Deliver/include/String.Format.tlh

#pragma once


#ifndef ASSERT
#include <assert.h>
#define ASSERT assert
#endif


//-----------------------------------------------------------------------------
//	字符串格式化
//		思路主要来自祈宇的文章:
//	<实现一个简单的字符串格式化方法>
//	https://www.cnblogs.com/qicosmos/p/3825612.html
//-----------------------------------------------------------------------------


#include <tuple>
#include <type_traits>
#include <string>
#include <inttypes.h>
#include <cctype>
#include <stdexcept>
#include <codecvt>
#include <chrono>


#pragma warning (disable : 4996)
//warning C4996: 'strcpy': This function or variable may be unsafe. Consider using strcpy_s instead. 
// To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.


namespace ECOM::Utility::String
{
	template <typename>  constexpr bool dependent_false = false;

	template <typename T>
	inline std::string ToString (const T & value)
	{
		static_assert (dependent_false <T>, "You must implement ToString for type T with Partial template specialization !");
		return std::string ();
	}
}


// 针对 bool 的模板偏特化, 编译要求定义这些函数, 但是实际上不会执行
namespace ECOM::Utility::String
{
	template <> inline std::string ToString (const bool & value)
	{
		static const auto strTrue  = std::string ("true");
		static const auto strFalse = std::string ("false");
		if (value)  return strTrue;
		else  return strFalse;
	}

}


namespace ECOM::Utility::String
{

	static const char __MsgOfNull_ [] = "null";
	static const int  __LenOfNull_ = sizeof (__MsgOfNull_) - 1;

	template <typename tDeriveClass>
	class __declspec(novtable) _string_format_detail
	{
	protected:
		char * m_BufferOrg;
		char * m_Buffer;
		int    m_NbOfChar;

	protected:
		inline int  NbOfRemain () const
		{
			return m_NbOfChar - int (m_Buffer - m_BufferOrg);
		}

	private:
		template <typename arg>
		int _my_sprintf (char * buf, int NbOfChar, const char * fmt, arg a)
		{
			assert (false);
			return 22;
		}

	public:
		inline _string_format_detail (char * buf, int NbOfChar)	//	缓冲区指针, 缓冲区长度 (字节计数)
		{
			assert (buf);
			m_BufferOrg = m_Buffer = buf;
			m_NbOfChar = NbOfChar;
		}

	protected:
		inline void CharFormatArg (char ch)
		{
			// ch 不能是控制字符, 否则不知道显示成什么
			// assert (0  < ch);
			assert (9 <= ch);  assert (ch <= 127);

			*m_Buffer = ch;
			m_Buffer ++;
		}

		//	有符号
		template <typename T>
		inline void sDigitFormatArg (T i)
		{
			_ltoa (i, m_Buffer, 10);
			m_Buffer += strlen (m_Buffer);
		}

		// 无符号
		template <typename T>
		inline void uDigitFormatArg (T i)
		{
			_ultoa (i, m_Buffer, 10);
			m_Buffer += strlen (m_Buffer);
		}

		//<	64 位偏特化
		template <>
		inline void sDigitFormatArg (__int64 i)
		{
			_i64toa (i, m_Buffer, 10);
			m_Buffer += strlen (m_Buffer);
		}

		template <>
		inline void uDigitFormatArg (unsigned __int64 i)
		{
			_ui64toa (i, m_Buffer, 10);
			m_Buffer += strlen (m_Buffer);
		}
		//>

		template <typename T>
		//	fmt: D,X, D3,X4,d3,x4, D03,X04
		//	D   - 用 10 进制, X - 用 16 进制
		//	D3  - 转换成 3 个数字, 如果不足, 填充空格
		//	D03 - 转换成 3 个数字, 如果不足, 用 0 填充
		inline void DigitFormatArg (T i, const char * fmt)
		{
			assert (fmt);
			assert (fmt [0]);

			auto chfmt = fmt [0];

			if (chfmt == 'c' || chfmt == 'C')
			{
				CharFormatArg ((char) i);
				return;
			}

