MFC 字符串类CString 源代码

原文：http://blog.csdn.net/benny5609/article/details/1926088

CString使用的是引用技术,可以共享数据(这个大家都知道),另外空的CStirng是指向一个固定的地址的(_afxInitData).

另外CStirng是有长度限制的2147483647(无符号int 的最大值).

数据格式

struct CStringData

{

 long nRefs; //引用记数

 int nDataLength; //字符使用长度

 int nAllocLength; //分配长度

 TCHAR* data() { return (TCHAR*)(this+1); } //存放字符串的地方

 //this+1 相当与是CStringData[1];所以TCHAR* data()指的是CStringData[1]的地址

};

基本和网络通讯的数据包差不多

typedef struct tagAnsMarketData //统一的应答结构

{

 WORD wStkNum; //数目

 char iData[1]; //数据

}ANS_MARKET_DATA,*PANS_MARKET_DATA;

下面是代码了

#include <windows.h>

#include <assert.h>

#include <stdlib.h>

#include <malloc.h>

#include <tchar.h>

string.h

#ifndef __JONES__STRING__

#define __JONES__STRING__

struct CStringData

{

 long nRefs; //引用记数

 int nDataLength; //字符使用长度

 int nAllocLength; //分配长度

 TCHAR* data() { return (TCHAR*)(this+1); } //存放字符串的地方

 //this+1 相当与是CStringData[1];所以TCHAR* data()指的是CStringData[1]的地址

};

class CString

{

public:

 //构造函数

 CString();

 CString(const CString& stringSrc);

 CString(TCHAR ch, int nLength =1);

 CString(LPCTSTR lpsz); // CString(LPCSTR lpsz); ANSI下版本

       //CString(LPCWSTR lpsz);UNICODE下版本

 CString(LPCTSTR lpch, int nLength); //CString(LPCSTR lpch, int nLength);ANSI下版本

          //CString(LPCWSTR lpch, int nLength);//UNICODE下版本

 CString(const unsigned char* psz);

 ~CString();

 //CStringData的属性

 int GetLength() const; //得到字符长度

 int GetAllocLength() const; //得到分配的内存长度

 BOOL IsEmpty() const; //判断字符长度是否为0

 operator LPCTSTR() const; //类型转换

 void Empty(); //清空CStringData

 //操作符重载

 const CString& operator=(const CString& stringSrc);

 const CString& operator=(LPCTSTR lpsz);

 const CString& operator=(TCHAR ch);

 const CString& operator+=(const CString& string);

 const CString& operator+=(TCHAR ch);

 const CString& operator+=(LPCTSTR lpsz);

 TCHAR operator[](int nIndex) const;

friend CString operator+(const CString& string1,const CString& string2);

 friend CString operator+(const CString& string, TCHAR ch);

 friend CString operator+(TCHAR ch, const CString& string);

 friend CString operator+(const CString& string, LPCTSTR lpsz);

 friend CString operator+(LPCTSTR lpsz, const CString& string);

//操作,脱离共享数据块

 int Delete(int nIndex, int nCount = 1);//删除从nIndex开始长度为nCount的数据

 int Insert(int nIndex, TCHAR ch); //插入一个字符

 int Insert(int nIndex, LPCTSTR pstr); //插入一个字符串

 int Replace(LPCTSTR lpszOld, LPCTSTR lpszNew); //替换数据

 int Replace(TCHAR chOld, TCHAR chNew); //替换数据

 int Remove(TCHAR chRemove); //移除一个字符

 void TrimRight(LPCTSTR lpszTargetList);

 void TrimRight(TCHAR chTarget);//去掉右边chTarget

 void TrimRight(); //去掉右边空格

 void TrimLeft(LPCTSTR lpszTargets);

 void TrimLeft(TCHAR chTarget); //去掉左边chTarget

 void TrimLeft(); //去掉左边空格

 //取某段字符串

 void SetAt(int nIndex, TCHAR ch);

 TCHAR GetAt(int nIndex) const;

