自学教程：C++ Empty函数代码示例

int		Panel::ProcessKey(int Key, unsigned int ControlState) {	switch (Key) {		case VK_F3:			if (ControlState == PKF_SHIFT) {				return	true;			}			break;		case VK_F4:			switch (ControlState) {				case 0:					DlgShutdown();					return true;				case PKF_SHIFT:					return	true;			}			break;		case VK_F6:			switch (ControlState) {				case 0:					if (DlgConnection()) {						psi.Control(this, FCTL_UPDATEPANEL, 0, nullptr);						psi.Control(this, FCTL_REDRAWPANEL, 0, nullptr);					}					return	true;				case PKF_SHIFT:					try {						m_conn->Open(nullptr);					} catch (WinError &e) {						farebox_code(e.code(), e.where().c_str());					}					psi.Control(this, FCTL_UPDATEPANEL, 0, nullptr);					psi.Control(this, FCTL_REDRAWPANEL, 0, nullptr);					return	true;			}			break;		case VK_F7:			switch (ControlState) {				case 0:					AutoUTF cmd = L"mstsc.exe";					if (!Empty(m_conn->host())) {						cmd += L" /v:";						cmd += m_conn->host();					}					ExecCMD(cmd);					return true;			}			break;	}	if ((ControlState == 0 && (Key == VK_F3 || Key == VK_F5 || Key == VK_F8)) ||		(ControlState == PKF_SHIFT && (Key == VK_F7 || Key == VK_F8))) {		FarPnl pInfo(this, FCTL_GETPANELINFO);		WinTS::iterator m_cur;		if (pInfo.ItemsNumber() && pInfo.CurrentItem() &&			(m_cur = std::find(m_ts.begin(), m_ts.end(), pInfo[pInfo.CurrentItem()].FindData.nFileSize)) != m_ts.end()) {			if (ControlState == 0 && Key == VK_F3) {				AutoUTF	tmp(TempFile(TempDir()));				HANDLE	hfile = ::CreateFileW(tmp.c_str(), GENERIC_WRITE, 0, nullptr, CREATE_ALWAYS, FILE_ATTRIBUTE_NORMAL, nullptr);				if (hfile != INVALID_HANDLE_VALUE) {					FileWrite(hfile, Info(m_cur));					::CloseHandle(hfile);					psi.Viewer(tmp.c_str(), nullptr, 0, 0, -1, -1,							   VF_DELETEONLYFILEONCLOSE | VF_ENABLE_F6 | VF_DISABLEHISTORY |							   VF_NONMODAL | VF_IMMEDIATERETURN, CP_AUTODETECT);				}				return	true;			} else if (ControlState == 0 && Key == VK_F5) {				DlgMessage(m_cur->id());			} else 	if (ControlState == PKF_SHIFT && Key == VK_F7) {				WinTSession::ConnectLocal(m_cur->id());			} else 	if (ControlState == 0 && Key == VK_F8) {				if (farquestion(GetMsg(txtAreYouSure), GetMsg(txtDisconnectSession)))					WinTSession::Disconnect(m_cur->id(), m_conn->host());			} else if (ControlState == PKF_SHIFT && Key == VK_F8) {				if (farquestion(GetMsg(txtAreYouSure), GetMsg(txtLogoffSession)))					WinTSession::LogOff(m_cur->id(), m_conn->host());			}			psi.Control(this, FCTL_UPDATEPANEL, 0, nullptr);			psi.Control(this, FCTL_REDRAWPANEL, 0, nullptr);			return	true;		}	}	return	false;}

bool ArenaTeam::LoadMembersFromDB(QueryResult* arenaTeamMembersResult){    if (!arenaTeamMembersResult)        return false;    bool captainPresentInTeam = false;    do    {        Field* fields = arenaTeamMembersResult->Fetch();        // prevent crash if db records are broken, when all members in result are already processed and current team hasn't got any members        if (!fields)            break;        uint32 arenaTeamId        = fields[0].GetUInt32();        if (arenaTeamId < m_TeamId)        {            // there is in table arena_team_member record which doesn't have arenateamid in arena_team table, report error            sLog.outErrorDb("ArenaTeam %u does not exist but it has record in arena_team_member table, deleting it!", arenaTeamId);            CharacterDatabase.PExecute("DELETE FROM arena_team_member WHERE arenateamid = '%u'", arenaTeamId);            continue;        }        if (arenaTeamId > m_TeamId)            // we loaded all members for this arena_team already, break cycle            break;        ArenaTeamMember newmember;        newmember.guid            = ObjectGuid(HIGHGUID_PLAYER, fields[1].GetUInt32());        newmember.games_week      = fields[2].GetUInt32();        newmember.wins_week       = fields[3].GetUInt32();        newmember.games_season    = fields[4].GetUInt32();        newmember.wins_season     = fields[5].GetUInt32();        newmember.personal_rating = fields[6].GetUInt32();        newmember.name            = fields[7].GetCppString();        newmember.Class           = fields[8].GetUInt8();        // check if member exists in characters table        if (newmember.name.empty())        {            sLog.outErrorDb("ArenaTeam %u has member with empty name - probably player %s doesn't exist, deleting him from memberlist!", arenaTeamId, newmember.guid.GetString().c_str());            DelMember(newmember.guid);            continue;        }        // arena team can't be > 2 * arenatype (2 for 2x2, 3 for 3x3, 5 for 5x5)        if (GetMembersSize() >= GetMaxMembersSize())            return false;        if (newmember.guid == GetCaptainGuid())            captainPresentInTeam = true;        m_members.push_back(newmember);    }    while (arenaTeamMembersResult->NextRow());    if (Empty() || !captainPresentInTeam)    {        // arena team is empty or captain is not in team, delete from db        sLog.outErrorDb("ArenaTeam %u does not have any members or its captain is not in team, disbanding it...", m_TeamId);        return false;    }    return true;}

