diff options
Diffstat (limited to 'lib/asn1/doc/src/asn1_ug.xml')
-rw-r--r-- | lib/asn1/doc/src/asn1_ug.xml | 519 |
1 files changed, 76 insertions, 443 deletions
diff --git a/lib/asn1/doc/src/asn1_ug.xml b/lib/asn1/doc/src/asn1_ug.xml index 1b399fb641..362ca9330f 100644 --- a/lib/asn1/doc/src/asn1_ug.xml +++ b/lib/asn1/doc/src/asn1_ug.xml @@ -4,7 +4,7 @@ <chapter> <header> <copyright> - <year>1997</year><year>2011</year> + <year>1997</year><year>2013</year> <holder>Ericsson AB. All Rights Reserved.</holder> </copyright> <legalnotice> @@ -186,13 +186,21 @@ END </pre> The following shows how the compiler can be called from the Erlang shell:</p> <pre> -1><input>asn1ct:compile("People",[ber_bin]).</input> +1><input>asn1ct:compile("People", [ber]).</input> +ok +2> </pre> + + <p>The <c>verbose</c> option can be given to have information + about the generated files printed:</p> + <pre> +2><input>asn1ct:compile("People", [ber,verbose]).</input> Erlang ASN.1 compiling "People.asn" --{generated,"People.asn1db"}-- --{generated,"People.hrl"}-- --{generated,"People.erl"}-- ok -2> </pre> +3> </pre> + <p>The ASN.1 module People is now accepted and the abstract syntax tree is saved in the <c>People.asn1db</c> file, the generated Erlang code is compiled using the Erlang compiler and @@ -229,7 +237,7 @@ receive constructed and encoded using <c>'People':encode('Person',Answer)</c> which takes an instance of a defined ASN.1 type and transforms it to a - (possibly) nested list of bytes according to the BER or PER + binary according to the BER or PER encoding-rules. <br></br> The encoder and the decoder can also be run from @@ -239,24 +247,12 @@ The encoder and the decoder can also be run from <pre> 2> <input>Rockstar = {'Person',"Some Name",roving,50}.</input> {'Person',"Some Name",roving,50} -3> <input>{ok,Bytes} = asn1rt:encode('People','Person',Rockstar).</input> -{ok,[<<243>>, - [17], - [19,9,"Some Name"], - [2,1,[2]], - [2,1,"2"]]} -4> <input>Bin = list_to_binary(Bytes).</input> -<<243,17,19,9,83,111,109,101,32,78,97,109,101,2,1,2,2,1,50>> -5> <input>{ok,Person} = asn1rt:decode('People','Person',Bin).</input> +3> <input>{ok,Bin} = asn1rt:encode('People','Person',Rockstar).</input> +{ok,<<243,17,19,9,83,111,109,101,32,78,97,109,101,2,1,2, + 2,1,50>>} +4> <input>{ok,Person} = asn1rt:decode('People','Person',Bin).</input> {ok,{'Person',"Some Name",roving,50}} -6> </pre> - <p>Notice that the result from <c>encode</c> is a nested list which - must be turned into a binary before the call to <c>decode</c>. A - binary is necessary as input to decode since the module was compiled - with the <c>ber_bin</c> option - The reason for returning a nested list is that it is faster to produce - and the <c>list_to_binary</c> operation is - performed automatically when the list is sent via the Erlang port mechanism.</p> +5> </pre> </section> <section> @@ -305,17 +301,15 @@ The encoder and the decoder can also be run from ASN.1 compiler:</p> <pre> erlc Person.asn -erlc -bper_bin Person.asn -erlc -bber_bin +optimize ../Example.asn +erlc -bper Person.asn +erlc -bber ../Example.asn erlc -o ../asnfiles -I ../asnfiles -I /usr/local/standards/asn1 Person.asn </pre> <p>The useful options for the ASN.1 compiler are:</p> <taglist> - <tag><c>-b[ber | per | ber_bin | per_bin | uper_bin]</c></tag> + <tag><c>-b[ber | per | uper]</c></tag> <item> <p>Choice of encoding rules, if omitted <c>ber</c> is the - default. The <c>ber_bin</c> and <c>per_bin</c> options - allows for optimizations and are therefore recommended - instead of the <c>ber</c> and <c>per</c> options.</p> + default.