🩹 Fix string buffer warning (MarlinFirmware#26550)

Co-authored-by: Scott Lahteine <thinkyhead@users.noreply.github.com>

Marlin/src/core/mstring.h

@@ -136,7 +136,7 @@ class MString {
   MString& setn(FSTR_P const f, int len)  { return setn_P(FTOP(f), len); }
 
   // set(repchr_t('-', 10))
-  MString& set(const repchr_t &s)         { int c = _MIN(s.count, SIZE); memset(str, s.asc, c); str[c] = '\0'; debug(F("")); return *this; }
+  MString& set(const repchr_t &s)         { int c = _MIN(s.count, SIZE); if (c >= 0) { if (c > 0) memset(str, s.asc, c); str[c] = '\0'; } debug(F("repchr_t")); return *this; }
 
   // set(spaces_t(10))
   MString& set(const spaces_t &s)         { repchr_t r(' ', s.count); return set(r); }

Marlin/src/core/types.h

@@ -309,10 +309,10 @@ typedef struct WFloat { float value; char width; char prec;
 typedef struct PFloat { float value; char prec;
                         PFloat(float v, char p) : value(v), prec(p) {}
                       } p_float_t;
-typedef struct RepChr { char asc; uint8_t count;
+typedef struct RepChr { char asc; int8_t count;
                         RepChr(char a, uint8_t c) : asc(a), count(c) {}
                       } repchr_t;
-typedef struct Spaces { uint8_t count;
+typedef struct Spaces { int8_t count;
                         Spaces(uint8_t c) : count(c) {}
                       } spaces_t;
 

Marlin/src/lcd/dogm/status_screen_DOGM.cpp

@@ -479,16 +479,16 @@ FORCE_INLINE void _draw_axis_value(const AxisEnum axis, const char *value, const
 // Prepare strings for progress display
 #if ANY(HAS_EXTRA_PROGRESS, HAS_PRINT_PROGRESS)
   static MarlinUI::progress_t progress = 0;
-  static MString<12> progressString;
+  static MString<13> progressString;
 #endif
 
 #if HAS_EXTRA_PROGRESS
 
   #if HAS_TIME_DISPLAY
     static void prepare_time_string(const duration_t &time, char prefix) {
-      char str[10];
+      char str[13];
       const uint8_t time_len = time.toDigital(str, time.value >= 60*60*24L);  // 5 to 8 chars
-      progressString.set(prefix, ':', spaces_t(10 - time_len), str);                 // 2 to 5 spaces
+      progressString.set(prefix, ':', spaces_t(10 - time_len), str);          // 2 to 5 spaces
     }
   #endif
   #if ENABLED(SHOW_PROGRESS_PERCENT)

Marlin/src/lcd/dogm/status_screen_lite_ST7920.cpp

@@ -662,39 +662,36 @@ bool ST7920_Lite_Status_Screen::indicators_changed() {
 
 // Process progress strings
 #if HAS_PRINT_PROGRESS
-  static char screenstr[8];
+  static MString<8> screenstr;
 
   #if HAS_TIME_DISPLAY
     char * ST7920_Lite_Status_Screen::prepare_time_string(const duration_t &time, char prefix) {
-      static char str[6];
-      memset(&screenstr, ' ', 8); // fill with spaces to avoid artifacts, not doing right-justification to save cycles
-      screenstr[0] = prefix;
-      TERN_(HOTENDS == 1, screenstr[1] = 0x07;)  // add bullet • separator when there is space
-      int str_length = time.toDigital(str);
-      memcpy(&screenstr[TERN(HOTENDS == 1, 2, 1)], str, str_length); //memcpy because we can't have terminator
-      return screenstr;
+      static char time_str[6];
+      (void)time.toDigital(time_str);   // Up to 5 chars
+      screenstr = prefix;
+      if (HOTENDS == 1) screenstr += char(0x07);  // Add bullet • separator when there is space
+      screenstr += time_str;
+      screenstr += Spaces(3);
+      return &screenstr;
     }
   #endif
 
   void ST7920_Lite_Status_Screen::draw_progress_string(uint8_t addr, const char *str) {
     set_ddram_address(addr);
     begin_data();
-    write_str(str, TERN(HOTENDS == 1, 8, 6));
+    write_str(str, HOTENDS == 1 ? 8 : 6);
   }
 
-  #define PPOS (DDRAM_LINE_3 + TERN(HOTENDS == 1, 4, 5)) // progress string position, in 16-bit words
+  constexpr uint8_t PPOS = (DDRAM_LINE_3 + (HOTENDS == 1 ? 4 : 5)); // Progress string position, in 16-bit words
 
   #if ENABLED(SHOW_PROGRESS_PERCENT)
     void MarlinUI::drawPercent() { lightUI.drawPercent(); }
     void ST7920_Lite_Status_Screen::drawPercent() {
-      #define LSHIFT TERN(HOTENDS == 1, 0, 1)
       const uint8_t progress = ui.get_progress_percent();
-      memset(&screenstr, ' ', 8); // fill with spaces to avoid artifacts
-      if (progress){
-        memcpy(&screenstr[2 - LSHIFT], \
-                  TERN(PRINT_PROGRESS_SHOW_DECIMALS, permyriadtostr4(ui.get_progress_permyriad()), ui8tostr3rj(progress)), \
-                  TERN(PRINT_PROGRESS_SHOW_DECIMALS, 4, 3));
-        screenstr[(TERN(PRINT_PROGRESS_SHOW_DECIMALS, 6, 5) - LSHIFT)] = '%';
+      if (progress) {
+        screenstr += Spaces(1 + (HOTENDS == 1));
+        screenstr += TERN(PRINT_PROGRESS_SHOW_DECIMALS, permyriadtostr4(ui.get_progress_permyriad()), ui8tostr3rj(progress));
+        screenstr += "%   ";
         draw_progress_string(PPOS, screenstr);
       }
     }

Marlin/src/lcd/marlinui.cpp

@@ -1035,9 +1035,13 @@ void MarlinUI::init() {
         uint8_t abs_diff = ABS(encoderDiff);
 
         #if ENCODER_PULSES_PER_STEP > 1
-          static int8_t lastEncoderDiff;
-          TERN_(HAS_TOUCH_SLEEP, if (lastEncoderDiff != encoderDiff) wakeup_screen());
-          lastEncoderDiff = encoderDiff;
+          #if HAS_TOUCH_SLEEP
+            static int8_t lastEncoderDiff;
+            if (lastEncoderDiff != encoderDiff) {
+              wakeup_screen();
+              lastEncoderDiff = encoderDiff;
+            }
+          #endif
         #endif
 
         const bool encoderPastThreshold = (abs_diff >= epps);