added StringLogger

DIAG.h

@@ -20,6 +20,10 @@
 #define DIAG_h
 
 #include "StringFormatter.h"
-#define DIAG  StringFormatter::diag
+#include "StringLogger.h"
+
+// #define DIAG  StringFormatter::diag
+#define DIAG  StringLogger::get().diag  // allows to add other log writers 
 #define LCD   StringFormatter::lcd
+
 #endif

StringLogger.cpp

@@ -0,0 +1,44 @@
+#include "StringLogger.h"
+
+// DIAG.h the #define DIAG points to here ... 
+// EthernetSetup , Wifisetup, etc can register a function to be called allowing the channel
+// to publish the diag info to 
+// serial is default end enabled all the time
+
+StringLogger StringLogger::singleton;          // static instantiation;
+
+void StringLogger::addDiagWriter(DiagWriter l) {
+    if ( registered == MAXWRITERS ) {
+        Serial.println("Error: Max amount of writers exceeded.");
+        return;
+    }
+    writers[registered] = l;
+    registered++;
+}
+
+
+void StringLogger::diag(const FSH *input,...)
+{ 
+
+    char b1[128];
+
+    va_list args;
+    va_start(args, input);
+
+    int len = 0;
+    len += sprintf(&b1[len], "<* ");
+    len += vsprintf_P(&b1[len], (const char *)input, args); 
+    len += sprintf(&b1[len], " *>\n");
+
+    // allways print to Serial 
+    Serial.print(b1);
+
+    // callback the other registered diag writers 
+    for (size_t i = 0; i < (size_t) registered; i++)
+    {
+        writers[i](b1, len);   
+    }
+
+    va_end(args);
+
+}

StringLogger.h

@@ -0,0 +1,45 @@
+#ifndef StringLogger_h
+#define StringLogger_h
+
+#include "MemStream.h"
+#include "RingStream.h"
+#include "StringFormatter.h"
+#include <stdarg.h>
+
+// stream for diagnostics in addition to serial you should be able to configure
+// additional (besides Serial) 'outputs' to e.g. Ethernet or MQTT or WIFI etc ...
+// Serial outpout is managed in StringFormatter on top for formatting the message
+// which gets printed char by char
+
+#define MAXWRITERS 10
+
+typedef void (*DiagWriter)(const char *msg, const int length);
+
+class StringLogger
+{
+
+private:
+    // Methods
+    StringLogger() = default;
+    StringLogger(const StringLogger &);            // non construction-copyable
+    StringLogger &operator=(const StringLogger &); // non copyable
+
+    // Members
+    static StringLogger singleton; // unique instance of the MQTTInterface object
+    DiagWriter writers[MAXWRITERS];
+    int registered = 0; // number of registered writers ( Serial is not counted as always used )
+
+public:
+    // Methods
+    static StringLogger &get() noexcept
+    { // return a reference to the unique instance
+        return singleton;
+    }
+    void diag(const FSH *input...);
+    void addDiagWriter(DiagWriter l);
+    ~StringLogger() = default;
+
+    // Members
+};
+
+#endif