</p> </item> <tag><c>-o OutDirectory</c></tag> <item> @@ -330,51 +324,14 @@ erlc -o ../asnfiles -I ../asnfiles -I /usr/local/standards/asn1 Person.asn are several places to search in. The compiler will always search the current directory first.</p> </item> - <tag><c>+compact_bit_string</c></tag> - <item> - <p>Gives the user the option to use a compact format of the BIT - STRING type to save memory space, typing space and - increase encode/decode performance, for details see - <seealso marker="#BIT STRING">BIT STRING </seealso>type section.</p> - </item> <tag><c>+der</c></tag> <item> - <p>DER encoding rule. Only when using <c>-ber</c> or - <c>-ber_bin</c> option.</p> - </item> - <tag><c>+optimize</c></tag> - <item> - <p>This flag has effect only when used together with one of - <c>per_bin</c> or <c>ber_bin</c> flags. It gives time optimized - code in the generated modules and it uses another runtime module. - In the <c>per_bin</c> case a nif is used. The - result from an encode is a binary.</p> - <p><em>When this flag is used you cannot use the old format</em><c>{TypeName,Value}</c> when you encode values. Since it is - an unnecessary construct it has been removed in favor of - performance. It - is neither admitted to construct SEQUENCE or SET component values - with the format <c>{ComponentName,Value}</c> since it also is - unnecessary. The only case were it is necessary is in a CHOICE, - were you have to pass values to the right component by specifying - <c>{ComponentName,Value}</c>. See also about - <seealso marker="#TypeNameValue">{Typename,Value}</seealso> below - and in the sections for each type.</p> - </item> - <tag><c>+driver</c></tag> - <item> - <p>As of R15B this means the same as the <c>nif</c> option. Kept for - backwards compatability reasons.</p> - </item> - <tag><c>+nif</c></tag> - <item> - <p>Together with the flags <c>ber_bin</c> - and <c>optimize</c> you choose to use a nif for considerable - faster encode and decode. </p> + <p>DER encoding rule. Only when using <c>-ber</c> option.</p> </item> <tag><c>+asn1config</c></tag> <item> <p>This functionality works together with the flags - <c>ber_bin</c> and <c>optimize</c>. You enables the + <c>ber</c>. It enables the specialized decodes, see the <seealso marker="asn1_spec">Specialized Decode</seealso> chapter. </p> </item> @@ -388,22 +345,6 @@ erlc -o ../asnfiles -I ../asnfiles -I /usr/local/standards/asn1 Person.asn list or a binary. Earlier versions of the compiler ignored those following bytes.</p> </item> - <tag><c>{inline,OutputName}</c></tag> - <item> - <p>Compiling with this option gives one output module - containing all asn1 run-time functionality. The asn1 specs - are provided in a target module <c>Module.set.asn</c> as - described in the <seealso marker="asn1ct#asn1set">reference manual</seealso>. The name of the resulting module - containing generated encode/decode functions and inlined - run-time functions will be <c>OutputName.erl</c>. The - merging/inlining of code is done by the <c>igor</c> module - of <c>syntax_tools</c>. By default the functions generated - from the first asn1 spec in the <c>.set.asn</c> are - exported, unless a <c>{export,[atom()]}</c> or - <c>{export_all,true}</c> option are provided. The list of - atoms are names of choosen asn1 specs from the - <c>.set.asn</c> file. See further examples of usage <seealso marker="#inlineExamples">below</seealso></p> - </item> <tag><c>+'Any Erlc Option'</c></tag> <item> <p>You may add any option to the Erlang compiler when @@ -413,7 +354,6 @@ erlc -o ../asnfiles -I ../asnfiles -I /usr/local/standards/asn1 Person.asn </item> </taglist> <p>For a complete description of <c>erlc</c> see Erts Reference Manual.