#include "stdafx.h"
#include "Bstring.h"
#include "string.h"


//typedef char				TCHAR;
//typedef const TCHAR FAR *	LPCTSTR;


BYTE afxChNil = '\0';

int _afxInitData[] = { -1, 0, 0, 0 }; //初始化BStringData的地址

BStringData* _afxDataNil = (BStringData*)&_afxInitData; //地址转化为BStringData*

LPBTSTR _afxPchNil = (LPBTSTR)(((BYTE*)&_afxInitData)+sizeof(BStringData));

const BString& AfxGetEmptyString() //建立一个空的BString
{ 
	return *(BString*)&_afxPchNil; 
}

BOOL AfxIsValidString(LPBTSTR lpsz, int nLength /* = -1 */)
{
	if (lpsz == NULL)
		return FALSE;
	return ::IsBadStringPtr(reinterpret_cast<LPCTSTR>(lpsz), nLength) == 0;
}

BOOL AfxIsValidAddress(const void* lp, UINT nBytes,BOOL bReadWrite /* = TRUE */)
{
	return (lp != NULL && !IsBadReadPtr(lp, nBytes) &&	(!bReadWrite !IsBadWritePtr((LPVOID)lp, nBytes)));
}

void BString::Init()
{ 
	m_pchData=AfxGetEmptyString().m_pchData; 
}

BString::BString()
{ 
	Init(); 
}

int BString::GetLength() const
{ 
	return GetData()->nDataLength; 
}

int BString::GetAllocLength() const
{ 
	return GetData()->nAllocLength; 
}

BOOL BString::IsEmpty() const
{ 
	return GetData()->nDataLength == 0; 
}

BStringData* BString::GetData() const
{
	assert(m_pchData != NULL);
	return ((BStringData*)m_pchData)-1;
}

BString::operator LPBTSTR() const
{ 
	return m_pchData; 
}

int BString::SafeStrlen(LPBTSTR lpsz)
{ 
	return (lpsz == NULL) ? 0 : lstrlen(reinterpret_cast<LPCTSTR>(lpsz)); 
}

void BString::AllocBuffer(int nLen)
{
	assert(nLen >= 0);
	assert(nLen <= 2147483647-1); // (signed) int 的最大值
	if (nLen == 0)
		Init();
	else
	{
		BStringData* pData;
		{
			pData = (BStringData*)
				new BYTE[sizeof(BStringData) + (nLen+1)*sizeof(TCHAR)];
			pData->nAllocLength = nLen;
		}
		pData->nRefs = 1;
		pData->data()[nLen] = '\0';
		pData->nDataLength = nLen;
		m_pchData = pData->data();
	}
}