			if (chfmt == 'D')  chfmt = 'd';		//	把大写的 D 改成小写的 d, 因为 sprintf 不支持大写 D
			if (chfmt == 'U')  chfmt = 'u';		//	把大写的 U 改成小写的 u, 因为 sprintf 不支持大写 U
			auto rc = (chfmt == 'd' || chfmt == 'u' || chfmt == 'X' || chfmt == 'x');
			if (! rc)	//	尝试浮点数, 万一使用者搞错了
			{
				rc = (chfmt == 'f' || chfmt == 'F');
				if (rc)
				{
					FormatArg ((double) i, fmt);
					return;
				}
			}

			assert (rc);
			if (! rc)  return;					//	既不是 d, 也不是 u, 也不是 x, 也不是 c

			char tofmt [8] = { '%', };

			//	D023, X093 - 1 个格式字母带 3 个数字, tofmt 将成为 "%023d" 或 "%093x"

			//	最多支持 3 个数字. 注意, 如果判断到 \0 也不怕
			//	d1, d3 - 1 个格式字母带 1 个数字, tofmt 将成为 "%1d" 或 "%3d"
			if (std::isdigit (fmt [1]))
			{
				int iFmtChar = 2;
				for (int Index = 1; Index <= 3; Index ++)
				{
					if (std::isdigit (fmt [Index]))
					{
						tofmt [Index] = fmt [Index];
						iFmtChar = Index + 1;
					}
					else
						break;
				}

				tofmt [iFmtChar] = chfmt;
			}
			else //	只有 1 个 d, 比如写成 {$:d}
			{
				tofmt [1] = chfmt;
				tofmt [2] = 0;
			}

			auto pT = static_cast <tDeriveClass *> (this);
			auto r = pT->_my_sprintf (m_Buffer, NbOfRemain (), tofmt, i);
			m_Buffer += r;
		}

		//<	64 位偏特化
		template <>
		//	fmt: D,X, D3,X4,d3,x4, D03,X04
		//	__int64 只支持 d, x, 不支持前导/后导, 因此下面的代码只用了 D 或 X
		inline void DigitFormatArg (__int64 i, const char * fmt)
		{
			assert (fmt);
			assert (fmt [0]);

			auto chfmt = fmt [0];

			if (chfmt == 'c' || chfmt == 'C')
			{
				CharFormatArg ((char) i);
				return;
			}

			if (chfmt == 'D')  chfmt = 'd';		//	把大写的 D 改成小写的 d, 因为 sprintf 不支持大写 D
			if (chfmt == 'U')  chfmt = 'u';		//	把大写的 U 改成小写的 u, 因为 sprintf 不支持大写 U
			auto rc = (chfmt == 'd' || chfmt == 'u' || chfmt == 'X' || chfmt == 'x');
			assert (rc);
			if (! rc)  return;					//	既不是 d, 也不是 u, 也不是 x, 也不是 c

			char tofmt [8] = { '%', 'I', 'I', chfmt };

			auto pT = static_cast <tDeriveClass *> (this);
			auto r = pT->_my_sprintf (m_Buffer, NbOfRemain (), tofmt, i);

			m_Buffer += r;
		}

		//	64 位偏特化
		template <>
		//	fmt: D,X, D3,X4,d3,x4, D03,X04
		//	__int64 只支持 d, x, 不支持前导/后导, 因此下面的代码只用了 D 或 X
		inline void DigitFormatArg (unsigned __int64 i, const char * fmt)
		{
			DigitFormatArg <__int64> ((__int64) i, fmt);
		}
		//>


	//	字符,不带格式, 就认为是字符
		inline void FormatArg (char ch)				{ CharFormatArg (ch); }
//		inline void FormatArg (unsigned char ch)	{ CharFormatArg (ch); }
		inline void FormatArg (unsigned char ch)	{ uDigitFormatArg <unsigned short> (ch); }

	//	字符,带格式, 就认为是整数
		inline void FormatArg (char ch, const char * fmt) { DigitFormatArg <int> (ch, fmt); }
		inline void FormatArg (unsigned char ch, const char * fmt) { DigitFormatArg <int> (ch, fmt); }