</p> - <p>For preferred option use see <seealso marker="#preferred option use">Preferred Option Use</seealso> section.</p> <p>The compiler and other compile-time functions can also be invoked from the Erlang shell. Below follows a brief description of the primary functions, for a @@ -429,9 +369,9 @@ asn1ct:compile("H323-MESSAGES.asn1"). </pre> <p>which equals:</p> <pre> asn1ct:compile("H323-MESSAGES.asn1",[ber]). </pre> - <p>If one wants PER encoding with optimizations:</p> + <p>If one wants PER encoding:</p> <pre> -asn1ct:compile("H323-MESSAGES.asn1",[per_bin,optimize]). </pre> +asn1ct:compile("H323-MESSAGES.asn1",[per]). </pre> <p>The generic encode and decode functions can be invoked like this:</p> <pre> asn1ct:encode('H323-MESSAGES','SomeChoiceType',{call,"octetstring"}). @@ -443,269 +383,6 @@ asn1ct:decode('H323-MESSAGES','SomeChoiceType',Bytes). </pre> </section> <section> - <marker id="preferred option use"></marker> - <title>Preferred Option Use</title> - <p> - It may not be obvious which compile options best fit a - situation. This section describes the format of the result of - encode and decode. It also gives some performance statistics - when using certain options. Finally there is a recommendation - which option combinations should be used. - </p> - <p> - The default option is <c>ber</c>. It is the same backend as - <c>ber_bin</c> except that the result of encode is transformed - to a flat list. Below is a table that gives the different - formats of input and output of encode and decode using the - <em>allowed combinations</em> of coding and optimization - options: (EAVF stands for how ASN1 values are represented in - Erlang which is described in the <seealso - marker="#ASN1Types">ASN1 Types chapter</seealso>) - </p> - <table> - <row> - <cell align="left" valign="middle"><em>Encoding Rule</em></cell> - <cell align="left" valign="middle"><em>Compile options, allowed combinations</em></cell> - <cell align="left" valign="middle"><em>encode input</em></cell> - <cell align="left" valign="middle"><em>encode output</em></cell> - <cell align="left" valign="middle"><em>decode input</em></cell> - <cell align="left" valign="middle"><em>decode output</em></cell> - </row> - <row> - <cell align="left" valign="middle">BER</cell> - <cell align="left" valign="middle">[ber] (default)</cell> - <cell align="left" valign="middle">EAVF</cell> - <cell align="left" valign="middle">flat list</cell> - <cell align="left" valign="middle">flat list / binary</cell> - <cell align="left" valign="middle">EAVF</cell> - </row> - <row> - <cell align="left" valign="middle">BER</cell> - <cell align="left" valign="middle">[ber_bin]</cell> - <cell align="left" valign="middle">EAVF</cell> - <cell align="left" valign="middle">iolist</cell> - <cell align="left" valign="middle">binary</cell> - <cell align="left" valign="middle">EAVF</cell> - </row> - <row> - <cell align="left" valign="middle">BER</cell> - <cell align="left" valign="middle"><em>[ber_bin, optimize]</em></cell> - <cell align="left" valign="middle">EAVF</cell> - <cell align="left" valign="middle">iolist</cell> - <cell align="left" valign="middle">binary</cell> - <cell align="left" valign="middle">EAVF</cell> - </row> - <row> - <cell align="left" valign="middle">BER</cell> - <cell align="left" valign="middle"><em>[ber_bin, optimize, nif]</em></cell> - <cell align="left" valign="middle">EAVF</cell> - <cell align="left" valign="middle">iolist</cell> - <cell align="left" valign="middle">iolist / binary</cell> - <cell align="left" valign="middle">EAVF</cell> - </row> - <row> - <cell align="left" valign="middle">PER aligned variant</cell> - <cell