C++ リハビリ勉強中。コンソール出力において属性（文字色や背景色）を指定可能なマニピュレーターを実装してみる。

put_attr.h

#pragma once

#include <iostream>

using namespace std;


//
// コンソール出力において属性（文字色や背景色）を指定可能なマニピュレーターを実装します。
//
// put_time() や put_money() のスタイルを真似ています。
//

template <class _Elem> class put_attr_t
{
	const _Elem *text;

	const int attr;

public:
	put_attr_t(const _Elem *t, const int a) : text(t), attr(a)
	{
	}

	basic_ostream<_Elem, char_traits<_Elem>> &put(basic_ostream<_Elem, char_traits<_Elem>> &os) const;
};

const put_attr_t<char> put_attr(const char *text, int attr)
{
	return put_attr_t<char>(text, attr);
}

const put_attr_t<wchar_t> put_attr(const wchar_t *text, int attr)
{
	return put_attr_t<wchar_t>(text, attr);
}

const put_attr_t<char> put_attr(const string &text, int attr)
{
	return put_attr_t<char>(text.c_str(), attr);
}

const put_attr_t<wchar_t> put_attr(const wstring &text, int attr)
{
	return put_attr_t<wchar_t>(text.c_str(), attr);
}

template<class _Elem> basic_ostream<_Elem, char_traits<_Elem>> &operator<<(basic_ostream<_Elem, char_traits<_Elem>> &os, const put_attr_t<_Elem> &attr)
{
	return attr.put(os);
}


//
// Windows 専用の実装です。 http://msdn.microsoft.com/ja-jp/library/cc429756.aspx を参照してください。
//

#if _WIN32

#include <windows.h>

extern const unsigned long std_out_handle = STD_OUTPUT_HANDLE;
extern const unsigned long std_err_handle = STD_ERROR_HANDLE;

extern const int red = FOREGROUND_INTENSITY | FOREGROUND_RED;
extern const int blue = FOREGROUND_INTENSITY | FOREGROUND_BLUE;
extern const int green = FOREGROUND_INTENSITY | FOREGROUND_GREEN;

class text_attribute
{
	HANDLE hConsoleOutput;

	CONSOLE_SCREEN_BUFFER_INFO csbi;

public:
	text_attribute(unsigned long out, int attr)
	{
		if ((hConsoleOutput = ::GetStdHandle(out)) != INVALID_HANDLE_VALUE)
		{
			if (::GetConsoleScreenBufferInfo(hConsoleOutput, &csbi))
			{
				::SetConsoleTextAttribute(hConsoleOutput, attr & 0xFFFF);
			}
			else
			{
				csbi.wAttributes = 0;
			}
		}
	}

	~text_attribute()
	{
		if (hConsoleOutput != INVALID_HANDLE_VALUE && csbi.wAttributes != 0)
		{
			::SetConsoleTextAttribute(hConsoleOutput, csbi.wAttributes);
		}
	}
};

#endif


//
// 汎用になりそうなテンプレート部分です。とりあえず、この段階で cout, cerr, wcout, wcerr を見ています。
//

template <class _Elem> basic_ostream<_Elem, char_traits<_Elem>> &put_attr_t<_Elem>::put(basic_ostream<_Elem, char_traits<_Elem>> &os) const
{
	if (os == cout || os == wcout)
	{
		text_attribute attribute(std_out_handle, attr);

		return os << text;
	}

	if (os == cerr || os == wcerr)
	{
		text_attribute attribute(std_err_handle, attr);

		return os << text;
	}

	return os << text;
}

こんな感じで使えるはず。

#include <iostream>

#include "put_attr.h"

using namespace std;

int main() 
{
    // "const char *" を cout へ出力
    cout << "testing" << put_attr(" testing ", red) << "testing" << endl;
    cout << "testing" << put_attr(" testing ", blue) << "testing" << endl;
    cout << "testing" << put_attr(" testing ", green) << "testing" << endl;

    // "const wchar_t *" を wcout へ出力
    wcout << "testing" << put_attr(L" testing ", red) << "testing" << endl;
    wcout << "testing" << put_attr(L" testing ", blue) << "testing" << endl;
    wcout << "testing" << put_attr(L" testing ", green) << "testing" << endl;

    // std::string を cout へ出力
    string testing = " testing ";
    cout << "testing" << put_attr(testing, red) << "testing" << endl;
    cout << "testing" << put_attr(testing, blue) << "testing" << endl;
    cout << "testing" << put_attr(testing, green) << "testing" << endl;

    // std::wstring を wcout へ出力
    wstring wtesting = L" testing ";
    wcout << "testing" << put_attr(wtesting, red) << "testing" << endl;
    wcout << "testing" << put_attr(wtesting, blue) << "testing" << endl;
    wcout << "testing" << put_attr(wtesting, green) << "testing" << endl;
}