ASN1C V7.6.x README

This file contains release notes on the latest release of the ASN1C compiler (version 7.6.x).

Contents

Introduction

Thank you for downloading this release of the ASN1C software. ASN1C is an ASN.1 compiler (code generator) capable of parsing and generating C, C++, C#, Java, Python, or Go source code for the most advanced ASN.1 syntax.

This package contains the ASN1C compiler executables and run-time libraries. Documentation is available online at https://obj-sys.com/support/asn1c-manuals.php

Release Notes

This release of ASN1C adds the following new capabilities:
Partial Decoding of PER/UPER Messages

It is now possible to configure C/C++ PER or UPER decoders to decode only parts of a message and skip over the other content.

Raw Event Parsing of PER/UPER Messages

A new capability named "raw event parsing" was added as a C/C++ PER decoding option. This is similar to the existing event parsing capabiity except that the data is not decoded prior to invoking the event callbacks. This makes it possible to skip over content that is not of interest and only target certain fields for full decoding.

Go JSON (JER) Code Generation

The capability to generate JSON Encoding Rules (JER) encoders and decoders was added for the Go language.

Go Custom Run-time Source Code Generation

The capability was added to generate a custom run-time source file (runtime.go) that only includes the run-time functions necessary for a given schema and set of compilation options. This reduces the amount of code needed to support a given project.

Improvements to ASN1C GUI

Added auto-indent capability to ASN.1 editor. Also added support for creating configuration files in ACGUI including auto-completion.

Support for 2021 ASN.1 Standards Updates

Support for features in the 2021 version of the ASN.1 standards has been added. These changes are described in the Compatibility section below.

Support for Visual Studio 2022

C/C++ run-time libraries built with Visual Studio 2020 have been added. Libraries built with Visual Studio 2013 are now not included in the SDK by default.

Update of Cryptographic Message Syntax ASN.1

Newer versions of Cryptograhic Message Syntax ASN.1 specifications have been added to the built-in schema set. This includes the 2021 updates to the Evidence Record Syntax (ERS) and Server-based Certificate Validation Protocol (SCVP) ASN.1 specifications.

Compatibility

X.697 JER 2021 adds a new encoder's option for BIT STRINGs and OCTET STRINGs that have a contents (CONTAINING) constraint. ASN1C-generated encoders will now follow this alternative encoding, and decoders will accept either option. This made the -jer+ option basically superfluous, and it has therefore been removed. Use -asnstd x680-2015 to force encoding without the new encoder's option.

X.691 PER 2021 specifies that a BIT STRING with contents constraint should be padded to a multiple of 8 bits in the aligned PER case. To control the behavior of padding for this case, use the -asnstd option. The -perpadbitstrings option has been removed.

UTF8String is no longer mapped to an array for C/C++ when -static is used.

Changes were made to Go language generation in which a Go type is now always generated for all ASN.1 type assignments. Before, certain primitive such as BOOLEAN and INTEGER would be reduced to just using the Go native type. In addition, run-time types were added for BIT STRING (asn1rt.BitString), OCTET STRING (asn1rt.OctetString), and OBJECT IDENTIFIER (asn1rt.ObjectIdentifier). These were primarily added to support JSON custom Marshal and Unmarshal or these types to allow supporting the JER content format.

Changes were made to Go language generation in which a fixed-sized byte array is no longer generated for an OCTET STRING with a fixed size constraint. The asn1rt.OctetString type is used instead which equates to a variable length byte slice.

Documentation

Documentation for this release is available online at the following URL:

https://obj-sys.com/support/asn1c-manuals.php

Windows Installation

The steps to install ASN1C on a Windows system are as follows:

  1. Download the ASN1C SDK which contains the compiler (code generator) and run-times for C/C++, Java, and C#. The C/C++ run-time contains libraries built with the Microsoft Visual Studio 2013, 2015, 2017 and 2019 compilers, the Cygwin gcc compiler, and the Minimalist GNU for Windows (MinGW) compiler.
  2. ASN1C for Windows is packaged in a self-extracting executable file format. To install, all that is necessary is to double-click the file after downloading and then following the setup wizard instructions from that point.
  3. After installation is complete, the license for the product must be installed. This can come in two forms - as a license file or a license key value. Instructions for installing the license key or file are available the the following URL:

    https://obj-sys.com/support/acguiLicInstall.php

    The compiler should now be operational. The following command can be executed:

    <rootdir>\bin\asn1c

    to verify operation.

