You are viewing a plain text version of this content. The canonical link for it is here.
Posted to dev@avro.apache.org by "Ryan Skraba (Jira)" <ji...@apache.org> on 2020/01/24 13:31:00 UTC
[jira] [Updated] (AVRO-2570) Code line doesn't match the code in
Avro C++ Document
[ https://issues.apache.org/jira/browse/AVRO-2570?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Ryan Skraba updated AVRO-2570:
------------------------------
Fix Version/s: 1.10.0
> Code line doesn't match the code in Avro C++ Document
> -----------------------------------------------------
>
> Key: AVRO-2570
> URL: https://issues.apache.org/jira/browse/AVRO-2570
> Project: Apache Avro
> Issue Type: Improvement
> Components: c++, doc
> Reporter: Zezeng Wang
> Assignee: Zezeng Wang
> Priority: Trivial
> Fix For: 1.10.0
>
>
> The description does not match the code in Avro C++ Document
> The following is from Avro C++ Documentation:
> *File: generated.cc*
> 1
> 19 #include "cpx.hh"
> 20 #include "avro/Encoder.hh"
> 21 #include "avro/Decoder.hh"
> 22
> 23
> 24 int
> 25 main()
> 26 {
> {color:#FF0000}27{color} std::unique_ptr<avro::OutputStream> out = avro::memoryOutputStream();
> {color:#FF0000}28{color} avro::EncoderPtr e = avro::binaryEncoder();
> {color:#FF0000}29{color} e->init(*out);
> 30 c::cpx c1;
> {color:#FF0000}31{color} c1.re = 1.0;
> 32 c1.im = 2.13;
> 33 avro::encode(*e, c1);
> 34
> 35 std::unique_ptr<avro::InputStream> in = avro::memoryInputStream(*out);
> 36 avro::DecoderPtr d = avro::binaryDecoder();
> 37 d->init(*in);
> 38
> 39 c::cpx c2;
> 40 avro::decode(*d, c2);
> 41 std::cout << '(' << c2.re << ", " << c2.im << ')' << std::endl;
> 42 return 0;
> 43 }
> In {color:#ff0000}line 9{color}, we construct a memory output stream. By this we indicate that we want to send the encoded Avro data into memory. In {color:#ff0000}line 10{color}, we construct a binary encoder, whereby we mean the output should be encoded using the Avro binary standard. In {color:#ff0000}line 11{color}, we attach the output stream to the encoder. At any given time an encoder can write to only one output stream.
> In {color:#ff0000}line 14,{color} we write the contents of c1 into the output stream using the encoder. Now the output stream contains the binary representation of the object. The rest of the code verifies that the data is indeed in the stream.
> In {color:#ff0000}line 17{color}, we construct a memory input stream from the contents of the output stream. Thus the input stream has the binary representation of the object. In {color:#ff0000}line 1{color}8 and 19, we construct a binary decoder and attach the input stream to it. {color:#ff0000}Line 22{color} decodes the contents of the stream into another object c2. Now c1 and c2 should have identical contents, which one can readily verify from the output of the program, which should be:
> (1, 2.13)
> Now, if you want to encode the data using Avro JSON encoding, you should use [avro::jsonEncoder()|http://avro.apache.org/docs/current/api/cpp/html/namespaceavro.html#a0847ef62f42f6f0d0af28da9f7c7cf15] instead of [avro::binaryEncoder()|http://avro.apache.org/docs/current/api/cpp/html/namespaceavro.html#ad0158bd2fc76615b68db68d7e4f7c4f6] in {color:#ff0000}line 10{color} and [avro::jsonDecoder()|http://avro.apache.org/docs/current/api/cpp/html/namespaceavro.html#a7ac8a9c93b0621227de3dcca383e36ff] instead of [avro::binaryDecoder()|http://avro.apache.org/docs/current/api/cpp/html/namespaceavro.html#a04f78e53cb84a0189b626e6a5726b148] in {color:#ff0000}line 18{color}.
> On the other hand, if you want to write the contents to a file instead of memory, you should use [avro::fileOutputStream()|http://avro.apache.org/docs/current/api/cpp/html/namespaceavro.html#a164e34d709ba33d2464c295e7874f784] instead of [avro::memoryOutputStream()|http://avro.apache.org/docs/current/api/cpp/html/namespaceavro.html#a0e961740e43d3f800220f03de11654e8] in {color:#ff0000}line 9{color} and [avro::fileInputStream()|http://avro.apache.org/docs/current/api/cpp/html/namespaceavro.html#a1e5251d2ad9581e353399c1bac90c9fb] instead of [avro::memoryInputStream()|http://avro.apache.org/docs/current/api/cpp/html/namespaceavro.html#a98b7a8baaef11e477db89699ab27359b] in {color:#ff0000}line 17{color}.
--
This message was sent by Atlassian Jira
(v8.3.4#803005)