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.