align="left" valign="middle">[per]</cell> - <cell align="left" valign="middle">EAVF</cell> - <cell align="left" valign="middle">flat list</cell> - <cell align="left" valign="middle">flat list</cell> - <cell align="left" valign="middle">EAVF</cell> - </row> - <row> - <cell align="left" valign="middle">PER aligned variant</cell> - <cell align="left" valign="middle"><em>[per_bin]</em></cell> - <cell align="left" valign="middle">EAVF</cell> - <cell align="left" valign="middle">iolist / binary</cell> - <cell align="left" valign="middle">binary</cell> - <cell align="left" valign="middle">EAVF</cell> - </row> - <row> - <cell align="left" valign="middle">PER aligned variant</cell> - <cell align="left" valign="middle"><em>[per_bin, optimize]</em></cell> - <cell align="left" valign="middle">EAVF</cell> - <cell align="left" valign="middle">binary</cell> - <cell align="left" valign="middle">binary</cell> - <cell align="left" valign="middle">EAVF</cell> - </row> - <row> - <cell align="left" valign="middle">PER unaligned variant</cell> - <cell align="left" valign="middle"><em>[uper_bin]</em></cell> - <cell align="left" valign="middle">EAVF</cell> - <cell align="left" valign="middle">binary</cell> - <cell align="left" valign="middle">binary</cell> - <cell align="left" valign="middle">EAVF</cell> - </row> - - <row> - <cell align="left" valign="middle">DER</cell> - <cell align="left" valign="middle">[(ber), der]</cell> - <cell align="left" valign="middle">EAVF</cell> - <cell align="left" valign="middle">flat list</cell> - <cell align="left" valign="middle">flat list / binary</cell> - <cell align="left" valign="middle">EAVF</cell> - </row> - <row> - <cell align="left" valign="middle">DER</cell> - <cell align="left" valign="middle">[ber_bin, der]</cell> - <cell align="left" valign="middle">EAVF</cell> - <cell align="left" valign="middle">iolist</cell> - <cell align="left" valign="middle">binary</cell> - <cell align="left" valign="middle">EAVF</cell> - </row> - <row> - <cell align="left" valign="middle">DER</cell> - <cell align="left" valign="middle"><em>[ber_bin, optimize, der]</em></cell> - <cell align="left" valign="middle">EAVF</cell> - <cell align="left" valign="middle">iolist</cell> - <cell align="left" valign="middle">binary</cell> - <cell align="left" valign="middle">EAVF</cell> - </row> - <row> - <cell align="left" valign="middle">DER</cell> - <cell align="left" valign="middle"><em>[ber_bin, optimize, nif, der]</em></cell> - <cell align="left" valign="middle">EAVF</cell> - <cell align="left" valign="middle">iolist</cell> - <cell align="left" valign="middle">binary</cell> - <cell align="left" valign="middle">EAVF</cell> - </row> - - - <tcaption>The output / input formats for different combinations of compile options.</tcaption> - </table> - <p> - Encode / decode speed comparison in one user case for the above - alternatives (except <c>DER</c>) is showed in the table below. The - <c>DER</c> alternatives are slower than their corresponding - <c>BER</c> alternative. - </p> - - <table> - <row> - <cell align="left" valign="middle"><em>compile options</em></cell> - <cell align="left" valign="middle"><em>encode time</em></cell> - <cell align="left" valign="middle"><em>decode time</em></cell> - </row> - <row> - <cell align="left" valign="middle">[ber]</cell> - <cell align="left" valign="middle">120</cell> - <cell align="left" valign="middle">162</cell> - </row> - <row> - <cell align="left" valign="middle">[ber_bin]</cell> - <cell align="left" valign="middle">124</cell> - <cell align="left" valign="middle">154</cell> - </row> - <row> - <cell align="left" valign="middle"><em>[ber_bin, optimize]</em></cell> - <cell