	//< 各种整数
		inline void FormatArg (int i)				{ sDigitFormatArg <int>			  (i); }
		inline void FormatArg (long i)				{ sDigitFormatArg <long>			  (i); }
		inline void FormatArg (short i)				{ sDigitFormatArg <short>		  (i); }
		inline void FormatArg (unsigned int i)		{ uDigitFormatArg <unsigned int>   (i); }
		inline void FormatArg (unsigned long i)		{ uDigitFormatArg <unsigned long>  (i); }
		inline void FormatArg (unsigned short i)	{ uDigitFormatArg <unsigned short> (i); }

		inline void FormatArg (int i           , const char * fmt) { DigitFormatArg <int>				(i, fmt); }
		inline void FormatArg (unsigned int i  , const char * fmt) { DigitFormatArg <unsigned int>		(i, fmt); }
		inline void FormatArg (long i          , const char * fmt) { DigitFormatArg <long>				(i, fmt); }
		inline void FormatArg (unsigned long i , const char * fmt) { DigitFormatArg <unsigned long>		(i, fmt); }
		inline void FormatArg (short i         , const char * fmt) { DigitFormatArg <short>				(i, fmt); }
		inline void FormatArg (unsigned short i, const char * fmt) { DigitFormatArg <unsigned short>	(i, fmt); }

	//	int64
		inline void FormatArg (__int64 i)			{ sDigitFormatArg <__int64>			  (i); }
		inline void FormatArg (unsigned __int64 i)	{ uDigitFormatArg <unsigned __int64>   (i); }
	//	int64, 带参数
		inline void FormatArg (__int64 i          , const char * fmt) { DigitFormatArg <__int64>			(i, fmt); }
		inline void FormatArg (unsigned __int64 i , const char * fmt) { DigitFormatArg <unsigned __int64>	(i, fmt); }
	//>

	//< 浮点数, 默认精度由 printf 决定
		inline void FormatArg (double i)
		{
			auto pT = static_cast <tDeriveClass *> (this);
			auto r = pT->_my_sprintf (m_Buffer, NbOfRemain (), "%f", i);
			m_Buffer += r;
		}

		//	fmt: F3, 精确到小数点后面3位
		//	fmt: F, 默认精度由 printf 决定
		//	fmt : f}    --> tofmt : %f
		//	fmt : f3}   --> tofmt : %.3f
		//	fmt : f23}  --> tofmt : %.23f
		inline void FormatArg (double i, const char * fmt)
		{
			assert (fmt);
			assert (fmt [0]);

			char tofmt [8] = { '%', '.', };

			auto chfmt = fmt [0];

			//	最多支持 3 个数字. 注意, 如果判断到 \0 也不怕
			//	f1, f3 - 1 个格式字母带 1 个数字, tofmt 将成为 "%.1f" 或 "%.3f"
			if (std::isdigit (fmt [1]))
			{
				int iFmtChar = 2;
				for (int Index = 1; Index <= 3; Index ++)
				{
					if (std::isdigit (fmt [Index]))
					{
						tofmt [Index+1] = fmt [Index];
						iFmtChar = Index + 2;
					}
					else
						break;
				}

				tofmt [iFmtChar] = chfmt;
			}
			else //	只有 1 个 f, 比如写成 {$:f}
			{
				tofmt [1] = chfmt;
				tofmt [2] = 0;
			}

			auto pT = static_cast <tDeriveClass *> (this);
			auto r = pT->_my_sprintf (m_Buffer, NbOfRemain (), tofmt, i);
			m_Buffer += r;
		}

		inline void FormatArg (float f)
		{
			double d = f;
			FormatArg (d);
		}

		inline void FormatArg (float f, const char * fmt)
		{
			double d = f;
			FormatArg (d, fmt);
		}
	//>

	//	字符串, 无格式
		inline void FormatArg (const char * p)
		{
			if (p == nullptr)
			{
				memcpy (m_Buffer, __MsgOfNull_, __LenOfNull_);
				m_Buffer += __LenOfNull_;
				return;
			}

			int len = (int) strlen (p);
			memcpy (m_Buffer, p, len);
			m_Buffer += len;
		}

