(chores) cleanup some compiler warnings

* switch-cases that fall through
* potential buffer overflow in improv.cpp
* potentially uninitialized variables in FX.cpp
* potential array out-of-range on segment::col[]
* minor optimization: only apply gamma correction when result is needed
* tag some possibly unused variables with   [[maybe_unused]]

usermods/audioreactive/audio_reactive.h

@@ -176,7 +176,7 @@ static bool limiterOn = false;                 // bool: enable / disable dynamic
 #else
 static bool limiterOn = true;
 #endif
-static uint8_t micQuality = 0;   // affects input filtering; 0 normal, 1 minimal filtering, 2 no filtering
+[[maybe_unused]] static uint8_t micQuality = 0;   // input filtering; 0 normal, 1 minimal filtering, 2 no filtering - unused on 8266
 #ifdef FFT_USE_SLIDING_WINDOW
 static uint16_t attackTime = 24;              // int: attack time in milliseconds. Default 0.024sec
 static uint16_t decayTime = 250;              // int: decay time in milliseconds.  New default 250ms.

usermods/usermod_v2_rotary_encoder_ui_ALT/usermod_v2_rotary_encoder_ui_ALT.h

@@ -395,6 +395,7 @@ const char **RotaryEncoderUIUsermod::re_findModeStrings(const char json[], int n
         break;
       case ',':
         if (!insideQuotes) modeIndex++;
+         // falls through
       default:
         if (!insideQuotes) break;
     }

wled00/FX.cpp

@@ -9376,9 +9376,9 @@ uint16_t mode_particlefireworks(void) {
   // check each rocket's state and emit particles according to its state: moving up = emit exhaust, at top = explode; falling down = standby time
   uint32_t emitparticles, frequency, baseangle, hueincrement; // number of particles to emit for each rocket's state
   // variables for circular explosions
-  [[maybe_unused]] int32_t speed, currentspeed, speedvariation, percircle;
+  [[maybe_unused]] int32_t speed = 0, currentspeed, speedvariation, percircle;
   int32_t counter = 0;
-  [[maybe_unused]] uint16_t angle;
+  [[maybe_unused]] uint16_t angle = 0;
   [[maybe_unused]] unsigned angleincrement;
   bool circularexplosion = false;
 

wled00/FX.h

@@ -693,7 +693,7 @@ typedef struct Segment {
 
     uint8_t  currentMode(uint8_t modeNew);
     inline uint32_t currentColor(uint8_t slot, uint32_t colorNew) const {  // WLEDMM moved here from FX_fcn.cpp
-      return transitional && _t ? color_blend(_t->_colorT[slot], colorNew, progress(), true) : colorNew;
+      return transitional && _t ? color_blend(_t->_colorT[min(slot, uint8_t(2))], colorNew, progress(), true) : colorNew;  // WLEDMM prevent array bounds violation - only 3 color slots allowed
     }
 
     CRGBPalette16 &loadPalette(CRGBPalette16 &tgt, uint8_t pal) const;
@@ -728,25 +728,26 @@ typedef struct Segment {
 
     // WLEDMM function moved here (from FX_fcn.cpp) for better optimization by the compiler
     inline uint32_t __attribute__((hot)) color_from_palette(uint_fast16_t i, bool mapping, bool wrap, uint8_t mcol=0, uint8_t pbri = 255) const {
-      uint32_t color = gamma32(currentColor(mcol, colors[mcol]));
+      uint32_t color = currentColor(mcol, colors[min(mcol, uint8_t(2))]);     // WLEDMM prevent array bounds violation - only 3 color slots allowed
       // default palette or no RGB support on segment
       if ((palette == 0 && mcol < NUM_COLORS) || !_isRGB) {
+        color = gamma32(color);
         if (pbri == 255) return color;
-        return RGBW32(scale8_video(R(color),pbri), scale8_video(G(color),pbri), scale8_video(B(color),pbri), scale8_video(W(color),pbri));
+        else return RGBW32(scale8_video(R(color),pbri), scale8_video(G(color),pbri), scale8_video(B(color),pbri), scale8_video(W(color),pbri));
       }
       uint8_t paletteIndex = i;
       uint_fast16_t vLen = mapping ? virtualLength() : 1;
       if (mapping && vLen > 1) paletteIndex = (i*255)/(vLen -1);
       if (!wrap) paletteIndex = scale8(paletteIndex, 240); //cut off blend at palette "end"
       CRGB fastled_col = ColorFromPaletteWLED(_currentPalette, paletteIndex, pbri, (strip_getPaletteBlend() == 3)? NOBLEND:LINEARBLEND); // NOTE: paletteBlend should be global
-      uint8_t w = W(color); // extract white channel
+      uint8_t w = gamma8(W(color)); // extract white channel
       return RGBW32(fastled_col.r, fastled_col.g, fastled_col.b, w);
     }
 