align="left" valign="middle">50</cell> - <cell align="left" valign="middle">78</cell> - </row> - <row> - <cell align="left" valign="middle"><em>[ber_bin, optimize, driver]</em></cell> - <cell align="left" valign="middle">50</cell> - <cell align="left" valign="middle">62</cell> - </row> - <row> - <cell align="left" valign="middle">[per]</cell> - <cell align="left" valign="middle">141</cell> - <cell align="left" valign="middle">133</cell> - </row> - <row> - <cell align="left" valign="middle"><em>[per_bin]</em></cell> - <cell align="left" valign="middle">125</cell> - <cell align="left" valign="middle">123</cell> - </row> - <row> - <cell align="left" valign="middle"><em>[per_bin, optimize]</em></cell> - <cell align="left" valign="middle">77</cell> - <cell align="left" valign="middle">72</cell> - </row> - <row> - <cell align="left" valign="middle"><em>[uper_bin]</em></cell> - <cell align="left" valign="middle">97</cell> - <cell align="left" valign="middle">104</cell> - </row> - <tcaption> - One example of difference in speed for the compile option alternatives. - </tcaption> - </table> - - <p> - The compile options <c>ber</c>, <c>per</c> and - <c>driver</c> are kept for backwards compatibility and should not be - used in new code. The nif implementation which replaces the linked-in - driver has been shown to be about 5-15% faster. - </p> - <p> - You are strongly recommended to use the appropriate alternative - of the bold typed options. The <c>optimize</c> and - <c>nif</c> options does not affect the encode or decode - result, just the time spent in run-time. When <c>ber_bin</c> and - <c>nif</c> or <c>per_bin</c> and <c>optimize</c> is - combined the C-code nif is used in chosen parts of encode / - decode procedure. - </p> - <table> - <row> - <cell align="left" valign="middle"><em>Compile options, allowed combinations</em></cell> - <cell align="left" valign="middle"><em>use of nif</em></cell> - </row> - <row> - <cell align="left" valign="middle">[ber]</cell> - <cell align="left" valign="middle">no</cell> - </row> - <row> - <cell align="left" valign="middle">[ber_bin]</cell> - <cell align="left" valign="middle">no</cell> - </row> - <row> - <cell align="left" valign="middle"><em>[ber_bin, optimize]</em></cell> - <cell align="left" valign="middle">no</cell> - </row> - <row> - <cell align="left" valign="middle"><em>[ber_bin, optimize, nif]</em></cell> - <cell align="left" valign="middle">yes</cell> - </row> - <row> - <cell align="left" valign="middle">[per]</cell> - <cell align="left" valign="middle">no</cell> - </row> - <row> - <cell align="left" valign="middle"><em>[per_bin]</em></cell> - <cell align="left" valign="middle">no</cell> - </row> - <row> - <cell align="left" valign="middle"><em>[per_bin, optimize]</em></cell> - <cell align="left" valign="middle">yes</cell> - </row> - <row> - <cell align="left" valign="middle"><em>[uper_bin]</em></cell> - <cell align="left" valign="middle">no</cell> - </row> - - <row> - <cell align="left" valign="middle">[(ber), der]</cell> - <cell align="left" valign="middle">no</cell> - </row> - <row> - <cell align="left" valign="middle">[ber_bin, der]</cell> - <cell align="left" valign="middle">no</cell> - </row> - <row> - <cell align="left" valign="middle"><em>[ber_bin, optimize, der]</em></cell> - <cell align="left" valign="middle">no</cell> - </row> - <row> - <cell align="left" valign="middle"><em>[ber_bin, optimize, nif, der]</em></cell> - <cell align="left" valign="middle">yes</cell> - </row> - - - <tcaption>When the ASN1 nif is used.