Merge: Codechange: Use null pointer literal instead of the NULL macro

src/network/core/address.cpp

@@ -25,7 +25,7 @@ const char *NetworkAddress::GetHostname()
 {
 	if (StrEmpty(this->hostname) && this->address.ss_family != AF_UNSPEC) {
 		assert(this->address_length != 0);
-		getnameinfo((struct sockaddr *)&this->address, this->address_length, this->hostname, sizeof(this->hostname), NULL, 0, NI_NUMERICHOST);
+		getnameinfo((struct sockaddr *)&this->address, this->address_length, this->hostname, sizeof(this->hostname), nullptr, 0, NI_NUMERICHOST);
 	}
 	return this->hostname;
 }
@@ -131,7 +131,7 @@ const sockaddr_storage *NetworkAddress::GetAddress()
 		 * bothered to implement the specifications and allow '0' as value
 		 * that means "don't care whether it is SOCK_STREAM or SOCK_DGRAM".
 		 */
-		this->Resolve(this->address.ss_family, SOCK_STREAM, AI_ADDRCONFIG, NULL, ResolveLoopProc);
+		this->Resolve(this->address.ss_family, SOCK_STREAM, AI_ADDRCONFIG, nullptr, ResolveLoopProc);
 		this->resolved = true;
 	}
 	return &this->address;
@@ -145,7 +145,7 @@ const sockaddr_storage *NetworkAddress::GetAddress()
 bool NetworkAddress::IsFamily(int family)
 {
 	if (!this->IsResolved()) {
-		this->Resolve(family, SOCK_STREAM, AI_ADDRCONFIG, NULL, ResolveLoopProc);
+		this->Resolve(family, SOCK_STREAM, AI_ADDRCONFIG, nullptr, ResolveLoopProc);
 	}
 	return this->address.ss_family == family;
 }
@@ -167,7 +167,7 @@ bool NetworkAddress::IsInNetmask(const char *netmask)
 
 	/* Check for CIDR separator */
 	const char *chr_cidr = strchr(netmask, '/');
-	if (chr_cidr != NULL) {
+	if (chr_cidr != nullptr) {
 		int tmp_cidr = atoi(chr_cidr + 1);
 
 		/* Invalid CIDR, treat as single host */
@@ -232,7 +232,7 @@ SOCKET NetworkAddress::Resolve(int family, int socktype, int flags, SocketList *
 	seprintf(port_name, lastof(port_name), "%u", this->GetPort());
 
 	bool reset_hostname = false;
-	/* Setting both hostname to NULL and port to 0 is not allowed.
+	/* Setting both hostname to nullptr and port to 0 is not allowed.
 	 * As port 0 means bind to any port, the other must mean that
 	 * we want to bind to 'all' IPs. */
 	if (StrEmpty(this->hostname) && this->address_length == 0 && this->GetPort() == 0) {
@@ -242,7 +242,7 @@ SOCKET NetworkAddress::Resolve(int family, int socktype, int flags, SocketList *
 		strecpy(this->hostname, fam == AF_INET ? "0.0.0.0" : "::", lastof(this->hostname));
 	}
 
-	int e = getaddrinfo(StrEmpty(this->hostname) ? NULL : this->hostname, port_name, &hints, &ai);
+	int e = getaddrinfo(StrEmpty(this->hostname) ? nullptr : this->hostname, port_name, &hints, &ai);
 
 	if (reset_hostname) strecpy(this->hostname, "", lastof(this->hostname));
 
@@ -255,18 +255,18 @@ SOCKET NetworkAddress::Resolve(int family, int socktype, int flags, SocketList *
 	}
 
 	SOCKET sock = INVALID_SOCKET;
-	for (struct addrinfo *runp = ai; runp != NULL; runp = runp->ai_next) {
+	for (struct addrinfo *runp = ai; runp != nullptr; runp = runp->ai_next) {
 		/* When we are binding to multiple sockets, make sure we do not
 		 * connect to one with exactly the same address twice. That's
 		 * of course totally unneeded ;) */
-		if (sockets != NULL) {
+		if (sockets != nullptr) {
 			NetworkAddress address(runp->ai_addr, (int)runp->ai_addrlen);
 			if (sockets->Contains(address)) continue;
 		}
 		sock = func(runp);
 		if (sock == INVALID_SOCKET) continue;
 
-		if (sockets == NULL) {
+		if (sockets == nullptr) {
 			this->address_length = (int)runp->ai_addrlen;
 			assert(sizeof(this->address) >= runp->ai_addrlen);
 			memcpy(&this->address, runp->ai_addr, runp->ai_addrlen);
@@ -323,7 +323,7 @@ SOCKET NetworkAddress::Connect()
 {
 	DEBUG(net, 1, "Connecting to %s", this->GetAddressAsString());
 
-	return this->Resolve(AF_UNSPEC, SOCK_STREAM, AI_ADDRCONFIG, NULL, ConnectLoopProc);
+	return this->Resolve(AF_UNSPEC, SOCK_STREAM, AI_ADDRCONFIG, nullptr, ConnectLoopProc);
 }
 
 /**
@@ -386,9 +386,9 @@ static SOCKET ListenLoopProc(addrinfo *runp)
  */
 void NetworkAddress::Listen(int socktype, SocketList *sockets)
 {
-	assert(sockets != NULL);
+	assert(sockets != nullptr);
 
-	/* Setting both hostname to NULL and port to 0 is not allowed.
+	/* Setting both hostname to nullptr and port to 0 is not allowed.
 	 * As port 0 means bind to any port, the other must mean that
 	 * we want to bind to 'all' IPs. */
 	if (this->address_length == 0 && this->address.ss_family == AF_UNSPEC &&

src/network/core/address.h

@@ -84,7 +84,7 @@ public:
 		if (*hostname == '[') hostname++;
 		strecpy(this->hostname, StrEmpty(hostname) ? "" : hostname, lastof(this->hostname));
 		char *tmp = strrchr(this->hostname, ']');
-		if (tmp != NULL) *tmp = '\0';
+		if (tmp != nullptr) *tmp = '\0';
 
 		memset(&this->address, 0, sizeof(this->address));
 		this->address.ss_family = family;

src/network/core/host.cpp

@@ -45,7 +45,7 @@ static void NetworkFindBroadcastIPsInternal(NetworkAddressList *broadcast) // BE
 		return;
 	}
 
-	char *output_pointer = NULL;
+	char *output_pointer = nullptr;
 	int output_length = _netstat(sock, &output_pointer, 1);
 	if (output_length < 0) {
 		DEBUG(net, 0, "[core] error running _netstat");
@@ -94,9 +94,9 @@ static void NetworkFindBroadcastIPsInternal(NetworkAddressList *broadcast) // GE
 
 	if (getifaddrs(&ifap) != 0) return;
 
-	for (ifa = ifap; ifa != NULL; ifa = ifa->ifa_next) {
+	for (ifa = ifap; ifa != nullptr; ifa = ifa->ifa_next) {
 		if (!(ifa->ifa_flags & IFF_BROADCAST)) continue;
-		if (ifa->ifa_broadaddr == NULL) continue;
+		if (ifa->ifa_broadaddr == nullptr) continue;
 		if (ifa->ifa_broadaddr->sa_family != AF_INET) continue;
 
 		NetworkAddress addr(ifa->ifa_broadaddr, sizeof(sockaddr));
@@ -116,7 +116,7 @@ static void NetworkFindBroadcastIPsInternal(NetworkAddressList *broadcast) // Wi
 	INTERFACE_INFO *ifo = CallocT<INTERFACE_INFO>(num);
 
 	for (;;) {
-		if (WSAIoctl(sock, SIO_GET_INTERFACE_LIST, NULL, 0, ifo, num * sizeof(*ifo), &len, NULL, NULL) == 0) break;
+		if (WSAIoctl(sock, SIO_GET_INTERFACE_LIST, nullptr, 0, ifo, num * sizeof(*ifo), &len, nullptr, nullptr) == 0) break;
 		free(ifo);
 		if (WSAGetLastError() != WSAEFAULT) {
 			closesocket(sock);

src/network/core/packet.cpp

@@ -25,10 +25,10 @@
  */
 Packet::Packet(NetworkSocketHandler *cs)
 {
-	assert(cs != NULL);
+	assert(cs != nullptr);
 
 	this->cs     = cs;
-	this->next   = NULL;
+	this->next   = nullptr;
 	this->pos    = 0; // We start reading from here
 	this->size   = 0;
 	this->buffer = MallocT<byte>(SHRT_MAX);
@@ -54,8 +54,8 @@ Packet::~Packet()
 
 void Packet::ResetState(PacketType type)
 {
-	this->cs                   = NULL;
-	this->next                 = NULL;
+	this->cs                   = nullptr;
+	this->next                 = nullptr;
 
 	/* Skip the size so we can write that in before sending the packet */
 	this->pos                  = 0;
@@ -68,7 +68,7 @@ void Packet::ResetState(PacketType type)
  */
 void Packet::PrepareToSend()
 {
-	assert(this->cs == NULL && this->next == NULL);
+	assert(this->cs == nullptr && this->next == nullptr);
 
 	this->buffer[0] = GB(this->size, 0, 8);
 	this->buffer[1] = GB(this->size, 8, 8);
@@ -155,7 +155,7 @@ void Packet::Send_uint64(uint64 data)
  */
 void Packet::Send_string(const char *data)
 {
-	assert(data != NULL);
+	assert(data != nullptr);
 	/* The <= *is* valid due to the fact that we are comparing sizes and not the index. */
 	assert(this->size + strlen(data) + 1 <= SHRT_MAX);
 	while ((this->buffer[this->size++] = *data++) != '\0') {}
@@ -167,7 +167,7 @@ void Packet::Send_string(const char *data)
  */
 void Packet::Send_binary(const char *data, const size_t size)
 {
-	assert(data != NULL);
+	assert(data != nullptr);
 	assert(size < MAX_CMD_TEXT_LENGTH);
 	memcpy(&this->buffer[this->size], data, size);
 	this->size += (PacketSize) size;
@@ -206,7 +206,7 @@ bool Packet::CanReadFromPacket(uint bytes_to_read, bool non_fatal)
  */
 void Packet::ReadRawPacketSize()
 {
-	assert(this->cs != NULL && this->next == NULL);
+	assert(this->cs != nullptr && this->next == nullptr);
 	this->size  = (PacketSize)this->buffer[0];
 	this->size += (PacketSize)this->buffer[1] << 8;
 }

src/network/core/tcp.cpp

@@ -24,7 +24,7 @@
  */
 NetworkTCPSocketHandler::NetworkTCPSocketHandler(SOCKET s) :
 		NetworkSocketHandler(),
-		packet_queue(NULL), packet_recv(NULL),
+		packet_queue(nullptr), packet_recv(nullptr),
 		sock(s), writable(false)
 {
 }
@@ -43,13 +43,13 @@ NetworkRecvStatus NetworkTCPSocketHandler::CloseConnection(bool error)
 	NetworkSocketHandler::CloseConnection(error);
 
 	/* Free all pending and partially received packets */
-	while (this->packet_queue != NULL) {
+	while (this->packet_queue != nullptr) {
 		Packet *p = this->packet_queue->next;
 		delete this->packet_queue;
 		this->packet_queue = p;
 	}
 	delete this->packet_recv;
-	this->packet_recv = NULL;
+	this->packet_recv = nullptr;
 
 	return NETWORK_RECV_STATUS_OKAY;
 }
@@ -63,7 +63,7 @@ NetworkRecvStatus NetworkTCPSocketHandler::CloseConnection(bool error)
 void NetworkTCPSocketHandler::SendPacket(Packet *packet)
 {
 	Packet *p;
-	assert(packet != NULL);
+	assert(packet != nullptr);
 
 	packet->PrepareToSend();
 
@@ -74,12 +74,12 @@ void NetworkTCPSocketHandler::SendPacket(Packet *packet)
 
 	/* Locate last packet buffered for the client */
 	p = this->packet_queue;
-	if (p == NULL) {
+	if (p == nullptr) {
 		/* No packets yet */
 		this->packet_queue = packet;
 	} else {
 		/* Skip to the last packet */
-		while (p->next != NULL) p = p->next;
+		while (p->next != nullptr) p = p->next;
 		p->next = packet;
 	}
 }
@@ -104,7 +104,7 @@ SendPacketsState NetworkTCPSocketHandler::SendPackets(bool closing_down)
 	if (!this->IsConnected()) return SPS_CLOSED;
 
 	p = this->packet_queue;
-	while (p != NULL) {
+	while (p != nullptr) {
 		res = send(this->sock, (const char*)p->buffer + p->pos, p->size - p->pos, 0);
 		if (res == -1) {
 			int err = GET_LAST_ERROR();
@@ -142,15 +142,15 @@ SendPacketsState NetworkTCPSocketHandler::SendPackets(bool closing_down)
 
 /**
  * Receives a packet for the given client
- * @return The received packet (or NULL when it didn't receive one)
+ * @return The received packet (or nullptr when it didn't receive one)
  */
 Packet *NetworkTCPSocketHandler::ReceivePacket()
 {
 	ssize_t res;
 
-	if (!this->IsConnected()) return NULL;
+	if (!this->IsConnected()) return nullptr;
 
-	if (this->packet_recv == NULL) {
+	if (this->packet_recv == nullptr) {
 		this->packet_recv = new Packet(this);
 	}
 
@@ -167,15 +167,15 @@ Packet *NetworkTCPSocketHandler::ReceivePacket()
 					/* Something went wrong... (104 is connection reset by peer) */
 					if (err != 104) DEBUG(net, 0, "recv failed with error %d", err);
 					this->CloseConnection();
-					return NULL;
+					return nullptr;
 				}
 				/* Connection would block, so stop for now */
-				return NULL;
+				return nullptr;
 			}
 			if (res == 0) {
 				/* Client/server has left */
 				this->CloseConnection();
-				return NULL;
+				return nullptr;
 			}
 			p->pos += res;
 		}
@@ -193,22 +193,22 @@ Packet *NetworkTCPSocketHandler::ReceivePacket()
 				/* Something went wrong... (104 is connection reset by peer) */
 				if (err != 104) DEBUG(net, 0, "recv failed with error %d", err);
 				this->CloseConnection();
-				return NULL;
+				return nullptr;
 			}
 			/* Connection would block */
-			return NULL;
+			return nullptr;
 		}
 		if (res == 0) {
 			/* Client/server has left */
 			this->CloseConnection();
-			return NULL;
+			return nullptr;
 		}
 
 		p->pos += res;
 	}
 
 	/* Prepare for receiving a new packet */
-	this->packet_recv = NULL;
+	this->packet_recv = nullptr;
 
 	p->PrepareToRead();
 	return p;
@@ -231,7 +231,7 @@ bool NetworkTCPSocketHandler::CanSendReceive()
 	FD_SET(this->sock, &write_fd);
 
 	tv.tv_sec = tv.tv_usec = 0; // don't block at all.
-	if (select(FD_SETSIZE, &read_fd, &write_fd, NULL, &tv) < 0) return false;
+	if (select(FD_SETSIZE, &read_fd, &write_fd, nullptr, &tv) < 0) return false;
 
 	this->writable = !!FD_ISSET(this->sock, &write_fd);
 	return FD_ISSET(this->sock, &read_fd) != 0;

src/network/core/tcp.h

@@ -52,7 +52,7 @@ public:
 	 * Whether there is something pending in the send queue.
 	 * @return true when something is pending in the send queue.
 	 */
-	bool HasSendQueue() { return this->packet_queue != NULL; }
+	bool HasSendQueue() { return this->packet_queue != nullptr; }
 
 	NetworkTCPSocketHandler(SOCKET s = INVALID_SOCKET);
 	~NetworkTCPSocketHandler();

src/network/core/tcp_admin.cpp

@@ -115,7 +115,7 @@ NetworkRecvStatus NetworkAdminSocketHandler::HandlePacket(Packet *p)
 NetworkRecvStatus NetworkAdminSocketHandler::ReceivePackets()
 {
 	Packet *p;
-	while ((p = this->ReceivePacket()) != NULL) {
+	while ((p = this->ReceivePacket()) != nullptr) {
 		NetworkRecvStatus res = this->HandlePacket(p);
 		if (res != NETWORK_RECV_STATUS_OKAY) return res;
 	}

src/network/core/tcp_connect.cpp

@@ -33,7 +33,7 @@ TCPConnecter::TCPConnecter(const NetworkAddress &address) :
 	address(address)
 {
 	_tcp_connecters.push_back(this);
-	if (!StartNewThread(NULL, "ottd:tcp", &TCPConnecter::ThreadEntry, this)) {
+	if (!StartNewThread(nullptr, "ottd:tcp", &TCPConnecter::ThreadEntry, this)) {
 		this->Connect();
 	}
 }

src/network/core/tcp_content.cpp

@@ -47,8 +47,8 @@ void ContentInfo::TransferFrom(ContentInfo *other)
 		free(this->dependencies);
 		free(this->tags);
 		memcpy(this, other, sizeof(ContentInfo));
-		other->dependencies = NULL;
-		other->tags = NULL;
+		other->dependencies = nullptr;
+		other->tags = nullptr;
 	}
 }
 