void BString::FreeData(BStringData* pData)
{
	delete[] (BYTE*)pData;
}
void BString::CopyBeforeWrite()
{
	if (GetData()->nRefs > 1)
	{
		BStringData* pData = GetData();
		Release();
		AllocBuffer(pData->nDataLength);
		memcpy(m_pchData, pData->data(), (pData->nDataLength+1)*sizeof(BYTE));
	}
	assert(GetData()->nRefs <= 1);
}
void BString::AllocBeforeWrite(int nLen)
{
	if (GetData()->nRefs > 1 && nLen > GetData()->nAllocLength)
	{
		Release();
		AllocBuffer(nLen);
	}
	assert(GetData()->nRefs <= 1);
}
void BString::AssignCopy(int nSrcLen, LPBTSTR lpszSrcData)
{
	AllocBeforeWrite(nSrcLen);
	memcpy(m_pchData, lpszSrcData, nSrcLen*sizeof(BYTE));
	GetData()->nDataLength = nSrcLen;
	m_pchData[nSrcLen] = '\0';
}
void BString::AllocCopy(BString& dest, int nCopyLen, int nCopyIndex,
						int nExtraLen) const
{
	int nNewLen = nCopyLen + nExtraLen;
	if (nNewLen == 0)
	{
		dest.Init();
	}
	else
	{
		dest.AllocBuffer(nNewLen);
		memcpy(dest.m_pchData, m_pchData+nCopyIndex, nCopyLen*sizeof(BYTE));
	}
}
BString::~BString()
{
	if (GetData() != _afxDataNil)
	{
		if (InterlockedDecrement(&GetData()->nRefs) <= 0)
			FreeData(GetData());
	}
}
BString::BString(const BString& stringSrc)
{
	assert(stringSrc.GetData()->nRefs != 0);
	if (stringSrc.GetData()->nRefs >= 0)
	{
		assert(stringSrc.GetData() != _afxDataNil);
		m_pchData = stringSrc.m_pchData;
		InterlockedIncrement(&GetData()->nRefs);
	}
	else
	{
		Init();
		*this = stringSrc.m_pchData;
	}
}
BString::BString(LPBTSTR lpsz)
{
	Init();
	int nLen = SafeStrlen(lpsz);
	if (nLen != 0)
	{
		AllocBuffer(nLen);
		memcpy(m_pchData, lpsz, nLen*sizeof(BYTE));
	}
}
BString::BString(LPBTSTR lpch, int nLength)
{
	Init();
	if (nLength != 0)
	{
		assert(AfxIsValidAddress(lpch, nLength, FALSE));
		AllocBuffer(nLength);
		memcpy(m_pchData, lpch, nLength*sizeof(BYTE));
	}
}
void BString::Release()
{
	if (GetData() != _afxDataNil)
	{
		assert(GetData()->nRefs != 0);
		if (InterlockedDecrement(&GetData()->nRefs) <= 0)
			FreeData(GetData());
		Init();
	}
}
void BString::Release(BStringData* pData)
{
	if (pData != _afxDataNil)
	{
		assert(pData->nRefs != 0);
		if (InterlockedDecrement(&pData->nRefs) <= 0)
			FreeData(pData);
	}
}
void BString::Empty()
{
	if (GetData()->nDataLength == 0)
		return;
	if (GetData()->nRefs >= 0)
		Release();
	else
		*this = &afxChNil;
	assert(GetData()->nDataLength == 0);
	assert(GetData()->nRefs < 0 GetData()->nAllocLength == 0);
}
const BString& BString::operator=(const BString& stringSrc)
{
	if (m_pchData != stringSrc.m_pchData)
	{
		if ((GetData()->nRefs < 0 && GetData() != _afxDataNil) && stringSrc.GetData()->nRefs < 0)
		{
			//新建一快数据
			AssignCopy(stringSrc.GetData()->nDataLength, stringSrc.m_pchData);
		}
		else
		{
			//只拷贝指针
			Release();
			assert(stringSrc.GetData() != _afxDataNil);
			m_pchData = stringSrc.m_pchData;
			InterlockedIncrement(&GetData()->nRefs);
		}
	}
	return *this;
}
const BString& BString::operator=(LPBTSTR lpsz)
{
	assert(lpsz == NULL AfxIsValidString(lpsz));
	AssignCopy(SafeStrlen(lpsz), lpsz);
	return *this;
}
const BString& BString::operator=(BYTE ch)
{
	AssignCopy(1, &ch);
	return *this;
}
int BString::Delete(int nIndex, int nCount /* = 1 */)
{
	if (nIndex < 0)
		nIndex = 0;
	int nNewLength = GetData()->nDataLength;
	if (nCount > 0 && nIndex < nNewLength)
	{
		CopyBeforeWrite(); //脱离共享数据块，
		int nBytesToCopy = nNewLength - (nIndex + nCount) + 1;
		//移动数据
		memcpy(m_pchData + nIndex,
			m_pchData + nIndex + nCount, nBytesToCopy * sizeof(BYTE));
		GetData()->nDataLength = nNewLength - nCount;
	}
	return nNewLength;
}
