Clean up global variables namespace, save a few 100 bytes of flash (#5368)

* reduce scope of some variables to "static"

these are not used anywhere else. Making them static avoid name conflicts, cleans up the global scope and in some cases allows for better  optimization by the compiler.

* remove unused reference ``tz``from analog clock usermod

* side-catch: remove two "local var shadows global var" warnings

* reduce scope of functions declared globally, but not used anywhere else
Safe to make static
* declared in fcn_declare.h, only used locally in one file
* not declared in fcn_declare.h, only used locally

* HUB75 small optimization
make bit array functions "static inline"
-> better for optimization, saves some bytes because the compiler does not need to preserve a non-inline function copy for external references.

* a few more static functions
as suggested by the rabbit.

Author: softhack007

usermods/Analog_Clock/Analog_Clock.cpp

@@ -3,7 +3,6 @@
 /*
  * Usermod for analog clock
  */
-extern Timezone* tz;
 
 class AnalogClockUsermod : public Usermod {
 private:

wled00/FX.cpp

@@ -82,12 +82,12 @@
 //#define MAX_FREQ_LOG10  3.71f
 
 // effect utility functions
-uint8_t sin_gap(uint16_t in) {
+static uint8_t sin_gap(uint16_t in) {
   if (in & 0x100) return 0;
   return sin8_t(in + 192); // correct phase shift of sine so that it starts and stops at 0
 }
 
-uint16_t triwave16(uint16_t in) {
+static uint16_t triwave16(uint16_t in) {
   if (in < 0x8000) return in *2;
   return 0xFFFF - (in - 0x8000)*2;
 }
@@ -99,7 +99,7 @@ uint16_t triwave16(uint16_t in) {
  * @param attdec attack & decay, max. pulsewidth / 2
  * @returns signed waveform value
  */
-int8_t tristate_square8(uint8_t x, uint8_t pulsewidth, uint8_t attdec) {
+static int8_t tristate_square8(uint8_t x, uint8_t pulsewidth, uint8_t attdec) {
   int8_t a = 127;
   if (x > 127) {
     a = -127;

wled00/bus_manager.cpp

@@ -17,21 +17,17 @@
 #include "bus_wrapper.h"
 #include "wled.h"
 
-extern char cmDNS[];
-extern bool cctICused;
-extern bool useParallelI2S;
-
 // functions to get/set bits in an array - based on functions created by Brandon for GOL
 //  toDo : make this a class that's completely defined in a header file
 // note: these functions are automatically inline by the compiler
-bool getBitFromArray(const uint8_t* byteArray, size_t position) { // get bit value
+static inline bool getBitFromArray(const uint8_t* byteArray, size_t position) { // get bit value
   size_t byteIndex = position >> 3;    // divide by 8
   unsigned bitIndex = position & 0x07; // modulo 8
   uint8_t byteValue = byteArray[byteIndex];
   return (byteValue >> bitIndex) & 1;
 }
 
-void setBitInArray(uint8_t* byteArray, size_t position, bool value) {  // set bit - with error handling for nullptr
+static inline void setBitInArray(uint8_t* byteArray, size_t position, bool value) {  // set bit - with error handling for nullptr
     //if (byteArray == nullptr) return;
     size_t byteIndex = position >> 3;    // divide by 8
     unsigned bitIndex = position & 0x07; // modulo 8
@@ -41,11 +37,11 @@ void setBitInArray(uint8_t* byteArray, size_t position, bool value) {  // set bi
         byteArray[byteIndex] &= ~(1 << bitIndex);
 }
 
-size_t getBitArrayBytes(size_t num_bits) { // number of bytes needed for an array with num_bits bits
+static inline size_t getBitArrayBytes(size_t num_bits) { // number of bytes needed for an array with num_bits bits
   return (num_bits + 7) >> 3;
 }
 
-void setBitArray(uint8_t* byteArray, size_t numBits, bool value) {  // set all bits to same value
+static inline void setBitArray(uint8_t* byteArray, size_t numBits, bool value) {  // set all bits to same value
   if (byteArray == nullptr) return;
   size_t len =  getBitArrayBytes(numBits);
   if (value) memset(byteArray, 0xFF, len);

wled00/cfg.cpp

@@ -38,7 +38,7 @@ static constexpr bool validatePinsAndTypes(const unsigned* types, unsigned numTy
 //simple macro for ArduinoJSON's or syntax
 #define CJSON(a,b) a = b | a
 