@@ -98,11 +98,11 @@ bool ContentInfo::IsValid() const
 /**
  * Search a textfile file next to this file in the content list.
  * @param type The type of the textfile to search for.
- * @return The filename for the textfile, \c NULL otherwise.
+ * @return The filename for the textfile, \c nullptr otherwise.
  */
 const char *ContentInfo::GetTextfile(TextfileType type) const
 {
-	if (this->state == INVALID) return NULL;
+	if (this->state == INVALID) return nullptr;
 	const char *tmp;
 	switch (this->type) {
 		default: NOT_REACHED();
@@ -120,7 +120,7 @@ const char *ContentInfo::GetTextfile(TextfileType type) const
 			break;
 		case CONTENT_TYPE_NEWGRF: {
 			const GRFConfig *gc = FindGRFConfig(BSWAP32(this->unique_id), FGCM_EXACT, this->md5sum);
-			tmp = gc != NULL ? gc->filename : NULL;
+			tmp = gc != nullptr ? gc->filename : nullptr;
 			break;
 		}
 		case CONTENT_TYPE_BASE_GRAPHICS:
@@ -138,7 +138,7 @@ const char *ContentInfo::GetTextfile(TextfileType type) const
 			tmp = FindScenario(this, true);
 			break;
 	}
-	if (tmp == NULL) return NULL;
+	if (tmp == nullptr) return nullptr;
 	return ::GetTextfile(type, GetContentInfoSubDir(this->type), tmp);
 }
 #endif /* OPENTTD_MSU */
@@ -209,7 +209,7 @@ bool NetworkContentSocketHandler::ReceivePackets()
 	Packet *p;
 	static const int MAX_PACKETS_TO_RECEIVE = 42;
 	int i = MAX_PACKETS_TO_RECEIVE;
-	while (--i != 0 && (p = this->ReceivePacket()) != NULL) {
+	while (--i != 0 && (p = this->ReceivePacket()) != nullptr) {
 		bool cont = this->HandlePacket(p);
 		delete p;
 		if (!cont) return true;

src/network/core/tcp_game.cpp

@@ -26,7 +26,7 @@
  * Create a new socket for the game connection.
  * @param s The socket to connect with.
  */
-NetworkGameSocketHandler::NetworkGameSocketHandler(SOCKET s) : info(NULL), client_id(INVALID_CLIENT_ID),
+NetworkGameSocketHandler::NetworkGameSocketHandler(SOCKET s) : info(nullptr), client_id(INVALID_CLIENT_ID),
 		last_frame(_frame_counter), last_frame_server(_frame_counter), last_packet(_realtime_tick)
 {
 	this->sock = s;
@@ -134,7 +134,7 @@ NetworkRecvStatus NetworkGameSocketHandler::HandlePacket(Packet *p)
 NetworkRecvStatus NetworkGameSocketHandler::ReceivePackets()
 {
 	Packet *p;
-	while ((p = this->ReceivePacket()) != NULL) {
+	while ((p = this->ReceivePacket()) != nullptr) {
 		NetworkRecvStatus res = HandlePacket(p);
 		delete p;
 		if (res != NETWORK_RECV_STATUS_OKAY) return res;

src/network/core/tcp_game.h

@@ -131,14 +131,14 @@ struct CommandPacket;
 /** A queue of CommandPackets. */
 class CommandQueue {
 	CommandPacket *first; ///< The first packet in the queue.
-	CommandPacket *last;  ///< The last packet in the queue; only valid when first != NULL.
+	CommandPacket *last;  ///< The last packet in the queue; only valid when first != nullptr.
 	uint count;           ///< The number of items in the queue.
 
 	void Append(CommandPacket *p, bool move);
 
 public:
 	/** Initialise the command queue. */
-	CommandQueue() : first(NULL), last(NULL), count(0) {}
+	CommandQueue() : first(nullptr), last(nullptr), count(0) {}
 	/** Clear the command queue. */
 	~CommandQueue() { this->Free(); }
 	void Append(CommandPacket &p) { this->Append(&p, false); }
@@ -541,7 +541,7 @@ public:
 	 */
 	inline void SetInfo(NetworkClientInfo *info)
 	{
-		assert(info != NULL && this->info == NULL);
+		assert(info != nullptr && this->info == nullptr);
 		this->info = info;
 	}
 

src/network/core/tcp_http.cpp

@@ -43,11 +43,11 @@ NetworkHTTPSocketHandler::NetworkHTTPSocketHandler(SOCKET s,
 	redirect_depth(depth),
 	sock(s)
 {
-	size_t bufferSize = strlen(url) + strlen(host) + strlen(_openttd_revision) + (data == NULL ? 0 : strlen(data)) + 128;
+	size_t bufferSize = strlen(url) + strlen(host) + strlen(_openttd_revision) + (data == nullptr ? 0 : strlen(data)) + 128;
 	char *buffer = AllocaM(char, bufferSize);
 
 	DEBUG(net, 7, "[tcp/http] requesting %s%s", host, url);
-	if (data != NULL) {
+	if (data != nullptr) {
 		seprintf(buffer, buffer + bufferSize - 1, "POST %s HTTP/1.0\r\nHost: %s\r\nUser-Agent: OpenTTD/%s\r\nContent-Type: text/plain\r\nContent-Length: %d\r\n\r\n%s\r\n", url, host, _openttd_revision, (int)strlen(data), data);
 	} else {
 		seprintf(buffer, buffer + bufferSize - 1, "GET %s HTTP/1.0\r\nHost: %s\r\nUser-Agent: OpenTTD/%s\r\n\r\n", url, host, _openttd_revision);
@@ -108,7 +108,7 @@ static const char * const LOCATION       = "Location: ";       ///< Header for l
 int NetworkHTTPSocketHandler::HandleHeader()
 {
 	assert(strlen(HTTP_1_0) == strlen(HTTP_1_1));
-	assert(strstr(this->recv_buffer, END_OF_HEADER) != NULL);
+	assert(strstr(this->recv_buffer, END_OF_HEADER) != nullptr);
 
 	/* We expect a HTTP/1.[01] reply */
 	if (strncmp(this->recv_buffer, HTTP_1_0, strlen(HTTP_1_0)) != 0 &&
@@ -122,7 +122,7 @@ int NetworkHTTPSocketHandler::HandleHeader()
 
 		/* Get the length of the document to receive */
 		char *length = strcasestr(this->recv_buffer, CONTENT_LENGTH);
-		if (length == NULL) return_error("[tcp/http] missing 'content-length' header");
+		if (length == nullptr) return_error("[tcp/http] missing 'content-length' header");
 
 		/* Skip the header */
 		length += strlen(CONTENT_LENGTH);
@@ -163,7 +163,7 @@ int NetworkHTTPSocketHandler::HandleHeader()
 
 	/* Redirect to other URL */
 	char *uri = strcasestr(this->recv_buffer, LOCATION);
-	if (uri == NULL) return_error("[tcp/http] missing 'location' header for redirect");
+	if (uri == nullptr) return_error("[tcp/http] missing 'location' header for redirect");
 
 	uri += strlen(LOCATION);
 
@@ -178,7 +178,7 @@ int NetworkHTTPSocketHandler::HandleHeader()
 	if (ret != 0) return ret;
 
 	/* We've relinquished control of data now. */
-	this->data = NULL;
+	this->data = nullptr;
 
 	/* Restore the header. */
 	*end_of_line = '\r';
@@ -195,22 +195,22 @@ int NetworkHTTPSocketHandler::HandleHeader()
 /* static */ int NetworkHTTPSocketHandler::Connect(char *uri, HTTPCallback *callback, const char *data, int depth)
 {
 	char *hname = strstr(uri, "://");
-	if (hname == NULL) return_error("[tcp/http] invalid location");
+	if (hname == nullptr) return_error("[tcp/http] invalid location");
 
 	hname += 3;
 
 	char *url = strchr(hname, '/');
-	if (url == NULL) return_error("[tcp/http] invalid location");
+	if (url == nullptr) return_error("[tcp/http] invalid location");
 
 	*url = '\0';
 
 	/* Fetch the hostname, and possible port number. */
-	const char *company = NULL;
-	const char *port = NULL;
+	const char *company = nullptr;
+	const char *port = nullptr;
 	ParseConnectionString(&company, &port, hname);
-	if (company != NULL) return_error("[tcp/http] invalid hostname");
+	if (company != nullptr) return_error("[tcp/http] invalid hostname");
 
-	NetworkAddress address(hname, port == NULL ? 80 : atoi(port));
+	NetworkAddress address(hname, port == nullptr ? 80 : atoi(port));
 
 	/* Restore the URL. */
 	*url = '/';
@@ -246,7 +246,7 @@ int NetworkHTTPSocketHandler::Receive()
 		if (res == 0) {
 			if (this->recv_length != 0) return -1;
 
-			this->callback->OnReceiveData(NULL, 0);
+			this->callback->OnReceiveData(nullptr, 0);
 			return 0;
 		}
 
@@ -261,7 +261,7 @@ int NetworkHTTPSocketHandler::Receive()
 			char *end_of_header = strstr(this->recv_buffer, END_OF_HEADER);
 			this->recv_buffer[end] = prev;
 
-			if (end_of_header == NULL) {
+			if (end_of_header == nullptr) {
 				if (read == lengthof(this->recv_buffer)) {
 					DEBUG(net, 0, "[tcp/http] header too big");
 					return -1;
@@ -308,7 +308,7 @@ int NetworkHTTPSocketHandler::Receive()
 	}
 
 	tv.tv_sec = tv.tv_usec = 0; // don't block at all.
-	int n = select(FD_SETSIZE, &read_fd, NULL, NULL, &tv);
+	int n = select(FD_SETSIZE, &read_fd, nullptr, nullptr, &tv);
 	if (n == -1) return;
 
 	for (auto iter = _http_connections.begin(); iter < _http_connections.end(); /* nothing */) {

src/network/core/tcp_http.h

@@ -26,9 +26,9 @@ struct HTTPCallback {
 
 	/**
 	 * We're receiving data.
-	 * @param data   the received data, NULL when all data has been received.
+	 * @param data   the received data, nullptr when all data has been received.
 	 * @param length the amount of received data, 0 when all data has been received.
-	 * @note When NULL is sent the HTTP socket handler is closed/freed.
+	 * @note When nullptr is sent the HTTP socket handler is closed/freed.
 	 */
 	virtual void OnReceiveData(const char *data, size_t length) = 0;
 
@@ -68,7 +68,7 @@ public:
 	~NetworkHTTPSocketHandler();
 
 	static int Connect(char *uri, HTTPCallback *callback,
-			const char *data = NULL, int depth = 0);
+			const char *data = nullptr, int depth = 0);
 
 	static void HTTPReceive();
 };
@@ -91,7 +91,7 @@ public:
 	 */
 	NetworkHTTPContentConnecter(const NetworkAddress &address,
 			HTTPCallback *callback, const char *url,
-			const char *data = NULL, int depth = 0) :
+			const char *data = nullptr, int depth = 0) :
 		TCPConnecter(address),
 		callback(callback),
 		url(stredup(url)),
@@ -116,7 +116,7 @@ public:
 	{
 		new NetworkHTTPSocketHandler(s, this->callback, this->address.GetHostname(), this->url, this->data, this->depth);
 		/* We've relinquished control of data now. */
-		this->data = NULL;
+		this->data = nullptr;
 	}
 };
 

src/network/core/tcp_listen.h

@@ -116,7 +116,7 @@ public:
 		}
 
 		tv.tv_sec = tv.tv_usec = 0; // don't block at all.
-		if (select(FD_SETSIZE, &read_fd, &write_fd, NULL, &tv) < 0) return false;
+		if (select(FD_SETSIZE, &read_fd, &write_fd, nullptr, &tv) < 0) return false;
 
 		/* accept clients.. */
 		for (auto &s : sockets) {

src/network/core/udp.cpp

@@ -28,12 +28,12 @@ extern const uint8 _out_of_band_grf_md5[16];
  */
 NetworkUDPSocketHandler::NetworkUDPSocketHandler(NetworkAddressList *bind)
 {
-	if (bind != NULL) {
+	if (bind != nullptr) {
 		for (NetworkAddress &addr : *bind) {
 			this->bind.push_back(addr);
 		}
 	} else {
-		/* As hostname NULL and port 0/NULL don't go well when
+		/* As hostname nullptr and port 0/nullptr don't go well when
 		 * resolving it we need to add an address for each of
 		 * the address families we support. */
 		this->bind.emplace_back(nullptr, 0, AF_INET);
@@ -209,14 +209,14 @@ void NetworkUDPSocketHandler::SendNetworkGameInfo(Packet *p, const NetworkGameIn
 		uint count = 0;
 
 		/* Count number of GRFs to send information about */
-		for (c = info->grfconfig; c != NULL; c = c->next) {
+		for (c = info->grfconfig; c != nullptr; c = c->next) {
 			if (!HasBit(c->flags, GCF_STATIC)) count++;
 		}
 		p->Send_uint8(min<uint>(count, NETWORK_MAX_GRF_COUNT)); // Send number of GRFs
 
 		/* Send actual GRF Identifications */
 		uint index = 0;
-		for (c = info->grfconfig; c != NULL; c = c->next) {
+		for (c = info->grfconfig; c != nullptr; c = c->next) {
 			if (!HasBit(c->flags, GCF_STATIC)) {
 				if (index == NETWORK_MAX_GRF_COUNT - 1 && count > NETWORK_MAX_GRF_COUNT) {
 					/* Send fake GRF ID */
@@ -293,13 +293,13 @@ void NetworkUDPSocketHandler::SendNetworkGameInfoExtended(Packet *p, const Netwo
 		uint count = 0;
 
 		/* Count number of GRFs to send information about */
-		for (c = info->grfconfig; c != NULL; c = c->next) {
+		for (c = info->grfconfig; c != nullptr; c = c->next) {
 			if (!HasBit(c->flags, GCF_STATIC)) count++;
 		}
 		p->Send_uint32(count); // Send number of GRFs
 
 		/* Send actual GRF Identifications */
-		for (c = info->grfconfig; c != NULL; c = c->next) {
+		for (c = info->grfconfig; c != nullptr; c = c->next) {
 			if (!HasBit(c->flags, GCF_STATIC)) {
 				this->SendGRFIdentifier(p, &c->ident);
 			}
@@ -489,7 +489,7 @@ void NetworkUDPSocketHandler::Receive_EX_MULTI(Packet *p, NetworkAddress *client
 	if (total == 0 || index >= total) return;
 	if (!p->CanReadFromPacket(payload_size)) return;
 
-	time_t cur_time = time(NULL);
+	time_t cur_time = time(nullptr);
 
 	auto add_to_fragment = [&](FragmentSet &fs) {
 		fs.fragments[index].assign((const char *) p->buffer + p->pos, payload_size);

src/network/core/udp.h

@@ -250,7 +250,7 @@ protected:
 
 	virtual void Receive_EX_MULTI(Packet *p, NetworkAddress *client_addr);
 public:
-	NetworkUDPSocketHandler(NetworkAddressList *bind = NULL);
+	NetworkUDPSocketHandler(NetworkAddressList *bind = nullptr);
 
 	/** On destructing of this class, the socket needs to be closed */
 	virtual ~NetworkUDPSocketHandler() { this->Close(); }

src/network/network.cpp

@@ -57,7 +57,7 @@ bool _network_available;  ///< is network mode available?
 bool _network_dedicated;  ///< are we a dedicated server?
 bool _is_network_server;  ///< Does this client wants to be a network-server?
 NetworkServerGameInfo _network_game_info; ///< Information about our game.
-NetworkCompanyState *_network_company_states = NULL; ///< Statistics about some companies.
+NetworkCompanyState *_network_company_states = nullptr; ///< Statistics about some companies.
 ClientID _network_own_client_id;      ///< Our client identifier.
 ClientID _redirect_console_to_client; ///< If not invalid, redirect the console output to a client.
 bool _network_need_advertise;         ///< Whether we need to advertise.
@@ -119,7 +119,7 @@ NetworkClientInfo::~NetworkClientInfo()
 /**
  * Return the CI given it's client-identifier
  * @param client_id the ClientID to search for
- * @return return a pointer to the corresponding NetworkClientInfo struct or NULL when not found
+ * @return return a pointer to the corresponding NetworkClientInfo struct or nullptr when not found
  */
 /* static */ NetworkClientInfo *NetworkClientInfo::GetByClientID(ClientID client_id)
 {
@@ -129,13 +129,13 @@ NetworkClientInfo::~NetworkClientInfo()
 		if (ci->client_id == client_id) return ci;
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 /**
  * Return the client state given it's client-identifier
  * @param client_id the ClientID to search for
- * @return return a pointer to the corresponding NetworkClientSocket struct or NULL when not found
+ * @return return a pointer to the corresponding NetworkClientSocket struct or nullptr when not found
  */
 /* static */ ServerNetworkGameSocketHandler *ServerNetworkGameSocketHandler::GetByClientID(ClientID client_id)
 {
@@ -145,7 +145,7 @@ NetworkClientInfo::~NetworkClientInfo()
 		if (cs->client_id == client_id) return cs;
 	}
 
-	return NULL;
+	return nullptr;
 }
 
 byte NetworkSpectatorCount()
@@ -397,7 +397,7 @@ void NetworkHandlePauseChange(PauseMode prev_mode, PauseMode changed_mode)
 
 			char buffer[DRAW_STRING_BUFFER];
 			GetString(buffer, str, lastof(buffer));
-			NetworkTextMessage(NETWORK_ACTION_SERVER_MESSAGE, CC_DEFAULT, false, NULL, buffer);
+			NetworkTextMessage(NETWORK_ACTION_SERVER_MESSAGE, CC_DEFAULT, false, nullptr, buffer);
 			break;
 		}
 