int BString::Insert(int nIndex, BYTE ch)
{
	CopyBeforeWrite(); //脱离共享数据
	if (nIndex < 0)
		nIndex = 0;
	int nNewLength = GetData()->nDataLength;
	if (nIndex > nNewLength)
		nIndex = nNewLength;
	nNewLength++;
	if (GetData()->nAllocLength < nNewLength)
	{ //动态分配内存,并拷贝原来的数据
		BStringData* pOldData = GetData();
		BYTE* pstr = m_pchData;
		AllocBuffer(nNewLength);
		memcpy(m_pchData, pstr, (pOldData->nDataLength+1)*sizeof(BYTE));
		BString::Release(pOldData);
	}
	//插入数据
	memcpy(m_pchData + nIndex + 1,
		m_pchData + nIndex, (nNewLength-nIndex)*sizeof(BYTE));
	m_pchData[nIndex] = ch;
	GetData()->nDataLength = nNewLength;
	return nNewLength;
}
int BString::Insert(int nIndex, LPBTSTR pstr)
{
	if (nIndex < 0)
		nIndex = 0;
	int nInsertLength = SafeStrlen(pstr);
	int nNewLength = GetData()->nDataLength;
	if (nInsertLength > 0)
	{
		CopyBeforeWrite(); //脱离共享数据
		if (nIndex > nNewLength)
			nIndex = nNewLength;
		nNewLength += nInsertLength;
		if (GetData()->nAllocLength < nNewLength)
		{ //动态分配内存,并拷贝原来的数据
			BStringData* pOldData = GetData();
			BYTE* pstr = m_pchData;
			AllocBuffer(nNewLength);
			memcpy(m_pchData, pstr, (pOldData->nDataLength+1)*sizeof(BYTE));
			BString::Release(pOldData);
		}
		//移动数据，留出插入的位酒move也可以
		memcpy(m_pchData + nIndex + nInsertLength,
			m_pchData + nIndex,
			(nNewLength-nIndex-nInsertLength+1)*sizeof(BYTE));
		//插入数据
		memcpy(m_pchData + nIndex,
			pstr, nInsertLength*sizeof(BYTE));
		GetData()->nDataLength = nNewLength;
	}
	return nNewLength;
}
int BString::Replace(BYTE chOld, BYTE chNew)
{
	int nCount = 0;
	if (chOld != chNew) //替换的不能相同
	{
		CopyBeforeWrite();
		BYTE* psz = m_pchData;
		BYTE* pszEnd = psz + GetData()->nDataLength;
		while (psz < pszEnd)
		{
			if (*psz == chOld) //替换
			{
				*psz = chNew;
				nCount++;
			}
			psz = _tcsinc(psz); //相当于++psz,考虑要UNICODE下版本才用的
		}
	}
	return nCount;
}
int BString::Replace(LPBTSTR lpszOld, LPBTSTR lpszNew)
{
	int nSourceLen = SafeStrlen(lpszOld);
	if (nSourceLen == 0) //要替换的不能为空
		return 0;
	int nReplacementLen = SafeStrlen(lpszNew);
	int nCount = 0;
	LPTSTR lpszStart = m_pchData;
	LPTSTR lpszEnd = m_pchData + GetData()->nDataLength;
	LPTSTR lpszTarget;
	while (lpszStart < lpszEnd) //检索要替换的个数
	{
		while ((lpszTarget = _tcsstr(reinterpret_cast<LPCTSTR>(lpszStart), reinterpret_cast<LPCTSTR>(lpszOld))) != NULL)
		{
			nCount++;
			lpszStart = lpszTarget + nSourceLen;
		}
		lpszStart += lstrlen(lpszStart) + 1;
	}
	if (nCount > 0)
	{
		CopyBeforeWrite();
		int nOldLength = GetData()->nDataLength;
		int nNewLength = nOldLength + (nReplacementLen-nSourceLen)*nCount; //替换以后的长度
		if (GetData()->nAllocLength < nNewLength GetData()->nRefs > 1)
		{ //超出原来的内存长度动态分配
			BStringData* pOldData = GetData();
			LPTSTR pstr = m_pchData;
			AllocBuffer(nNewLength);
			memcpy(m_pchData, pstr, pOldData->nDataLength*sizeof(BYTE));
			BString::Release(pOldData);
		}
		lpszStart = m_pchData;
		lpszEnd = m_pchData + GetData()->nDataLength;
		while (lpszStart < lpszEnd) //这个循环好象没什么用
		{
			while ( (lpszTarget = _tcsstr(lpszStart, lpszOld)) != NULL) //开始替换
			{
				int nBalance = nOldLength - (lpszTarget - m_pchData + nSourceLen); //要往后移的长度
				//移动数据，留出插入的位酒
				memmove(lpszTarget + nReplacementLen, lpszTarget + nSourceLen,
					nBalance * sizeof(BYTE));
				//插入替换数据
				memcpy(lpszTarget, lpszNew, nReplacementLen*sizeof(BYTE));
				lpszStart = lpszTarget + nReplacementLen;
				lpszStart[nBalance] = '\0';
				nOldLength += (nReplacementLen - nSourceLen); //现有数据长度
			}
			lpszStart += lstrlen(lpszStart) + 1;
		}
		assert(m_pchData[nNewLength] == '\0');
