util.cpp

这是一本学习 window编程的很好的参考教材

// RawPacket.cpp : main source file for MdiTest3.exe
//
#include "stdafx.h"
#include "util.h"


/**************************************************************
*  用于在一个字符串中查找子串（ANSI）
*  char* __fastcall stristrA(const char* pszMain, const char* pszSub)
*  成功：返回字符串的起始位置指针,pszMain为源字符串，pszSub为要查找的目标
*  失败：返回NULL
*
****************************************************************/
char* __fastcall stristrA(const char* pszMain, const char* pszSub)
{
    pszMain;    // compiler thinks these are unreferenced because
    pszSub;     // they are in ecx and edx registers

    char* pszTmp1;
    char* pszTmp2;
    char  lowerch, upperch;
    if(lstrlen(pszMain)==0||lstrlen(pszSub)==0)return NULL;
// We keep the first character of pszSub in lowerch and upperch (lower and
// upper case). First we loop trying to find a match for this character. Once
// we have found a match, we start with the second character of both pszMain
// and pszSub and walk through both strings doing a CharLower on both
// characters before comparing. If we make it all the way through pszSub with
// matches, then we bail with a pointer to the string's location in pszMain.

    _asm {
		mov ecx,pszMain
		mov edx,pszSub
        mov esi, ecx    // 
        mov edi, edx    // pszSub

        // Check for NULL pointers

        test ecx, ecx
        je short NoMatch // NULL pointer for pszMain
        test edx, edx
        je short NoMatch // NULL pointer for pszSub

        sub eax, eax
        mov al, [edi]
        push eax
        call DWORD PTR CharLower
        mov lowerch, al
        push eax
        call DWORD PTR CharUpper
        mov upperch, al

        push edi    // increment the second string pointer
        call DWORD PTR CharNext
        mov  edi, eax

        mov pszTmp2, edi
        mov edi, DWORD PTR CharNext // faster to call through a register

Loop1:
        mov al, [esi]
        test al, al
        je short NoMatch        // end of main string, so no match
        cmp al, lowerch
        je short CheckString    // lowercase match?
        cmp al, upperch
        je short CheckString    // upppercase match?
        push esi
        call edi                // Call CharNext to update main string pointer
        mov esi, eax
        jmp short Loop1

CheckString:
        mov pszTmp1, esi    // save current pszMain pointer in case its a match
        push esi
        call edi            // first character of both strings match,
        mov  esi, eax       // so move to next pszMain character
        mov edi, pszTmp2
        mov al, [edi]
        jmp short Branch1

Loop3:
        push esi
        call DWORD PTR CharNext    // CharNext to change pszMain pointer
        mov  esi, eax
        push edi
        call DWORD PTR CharNext    // CharNext to change pszSub pointer
        mov  edi, eax

        mov al, [edi]
Branch1:
        test al, al
        je short Match       // zero in sub string, means we've got a match
        cmp al, [esi]
        je short Loop3

        // Doesn't match, but might be simply a case mismatch. Lower-case both
        // characters and compare again

        sub ecx, ecx
        mov cl, al  // character from pszSub
        push ecx
        call DWORD PTR CharLower
        mov cl, al
        sub eax, eax
        mov al,  [esi]   // character from pszMain
        push ecx    // preserve register
        push eax
        call DWORD PTR CharLower
        pop ecx
        cmp al, cl
        je short Loop3  // we still have a match, keep checking

        // No match, put everything back, update pszMain to the next character
        // and try again from the top

        mov esi, pszTmp1
        mov  edi, DWORD PTR CharNext
        push esi
        call edi
        mov  esi, eax
        jmp short Loop1

Match:
        mov eax, pszTmp1
        jmp short Done  // Don't just return -- always let the C portion of the code handle the return

NoMatch:
        sub eax, eax
Done:
     }

    // Note lack of return in the C portion of the code. Return value is always in
    // eax register which we have set by the time we get here
}
/**************************************************************
*  用于在一个字符串中查找子串（UNICODE）
*  char* __fastcall stristrA(const char* pszMain, const char* pszSub)
*  成功：返回字符串的起始位置指针,pszMain为源字符串，pszSub为要查找的目标
*  失败：返回NULL
*
****************************************************************/

WCHAR* __fastcall stristrW(const WCHAR* pszMain, const WCHAR* pszSub)
{
    pszMain;    // compiler thinks these are unreferenced
    pszSub;

    WCHAR* pszTmp1;
    WCHAR* pszTmp2;
    WCHAR  lowerch, upperch;
   if(lstrlenW (pszMain)==0||lstrlenW(pszSub)==0)return NULL;
// We keep the first character of pszSub in lowerch and upperch (lower and
// upper case). First we loop trying to find a match for this character. Once
// we have found a match, we start with the second character of both pszMain
// and pszSub and walk through both strings doing a CharLower on both
// characters before comparing. If we make it all the way through pszSub with
// matches, then we bail with a pointer to the strings location in pszMain.