     // WLEDMM function moved here (from FX_fcn.cpp) for better optimization by the compiler
     inline uint32_t color_wheel(uint8_t pos) const {
       if (palette) return color_from_palette(pos, false, true, 0);
-      uint8_t w = W(currentColor(0, colors[0])); // extract white channel
+      uint8_t w = gamma8(W(currentColor(0, colors[0]))); // extract white channel
       pos = 255 - pos;
       if (pos < 85) {
         return RGBW32((255 - pos * 3), 0, (pos * 3), w);

wled00/FX_2Dfcn.cpp

@@ -247,7 +247,7 @@ void Segment::startFrame(void) {
 void IRAM_ATTR __attribute__((hot)) Segment::setPixelColorXY_fast(int x, int y, uint32_t col, uint32_t scaled_col, int cols, int rows) const //WLEDMM
 {
   unsigned i = UINT_MAX;
-  bool sameColor = false;
+  [[maybe_unused]] bool sameColor = false;
   if (ledsrgb) { // WLEDMM small optimization
     i = x + y*cols; // avoid error checking done by XY() - be optimistic about ranges of x and y
     CRGB fastled_col = CRGB(col);
@@ -304,7 +304,7 @@ void IRAM_ATTR_YN Segment::setPixelColorXY(int x, int y, uint32_t col) //WLEDMM:
   if (x<0 || y<0 || x >= cols || y >= rows) return;  // if pixel would fall out of virtual segment just exit
 
   unsigned i = UINT_MAX;
-  bool sameColor = false;
+  [[maybe_unused]] bool sameColor = false;
   if (ledsrgb) { // WLEDMM small optimization
     i = XY(x,y);
     CRGB fastled_col = CRGB(col);
@@ -914,7 +914,7 @@ void Segment::drawText(const unsigned char* text, size_t maxLen, int16_t x, int1
   size_t textLength = min(strnlen((char*)text, maxLen), numberOfChars);
 #endif
   // pass characters to drawCharacter()
-  for (int i = 0; i < textLength; i++) {
+  for (size_t i = 0; i < textLength; i++) {
     SEGMENT.drawCharacter((unsigned char) decoded_text[i], x + w*i, y, w, h, color, col2, drawShadow);
   }
 }

wled00/FX_fcn.cpp

@@ -173,8 +173,8 @@ Segment& Segment::operator= (const Segment &orig) {
     transitional = false; // copied segment cannot be in transition
     if (name) delete[] name;
     if (_t)   delete _t;
-    CRGB* oldLeds = ledsrgb;
-    size_t oldLedsSize = ledsrgbSize;
+    // [[maybe_unused]] CRGB* oldLeds = ledsrgb;
+    // [[maybe_unused]] size_t oldLedsSize = ledsrgbSize;
     if (ledsrgb && !Segment::_globalLeds) d_free(ledsrgb);
     deallocateData();
     // copy source

wled00/FXparticleSystem.cpp

@@ -1470,7 +1470,7 @@ void ParticleSystem1D::render() {
   // add background color
   uint32_t bg_color = SEGCOLOR(1);
   if (bg_color > 0) { //if not black
-    CRGB bg_color_crgb = bg_color; // convert to CRGB
+    [[maybe_unused]] CRGB bg_color_crgb = bg_color; // convert to CRGB
     for (int32_t i = 0; i <= maxXpixel; i++) {
       #ifdef ESP8266 // no local buffer on ESP8266
       SEGMENT.addPixelColor(i, bg_color, true);

wled00/e131.cpp

@@ -13,7 +13,7 @@ static byte e131LastSequenceNumber[E131_MAX_UNIVERSE_COUNT] = {0}; // to detect
 //handles RGB data only
 void handleDDPPacket(e131_packet_t* p) {
   static bool ddpSeenPush = false;  // have we seen a push yet?
-  int lastPushSeq = e131LastSequenceNumber[0];
+  [[maybe_unused]] int lastPushSeq = e131LastSequenceNumber[0];
 
