Remove ArduinoJSON processing of gapfile (do not use global JSON buffer).

- see wled#5518

Author: blazoncek

wled00/FX_2Dfcn.cpp

@@ -63,6 +63,7 @@ void WS2812FX::setUpMatrix() {
       unsigned matrixSize = Segment::maxWidth * Segment::maxHeight; // less or equal to getLengthTotal()
       for (unsigned i = 0; i < matrixSize; i++) customMappingTable[i] = 0xFFFFU;
       for (unsigned i = matrixSize; i < customMappingSize; i++) customMappingTable[i] = i; // trailing LEDs for ledmap (after matrix) if it exist
+
       // we will try to load a "gap" array (a JSON file)
       // the array has to have the same amount of values as mapping array (or larger)
       // "gap" array is used while building ledmap (mapping array)
@@ -75,6 +76,43 @@ void WS2812FX::setUpMatrix() {
       size_t  gapSize = 0;
       int8_t *gapTable = nullptr;
 
+      if (isFile) {
+        DEBUG_PRINTLN(F("Loading gaps."));
+        File f = WLED_FS.open(fileName, "r");
+        if (f && f.find("[")) {
+          size_t pos = f.position();
+          // count elements first to know how much to allocate
+          char token[32]; strcpy_P(token, PSTR(" \n\r\t,-01"));
+          //while (f.available()) if (f.read() == ',') gapSize++;
+          while (f.available()) {
+            char c = f.read();
+            if (strchr(token, c) == nullptr) break; // invalid character, stop
+            if (c == ',') gapSize++;
+          }
+          gapSize++;  // there's one more entry than there is commas
+          if (gapSize >= matrixSize) {
+            f.seek(pos);
+            gapTable = static_cast<int8_t*>(p_malloc(gapSize));
+            if (gapTable) {
+              memset(gapTable, 1, gapSize);
+              pos = 0;
+              while (f.available() && pos < gapSize) {
+                size_t n = f.readBytesUntil(',', token, sizeof(token)-1);
+                token[n] = '\0';
+                if (n < sizeof(token)-1) gapTable[pos++] = (int8_t)constrain(strtol(token, nullptr, 10), -1, 1);
+                if (strchr(token, ']') != nullptr) break; // end of array
+              }
+              DEBUG_PRINTLN(F("Gaps loaded."));
+            } else {
+              DEBUG_PRINTLN(F("Out of memory."));
+            }
+          } else {
+            DEBUG_PRINTLN(F("Gapfile too small."));
+          }
+          f.close();
+        }
+      }
+/*
       if (isFile && requestJSONBufferLock(20)) {
         DEBUG_PRINT(F("Reading LED gap from "));
         DEBUG_PRINTLN(fileName);
@@ -96,7 +134,7 @@ void WS2812FX::setUpMatrix() {
         DEBUG_PRINTLN(F("Gaps loaded."));
         releaseJSONBufferLock();
       }
-
+*/
       unsigned x, y, pix=0; //pixel
       for (const Panel &p : panel) {
         unsigned h = p.vertical ? p.height : p.width;