  4. To use the Python code generation capability, the Python run-time package must first be installed. This can be done by executing the following command:
    pip install --find-links https://www.obj-sys.com/PythonRuntime --no-deps osyspyrt

Contents of the Release

The following subdirectories contain the following files (note: <installdir> refers to the installation directory that was specified during the installation process):

Base Compiler Package

<installdir>\bin\asn1c.exe

The command-line compiler executable file. This is invoked on ASN.1 or XSD source files to generate C, C++, C#, Java, Python, or Go encode/decode classes and functions. It is recommended you modify your PATH environment variable to include <installdir>\bin to allow the compiler executable to be run from anywhere.

<installdir>\bin\acgui.exe

The compiler graphic user interface (GUI) editor executable file. This GUI guides a user through the process of specifying ASN.1 or XSD source files and options. This is the program invoked from the start menu or desktop icon.

<installdir>\bin\asn2xsd.exe

ASN.1 to XML Schema (XSD) translation tool.

<installdir>\bin\berfdump.exe
<installdir>\bin\berfdump2.exe
<installdir>\bin\ber2def.exe
<installdir>\bin\ber2indef.exe

Utility programs for operating on BER-encoded files. The first program allows a file to be dumped in a human-readable format. The other two utilities convert files from the use of indefinite to definite length encoding and vice-versa.

<installdir>\bin\dumpasn1.exe

A public-domain ASN.1 BER/DER encoded data dump tool. Thanks to Peter Gutmann for making this available for public use. The full source code for this program can be found in the utils subdirectory of the installation.

<installdir>\bin\xsd2asn1.exe

XSD-to-ASN.1 translation program executable file. This program translates an XSD file to its ASN.1 equivalent as per the ITU-T X.694 standard.

<installdir>\doc

This directory contains documentation files. Note that the bulk of the documentation items are now available online (see the Documentation section above).

<installdir>\scripts

This directory contains Perl script files for doing source code editing and other transformations. The rtport.pl script is included in this release to port existing C/C++ applications that use ASN1C generated code from version 5.8 or lower to be compatible with the latest release of the product.

<installdir>\specs

This directory contains ASN.1 specifications from many standards that have been pre-compiled and tested. In some cases, syntax errors that may have existed in the original standards were fixed.

<installdir>\templates

This directory contains template files for applications such as client and server code generation. It is possible for users to alter these files to customize code that is generated or to add new template files for use with -gen-from-template command-line option.

<installdir>\utils

This directory contains the source code and build makefile for some of the utility programs included in the bin subdirectory.

<installdir>\xsd\lib\asn1.xsd

This directory contains the common XML schema definitions (XSD) library. This contains type mappings for built-in ASN.1 types that do not have an equivalent types defined in XSD.

<installdir>\xsd\sample

This directory contains sample programs related to the conversion of ASN.1 to XML Schema. It also contains the XSD.asn ASN.1 specification which contains the XSD ASN.1 module that is sometimes referenced in ASN.1 files that are the result of an XSD-to-ASN.1 translation.

C/C++ run-time libraries and source files

<installdir>\c\lib\* (Visual C++ 2017 libraries)
<installdir>\c_vs2013\lib\* (Visual C++ 2013 libraries)
<installdir>\c_vs2015\lib\* (Visual C++ 2015 libraries
<installdir>\c_vs2019\lib\* (Visual C++ 2019 libraries
<installdir>\c_gnu\lib\*.a (Cygwin GNU gcc)
<installdir>\c_mingw\lib\*.a (MinGW gcc)

The ASN1C C run-time library files. These contain low-level run-time functions for the various encoding rules supported by ASN1C. For each encoding rules type, there is a dynamic link library (.dll) and standard library file (.lib) for linking with the DLL. There is also a static library for direct linkage to the object modules (this is the library file with the '_a.lib' suffix). The licensed version of the product also contains a DLL-ready library (compiled with -MD option) for building your own value-added DLL's. Also note that the evaluation and development libraries are not fully optimized (they contain diagnostic tracing and are not compiled with compiler optimization turned on). The deployment libraries are fully optimized.

<installdir>\cpp\lib\* (Visual C++ 2017 libraries)
<installdir>\cpp_vs2013\lib\* (Visual C++ 2013 libraries)
<installdir>\cpp_vs2015\lib\* (Visual C++ 2015 libraries
<installdir>\cpp_vs2019\lib\* (Visual C++ 2019 libraries
<installdir>\cpp_gnu\lib\*.a (Cygwin GNU g++)
<installdir>\cpp_mingw\lib\*.a (MinGW g++)

The ASN1C C/C++ run-time library files. These are the same as the C run-time libraries above except they contain run-time C++ classes as well as C run-time functions.

