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Major Description
There's no way, that I know of, to set the precision level on the output stream.
I want to take an avro object, with double fields, and json encode it into a string. However, when I do this the encoded doubles have lost precision. I suspect this is because the precision I set on the ostringstream and resulting avro::ostreamOutputStream isn't working.
Here's an example inspired by the tutorial (http://avro.apache.org/docs/1.7.2/api/cpp/html/index.html). Using their cpx.json
00001 {
00002 "type": "record",
00003 "name": "cpx",
00004 "fields" : [
00005 {"name": "re", "type": "double"},
00006 {"name": "im", "type" : "double"}
00007 ]
00008 }
Generating cpx.hh by
avrogencpp -i cpx.json -o cpx.hh -n c
The test program is then:
1#include "cpx.hh" 2#include "avro/Compiler.hh" 3#include "avro/Encoder.hh" 4#include "avro/Decoder.hh" 5#include "avro/Specific.hh" 6#include "avro/Generic.hh" 7#include <sstream> 8#include <fstream> 9 10using namespace std; 11int main() 12{ 13 ifstream ifs("cpx.json"); 14 avro::ValidSchema type_schema; 15 avro::compileJsonSchema(ifs, type_schema); 16 17 ostringstream oss (ostringstream::out); 18 oss.precision(30); // doesn't matter 19 std::auto_ptr<avro::OutputStream> out = avro::ostreamOutputStream(oss); 20 avro::EncoderPtr e = avro::jsonEncoder(type_schema); 21 e->init(*out); 22 c::cpx complex; 23 complex.re = 1.123456789; 24 complex.im = 2.01; 25 avro::encode(*e, complex); 26 e->flush(); 27 cout.precision(30); 28 cout << oss.str() << endl; 29 30 return 0; 31}
If we then compile and run this we get:
{"re":1.12346,"im":2.01}Where as I'd expect something like:
{"re":1.12346789,"im":2.01}It doesn't seem to matter where/if we set the precision on the output stream (line 18).
Is there a different way to handle this? How do I keep the precision from getting stripped off double when doing json encoding?