 CString Mid(int nFirst) const; //取某段字符串

 CString Mid(int nFirst, int nCount) const; //取某段字符串

 CString Right(int nCount) const; //取右边字符串

 CString Left(int nCount) const; //取左边字符串

 void CString::MakeUpper(); //大写

 void CString::MakeLower(); //小写

 void CString::MakeReverse(); //????不知道干什么的 strrev

 //查找

 int Find(TCHAR ch) const;

 int Find(TCHAR ch, int nStart) const;

 int ReverseFind(TCHAR ch) const;

 int Find(LPCTSTR lpszSub) const;

 int Find(LPCTSTR lpszSub, int nStart) const;

 int FindOneOf(LPCTSTR lpszCharSet) const;//得到第一个匹配lpszCharSet中其中一个字符的位置 调用_tcspbrk

 //高级操作

 LPTSTR GetBuffer(int nMinBufLength); //重新分配内存,在拷贝原来的数据

 void ReleaseBuffer(int nNewLength=-1); //在[nNewLength]='/0',对内存大小没有改变

 LPTSTR GetBufferSetLength(int nNewLength); //重新分配内存,在拷贝原来的数据

 void FreeExtra(); //深拷贝自己,然后--原来的引用记数器

 LPTSTR LockBuffer(); //引用计数器=-1,加锁

 void UnlockBuffer(); //解锁,引用计数器=1

 //比较

 int Compare(LPCTSTR lpsz) const; //区分大小写比较

 int CompareNoCase(LPCTSTR lpsz) const; //不区分大小写比较

 //比较速度没有Compare快

 int Collate(LPCTSTR lpsz) const; //区分大小写比较

 int CollateNoCase(LPCTSTR lpsz) const; //不区分大小写比较

 //格式化字符串

 void Format(LPCTSTR lpszFormat, ...);//CSting中最长的函数了,完全是自己分析的(牛啊)

private:

 void Init();

 CStringData* GetData() const; //通过m_pchData-1 得到CStringData

 void AllocBuffer(int nLen); //给CStringData分配内存,不带记数器

 void CopyBeforeWrite(); //带引用记数的复制自己深拷贝

 void AllocBeforeWrite(int nLen); //给CStringData分配内存,带记数器

 void AssignCopy(int nSrcLen, LPCTSTR lpszSrcData);//分配内存,并拷贝lpszSrcData内容

 //把nCopyIndex开始的nCopyLen长度的数据拷贝给dest,nExtraLen扩充的长度,次函数好像没下面用

 void AllocCopy(CString& dest, int nCopyLen, int nCopyIndex,int nExtraLen) const;

 void Release(); //--引用记数器并判断是否删除内存,如删除并初始化

 void FormatV(LPCTSTR lpszFormat, va_list argList);//格式化字符串

 void ConcatCopy(int nSrc1Len, LPCTSTR lpszSrc1Data,

  int nSrc2Len, LPCTSTR lpszSrc2Data);//连接数据lpszSrc1Data+lpszSrc2Data

 void ConcatInPlace(int nSrcLen, LPCTSTR lpszSrcData); //连接字符串

static void  Release(CStringData* pData); //--引用记数器并判断是否删除内存

 static void FreeData(CStringData* pData); //释放内存

 static int SafeStrlen(LPCTSTR lpsz); //得到长度

 LPTSTR m_pchData; //指向CStringData的数据区

};

/*调用CString::Compare比较大小,如果比较中有CStirng的话用

调用operator LPCTSTR()转化类型为LPCTSTR

*/

bool operator==(const CString& s1, const CString& s2);

bool operator==(const CString& s1, LPCTSTR s2);

bool operator==(LPCTSTR s1, const CString& s2);

bool operator!=(const CString& s1, const CString& s2);

bool operator!=(const CString& s1, LPCTSTR s2);

bool operator!=(LPCTSTR s1, const CString& s2);

bool operator<(const CString& s1, const CString& s2);

bool operator<(const CString& s1, LPCTSTR s2);