	//<	字符串, 带格式, 格式:
	//	6  : 最长 6 个字符, 右对齐, 左边填空
	//	+6 : 最长 6 个字符, 右对齐, 左边填空
	//	-6 : 最长 6 个字符, 左对齐, 右边填空
		inline void FormatArg (const char * p, const char * fmt)
		{
			if (p == nullptr)
			{
				memcpy (m_Buffer, __MsgOfNull_, __LenOfNull_);
				m_Buffer += __LenOfNull_;
				return;
			}

			int len = (int) strlen (p);

			_StringFormatArg (p, len, fmt);
		}

		inline void FormatArg (char * p)
		{
			FormatArg ((const char *) p);
		}

		inline void FormatArg (char * p, const char * fmt)
		{
			FormatArg ((const char *)p, fmt);
		}


		inline void _StringFormatArg (const char * p, int len, const char * fmt)
		{
			if (p == nullptr)
			{
				memcpy (m_Buffer, __MsgOfNull_, __LenOfNull_);
				m_Buffer += __LenOfNull_;
				return;
			}

			if (fmt [0] == '-')		//	左对齐
			{
				fmt ++;
				auto i = atoi (fmt);
				if (i > len)
				{
					memcpy (m_Buffer, p, len);
					m_Buffer += len;
					memset (m_Buffer, ' ', i - len);
					m_Buffer += i - len;
				}
				else
				{
					memcpy (m_Buffer, p, len);
					m_Buffer += len;
				}
			}
			else					//	右对齐
			{
				if (fmt [0] == '+')  fmt ++;

				auto i = atoi (fmt);
				if (i > len)
				{
					memset (m_Buffer, ' ', i - len);
					m_Buffer += i - len;
					memcpy (m_Buffer, p, len);
					m_Buffer += len;
				}
				else
				{
					memcpy (m_Buffer, p, len);
					m_Buffer += len;
				}
			}
		}
	//>

	//	bool
		void FormatArg (bool b)
		{
			if (b)
			{
				*m_Buffer = 't';  m_Buffer ++;
				*m_Buffer = 'r';  m_Buffer ++;
				*m_Buffer = 'u';  m_Buffer ++;
				*m_Buffer = 'e';  m_Buffer ++;
			}
			else
			{
				*m_Buffer = 'f';  m_Buffer ++;
				*m_Buffer = 'a';  m_Buffer ++;
				*m_Buffer = 'l';  m_Buffer ++;
				*m_Buffer = 's';  m_Buffer ++;
				*m_Buffer = 'e';  m_Buffer ++;
			}
		}

	//	任意指针类型 - const
		template <typename UNP>
		inline void FormatArg (const UNP * ptr)
		{
			auto pT = static_cast <tDeriveClass *> (this);
			auto r = pT->_my_sprintf (m_Buffer, NbOfRemain (), "%p", ptr);
			m_Buffer += r;
		}

	//	任意指针类型, 带格式 -- 转化成整数来格式化
		template <typename UNP>
		inline void FormatArg (const UNP * ptr, const char * fmt)
		{
			DigitFormatArg <uintptr_t> ((uintptr_t) ptr, fmt);
		}


		//	任意指针类型 - 非 const
		template <typename UNP>
		inline void FormatArg (UNP * ptr)
		{
			auto pT = static_cast <tDeriveClass *> (this);
			auto r = pT->_my_sprintf (m_Buffer, NbOfRemain (), "%p", ptr);
			m_Buffer += r;
		}

		//	任意指针类型, 带格式 -- 转化成整数来格式化
		template <typename UNP>
		inline void FormatArg (UNP * ptr, const char * fmt)
		{
			DigitFormatArg <uintptr_t> ((uintptr_t)ptr, fmt);
		}


	//	偏特化 - 字符串指针
		template <> inline void FormatArg (const char * p)
		{
			if (p == nullptr)
			{
				memcpy (m_Buffer, __MsgOfNull_, __LenOfNull_);
				m_Buffer += __LenOfNull_;
				return;
			}

			int len = (int) strlen (p);
			memcpy (m_Buffer, p, len);
			m_Buffer += len;
		}

	//	偏特化 - 字符串指针
		template <> inline void FormatArg (const char * p, const char *)
		{
			if (p == nullptr)
			{
				memcpy (m_Buffer, __MsgOfNull_, __LenOfNull_);
				m_Buffer += __LenOfNull_;
				return;
			}

			int len = (int) strlen (p);
			memcpy (m_Buffer, p, len);
			m_Buffer += len;
		}

	protected:

