eic-opticks/sysrap/sdirect.h

0001 #pragma once
0002 /**
0003 sdirect.h : Stream redirection to silence noisy code unless VERBOSE is defined
0004 ================================================================================
0005
0006 Refs:
0007
0008 * http://stackoverflow.com/questions/5419356/redirect-stdout-stderr-to-a-string
0009 * http://wordaligned.org/articles/cpp-streambufs
0010
0011
0012 Usage::
0013
0014     std::stringstream coutbuf;
0015     std::stringstream cerrbuf;
0016     {
0017         sdirect::cout_(coutbuf.rdbuf());
0018         sdirect::cerr_(cerrbuf.rdbuf());
0019
0020         m_dc = new DetectorConstruction ;  // noisy code
0021    }
0022    std::string out = coutbuf.str();
0023    std::string err = cerrbuf.str();
0024    bool verbose = getenv("VERBOSE") != nullptr ;
0025    std::cout << sdirect::OutputMessage("DetectorConstruction", out, err, verbose );
0026
0027
0028 **/
0029
0030 #include <iostream>
0031 #include <iomanip>
0032 #include <streambuf>
0033 #include <sstream>
0034 #include <string>
0035
0036 namespace sdirect
0037 {
0038     struct cout_
0039     {
0040         std::streambuf* old;
0041
0042         cout_( std::streambuf* newbuf )
0043            :
0044            old( std::cout.rdbuf(newbuf) )
0045         {}
0046
0047         ~cout_()
0048         {
0049             std::cout.rdbuf( old );
0050         }
0051
0052     };
0053
0054     struct cerr_
0055     {
0056         std::streambuf* old;
0057
0058         cerr_( std::streambuf* newbuf )
0059            :
0060            old( std::cerr.rdbuf(newbuf) )
0061         {}
0062
0063         ~cerr_()
0064         {
0065             std::cerr.rdbuf( old );
0066         }
0067     };
0068
0069     // allows code expecting to write to file to
0070     // be tricked into writing to a string
0071     struct ostream_
0072     {
0073         std::ostream& src;
0074         std::streambuf * const sbuf;
0075
0076         ostream_(std::ostream& dst, std::ostream& src)
0077             :
0078             src(src),
0079             sbuf(src.rdbuf(dst.rdbuf()))
0080         {
0081         }
0082
0083         ~ostream_()
0084         {
0085             src.rdbuf(sbuf);
0086         }
0087     };
0088
0089
0090     inline std::string OutputMessage(const char* msg, const std::string& out, const std::string& err, bool verbose )  // static
0091     {
0092         std::stringstream ss ;
0093
0094         ss << std::left << std::setw(30) << msg << std::right
0095            << " yielded chars : "
0096            << " cout " << std::setw(6) << out.size()
0097            << " cerr " << std::setw(6) << err.size()
0098            << " : set VERBOSE to see them "
0099            << std::endl
0100            ;
0101
0102         if(verbose)
0103         {
0104             ss << "cout[" << std::endl << out << "]" << std::endl  ;
0105             ss << "cerr[" << std::endl << err << "]" << std::endl  ;
0106         }
0107         std::string s = ss.str();
0108         return s ;
0109     }
0110 }
0111
0112