<installdir>\c*\lib_opt\*
<installdir>\c*\lib_compact\*
<installdir>\cpp*\lib_opt\*

The optimized and/or compact version of the ASN1C run-time libraries. These libraries have all diagnostic messages, error stack trace and text, and non-essential status checks removed. The optimized libraries are built with C compiler speed optimizations options set; the compact libraries use space optimization options. (Note: these libraries are only available in the licensed deployment version of the product. If you wish to do performance testing, please contact us and we will make them available to you).

<installdir>\c*\lib_debug\*
<installdir>\cpp*\lib_debug\*

The debug DLL versions of the ASN1C run-time libraries. These are the same as the DLL C/C++ run-time libraries above except they are linked with debug versions of Standard C Run-time DLLs. (Note: these libraries are only available in the licensed development version of the product (SDK)).

<installdir>\c\sample_*
<installdir>\cpp\sample_*

The sample directories contain sample programs demonstrating the use of the compiler. There are a set of sample programs that correspond to each encoding rule set supported by ASN1C. Most sample programs are broken down into a writer and a reader. The writer encodes a sample data record and writes it to a disk file. The reader reads the encoded message from the file, decodes it, and then prints the results of the decode operation.

<installdir>\rtsrc\*
<installdir>\rtxsrc\*

Run-time source directories containing common type and class definitions used by all encoding rules. The installation run-time source directories contain the header files required to compile the compiler generated code. The C or C++ source files will also be located here if the run-time source code kit option was selected.

<installdir>\rt*ersrc\*

Run-time source directories for various ASN.1 encoding rules. These contain common code for encoding and decoding using the specific rules. Directories are currently present for BER/DER/CER, PER (aligned and unaligned), MDER, OER, and XER rules.

<installdir>\rtjsonsrc\*

JSON specific run-time source directory. These contain common code for encoding/decoding JSON messages.

<installdir>\rtxmlsrc\*

XML specific run-time source directory. These contain common code for encoding/decoding XML messages.

Java run-time libraries

<installdir>\java\asn1rt.jar

ASN.1 Java run-time libraries. These contain the low-level encode/decode classes for the various encoding rules supported by ASN1C. The asn1rt.jar file contains classes compatible with the Java 5 JRE.

<installdir>\java\sample_*

Sample programs illustrating the use of the Java version of ASN1C. As was the case for C/C++, most have a writer and a reader. Some contain support code used by other samples (for example, SimpleROSE contains the ROSE headers used by CSTA).

<installdir>\java\doc\*

The ASN.1 Java run-time libraries documentation files. These are html files generated with the javadoc documentation tool. To view the documentation, open the index.html file with a web browser and follow the hyperlinks.

<installdir>\java\xmlpull\*

The kXML pull-parser implementation. This parser is used in the generated XER and XML decode classes.

<installdir>\java\xerces\*

The Apache Xerces Java XML parser implementation. This parser is used to support legacy SAX parsing in the generated XER and XML decode classes. Note that SAX parsing is a deprecated feature at this time.

C# run-time libraries

<installdir>\csharp\asn1rt.dll

The ASN.1 C# run-time library DLL, built with Visual Studio 2015. This contains the low-level BER, PER, and/or XER encode/decode classes.

<installdir>\csharp\vs2013\asn1rt.dll

The ASN.1 C# run-time library DLL, built with Visual Studio 2013. This contains the low-level BER, PER, and/or XER encode/decode classes.

<installdir>\csharp\dotnetcore\asn1rt.dll

The ASN.1 C# run-time library DLL, built with Visual Studio 2017 and targeting .Net Core 2.0. This contains the low-level BER, PER, and/or XER encode/decode classes.

<installdir>\csharp\sample_*

Sample programs demonstrating the use of the C# version of ASN1C. As was the case for C/C++, most have a writer and a reader. Some contain support code used by other samples (for example, SimpleROSE contains the ROSE headers used by CSTA).

Python

<installdir>\python\sample_*

Sample programs demonstrating the use of the ASN1C Python code generation capability. These contain Python writer and reader script programs to encode and decode data respectively. Code can be generated using the included makefile or ASN1C GUI project file.

Go

<installdir>\golang\asn1rt

This directory contains the Go ASN.1 run-time source files that are used by the compiler to add the base run-time source code to the generated code to form a complete Go language application. Note that these files are not available in the evaluation package that is downloaded from our web-site. They are provided only for evaluation under a signed agreement. Please contact us at support@obj-sys.com if you are interested in doing a full Go evaluation.

<installdir>\golang\sample_*

Sample programs demonstrating the use of the ASN1C Go code generation capability. These contain a Go main.go file that contain a writer and reader section to encode and decode data respectively. Code can be generated using the included makefile.

