Convert config code to a static class

Marlin/Marlin_main.cpp

         endstop_adj[ABC] = { 0 };
 
   // These values are loaded or reset at boot time when setup() calls
-  // Config_RetrieveSettings(), which calls recalc_delta_settings().
+  // settings.load(), which calls recalc_delta_settings().
   float delta_radius,
         delta_tower_angle_trim[ABC],
         delta_tower[ABC][2],
  * M500: Store settings in EEPROM
  */
 inline void gcode_M500() {
-  (void)Config_StoreSettings();
+  (void)settings.save();
 }
 
 /**
  * M501: Read settings from EEPROM
  */
 inline void gcode_M501() {
-  (void)Config_RetrieveSettings();
+  (void)settings.load();
 }
 
 /**
  * M502: Revert to default settings
  */
 inline void gcode_M502() {
-  (void)Config_ResetDefault();
+  (void)settings.reset();
 }
 
 /**
  * M503: print settings currently in memory
  */
 inline void gcode_M503() {
-  (void)Config_PrintSettings(code_seen('S') && !code_value_bool());
+  (void)settings.report(code_seen('S') && !code_value_bool());
 }
 
 #if ENABLED(ABORT_ON_ENDSTOP_HIT_FEATURE_ENABLED)
 
   // Load data from EEPROM if available (or use defaults)
   // This also updates variables in the planner, elsewhere
-  (void)Config_RetrieveSettings();
+  (void)settings.load();
 
   #if DISABLED(NO_WORKSPACE_OFFSETS)
     // Initialize current position based on home_offset

Marlin/configuration_store.cpp

 /**
  * configuration_store.cpp
  *
- * Configuration and EEPROM storage
+ * Settings and EEPROM storage
  *
  * IMPORTANT:  Whenever there are changes made to the variables stored in EEPROM
  * in the functions below, also increment the version number. This makes sure that
  *  580                                Minimum end-point
  * 1901 (580 + 36 + 9 + 288 + 988)     Maximum end-point
  */
+#include "configuration_store.h"
+
+MarlinSettings settings;
+
 #include "Marlin.h"
 #include "language.h"
 #include "endstops.h"
 #include "planner.h"
 #include "temperature.h"
 #include "ultralcd.h"
-#include "configuration_store.h"
 
 #if ENABLED(MESH_BED_LEVELING)
   #include "mesh_bed_leveling.h"
 /**
  * Post-process after Retrieve or Reset
  */
-void Config_Postprocess() {
+void MarlinSettings::postprocess() {
   // steps per s2 needs to be updated to agree with units per s2
   planner.reset_acceleration_rates();
 
 
 #if ENABLED(EEPROM_SETTINGS)
 
-  uint16_t eeprom_checksum;
   const char version[4] = EEPROM_VERSION;
 
-  bool eeprom_write_error;
+  uint16_t MarlinSettings::eeprom_checksum;
+
+  bool MarlinSettings::eeprom_write_error,
+       MarlinSettings::eeprom_read_error;
 
-  void _EEPROM_writeData(int &pos, const uint8_t* value, uint16_t size) {
+  void MarlinSettings::write_data(int &pos, const uint8_t* value, uint16_t size) {
     if (eeprom_write_error) return;
     while (size--) {
       uint8_t * const p = (uint8_t * const)pos;
       value++;
     };
   }
-  bool eeprom_read_error;
-  void _EEPROM_readData(int &pos, uint8_t* value, uint16_t size) {
+  void MarlinSettings::read_data(int &pos, uint8_t* value, uint16_t size) {
     do {
       uint8_t c = eeprom_read_byte((unsigned char*)pos);
       if (!eeprom_read_error) *value = c;
   #define DUMMY_PID_VALUE 3000.0f
   #define EEPROM_START() int eeprom_index = EEPROM_OFFSET
   #define EEPROM_SKIP(VAR) eeprom_index += sizeof(VAR)
-  #define EEPROM_WRITE(VAR) _EEPROM_writeData(eeprom_index, (uint8_t*)&VAR, sizeof(VAR))
-  #define EEPROM_READ(VAR) _EEPROM_readData(eeprom_index, (uint8_t*)&VAR, sizeof(VAR))
-  #define EEPROM_ASSERT(TST,ERR) if () do{ SERIAL_ERROR_START; SERIAL_ERRORLNPGM(ERR); eeprom_read_error |= true; }while(0)
+  #define EEPROM_WRITE(VAR) write_data(eeprom_index, (uint8_t*)&VAR, sizeof(VAR))
+  #define EEPROM_READ(VAR) read_data(eeprom_index, (uint8_t*)&VAR, sizeof(VAR))
+  #define EEPROM_ASSERT(TST,ERR) if (!(TST)) do{ SERIAL_ERROR_START; SERIAL_ERRORLNPGM(ERR); eeprom_read_error = true; }while(0)
 
   /**
    * M500 - Store Configuration
    */
-  bool Config_StoreSettings() {
+  bool MarlinSettings::save() {
     float dummy = 0.0f;
     char ver[4] = "000";
 
   /**
    * M501 - Retrieve Configuration
    */
-  bool Config_RetrieveSettings() {
+  bool MarlinSettings::load() {
 