bool operator<(LPCTSTR s1, const CString& s2);

bool operator>(const CString& s1, const CString& s2);

bool operator>(const CString& s1, LPCTSTR s2);

bool operator>(LPCTSTR s1, const CString& s2);

bool operator<=(const CString& s1, const CString& s2);

bool operator<=(const CString& s1, LPCTSTR s2);

bool operator<=(LPCTSTR s1, const CString& s2);

bool operator>=(const CString& s1, const CString& s2);

bool operator>=(const CString& s1, LPCTSTR s2);

bool operator>=(LPCTSTR s1, const CString& s2);

//////////////////////////////////////////////////////////////////////

//检测lpsz是否有效,调用了IsBadStringPtr

BOOL AfxIsValidString(LPCTSTR lpsz, int nLength = -1);

//检测lp是否能读写权限,调用了IsBadReadPtr,IsBadStringPtr

BOOL AfxIsValidAddress(const void* lp,UINT nBytes, BOOL bReadWrite = TRUE);

//CStirng数组操作

void ConstructElements(CString* pElements, int nCount); //初始化CStirng数组

void DestructElements(CString* pElements, int nCount); //删除CStirng数组

void CopyElements(CString* pDest, const CString* pSrc, int nCount); //CString数组拷贝

#endif

string.cpp

#include "stdafx.h"

#include "string.h"

TCHAR afxChNil = '/0';

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

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

LPCTSTR _afxPchNil = (LPCTSTR)(((BYTE*)&_afxInitData)+sizeof(CStringData));

const CString&  AfxGetEmptyString()  //建立一个空的CString

{ return *(CString*)&_afxPchNil; }

BOOL AfxIsValidString(LPCTSTR lpsz, int nLength /* = -1 */)

{

 if (lpsz == NULL)

  return FALSE;

 return ::IsBadStringPtr(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 CString::Init()

{ m_pchData=AfxGetEmptyString().m_pchData; }

CString::CString()

{ Init(); }

int CString::GetLength() const

{ return GetData()->nDataLength; }

int CString::GetAllocLength() const

{ return GetData()->nAllocLength; }

BOOL CString::IsEmpty() const

{ return GetData()->nDataLength == 0; }

CStringData* CString::GetData() const

{

 assert(m_pchData != NULL);

 return ((CStringData*)m_pchData)-1;

}

CString::operator LPCTSTR() const

{ return m_pchData; }

int CString::SafeStrlen(LPCTSTR lpsz)

{ return (lpsz == NULL) ? 0 : lstrlen(lpsz); }

void CString::AllocBuffer(int nLen)

{

 assert(nLen >= 0);

 assert(nLen <= 2147483647-1);    // (signed) int 的最大值

if (nLen == 0)

  Init();

 else

 {

  CStringData* pData;

  {

   pData = (CStringData*)

    new BYTE[sizeof(CStringData) + (nLen+1)*sizeof(TCHAR)];

   pData->nAllocLength = nLen;

  }

  pData->nRefs = 1;

  pData->data()[nLen] = '/0';

  pData->nDataLength = nLen;

  m_pchData = pData->data();

 }

}

void CString::FreeData(CStringData* pData)

{

 delete[] (BYTE*)pData;

}

void CString::CopyBeforeWrite()

{

 if (GetData()->nRefs > 1)

 {

  CStringData* pData = GetData();

  Release();

  AllocBuffer(pData->nDataLength);

  memcpy(m_pchData, pData->data(), (pData->nDataLength+1)*sizeof(TCHAR));

 }

 assert(GetData()->nRefs <= 1);

}

void CString::AllocBeforeWrite(int nLen)

{

 if (GetData()->nRefs > 1 nLen > GetData()->nAllocLength)

 {

  Release();

  AllocBuffer(nLen);

 }

 assert(GetData()->nRefs <= 1);

}

void CString::AssignCopy(int nSrcLen, LPCTSTR lpszSrcData)

