extended debug facilities for output

* Output strings with unprintable characters either as a table or as
continuing string of characters; the byte value of unprintable
characters (`isprint(<character>, <locale>) == false`) is shown.
* Output readable string of `key` -> `value` pairs with an enumerated
type for the key and union type for the value.

Debug.cpp

@@ -22,7 +22,13 @@
 
 namespace krikkel
 {
+    using std::string;
+    using std::fstream;
     using std::filesystem::is_directory;
+    using std::endl;
+    using std::time;
+    using std::localtime;
+    using std::strftime;
 
     Debug::Debug()
     {
@@ -30,7 +36,7 @@ namespace krikkel
         if(is_directory("sandbox"))
             directory = "./sandbox";
         logFile = fstream(directory + "/debug.log", fstream::out | fstream::app);//| fstream::trunc);
-        logFile << endl << endl << "New instance of class Debug." << endl;
+        logFile << endl << endl << endl << endl << "New instance of class Debug." << endl;
         logFile << getUname();
         logFile.flush();
     }
@@ -50,7 +56,7 @@ namespace krikkel
 
     string Debug::getTimestamp()
     {
-        time_t now = std::time(NULL);
+        time_t now = time(NULL);
         tm *localNow = localtime(&now);
         static char formattedLocalNow[32];
         strftime(formattedLocalNow, 32, "%c", localNow);

Debug.hpp

@@ -1,6 +1,7 @@
 /**
  * @brief Writes messages to `debug.log` if `NDEBUG` is not defined.
  * @author Christian Burger (christian@krikkel.de)
+ * @todo refactor macros
  */
 
 #ifndef __DEBUG_H__
@@ -11,30 +12,24 @@
 #include <fstream>
 #include <string>
 #include <ctime>
+#include <locale>
 
 namespace krikkel
 {
-    using std::fstream;
-    using std::string;
-    using std::endl;
-    using std::strftime;
-    using std::localtime;
-    using std::time;
-
     class Debug
     {
         private:
-            fstream logFile;
+            std::fstream logFile;
             static const int MAX_NUMBER_OF_SYSCALLS = 1024;
             static const char * syscalls[MAX_NUMBER_OF_SYSCALLS];
 
             Debug();
-            string getTimestamp();
-            string getUname();
+            std::string getTimestamp();
+            std::string getUname();
 
         public:
-            void log(string message, string fileName, int lineNo
-                   , string functionName);
+            void log(std::string message, std::string fileName, int lineNo
+                   , std::string functionName);
             static Debug *getInstance();
     };
 }
@@ -42,10 +37,84 @@ namespace krikkel
 #define __debug_log(message) krikkel::Debug::getInstance()\
                                     ->log(message, __FILE__, __LINE__, __func__)
 
+
+/// @todo need an explanation on why and how to use this
+///       this is the complete opposite of self-explanatory
+#define __debug_stringify_switch_begin(closureName, __prop, __value) \
+    auto __debug_stringify__##closureName = [__prop, __value]() -> std::string \
+    { \
+        std::string propertyName, valueString; \
+        switch(__prop) \
+        {
+#define __debug_stringify_switch_case(caseTestValue) \
+            case caseTestValue: \
+                propertyName = (propertyName.empty() ? #caseTestValue : propertyName)
+#define __debug_stringify_switch_case_end_bool(value) \
+                valueString = (value ? "true" : "false"); \
+                break
+#define __debug_stringify_switch_case_end_string(value) \
+                valueString = "\"" + std::string(value) + "\""; \
+                break
+#define __debug_stringify_switch_case_end_number(value) \
+                valueString = std::to_string(value); \
+                break;
+#define __debug_stringify_switch_end(__prop) \
+            default: \
+                propertyName = "default case triggerd for " + std::to_string(__prop); \
+                break; \
+        } \
+        return propertyName + " = " + valueString; \
+    }
+#define __debug_stringify_get_string(closureName) __debug_stringify__##closureName()
+
+#define __debug_bytes_printable_table(unprintable, numberOfBytes) ([](const char *bytes, size_t length) \
+    { \
+        std::locale loc; \
+        size_t index, targetIndex = 0; \
+        size_t targetLength = (length / 16 + 1) * (3 + 3 * 16 + 1) + 1; \
+        char targetBytes[targetLength]; \
+        for(index = 0; index < length; index++) \
+        { \
+            if(std::isprint(bytes[index], loc)) \
+                targetIndex += snprintf(targetBytes + targetIndex, targetLength - targetIndex, index % 16 == 0 ? " |   %c" : "  %c", bytes[index]); \
+            else \
+                targetIndex += snprintf(targetBytes + targetIndex, targetLength - targetIndex, index % 16 == 0 ? " |  %02x" : " %02x", bytes[index]); \
+            if(index % 16 == 15) \
+                targetIndex += snprintf(targetBytes + targetIndex, targetLength - targetIndex, "\n"); \
+        } \
+        if(index % 16) \
+            snprintf(targetBytes + targetIndex, targetLength - targetIndex, "\n"); \
+        return std::string(targetBytes); \
+    } \
+    )(unprintable, numberOfBytes)
+
+#define __debug_bytes_printable(bytes, length) ([](std::string unprintable, size_t numberOfBytes) -> std::string \
+    { \
+        std::locale loc; \
+        std::string result; \
+        for(char character : unprintable) \
+        { \
+            if(!numberOfBytes--) \
+                break; \
+            if(std::isprint(character, loc) && character != '<') \
+                result += character; \
+            else \
+                result += "<" + std::to_string(character) + ">"; \
+        } \
+        return result; \
+    })(bytes, length)
+
 #else
 
 /// @todo check what's the business with this "((void)0)" instead of empty macro
 #define __debug_log(message)
+#define __debug_stringify_switch_begin(closureName, __prop, __value)
+#define __debug_stringify_switch_case(caseTestValue)
+#define __debug_stringify_switch_case_end_bool(value)
+#define __debug_stringify_switch_case_end_string(value)
+#define __debug_stringify_switch_case_end_number(value)
+#define __debug_stringify_switch_end()
+#define __debug_bytes_printable(bytes)
 
 #endif /* NDEBUG */