		GetData()->nDataLength = nNewLength;
	}
	return nCount;
}
int BString::Remove(BYTE chRemove)
{
	CopyBeforeWrite();
	LPTSTR pstrSource = m_pchData;
	LPTSTR pstrDest = m_pchData;
	LPTSTR pstrEnd = m_pchData + GetData()->nDataLength;
	while (pstrSource < pstrEnd)
	{
		if (*pstrSource != chRemove)
		{
			*pstrDest = *pstrSource; //把不移除的数据拷贝
			pstrDest = _tcsinc(pstrDest);
		}
		pstrSource = _tcsinc(pstrSource);//++pstrSource
	}
	*pstrDest = '\0';
	int nCount = pstrSource - pstrDest; //比较变态的计算替换个数,
	GetData()->nDataLength -= nCount;
	return nCount;
}
BString BString::Mid(int nFirst) const
{
	return Mid(nFirst, GetData()->nDataLength - nFirst);
}
BString BString::Mid(int nFirst, int nCount) const
{
	if (nFirst < 0)
		nFirst = 0;
	if (nCount < 0)
		nCount = 0;
	if (nFirst + nCount > GetData()->nDataLength)
		nCount = GetData()->nDataLength - nFirst;
	if (nFirst > GetData()->nDataLength)
		nCount = 0;
	assert(nFirst >= 0);
	assert(nFirst + nCount <= GetData()->nDataLength);
	//取去整个数据
	if (nFirst == 0 && nFirst + nCount == GetData()->nDataLength)
		return *this;
	BString dest; 
	AllocCopy(dest, nCount, nFirst, 0);
	return dest;
}
BString BString::Right(int nCount) const
{
	if (nCount < 0)
		nCount = 0;
	if (nCount >= GetData()->nDataLength)
		return *this;
	BString dest;
	AllocCopy(dest, nCount, GetData()->nDataLength-nCount, 0);
	return dest;
}
BString BString::Left(int nCount) const
{
	if (nCount < 0)
		nCount = 0;
	if (nCount >= GetData()->nDataLength)
		return *this;
	BString dest;
	AllocCopy(dest, nCount, 0, 0);
	return dest;
}
int BString::ReverseFind(BYTE ch) const
{
	//从最后查找
	LPTSTR lpsz = _tcsrchr(m_pchData, (_TUCHAR) ch);
	return (lpsz == NULL) ? -1 : (int)(lpsz - m_pchData);
}
int BString::Find(BYTE ch) const
{
	return Find(ch, 0);
}
int BString::Find(BYTE ch, int nStart) const
{
	int nLength = GetData()->nDataLength;
	if (nStart >= nLength)
		return -1;
	LPTSTR lpsz = _tcschr(m_pchData + nStart, (_TUCHAR)ch);
	return (lpsz == NULL) ? -1 : (int)(lpsz - m_pchData);
}
int BString::Find(LPBTSTR lpszSub) const
{
	return Find(lpszSub, 0);
}
int BString::Find(LPBTSTR lpszSub, int nStart) const
{
	assert(AfxIsValidString(lpszSub));
	int nLength = GetData()->nDataLength;
	if (nStart > nLength)
		return -1;
	LPTSTR lpsz = _tcsstr(m_pchData + nStart, lpszSub);
	return (lpsz == NULL) ? -1 : (int)(lpsz - m_pchData);
}
int BString::FindOneOf(LPBTSTR lpszCharSet) const
{
	assert(AfxIsValidString(lpszCharSet));
	LPTSTR lpsz = _tcspbrk(m_pchData, lpszCharSet);
	return (lpsz == NULL) ? -1 : (int)(lpsz - m_pchData);
}
void BString::MakeUpper()
{
	CopyBeforeWrite();
	_tcsupr(m_pchData);
}
void BString::MakeLower()
{
	CopyBeforeWrite();
	_tcslwr(m_pchData);
}
void BString::MakeReverse()
{
	CopyBeforeWrite();
	_tcsrev(m_pchData);
}
void BString::SetAt(int nIndex, BYTE ch)
{
	assert(nIndex >= 0);
	assert(nIndex < GetData()->nDataLength);
	CopyBeforeWrite();
	m_pchData[nIndex] = ch;
}
void BString::TrimRight(LPBTSTR lpszTargetList)
{
	CopyBeforeWrite();
	LPTSTR lpsz = m_pchData;
	LPTSTR lpszLast = NULL;
	while (*lpsz != '\0')
	{
		if (_tcschr(lpszTargetList, *lpsz) != NULL)
		{
			if (lpszLast == NULL)
				lpszLast = lpsz;
		}
		else
			lpszLast = NULL;
		lpsz = _tcsinc(lpsz);
	}
	if (lpszLast != NULL)
	{
		*lpszLast = '\0';
		GetData()->nDataLength = lpszLast - m_pchData;
	}
}
void BString::TrimRight(BYTE chTarget)
{
	CopyBeforeWrite();
	LPTSTR lpsz = m_pchData;
	LPTSTR lpszLast = NULL;
	while (*lpsz != '\0')
	{
		if (*lpsz == chTarget)
		{
			if (lpszLast == NULL)
				lpszLast = lpsz;
		}
		else
			lpszLast = NULL;