@@ -560,7 +560,7 @@ void NetworkClose(bool close_admins)
 		}
 		ServerNetworkGameSocketHandler::CloseListeners();
 		ServerNetworkAdminSocketHandler::CloseListeners();
-	} else if (MyClient::my_client != NULL) {
+	} else if (MyClient::my_client != nullptr) {
 		MyClient::SendQuit();
 		MyClient::my_client->CloseConnection(NETWORK_RECV_STATUS_CONN_LOST);
 	}
@@ -573,7 +573,7 @@ void NetworkClose(bool close_admins)
 	NetworkFreeLocalCommandQueue();
 
 	free(_network_company_states);
-	_network_company_states = NULL;
+	_network_company_states = nullptr;
 
 	InitializeNetworkPools(close_admins);
 }
@@ -627,8 +627,8 @@ void NetworkTCPQueryServer(NetworkAddress address)
 void NetworkAddServer(const char *b)
 {
 	if (*b != '\0') {
-		const char *port = NULL;
-		const char *company = NULL;
+		const char *port = nullptr;
+		const char *company = nullptr;
 		char host[NETWORK_HOSTNAME_LENGTH];
 		uint16 rport;
 
@@ -638,7 +638,7 @@ void NetworkAddServer(const char *b)
 		rport = NETWORK_DEFAULT_PORT;
 
 		ParseConnectionString(&company, &port, host);
-		if (port != NULL) rport = atoi(port);
+		if (port != nullptr) rport = atoi(port);
 
 		NetworkUDPQueryServer(NetworkAddress(host, rport), true);
 	}
@@ -668,7 +668,7 @@ void NetworkRebuildHostList()
 {
 	_network_host_list.clear();
 
-	for (NetworkGameList *item = _network_game_list; item != NULL; item = item->next) {
+	for (NetworkGameList *item = _network_game_list; item != nullptr; item = item->next) {
 		if (item->manually) _network_host_list.emplace_back(item->address.GetAddressAsString(false));
 	}
 }
@@ -907,15 +907,15 @@ void NetworkGameLoop()
 		static std::unique_ptr<CommandPacket> cp;
 		static bool check_sync_state = false;
 		static uint32 sync_state[2];
-		if (f == NULL && next_date == 0) {
+		if (f == nullptr && next_date == 0) {
 			DEBUG(net, 0, "Cannot open commands.log");
 			next_date = 1;
 		}
 
-		while (f != NULL && !feof(f)) {
+		while (f != nullptr && !feof(f)) {
 			if (_date == next_date && _date_fract == next_date_fract) {
-				if (cp != NULL) {
-					NetworkSendCommand(cp->tile, cp->p1, cp->p2, cp->cmd & ~CMD_FLAGS_MASK, NULL, cp->text.c_str(), cp->company, cp->binary_length);
+				if (cp != nullptr) {
+					NetworkSendCommand(cp->tile, cp->p1, cp->p2, cp->cmd & ~CMD_FLAGS_MASK, nullptr, cp->text.c_str(), cp->company, cp->binary_length);
 					DEBUG(net, 0, "injecting: date{%08x; %02x; %02x}; %02x; %06x; %08x; %08x; %08x; \"%s\" (%x) (%s)", _date, _date_fract, _tick_skip_counter, (int)_current_company, cp->tile, cp->p1, cp->p2, cp->cmd, cp->text.c_str(), cp->binary_length, GetCommandName(cp->cmd));
 					cp.reset();
 				}
@@ -931,16 +931,16 @@ void NetworkGameLoop()
 				}
 			}
 
-			if (cp != NULL || check_sync_state) break;
+			if (cp != nullptr || check_sync_state) break;
 
 			char buff[4096];
-			if (fgets(buff, lengthof(buff), f) == NULL) break;
+			if (fgets(buff, lengthof(buff), f) == nullptr) break;
 
 			char *p = buff;
 			/* Ignore the "[date time] " part of the message */
 			if (*p == '[') {
 				p = strchr(p, ']');
-				if (p == NULL) break;
+				if (p == nullptr) break;
 				p += 2;
 			}
 
@@ -972,7 +972,7 @@ void NetworkGameLoop()
 				cp->cmd = CMD_PAUSE;
 				cp->p1 = PM_PAUSED_NORMAL;
 				cp->p2 = 1;
-				cp->callback = NULL;
+				cp->callback = nullptr;
 				cp->binary_length = 0;
 				_ddc_fastforward = false;
 			} else if (strncmp(p, "sync: ", 6) == 0) {
@@ -992,10 +992,10 @@ void NetworkGameLoop()
 				NOT_REACHED();
 			}
 		}
-		if (f != NULL && feof(f)) {
+		if (f != nullptr && feof(f)) {
 			DEBUG(net, 0, "End of commands.log");
 			fclose(f);
-			f = NULL;
+			f = nullptr;
 		}
 #endif /* DEBUG_DUMP_COMMANDS */
 		if (_frame_counter >= _frame_counter_max) {

src/network/network_admin.cpp

@@ -234,12 +234,12 @@ NetworkRecvStatus ServerNetworkAdminSocketHandler::SendClientJoin(ClientID clien
 NetworkRecvStatus ServerNetworkAdminSocketHandler::SendClientInfo(const NetworkClientSocket *cs, const NetworkClientInfo *ci)
 {
 	/* Only send data when we're a proper client, not just someone trying to query the server. */
-	if (ci == NULL) return NETWORK_RECV_STATUS_OKAY;
+	if (ci == nullptr) return NETWORK_RECV_STATUS_OKAY;
 
 	Packet *p = new Packet(ADMIN_PACKET_SERVER_CLIENT_INFO);
 
 	p->Send_uint32(ci->client_id);
-	p->Send_string(cs == NULL ? "" : const_cast<NetworkAddress &>(cs->client_address).GetHostname());
+	p->Send_string(cs == nullptr ? "" : const_cast<NetworkAddress &>(cs->client_address).GetHostname());
 	p->Send_string(ci->client_name);
 	p->Send_uint8 (ci->client_lang);
 	p->Send_uint32(ci->join_date);
@@ -734,16 +734,16 @@ NetworkRecvStatus ServerNetworkAdminSocketHandler::Receive_ADMIN_POLL(Packet *p)
 			/* The admin is requesting client info. */
 			const NetworkClientSocket *cs;
 			if (d1 == UINT32_MAX) {
-				this->SendClientInfo(NULL, NetworkClientInfo::GetByClientID(CLIENT_ID_SERVER));
+				this->SendClientInfo(nullptr, NetworkClientInfo::GetByClientID(CLIENT_ID_SERVER));
 				FOR_ALL_CLIENT_SOCKETS(cs) {
 					this->SendClientInfo(cs, cs->GetInfo());
 				}
 			} else {
 				if (d1 == CLIENT_ID_SERVER) {
-					this->SendClientInfo(NULL, NetworkClientInfo::GetByClientID(CLIENT_ID_SERVER));
+					this->SendClientInfo(nullptr, NetworkClientInfo::GetByClientID(CLIENT_ID_SERVER));
 				} else {
 					cs = NetworkClientSocket::GetByClientID((ClientID)d1);
-					if (cs != NULL) this->SendClientInfo(cs, cs->GetInfo());
+					if (cs != nullptr) this->SendClientInfo(cs, cs->GetInfo());
 				}
 			}
 			break;
@@ -757,7 +757,7 @@ NetworkRecvStatus ServerNetworkAdminSocketHandler::Receive_ADMIN_POLL(Packet *p)
 				}
 			} else {
 				company = Company::GetIfValid(d1);
-				if (company != NULL) this->SendCompanyInfo(company);
+				if (company != nullptr) this->SendCompanyInfo(company);
 			}
 			break;
 
@@ -884,7 +884,7 @@ void NetworkAdminClientError(ClientID client_id, NetworkErrorCode error_code)
  */
 void NetworkAdminCompanyInfo(const Company *company, bool new_company)
 {
-	if (company == NULL) {
+	if (company == nullptr) {
 		DEBUG(net, 1, "[admin] Empty company given for update");
 		return;
 	}
@@ -906,7 +906,7 @@ void NetworkAdminCompanyInfo(const Company *company, bool new_company)
  */
 void NetworkAdminCompanyUpdate(const Company *company)
 {
-	if (company == NULL) return;
+	if (company == nullptr) return;
 
 	ServerNetworkAdminSocketHandler *as;
 	FOR_ALL_ACTIVE_ADMIN_SOCKETS(as) {
@@ -992,7 +992,7 @@ void NetworkAdminGameScript(const char *json)
  */
 void NetworkAdminCmdLogging(const NetworkClientSocket *owner, const CommandPacket *cp)
 {
-	ClientID client_id = owner == NULL ? _network_own_client_id : owner->client_id;
+	ClientID client_id = owner == nullptr ? _network_own_client_id : owner->client_id;
 
 	ServerNetworkAdminSocketHandler *as;
 	FOR_ALL_ACTIVE_ADMIN_SOCKETS(as) {

src/network/network_chat_gui.cpp

@@ -46,7 +46,7 @@ struct ChatMessage {
 };
 
 /* used for chat window */
-static ChatMessage *_chatmsg_list = NULL; ///< The actual chat message list.
+static ChatMessage *_chatmsg_list = nullptr; ///< The actual chat message list.
 static bool _chatmessage_dirty = false;   ///< Does the chat message need repainting?
 static bool _chatmessage_visible = false; ///< Is a chat message visible.
 static bool _chat_tab_completion_active;  ///< Whether tab completion is active.
@@ -57,7 +57,7 @@ static uint MAX_CHAT_MESSAGES = 0;        ///< The limit of chat messages to sho
  * the left and pixels from the bottom. The height is the maximum height.
  */
 static PointDimension _chatmsg_box;
-static uint8 *_chatmessage_backup = NULL; ///< Backup in case text is moved.
+static uint8 *_chatmessage_backup = nullptr; ///< Backup in case text is moved.
 
 /**
  * Count the chat messages.
@@ -362,7 +362,7 @@ struct NetworkChatWindow : public Window {
 			}
 		}
 
-		return NULL;
+		return nullptr;
 	}
 
 	/**
@@ -373,7 +373,7 @@ struct NetworkChatWindow : public Window {
 	static char *ChatTabCompletionFindText(char *buf)
 	{
 		char *p = strrchr(buf, ' ');
-		if (p == NULL) return buf;
+		if (p == nullptr) return buf;
 
 		*p = '\0';
 		return p + 1;
@@ -402,7 +402,7 @@ struct NetworkChatWindow : public Window {
 		tb_buf  = ChatTabCompletionFindText(pre_buf);
 		tb_len  = strlen(tb_buf);
 
-		while ((cur_name = ChatTabCompletionNextItem(&item)) != NULL) {
+		while ((cur_name = ChatTabCompletionNextItem(&item)) != nullptr) {
 			item++;
 
 			if (_chat_tab_completion_active) {
@@ -545,7 +545,7 @@ static const NWidgetPart _nested_chat_window_widgets[] = {
 
 /** The description of the chat window. */
 static WindowDesc _chat_window_desc(
-	WDP_MANUAL, NULL, 0, 0,
+	WDP_MANUAL, nullptr, 0, 0,
 	WC_SEND_NETWORK_MSG, WC_NONE,
 	0,
 	_nested_chat_window_widgets, lengthof(_nested_chat_window_widgets)

src/network/network_client.cpp

@@ -51,7 +51,7 @@ struct PacketReader : LoadFilter {
 	size_t read_bytes;                      ///< The total number of read bytes.
 
 	/** Initialise everything. */
-	PacketReader() : LoadFilter(NULL), buf(NULL), bufe(NULL), block(NULL), written_bytes(0), read_bytes(0)
+	PacketReader() : LoadFilter(nullptr), buf(nullptr), bufe(nullptr), block(nullptr), written_bytes(0), read_bytes(0)
 	{
 	}
 
@@ -146,9 +146,9 @@ void ClientNetworkEmergencySave()
  */
 ClientNetworkGameSocketHandler::ClientNetworkGameSocketHandler (SOCKET s)
 	: NetworkGameSocketHandler (s),
-	  savegame (NULL), token (0), status (STATUS_INACTIVE)
+	  savegame (nullptr), token (0), status (STATUS_INACTIVE)
 {
-	assert(ClientNetworkGameSocketHandler::my_client == NULL);
+	assert(ClientNetworkGameSocketHandler::my_client == nullptr);
 	ClientNetworkGameSocketHandler::my_client = this;
 }
 
@@ -156,7 +156,7 @@ ClientNetworkGameSocketHandler::ClientNetworkGameSocketHandler (SOCKET s)
 ClientNetworkGameSocketHandler::~ClientNetworkGameSocketHandler()
 {
 	assert(ClientNetworkGameSocketHandler::my_client == this);
-	ClientNetworkGameSocketHandler::my_client = NULL;
+	ClientNetworkGameSocketHandler::my_client = nullptr;
 
 	delete this->savegame;
 }
@@ -307,7 +307,7 @@ void ClientNetworkGameSocketHandler::ClientError(NetworkRecvStatus res)
 
 
 /** Our client's connection. */
-ClientNetworkGameSocketHandler * ClientNetworkGameSocketHandler::my_client = NULL;
+ClientNetworkGameSocketHandler * ClientNetworkGameSocketHandler::my_client = nullptr;
 
 /** Last frame we performed an ack. */
 static uint32 last_ack_frame;
@@ -326,9 +326,9 @@ static uint8 _network_server_max_spectators;
 CompanyID _network_join_as;
 
 /** Login password from -p argument */
-const char *_network_join_server_password = NULL;
+const char *_network_join_server_password = nullptr;
 /** Company password from -P argument */
-const char *_network_join_company_password = NULL;
+const char *_network_join_company_password = nullptr;
 
 /** Make sure the server ID length is the same as a md5 hash. */
 assert_compile(NETWORK_SERVER_ID_LENGTH == 16 * 2 + 1);
@@ -539,7 +539,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::SendMove(CompanyID company, co
  */
 bool ClientNetworkGameSocketHandler::IsConnected()
 {
-	return my_client != NULL && my_client->status == STATUS_ACTIVE;
+	return my_client != nullptr && my_client->status == STATUS_ACTIVE;
 }
 
 
@@ -548,7 +548,7 @@ bool ClientNetworkGameSocketHandler::IsConnected()
  *   DEF_CLIENT_RECEIVE_COMMAND has parameter: Packet *p
  ************/
 
-extern bool SafeLoad(const char *filename, SaveLoadOperation fop, DetailedFileType dft, GameMode newgm, Subdirectory subdir, struct LoadFilter *lf = NULL);
+extern bool SafeLoad(const char *filename, SaveLoadOperation fop, DetailedFileType dft, GameMode newgm, Subdirectory subdir, struct LoadFilter *lf = nullptr);
 
 NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_FULL(Packet *p)
 {
@@ -582,7 +582,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_COMPANY_INFO(Pa
 		if (current >= MAX_COMPANIES) return NETWORK_RECV_STATUS_CLOSE_QUERY;
 
 		NetworkCompanyInfo *company_info = GetLobbyCompanyInfo(current);
-		if (company_info == NULL) return NETWORK_RECV_STATUS_CLOSE_QUERY;
+		if (company_info == nullptr) return NETWORK_RECV_STATUS_CLOSE_QUERY;
 
 		p->Recv_string(company_info->company_name, sizeof(company_info->company_name));
 		company_info->inaugurated_year = p->Recv_uint32();
@@ -625,7 +625,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_CLIENT_INFO(Pac
 	if (this->HasClientQuit()) return NETWORK_RECV_STATUS_CONN_LOST;
 
 	ci = NetworkClientInfo::GetByClientID(client_id);
-	if (ci != NULL) {
+	if (ci != nullptr) {
 		if (playas == ci->client_playas && strcmp(name, ci->client_name) != 0) {
 			/* Client name changed, display the change */
 			NetworkTextMessage(NETWORK_ACTION_NAME_CHANGE, CC_DEFAULT, false, ci->client_name, name);
@@ -721,7 +721,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_CHECK_NEWGRFS(P
 
 		/* Check whether we know this GRF */
 		const GRFConfig *f = FindGRFConfig(c.grfid, FGCM_EXACT, c.md5sum);
-		if (f == NULL) {
+		if (f == nullptr) {
 			/* We do not know this GRF, bail out of initialization */
 			char buf[sizeof(c.md5sum) * 2 + 1];
 			md5sumToString(buf, lastof(buf), c.md5sum);
@@ -807,7 +807,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_MAP_BEGIN(Packe
 	if (this->status < STATUS_AUTHORIZED || this->status >= STATUS_MAP) return NETWORK_RECV_STATUS_MALFORMED_PACKET;
 	this->status = STATUS_MAP;
 
-	if (this->savegame != NULL) return NETWORK_RECV_STATUS_MALFORMED_PACKET;
+	if (this->savegame != nullptr) return NETWORK_RECV_STATUS_MALFORMED_PACKET;
 
 	this->savegame = new PacketReader();
 
