slog.hpp

// Copyright (C) 2018-2024 Intel Corporation
// SPDX-License-Identifier: Apache-2.0
//
 
#pragma once
 
#include <iostream>
#include <string>
 
namespace slog {
 
class LogStreamEndLine { };
 
static constexpr LogStreamEndLine endl;
 
 
class LogStreamBoolAlpha { };
 
static constexpr LogStreamBoolAlpha boolalpha;
 
 
class LogStream {
    std::string _prefix;
    std::ostream* _log_stream;
    bool _new_line;
 
public:
    LogStream(const std::string &prefix, std::ostream& log_stream)
            : _prefix(prefix), _new_line(true) {
        _log_stream = &log_stream;
    }
 
    template<class T>
    LogStream &operator<<(const T &arg) {
        if (_new_line) {
            (*_log_stream) << "[ " << _prefix << " ] ";
            _new_line = false;
        }
 
        (*_log_stream) << arg;
        return *this;
    }
 
    // Specializing for LogStreamEndLine to support slog::endl
    LogStream& operator<< (const LogStreamEndLine &/*arg*/) {
        _new_line = true;
 
        (*_log_stream) << std::endl;
        return *this;
    }
 
    // Specializing for LogStreamBoolAlpha to support slog::boolalpha
    LogStream& operator<< (const LogStreamBoolAlpha &/*arg*/) {
        (*_log_stream) << std::boolalpha;
        return *this;
    }
 
    // Specializing for std::vector and std::list
    template<template<class, class> class Container, class T>
    LogStream& operator<< (const Container<T, std::allocator<T>>& container) {
        for (const auto& el : container) {
            *this << el << slog::endl;
        }
        return *this;
    }
};
 
 
static LogStream info("INFO", std::cout);
static LogStream debug("DEBUG", std::cout);
static LogStream warn("WARNING", std::cout);
static LogStream err("ERROR", std::cerr);
 
}  // namespace slog