{

 AllocBeforeWrite(nSrcLen);

 memcpy(m_pchData, lpszSrcData, nSrcLen*sizeof(TCHAR));

 GetData()->nDataLength = nSrcLen;

 m_pchData[nSrcLen] = '/0';

}

void CString::AllocCopy(CString& 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(TCHAR));

 }

}

CString::~CString()

{

 if (GetData() != _afxDataNil)

 {

  if (InterlockedDecrement(&GetData()->nRefs) <= 0)

   FreeData(GetData());

 }

}

CString::CString(const CString& 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;

 }

}

CString::CString(LPCTSTR lpsz)

{

 Init();

 int nLen = SafeStrlen(lpsz);

 if (nLen != 0)

 {

  AllocBuffer(nLen);

  memcpy(m_pchData, lpsz, nLen*sizeof(TCHAR));

 }

}

CString::CString(LPCTSTR lpch, int nLength)

{

 Init();

 if (nLength != 0)

 {

  assert(AfxIsValidAddress(lpch, nLength, FALSE));

  AllocBuffer(nLength);

  memcpy(m_pchData, lpch, nLength*sizeof(TCHAR));

 }

}

void CString::Release()

{

 if (GetData() != _afxDataNil)

 {

  assert(GetData()->nRefs != 0);

  if (InterlockedDecrement(&GetData()->nRefs) <= 0)

   FreeData(GetData());

  Init();

 }

}

void CString::Release(CStringData* pData)

{

 if (pData != _afxDataNil)

 {

  assert(pData->nRefs != 0);

  if (InterlockedDecrement(&pData->nRefs) <= 0)

   FreeData(pData);

 }

}

void CString::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 CString& CString::operator=(const CString& 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 CString& CString::operator=(LPCTSTR lpsz)

{

 assert(lpsz == NULL AfxIsValidString(lpsz));

 AssignCopy(SafeStrlen(lpsz), lpsz);

 return *this;

}

const CString& CString::operator=(TCHAR ch)

{

 AssignCopy(1, &ch);

 return *this;

}

int CString::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(TCHAR));

  GetData()->nDataLength = nNewLength - nCount;

 }

 return nNewLength;

}

int CString::Insert(int nIndex, TCHAR 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

  CStringData* pOldData = GetData();

  LPTSTR pstr = m_pchData;

  AllocBuffer(nNewLength);

  memcpy(m_pchData, pstr, (pOldData->nDataLength+1)*sizeof(TCHAR));

  CString::Release(pOldData);

 }

 //插入数据

 memcpy(m_pchData + nIndex + 1,

  m_pchData + nIndex, (nNewLength-nIndex)*sizeof(TCHAR));

 m_pchData[nIndex] = ch;

 GetData()->nDataLength = nNewLength;

return nNewLength;

}

int CString::Insert(int nIndex, LPCTSTR 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

   CStringData* pOldData = GetData();

   LPTSTR pstr = m_pchData;

   AllocBuffer(nNewLength);

   memcpy(m_pchData, pstr, (pOldData->nDataLength+1)*sizeof(TCHAR));

   CString::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(TCHAR));

  //插入数据

  memcpy(m_pchData + nIndex,

   pstr, nInsertLength*sizeof(TCHAR));

  GetData()->nDataLength = nNewLength;

 }

return nNewLength;

}

int CString::Replace(TCHAR chOld, TCHAR chNew)

{

 int nCount = 0;

 if (chOld != chNew) //替换的不能相同

 {

  CopyBeforeWrite();

  LPTSTR psz = m_pchData;

  LPTSTR 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 CString::Replace(LPCTSTR lpszOld, LPCTSTR 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(lpszStart, 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

   CStringData* pOldData = GetData();

   LPTSTR pstr = m_pchData;

   AllocBuffer(nNewLength);

   memcpy(m_pchData, pstr, pOldData->nDataLength*sizeof(TCHAR));

   CString::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(TCHAR));

    //插入替换数据

    memcpy(lpszTarget, lpszNew, nReplacementLen*sizeof(TCHAR));