@@ -825,7 +825,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_MAP_BEGIN(Packe
 NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_MAP_SIZE(Packet *p)
 {
 	if (this->status != STATUS_MAP) return NETWORK_RECV_STATUS_MALFORMED_PACKET;
-	if (this->savegame == NULL) return NETWORK_RECV_STATUS_MALFORMED_PACKET;
+	if (this->savegame == nullptr) return NETWORK_RECV_STATUS_MALFORMED_PACKET;
 
 	_network_join_bytes_total = p->Recv_uint32();
 	SetWindowDirty(WC_NETWORK_STATUS_WINDOW, WN_NETWORK_STATUS_WINDOW_JOIN);
@@ -836,7 +836,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_MAP_SIZE(Packet
 NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_MAP_DATA(Packet *p)
 {
 	if (this->status != STATUS_MAP) return NETWORK_RECV_STATUS_MALFORMED_PACKET;
-	if (this->savegame == NULL) return NETWORK_RECV_STATUS_MALFORMED_PACKET;
+	if (this->savegame == nullptr) return NETWORK_RECV_STATUS_MALFORMED_PACKET;
 
 	/* We are still receiving data, put it to the file */
 	this->savegame->AddPacket(p);
@@ -850,7 +850,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_MAP_DATA(Packet
 NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_MAP_DONE(Packet *p)
 {
 	if (this->status != STATUS_MAP) return NETWORK_RECV_STATUS_MALFORMED_PACKET;
-	if (this->savegame == NULL) return NETWORK_RECV_STATUS_MALFORMED_PACKET;
+	if (this->savegame == nullptr) return NETWORK_RECV_STATUS_MALFORMED_PACKET;
 
 	_network_join_status = NETWORK_JOIN_STATUS_PROCESSING;
 	SetWindowDirty(WC_NETWORK_STATUS_WINDOW, WN_NETWORK_STATUS_WINDOW_JOIN);
@@ -863,12 +863,12 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_MAP_DONE(Packet
 	 * game, which would cause us to free this->savegame twice.
 	 */
 	LoadFilter *lf = this->savegame;
-	this->savegame = NULL;
+	this->savegame = nullptr;
 	lf->Reset();
 
 	/* The map is done downloading, load it */
 	ClearErrorMessages();
-	bool load_success = SafeLoad(NULL, SLO_LOAD, DFT_GAME_FILE, GM_NORMAL, NO_DIRECTORY, lf);
+	bool load_success = SafeLoad(nullptr, SLO_LOAD, DFT_GAME_FILE, GM_NORMAL, NO_DIRECTORY, lf);
 
 	/* Long savegame loads shouldn't affect the lag calculation! */
 	this->last_packet = _realtime_tick;
@@ -894,7 +894,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_MAP_DONE(Packet
 			 * the server will give us a client-id and let us in */
 			_network_join_status = NETWORK_JOIN_STATUS_REGISTERING;
 			ShowJoinStatusWindow();
-			NetworkSendCommand(0, CCA_NEW, 0, CMD_COMPANY_CTRL, NULL, NULL, _local_company, 0);
+			NetworkSendCommand(0, CCA_NEW, 0, CMD_COMPANY_CTRL, nullptr, nullptr, _local_company, 0);
 		}
 	} else {
 		/* take control over an existing company */
@@ -959,7 +959,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_COMMAND(Packet
 	cp.frame    = p->Recv_uint32();
 	cp.my_cmd   = p->Recv_bool();
 
-	if (err != NULL) {
+	if (err != nullptr) {
 		IConsolePrintF(CC_ERROR, "WARNING: %s from server, dropping...", err);
 		return NETWORK_RECV_STATUS_MALFORMED_PACKET;
 	}
@@ -974,7 +974,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_CHAT(Packet *p)
 	if (this->status != STATUS_ACTIVE) return NETWORK_RECV_STATUS_MALFORMED_PACKET;
 
 	char name[NETWORK_NAME_LENGTH], msg[NETWORK_CHAT_LENGTH];
-	const NetworkClientInfo *ci = NULL, *ci_to;
+	const NetworkClientInfo *ci = nullptr, *ci_to;
 
 	NetworkAction action = (NetworkAction)p->Recv_uint8();
 	ClientID client_id = (ClientID)p->Recv_uint32();
@@ -984,7 +984,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_CHAT(Packet *p)
 	data.recv(p);
 
 	ci_to = NetworkClientInfo::GetByClientID(client_id);
-	if (ci_to == NULL) return NETWORK_RECV_STATUS_OKAY;
+	if (ci_to == nullptr) return NETWORK_RECV_STATUS_OKAY;
 
 	/* Did we initiate the action locally? */
 	if (self_send) {
@@ -1017,7 +1017,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_CHAT(Packet *p)
 		ci = ci_to;
 	}
 
-	if (ci != NULL) {
+	if (ci != nullptr) {
 		NetworkTextMessage(action, GetDrawStringCompanyColour(ci->client_playas), self_send, name, msg, data);
 	}
 	return NETWORK_RECV_STATUS_OKAY;
@@ -1030,8 +1030,8 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_ERROR_QUIT(Pack
 	ClientID client_id = (ClientID)p->Recv_uint32();
 
 	NetworkClientInfo *ci = NetworkClientInfo::GetByClientID(client_id);
-	if (ci != NULL) {
-		NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, ci->client_name, NULL, GetNetworkErrorMsg((NetworkErrorCode)p->Recv_uint8()));
+	if (ci != nullptr) {
+		NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, ci->client_name, nullptr, GetNetworkErrorMsg((NetworkErrorCode)p->Recv_uint8()));
 		delete ci;
 	}
 
@@ -1047,8 +1047,8 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_QUIT(Packet *p)
 	ClientID client_id = (ClientID)p->Recv_uint32();
 
 	NetworkClientInfo *ci = NetworkClientInfo::GetByClientID(client_id);
-	if (ci != NULL) {
-		NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, ci->client_name, NULL, STR_NETWORK_MESSAGE_CLIENT_LEAVING);
+	if (ci != nullptr) {
+		NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, ci->client_name, nullptr, STR_NETWORK_MESSAGE_CLIENT_LEAVING);
 		delete ci;
 	} else {
 		DEBUG(net, 0, "Unknown client (%d) is leaving the game", client_id);
@@ -1067,7 +1067,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_JOIN(Packet *p)
 	ClientID client_id = (ClientID)p->Recv_uint32();
 
 	NetworkClientInfo *ci = NetworkClientInfo::GetByClientID(client_id);
-	if (ci != NULL) {
+	if (ci != nullptr) {
 		NetworkTextMessage(NETWORK_ACTION_JOIN, CC_DEFAULT, false, ci->client_name);
 	}
 
@@ -1137,7 +1137,7 @@ NetworkRecvStatus ClientNetworkGameSocketHandler::Receive_SERVER_MOVE(Packet *p)
 
 	const NetworkClientInfo *ci = NetworkClientInfo::GetByClientID(client_id);
 	/* Just make sure we do not try to use a client_index that does not exist */
-	if (ci == NULL) return NETWORK_RECV_STATUS_OKAY;
+	if (ci == nullptr) return NETWORK_RECV_STATUS_OKAY;
 
 	/* if not valid player, force spectator, else check player exists */
 	if (!Company::IsValidID(company_id)) company_id = COMPANY_SPECTATOR;
@@ -1261,7 +1261,7 @@ void NetworkUpdateClientName()
 {
 	NetworkClientInfo *ci = NetworkClientInfo::GetByClientID(_network_own_client_id);
 
-	if (ci == NULL) return;
+	if (ci == nullptr) return;
 
 	/* Don't change the name if it is the same as the old name */
 	if (strcmp(ci->client_name, _settings_client.network.client_name) != 0) {

src/network/network_command.cpp

@@ -21,7 +21,7 @@
 
 /** Table with all the callbacks we'll use for conversion*/
 static CommandCallback * const _callback_table[] = {
-	/* 0x00 */ NULL,
+	/* 0x00 */ nullptr,
 	/* 0x01 */ CcBuildPrimaryVehicle,
 	/* 0x02 */ CcBuildAirport,
 	/* 0x03 */ CcBuildBridge,
@@ -69,8 +69,8 @@ void CommandQueue::Append(CommandPacket *p, bool move)
 	} else {
 		*add = *p;
 	}
-	add->next = NULL;
-	if (this->first == NULL) {
+	add->next = nullptr;
+	if (this->first == nullptr) {
 		this->first = add;
 	} else {
 		this->last->next = add;
@@ -89,15 +89,15 @@ std::unique_ptr<CommandPacket> CommandQueue::Pop(bool ignore_paused)
 
 	CommandPacket **prev = &this->first;
 	CommandPacket *ret = this->first;
-	CommandPacket *prev_item = NULL;
+	CommandPacket *prev_item = nullptr;
 	if (ignore_paused && _pause_mode != PM_UNPAUSED) {
-		while (ret != NULL && !IsCommandAllowedWhilePaused(ret->cmd)) {
+		while (ret != nullptr && !IsCommandAllowedWhilePaused(ret->cmd)) {
 			prev_item = ret;
 			prev = &ret->next;
 			ret = ret->next;
 		}
 	}
-	if (ret != NULL) {
+	if (ret != nullptr) {
 		if (ret == this->last) this->last = prev_item;
 		*prev = ret->next;
 		this->count--;
@@ -114,17 +114,17 @@ CommandPacket *CommandQueue::Peek(bool ignore_paused)
 {
 	if (!ignore_paused || _pause_mode == PM_UNPAUSED) return this->first;
 
-	for (CommandPacket *p = this->first; p != NULL; p = p->next) {
+	for (CommandPacket *p = this->first; p != nullptr; p = p->next) {
 		if (IsCommandAllowedWhilePaused(p->cmd)) return p;
 	}
-	return NULL;
+	return nullptr;
 }
 
 /** Free everything that is in the queue. */
 void CommandQueue::Free()
 {
 	std::unique_ptr<CommandPacket> cp;
-	while ((cp = this->Pop()) != NULL) {}
+	while ((cp = this->Pop()) != nullptr) {}
 	assert(this->count == 0);
 }
 
@@ -158,7 +158,7 @@ void NetworkSendCommand(TileIndex tile, uint32 p1, uint32 p2, uint32 cmd, Comman
 
 	c.binary_length = binary_length;
 	if (binary_length == 0) {
-		if (text != NULL) {
+		if (text != nullptr) {
 			c.text.assign(text);
 		} else {
 			c.text.clear();
@@ -198,7 +198,7 @@ void NetworkSendCommand(TileIndex tile, uint32 p1, uint32 p2, uint32 cmd, Comman
  */
 void NetworkSyncCommandQueue(NetworkClientSocket *cs)
 {
-	for (CommandPacket *p = _local_execution_queue.Peek(); p != NULL; p = p->next) {
+	for (CommandPacket *p = _local_execution_queue.Peek(); p != nullptr; p = p->next) {
 		CommandPacket c = *p;
 		c.callback = 0;
 		cs->outgoing_queue.Append(std::move(c));
@@ -215,7 +215,7 @@ void NetworkExecuteLocalCommandQueue()
 	CommandQueue &queue = (_network_server ? _local_execution_queue : ClientNetworkGameSocketHandler::my_client->incoming_queue);
 
 	CommandPacket *cp;
-	while ((cp = queue.Peek()) != NULL) {
+	while ((cp = queue.Peek()) != nullptr) {
 		/* The queue is always in order, which means
 		 * that the first element will be executed first. */
 		if (_frame_counter < cp->frame) break;
@@ -262,13 +262,13 @@ static void DistributeCommandPacket(CommandPacket &cp, const NetworkClientSocket
 		if (cs->status >= NetworkClientSocket::STATUS_MAP) {
 			/* Callbacks are only send back to the client who sent them in the
 			 *  first place. This filters that out. */
-			cp.callback = (cs != owner) ? NULL : callback;
+			cp.callback = (cs != owner) ? nullptr : callback;
 			cp.my_cmd = (cs == owner);
 			cs->outgoing_queue.Append(cp);
 		}
 	}
 
-	cp.callback = (cs != owner) ? NULL : callback;
+	cp.callback = (cs != owner) ? nullptr : callback;
 	cp.my_cmd = (cs == owner);
 	_local_execution_queue.Append(cp);
 }
@@ -288,7 +288,7 @@ static void DistributeQueue(CommandQueue *queue, const NetworkClientSocket *owne
 #endif
 
 	std::unique_ptr<CommandPacket> cp;
-	while (--to_go >= 0 && (cp = queue->Pop(true)) != NULL) {
+	while (--to_go >= 0 && (cp = queue->Pop(true)) != nullptr) {
 		DistributeCommandPacket(*cp, owner);
 		NetworkAdminCmdLogging(owner, cp.get());
 	}
@@ -298,7 +298,7 @@ static void DistributeQueue(CommandQueue *queue, const NetworkClientSocket *owne
 void NetworkDistributeCommands()
 {
 	/* First send the server's commands. */
-	DistributeQueue(&_local_wait_queue, NULL);
+	DistributeQueue(&_local_wait_queue, nullptr);
 
 	/* Then send the queues of the others. */
 	NetworkClientSocket *cs;
@@ -311,7 +311,7 @@ void NetworkDistributeCommands()
  * Receives a command from the network.
  * @param p the packet to read from.
  * @param cp the struct to write the data to.
- * @return an error message. When NULL there has been no error.
+ * @return an error message. When nullptr there has been no error.
  */
 const char *NetworkGameSocketHandler::ReceiveCommand(Packet *p, CommandPacket *cp)
 {
@@ -337,7 +337,7 @@ const char *NetworkGameSocketHandler::ReceiveCommand(Packet *p, CommandPacket *c
 	if (callback >= lengthof(_callback_table))  return "invalid callback";
 
 	cp->callback = _callback_table[callback];
-	return NULL;
+	return nullptr;
 }
 
 /**
@@ -367,7 +367,7 @@ void NetworkGameSocketHandler::SendCommand(Packet *p, const CommandPacket *cp)
 
 	if (callback == lengthof(_callback_table)) {
 		DEBUG(net, 0, "Unknown callback. (Pointer: %p) No callback sent", cp->callback);
-		callback = 0; // _callback_table[0] == NULL
+		callback = 0; // _callback_table[0] == nullptr
 	}
 	p->Send_uint8 (callback);
 }

src/network/network_content.cpp

@@ -35,7 +35,7 @@ ClientNetworkContentSocketHandler _network_content_client;
 /** Wrapper function for the HasProc */
 static bool HasGRFConfig(const ContentInfo *ci, bool md5sum)
 {
-	return FindGRFConfig(BSWAP32(ci->unique_id), md5sum ? FGCM_EXACT : FGCM_ANY, md5sum ? ci->md5sum : NULL) != NULL;
+	return FindGRFConfig(BSWAP32(ci->unique_id), md5sum ? FGCM_EXACT : FGCM_ANY, md5sum ? ci->md5sum : nullptr) != nullptr;
 }
 
 /**
@@ -79,7 +79,7 @@ bool ClientNetworkContentSocketHandler::Receive_SERVER_INFO(Packet *p)
 	}
 
 	/* Find the appropriate check function */
-	HasProc proc = NULL;
+	HasProc proc = nullptr;
 	switch (ci->type) {
 		case CONTENT_TYPE_NEWGRF:
 			proc = HasGRFConfig;
@@ -122,7 +122,7 @@ bool ClientNetworkContentSocketHandler::Receive_SERVER_INFO(Packet *p)
 			break;
 	}
 
-	if (proc != NULL) {
+	if (proc != nullptr) {
 		if (proc(ci, true)) {
 			ci->state = ContentInfo::ALREADY_HERE;
 		} else {
@@ -241,7 +241,7 @@ void ClientNetworkContentSocketHandler::RequestContentList(uint count, const Con
  */
 void ClientNetworkContentSocketHandler::RequestContentList(ContentVector *cv, bool send_md5sum)
 {
-	if (cv == NULL) return;
+	if (cv == nullptr) return;
 
 	this->Connect();
 
@@ -380,12 +380,12 @@ void ClientNetworkContentSocketHandler::DownloadSelectedContentFallback(const Co
  * @param ci         the information to get the filename from
  * @param compressed should the filename end with .gz?
  * @return a statically allocated buffer with the filename or
- *         NULL when no filename could be made.
+ *         nullptr when no filename could be made.
  */
 static char *GetFullFilename(const ContentInfo *ci, bool compressed)
 {
 	Subdirectory dir = GetContentInfoSubDir(ci->type);
-	if (dir == NO_DIRECTORY) return NULL;
+	if (dir == NO_DIRECTORY) return nullptr;
 
 	static char buf[MAX_PATH];
 	FioGetFullPath(buf, lastof(buf), SP_AUTODOWNLOAD_DIR, dir, ci->filename);
@@ -406,14 +406,14 @@ static bool GunzipFile(const ContentInfo *ci)
 
 	/* Need to open the file with fopen() to support non-ASCII on Windows. */
 	FILE *ftmp = fopen(GetFullFilename(ci, true), "rb");
-	if (ftmp == NULL) return false;
+	if (ftmp == nullptr) return false;
 	/* Duplicate the handle, and close the FILE*, to avoid double-closing the handle later. */
 	gzFile fin = gzdopen(dup(fileno(ftmp)), "rb");
 	fclose(ftmp);
 
 	FILE *fout = fopen(GetFullFilename(ci, false), "wb");
 
-	if (fin == NULL || fout == NULL) {
+	if (fin == nullptr || fout == nullptr) {
 		ret = false;
 	} else {
 		byte buff[8192];
@@ -447,8 +447,8 @@ static bool GunzipFile(const ContentInfo *ci)
 		}
 	}
 