//.........这里部分代码省略.........                pro = xpro;                xpro = NULL;                Clear( rx->follow );                for( i = 0; i < x->kersize; ++i ) {                    ry = &x->name.state[i]->redun[at[i]];                    if( ry->pro == pro ) {                        Union( rx->follow, ry->follow );                        ++(at[i]);                        ++ry;                    }                    if( ry->pro > xpro ) {                        xpro = ry->pro;                    }                }                UnionAnd( conflict, rx->follow, defined );                Union( defined, rx->follow );                rx->pro = pro;                ++rx;            }        xsym = NULL;        for( i = 0; i < x->kersize; ++i ) {            at[i] = 0;            if( (sym = x->name.state[i]->trans->sym) > xsym ) {                xsym = sym;            }        }        tx = trans;        while( xsym ) {            sym = xsym;            xsym = NULL;            t = s;            for( i = 0; i < x->kersize; ++i ) {                ty = &x->name.state[i]->trans[at[i]];                if( ty->sym == sym ) {                    if( !IsMarked( *ty->state ) ) {                        Mark( *ty->state );                        *t++ = ty->state;                    }                    ++(at[i]);                    ++ty;                }                if( ty->sym > xsym ) {                    xsym = ty->sym;                }            }            tx->sym = sym;            if( sym->pro ) {                ++nvtrans;            } else {                if( IsBitSet( defined, sym->id ) ) {                    SetBit( conflict, sym->id );                    while( --t >= s ) {                        Unmark( **t );                    }                    continue;                } else {                    SetBit( defined, sym->id );                }            }            tx->state = AddErrState( &errsym->enter, s, t );            ++tx;        }        x->trans = CALLOC( tx - trans + 1, a_shift_action );        memcpy( x->trans, trans, ((char *) tx) - ((char *) trans) );        if( Empty( conflict ) ) {            redun->pro = NULL;            i = 0;        } else {            i = 1;        }        while( --rx > redun ) {            AndNot( rx->follow, conflict );            if( Empty( rx->follow ) ) {                rx->pro = NULL;            } else {                ++i;            }        }        x->redun = CALLOC( i + 1, a_reduce_action );        if( i ) {            rset = CALLOC( i*wperset, a_word );            rx = redun;            while( i > 0 ) {                if( rx->pro ) {                    --i;                    x->redun[i].pro = rx->pro;                    x->redun[i].follow = rset;                    Assign( rset, rx->follow );                    rset += wperset;                }                ++rx;            }        }    }    free( trans );    free( redun );    free( conflict );    free( s );    free( at );}

HDM::HDM(){   Mnemonic = "HDM";   Empty();}

VTG::~VTG(){   Mnemonic.Empty();   Empty();}

int peek(Stack* stack){    if (Empty(stack))        return INT_MIN;    return stack->array[stack->top];}

Empty ReturnsEmpty::getEmpty(){    return Empty();}

CFX_ListCtrl::~CFX_ListCtrl() {  Empty();}

	ValueType Front(void)	{		assert(!Empty());		return Element(_context, _current);	}