Getting Started with C or C++

The compiler can be run using either the GUI or from the command line. To run the GUI, launch the application and follow these steps. To run a simple test from the command line, do the following:
  1. Open a Windows Command Prompt (Start -> Accessories -> Command Prompt) or other command shell window. If using Visual Studio, it is best to open a command prompt window for that version under the Visual Studio Tools group of the main menu pulldown item.

Getting Started with Java

The compiler can be run using either the GUI wizard or from the command line. To run the GUI wizard, launch the application and follow the steps. To run a simple test from the command line, do the following:
  1. Open a command shell window.
  2. Change directory (cd) to one of the employee sample directories (for example, java/sample_ber/Employee).
  3. Execute the build batch file:

    build

    This will cause the ASN1C compiler to be invoked to compile the employee.asn sample file. It will then invoke the Java compiler (javac) to compile all generated java files and the reader and writer programs (Note: JDK 6 was used to build all the run-time library classes). It will also automatically execute the writer and reader programs. These programs will produce a writer.log and reader.log file respectively.

    Note: a makefile is also available for use if you have a make utility program available. The makefile is compatible with the GNU make utility and with the Microsoft Visual C++ make utility (nmake).

  4. View the writer and reader log files. The writer.log file will contain a dump of the encoded message contents. The reader.log file will contain a printout of the decoded data.

Getting Started with C#

The compiler can be run using either the GUI wizard or from the command line. To run the GUI wizard, launch the application and follow the steps. To run a simple test from the command line, do the following:
  1. Make sure Microsoft .NET 2015 or 2013 is installed on your system. If using 2013, copy the asn1rt.dll file from the csharp\vs2013 folder to the csharp folder.
  2. Open the appropriate Visual Studio command prompt (VS 2015 or 2013).
  3. Execute the nmake command to run the complete sample program. The makefile will invoke the ASN1C compiler to generate C# code for the ASN.1 definition and then compile the generated C# code.
  4. Execute writer.exe to encode a binary message and write it to a file.
  5. Execute reader.exe to read the file containing encoded binary message and decode it.
Use of the .Net Core 2.0 asn1rt.dll is probably best done by creating a Visual Studio 2017 project that targets .Net Core 2.0 and that incorporates the asn1rt.dll file that's in the csharp\dotnetcore folder.

Getting Started with Python

Before Python can be used, the Python run-time must be installed using the following command:
pip install --find-links https://www.obj-sys.com/PythonRuntime --no-deps osyspyrt

The compiler can then be run using either the GUI wizard or from the command line. To run the GUI wizard, launch the application and follow the steps. To run a simple test from the command line, do the following:

  1. Open a Visual Studio command prompt window. Note that this is necessary because the Visual Studio nmake utility is used to run makefiles on Windows. cd to one of the sample directories under the python subdirectory. For example, python\sample_ber\employee.
  2. Execute the nmake command to run the complete sample program. The makefile will invoke the ASN1C compiler to generate Python code for the ASN.1 definition and then compile and run the writer.py and reader.py scripts.
  3. Execute python writer.py to encode a binary message and write it to a file.
  4. Execute python reader.py to read the file containing encoded binary message and decode it.

Note that the evaluation version of the Python code generation capability contains limits on the size of the ASN.1 files that can be compiled. It is inteneded to just demonstrate the basic functionality of this capability. To remove these limits, either a commercial-use license must be purchased, or a special evaluation license agreement signed.

Getting Started with Go

Go sample programs can be run as follows:

  1. Open a Visual Studio command prompt window. Note that this is necessary because the Visual Studio nmake utility is used to run makefiles on Windows. cd to one of the sample directories under the golang subdirectory. For example, golang\sample_per\employee.
  2. Execute the nmake command to run the complete sample program. The makefile will invoke the ASN1C compiler to generate Go code for the ASN.1 definition and then compile and run the compiled Go executable file with writer and reader arguments. The Go executable file has the same name as the sample program.
  3. Execute the Go executable with argument writer to encode a binary message and write it to a file. For the employee sample program, the command would be .\employee writer
  4. Execute the Go executable with argument reader to read the file containing encoded binary message and decode it. For the employee sample program, the command would be .\employee reader

Note that this must be done from the golang directory within the ASN1C hierarchy. A current know issue is that trying to output Go code to a directory outside the hierarchy with the -o qualifier does not work.

Also Go compilation in the evaluation version is a limited to ASN.1 files with 800 lines or less. To have this limit removed, please contact us.

Reporting Problems

Report problems you encounter by sending E-mail to support@obj-sys.com. The preferred format of example programs is the same as the sample programs. Please provide a writer and reader and indicate where in the code the problem occurs.

If you have any further questions or comments on what you would like to see in the product or what is difficult to use or understand, please communicate them to us. Your feedback is important to us. Please let us know how it works out for you - either good or bad.