   //reject late packets belonging to previous frame (assuming 4 packets max. before push)
 #if 0  // WLEDMM fixme - we definitely have more than 5-10 packets per frame !!!
@@ -32,7 +32,7 @@ void handleDDPPacket(e131_packet_t* p) {
   uint8_t ddpChannelsPerLed = ((p->dataType & 0b00111000)>>3 == 0b011) ? 4 : 3; // data type 0x1B (formerly 0x1A) is RGBW (type 3, 8 bit/channel)
 
   // WLEDMM for debugging
-  static unsigned lastPush = millis();
+  [[maybe_unused]] static unsigned lastPush = millis();
   static unsigned packets = 0;
   static unsigned pixels = 0;
 

wled00/improv.cpp

@@ -208,8 +208,8 @@ void sendImprovInfoResponse() {
   #endif
   //Use serverDescription if it has been changed from the default "WLED", else mDNS name
   bool useMdnsName = (strcmp(serverDescription, "WLED") == 0 && strlen(cmDNS) > 0);
-  char vString[32] = { '\0' };
-  sprintf_P(vString, PSTR("%s/%i"), versionString, VERSION);
+  char vString[48] = { '\0' };
+  snprintf_P(vString, 47, PSTR("%s/%i"), versionString, VERSION);
   const char *str[4] = {"WLED", vString, bString, useMdnsName ? cmDNS : serverDescription};
 
   sendImprovRPCResult(ImprovRPCType::Request_Info, 4, str);

wled00/led.cpp

@@ -45,7 +45,7 @@ void applyValuesToSelectedSegs()
   auto pre_mode  = selsegRef.mode;
   auto pre_col0  = selsegRef.colors[0];
   auto pre_col1  = selsegRef.colors[1];
-  auto pre_col2  = selsegRef.colors[2];
+  // [[maybe_unused]] auto pre_col2  = selsegRef.colors[2];
 
   for (uint8_t i = 0; i < strip.getSegmentsNum(); i++) {
     Segment& seg = strip.getSegment(i);

wled00/util.cpp

@@ -316,11 +316,12 @@ uint8_t extractModeName(uint8_t mode, const char *src, char *dest, uint8_t maxLe
       case '"':
         insideQuotes = !insideQuotes;
         break;
-      case '[':
+      case '[': // falls through
       case ']':
         break;
       case ',':
         if (!insideQuotes) qComma++;
+         // falls through
       default:
         if (!insideQuotes || (qComma != mode)) break;
         dest[printedChars++] = singleJsonSymbol;

wled00/wled.cpp

@@ -1351,8 +1351,8 @@ void WLED::handleConnection()
     return;
   }
 
-  static unsigned retryCount1 = 0;  // WLEDMM
   static unsigned retryCount = 0;  // WLEDMM
+  [[maybe_unused]] static unsigned retryCount1 = 0;  // WLEDMM
   #ifdef ARDUINO_ARCH_ESP32
   // reconnect WiFi to clear stale allocations if heap gets too low
   if ((now - heapTime > 5000) && !strip.isUpdating()) { // WLEDMM: updated with better logic for small heap available by block, not total. // WLEDMM trying to use a moment when the strip is idle
@@ -1510,7 +1510,7 @@ void WLED::handleConnection()
 void WLED::handleStatusLED()
 {
   #if defined(STATUSLED)
-  uint32_t c = 0;
+  [[maybe_unused]] uint32_t c = 0;
 
   #if STATUSLED>=0
   if (pinManager.isPinAllocated(STATUSLED)) {

wled00/ws.cpp

@@ -290,7 +290,7 @@ static bool sendLiveLedsWs(uint32_t wsClient)  // WLEDMM added "static"
   #endif
 
   (void) unGamma8(127); // WLEDMM dummy call, just to make sure that gammaTinv is initialized, so we can use fast_unGamma8
-  uint8_t stripBrightness = strip.getBrightness();
+  // [[maybe_unused]] uint8_t stripBrightness = strip.getBrightness();
   for (size_t i = 0; pos < bufSize -2; i += n)
   {
   //WLEDMM skipping lines done right