Add IPAddress class

teensy4/IPAddress.cpp

+/*
+  IPAddress.cpp - Base class that provides IPAddress
+  Copyright (c) 2011 Adrian McEwen.  All right reserved.
+
+  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
+*/
+
+#include <Arduino.h>
+#include "IPAddress.h"
+
+size_t IPAddress::printTo(Print& p) const
+{
+	int i=0;
+	while (1) {
+		p.print(_address.bytes[i], DEC);
+		if (++i >= 4) return 4;
+		p.write('.');
+	}
+}
+
+bool IPAddress::fromString(const char *address)
+{
+	unsigned int acc = 0; // Accumulator
+	unsigned int dots = 0;
+
+	while (*address) {
+		char c = *address++;
+		if (c >= '0' && c <= '9') {
+			acc = acc * 10 + (c - '0');
+			if (acc > 255) {
+				// Value out of [0..255] range
+				return false;
+			}
+		} else if (c == '.') {
+			if (dots == 3) {
+				// Too much dots (there must be 3 dots)
+				return false;
+			}
+			_address.bytes[dots++] = acc;
+			acc = 0;
+		} else {
+			// Invalid char
+			return false;
+		}
+	}
+	if (dots != 3) {
+		// Too few dots (there must be 3 dots)
+		return false;
+	}
+	_address.bytes[3] = acc;
+	return true;
+}
+