The functions asn1rt:decode and asn1ct:decode did not always return {ok,Result} or {error,Reason} as documented. This is now corrected.
  Own Id: OTP-2730
  Aux Id: seq 1158
- The compiler did not accept CHOICE types as components of a SEQUENCE or SET when the modules tag default was IMPLICIT. Example:

      C ::= CHOICE { ......}
      A ::= SEQUENCE {
      a [1] C, -- This was not accepted
      .....

  This was an error caused by a misinterpretation of the ASN.1 standard. This is now corrected.
  Own Id: OTP-2731
  Aux Id: seq 1163
- When decoding a SEQUENCE A which contains an OPTIONAL component b which is a SEQUENCE with mandatory components, the decoder does not detect as an error that a mandatory component of b is missing. The same error could occur also in other cases with nested types and optional components of SEQUENCE or SET. This is now corrected.
  Own Id: OTP-2738
  Aux Id: seq 1183
- BER Encoding and decoding of ENUMERATED with extensionmark "..." did not work (crashed with a runtime error). This has now been corrected. If an unknown enumerated value is decoded (for an extensible enumerated type) it is returned as {asn1_enum,Value} where Value is an integer. Enumerated values in this format are also accepted by the encoder. ASN.1 modules containing ENUMERATED with extensionmark should be recompiled with the corrected version of the compiler. The BER runtime functions are also corrected.
  Own Id: OTP-2951
  Aux Id: Seq 1446 OTP-2929
- The compiler does now accept all valid value notations for the OBJECT IDENTIFIER type. The generated code for those values is also corrected.
  Own Id: OTP-3059

### 22.3 Improvements and new features

- The code generated for BER is significantly enhanced resulting in less code and around 300% better performance in runtime for the encoding of complex ASN.1 values. The performance of decoding is unchanged.
  Own Id: OTP-2806

## 23 Asn1 1.0.3

### 23.1 Fixed errors and malfunctions

- The asn1.app file is corrected.
  Own Id: OTP-2640
- The encoding of integers in BER did not comply with the standard for all values. The values was not encoded in the minimum number of octets as required. This is now corrected in the runtime module asn1rt_ber.
  Own Id: OTP-2666

### 23.2 Improvements and new features

- The compiler now generates explicit exports directives for all generated functions that should be exported (instead of -compile(export_all)). This eliminates the warnings from the Erlang compiler when compiling the generated file.
  Own Id: OTP-1845

## 24 R3B02 (Asn1 1.0.2)

### 24.1 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

## 25 R3A (Asn1 0.9)

### 25.1 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

## 26 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.

### 26.1 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.

asn1 1.6
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