		lpsz = _tcsinc(lpsz);
	}
	if (lpszLast != NULL)
	{
		*lpszLast = '\0';
		GetData()->nDataLength = lpszLast - m_pchData;
	}
}
void BString::TrimRight()
{
	CopyBeforeWrite();
	LPTSTR lpsz = m_pchData;
	LPTSTR lpszLast = NULL;
	while (*lpsz != '\0')
	{
		if (_istspace(*lpsz))
		{
			if (lpszLast == NULL)
				lpszLast = lpsz;
		}
		else
			lpszLast = NULL;
		lpsz = _tcsinc(lpsz);
	}
	if (lpszLast != NULL)
	{
		// truncate at trailing space start
		*lpszLast = '\0';
		GetData()->nDataLength = lpszLast - m_pchData;
	}
}
void BString::TrimLeft(LPBTSTR lpszTargets)
{
	// if we're not trimming anything, we're not doing any work
	if (SafeStrlen(lpszTargets) == 0)
		return;
	CopyBeforeWrite();
	LPBTSTR lpsz = m_pchData;
	while (*lpsz != '\0')
	{
		if (_tcschr(lpszTargets, *lpsz) == NULL)
			break;
		lpsz = _tcsinc(lpsz);
	}
	if (lpsz != m_pchData)
	{
		// fix up data and length
		int nDataLength = GetData()->nDataLength - (lpsz - m_pchData);
		memmove(m_pchData, lpsz, (nDataLength+1)*sizeof(BYTE));
		GetData()->nDataLength = nDataLength;
	}
}
void BString::TrimLeft(BYTE chTarget)
{
	CopyBeforeWrite();
	LPBTSTR lpsz = m_pchData;
	while (chTarget == *lpsz)
		lpsz = _tcsinc(lpsz);
	if (lpsz != m_pchData)
	{
		int nDataLength = GetData()->nDataLength - (lpsz - m_pchData);
		memmove(m_pchData, lpsz, (nDataLength+1)*sizeof(BYTE));
		GetData()->nDataLength = nDataLength;
	}
}
void BString::TrimLeft()
{
	CopyBeforeWrite();
	LPBTSTR lpsz = m_pchData;
	while (_istspace(*lpsz))
		lpsz = _tcsinc(lpsz);
	if (lpsz != m_pchData)
	{
		int nDataLength = GetData()->nDataLength - (lpsz - m_pchData);
		memmove(m_pchData, lpsz, (nDataLength+1)*sizeof(BYTE));
		GetData()->nDataLength = nDataLength;
	}
}
#define TCHAR_ARG TCHAR
#define WCHAR_ARG WCHAR
#define CHAR_ARG char
struct _AFX_DOUBLE { BYTE doubleBits[sizeof(double)]; };
#ifdef _X86_
#define DOUBLE_ARG _AFX_DOUBLE
#else
#define DOUBLE_ARG double
#endif
#define FORCE_ANSI 0x10000
#define FORCE_UNICODE 0x20000
#define FORCE_INT64 0x40000
void BString::FormatV(LPBTSTR lpszFormat, va_list argList)
{
	assert(AfxIsValidString(lpszFormat));
	va_list argListSave = argList;
	// make a guess at the maximum length of the resulting string
	int nMaxLen = 0;
	for (LPBTSTR lpsz = lpszFormat; *lpsz != '\0'; lpsz = _tcsinc(lpsz))
	{
		//查找%,对%%不在查找范围
		if (*lpsz != '%' *(lpsz = _tcsinc(lpsz)) == '%')
		{
			nMaxLen += _tclen(lpsz);
			continue;
		}
		int nItemLen = 0;
		//%后面的格式判断
		int nWidth = 0;
		for (; *lpsz != '\0'; lpsz = _tcsinc(lpsz))
		{
			if (*lpsz == '#') 
				nMaxLen += 2; // 16进制 '0x'
			else if (*lpsz == '*')
				nWidth = va_arg(argList, int);
			else if (*lpsz == '-' *lpsz == '+' *lpsz == '0' 
				*lpsz == ' ')
				;
			else // hit non-flag character
				break;
		}
		// get width and skip it
		if (nWidth == 0)
		{
			// width indicated by
			nWidth = _ttoi(lpsz);
			for (; *lpsz != '\0' && _istdigit(*lpsz); lpsz = _tcsinc(lpsz))
				;
		}
		assert(nWidth >= 0);
		int nPrecision = 0;
		if (*lpsz == '.')
		{
			// skip past '.' separator (width.precision)
			lpsz = _tcsinc(lpsz);
			// get precision and skip it
			if (*lpsz == '*')
			{
				nPrecision = va_arg(argList, int);
				lpsz = _tcsinc(lpsz);
			}
			else
			{
				nPrecision = _ttoi(lpsz);
				for (; *lpsz != '\0' && _istdigit(*lpsz); lpsz = _tcsinc(lpsz))
					;
			}
			assert(nPrecision >= 0);
		}
		// should be on type modifier or specifier
		int nModifier = 0;
		if (_tcsncmp(lpsz, _T("I64"), 3) == 0)
		{
			lpsz += 3;
			nModifier = FORCE_INT64;
#if !defined(_X86_) && !defined(_ALPHA_)
