KeyValuePrinter.h

/**************************************************************************
 * basf2 (Belle II Analysis Software Framework)                           *
 * Author: The Belle II Collaboration                                     *
 *                                                                        *
 * See git log for contributors and copyright holders.                    *
 * This file is licensed under LGPL-3.0, see LICENSE.md.                  *
 **************************************************************************/
 
#pragma once
 
#include <iomanip>
#include <sstream>
#include <string>
#include <vector>
#include <map>
 
namespace Belle2 {
  class KeyValuePrinter {
  public:
    explicit KeyValuePrinter(bool use_json, unsigned key_max_length = 10):
      m_json(use_json),
      m_maxpad(key_max_length + 2),
      m_delim("")
    { }
    ~KeyValuePrinter() { }
 
    std::string string() const
    {
      if (m_json)
        return "{\n" + m_stream.str() + "\n}\n";
      else
        return m_stream.str();
    }
    template <class T> void put(const std::string& key, const T& value)
    {
      if (m_json) {
        m_stream << m_delim << "\t" << escape(key) << ": " << escape(value) << "";
      } else {
        m_stream << std::left << std::setw(m_maxpad) << key + ": " << escape(value) << "\n";
      }
      m_delim = ",\n";
    }
    template <class T> void put(const std::string& key, const std::map<std::string, T>& value)
    {
      if (m_json) {
        m_stream << m_delim << "\t" << escape(key) << ": " << escape(value) << "";
      } else {
        m_stream << "\n" << key << "\n";
        for (char unused : key) {
          (void)unused;
          m_stream << '-';
        }
        m_stream << "\n" << escape(value) << "\n";
      }
      m_delim = ",\n";
    }
  private:
    bool m_json; 
    unsigned m_maxpad; 
    std::string m_delim; 
    std::stringstream m_stream; 
    std::string escape(const std::string& value) const;
    std::string escape(const char* value) const { return escape(std::string(value)); }
    template <class T> std::string escape(const T& value) const { return std::to_string(value); }
    template <class T> std::string escape(const std::vector<T>& value) const
    {
      std::string delim = "";
      std::string s = "[";
      for (auto el : value) {
        s += delim + escape(el);
        delim = ", ";
      }
      s += "]";
      return s;
    }
    template <class T> std::string escape(const std::map<std::string, T>& value) const
    {
      //well, it's valid json, but not pretty
      KeyValuePrinter printer(m_json, m_maxpad - 2);
      for (auto pair : value)
        printer.put(pair.first, pair.second);
      return printer.string();
    }
  };
}