streams.hpp

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// Copyright (c) 2025--present, The Simons Foundation
// This file is part of TRIQS/modest and is licensed under the terms of GPLv3 or later.
// SPDX-License-Identifier: GPL-3.0-or-later
// See LICENSE in the root of this distribution for details.
 
#pragma once
#include <ostream>
#include <streambuf>
#include <string>
 
namespace triqs {
 
 
  class ostream_with_verbosity {
 
    std::ostream *out_;
    int verbosity_;
 
    public:
    ostream_with_verbosity(std::ostream &out, int verbosity = 1) : out_(&out), verbosity_(verbosity) {}
 
    ostream_with_verbosity operator()(int n) const { return {*out_, verbosity_ - n + 1}; }
 
    template <typename T> ostream_with_verbosity &operator<<(T const &value) {
      if (verbosity_ > 0) *out_ << value;
      return *this;
    }
 
    ostream_with_verbosity &operator<<(std::ostream &(*manip)(std::ostream &)) {
      if (verbosity_ > 0) manip(*out_);
      return *this;
    }
  };
 
  // =============================================================================
 
  class indented_ostream : public std::ostream {
 
    class indented_streambuf : public std::streambuf {
      std::streambuf *dest;
      std::string head;
      bool at_line_start = true;
 
      public:
      indented_streambuf(std::streambuf *dest, int indent) : dest(dest), head(indent, ' ') {}
 
      protected:
      int_type overflow(int_type c) override {
        if (c == EOF) return !EOF;
        if (at_line_start && c != '\n') dest->sputn(head.c_str(), long(head.size()));
        at_line_start = (c == '\n');
        return dest->sputc(c); //NOLINT
      }
      int sync() override { return dest->pubsync(); }
    };
    indented_streambuf buffer;
 
    public:
    indented_ostream(std::ostream &os, int indent) : std::ostream(&buffer), buffer(os.rdbuf(), indent) {}
  };
 
} // namespace triqs