</tcaption> - </table> - - </section> - <section> <title>Run-time Functions</title> <p>A brief description of the major functions is given here. For a complete description of each function see @@ -719,9 +396,9 @@ asn1rt:decode('H323-MESSAGES','SomeChoiceType',Bytes). </pre> 'H323-MESSAGES':encode('SomeChoiceType',{call,"octetstring"}). 'H323-MESSAGES':decode('SomeChoiceType',Bytes). </pre> <p>The asn1 nif is enabled in two occasions: encoding of - asn1 values when the asn1 spec is compiled with <c>per_bin</c> and - <c>optimize</c> or decode of encoded asn1 values when the asn1 spec is - compiled with <c>ber_bin</c>, <c>optimize</c> and <c>nif</c>. In + asn1 values when the asn1 spec is compiled with <c>per</c> and + or decode of encoded asn1 values when the asn1 spec is + compiled with <c>ber</c>. In those cases the nif will be loaded automatically at the first call to <c>encode</c>/<c>decode</c>. If one doesn't want the performance overhead of the nif being loaded at the first call it is possible @@ -754,21 +431,8 @@ asn1rt:decode('H323-MESSAGES','SomeChoiceType',Bytes). </pre> any reason. Maybe you need to compile the same specs for different encoding/decoding standards.</item> <item>You want only one resulting module.</item> - <item>If it is crucial to have a minimal system. Using - <c>{inline,OutputModule}</c> includes all necessary run-time - functions of the asn1 application, but skips those modules not - used.</item> - <item>Upgrading issues: Even if you upgrade your Erlang system - you may want to continue running the old asn1 run-time - functionality.</item> - <item>Performance issues: If you have an asn1 system with a lot - of cross references you may gain in performance. Measurements - must be done for each case.</item> </list> - <p>You may choose either the plain multi file compilation that just - merges the chosen asn1 specs or the <c>{inline,OutputModule}</c> - that also includes the used asn1 run-time functionality.</p> - <p>For both cases you need to specify which asn1 specs you will + <p>You need to specify which asn1 specs you will compile in a module that must have the extension <c>.set.asn</c>. You chose name of the module and provide the names of the asn1 specs. For instance, if you have the specs @@ -782,17 +446,7 @@ File3.asn </pre> <code type="none"> ~> erlc MyModule.set.asn </code> <p>the result will be one merged module <c>MyModule.erl</c> with - the generated code from the three asn1 specs. But if you compile - with:</p> - <code type="none"> -~> erlc +"{inline,'OutputModule'}" MyModule.set.asn </code> - <p>the result will be a module <c>OutputModule.erl</c> that - contains all encode/decode functions for the three asn1 specs and - all used functions from the asn1 run-time modules, in this case - <c>asn1rt_ber_bin</c>. In the former case all encode/decode - functions are exported but in the latter only the encode/decode - functions of the first spec in the <c>.set.asn</c>, i.e. those - from <c>File1.asn</c>. + the generated code from the three asn1 specs. </p> </section> @@ -868,26 +522,6 @@ Operational ::= BOOLEAN --ASN.1 definition </pre> <pre> Val = true, {ok,Bytes}=asn1rt:encode(MyModule,'Operational',Val), </pre> - <p>For historical reasons it is also possible to assign ASN.1 values - in Erlang using a tuple notation - with type and value as this</p> - <pre> -Val = {'Operational',true} </pre> - <warning> - <marker id="warning"></marker> - <p>The tuple notation, <c>{Typename, Value}</c> is only kept - because of backward compatibility and may be withdrawn in a - future release. If the notation is used the <c>Typename</c> - element must be spelled correctly, otherwise a run-time error - will occur. - </p> - <p>If the ASN.1 module is compiled with the flags - <c>per_bin</c> or <c>ber_bin</c> and <c>optimize</c> it is not - allowed to use the tuple notation. That possibility has been - removed due to performance reasons. Neither is it allowed to - use the <c>{ComponentName,Value}</c> notation in case of a - SEQUENCE or SET type.