    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 CString::Remove(TCHAR 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;

}

CString CString::Mid(int nFirst) const

{

 return Mid(nFirst, GetData()->nDataLength - nFirst);

}

CString CString::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;

 

 CString dest; 

 AllocCopy(dest, nCount, nFirst, 0);

 return dest;

}

CString CString::Right(int nCount) const

{

 if (nCount < 0)

  nCount = 0;

 if (nCount >= GetData()->nDataLength)

  return *this;

CString dest;

 AllocCopy(dest, nCount, GetData()->nDataLength-nCount, 0);

 return dest;

}

CString CString::Left(int nCount) const

{

 if (nCount < 0)

  nCount = 0;

 if (nCount >= GetData()->nDataLength)

  return *this;

CString dest;

 AllocCopy(dest, nCount, 0, 0);

 return dest;

}

int CString::ReverseFind(TCHAR ch) const

{

 //从最后查找

 LPTSTR lpsz = _tcsrchr(m_pchData, (_TUCHAR) ch);

 return (lpsz == NULL) ? -1 : (int)(lpsz - m_pchData);

}

int CString::Find(TCHAR ch) const

{

 return Find(ch, 0);

}

int CString::Find(TCHAR 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 CString::Find(LPCTSTR lpszSub) const

{

 return Find(lpszSub, 0);

}

int CString::Find(LPCTSTR 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 CString::FindOneOf(LPCTSTR lpszCharSet) const

{

 assert(AfxIsValidString(lpszCharSet));

 LPTSTR lpsz = _tcspbrk(m_pchData, lpszCharSet);

 return (lpsz == NULL) ? -1 : (int)(lpsz - m_pchData);

}

void CString::MakeUpper()

{

 CopyBeforeWrite();

 _tcsupr(m_pchData);

}

void CString::MakeLower()

{

 CopyBeforeWrite();

 _tcslwr(m_pchData);

}

void CString::MakeReverse()

{

 CopyBeforeWrite();

 _tcsrev(m_pchData);

}

void CString::SetAt(int nIndex, TCHAR ch)

{

 assert(nIndex >= 0);

 assert(nIndex < GetData()->nDataLength);

CopyBeforeWrite();

 m_pchData[nIndex] = ch;

}

void CString::TrimRight(LPCTSTR 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 CString::TrimRight(TCHAR 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 CString::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 CString::TrimLeft(LPCTSTR lpszTargets)

{

 // if we're not trimming anything, we're not doing any work

 if (SafeStrlen(lpszTargets) == 0)

  return;

CopyBeforeWrite();

 LPCTSTR 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(TCHAR));

  GetData()->nDataLength = nDataLength;

 }

}

void CString::TrimLeft(TCHAR chTarget)

{

 CopyBeforeWrite();

 LPCTSTR 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(TCHAR));

  GetData()->nDataLength = nDataLength;

 }

}

void CString::TrimLeft()

{

 CopyBeforeWrite();

 LPCTSTR 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(TCHAR));

  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 CString::FormatV(LPCTSTR 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 (LPCTSTR 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':

   {

    LPCTSTR pstrNextArg = va_arg(argList, LPCTSTR);

    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 CString::Format(LPCTSTR lpszFormat, ...)

{

 assert(AfxIsValidString(lpszFormat));

va_list argList;

 va_start(argList, lpszFormat);

 FormatV(lpszFormat, argList);

 va_end(argList);

}

void CString::ConcatCopy(int nSrc1Len, LPCTSTR lpszSrc1Data,int nSrc2Len, LPCTSTR lpszSrc2Data)

{

 int nNewLen = nSrc1Len + nSrc2Len;

 if (nNewLen != 0)

 {

  AllocBuffer(nNewLen);

  memcpy(m_pchData, lpszSrc1Data, nSrc1Len*sizeof(TCHAR));

  memcpy(m_pchData+nSrc1Len, lpszSrc2Data, nSrc2Len*sizeof(TCHAR));