-void getStringFromJson(char* dest, const char* src, size_t len) {
+static inline void getStringFromJson(char* dest, const char* src, size_t len) {
   if (src != nullptr) strlcpy(dest, src, len);
 }
 

wled00/e131.cpp

@@ -4,13 +4,20 @@
 #define MAX_4_CH_LEDS_PER_UNIVERSE 128
 #define MAX_CHANNELS_PER_UNIVERSE 512
 
+// forward declarations
+static void handleDDPPacket(e131_packet_t* p);
+static void handleArtnetPollReply(IPAddress ipAddress);
+static void prepareArtnetPollReply(ArtPollReply *reply);
+static void sendArtnetPollReply(ArtPollReply *reply, IPAddress ipAddress, uint16_t portAddress);
+
+
 /*
  * E1.31 handler
  */
 
 //DDP protocol support, called by handleE131Packet
 //handles RGB data only
-void handleDDPPacket(e131_packet_t* p) {
+static void handleDDPPacket(e131_packet_t* p) {
   static bool ddpSeenPush = false;  // have we seen a push yet?
   int lastPushSeq = e131LastSequenceNumber[0];
 
@@ -336,7 +343,7 @@ void handleDMXData(uint16_t uni, uint16_t dmxChannels, uint8_t* e131_data, uint8
   e131NewData = true;
 }
 
-void handleArtnetPollReply(IPAddress ipAddress) {
+static void handleArtnetPollReply(IPAddress ipAddress) {
   ArtPollReply artnetPollReply;
   prepareArtnetPollReply(&artnetPollReply);
 
@@ -402,7 +409,7 @@ void handleArtnetPollReply(IPAddress ipAddress) {
   #endif
 }
 
-void prepareArtnetPollReply(ArtPollReply *reply) {
+static void prepareArtnetPollReply(ArtPollReply *reply) {
   // Art-Net
   reply->reply_id[0] = 0x41;
   reply->reply_id[1] = 0x72;
@@ -521,7 +528,7 @@ void prepareArtnetPollReply(ArtPollReply *reply) {
   }
 }
 
-void sendArtnetPollReply(ArtPollReply *reply, IPAddress ipAddress, uint16_t portAddress) {
+static void sendArtnetPollReply(ArtPollReply *reply, IPAddress ipAddress, uint16_t portAddress) {
   reply->reply_net_sw = (uint8_t)((portAddress >> 8) & 0x007F);
   reply->reply_sub_sw = (uint8_t)((portAddress >> 4) & 0x000F);
   reply->reply_sw_out[0] = (uint8_t)(portAddress & 0x000F);

wled00/fcn_declare.h

@@ -99,9 +99,9 @@ void handleDMXInput();
 //e131.cpp
 void handleE131Packet(e131_packet_t* p, IPAddress clientIP, byte protocol);
 void handleDMXData(uint16_t uni, uint16_t dmxChannels, uint8_t* e131_data, uint8_t mde, uint8_t previousUniverses);
-void handleArtnetPollReply(IPAddress ipAddress);
-void prepareArtnetPollReply(ArtPollReply* reply);
-void sendArtnetPollReply(ArtPollReply* reply, IPAddress ipAddress, uint16_t portAddress);
+// void handleArtnetPollReply(IPAddress ipAddress);                                          // local function, only used in e131.cpp
+// void prepareArtnetPollReply(ArtPollReply* reply);                                         // local function, only used in e131.cpp
+// void sendArtnetPollReply(ArtPollReply* reply, IPAddress ipAddress, uint16_t portAddress); // local function, only used in e131.cpp
 
 //file.cpp
 bool handleFileRead(AsyncWebServerRequest*, String path);
@@ -207,8 +207,8 @@ void publishMqtt();
 //ntp.cpp
 void handleTime();
 void handleNetworkTime();
-void sendNTPPacket();
-bool checkNTPResponse();
+// void sendNTPPacket();    // local function, only used in ntp.cpp
+// bool checkNTPResponse(); // local function, only used in ntp.cpp
 void updateLocalTime();
 void getTimeString(char* out);
 bool checkCountdown();
@@ -221,8 +221,8 @@ void setTimeFromAPI(uint32_t timein);
 
 //overlay.cpp
 void handleOverlayDraw();
-void _overlayAnalogCountdown();
-void _overlayAnalogClock();
+// void _overlayAnalogCountdown();  // local function, only used in overlay.cpp
+// void _overlayAnalogClock();      // local function, only used in overlay.cpp
 