</p> - </warning> <p>Below follows a description of how values of each type can be represented in Erlang. </p> @@ -1008,7 +642,7 @@ Day1 = saturday, <section> <marker id="BIT STRING"></marker> - <title>BIT STRING </title> + <title>BIT STRING</title> <p>The BIT STRING type can be used to model information which is made up of arbitrary length series of bits. It is intended to be used for a selection of flags, not for binary files. <br></br> @@ -1019,56 +653,66 @@ Day1 = saturday, Bits1 ::= BIT STRING Bits2 ::= BIT STRING {foo(0),bar(1),gnu(2),gnome(3),punk(14)} </pre> - <p>There are four different notations available for representation of + <p>There are five different notations available for representation of BIT STRING values in Erlang and as input to the encode functions.</p> <list type="ordered"> - <item>A list of binary digits (0 or 1).</item> - <item>A hexadecimal number (or an integer). This format should be - avoided, since it is easy to misinterpret a <c>BIT STRING</c> - value in this format. This format may be withdrawn in a future - release.</item> + <item>A bitstring. By default, a BIT STRING with no + symbolic names will be decoded to an Erlang bitstring.</item> <item>A list of atoms corresponding to atoms in the <c>NamedBitList</c> - in the BIT STRING definition.</item> + in the BIT STRING definition. A BIT STRING with symbolic + names will always be decoded to this format.</item> + <item>A list of binary digits (0 or 1). This format is always + accepted as input to the encode functions. A BIT STRING will + be decoded to this format if <em>legacy_bit_string</em> option + has been given. <em>This format may be withdrawn in a future + release.</em> + </item> <item>As <c>{Unused,Binary}</c> where <c>Unused</c> denotes how - many trailing zero-bits 0 to 7 that are unused in the least - significant byte in <c>Binary</c>. This notation is only - available when the ASN.1 files have been compiled with the - <em>+compact_bit_string</em> flag in the option list. In - this case it is possible to use all kinds of notation when - encoding. But the result when decoding is always in the - compact form. The benefit from this notation is a more - compact notation when one has large BIT STRINGs. The - encode/decode performance is also much better in the case of - large BIT STRINGs. </item> + many trailing zero-bits 0 to 7 that are unused in the least + significant byte in <c>Binary</c>. This format is always + accepted as input to the encode functions. A BIT STRING will + be decoded to this format if <em>compact_bit_string</em> has + been given. <em>This format may be withdrawn in a future + release.</em> + </item> + <item>A hexadecimal number (or an integer). This format should be + avoided, since it is easy to misinterpret a <c>BIT STRING</c> + value in this format. <em>This format may be withdrawn in a future + release.</em> + </item> </list> <note> - <p>Note that it is advised not to use the integer format of a - BIT STRING, see the second point above.</p> + <p>It is recommended to either use the bitstring format (for + BIT STRINGs with no symbolic names) or a list of symbolic + names (for BIT STRINGs with symbolic names). The other formats + should be avoided since they may be withdrawn in a future + release. + </p> </note> <pre> -Bits1Val1 = [0,1,0,1,1], +Bits1Val1 = <<0:1,1:1,0:1,1:1,1:1>>, Bits1Val2 = 16#1A, -Bits1Val3 = {3,<<0:1,1:1,0:1,1:1,1:1,0:3>>} +Bits1Val3 = {3,<<0:1,1:1,0:1,1:1,1:1,0:3>>}, +Bits1Val4 = [0,1,0,1,1] </pre> - <p>Note that <c>Bits1Val1</c>, <c>Bits1Val2</c> and <c>Bits1Val3</c> - denote the same value.