added ArduinoWiFiServer with send-to-all-clients functionality (#7612)

and with available() working according to Arduino documentation
plus PagerServer example

libraries/ESP8266WiFi/src/ArduinoWiFiServer.h

@@ -0,0 +1,135 @@
+/*
+  ArduinoWiFiServer.h - Arduino compatible WiFiServer
+  implementation for ESP8266Wifi library.
+  Copyright (c) 2020 Juraj Andrassy
+
+  This library is free software; you can redistribute it and/or
+  modify it under the terms of the GNU Lesser General Public
+  License as published by the Free Software Foundation; either
+  version 2.1 of the License, or (at your option) any later version.
+
+  This library is distributed in the hope that it will be useful,
+  but WITHOUT ANY WARRANTY; without even the implied warranty of
+  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+  Lesser General Public License for more details.
+
+  You should have received a copy of the GNU Lesser General Public
+  License along with this library; if not, write to the Free Software
+  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+*/
+
+#ifndef arduinowifiserver_h
+#define arduinowifiserver_h
+
+#include <ESP8266WiFi.h>
+
+#ifndef MAX_MONITORED_CLIENTS
+#define MAX_MONITORED_CLIENTS 5
+#endif
+
+template <class TServer, class TClient>
+class ArduinoComptibleWiFiServerTemplate : public TServer {
+public:
+
+  ArduinoComptibleWiFiServerTemplate(const IPAddress& addr, uint16_t port) : TServer(addr, port) {}
+  ArduinoComptibleWiFiServerTemplate(uint16_t port) : TServer(port) {}
+  virtual ~ArduinoComptibleWiFiServerTemplate() {}
+
+  // https://www.arduino.cc/en/Reference/EthernetServerAccept
+  TClient accept() {
+    return TServer::available();
+  }
+
+  // https://www.arduino.cc/en/Reference/WiFiServerAvailable
+  TClient available() {
+
+    // update connected clients
+    for (uint8_t i = 0; i < MAX_MONITORED_CLIENTS; i++) {
+      if (!connectedClients[i]) {
+        connectedClients[i] = accept();
+      }
+    }
+    // find next client with data available
+    for (uint8_t i = 0; i < MAX_MONITORED_CLIENTS; i++) {
+      if (index == MAX_MONITORED_CLIENTS) {
+        index = 0;
+      }
+      TClient& client = connectedClients[index];
+      index++;
+      if (client.available())
+        return client;
+    }
+    return TClient(); // no client with data found
+  }
+
+  virtual size_t write(uint8_t b) override {
+    return write(&b, 1);
+  }
+
+  virtual size_t write(const uint8_t *buf, size_t size) override {
+    if (size == 0)
+      return 0;
+    size_t ret = 0;
+    size_t a = size;
+    while (true) {
+      for (uint8_t i = 0; i < MAX_MONITORED_CLIENTS; i++) {
+        WiFiClient& client = connectedClients[i];
+        if (client.status() == ESTABLISHED && client.availableForWrite() < (int) a) {
+          a = client.availableForWrite();
+        }
+      }
+      if (a == 0)
+        break;
+      for (uint8_t i = 0; i < MAX_MONITORED_CLIENTS; i++) {
+        if (connectedClients[i].status() == ESTABLISHED) {
+          connectedClients[i].write(buf, a);
+        }
+      }
+      ret += a;
+      if (ret == size)
+        break;
+      buf += a;
+      a = size - ret;
+    }
+    return ret;
+  }
+
+  using Print::write;
+
+  virtual void flush() override {
+    flush(0);
+  }
+
+  virtual void flush(unsigned int maxWaitMs) {
+    for (uint8_t i = 0; i < MAX_MONITORED_CLIENTS; i++) {
+      if (connectedClients[i].status() == ESTABLISHED) {
+        connectedClients[i].flush(maxWaitMs);
+      }
+    }
+  }
+
+  operator bool() {
+    return (TServer::status() == LISTEN);
+  }
+
+  void close() {
+    TServer::stop();
+    for (uint8_t i = 0; i < MAX_MONITORED_CLIENTS; i++) {
+      if (connectedClients[i]) {
+        connectedClients[i].stop();
+      }
+    }
+  }
+  void stop() {close();}
+  void end() {close();}
+
+private:
+  TClient connectedClients[MAX_MONITORED_CLIENTS];
+  uint8_t index = 0;
+
+};
+
+typedef ArduinoComptibleWiFiServerTemplate<WiFiServer, WiFiClient> ArduinoWiFiServer;
+typedef ArduinoComptibleWiFiServerTemplate<WiFiServerSecure, WiFiClientSecure> ArduinoWiFiServerSecure;
+
+#endif