void ResultIterator::CalculateBlobOrder(  GenericVector<int> *blob_indices) const {  bool context_is_ltr = current_paragraph_is_ltr_ ^ in_minor_direction_;  blob_indices->clear();  if (Empty(RIL_WORD)) return;  if (context_is_ltr || it_->word()->UnicharsInReadingOrder()) {    // Easy! just return the blobs in order;    for (int i = 0; i < word_length_; i++)      blob_indices->push_back(i);    return;  }  // The blobs are in left-to-right order, but the current reading context  // is right-to-left.  const int U_LTR = UNICHARSET::U_LEFT_TO_RIGHT;  const int U_RTL = UNICHARSET::U_RIGHT_TO_LEFT;  const int U_EURO_NUM = UNICHARSET::U_EUROPEAN_NUMBER;  const int U_EURO_NUM_SEP = UNICHARSET::U_EUROPEAN_NUMBER_SEPARATOR;  const int U_EURO_NUM_TERM = UNICHARSET::U_EUROPEAN_NUMBER_TERMINATOR;  const int U_COMMON_NUM_SEP = UNICHARSET::U_COMMON_NUMBER_SEPARATOR;  const int U_OTHER_NEUTRAL = UNICHARSET::U_OTHER_NEUTRAL;  // Step 1: Scan for and mark European Number sequences  //   [:ET:]*[:EN:]+(([:ES:]|[:CS:])?[:EN:]+)*[:ET:]*  GenericVector<int> letter_types;  for (int i = 0; i < word_length_; i++) {    letter_types.push_back(it_->word()->SymbolDirection(i));  }  // Convert a single separtor sandwiched between two EN's into an EN.  for (int i = 0; i + 2 < word_length_; i++) {    if (letter_types[i] == U_EURO_NUM && letter_types[i + 2] == U_EURO_NUM &&        (letter_types[i + 1] == U_EURO_NUM_SEP ||         letter_types[i + 1] == U_COMMON_NUM_SEP)) {      letter_types[i + 1] = U_EURO_NUM;    }  }  // Scan for sequences of European Number Terminators around ENs and convert  // them to ENs.  for (int i = 0; i < word_length_; i++) {    if (letter_types[i] == U_EURO_NUM_TERM) {      int j = i + 1;      while (j < word_length_ && letter_types[j] == U_EURO_NUM_TERM) { j++; }      if (j < word_length_ && letter_types[j] == U_EURO_NUM) {        // The sequence [i..j] should be converted to all European Numbers.        for (int k = i; k < j; k++) letter_types[k] = U_EURO_NUM;      }      j = i - 1;      while (j > -1 && letter_types[j] == U_EURO_NUM_TERM) { j--; }      if (j > -1 && letter_types[j] == U_EURO_NUM) {        // The sequence [j..i] should be converted to all European Numbers.        for (int k = j; k <= i; k++) letter_types[k] = U_EURO_NUM;      }    }  }  // Step 2: Convert all remaining types to either L or R.  // Sequences ([:L:]|[:EN:])+ (([:CS:]|[:ON:])+ ([:L:]|[:EN:])+)* -> L.  // All other are R.  for (int i = 0; i < word_length_;) {    int ti = letter_types[i];    if (ti == U_LTR || ti == U_EURO_NUM) {      // Left to right sequence; scan to the end of it.      int last_good = i;      for (int j = i + 1; j < word_length_; j++) {        int tj = letter_types[j];        if (tj == U_LTR || tj == U_EURO_NUM) {          last_good = j;        } else if (tj == U_COMMON_NUM_SEP || tj == U_OTHER_NEUTRAL) {          // do nothing.        } else {          break;        }      }      // [i..last_good] is the L sequence      for (int k = i; k <= last_good; k++) letter_types[k] = U_LTR;      i = last_good + 1;    } else {      letter_types[i] = U_RTL;      i++;    }  }  // At this point, letter_types is entirely U_LTR or U_RTL.  for (int i = word_length_ - 1; i >= 0;) {    if (letter_types[i] == U_RTL) {      blob_indices->push_back(i);      i--;    } else {      // left to right sequence.  scan to the beginning.      int j = i - 1;      for (; j >= 0 && letter_types[j] != U_RTL; j--) { }  // pass      // Now (j, i] is LTR      for (int k = j + 1; k <= i; k++) blob_indices->push_back(k);      i = j;    }  }  ASSERT_HOST(blob_indices->size() == word_length_);}

	void Next(void)	{		assert(!Empty());		++_current;	}

GraphType::~GraphType(){   Empty();}

SATELLITE_DATA::~SATELLITE_DATA(){   Empty();}

VTG::VTG(){   Mnemonic = _T("VTG");   Empty();}

bool TokenSection::IsOneToken() const{	return !Empty() && Begin->next() == End;}

int pop(Stack* stack){    if (Empty(stack))        return INT_MIN;    return stack->array[stack->top--];}

Input::Input(){	Empty();}

CVarDefMap::~CVarDefMap(){	Empty();}

CDoubleZeroString::CDoubleZeroString():	m_buf(NULL){	m_ar.SetSize(0, 16);	Empty();}

CPointerList::~CPointerList(){	Empty();}

CDoubleZeroString::~CDoubleZeroString(){	Empty();}

const Node& List::front() {	if (isEmpty()) throw Empty();	return *head;}

CUPnpNatMappingKey::CUPnpNatMappingKey(void){	Empty();}

void List::pop_front() {	if (isEmpty()) throw Empty();	Node *tmp = head->next;	delete head;	head = tmp;}

CUT_NNTPArticleList::~CUT_NNTPArticleList(){    Empty();                        // Clear article list}

PriorityQueue::~PriorityQueue(){	Empty();}