</p> + <p>Note that <c>Bits1Val1</c>, <c>Bits1Val2</c>, <c>Bits1Val3</c>, + and <c>Bits1Val1</c> denote the same value.</p> <pre> Bits2Val1 = [gnu,punk], -Bits2Val2 = 2#1110, +Bits2Val2 = <<2#1110:4>>, Bits2Val3 = [bar,gnu,gnome], -Bits2Val4 = [0,1,1,1] </pre> - <p>The above <c>Bits2Val2</c>, <c>Bits2Val3</c> and <c>Bits2Val4</c> - also all denote the same value.</p> + <p><c>Bits2Val2</c> and <c>Bits2Val3</c> above denote the same value.</p> <p><c>Bits2Val1</c> is assigned symbolic values. The assignment means that the bits corresponding to <c>gnu</c> and <c>punk</c> i.e. bits 2 and 14 are set to 1 and the rest set to 0. The symbolic values appear as a list of values. If a named value appears, which is not specified in the type definition, a run-time error will occur.</p> <p>The compact notation equivalent to the empty BIT STRING is - <c><![CDATA[{0,<<>>}]]></c>, which in the other notations is <c>[]</c> or + <c><![CDATA[{0,<<>>}]]></c>, which in the other notations is + <c><![CDATA[<<>>]]></c>, <c>[]</c>, or <c>0</c>.</p> - <p>BIT STRINGS may also be sub-typed with for example a SIZE + <p>BIT STRINGS may also be sub-typed with, for example, a SIZE specification:</p> <pre> Bits3 ::= BIT STRING (SIZE(0..31)) </pre> @@ -1149,7 +793,7 @@ TextFileVal2 = [88,76,55,44,99,121 .......... a lot of characters here ....] The following example shows how it works:</p> <p>In a file <c>PrimStrings.asn1</c> the type <c>BMP</c> is defined as <br></br> -<c>BMP ::= BMPString</c> then using BER encoding (<c>ber_bin</c> +<c>BMP ::= BMPString</c> then using BER encoding (<c>ber</c> option)the input/output format will be:</p> <pre> 1> <input>{ok,Bytes1} = asn1rt:encode('PrimStrings','BMP',[{0,0,53,53},{0,0,45,56}]).</input> @@ -1174,9 +818,9 @@ TextFileVal2 = [88,76,55,44,99,121 .......... a lot of characters here ....] <c>utf8_list_to_binary</c>, are in the <c>asn1rt</c> module. In the example below we assume an asn1 definition <c>UTF ::= UTF8String</c> in a module <c>UTF.asn</c>:</p> <pre> -1> <input>asn1ct:compile('UTF',[ber_bin]).</input> +1> <input>asn1ct:compile('UTF',[ber]).</input> Erlang ASN.1 version "1.4.3.3" compiling "UTF.asn" -Compiler Options: [ber_bin] +Compiler Options: [ber] --{generated,"UTF.asn1db"}-- --{generated,"UTF.erl"}-- ok @@ -1287,14 +931,6 @@ Pdu ::= SEQUENCE { <p>Values can be assigned in Erlang as shown below:</p> <pre> MyPdu = #'Pdu'{a=22,b=77.99,c={0,1,2,3,4},d='NULL'}. </pre> -<note> - <p> - In very early versions of the asn1 compiler it was also possible to - specify the values of the components in - a SEQUENCE or a SET as a list of tuples <c>{ComponentName,Value}</c>. - This is no longer supported. - </p> -</note> <p>The decode functions will return a record as result when decoding a <c>SEQUENCE</c> or a <c>SET</c>. <marker id="DEFAULT"></marker> @@ -1739,12 +1375,9 @@ SS ::= SET { 1> <input>Val = 'Values':tt().</input> {'TT',77,["kalle","kula"]} 2> <input>{ok,Bytes} = 'Values':encode('TT',Val).</input> -{ok,["0", - [18], - [[[128],[1],"M"],["\\241","\\r",[[[4],[5],"kalle"],[[4],[4],"kula"]]]]]} -3> <input>FlatBytes = lists:flatten(Bytes).</input> -[48,18,128,1,77,161,13,4,5,107,97,108,108,101,4,4,107,117,108,97] -4> <input>'Values':decode('TT',FlatBytes).</input> +{ok,<<48,18,128,1,77,161,13,4,5,107,97,108,108,101,4,4, + 107,117,108,97>>} +4> <input>'Values':decode('TT',Bytes).</input> {ok,{'TT',77,["kalle","kula"]}} 5> </pre> |