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Diffstat (limited to 'lib/asn1/doc/src')
| -rw-r--r-- | lib/asn1/doc/src/asn1_ug.xml | 93 |
1 files changed, 50 insertions, 43 deletions
diff --git a/lib/asn1/doc/src/asn1_ug.xml b/lib/asn1/doc/src/asn1_ug.xml index 1da4cce5a9..2475eaa153 100644 --- a/lib/asn1/doc/src/asn1_ug.xml +++ b/lib/asn1/doc/src/asn1_ug.xml @@ -748,51 +748,58 @@ ok {ok,<<30,20,0,66,0,77,0,80,0,32,0,115,0,116,0,114,0,105,0,110,0,103>>} 7> <input>'PrimStrings':decode('BMP', Bytes3).</input> {ok,"BMP string"} </pre> - <p>The UTF8String is represented in Erlang as a list of integers, - where each integer represents the unicode value of one - character. When a value shall be encoded one first has to - transform it to a UTF8 encoded binary, then it can be encoded by - asn1. When decoding the result is a UTF8 encoded binary, which - may be transformed to an integer list. The transformation - functions, <c>utf8_binary_to_list</c> and - <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> + + <p>The UTF8String type is represented as a UTF-8 encoded binary in + Erlang. Such binaries can be created directly using the binary syntax + or by converting from a list of Unicode code points using the + <c>unicode:characters_to_binary/1</c> function.</p> + + <p>Here are some examples showing how UTF-8 encoded binaries can + be created and manipulated:</p> + + <pre> +1> <input>Gs = "Мой маленький Гном".</input> +[1052,1086,1081,32,1084,1072,1083,1077,1085,1100,1082,1080, + 1081,32,1043,1085,1086,1084] +2> <input>Gbin = unicode:characters_to_binary(Gs).</input> +<<208,156,208,190,208,185,32,208,188,208,176,208,187,208, + 181,208,189,209,140,208,186,208,184,208,185,32,208,147, + 208,...>> +3> <input>Gbin = <<"Мой маленький Гном"/utf8>>.</input> +<<208,156,208,190,208,185,32,208,188,208,176,208,187,208, + 181,208,189,209,140,208,186,208,184,208,185,32,208,147, + 208,...>> +4> <input>Gs = unicode:characters_to_list(Gbin).</input> +[1052,1086,1081,32,1084,1072,1083,1077,1085,1100,1082,1080, + 1081,32,1043,1085,1086,1084] + </pre> + + <p>See the <seealso marker="stdlib:unicode">unicode</seealso> module + for more details.</p> + + <p>In the following example we will use this ASN.1 specification:</p> <pre> -1> <input>asn1ct:compile('UTF',[ber]).</input> -Erlang ASN.1 version "1.4.3.3" compiling "UTF.asn" -Compiler Options: [ber] ---{generated,"UTF.asn1db"}-- ---{generated,"UTF.erl"}-- +UTF DEFINITIONS AUTOMATIC TAGS ::= +BEGIN + UTF ::= UTF8String +END + </pre> + + <p>Encoding and decoding a string with Unicode characters:</p> + + <pre> +5> <input>asn1ct:compile('UTF', [ber]).</input> +ok +6> <input>{ok,Bytes1} = 'UTF':encode('UTF', <<"Гном"/utf8>>).</input> +{ok,<<12,8,208,147,208,189,208,190,208,188>>} +7> <input>{ok,Bin1} = 'UTF':decode('UTF', Bytes1).</input> +{ok,<<208,147,208,189,208,190,208,188>>} +8> <input>io:format("~ts\n", [Bin1]).</input> +Гном ok -2> <input>UTF8Val1 = "hello".</input> -"hello" -3> <input>{ok,UTF8bin1} = asn1rt:utf8_list_to_binary(UTF8Val1).</input> -{ok,<<104,101,108,108,111>>} -4> <input>{ok,B}='UTF':encode('UTF',UTF8bin1).</input> -{ok,[12, - 5, - <<104,101,108,108,111>>]} -5> <input>Bin = list_to_binary(B).</input> -<<12,5,104,101,108,108,111>> -6> <input>{ok,UTF8bin1}='UTF':decode('UTF',Bin).</input> -{ok,<<104,101,108,108,111>>} -7> <input>asn1rt:utf8_binary_to_list(UTF8bin1).</input> -{ok,"hello"} -8> <input>UTF8Val2 = [16#00,16#100,16#ffff,16#ffffff].</input> -[0,256,65535,16777215] -9> <input>{ok,UTF8bin2} = asn1rt:utf8_list_to_binary(UTF8Val2).</input> -{ok,<<0,196,128,239,191,191,248,191,191,191,191>>} -10> <input>{ok,B2} = 'UTF':encode('UTF',UTF8bin2).</input> -{ok,[12, - 11, - <<0,196,128,239,191,191,248,191,191,191,191>>]} -11> <input>Bin2 = list_to_binary(B2).</input> -<<12,11,0,196,128,239,191,191,248,191,191,191,191>> -12> <input>{ok,UTF8bin2} = 'UTF':decode('UTF',Bin2).</input> -{ok,<<0,196,128,239,191,191,248,191,191,191,191>>} -13> <input>asn1rt:utf8_binary_to_list(UTF8bin2).</input> -{ok,[0,256,65535,16777215]} -14> </pre> +9> <input>unicode:characters_to_list(Bin1).</input> +[1043,1085,1086,1084] + </pre> </section> <section> |