-	if (fin != NULL) gzclose(fin);
-	if (fout != NULL) fclose(fout);
+	if (fin != nullptr) gzclose(fin);
+	if (fout != nullptr) fclose(fout);
 
 	return ret;
 #else
@@ -458,7 +458,7 @@ static bool GunzipFile(const ContentInfo *ci)
 
 bool ClientNetworkContentSocketHandler::Receive_SERVER_CONTENT(Packet *p)
 {
-	if (this->curFile == NULL) {
+	if (this->curFile == nullptr) {
 		delete this->curInfo;
 		/* When we haven't opened a file this must be our first packet with metadata. */
 		this->curInfo = new ContentInfo;
@@ -479,7 +479,7 @@ bool ClientNetworkContentSocketHandler::Receive_SERVER_CONTENT(Packet *p)
 			ShowErrorMessage(STR_CONTENT_ERROR_COULD_NOT_DOWNLOAD, STR_CONTENT_ERROR_COULD_NOT_DOWNLOAD_FILE_NOT_WRITABLE, WL_ERROR);
 			this->Close();
 			fclose(this->curFile);
-			this->curFile = NULL;
+			this->curFile = nullptr;
 
 			return false;
 		}
@@ -500,14 +500,14 @@ bool ClientNetworkContentSocketHandler::BeforeDownload()
 {
 	if (!this->curInfo->IsValid()) {
 		delete this->curInfo;
-		this->curInfo = NULL;
+		this->curInfo = nullptr;
 		return false;
 	}
 
 	if (this->curInfo->filesize != 0) {
 		/* The filesize is > 0, so we are going to download it */
 		const char *filename = GetFullFilename(this->curInfo, true);
-		if (filename == NULL || (this->curFile = fopen(filename, "wb")) == NULL) {
+		if (filename == nullptr || (this->curFile = fopen(filename, "wb")) == nullptr) {
 			/* Unless that fails of course... */
 			DeleteWindowById(WC_NETWORK_STATUS_WINDOW, WN_NETWORK_STATUS_WINDOW_CONTENT_DOWNLOAD);
 			ShowErrorMessage(STR_CONTENT_ERROR_COULD_NOT_DOWNLOAD, STR_CONTENT_ERROR_COULD_NOT_DOWNLOAD_FILE_NOT_WRITABLE, WL_ERROR);
@@ -526,7 +526,7 @@ void ClientNetworkContentSocketHandler::AfterDownload()
 	/* We read nothing; that's our marker for end-of-stream.
 	 * Now gunzip the tar and make it known. */
 	fclose(this->curFile);
-	this->curFile = NULL;
+	this->curFile = nullptr;
 
 	if (GunzipFile(this->curInfo)) {
 		unlink(GetFullFilename(this->curInfo, true));
@@ -560,25 +560,25 @@ void ClientNetworkContentSocketHandler::OnFailure()
 	this->http_response.shrink_to_fit();
 	this->http_response_index = -2;
 
-	if (this->curFile != NULL) {
+	if (this->curFile != nullptr) {
 		/* Revert the download progress when we are going for the old system. */
 		long size = ftell(this->curFile);
 		if (size > 0) this->OnDownloadProgress(this->curInfo, (int)-size);
 
 		fclose(this->curFile);
-		this->curFile = NULL;
+		this->curFile = nullptr;
 	}
 }
 
 void ClientNetworkContentSocketHandler::OnReceiveData(const char *data, size_t length)
 {
-	assert(data == NULL || length != 0);
+	assert(data == nullptr || length != 0);
 
 	/* Ignore any latent data coming from a connection we closed. */
 	if (this->http_response_index == -2) return;
 
 	if (this->http_response_index == -1) {
-		if (data != NULL) {
+		if (data != nullptr) {
 			/* Append the rest of the response. */
 			memcpy(grow(this->http_response, (uint)length), data, length);
 			return;
@@ -591,7 +591,7 @@ void ClientNetworkContentSocketHandler::OnReceiveData(const char *data, size_t l
 		}
 	}
 
-	if (data != NULL) {
+	if (data != nullptr) {
 		/* We have data, so write it to the file. */
 		if (fwrite(data, 1, length, this->curFile) != length) {
 			/* Writing failed somehow, let try via the old method. */
@@ -604,7 +604,7 @@ void ClientNetworkContentSocketHandler::OnReceiveData(const char *data, size_t l
 		return;
 	}
 
-	if (this->curFile != NULL) {
+	if (this->curFile != nullptr) {
 		/* We've finished downloading a file. */
 		this->AfterDownload();
 	}
@@ -622,7 +622,7 @@ void ClientNetworkContentSocketHandler::OnReceiveData(const char *data, size_t l
 	this->curInfo = new ContentInfo;
 
 /** Check p for not being null and return calling OnFailure if that's not the case. */
-#define check_not_null(p) { if ((p) == NULL) { this->OnFailure(); return; } }
+#define check_not_null(p) { if ((p) == nullptr) { this->OnFailure(); return; } }
 /** Check p for not being null and then terminate, or return calling OnFailure. */
 #define check_and_terminate(p) { check_not_null(p); *(p) = '\0'; }
 
@@ -701,8 +701,8 @@ void ClientNetworkContentSocketHandler::OnReceiveData(const char *data, size_t l
 ClientNetworkContentSocketHandler::ClientNetworkContentSocketHandler() :
 	NetworkContentSocketHandler(),
 	http_response_index(-2),
-	curFile(NULL),
-	curInfo(NULL),
+	curFile(nullptr),
+	curInfo(nullptr),
 	isConnecting(false),
 	lastActivity(_realtime_tick)
 {
@@ -712,7 +712,7 @@ ClientNetworkContentSocketHandler::ClientNetworkContentSocketHandler() :
 ClientNetworkContentSocketHandler::~ClientNetworkContentSocketHandler()
 {
 	delete this->curInfo;
-	if (this->curFile != NULL) fclose(this->curFile);
+	if (this->curFile != nullptr) fclose(this->curFile);
 
 	for (ContentInfo *ci : this->infos) delete ci;
 }
@@ -804,14 +804,14 @@ void ClientNetworkContentSocketHandler::DownloadContentInfo(ContentID cid)
 /**
  * Get the content info based on a ContentID
  * @param cid the ContentID to search for
- * @return the ContentInfo or NULL if not found
+ * @return the ContentInfo or nullptr if not found
  */
 ContentInfo *ClientNetworkContentSocketHandler::GetContent(ContentID cid)
 {
 	for (ContentInfo *ci : this->infos) {
 		if (ci->id == cid) return ci;
 	}
-	return NULL;
+	return nullptr;
 }
 
 
@@ -822,7 +822,7 @@ ContentInfo *ClientNetworkContentSocketHandler::GetContent(ContentID cid)
 void ClientNetworkContentSocketHandler::Select(ContentID cid)
 {
 	ContentInfo *ci = this->GetContent(cid);
-	if (ci == NULL || ci->state != ContentInfo::UNSELECTED) return;
+	if (ci == nullptr || ci->state != ContentInfo::UNSELECTED) return;
 
 	ci->state = ContentInfo::SELECTED;
 	this->CheckDependencyState(ci);
@@ -835,7 +835,7 @@ void ClientNetworkContentSocketHandler::Select(ContentID cid)
 void ClientNetworkContentSocketHandler::Unselect(ContentID cid)
 {
 	ContentInfo *ci = this->GetContent(cid);
-	if (ci == NULL || !ci->IsSelected()) return;
+	if (ci == nullptr || !ci->IsSelected()) return;
 
 	ci->state = ContentInfo::UNSELECTED;
 	this->CheckDependencyState(ci);
@@ -943,7 +943,7 @@ void ClientNetworkContentSocketHandler::CheckDependencyState(ContentInfo *ci)
 		 * selected and thus can unselect when a dependency is removed. */
 		for (uint i = 0; i < ci->dependency_count; i++) {
 			ContentInfo *c = this->GetContent(ci->dependencies[i]);
-			if (c == NULL) {
+			if (c == nullptr) {
 				this->DownloadContentInfo(ci->dependencies[i]);
 			} else if (c->state == ContentInfo::UNSELECTED) {
 				c->state = ContentInfo::AUTOSELECTED;
@@ -969,7 +969,7 @@ void ClientNetworkContentSocketHandler::CheckDependencyState(ContentInfo *ci)
 
 	for (uint i = 0; i < ci->dependency_count; i++) {
 		const ContentInfo *c = this->GetContent(ci->dependencies[i]);
-		if (c == NULL) {
+		if (c == nullptr) {
 			DownloadContentInfo(ci->dependencies[i]);
 			continue;
 		}
@@ -1074,7 +1074,7 @@ void ClientNetworkContentSocketHandler::OnDownloadProgress(const ContentInfo *ci
 void ClientNetworkContentSocketHandler::OnDownloadComplete(ContentID cid)
 {
 	ContentInfo *ci = this->GetContent(cid);
-	if (ci != NULL) {
+	if (ci != nullptr) {
 		ci->state = ContentInfo::ALREADY_HERE;
 	}
 

src/network/network_content.h

@@ -147,7 +147,7 @@ public:
 
 extern ClientNetworkContentSocketHandler _network_content_client;
 
-void ShowNetworkContentListWindow(ContentVector *cv = NULL, ContentType type1 = CONTENT_TYPE_END, ContentType type2 = CONTENT_TYPE_END);
+void ShowNetworkContentListWindow(ContentVector *cv = nullptr, ContentType type1 = CONTENT_TYPE_END, ContentType type2 = CONTENT_TYPE_END);
 
 void ShowMissingContentWindow(const struct GRFConfig *list);
 

src/network/network_content_gui.cpp

@@ -95,7 +95,7 @@ static const NWidgetPart _nested_network_content_download_status_window_widgets[
 
 /** Window description for the download window */
 static WindowDesc _network_content_download_status_window_desc(
-	WDP_CENTER, NULL, 0, 0,
+	WDP_CENTER, nullptr, 0, 0,
 	WC_NETWORK_STATUS_WINDOW, WC_NONE,
 	WDF_MODAL,
 	_nested_network_content_download_status_window_widgets, lengthof(_nested_network_content_download_status_window_widgets)
@@ -238,7 +238,7 @@ public:
 					break;
 
 				case CONTENT_TYPE_NEWGRF:
-					ScanNewGRFFiles(NULL);
+					ScanNewGRFFiles(nullptr);
 					break;
 
 				case CONTENT_TYPE_SCENARIO:
@@ -480,7 +480,7 @@ class NetworkContentListWindow : public Window, ContentCallback {
 		}
 
 		/* previously selected item not in list anymore */
-		this->selected = NULL;
+		this->selected = nullptr;
 		this->list_pos = 0;
 	}
 
@@ -501,7 +501,7 @@ class NetworkContentListWindow : public Window, ContentCallback {
 	/** Make sure that the currently selected content info is within the visible part of the matrix */
 	void ScrollToSelected()
 	{
-		if (this->selected == NULL) return;
+		if (this->selected == nullptr) return;
 
 		this->vscroll->ScrollTowards(this->list_pos);
 	}
@@ -521,7 +521,7 @@ public:
 			Window(desc),
 			auto_select(select_all),
 			filter_editbox(EDITBOX_MAX_SIZE),
-			selected(NULL),
+			selected(nullptr),
 			list_pos(0)
 	{
 		this->checkbox_size = maxdim(maxdim(GetSpriteSize(SPR_BOX_EMPTY), GetSpriteSize(SPR_BOX_CHECKED)), GetSpriteSize(SPR_BLOT));
@@ -685,7 +685,7 @@ public:
 		SetDParam(0, this->filesize_sum);
 		DrawString(r.left + DETAIL_LEFT, r.right - DETAIL_RIGHT, r.bottom - FONT_HEIGHT_NORMAL - WD_PAR_VSEP_NORMAL, STR_CONTENT_TOTAL_DOWNLOAD_SIZE);
 
-		if (this->selected == NULL) return;
+		if (this->selected == nullptr) return;
 
 		/* And fill the rest of the details when there's information to place there */
 		DrawStringMultiLine(r.left + WD_INSET_LEFT, r.right - WD_INSET_RIGHT, r.top + DETAIL_TITLE_HEIGHT / 2, r.top + DETAIL_TITLE_HEIGHT, STR_CONTENT_DETAIL_SUBTITLE_UNSELECTED + this->selected->state, TC_FROMSTRING, SA_CENTER);
@@ -779,7 +779,7 @@ public:
 	void OnClick(Point pt, int widget, int click_count) override
 	{
 		if (widget >= WID_NCL_TEXTFILE && widget < WID_NCL_TEXTFILE + TFT_END) {
-			if (this->selected == NULL || this->selected->state != ContentInfo::ALREADY_HERE) return;
+			if (this->selected == nullptr || this->selected->state != ContentInfo::ALREADY_HERE) return;
 
 			ShowContentTextfileWindow((TextfileType)(widget - WID_NCL_TEXTFILE), this->selected);
 			return;
@@ -842,14 +842,14 @@ public:
 				break;
 
 			case WID_NCL_OPEN_URL:
-				if (this->selected != NULL) {
+				if (this->selected != nullptr) {
 					extern void OpenBrowser(const char *url);
 					OpenBrowser(this->selected->url);
 				}
 				break;
 
 			case WID_NCL_DOWNLOAD:
-				if (BringWindowToFrontById(WC_NETWORK_STATUS_WINDOW, WN_NETWORK_STATUS_WINDOW_CONTENT_DOWNLOAD) == NULL) new NetworkContentDownloadStatusWindow();
+				if (BringWindowToFrontById(WC_NETWORK_STATUS_WINDOW, WN_NETWORK_STATUS_WINDOW_CONTENT_DOWNLOAD) == nullptr) new NetworkContentDownloadStatusWindow();
 				break;
 
 			case WID_NCL_SEARCH_EXTERNAL:
@@ -893,7 +893,7 @@ public:
 			case WKC_SPACE:
 			case WKC_RETURN:
 				if (keycode == WKC_RETURN || !IsWidgetFocused(WID_NCL_FILTER)) {
-					if (this->selected != NULL) {
+					if (this->selected != nullptr) {
 						_network_content_client.ToggleSelectedState(this->selected);
 						this->content.ForceResort();
 						this->InvalidateData();
@@ -1005,13 +1005,13 @@ public:
 		}
 
 		/* If data == 2 then the status window caused this OnInvalidate */
-		this->SetWidgetDisabledState(WID_NCL_DOWNLOAD, this->filesize_sum == 0 || (FindWindowById(WC_NETWORK_STATUS_WINDOW, WN_NETWORK_STATUS_WINDOW_CONTENT_DOWNLOAD) != NULL && data != 2));
+		this->SetWidgetDisabledState(WID_NCL_DOWNLOAD, this->filesize_sum == 0 || (FindWindowById(WC_NETWORK_STATUS_WINDOW, WN_NETWORK_STATUS_WINDOW_CONTENT_DOWNLOAD) != nullptr && data != 2));
 		this->SetWidgetDisabledState(WID_NCL_UNSELECT, this->filesize_sum == 0);
 		this->SetWidgetDisabledState(WID_NCL_SELECT_ALL, !show_select_all);
 		this->SetWidgetDisabledState(WID_NCL_SELECT_UPDATE, !show_select_upgrade);
-		this->SetWidgetDisabledState(WID_NCL_OPEN_URL, this->selected == NULL || StrEmpty(this->selected->url));
+		this->SetWidgetDisabledState(WID_NCL_OPEN_URL, this->selected == nullptr || StrEmpty(this->selected->url));
 		for (TextfileType tft = TFT_BEGIN; tft < TFT_END; tft++) {
-			this->SetWidgetDisabledState(WID_NCL_TEXTFILE + tft, this->selected == NULL || this->selected->state != ContentInfo::ALREADY_HERE || this->selected->GetTextfile(tft) == NULL);
+			this->SetWidgetDisabledState(WID_NCL_TEXTFILE + tft, this->selected == nullptr || this->selected->state != ContentInfo::ALREADY_HERE || this->selected->GetTextfile(tft) == nullptr);
 		}
 
 		this->GetWidget<NWidgetCore>(WID_NCL_CANCEL)->widget_data = this->filesize_sum == 0 ? STR_AI_SETTINGS_CLOSE : STR_AI_LIST_CANCEL;
@@ -1131,7 +1131,7 @@ static WindowDesc _network_content_list_desc(
 
 /**
  * Show the content list window with a given set of content
- * @param cv the content to show, or NULL when it has to search for itself
+ * @param cv the content to show, or nullptr when it has to search for itself
  * @param type1 the first type to (only) show or #CONTENT_TYPE_END to show all.
  * @param type2 the second type to (only) show in addition to type1. If type2 is != #CONTENT_TYPE_END, then also type1 should be != #CONTENT_TYPE_END.
  *   If type2 != #CONTENT_TYPE_END, then type1 != type2 must be true.
@@ -1141,7 +1141,7 @@ void ShowNetworkContentListWindow(ContentVector *cv, ContentType type1, ContentT
 #if defined(WITH_ZLIB)
 	std::bitset<CONTENT_TYPE_END> types;
 	_network_content_client.Clear();
-	if (cv == NULL) {
+	if (cv == nullptr) {
 		assert(type1 != CONTENT_TYPE_END || type2 == CONTENT_TYPE_END);
 		assert(type1 == CONTENT_TYPE_END || type1 != type2);
 		_network_content_client.RequestContentList(type1);
@@ -1154,11 +1154,11 @@ void ShowNetworkContentListWindow(ContentVector *cv, ContentType type1, ContentT
 	}
 