//<	string_view
		inline void FormatArg (const std::string_view & s)
		{
			memcpy (m_Buffer, s.data (), s.size ());
			m_Buffer += s.size ();
		}

		inline void FormatArg (const std::string_view & s, const char * fmt)
		{
			_StringFormatArg (s.data (), static_cast <int> (s.size ()), fmt);
		}


		inline void FormatArg (const std::wstring_view & s)
		{
			std::wstring_convert <std::codecvt <wchar_t, char, mbstate_t>> converter;
			auto str = converter.to_bytes (s.data (), s.data () + s.size ());
			FormatArg (str);
		}

		inline void FormatArg (const std::wstring_view & s, const char * fmt)
		{
			std::wstring_convert <std::codecvt <wchar_t, char, mbstate_t>> converter;
			auto str = converter.to_bytes (s.data (), s.data () + s.size ());
			FormatArg (str, fmt);
		}
//>


	#ifdef __Utility_String_StringView__
		inline void FormatArg (const DStringView & s)
		{
			memcpy (m_Buffer, s.constBuffer (), s.Length ());
			m_Buffer += s.Length ();
		}

		inline void FormatArg (const DStringView & s, const char * fmt)
		{
			_StringFormatArg (s.constBuffer (), s.Length (), fmt);
		}

	#endif


	#ifdef DSTRING_API
		inline void FormatArg (const DString & s)
		{
			memcpy (m_Buffer, s.constBuffer (), s.GetLength ());
			m_Buffer += s.GetLength ();
		}

		inline void FormatArg (const DString & s, const char * fmt)
		{
			_StringFormatArg (s.constBuffer (), s.GetLength (), fmt);
		}
	#endif

//< std::string
		inline void FormatArg (const std::string & s)
		{
			memcpy (m_Buffer, s.data (), s.size ());
			m_Buffer += s.size ();
		}

		inline void FormatArg (const std::string & s, const char * fmt)
		{
			_StringFormatArg (s.data (), (int) s.size (), fmt);
		}
//>

	#ifdef WSTRING_API
	//#if 1

		inline void FormatArg (const wchar_t * p)
		{
			if (p == nullptr)
			{
				memcpy (m_Buffer, __MsgOfNull_, __LenOfNull_);
				m_Buffer += __LenOfNull_;
				return;
			}

			auto dp = WString (WStringView (p)).ToDString ();
			FormatArg (dp);
		}

		inline void FormatArg (const wchar_t * p, const char * fmt)
		{
			if (p == nullptr)
			{
				memcpy (m_Buffer, __MsgOfNull_, __LenOfNull_);
				m_Buffer += __LenOfNull_;
				return;
			}

			auto dp = WString (WStringView (p)).ToDString ();
			FormatArg (dp, fmt);
		}

		inline void FormatArg (const WString & s)
		{
			auto dp = s.ToDString ();
			FormatArg (dp);
		}

		inline void FormatArg (const WString & s, const char * fmt)
		{
			auto dp = s.ToDString ();
			FormatArg (dp, fmt);
		}

		inline void FormatArg (const std::wstring & s)
		{
			auto dp = WString (s.c_str ()).ToDString ();
			FormatArg (dp);
		}

		inline void FormatArg (const std::wstring & s, const char * fmt)
		{
			auto dp = WString (s.c_str ()).ToDString ();
			FormatArg (dp, fmt);
		}

		inline void FormatArg (const WStringView & ws)
		{
			auto ds = WString (ws).ToDString ();
			FormatArg (ds);
		}

		inline void FormatArg (const WStringView & ws, const char * fmt)
		{
			auto ds = WString (ws).ToDString ();
			FormatArg (ds, fmt);
		}