 }

}

void CString::ConcatInPlace(int nSrcLen, LPCTSTR lpszSrcData)

{

 if (nSrcLen == 0)

  return;

 

 if (GetData()->nRefs > 1 GetData()->nDataLength + nSrcLen > GetData()->nAllocLength)

 {//动态分配

  CStringData* pOldData = GetData();

  ConcatCopy(GetData()->nDataLength, m_pchData, nSrcLen, lpszSrcData);

  assert(pOldData != NULL);

  CString::Release(pOldData);

 }

 else

 {//直接往后添加

  memcpy(m_pchData+GetData()->nDataLength, lpszSrcData, nSrcLen*sizeof(TCHAR));

  GetData()->nDataLength += nSrcLen;

  assert(GetData()->nDataLength <= GetData()->nAllocLength);

  m_pchData[GetData()->nDataLength] = '/0';

 }

}

const CString& CString::operator+=(LPCTSTR lpsz)

{

 assert(lpsz == NULL AfxIsValidString(lpsz));

 ConcatInPlace(SafeStrlen(lpsz), lpsz);

 return *this;

}

const CString& CString::operator+=(TCHAR ch)

{

 ConcatInPlace(1, &ch);

 return *this;

}

const CString& CString::operator+=(const CString& string)

{

 ConcatInPlace(string.GetData()->nDataLength, string.m_pchData);

 return *this;

}

LPTSTR CString::GetBuffer(int nMinBufLength)

{

 assert(nMinBufLength >= 0);

 if (GetData()->nRefs > 1 nMinBufLength > GetData()->nAllocLength)

 { //重新动态分配

  CStringData* 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(TCHAR));

  GetData()->nDataLength = nOldLen;

  CString::Release(pOldData);

 }

 assert(GetData()->nRefs <= 1);

 assert(m_pchData != NULL);

 return m_pchData;

}

void CString::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 CString::GetBufferSetLength(int nNewLength)

{

 assert(nNewLength >= 0);

GetBuffer(nNewLength);

 GetData()->nDataLength = nNewLength;

 m_pchData[nNewLength] = '/0';

 return m_pchData;

}

void CString::FreeExtra()

{

 assert(GetData()->nDataLength <= GetData()->nAllocLength);

 if (GetData()->nDataLength != GetData()->nAllocLength)

 {

  CStringData* pOldData = GetData();

  AllocBuffer(GetData()->nDataLength);

  memcpy(m_pchData, pOldData->data(), pOldData->nDataLength*sizeof(TCHAR));

  assert(m_pchData[GetData()->nDataLength] == '/0');

  CString::Release(pOldData);

 }

 assert(GetData() != NULL);

}

LPTSTR CString::LockBuffer()

{

 LPTSTR lpsz = GetBuffer(0);

 GetData()->nRefs = -1;

 return lpsz;

}

void CString::UnlockBuffer()

{

 assert(GetData()->nRefs == -1);

 if (GetData() != _afxDataNil)

  GetData()->nRefs = 1;

}

int CString::Compare(LPCTSTR lpsz) const

{

 assert(AfxIsValidString(lpsz));

 return _tcscmp(m_pchData, lpsz);

}

int CString::CompareNoCase(LPCTSTR lpsz) const

{

 assert(AfxIsValidString(lpsz));

 return _tcsicmp(m_pchData, lpsz);

} 

 

// CString::Collate is often slower than Compare but is MBSC/Unicode

//  aware as well as locale-sensitive with respect to sort order.

int CString::Collate(LPCTSTR lpsz) const

{

 assert(AfxIsValidString(lpsz));

 return _tcscoll(m_pchData, lpsz);

}

int CString::CollateNoCase(LPCTSTR lpsz) const

{

 assert(AfxIsValidString(lpsz));

 return _tcsicoll(m_pchData, lpsz);

}

TCHAR CString::GetAt(int nIndex) const

{

 assert(nIndex >= 0);

 assert(nIndex < GetData()->nDataLength);

 return m_pchData[nIndex];