			// __int64 is only available on X86 and ALPHA platforms
			ASSERT(FALSE);
#endif
		}
		else
		{
			switch (*lpsz)
			{
				// modifiers that affect size
			case 'h':
				nModifier = FORCE_ANSI;
				lpsz = _tcsinc(lpsz);
				break;
			case 'l':
				nModifier = FORCE_UNICODE;
				lpsz = _tcsinc(lpsz);
				break;
				// modifiers that do not affect size
			case 'F':
			case 'N':
			case 'L':
				lpsz = _tcsinc(lpsz);
				break;
			}
		}
		// now should be on specifier
		switch (*lpsz | nModifier)
		{
			// single characters
		case 'c':
		case 'C':
			nItemLen = 2;
			va_arg(argList, TCHAR_ARG);
			break;
		case 'c'|FORCE_ANSI:
		case 'C'|FORCE_ANSI:
			nItemLen = 2;
			va_arg(argList, CHAR_ARG);
			break;
		case 'c'|FORCE_UNICODE:
		case 'C'|FORCE_UNICODE:
			nItemLen = 2;
			va_arg(argList, WCHAR_ARG);
			break;
			// strings
		case 's':
			{
				LPBTSTR pstrNextArg = va_arg(argList, LPBTSTR);
				if (pstrNextArg == NULL)
					nItemLen = 6; // "(null)"
				else
				{
					nItemLen = lstrlen(pstrNextArg);
					nItemLen = max(1, nItemLen);
				}
			}
			break;
		case 'S':
			{
#ifndef _UNICODE
				LPWSTR pstrNextArg = va_arg(argList, LPWSTR);
				if (pstrNextArg == NULL)
					nItemLen = 6; // "(null)"
				else
				{
					nItemLen = wcslen(pstrNextArg);
					nItemLen = max(1, nItemLen);
				}
#else
				LPCSTR pstrNextArg = va_arg(argList, LPCSTR);
				if (pstrNextArg == NULL)
					nItemLen = 6; // "(null)"
				else
				{
					nItemLen = lstrlenA(pstrNextArg);
					nItemLen = max(1, nItemLen);
				}
#endif
			}
			break;
		case 's'|FORCE_ANSI:
		case 'S'|FORCE_ANSI:
			{
				LPCSTR pstrNextArg = va_arg(argList, LPCSTR);
				if (pstrNextArg == NULL)
					nItemLen = 6; // "(null)"
				else
				{
					nItemLen = lstrlenA(pstrNextArg);
					nItemLen = max(1, nItemLen);
				}
			}
			break;
		case 's'|FORCE_UNICODE:
		case 'S'|FORCE_UNICODE:
			{
				LPWSTR pstrNextArg = va_arg(argList, LPWSTR);
				if (pstrNextArg == NULL)
					nItemLen = 6; // "(null)"
				else
				{
					nItemLen = wcslen(pstrNextArg);
					nItemLen = max(1, nItemLen);
				}
			}
			break;
		}
		// adjust nItemLen for strings
		if (nItemLen != 0)
		{
			if (nPrecision != 0)
				nItemLen = min(nItemLen, nPrecision);
			nItemLen = max(nItemLen, nWidth);
		}
		else
		{
			switch (*lpsz)
			{
				// integers
			case 'd':
			case 'i':
			case 'u':
			case 'x':
			case 'X':
			case 'o':
				if (nModifier & FORCE_INT64)
					va_arg(argList, __int64);
				else
					va_arg(argList, int);
				nItemLen = 32;
				nItemLen = max(nItemLen, nWidth+nPrecision);
				break;
			case 'e':
			case 'g':
			case 'G':
				va_arg(argList, DOUBLE_ARG);
				nItemLen = 128;
				nItemLen = max(nItemLen, nWidth+nPrecision);
				break;
			case 'f':
				{
					double f;
					LPTSTR pszTemp;
					// 312 == strlen("-1+(309 zeroes).")
					// 309 zeroes == max precision of a double
					// 6 == adjustment in case precision is not specified,
					// which means that the precision defaults to 6
					pszTemp = (LPTSTR)_alloca(max(nWidth, 312+nPrecision+6));
					f = va_arg(argList, double);
					_stprintf( pszTemp, _T( "%*.*f" ), nWidth, nPrecision+6, f );
					nItemLen = _tcslen(pszTemp);
				}
				break;
			case 'p':
				va_arg(argList, void*);
				nItemLen = 32;
				nItemLen = max(nItemLen, nWidth+nPrecision);
				break;
				// no output
			case 'n':
				va_arg(argList, int*);
				break;
			default:
				assert(FALSE); // unknown formatting option
			}
		}
		// adjust nMaxLen for output nItemLen
		nMaxLen += nItemLen;
	}
	GetBuffer(nMaxLen);
	//VERIFY(_vstprintf(m_pchData, lpszFormat, argListSave) <= GetAllocLength());