    _asm {
		mov ecx,pszMain
		mov edx,pszSub
        mov esi, ecx    // pszMain
        mov edi, edx    // pszSub

        // Check for NULL pointers

        test ecx, ecx
        je short NoMatch // NULL pointer for pszMain
        test edx, edx
        je short NoMatch // NULL pointer for pszSub

        sub eax, eax
        mov ax, [edi]
        push eax
        call DWORD PTR CharLowerW
        mov lowerch, ax
        push eax
        call DWORD PTR CharUpperW
        mov upperch, ax

        lea edi, [edi+2]

        mov pszTmp2, edi

Loop1:
        mov ax, [esi]
        test ax, ax
        je short NoMatch        // end of main string, so no match
        cmp ax, lowerch
        je short CheckString    // lowercase match?
        cmp ax, upperch
        je short CheckString    // upppercase match?
        lea esi, [esi+2]
        jmp short Loop1

CheckString:
        mov pszTmp1, esi    // save current pszMain pointer
        lea esi, [esi+2]
        mov edi, pszTmp2
        mov ax, [edi]
        jmp short Branch1

Loop3:
        lea esi, [esi+2]
        lea edi, [edi+2]

        mov ax, [edi]
Branch1:
        test ax, ax
        je short Match       // zero in main string, means we've got a match
        cmp ax, [esi]
        je short Loop3

        // Doesn't match, but might be simply a case mismatch. Lower-case both
        // characters and compare again

        sub ecx, ecx
        mov cx, ax  // character from pszSub
        push ecx
        call DWORD PTR CharLowerW
        mov cx, ax
        sub eax, eax
        mov ax, [esi]   // character from pszMain
        push ecx        // preserve register
        push eax
        call DWORD PTR CharLowerW
        pop ecx
        cmp ax, cx
        je short Loop3  // we still have a match, keep checking

        // No match, put everything back, update pszMain to the next character
        // and try again from the top

        mov esi, pszTmp1
        lea esi, [esi+2]
        jmp short Loop1

Match:
        mov eax, pszTmp1
        jmp short Done

NoMatch:
        sub eax, eax
Done:
     }
    // Note lack of return in the C portion of the code. Return value is always in
    // eax register which we have set by the time we get here
}


BOOL IsWindowsNT()
{
	BOOL bRet = FALSE;
	BOOL bOsVersionInfoEx;
	OSVERSIONINFOEX osvi;

	// Try calling GetVersionEx using the OSVERSIONINFOEX structure,
	// If that fails, try using the OSVERSIONINFO structure.
	ZeroMemory(&osvi, sizeof(OSVERSIONINFOEX));
	osvi.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);

	if( !(bOsVersionInfoEx = GetVersionEx ((OSVERSIONINFO *) &osvi)) )
	{
		// If OSVERSIONINFOEX doesn't work, try OSVERSIONINFO.
		osvi.dwOSVersionInfoSize = sizeof (OSVERSIONINFO);
		if (! GetVersionEx ( (OSVERSIONINFO *) &osvi) ) 
			return bRet;
	}

	if (osvi.dwPlatformId & VER_PLATFORM_WIN32_NT )
	{
		bRet = TRUE;
	}

	return bRet;
}

BOOL IsWindows2k()
{
	BOOL bRet = FALSE;
	BOOL bOsVersionInfoEx;
	OSVERSIONINFOEX osvi;

	// Try calling GetVersionEx using the OSVERSIONINFOEX structure,
	// If that fails, try using the OSVERSIONINFO structure.
	ZeroMemory(&osvi, sizeof(OSVERSIONINFOEX));
	osvi.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);

	if( !(bOsVersionInfoEx = GetVersionEx ((OSVERSIONINFO *) &osvi)) )
	{
		// If OSVERSIONINFOEX doesn't work, try OSVERSIONINFO.
		osvi.dwOSVersionInfoSize = sizeof (OSVERSIONINFO);
		if (! GetVersionEx ( (OSVERSIONINFO *) &osvi) ) 
			return bRet;
	}

	if (osvi.dwPlatformId == VER_PLATFORM_WIN32_NT && osvi.dwMajorVersion >= 5)
	{
		bRet = TRUE;
	}

	return bRet;
}

//CheckSum:计算校验和的子函数 
DWORD checksum(BYTE *buffer, int size) 
{ 
	unsigned long cksum=0; 
	while(size >1) 
	{ 
		cksum+=*buffer++; 
		size -=sizeof(BYTE); 
	} 
	if(size ) 
	{ 
		cksum += *(UCHAR*)buffer; 
	} 

	cksum = (cksum >> 16) + (cksum & 0xffff); 
	cksum += (cksum >>16); 
	return (DWORD)(~cksum); 
}