}

TCHAR CString::operator[](int nIndex) const

{

 assert(nIndex >= 0);

 assert(nIndex < GetData()->nDataLength);

 return m_pchData[nIndex];

}

////////////////////////////////////////////////////////////////////////////////

CString operator+(const CString& string1, const CString& string2)

{

 CString s;

 s.ConcatCopy(string1.GetData()->nDataLength, string1.m_pchData,

  string2.GetData()->nDataLength, string2.m_pchData);

 return s;

}

CString operator+(const CString& string, LPCTSTR lpsz)

{

 assert(lpsz == NULL AfxIsValidString(lpsz));

 CString s;

 s.ConcatCopy(string.GetData()->nDataLength, string.m_pchData,

  CString::SafeStrlen(lpsz), lpsz);

 return s;

}

CString operator+(LPCTSTR lpsz, const CString& string)

{

 assert(lpsz == NULL AfxIsValidString(lpsz));

 CString s;

 s.ConcatCopy(CString::SafeStrlen(lpsz), lpsz, string.GetData()->nDataLength,

  string.m_pchData);

 return s;

}

bool operator==(const CString& s1, const CString& s2)

{ return s1.Compare(s2) == 0; }

bool operator==(const CString& s1, LPCTSTR s2)

{ return s1.Compare(s2) == 0; }

bool operator==(LPCTSTR s1, const CString& s2)

{ return s2.Compare(s1) == 0; }

bool operator!=(const CString& s1, const CString& s2)

{ return s1.Compare(s2) != 0; }

bool operator!=(const CString& s1, LPCTSTR s2)

{ return s1.Compare(s2) != 0; }

bool operator!=(LPCTSTR s1, const CString& s2)

{ return s2.Compare(s1) != 0; }

bool operator<(const CString& s1, const CString& s2)

{ return s1.Compare(s2) < 0; }

bool operator<(const CString& s1, LPCTSTR s2)

{ return s1.Compare(s2) < 0; }

bool operator<(LPCTSTR s1, const CString& s2)

{ return s2.Compare(s1) > 0; }

bool operator>(const CString& s1, const CString& s2)

{ return s1.Compare(s2) > 0; }

bool operator>(const CString& s1, LPCTSTR s2)

{ return s1.Compare(s2) > 0; }

bool operator>(LPCTSTR s1, const CString& s2)

{ return s2.Compare(s1) < 0; }

bool operator<=(const CString& s1, const CString& s2)

{ return s1.Compare(s2) <= 0; }

bool operator<=(const CString& s1, LPCTSTR s2)

{ return s1.Compare(s2) <= 0; }

bool operator<=(LPCTSTR s1, const CString& s2)

{ return s2.Compare(s1) >= 0; }

bool operator>=(const CString& s1, const CString& s2)

{ return s1.Compare(s2) >= 0; }

bool operator>=(const CString& s1, LPCTSTR s2)

{ return s1.Compare(s2) >= 0; }

bool operator>=(LPCTSTR s1, const CString& s2)

{ return s2.Compare(s1) <= 0; }

////////////////////////////////////////////////////////////////////////////////

void ConstructElements(CString* pElements, int nCount)

{

 assert(nCount == 0 

  AfxIsValidAddress(pElements, nCount * sizeof(CString)));

for (; nCount--; ++pElements)

  memcpy(pElements, &AfxGetEmptyString(), sizeof(*pElements));

}

void DestructElements(CString* pElements, int nCount)

{

 assert(nCount == 0 

  AfxIsValidAddress(pElements, nCount * sizeof(CString)));

for (; nCount--; ++pElements)

  pElements->~CString();

}

void CopyElements(CString* pDest, const CString* pSrc, int nCount)

{

 assert(nCount == 0 

  AfxIsValidAddress(pDest, nCount * sizeof(CString)));

 assert(nCount == 0 

  AfxIsValidAddress(pSrc, nCount * sizeof(CString)));

for (; nCount--; ++pDest, ++pSrc)

  *pDest = *pSrc;

}