 	DeleteWindowById(WC_NETWORK_WINDOW, WN_NETWORK_WINDOW_CONTENT_LIST);
-	new NetworkContentListWindow(&_network_content_list_desc, cv != NULL, types);
+	new NetworkContentListWindow(&_network_content_list_desc, cv != nullptr, types);
 #else
 	ShowErrorMessage(STR_CONTENT_NO_ZLIB, STR_CONTENT_NO_ZLIB_SUB, WL_ERROR);
 	/* Connection failed... clean up the mess */
-	if (cv != NULL) {
+	if (cv != nullptr) {
 		for (ContentInfo *ci : *cv) delete ci;
 	}
 #endif /* WITH_ZLIB */

src/network/network_func.h

@@ -51,7 +51,7 @@ void NetworkPopulateCompanyStats(NetworkCompanyStats *stats);
 
 void NetworkUpdateClientInfo(ClientID client_id);
 void NetworkClientsToSpectators(CompanyID cid);
-void NetworkClientConnectGame(NetworkAddress address, CompanyID join_as, const char *join_server_password = NULL, const char *join_company_password = NULL);
+void NetworkClientConnectGame(NetworkAddress address, CompanyID join_as, const char *join_server_password = nullptr, const char *join_company_password = nullptr);
 void NetworkClientRequestMove(CompanyID company, const char *pass = "");
 void NetworkClientSendRcon(const char *password, const char *command);
 void NetworkClientSendChat(NetworkAction action, DestType type, int dest, const char *msg, NetworkTextMessageData data = NetworkTextMessageData());

src/network/network_gamelist.cpp

@@ -22,10 +22,10 @@
 
 #include "../safeguards.h"
 
-NetworkGameList *_network_game_list = NULL;
+NetworkGameList *_network_game_list = nullptr;
 
 /** The games to insert when the GUI thread has time for us. */
-static std::atomic<NetworkGameList *> _network_game_delayed_insertion_list(NULL);
+static std::atomic<NetworkGameList *> _network_game_delayed_insertion_list(nullptr);
 
 /**
  * Add a new item to the linked gamelist, but do it delayed in the next tick
@@ -43,12 +43,12 @@ static void NetworkGameListHandleDelayedInsert()
 {
 	while (true) {
 		NetworkGameList *ins_item = _network_game_delayed_insertion_list.load(std::memory_order_relaxed);
-		while (ins_item != NULL && !_network_game_delayed_insertion_list.compare_exchange_weak(ins_item, ins_item->next, std::memory_order_acq_rel)) {}
-		if (ins_item == NULL) break; // No item left.
+		while (ins_item != nullptr && !_network_game_delayed_insertion_list.compare_exchange_weak(ins_item, ins_item->next, std::memory_order_acq_rel)) {}
+		if (ins_item == nullptr) break; // No item left.
 
 		NetworkGameList *item = NetworkGameListAddItem(ins_item->address);
 
-		if (item != NULL) {
+		if (item != nullptr) {
 			if (StrEmpty(item->info.server_name)) {
 				ClearGRFConfigList(&item->info.grfconfig);
 				memset(&item->info, 0, sizeof(item->info));
@@ -78,22 +78,22 @@ NetworkGameList *NetworkGameListAddItem(NetworkAddress address)
 	if (StrEmpty(hostname) ||
 			strcmp(hostname, "0.0.0.0") == 0 ||
 			strcmp(hostname, "::") == 0) {
-		return NULL;
+		return nullptr;
 	}
 
 	NetworkGameList *item, *prev_item;
 
-	prev_item = NULL;
-	for (item = _network_game_list; item != NULL; item = item->next) {
+	prev_item = nullptr;
+	for (item = _network_game_list; item != nullptr; item = item->next) {
 		if (item->address == address) return item;
 		prev_item = item;
 	}
 
 	item = CallocT<NetworkGameList>(1);
-	item->next = NULL;
+	item->next = nullptr;
 	item->address = address;
 
-	if (prev_item == NULL) {
+	if (prev_item == nullptr) {
 		_network_game_list = item;
 	} else {
 		prev_item->next = item;
@@ -111,10 +111,10 @@ NetworkGameList *NetworkGameListAddItem(NetworkAddress address)
  */
 void NetworkGameListRemoveItem(NetworkGameList *remove)
 {
-	NetworkGameList *prev_item = NULL;
-	for (NetworkGameList *item = _network_game_list; item != NULL; item = item->next) {
+	NetworkGameList *prev_item = nullptr;
+	for (NetworkGameList *item = _network_game_list; item != nullptr; item = item->next) {
 		if (remove == item) {
-			if (prev_item == NULL) {
+			if (prev_item == nullptr) {
 				_network_game_list = remove->next;
 			} else {
 				prev_item->next = remove->next;
@@ -123,7 +123,7 @@ void NetworkGameListRemoveItem(NetworkGameList *remove)
 			/* Remove GRFConfig information */
 			ClearGRFConfigList(&remove->info.grfconfig);
 			free(remove);
-			remove = NULL;
+			remove = nullptr;
 
 			DEBUG(net, 4, "[gamelist] removed server from list");
 			NetworkRebuildHostList();
@@ -148,7 +148,7 @@ void NetworkGameListRequery()
 	if (++requery_cnt < REQUERY_EVERY_X_GAMELOOPS) return;
 	requery_cnt = 0;
 
-	for (NetworkGameList *item = _network_game_list; item != NULL; item = item->next) {
+	for (NetworkGameList *item = _network_game_list; item != nullptr; item = item->next) {
 		item->retries++;
 		if (item->retries < REFRESH_GAMEINFO_X_REQUERIES && (item->online || item->retries >= MAX_GAME_LIST_REQUERY_COUNT)) continue;
 
@@ -165,15 +165,15 @@ void NetworkGameListRequery()
  */
 void NetworkAfterNewGRFScan()
 {
-	for (NetworkGameList *item = _network_game_list; item != NULL; item = item->next) {
+	for (NetworkGameList *item = _network_game_list; item != nullptr; item = item->next) {
 		/* Reset compatibility state */
 		item->info.compatible = item->info.version_compatible;
 
-		for (GRFConfig *c = item->info.grfconfig; c != NULL; c = c->next) {
+		for (GRFConfig *c = item->info.grfconfig; c != nullptr; c = c->next) {
 			assert(HasBit(c->flags, GCF_COPY));
 
 			const GRFConfig *f = FindGRFConfig(c->ident.grfid, FGCM_EXACT, c->ident.md5sum);
-			if (f == NULL) {
+			if (f == nullptr) {
 				/* Don't know the GRF, so mark game incompatible and the (possibly)
 				 * already resolved name for this GRF (another server has sent the
 				 * name of the GRF already. */

src/network/network_gui.cpp

@@ -131,13 +131,13 @@ public:
 		this->resize_y = 0; // We never resize in this direction
 
 		/* First initialise some variables... */
-		for (NWidgetBase *child_wid = this->head; child_wid != NULL; child_wid = child_wid->next) {
+		for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
 			child_wid->SetupSmallestSize(w, init_array);
 			this->smallest_y = max(this->smallest_y, child_wid->smallest_y + child_wid->padding_top + child_wid->padding_bottom);
 		}
 
 		/* ... then in a second pass make sure the 'current' sizes are set. Won't change for most widgets. */
-		for (NWidgetBase *child_wid = this->head; child_wid != NULL; child_wid = child_wid->next) {
+		for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
 			child_wid->current_x = child_wid->smallest_x;
 			child_wid->current_y = this->smallest_y;
 		}
@@ -174,7 +174,7 @@ public:
 		uint position = 0; // Place to put next child relative to origin of the container.
 		uint i = rtl ? lengthof(this->visible) - 1 : 0;
 		child_wid = rtl ? this->tail : this->head;
-		while (child_wid != NULL) {
+		while (child_wid != nullptr) {
 			if (this->visible[i]) {
 				child_wid->AssignSizePosition(sizing, x + position, y, child_wid->current_x, this->current_y, rtl);
 				position += child_wid->current_x;
@@ -188,7 +188,7 @@ public:
 	void Draw(const Window *w) override
 	{
 		int i = 0;
-		for (NWidgetBase *child_wid = this->head; child_wid != NULL; child_wid = child_wid->next) {
+		for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
 			if (!this->visible[i++]) continue;
 
 			child_wid->Draw(w);
@@ -197,15 +197,15 @@ public:
 
 	NWidgetCore *GetWidgetFromPos(int x, int y) override
 	{
-		if (!IsInsideBS(x, this->pos_x, this->current_x) || !IsInsideBS(y, this->pos_y, this->current_y)) return NULL;
+		if (!IsInsideBS(x, this->pos_x, this->current_x) || !IsInsideBS(y, this->pos_y, this->current_y)) return nullptr;
 
 		int i = 0;
-		for (NWidgetBase *child_wid = this->head; child_wid != NULL; child_wid = child_wid->next) {
+		for (NWidgetBase *child_wid = this->head; child_wid != nullptr; child_wid = child_wid->next) {
 			if (!this->visible[i++]) continue;
 			NWidgetCore *nwid = child_wid->GetWidgetFromPos(x, y);
-			if (nwid != NULL) return nwid;
+			if (nwid != nullptr) return nwid;
 		}
-		return NULL;
+		return nullptr;
 	}
 
 	/**
@@ -254,7 +254,7 @@ protected:
 		/* Create temporary array of games to use for listing */
 		this->servers.clear();
 
-		for (NetworkGameList *ngl = _network_game_list; ngl != NULL; ngl = ngl->next) {
+		for (NetworkGameList *ngl = _network_game_list; ngl != nullptr; ngl = ngl->next) {
 			this->servers.push_back(ngl);
 		}
 
@@ -366,8 +366,8 @@ protected:
 
 	static bool CDECL NGameSearchFilter(NetworkGameList * const *item, StringFilter &sf)
 	{
-		assert(item != NULL);
-		assert((*item) != NULL);
+		assert(item != nullptr);
+		assert((*item) != nullptr);
 
 		sf.ResetState();
 		sf.AddLine((*item)->info.server_name);
@@ -462,7 +462,7 @@ public:
 	NetworkGameWindow(WindowDesc *desc) : Window(desc), name_editbox(NETWORK_CLIENT_NAME_LENGTH), filter_editbox(120)
 	{
 		this->list_pos = SLP_INVALID;
-		this->server = NULL;
+		this->server = nullptr;
 
 		this->lock_offset = 5;
 		this->blot_offset = this->lock_offset + 3 + GetSpriteSize(SPR_LOCK).width;
@@ -481,7 +481,7 @@ public:
 
 		this->last_joined = NetworkGameListAddItem(NetworkAddress(_settings_client.network.last_host, _settings_client.network.last_port));
 		this->server = this->last_joined;
-		if (this->last_joined != NULL) NetworkUDPQueryServer(this->last_joined->address);
+		if (this->last_joined != nullptr) NetworkUDPQueryServer(this->last_joined->address);
 
 		this->requery_timer.SetInterval(MILLISECONDS_PER_TICK);
 
@@ -578,7 +578,7 @@ public:
 
 			case WID_NG_LASTJOINED:
 				/* Draw the last joined server, if any */
-				if (this->last_joined != NULL) this->DrawServerLine(this->last_joined, r.top, this->last_joined == this->server);
+				if (this->last_joined != nullptr) this->DrawServerLine(this->last_joined, r.top, this->last_joined == this->server);
 				break;
 
 			case WID_NG_DETAILS:
@@ -608,16 +608,16 @@ public:
 
 		NetworkGameList *sel = this->server;
 		/* 'Refresh' button invisible if no server selected */
-		this->SetWidgetDisabledState(WID_NG_REFRESH, sel == NULL);
+		this->SetWidgetDisabledState(WID_NG_REFRESH, sel == nullptr);
 		/* 'Join' button disabling conditions */
-		this->SetWidgetDisabledState(WID_NG_JOIN, sel == NULL || // no Selected Server
+		this->SetWidgetDisabledState(WID_NG_JOIN, sel == nullptr || // no Selected Server
 				!sel->online || // Server offline
 				sel->info.clients_on >= sel->info.clients_max || // Server full
 				!sel->info.compatible); // Revision mismatch
 
 		/* 'NewGRF Settings' button invisible if no NewGRF is used */
-		this->GetWidget<NWidgetStacked>(WID_NG_NEWGRF_SEL)->SetDisplayedPlane(sel == NULL || !sel->online || sel->info.grfconfig == NULL);
-		this->GetWidget<NWidgetStacked>(WID_NG_NEWGRF_MISSING_SEL)->SetDisplayedPlane(sel == NULL || !sel->online || sel->info.grfconfig == NULL || !sel->info.version_compatible || sel->info.compatible);
+		this->GetWidget<NWidgetStacked>(WID_NG_NEWGRF_SEL)->SetDisplayedPlane(sel == nullptr || !sel->online || sel->info.grfconfig == nullptr);
+		this->GetWidget<NWidgetStacked>(WID_NG_NEWGRF_MISSING_SEL)->SetDisplayedPlane(sel == nullptr || !sel->online || sel->info.grfconfig == nullptr || !sel->info.version_compatible || sel->info.compatible);
 
 		this->DrawWidgets();
 	}
@@ -630,7 +630,7 @@ public:
 
 		/* Draw the right menu */
 		GfxFillRect(r.left + 1, r.top + 1, r.right - 1, r.top + detail_height - 1, PC_DARK_BLUE);
-		if (sel == NULL) {
+		if (sel == nullptr) {
 			DrawString(r.left + WD_FRAMERECT_LEFT, r.right - WD_FRAMERECT_RIGHT, r.top + 6 + 4 + FONT_HEIGHT_NORMAL, STR_NETWORK_SERVER_LIST_GAME_INFO, TC_FROMSTRING, SA_HOR_CENTER);
 		} else if (!sel->online) {
 			DrawString(r.left + WD_FRAMERECT_LEFT, r.right - WD_FRAMERECT_RIGHT, r.top + 6 + 4 + FONT_HEIGHT_NORMAL, sel->info.server_name, TC_ORANGE, SA_HOR_CENTER); // game name
@@ -724,8 +724,8 @@ public:
 
 			case WID_NG_MATRIX: { // Show available network games
 				uint id_v = this->vscroll->GetScrolledRowFromWidget(pt.y, this, WID_NG_MATRIX);
-				this->server = (id_v < this->servers.size()) ? this->servers[id_v] : NULL;
-				this->list_pos = (server == NULL) ? SLP_INVALID : id_v;
+				this->server = (id_v < this->servers.size()) ? this->servers[id_v] : nullptr;
+				this->list_pos = (server == nullptr) ? SLP_INVALID : id_v;
 				this->SetDirty();
 
 				/* FIXME the disabling should go into some InvalidateData, which is called instead of the SetDirty */
@@ -734,7 +734,7 @@ public:
 			}
 
 			case WID_NG_LASTJOINED: {
-				if (this->last_joined != NULL) {
+				if (this->last_joined != nullptr) {
 					this->server = this->last_joined;
 
 					/* search the position of the newly selected server */
@@ -769,7 +769,7 @@ public:
 				break;
 
 			case WID_NG_JOIN: // Join Game
-				if (this->server != NULL) {
+				if (this->server != nullptr) {
 					seprintf(_settings_client.network.last_host, lastof(_settings_client.network.last_host), "%s", this->server->address.GetHostname());
 					_settings_client.network.last_port = this->server->address.GetPort();
 					ShowNetworkLobbyWindow(this->server);
@@ -777,15 +777,15 @@ public:
 				break;
 
 			case WID_NG_REFRESH: // Refresh
-				if (this->server != NULL) NetworkUDPQueryServer(this->server->address);
+				if (this->server != nullptr) NetworkUDPQueryServer(this->server->address);
 				break;
 
 			case WID_NG_NEWGRF: // NewGRF Settings
-				if (this->server != NULL) ShowNewGRFSettings(false, false, false, &this->server->info.grfconfig);
+				if (this->server != nullptr) ShowNewGRFSettings(false, false, false, &this->server->info.grfconfig);
 				break;
 
 			case WID_NG_NEWGRF_MISSING: // Find missing content online
-				if (this->server != NULL) ShowMissingContentWindow(this->server->info.grfconfig);
+				if (this->server != nullptr) ShowMissingContentWindow(this->server->info.grfconfig);
 				break;
 		}
 	}
@@ -864,11 +864,11 @@ public:
 			return ES_HANDLED;
 		}
 