 //playlist.cpp
 void shufflePlaylist();

wled00/improv.cpp

@@ -16,8 +16,8 @@
 #endif
 
 #define IMPROV_VERSION 1
-
-void parseWiFiCommand(char *rpcData);
+// forward declarations
+static void parseWiFiCommand(char* rpcData);
 
 enum ImprovPacketType {
   Current_State = 0x01,
@@ -252,7 +252,7 @@ void startImprovWifiScan() {}
 void handleImprovWifiScan() {}
 #endif
 
-void parseWiFiCommand(char* rpcData) {
+static void parseWiFiCommand(char* rpcData) {
   unsigned len = rpcData[0];
   if (!len || len > 126) return;
 

wled00/ir.cpp

@@ -7,14 +7,14 @@
  * Infrared sensor support for several generic RGB remotes and custom JSON remote
  */
 
-IRrecv* irrecv;
-decode_results results;
-unsigned long irCheckedTime = 0;
-uint32_t lastValidCode = 0;
-byte lastRepeatableAction = ACTION_NONE;
-uint8_t lastRepeatableValue = 0;
-uint16_t irTimesRepeated = 0;
-uint8_t lastIR6ColourIdx = 0;
+static IRrecv* irrecv;
+static decode_results results;
+static unsigned long irCheckedTime = 0;
+static uint32_t lastValidCode = 0;
+static byte lastRepeatableAction = ACTION_NONE;
+static uint8_t lastRepeatableValue = 0;
+static uint16_t irTimesRepeated = 0;
+static uint8_t lastIR6ColourIdx = 0;
 
 
 // brightnessSteps: a static array of brightness levels following a geometric

wled00/json.cpp

@@ -898,7 +898,7 @@ void serializeInfo(JsonObject root)
   root["ip"] = s;
 }
 
-void setPaletteColors(JsonArray json, CRGBPalette16 palette)
+static void setPaletteColors(JsonArray json, CRGBPalette16 palette)
 {
     for (int i = 0; i < 16; i++) {
       JsonArray colors =  json.createNestedArray();
@@ -910,7 +910,7 @@ void setPaletteColors(JsonArray json, CRGBPalette16 palette)
     }
 }
 
-void setPaletteColors(JsonArray json, byte* tcp)
+static void setPaletteColors(JsonArray json, byte* tcp)
 {
     TRGBGradientPaletteEntryUnion* ent = (TRGBGradientPaletteEntryUnion*)(tcp);
     TRGBGradientPaletteEntryUnion u;

wled00/ntp.cpp

@@ -2,6 +2,11 @@
 #include "wled.h"
 #include "fcn_declare.h"
 
+// forward declarations
+static void sendNTPPacket();
+static bool checkNTPResponse();
+
+
 // WARNING: may cause errors in sunset calculations on ESP8266, see #3400
 // building with `-D WLED_USE_REAL_MATH` will prevent those errors at the expense of flash and RAM
 
@@ -11,7 +16,7 @@
 //#define WLED_DEBUG_NTP
 #define NTP_SYNC_INTERVAL 42000UL //Get fresh NTP time about twice per day
 
-Timezone* tz;
+static Timezone* tz;
 
 #define TZ_UTC                  0
 #define TZ_UK                   1
@@ -42,7 +47,7 @@ Timezone* tz;
 #define TZ_COUNT               25
 #define TZ_INIT               255
 
-byte tzCurrent = TZ_INIT; //uninitialized
+static byte tzCurrent = TZ_INIT; //uninitialized
 
 /* C++11 form -- static std::array<std::pair<TimeChangeRule, TimeChangeRule>, TZ_COUNT> TZ_TABLE PROGMEM = {{ */
 static const std::pair<TimeChangeRule, TimeChangeRule> TZ_TABLE[] PROGMEM = {
@@ -199,7 +204,7 @@ void handleNetworkTime()
   }
 }
 
-void sendNTPPacket()
+static void sendNTPPacket()
 {
   if (!ntpServerIP.fromString(ntpServerName)) //see if server is IP or domain
   {
@@ -245,7 +250,7 @@ static bool isValidNtpResponse(const byte* ntpPacket) {
   return true;
 }
 
-bool checkNTPResponse()
+static bool checkNTPResponse()
 {
   int cb = ntpUdp.parsePacket();
   if (cb < NTP_MIN_PACKET_SIZE) {