	_vstprintf(m_pchData, lpszFormat, argListSave);
	ReleaseBuffer();
	va_end(argListSave);
}
void BString::Format(LPBTSTR lpszFormat, ...)
{
	assert(AfxIsValidString(lpszFormat));
	va_list argList;
	va_start(argList, lpszFormat);
	FormatV(lpszFormat, argList);
	va_end(argList);
}
void BString::ConcatCopy(int nSrc1Len, LPBTSTR lpszSrc1Data,int nSrc2Len, LPBTSTR lpszSrc2Data)
{
	int nNewLen = nSrc1Len + nSrc2Len;
	if (nNewLen != 0)
	{
		AllocBuffer(nNewLen);
		memcpy(m_pchData, lpszSrc1Data, nSrc1Len*sizeof(BYTE));
		memcpy(m_pchData+nSrc1Len, lpszSrc2Data, nSrc2Len*sizeof(BYTE));
	}
}
void BString::ConcatInPlace(int nSrcLen, LPBTSTR lpszSrcData)
{
	if (nSrcLen == 0)
		return;
	if (GetData()->nRefs > 1 GetData()->nDataLength + nSrcLen > GetData()->nAllocLength)
	{//动态分配
		BStringData* pOldData = GetData();
		ConcatCopy(GetData()->nDataLength, m_pchData, nSrcLen, lpszSrcData);
		assert(pOldData != NULL);
		BString::Release(pOldData);
	}
	else
	{//直接往后添加
		memcpy(m_pchData+GetData()->nDataLength, lpszSrcData, nSrcLen*sizeof(BYTE));
		GetData()->nDataLength += nSrcLen;
		assert(GetData()->nDataLength <= GetData()->nAllocLength);
		m_pchData[GetData()->nDataLength] = '\0';
	}
}
const BString& BString::operator+=(LPBTSTR lpsz)
{
	assert(lpsz == NULL AfxIsValidString(lpsz));
	ConcatInPlace(SafeStrlen(lpsz), lpsz);
	return *this;
}
const BString& BString::operator+=(BYTE ch)
{
	ConcatInPlace(1, &ch);
	return *this;
}
const BString& BString::operator+=(const BString& string)
{
	ConcatInPlace(string.GetData()->nDataLength, string.m_pchData);
	return *this;
}
LPTSTR BString::GetBuffer(int nMinBufLength)
{
	assert(nMinBufLength >= 0);
	if (GetData()->nRefs > 1 nMinBufLength > GetData()->nAllocLength)
	{ //重新动态分配
		BStringData* pOldData = GetData();
		int nOldLen = GetData()->nDataLength; // AllocBuffer will tromp it
		if (nMinBufLength < nOldLen)
			nMinBufLength = nOldLen;
		AllocBuffer(nMinBufLength);
		memcpy(m_pchData, pOldData->data(), (nOldLen+1)*sizeof(BYTE));
		GetData()->nDataLength = nOldLen;
		BString::Release(pOldData);
	}
	assert(GetData()->nRefs <= 1);
	assert(m_pchData != NULL);
	return m_pchData;
}
void BString::ReleaseBuffer(int nNewLength)
{
	CopyBeforeWrite(); //脱离共享数据块，
	if (nNewLength == -1)
		nNewLength = lstrlen(m_pchData); // zero terminated
	assert(nNewLength <= GetData()->nAllocLength);
	GetData()->nDataLength = nNewLength;
	m_pchData[nNewLength] = '\0';
}
LPTSTR BString::GetBufferSetLength(int nNewLength)
{
	assert(nNewLength >= 0);
	GetBuffer(nNewLength);
	GetData()->nDataLength = nNewLength;
	m_pchData[nNewLength] = '\0';
	return m_pchData;
}
void BString::FreeExtra()
{
	assert(GetData()->nDataLength <= GetData()->nAllocLength);
	if (GetData()->nDataLength != GetData()->nAllocLength)
	{
		BStringData* pOldData = GetData();
		AllocBuffer(GetData()->nDataLength);
		memcpy(m_pchData, pOldData->data(), pOldData->nDataLength*sizeof(BYTE));
		assert(m_pchData[GetData()->nDataLength] == '\0');
		BString::Release(pOldData);
	}
	assert(GetData() != NULL);
}
LPTSTR BString::LockBuffer()
{
	LPTSTR lpsz = GetBuffer(0);
	GetData()->nRefs = -1;
	return lpsz;
}
void BString::UnlockBuffer()
{
	assert(GetData()->nRefs == -1);
	if (GetData() != _afxDataNil)
		GetData()->nRefs = 1;
}
int BString::Compare(LPBTSTR lpsz) const
{
	assert(AfxIsValidString(lpsz));
	return _tcscmp(m_pchData, lpsz);
}
int BString::CompareNoCase(LPBTSTR lpsz) const
{
	assert(AfxIsValidString(lpsz));
	return _tcsicmp(m_pchData, lpsz);
} 
// BString::Collate is often slower than Compare but is MBSC/Unicode
