解決字串buffer overrun 的問題
解決字串buffer overrun 的問題
解決字串buffer overrun 的問題
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StrSafe Functions<br />
• 串 理 , buffer <br />
理 , buffer <strong>overrun</strong> .<br />
char* char* szString="Taiwan";<br />
int intlength=strlen(szString);<br />
(<br />
(<br />
6),<br />
6),<br />
<br />
<br />
6<br />
6<br />
char<br />
char<br />
char char errString[]={'T','a','i','w','a','n'};<br />
int interrLength=strlen(errString);<br />
strlen buffer <strong>overrun</strong> <br />
<br />
<br />
null<br />
null<br />
,<br />
,<br />
<br />
<br />
buffer<br />
buffer<br />
<strong>overrun</strong><br />
<strong>overrun</strong><br />
Microsoft StrSafe functions,<br />
理 串 見 buffer
StringCchLength 串 度<br />
StrSafe Functions<br />
#include “stdafx.h“ // <br />
#include "strsafe.h" // for String Safe functions<br />
<br />
<br />
void void CUsingUnicodeDlg::OnBnClickedOk() {<br />
char char errString[6]={'T','a','i','w','a','n'};<br />
size_t size_tiTarget; // // 串 度<br />
HRESULT hResult; hResult; // // ,<br />
}<br />
hResult=StringCchLength(errString ,, 6, 6, &iTarget);<br />
if(hResult!=S_OK) // // <br />
return return ;;<br />
<br />
<br />
數<br />
<br />
<br />
數<br />
<br />
<br />
串
見 String Safe Functions<br />
StrSafe Functions<br />
連 兩 <br />
<br />
串<br />
<br />
<br />
串<br />
<br />
<br />
串 度<br />
<br />
<br />
CRT<br />
CRT<br />
functions<br />
functions<br />
Windows<br />
Windows<br />
<br />
<br />
串 數<br />
<br />
<br />
UNICODE<br />
UNICODE<br />
<br />
<br />
ANSI<br />
ANSI<br />
WCHAR<br />
WCHAR<br />
<br />
<br />
<br />
<br />
料 <br />
<br />
String<br />
String<br />
Safe<br />
Safe<br />
<br />
<br />
串 數<br />
StringCchLength: 數 <br />
StringCbLength: byte 數 <br />
Cch Cb
UNICODE Character Set<br />
<br />
<br />
Character<br />
Character<br />
Set<br />
Set<br />
Unicode<br />
Unicode<br />
character<br />
character<br />
Set<br />
Set<br />
StrSafe Functions<br />
Step 1: General<br />
Step 2: Character Set<br />
<br />
<br />
UNICODE<br />
UNICODE<br />
_UNICODE<br />
_UNICODE<br />
link<br />
link<br />
<br />
<br />
library<br />
library<br />
#define UNICODE // for windows<br />
#define _UNICODE // for C run-time library
StringCch<br />
CchLength<br />
StringCb<br />
CbLength<br />
StrSafe Functions<br />
#include “stdafx.h“ // <br />
#include "strsafe.h" // for String Safe functions<br />
void CUsingUnicodeDlg::OnBnClickedOk() {<br />
TCHAR errString[]={L'T',L'a',L'i',L'w',L'a',L'n',0};<br />
size_t iTarget; // 串 度<br />
HRESULT hResult; // ,<br />
hResult=StringCchLength(errString,STRSAFE_MAX_CCH,&iTarget);<br />
}<br />
if(hResult!=S_OK) // <br />
return ;<br />
StringCchLength<br />
StringCchLength<br />
<br />
<br />
6<br />
6<br />
(6<br />
(6<br />
)<br />
)<br />
hResult=StringCbLength(errString,STRSAFE_MAX_CCH,&iTarget);<br />
if(hResult!=S_OK) // <br />
return ;<br />
StringCbLength<br />
StringCbLength<br />
<br />
<br />
12<br />
12<br />
(12<br />
(12<br />
bytes)<br />
bytes)
串 連 例<br />
int _tmain(int argc, _TCHAR* argv[]) {<br />
HRESULT hResult; // ,<br />
size_t MaxLength=100;<br />
TCHAR *strDestination;<br />
strDestination=new TCHAR[MaxLength]; // <br />
TCHAR *String1=_T("");<br />
TCHAR *String2=_T(" ");<br />
hResult=StringCchPrintf(strDestination, MaxLength , _T("%s") , String1);<br />
if(hResult!=S_OK) // <br />
return -1;<br />
// 連 串 例<br />
hResult=StringCchCat(strDestination,MaxLength,String2);<br />
if(hResult!=S_OK) // <br />
return -1;<br />
<br />
<br />
串 <br />
<br />
strDestination<br />
strDestination<br />
<br />
String<br />
String<br />
2<br />
2<br />
<br />
<br />
strDestination<br />
strDestination<br />
<br />
<br />
MessageBox(NULL,strDestination,_T("StringCchCat "),MB_OK);<br />
delete[] strDestination; // <br />
} 見 StringCchCatDemo 例
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