-		if (this->server != NULL) {
+		if (this->server != nullptr) {
 			if (keycode == WKC_DELETE) { // Press 'delete' to remove servers
 				NetworkGameListRemoveItem(this->server);
-				if (this->server == this->last_joined) this->last_joined = NULL;
-				this->server = NULL;
+				if (this->server == this->last_joined) this->last_joined = nullptr;
+				this->server = nullptr;
 				this->list_pos = SLP_INVALID;
 			}
 		}
@@ -1246,7 +1246,7 @@ struct NetworkStartServerWindow : public Window {
 
 	void OnQueryTextFinished(char *str) override
 	{
-		if (str == NULL) return;
+		if (str == nullptr) return;
 
 		if (this->widget_id == WID_NSS_SETPWD) {
 			strecpy(_settings_client.network.server_password, str, lastof(_settings_client.network.server_password));
@@ -1346,7 +1346,7 @@ static const NWidgetPart _nested_network_start_server_window_widgets[] = {
 };
 
 static WindowDesc _network_start_server_window_desc(
-	WDP_CENTER, NULL, 0, 0,
+	WDP_CENTER, nullptr, 0, 0,
 	WC_NETWORK_WINDOW, WC_NONE,
 	0,
 	_nested_network_start_server_window_widgets, lengthof(_nested_network_start_server_window_widgets)
@@ -1633,7 +1633,7 @@ static const NWidgetPart _nested_network_lobby_window_widgets[] = {
 };
 
 static WindowDesc _network_lobby_window_desc(
-	WDP_CENTER, NULL, 0, 0,
+	WDP_CENTER, nullptr, 0, 0,
 	WC_NETWORK_WINDOW, WC_NONE,
 	0,
 	_nested_network_lobby_window_widgets, lengthof(_nested_network_lobby_window_widgets)
@@ -1662,7 +1662,7 @@ static void ShowNetworkLobbyWindow(NetworkGameList *ngl)
 NetworkCompanyInfo *GetLobbyCompanyInfo(CompanyID company)
 {
 	NetworkLobbyWindow *lobby = dynamic_cast<NetworkLobbyWindow*>(FindWindowById(WC_NETWORK_WINDOW, WN_NETWORK_WINDOW_LOBBY));
-	return (lobby != NULL && company < MAX_COMPANIES) ? &lobby->company_info[company] : NULL;
+	return (lobby != nullptr && company < MAX_COMPANIES) ? &lobby->company_info[company] : nullptr;
 }
 
 /* The window below gives information about the connected clients
@@ -1681,7 +1681,7 @@ static const NWidgetPart _nested_client_list_popup_widgets[] = {
 };
 
 static WindowDesc _client_list_popup_desc(
-	WDP_AUTO, NULL, 0, 0,
+	WDP_AUTO, nullptr, 0, 0,
 	WC_CLIENT_LIST_POPUP, WC_CLIENT_LIST,
 	0,
 	_nested_client_list_popup_widgets, lengthof(_nested_client_list_popup_widgets)
@@ -1814,7 +1814,7 @@ struct NetworkClientListPopupWindow : Window {
 		} else {
 			if (index < this->actions.size() && _cursor.pos.y >= this->top) {
 				const NetworkClientInfo *ci = NetworkClientInfo::GetByClientID(this->client_id);
-				if (ci != NULL) this->actions[index].proc(ci);
+				if (ci != nullptr) this->actions[index].proc(ci);
 			}
 
 			DeleteWindowByClass(WC_CLIENT_LIST_POPUP);
@@ -1829,7 +1829,7 @@ static void PopupClientList(ClientID client_id, int x, int y)
 {
 	DeleteWindowByClass(WC_CLIENT_LIST_POPUP);
 
-	if (NetworkClientInfo::GetByClientID(client_id) == NULL) return;
+	if (NetworkClientInfo::GetByClientID(client_id) == nullptr) return;
 
 	new NetworkClientListPopupWindow(&_client_list_popup_desc, x, y, client_id);
 }
@@ -1975,7 +1975,7 @@ struct NetworkClientListWindow : Window {
 				client_no--;
 			}
 
-			if (ci != NULL) PopupClientList(ci->client_id, pt.x + this->left, pt.y + this->top);
+			if (ci != nullptr) PopupClientList(ci->client_id, pt.x + this->left, pt.y + this->top);
 		}
 	}
 
@@ -2122,7 +2122,7 @@ static const NWidgetPart _nested_network_join_status_window_widgets[] = {
 };
 
 static WindowDesc _network_join_status_window_desc(
-	WDP_CENTER, NULL, 0, 0,
+	WDP_CENTER, nullptr, 0, 0,
 	WC_NETWORK_STATUS_WINDOW, WC_NONE,
 	WDF_MODAL,
 	_nested_network_join_status_window_widgets, lengthof(_nested_network_join_status_window_widgets)
@@ -2137,7 +2137,7 @@ void ShowJoinStatusWindow()
 void ShowNetworkNeedPassword(NetworkPasswordType npt)
 {
 	NetworkJoinStatusWindow *w = (NetworkJoinStatusWindow *)FindWindowById(WC_NETWORK_STATUS_WINDOW, WN_NETWORK_STATUS_WINDOW_JOIN);
-	if (w == NULL) return;
+	if (w == nullptr) return;
 	w->password_type = npt;
 
 	StringID caption;
@@ -2216,7 +2216,7 @@ static const NWidgetPart _nested_network_company_password_window_widgets[] = {
 };
 
 static WindowDesc _network_company_password_window_desc(
-	WDP_AUTO, NULL, 0, 0,
+	WDP_AUTO, nullptr, 0, 0,
 	WC_COMPANY_PASSWORD_WINDOW, WC_NONE,
 	0,
 	_nested_network_company_password_window_widgets, lengthof(_nested_network_company_password_window_widgets)

src/network/network_internal.h

@@ -149,8 +149,8 @@ bool IsNetworkCompatibleVersion(const char *version, bool extended = false);
  * Everything we need to know about a command to be able to execute it.
  */
 struct CommandPacket : CommandContainer {
-	/** Make sure the pointer is NULL. */
-	CommandPacket() : next(NULL), company(INVALID_COMPANY), frame(0), my_cmd(false) {}
+	/** Make sure the pointer is nullptr. */
+	CommandPacket() : next(nullptr), company(INVALID_COMPANY), frame(0), my_cmd(false) {}
 	CommandPacket *next; ///< the next command packet (if in queue)
 	CompanyID company;   ///< company that is executing the command
 	uint32 frame;        ///< the frame in which this packet is executed

src/network/network_server.cpp

@@ -71,7 +71,7 @@ struct PacketWriter : SaveFilter {
 	 * Create the packet writer.
 	 * @param cs The socket handler we're making the packets for.
 	 */
-	PacketWriter(ServerNetworkGameSocketHandler *cs) : SaveFilter(NULL), cs(cs), current(NULL), total_size(0), packets(NULL)
+	PacketWriter(ServerNetworkGameSocketHandler *cs) : SaveFilter(nullptr), cs(cs), current(nullptr), total_size(0), packets(nullptr)
 	{
 	}
 
@@ -80,11 +80,11 @@ struct PacketWriter : SaveFilter {
 	{
 		std::unique_lock<std::mutex> lock(this->mutex);
 
-		if (this->cs != NULL) this->exit_sig.wait(lock);
+		if (this->cs != nullptr) this->exit_sig.wait(lock);
 
 		/* This must all wait until the Destroy function is called. */
 
-		while (this->packets != NULL) {
+		while (this->packets != nullptr) {
 			Packet *p = this->packets->next;
 			delete this->packets;
 			this->packets = p;
@@ -97,7 +97,7 @@ struct PacketWriter : SaveFilter {
 	 * Begin the destruction of this packet writer. It can happen in two ways:
 	 * in the first case the client disconnected while saving the map. In this
 	 * case the saving has not finished and killed this PacketWriter. In that
-	 * case we simply set cs to NULL, triggering the appending to fail due to
+	 * case we simply set cs to nullptr, triggering the appending to fail due to
 	 * the connection problem and eventually triggering the destructor. In the
 	 * second case the destructor is already called, and it is waiting for our
 	 * signal which we will send. Only then the packets will be removed by the
@@ -107,7 +107,7 @@ struct PacketWriter : SaveFilter {
 	{
 		std::unique_lock<std::mutex> lock(this->mutex);
 
-		this->cs = NULL;
+		this->cs = nullptr;
 
 		this->exit_sig.notify_all();
 		lock.unlock();
@@ -128,7 +128,7 @@ struct PacketWriter : SaveFilter {
 	 */
 	bool HasPackets()
 	{
-		return this->packets != NULL;
+		return this->packets != nullptr;
 	}
 
 	/**
@@ -140,7 +140,7 @@ struct PacketWriter : SaveFilter {
 
 		Packet *p = this->packets;
 		this->packets = p->next;
-		p->next = NULL;
+		p->next = nullptr;
 
 		return p;
 	}
@@ -148,23 +148,23 @@ struct PacketWriter : SaveFilter {
 	/** Append the current packet to the queue. */
 	void AppendQueue()
 	{
-		if (this->current == NULL) return;
+		if (this->current == nullptr) return;
 
 		Packet **p = &this->packets;
-		while (*p != NULL) {
+		while (*p != nullptr) {
 			p = &(*p)->next;
 		}
 		*p = this->current;
 
-		this->current = NULL;
+		this->current = nullptr;
 	}
 
 	void Write(byte *buf, size_t size) override
 	{
 		/* We want to abort the saving when the socket is closed. */
-		if (this->cs == NULL) SlError(STR_NETWORK_ERROR_LOSTCONNECTION);
+		if (this->cs == nullptr) SlError(STR_NETWORK_ERROR_LOSTCONNECTION);
 
-		if (this->current == NULL) this->current = new Packet(PACKET_SERVER_MAP_DATA);
+		if (this->current == nullptr) this->current = new Packet(PACKET_SERVER_MAP_DATA);
 
 		std::lock_guard<std::mutex> lock(this->mutex);
 
@@ -187,7 +187,7 @@ struct PacketWriter : SaveFilter {
 	void Finish() override
 	{
 		/* We want to abort the saving when the socket is closed. */
-		if (this->cs == NULL) SlError(STR_NETWORK_ERROR_LOSTCONNECTION);
+		if (this->cs == nullptr) SlError(STR_NETWORK_ERROR_LOSTCONNECTION);
 
 		std::lock_guard<std::mutex> lock(this->mutex);
 
@@ -230,9 +230,9 @@ ServerNetworkGameSocketHandler::~ServerNetworkGameSocketHandler()
 	if (_redirect_console_to_client == this->client_id) _redirect_console_to_client = INVALID_CLIENT_ID;
 	OrderBackup::ResetUser(this->client_id);
 
-	if (this->savegame != NULL) {
+	if (this->savegame != nullptr) {
 		this->savegame->Destroy();
-		this->savegame = NULL;
+		this->savegame = nullptr;
 	}
 }
 
@@ -240,12 +240,12 @@ Packet *ServerNetworkGameSocketHandler::ReceivePacket()
 {
 	/* Only allow receiving when we have some buffer free; this value
 	 * can go negative, but eventually it will become positive again. */
-	if (this->receive_limit <= 0) return NULL;
+	if (this->receive_limit <= 0) return nullptr;
 
 	/* We can receive a packet, so try that and if needed account for
 	 * the amount of received data. */
 	Packet *p = this->NetworkTCPSocketHandler::ReceivePacket();
-	if (p != NULL) this->receive_limit -= p->size;
+	if (p != nullptr) this->receive_limit -= p->size;
 	return p;
 }
 
@@ -268,7 +268,7 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::CloseConnection(NetworkRecvSta
 
 		this->GetClientName(client_name, lastof(client_name));
 
-		NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, client_name, NULL, STR_NETWORK_ERROR_CLIENT_CONNECTION_LOST);
+		NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, client_name, nullptr, STR_NETWORK_ERROR_CLIENT_CONNECTION_LOST);
 
 		/* Inform other clients of this... strange leaving ;) */
 		FOR_ALL_CLIENT_SOCKETS(new_cs) {
@@ -365,7 +365,7 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::SendCompanyInfo()
 
 	/* Add the local player (if not dedicated) */
 	const NetworkClientInfo *ci = NetworkClientInfo::GetByClientID(CLIENT_ID_SERVER);
-	if (ci != NULL && Company::IsValidID(ci->client_playas)) {
+	if (ci != nullptr && Company::IsValidID(ci->client_playas)) {
 		strecpy(clients[ci->client_playas], ci->client_name, lastof(clients[ci->client_playas]));
 	}
 
@@ -375,7 +375,7 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::SendCompanyInfo()
 		((ServerNetworkGameSocketHandler*)csi)->GetClientName(client_name, lastof(client_name));
 
 		ci = csi->GetInfo();
-		if (ci != NULL && Company::IsValidID(ci->client_playas)) {
+		if (ci != nullptr && Company::IsValidID(ci->client_playas)) {
 			if (!StrEmpty(clients[ci->client_playas])) {
 				strecat(clients[ci->client_playas], ", ", lastof(clients[ci->client_playas]));
 			}
@@ -438,7 +438,7 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::SendError(NetworkErrorCode err
 
 		DEBUG(net, 1, "'%s' made an error and has been disconnected. Reason: '%s'", client_name, str);
 
-		NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, client_name, NULL, strid);
+		NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, client_name, nullptr, strid);
 
 		FOR_ALL_CLIENT_SOCKETS(new_cs) {
 			if (new_cs->status > STATUS_AUTHORIZED && new_cs != this) {
@@ -467,12 +467,12 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::SendNewGRFCheck()
 	const GRFConfig *c;
 	uint grf_count = 0;
 
-	for (c = _grfconfig; c != NULL; c = c->next) {
+	for (c = _grfconfig; c != nullptr; c = c->next) {
 		if (!HasBit(c->flags, GCF_STATIC)) grf_count++;
 	}
 
 	p->Send_uint32 (grf_count);
-	for (c = _grfconfig; c != NULL; c = c->next) {
+	for (c = _grfconfig; c != nullptr; c = c->next) {
 		if (!HasBit(c->flags, GCF_STATIC)) this->SendGRFIdentifier(p, &c->ident);
 	}
 
@@ -611,7 +611,7 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::SendMap()
 		if (last_packet) {
 			/* Done reading, make sure saving is done as well */
 			this->savegame->Destroy();
-			this->savegame = NULL;
+			this->savegame = nullptr;
 
 			/* Set the status to DONE_MAP, no we will wait for the client
 			 *  to send it is ready (maybe that happens like never ;)) */
@@ -619,17 +619,17 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::SendMap()
 
 			/* Find the best candidate for joining, i.e. the first joiner. */
 			NetworkClientSocket *new_cs;
-			NetworkClientSocket *best = NULL;
+			NetworkClientSocket *best = nullptr;
 			FOR_ALL_CLIENT_SOCKETS(new_cs) {
 				if (new_cs->status == STATUS_MAP_WAIT) {
-					if (best == NULL || best->GetInfo()->join_date > new_cs->GetInfo()->join_date || (best->GetInfo()->join_date == new_cs->GetInfo()->join_date && best->client_id > new_cs->client_id)) {
+					if (best == nullptr || best->GetInfo()->join_date > new_cs->GetInfo()->join_date || (best->GetInfo()->join_date == new_cs->GetInfo()->join_date && best->client_id > new_cs->client_id)) {
 						best = new_cs;
 					}
 				}
 			}
 
 			/* Is there someone else to join? */
-			if (best != NULL) {
+			if (best != nullptr) {
 				/* Let the first start joining. */
 				best->status = STATUS_AUTHORIZED;
 				best->SendMap();
@@ -950,9 +950,9 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_JOIN(Packet *p)
 
 	this->status = STATUS_NEWGRFS_CHECK;
 
-	if (_grfconfig == NULL) {
+	if (_grfconfig == nullptr) {
 		/* Behave as if we received PACKET_CLIENT_NEWGRFS_CHECKED */
-		return this->Receive_CLIENT_NEWGRFS_CHECKED(NULL);
+		return this->Receive_CLIENT_NEWGRFS_CHECKED(nullptr);
 	}
 
 	return this->SendNewGRFCheck();
@@ -1036,7 +1036,7 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_MAP_OK(Packet *
 
 		this->GetClientName(client_name, lastof(client_name));
 
-		NetworkTextMessage(NETWORK_ACTION_JOIN, CC_DEFAULT, false, client_name, NULL, this->client_id);
+		NetworkTextMessage(NETWORK_ACTION_JOIN, CC_DEFAULT, false, client_name, nullptr, this->client_id);
 
 		/* Mark the client as pre-active, and wait for an ACK
 		 *  so we know he is done loading and in sync with us */
@@ -1093,7 +1093,7 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_COMMAND(Packet
 
 	NetworkClientInfo *ci = this->GetInfo();
 
-	if (err != NULL) {
+	if (err != nullptr) {
 		IConsolePrintF(CC_ERROR, "WARNING: %s from client %d (IP: %s).", err, ci->client_id, this->GetClientIP());
 		return this->SendError(NETWORK_ERROR_NOT_EXPECTED);
 	}
@@ -1159,7 +1159,7 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_ERROR(Packet *p
 
 	DEBUG(net, 2, "'%s' reported an error and is closing its connection (%s)", client_name, str);
 
-	NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, client_name, NULL, strid);
+	NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, client_name, nullptr, strid);
 
 	FOR_ALL_CLIENT_SOCKETS(new_cs) {
 		if (new_cs->status > STATUS_AUTHORIZED) {
@@ -1171,7 +1171,7 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_ERROR(Packet *p
 
 	if (errorno == NETWORK_ERROR_DESYNC) {
 		// have the server and all clients run some sanity checks
-		NetworkSendCommand(0, 0, 0, CMD_DESYNC_CHECK, NULL, NULL, _local_company, 0);
+		NetworkSendCommand(0, 0, 0, CMD_DESYNC_CHECK, nullptr, nullptr, _local_company, 0);
 	}
 
 	return this->CloseConnection(NETWORK_RECV_STATUS_CONN_LOST);
@@ -1191,7 +1191,7 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_QUIT(Packet *p)
 
 	this->GetClientName(client_name, lastof(client_name));
 