// aware as well as locale-sensitive with respect to sort order.
int BString::Collate(LPBTSTR lpsz) const
{
	assert(AfxIsValidString(lpsz));
	return _tcscoll(m_pchData, lpsz);
} 
int BString::CollateNoCase(LPBTSTR lpsz) const
{
	assert(AfxIsValidString(lpsz));
	return _tcsicoll(m_pchData, lpsz);
} 
TCHAR BString::GetAt(int nIndex) const
{
	assert(nIndex >= 0);
	assert(nIndex < GetData()->nDataLength);
	return m_pchData[nIndex];
}
TCHAR BString::operator[](int nIndex) const
{
	assert(nIndex >= 0);
	assert(nIndex < GetData()->nDataLength);
	return m_pchData[nIndex];
}
////////////////////////////////////////////////////////////////////////////////
BString operator+(const BString& string1, const BString& string2)
{
	BString s;
	s.ConcatCopy(string1.GetData()->nDataLength, string1.m_pchData,
		string2.GetData()->nDataLength, string2.m_pchData);
	return s;
}
BString operator+(const BString& string, LPBTSTR lpsz)
{
	assert(lpsz == NULL AfxIsValidString(lpsz));
	BString s;
	s.ConcatCopy(string.GetData()->nDataLength, string.m_pchData,
		BString::SafeStrlen(lpsz), lpsz);
	return s;
}
BString operator+(LPBTSTR lpsz, const BString& string)
{
	assert(lpsz == NULL AfxIsValidString(lpsz));
	BString s;
	s.ConcatCopy(BString::SafeStrlen(lpsz), lpsz, string.GetData()->nDataLength,
		string.m_pchData);
	return s;
}
bool operator==(const BString& s1, const BString& s2)
{ return s1.Compare(s2) == 0; }
bool operator==(const BString& s1, LPBTSTR s2)
{ return s1.Compare(s2) == 0; }
bool operator==(LPBTSTR s1, const BString& s2)
{ return s2.Compare(s1) == 0; }
bool operator!=(const BString& s1, const BString& s2)
{ return s1.Compare(s2) != 0; }
bool operator!=(const BString& s1, LPBTSTR s2)
{ return s1.Compare(s2) != 0; }
bool operator!=(LPBTSTR s1, const BString& s2)
{ return s2.Compare(s1) != 0; }
bool operator<(const BString& s1, const BString& s2)
{ return s1.Compare(s2) < 0; }
bool operator<(const BString& s1, LPBTSTR s2)
{ return s1.Compare(s2) < 0; }
bool operator<(LPBTSTR s1, const BString& s2)
{ return s2.Compare(s1) > 0; }
bool operator>(const BString& s1, const BString& s2)
{ return s1.Compare(s2) > 0; }
bool operator>(const BString& s1, LPBTSTR s2)
{ return s1.Compare(s2) > 0; }
bool operator>(LPBTSTR s1, const BString& s2)
{ return s2.Compare(s1) < 0; }
bool operator<=(const BString& s1, const BString& s2)
{ return s1.Compare(s2) <= 0; }
bool operator<=(const BString& s1, LPBTSTR s2)
{ return s1.Compare(s2) <= 0; }
bool operator<=(LPBTSTR s1, const BString& s2)
{ return s2.Compare(s1) >= 0; }
bool operator>=(const BString& s1, const BString& s2)
{ return s1.Compare(s2) >= 0; }
bool operator>=(const BString& s1, LPBTSTR s2)
{ return s1.Compare(s2) >= 0; }
bool operator>=(LPBTSTR s1, const BString& s2)
{ return s2.Compare(s1) <= 0; }
////////////////////////////////////////////////////////////////////////////////
void ConstructElements(BString* pElements, int nCount)
{
	assert(nCount == 0 
		AfxIsValidAddress(pElements, nCount * sizeof(BString)));
	for (; nCount--; ++pElements)
		memcpy(pElements, &AfxGetEmptyString(), sizeof(*pElements));
}
void DestructElements(BString* pElements, int nCount)
{
	assert(nCount == 0 
		AfxIsValidAddress(pElements, nCount * sizeof(BString)));
	for (; nCount--; ++pElements)
		pElements->~BString();
}
void CopyElements(BString* pDest, const BString* pSrc, int nCount)
{
	assert(nCount == 0 
		AfxIsValidAddress(pDest, nCount * sizeof(BString)));
	assert(nCount == 0 
		AfxIsValidAddress(pSrc, nCount * sizeof(BString)));
	for (; nCount--; ++pDest, ++pSrc)
		*pDest = *pSrc;
}