how works "compare HEX"

[BlackMage2]

how works the function "compare HEX"? with me it is always grayed out

[chcg]

See

NPP_HexEdit/HexEditor/src/Hex.cpp

Lines 1460 to 1589 in baea843

 void DoCompare(void) 
 { 
 	TCHAR		szFile[MAX_PATH]; 
 	BOOL		doMatch = TRUE; 
 	tHexProp	hexProp1 = hexEdit1.GetHexProp(); 
 	tHexProp	hexProp2 = hexEdit2.GetHexProp(); 
 	tCmpResult	cmpResult = { 0 }; 
  
 	if ((hexProp1.bits != hexProp2.bits) || (hexProp1.columns != hexProp2.columns) || (hexProp1.isBin != hexProp2.isBin)) 
 	{ 
 		/* ask which hex edits should be used to have same settings in both */ 
 		CompareDlg	dlg; 
 		dlg.init((HINSTANCE)g_hModule, nppData); 
 		if (dlg.doDialog(&hexEdit1, &hexEdit2, currentSC) == IDCANCEL) { 
 			return; 
 		} 
 	} 
  
 	/* create file for compare results */ 
 	_tcscpy(cmpResult.szFileName, cmparePath); 
 	_tcscpy(szFile, ::PathFindFileName(hexEdit1.GetHexProp().szFileName)); 
 	::PathRemoveExtension(szFile); 
 	::PathAppend(cmpResult.szFileName, szFile); 
 	_tcscat(cmpResult.szFileName, _T("_")); 
 	_tcscpy(szFile, ::PathFindFileName(hexEdit2.GetHexProp().szFileName)); 
 	::PathRemoveExtension(szFile); 
 	_tcscat(cmpResult.szFileName, szFile); 
 	_tcscat(cmpResult.szFileName, _T(".cmp")); 
 	cmpResult.hFile = ::CreateFile(cmpResult.szFileName, 
 		GENERIC_READ | GENERIC_WRITE, FILE_SHARE_READ | FILE_SHARE_WRITE, 
 		NULL, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, NULL); 
  
 	if (cmpResult.hFile != INVALID_HANDLE_VALUE) 
 	{ 
 		LPSTR	buffer1 = (LPSTR)new CHAR[COMP_BLOCK + 1]; 
 		LPSTR	buffer2 = (LPSTR)new CHAR[COMP_BLOCK + 1]; 
  
 		/* get text size to comapre */ 
 		INT		maxLength1 = ScintillaMsg(nppData._scintillaMainHandle, SCI_GETTEXTLENGTH) + 1; 
 		INT		maxLength2 = ScintillaMsg(nppData._scintillaSecondHandle, SCI_GETTEXTLENGTH) + 1; 
  
 		/* get max length */ 
 		INT		curPos = 0; 
 		INT		maxLength = maxLength1; 
 		INT		minLength = maxLength1; 
 		if (maxLength2 > maxLength1) { 
 			maxLength = maxLength2; 
 		} 
 		else { 
 			minLength = maxLength2; 
 		} 
  
 		while (curPos < minLength) 
 		{ 
 			CHAR	val = FALSE; 
 			INT	    posSrc = 0; 
 			INT	    length1 = ((maxLength1 - curPos) > COMP_BLOCK ? COMP_BLOCK : (maxLength1 % COMP_BLOCK)); 
 			INT	    length2 = ((maxLength2 - curPos) > COMP_BLOCK ? COMP_BLOCK : (maxLength2 % COMP_BLOCK)); 
  
 			ScintillaGetText(nppData._scintillaMainHandle, buffer1, curPos, length1 - 1); 
 			ScintillaGetText(nppData._scintillaSecondHandle, buffer2, curPos, length2 - 1); 
  
 			while ((posSrc < length1) && (posSrc < length2)) 
 			{ 
 				DWORD	hasWritten = 0; 
  
 				if (buffer1[posSrc] != buffer2[posSrc]) 
 				{ 
 					val = TRUE; 
 					doMatch = FALSE; 
 				} 
  
 				/* increment source buffer */ 
 				posSrc++; 
  
 				/* write to file */ 
 				if (hexProp1.bits == 1) { 
 					::WriteFile(cmpResult.hFile, &val, sizeof(val), &hasWritten, NULL); 
 					val = FALSE; 
 				} 
 				else if ((posSrc % hexProp1.bits) == 0) { 
 					::WriteFile(cmpResult.hFile, &val, sizeof(val), &hasWritten, NULL); 
 					val = FALSE; 
 				} 
 			} 
  
 			/* increment file position */ 
 			curPos += posSrc; 
 		} 
  
 		if (doMatch == TRUE) 
 		{ 
 			if (NLMessageBox((HINSTANCE)g_hModule, nppData._nppHandle, _T("MsgBox CompMatch"), MB_OK) == FALSE) 
 				::MessageBox(nppData._nppHandle, _T("Files Match."), _T("Hex-Editor Compare"), MB_OK); 
 			::CloseHandle(cmpResult.hFile); 
 			::DeleteFile(cmpResult.szFileName); 
 		} 
 		else 
 		{ 
 			DWORD	hasWritten = 0; 
 			CHAR    val = TRUE; 
  
 			for (INT i = (minLength / hexProp1.bits); i < (maxLength / static_cast<INT>(hexProp1.bits)); i++) { 
 				::WriteFile(cmpResult.hFile, &val, sizeof(val), &hasWritten, NULL); 
 			} 
  
 			/* create two structures for each view */ 
 			tCmpResult* pCmpResult1 = (tCmpResult*)new tCmpResult; 
 			tCmpResult* pCmpResult2 = (tCmpResult*)new tCmpResult; 
  
 			if ((pCmpResult1 != NULL) && (pCmpResult2 != NULL)) 
 			{ 
 				/* set data */ 
 				*pCmpResult1 = cmpResult; 
 				*pCmpResult2 = cmpResult; 
  
 				hexEdit1.SetCompareResult(pCmpResult1, pCmpResult2); 
 				hexEdit2.SetCompareResult(pCmpResult2, pCmpResult1); 
 			} 
 			else 
 			{ 
 				delete pCmpResult1; 
 				delete pCmpResult2; 
 			} 
 		} 
  
 		delete[] buffer1; 
 		delete[] buffer2; 
 	} 
 } 

Two views (via context menu "Move to other view") are needed with hex mode active to have the menu command available.

But I encountered some crashes of N++ and access violations when I tried to use this option.