	#endif


#if 1
		template <typename TO>
		inline void FormatArg (const TO & _val)
		{
			auto dp = ECOM::Utility::String::ToString <TO> (_val);
			FormatArg (dp);
		}

		template <typename TO>
		inline void FormatArg (const TO & _val, const char * fmt)
		{
			auto dp = ECOM::Utility::String::ToString <TO> (_val);
			FormatArg (dp, fmt);
		}
#endif


	protected:
		template <size_t k, typename Tuple>
		typename std::enable_if <(k == std::tuple_size <Tuple>::value)>::type
		inline GetArgByIndex (size_t, Tuple &)
		{
	//	忽略那些误写的位置参数, 比如忽略下面的 {99}
	//	mLog::Info ("{99}, {0}", 123456
	#ifdef _DEBUG
	//				throw std::invalid_argument ("arg index out of range");
	#endif
		}

		template <size_t k = 0, typename Tuple>
		typename std::enable_if <(k < std::tuple_size <Tuple>::value)>::type
		inline GetArgByIndex (size_t index, Tuple & tp)
		{
			if (k == index)
			{
				FormatArg (std::get<k> (tp));
			}
			else
			{
				GetArgByIndex <k + 1> (index, tp);
			}
		}


		template <size_t k, typename Tuple>
		typename std::enable_if <(k == std::tuple_size <Tuple>::value)>::type
		inline GetArgByIndex (size_t, Tuple &, const char * fmt)
		{
	#ifdef _DEBUG
	//				throw std::invalid_argument ("arg index out of range");
	#endif
		}

		template <size_t k = 0, typename Tuple>
		typename std::enable_if <(k < std::tuple_size <Tuple>::value)>::type
		inline GetArgByIndex (size_t index, Tuple & tp, const char * fmt)
		{
			if (k == index)
			{
				FormatArg (std::get <k> (tp), fmt);
			}
			else
			{
				GetArgByIndex <k + 1> (index, tp, fmt);
			}
		}

		static inline const char * FirstDollar (const char *& p)
		{
			while (*p != '}' && *p != '\0')
			{
				if ('$' == (*p))
					return p;
				p ++;
			}

			return nullptr;
		}

		static inline const char * FirstDigit (const char *& p)
		{
			while (*p != '}' && *p != '\0')
			{
				if (std::isdigit (*p))
					return p;
				p ++;
			}

			return nullptr;
		}

		static inline const char * LastDigit (const char *& p)
		{
			while (*p != '}' && *p != '\0')
			{
				if (! std::isdigit (*p))
					return p - 1;
				p ++;
			}

			return p - 1;
		}

		static inline const char * FindColon (const char *& p)
		{
			while (*p != '}' && *p != '\0')
			{
				if (*p == ':')
					return p;
				p++;
			}

			return nullptr;
		}

		static inline const char * FindRightBrace (const char *& p)
		{
			while (*p != '\0')
			{
				if (*p == '}')
					return p;
				p++;
			}

			return nullptr;
		}

		static inline int GetIndex (const char *& p, const char *& fmt, int prevIndex)
		{
			auto bp = p;	//	备份一下, 因为后面跟的可能是 $, 也可能是数字

			auto pDollar = FirstDollar (p);
			if (pDollar)
			{
				auto pc = FindColon (p);
				auto _  = FindRightBrace (p);
				if (pc)
					fmt = pc + 1;
				return prevIndex + 1;
			}

			p = bp;
			auto pd = FirstDigit     (p);
			auto pl = LastDigit      (p);
			auto pc = FindColon      (p);
			auto _  = FindRightBrace (p);

			if (pd == nullptr)  return -1;

			auto ii = pl + 1 - pd;
			assert (ii <= 2);
			if (ii <= 0)  return -1;

			char temp [3] = {};
			temp [0] = *pd; pd ++;
			temp [1] = *pd;
			auto index = std::atoi (temp);

			if (pc)
				fmt = pc + 1;

			return index;
		}

	public:
	//	返回: 格式化后的字符串长度
		template <typename... Args>
		inline int  Format (const char * fmt, Args && ... args)
		{
			int  fmtlen = (int) strlen (fmt);
			return DoFormat (fmtlen, fmt, std::forward <Args> (args)...);
		}