     EEPROM_START();
     eeprom_read_error = false; // If set EEPROM_READ won't write into RAM
       SERIAL_ECHOPGM("EEPROM version mismatch ");
       SERIAL_ECHOPAIR("(EEPROM=", stored_ver);
       SERIAL_ECHOLNPGM(" Marlin=" EEPROM_VERSION ")");
-      Config_ResetDefault();
+      reset();
     }
     else {
       float dummy = 0;
       EEPROM_READ(lcd_preheat_bed_temp);
       EEPROM_READ(lcd_preheat_fan_speed);
 
+      //EEPROM_ASSERT(
+      //  WITHIN(lcd_preheat_fan_speed, 0, 255),
+      //  "lcd_preheat_fan_speed out of range"
+      //);
+
       #if ENABLED(PIDTEMP)
         for (uint8_t e = 0; e < MAX_EXTRUDERS; e++) {
           EEPROM_READ(dummy); // Kp
 
       if (eeprom_checksum == stored_checksum) {
         if (eeprom_read_error)
-          Config_ResetDefault();
+          reset();
         else {
-          Config_Postprocess();
+          postprocess();
           SERIAL_ECHO_START;
           SERIAL_ECHO(version);
           SERIAL_ECHOPAIR(" stored settings retrieved (", eeprom_index - (EEPROM_OFFSET));
       else {
         SERIAL_ERROR_START;
         SERIAL_ERRORLNPGM("EEPROM checksum mismatch");
-        Config_ResetDefault();
+        reset();
       }
 
       #if ENABLED(AUTO_BED_LEVELING_UBL)
       #endif
     }
     #if ENABLED(EEPROM_CHITCHAT)
-      Config_PrintSettings();
+      report();
     #endif
 
     return !eeprom_read_error;
 
 #else // !EEPROM_SETTINGS
 
-  bool Config_StoreSettings() {
+  bool MarlinSettings::save() {
     SERIAL_ERROR_START;
     SERIAL_ERRORLNPGM("EEPROM disabled");
     return false;
 /**
  * M502 - Reset Configuration
  */
-void Config_ResetDefault() {
+void MarlinSettings::reset() {
   const float tmp1[] = DEFAULT_AXIS_STEPS_PER_UNIT, tmp2[] = DEFAULT_MAX_FEEDRATE;
   const uint32_t tmp3[] = DEFAULT_MAX_ACCELERATION;
   LOOP_XYZE_N(i) {
     #endif
   #endif
 
-  Config_Postprocess();
+  postprocess();
 
   SERIAL_ECHO_START;
   SERIAL_ECHOLNPGM("Hardcoded Default Settings Loaded");
   #define CONFIG_ECHO_START do{ if (!forReplay) SERIAL_ECHO_START; }while(0)
 
   /**
-   * M503 - Print Configuration
+   * M503 - Report current settings in RAM
+   *   
+   * Unless specifically disabled, M503 is available even without EEPROM
    */
-  void Config_PrintSettings(bool forReplay) {
-    // Always have this function, even with EEPROM_SETTINGS disabled, the current values will be shown
+  void MarlinSettings::report(bool forReplay) {
 
     CONFIG_ECHO_START;
 

Marlin/configuration_store.h

 
 #include "MarlinConfig.h"
 
-void Config_ResetDefault();
-bool Config_StoreSettings();
-
-#if DISABLED(DISABLE_M503)
-  void Config_PrintSettings(bool forReplay=false);
-#else
-  FORCE_INLINE void Config_PrintSettings(bool forReplay=false) {}
-#endif
-
-#if ENABLED(EEPROM_SETTINGS)
-  bool Config_RetrieveSettings();
-#else
-  FORCE_INLINE bool Config_RetrieveSettings() { Config_ResetDefault(); Config_PrintSettings(); return true; }
-#endif
-
-#endif //CONFIGURATION_STORE_H
+class MarlinSettings {
+  public:
+    MarlinSettings() { }
+
+    static void reset();
+    static bool save();
+
+    #if ENABLED(EEPROM_SETTINGS)
+      static bool load();
+    #else
+      FORCE_INLINE
+      static bool load() { reset(); report(); return true; }
+    #endif
+
+    #if DISABLED(DISABLE_M503)
+      static void report(bool forReplay=false);
+    #else
+      FORCE_INLINE
+      static void report(bool forReplay=false) { }
+    #endif
+
+  private:
+    static void postprocess();
+
+    #if ENABLED(EEPROM_SETTINGS)
+      static uint16_t eeprom_checksum;
+      static bool eeprom_read_error, eeprom_write_error;
+      static void write_data(int &pos, const uint8_t* value, uint16_t size);
+      static void read_data(int &pos, uint8_t* value, uint16_t size);
+    #endif
+};
+
+extern MarlinSettings settings;
+
+#endif // CONFIGURATION_STORE_H

Marlin/ultralcd.cpp

    */
 
   #if ENABLED(EEPROM_SETTINGS)
-    static void lcd_store_settings()   { lcd_completion_feedback(Config_StoreSettings()); }
-    static void lcd_load_settings()    { lcd_completion_feedback(Config_RetrieveSettings()); }
+    static void lcd_store_settings()   { lcd_completion_feedback(settings.save()); }
+    static void lcd_load_settings()    { lcd_completion_feedback(settings.load()); }
   #endif
 
   static void lcd_factory_settings() {
-    Config_ResetDefault();
+    settings.reset();
     lcd_completion_feedback();
   }