json output via udp

PString.h

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+/*
+  PString.h - Lightweight printable string class
+  Copyright (c) 2009-2012 Mikal Hart.  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
+*/
+
+#ifndef PString_h
+#define PString_h
+
+#include "Print.h"
+#include <stdarg.h>
+#include <stddef.h>
+#include <stdio.h>
+#include <string.h>
+
+#define PSTRING_LIBRARY_VERSION 3
+
+class PString : public Print
+{
+private:
+  char *_buf, *_cur;
+  size_t _size;
+public:
+#if defined(ARDUINO) && ARDUINO >= 100
+	virtual size_t write(uint8_t);
+#else
+	virtual void write(uint8_t);
+#endif
+
+public:
+
+  // Basic constructor requires a preallocated buffer
+  PString(char *buf, size_t size) : _buf(buf), _size(size)
+  { begin(); }
+
+  // templated constructors allow inline renderings of this type: PString(buf, size, myfloat[, modifier]);
+  template<class T> PString(char *buf, size_t size, T arg) : _buf(buf), _size(size) 
+  { begin(); print(arg); }
+  
+  template<class T> PString(char *buf, size_t size, T arg, int modifier) : _buf(buf), _size(size) 
+  { begin(); print(arg, modifier); }
+
+  // returns the length of the current string, not counting the 0 terminator
+  inline const size_t length() 
+  { return _cur - _buf; }
+
+  // returns the capacity of the string
+  inline const size_t capacity() 
+  { return _size; }
+
+  // gives access to the internal string
+  inline operator const char *() 
+  { return _buf; }
+
+  // compare to another string
+  bool operator==(const char *str) 
+  { return _size > 0 && !strcmp(_buf, str); }
+
+  // call this to re-use an existing string
+  void begin();
+
+  // This function allows assignment to an arbitrary scalar value like str = myfloat;
+  template<class T> inline PString &operator =(T arg) 
+  { begin(); print(arg); return *this; }
+
+  // Concatenation str += myfloat;
+  template<class T> inline PString &operator +=(T arg) 
+  { print(arg); return *this; }
+
+  // Safe access to sprintf-like formatting, e.g. str.format("Hi, my name is %s and I'm %d years old", name, age);
+  int format(char *str, ...);
+};
+
+#endif