#ifdef __Utility_String_StringView__
		template <typename... Args>
		inline int  Format (const eSTR::StringView & fmt, Args && ... args)
		{
			int  fmtlen = fmt.GetLength ();
			return DoFormat (fmtlen, fmt, std::forward <Args> (args)...);
		}
#endif

		template <typename... Args>
		inline int  Format (const std::string_view & fmt, Args && ... args)
		{
			int  fmtlen = static_cast <int> (fmt.size ());
			return DoFormat (fmtlen, fmt, std::forward <Args> (args)...);
		}

	protected:
		template <typename... Args>
		inline int  DoFormat (int fmtlen, const char * fmt, Args && ... args)
		{
			assert (fmt);
			if (fmt == nullptr)
			{
				m_Buffer [0] = 0;
				return 0;
			}

			//	最好在上层判断, 以避免在这里重复计算 strlen
			if (sizeof...(args) == 0)
			{
				strcpy (m_Buffer, fmt);
				return fmtlen;
			}

			auto tp = std::tuple <Args...> (std::forward <Args> (args)...);
			return DoFormat (fmtlen, fmt, std::move (tp));
		}

		template <typename... Args>
		inline int  DoFormat (int fmtlen, const char * fmt, std::tuple <Args ...> && tp)
		{
			assert (fmt);
			if (fmt == nullptr)
			{
				m_Buffer [0] = 0;
				return 0;
			}

			m_Buffer = m_BufferOrg;

			const char * p = fmt;
			const char * original = p;
			int  len   = fmtlen + 1;
			int  last  = 0;
			int  Index = -1;
			while (true)
			{
				if (*p == '{')
				{
					//copy content befor {
					last = int (p - original);
					if (last)
					{
						memcpy (m_Buffer, original, last);
						m_Buffer += last;
					}

					//format args
					const char * tmp = nullptr;
					Index = GetIndex (p, tmp, Index);
					if (Index >= 0)
					{
						if (tmp)
							GetArgByIndex <0> (Index, tp, tmp);
						else
							GetArgByIndex <0> (Index, tp);
					}

					//skip }
					original = p + 1;
				}
				else
				if (*p == '\0')
				{
					last = int (p - original);
					if (last == 0)
						*m_Buffer = 0;
					else
					{
						memcpy (m_Buffer, original, last + 1);	//	+1 的目的是, 包括尾部的 \0
						m_Buffer += last;
					}
					break;
				}

				p++;
			}

			auto delta = m_Buffer - m_BufferOrg;

	#ifdef _DEBUG
			len = (int) strlen (m_BufferOrg);
			assert ((delta - len) == 0);
			// ! 此断言对以下语句不成立:
			//   char ch = 0;  mLog::Info ("{$}", ch);
			//   应改成以下语句, 即强制作为数字
			//   char ch = 0;  mLog::Info ("{$:d2}", ch);
	#endif

			return (int) delta;
	//		return buf_org;
		}

	};



	class StringFormat : public _string_format_detail <StringFormat>
	{
	public:
		inline StringFormat (char * buf, int NbOfChar) : _string_format_detail (buf, NbOfChar) { }

	public:
		template <typename arg>
		inline int _my_sprintf (char * buf, int NbOfChar, const char * fmt, arg a)
		{
			return sprintf_s (buf, NbOfChar, fmt, a);
		}
	};



}




//-----------------------------------------------------------------------------
//		设计说明 (2021-06-18):
//  1. 为什么只能支持 3 个数字 (即 最大只能是 {$:d999} 或 {$:f999})
//     1) 预留的 Buffer 一般大小是 8192, 见 DString::Format 及 TLSLog
//     2) 最终会调用 _vsprintf_s_l (buffer, len, ...)
//     3) 当 buffer 不足时, 上述函数会调用 无效参数错误处理函数, 
//     4) 无效参数错误处理函数 : 在 Debug 模式时, 弹出断言错误. 在 Release 模式时, 直接终止程序.
//
//-----------------------------------------------------------------------------


//-----------------------------------------------------------------------------
//		自定义类型的格式化 (2023-05-15)

/*
class TestMyClass
{
public:
	TestMyClass () = default;
};

namespace ECOM::Utility::String
{
	template <> inline std::string ToString (const TestMyClass & value)
	{
		return std::string ("it is TestMyClass !");
	}
}
*/

// assert (eSTR::DString::FromFormat ("{$}{$}-{$}"_sv, 11, 22, TestMyClass ()) == eSTR::DString ("1122-it is TestMyClass !"));

//-----------------------------------------------------------------------------