-	NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, client_name, NULL, STR_NETWORK_MESSAGE_CLIENT_LEAVING);
+	NetworkTextMessage(NETWORK_ACTION_LEAVE, CC_DEFAULT, false, client_name, nullptr, STR_NETWORK_MESSAGE_CLIENT_LEAVING);
 
 	FOR_ALL_CLIENT_SOCKETS(new_cs) {
 		if (new_cs->status > STATUS_AUTHORIZED && new_cs != this) {
@@ -1271,7 +1271,7 @@ void NetworkServerSendChat(NetworkAction action, DestType desttype, int dest, co
 			if ((ClientID)dest == CLIENT_ID_SERVER) {
 				ci = NetworkClientInfo::GetByClientID(from_id);
 				/* Display the text locally, and that is it */
-				if (ci != NULL) {
+				if (ci != nullptr) {
 					NetworkTextMessage(action, GetDrawStringCompanyColour(ci->client_playas), false, ci->client_name, msg, data);
 
 					if (_settings_client.network.server_admin_chat) {
@@ -1293,7 +1293,7 @@ void NetworkServerSendChat(NetworkAction action, DestType desttype, int dest, co
 				if (from_id == CLIENT_ID_SERVER) {
 					ci = NetworkClientInfo::GetByClientID(from_id);
 					ci_to = NetworkClientInfo::GetByClientID((ClientID)dest);
-					if (ci != NULL && ci_to != NULL) {
+					if (ci != nullptr && ci_to != nullptr) {
 						NetworkTextMessage(action, GetDrawStringCompanyColour(ci->client_playas), true, ci_to->client_name, msg, data);
 					}
 				} else {
@@ -1310,10 +1310,10 @@ void NetworkServerSendChat(NetworkAction action, DestType desttype, int dest, co
 			/* If this is false, the message is already displayed on the client who sent it. */
 			bool show_local = true;
 			/* Find all clients that belong to this company */
-			ci_to = NULL;
+			ci_to = nullptr;
 			FOR_ALL_CLIENT_SOCKETS(cs) {
 				ci = cs->GetInfo();
-				if (ci != NULL && ci->client_playas == (CompanyID)dest) {
+				if (ci != nullptr && ci->client_playas == (CompanyID)dest) {
 					cs->SendChat(action, from_id, false, msg, data);
 					if (cs->client_id == from_id) show_local = false;
 					ci_to = ci; // Remember a client that is in the company for company-name
@@ -1327,17 +1327,17 @@ void NetworkServerSendChat(NetworkAction action, DestType desttype, int dest, co
 
 			ci = NetworkClientInfo::GetByClientID(from_id);
 			ci_own = NetworkClientInfo::GetByClientID(CLIENT_ID_SERVER);
-			if (ci != NULL && ci_own != NULL && ci_own->client_playas == dest) {
+			if (ci != nullptr && ci_own != nullptr && ci_own->client_playas == dest) {
 				NetworkTextMessage(action, GetDrawStringCompanyColour(ci->client_playas), false, ci->client_name, msg, data);
 				if (from_id == CLIENT_ID_SERVER) show_local = false;
 				ci_to = ci_own;
 			}
 
 			/* There is no such client */
-			if (ci_to == NULL) break;
+			if (ci_to == nullptr) break;
 
 			/* Display the message locally (so you know you have sent it) */
-			if (ci != NULL && show_local) {
+			if (ci != nullptr && show_local) {
 				if (from_id == CLIENT_ID_SERVER) {
 					char name[NETWORK_NAME_LENGTH];
 					StringID str = Company::IsValidID(ci_to->client_playas) ? STR_COMPANY_NAME : STR_NETWORK_SPECTATORS;
@@ -1367,7 +1367,7 @@ void NetworkServerSendChat(NetworkAction action, DestType desttype, int dest, co
 			NetworkAdminChat(action, desttype, from_id, msg, data, from_admin);
 
 			ci = NetworkClientInfo::GetByClientID(from_id);
-			if (ci != NULL) {
+			if (ci != nullptr) {
 				NetworkTextMessage(action, GetDrawStringCompanyColour(ci->client_playas),
 						(desttype == DESTTYPE_BROADCAST_SS && from_id == CLIENT_ID_SERVER), ci->client_name, msg, data);
 			}
@@ -1440,7 +1440,7 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_SET_NAME(Packet
 
 	if (this->HasClientQuit()) return NETWORK_RECV_STATUS_CONN_LOST;
 
-	if (ci != NULL) {
+	if (ci != nullptr) {
 		/* Display change */
 		if (NetworkFindName(client_name, lastof(client_name))) {
 			NetworkTextMessage(NETWORK_ACTION_NAME_CHANGE, CC_DEFAULT, false, ci->client_name, client_name);
@@ -1603,7 +1603,7 @@ void NetworkUpdateClientInfo(ClientID client_id)
 	NetworkClientSocket *cs;
 	NetworkClientInfo *ci = NetworkClientInfo::GetByClientID(client_id);
 
-	if (ci == NULL) return;
+	if (ci == nullptr) return;
 
 	DEBUG(desync, 1, "client: date{%08x; %02x; %02x}; %02x; %04x", _date, _date_fract, _tick_skip_counter, (int)ci->client_playas, client_id);
 
@@ -1724,7 +1724,7 @@ bool NetworkFindName(char *new_name, const char *last)
 		}
 		/* Check if it is the same as the server-name */
 		ci = NetworkClientInfo::GetByClientID(CLIENT_ID_SERVER);
-		if (ci != NULL) {
+		if (ci != nullptr) {
 			if (strcmp(ci->client_name, new_name) == 0) found_name = false; // name already in use
 		}
 
@@ -1755,7 +1755,7 @@ bool NetworkServerChangeClientName(ClientID client_id, const char *new_name)
 	}
 
 	ci = NetworkClientInfo::GetByClientID(client_id);
-	if (ci == NULL) return false;
+	if (ci == nullptr) return false;
 
 	NetworkTextMessage(NETWORK_ACTION_NAME_CHANGE, CC_DEFAULT, true, ci->client_name, new_name);
 
@@ -1790,7 +1790,7 @@ void NetworkServerSetCompanyPassword(CompanyID company_id, const char *password,
 static void NetworkHandleCommandQueue(NetworkClientSocket *cs)
 {
 	std::unique_ptr<CommandPacket> cp;
-	while ((cp = cs->outgoing_queue.Pop()) != NULL) {
+	while ((cp = cs->outgoing_queue.Pop()) != nullptr) {
 		cs->SendCommand(cp.get());
 	}
 }
@@ -1975,7 +1975,7 @@ void NetworkServerShowStatusToConsole()
 	NetworkClientSocket *cs;
 	FOR_ALL_CLIENT_SOCKETS(cs) {
 		NetworkClientInfo *ci = cs->GetInfo();
-		if (ci == NULL) continue;
+		if (ci == nullptr) continue;
 		uint lag = NetworkCalculateLag(cs);
 		const char *status;
 
@@ -2142,7 +2142,7 @@ void ServerNetworkGameSocketHandler::GetClientName(char *client_name, const char
 {
 	const NetworkClientInfo *ci = this->GetInfo();
 
-	if (ci == NULL || StrEmpty(ci->client_name)) {
+	if (ci == nullptr || StrEmpty(ci->client_name)) {
 		seprintf(client_name, last, "Client #%4d", this->client_id);
 	} else {
 		strecpy(client_name, ci->client_name, last);
@@ -2173,12 +2173,12 @@ void NetworkPrintClients()
 
 /**
  * Perform all the server specific administration of a new company.
- * @param c  The newly created company; can't be NULL.
- * @param ci The client information of the client that made the company; can be NULL.
+ * @param c  The newly created company; can't be nullptr.
+ * @param ci The client information of the client that made the company; can be nullptr.
  */
 void NetworkServerNewCompany(const Company *c, NetworkClientInfo *ci)
 {
-	assert(c != NULL);
+	assert(c != nullptr);
 
 	if (!_network_server) return;
 
@@ -2186,18 +2186,18 @@ void NetworkServerNewCompany(const Company *c, NetworkClientInfo *ci)
 	_network_company_states[c->index].password[0] = '\0';
 	NetworkServerUpdateCompanyPassworded(c->index, false);
 
-	if (ci != NULL) {
-		/* ci is NULL when replaying, or for AIs. In neither case there is a client. */
+	if (ci != nullptr) {
+		/* ci is nullptr when replaying, or for AIs. In neither case there is a client. */
 		ci->client_playas = c->index;
 		NetworkUpdateClientInfo(ci->client_id);
-		NetworkSendCommand(0, 0, 0, CMD_RENAME_PRESIDENT, NULL, ci->client_name, c->index, 0);
+		NetworkSendCommand(0, 0, 0, CMD_RENAME_PRESIDENT, nullptr, ci->client_name, c->index, 0);
 	}
 
 	/* Announce new company on network. */
 	NetworkAdminCompanyInfo(c, true);
 
-	if (ci != NULL) {
-		/* ci is NULL when replaying, or for AIs. In neither case there is a client.
+	if (ci != nullptr) {
+		/* ci is nullptr when replaying, or for AIs. In neither case there is a client.
 		   We need to send Admin port update here so that they first know about the new company
 		   and then learn about a possibly joining client (see FS#6025) */
 		NetworkServerSendChat(NETWORK_ACTION_COMPANY_NEW, DESTTYPE_BROADCAST, 0, "", ci->client_id, c->index + 1);

src/network/network_udp.cpp

@@ -53,9 +53,9 @@ static const uint32 ADVERTISE_NORMAL_INTERVAL = 15 * 60 * 1000; ///< interval be
 static const uint32 ADVERTISE_RETRY_INTERVAL  =      10 * 1000; ///< re-advertise when no response after this many ms (10 seconds)
 static const uint32 ADVERTISE_RETRY_TIMES     =              3; ///< give up re-advertising after this much failed retries
 
-NetworkUDPSocketHandler *_udp_client_socket = NULL; ///< udp client socket
-NetworkUDPSocketHandler *_udp_server_socket = NULL; ///< udp server socket
-NetworkUDPSocketHandler *_udp_master_socket = NULL; ///< udp master socket
+NetworkUDPSocketHandler *_udp_client_socket = nullptr; ///< udp client socket
+NetworkUDPSocketHandler *_udp_server_socket = nullptr; ///< udp server socket
+NetworkUDPSocketHandler *_udp_master_socket = nullptr; ///< udp master socket
 
 static Packet PrepareUdpClientFindServerPacket()
 {
@@ -86,7 +86,7 @@ static void DoNetworkUDPQueryServer(NetworkAddress &address, bool needs_mutex, b
 	if (needs_mutex) lock.lock();
 	/* Init the packet */
 	Packet p = PrepareUdpClientFindServerPacket();
-	if (_udp_client_socket != NULL) _udp_client_socket->SendPacket(&p, &address);
+	if (_udp_client_socket != nullptr) _udp_client_socket->SendPacket(&p, &address);
 }
 
 /**
@@ -96,7 +96,7 @@ static void DoNetworkUDPQueryServer(NetworkAddress &address, bool needs_mutex, b
  */
 void NetworkUDPQueryServer(NetworkAddress address, bool manually)
 {
-	if (address.IsResolved() || !StartNewThread(NULL, "ottd:udp-query", &DoNetworkUDPQueryServer, std::move(address), true, std::move(manually))) {
+	if (address.IsResolved() || !StartNewThread(nullptr, "ottd:udp-query", &DoNetworkUDPQueryServer, std::move(address), true, std::move(manually))) {
 		DoNetworkUDPQueryServer(address, true, manually);
 	}
 }
@@ -330,7 +330,7 @@ void ServerNetworkUDPSocketHandler::Receive_CLIENT_GET_NEWGRFS(Packet *p, Networ
 			const GRFConfig *f;
 			/* Find the matching GRF file */
 			f = FindGRFConfig(info.ident.grfid, FGCM_EXACT, info.ident.md5sum);
-			if (f == NULL) continue; // The GRF is unknown to this server
+			if (f == nullptr) continue; // The GRF is unknown to this server
 
 			info.ident = f->ident;
 			info.name = f->GetName();
@@ -427,7 +427,7 @@ void ClientNetworkUDPSocketHandler::Receive_SERVER_RESPONSE_Common(Packet *p, Ne
 			in_request_count = 0;
 		};
 
-		for (c = item->info.grfconfig; c != NULL; c = c->next) {
+		for (c = item->info.grfconfig; c != nullptr; c = c->next) {
 			if (c->status == GCS_NOT_FOUND) item->info.compatible = false;
 			if (c->status != GCS_NOT_FOUND || strcmp(c->GetName(), UNKNOWN_GRF_NAME_PLACEHOLDER) != 0) continue;
 			in_request[in_request_count] = c;
@@ -516,7 +516,7 @@ void ClientNetworkUDPSocketHandler::Receive_SERVER_NEWGRFS(Packet *p, NetworkAdd
 		 * If it exists and not resolved yet, then name of the fake GRF is
 		 * overwritten with the name from the reply. */
 		GRFTextWrapper *unknown_name = FindUnknownGRFName(c.grfid, c.md5sum, false);
-		if (unknown_name != NULL && strcmp(GetGRFStringFromGRFText(unknown_name->text), UNKNOWN_GRF_NAME_PLACEHOLDER) == 0) {
+		if (unknown_name != nullptr && strcmp(GetGRFStringFromGRFText(unknown_name->text), UNKNOWN_GRF_NAME_PLACEHOLDER) == 0) {
 			AddGRFTextToList(&unknown_name->text, name);
 		}
 	}
@@ -526,7 +526,7 @@ void ClientNetworkUDPSocketHandler::HandleIncomingNetworkGameInfoGRFConfig(GRFCo
 {
 	/* Find the matching GRF file */
 	const GRFConfig *f = FindGRFConfig(config->ident.grfid, FGCM_EXACT, config->ident.md5sum);
-	if (f == NULL) {
+	if (f == nullptr) {
 		/* Don't know the GRF, so mark game incompatible and the (possibly)
 		 * already resolved name for this GRF (another server has sent the
 		 * name of the GRF already */
@@ -606,7 +606,7 @@ static void NetworkUDPRemoveAdvertiseThread()
 	p.Send_uint16(_settings_client.network.server_port);
 
 	std::lock_guard<std::mutex> lock(_network_udp_mutex);
-	if (_udp_master_socket != NULL) _udp_master_socket->SendPacket(&p, &out_addr, true);
+	if (_udp_master_socket != nullptr) _udp_master_socket->SendPacket(&p, &out_addr, true);
 }
 
 /**
@@ -618,7 +618,7 @@ void NetworkUDPRemoveAdvertise(bool blocking)
 	/* Check if we are advertising */
 	if (!_networking || !_network_server || !_network_udp_server) return;
 
-	if (blocking || !StartNewThread(NULL, "ottd:udp-advert", &NetworkUDPRemoveAdvertiseThread)) {
+	if (blocking || !StartNewThread(nullptr, "ottd:udp-advert", &NetworkUDPRemoveAdvertiseThread)) {
 		NetworkUDPRemoveAdvertiseThread();
 	}
 }
@@ -658,7 +658,7 @@ static void NetworkUDPAdvertiseThread()
 	p.Send_uint64(_session_key);
 
 	std::lock_guard<std::mutex> lock(_network_udp_mutex);
-	if (_udp_master_socket != NULL) _udp_master_socket->SendPacket(&p, &out_addr, true);
+	if (_udp_master_socket != nullptr) _udp_master_socket->SendPacket(&p, &out_addr, true);
 }
 
 /**
@@ -699,7 +699,7 @@ void NetworkUDPAdvertise()
 	if (_next_advertisement < _last_advertisement) _next_advertisement = UINT32_MAX;
 	if (_next_retry         < _last_advertisement) _next_retry         = UINT32_MAX;
 
-	if (!StartNewThread(NULL, "ottd:udp-advert", &NetworkUDPAdvertiseThread)) {
+	if (!StartNewThread(nullptr, "ottd:udp-advert", &NetworkUDPAdvertiseThread)) {
 		NetworkUDPAdvertiseThread();
 	}
 }
@@ -708,10 +708,10 @@ void NetworkUDPAdvertise()
 void NetworkUDPInitialize()
 {
 	/* If not closed, then do it. */
-	if (_udp_server_socket != NULL) NetworkUDPClose();
+	if (_udp_server_socket != nullptr) NetworkUDPClose();
 
 	DEBUG(net, 1, "[udp] initializing listeners");
-	assert(_udp_client_socket == NULL && _udp_server_socket == NULL && _udp_master_socket == NULL);
+	assert(_udp_client_socket == nullptr && _udp_server_socket == nullptr && _udp_master_socket == nullptr);
 
 	std::lock_guard<std::mutex> lock(_network_udp_mutex);
 
@@ -739,9 +739,9 @@ void NetworkUDPClose()
 	delete _udp_client_socket;
 	delete _udp_server_socket;
 	delete _udp_master_socket;
-	_udp_client_socket = NULL;
-	_udp_server_socket = NULL;
-	_udp_master_socket = NULL;
+	_udp_client_socket = nullptr;
+	_udp_server_socket = nullptr;
+	_udp_master_socket = nullptr;
 
 	_network_udp_server = false;
 	_network_udp_broadcast = 0;