added example ETL sketch (Embedded Template Library)

examples/Circular_Buffer/Circular_Buffer.ino

@@ -0,0 +1,103 @@
+// Please format this file with clang before check-in to GitHub
+/*
+  Circular Buffer using ETL (embedded template library)
+
+  ETL by John Wellbelove, https://www.etlcpp.com/circular_buffer.html
+ */
+
+// ensure no STL
+#define ETL_NO_STL
+
+#include <TimeLib.h>                     // time_t=seconds since Jan 1, 1970, https://github.com/PaulStoffregen/Time
+#include "Embedded_Template_Library.h"   // Required for any etl import using Arduino IDE
+#include "etl/circular_buffer.h"         // Embedded Template Library
+
+// ========== struct for each item in the buffer
+struct satCountItem {
+  time_t tm;  // seconds since Jan 1, 1970
+  int numSats;
+};
+
+etl::circular_buffer<int, 12> cb;              // dummy, unused
+etl::circular_buffer<int, 12>::iterator itr;   // dummy, unused
+
+etl::circular_buffer<satCountItem, 12> cbSats;
+etl::circular_buffer<satCountItem, 12>::iterator cbIter;
+
+// ========== helpers
+// pushes a value to the back of the circular buffer
+void mypush(time_t tm, int nSats) {
+  satCountItem item = {tm, nSats};
+  cbSats.push(item);
+}
+
+// output one element of data
+// slot = which bar of the bar graph, 0..12
+// value = number of satellites in view
+  void showBar(int slot, satCountItem item) {
+    char msg[128];
+    int hh = hour(item.tm);
+    int mm = minute(item.tm);
+    int ss = second(item.tm);
+    snprintf(msg, sizeof(msg), "[%d] %02d:%02d:%02d time, %d satellites", 
+                               slot, hh, mm, ss, item.numSats);
+    Serial.println(msg);
+  }
+
+// the setup routine runs once when you press reset:
+void setup() {
+  // ----- init serial monitor
+  Serial.begin(115200);   // init for debugging in the Arduino IDE
+  while (!Serial) {       // Wait for console in the Arduino IDE
+    yield();
+  }
+  Serial.println("========== Test 1: Print empty buffer");
+  // print all elements
+  int ii = 0;
+  for (cbIter=cbSats.begin(); cbIter<cbSats.end(); ++cbIter) {
+    showBar(ii, *cbIter);
+    ii++;
+  }
+
+  Serial.println("========== Test 2: Print buffer with one element");
+  // populate the circular buffer
+  //      hh mm ss day mo yr
+  setTime( 2, 0, 0, 1, 1, 2023);
+  mypush(now(), 1);
+
+  // print all elements
+  ii = 0;
+  for (cbIter=cbSats.begin(); cbIter<cbSats.end(); ++cbIter) {
+    showBar(ii, *cbIter);
+    ii++;
+  }
+
+  Serial.println("========== Test 3: Print buffer with three elements");
+  setTime( 3, 0, 0, 1, 1, 2023);
+  mypush(now(), 2);
+  mypush(now(), 3);
+
+  // print all elements
+  ii = 0;
+  for (cbIter=cbSats.begin(); cbIter<cbSats.end(); ++cbIter) {
+    showBar(ii, *cbIter);
+    ii++;
+  }
+
+  Serial.println("========== Test 4: Print a full buffer");
+  setTime( 4, 0, 0, 1, 1, 2023);
+  for (int ii=0; ii<130; ii++) {
+    mypush(now(), 4+ii);
+  }
+  // print all elements
+  int bar = 0;
+  for (cbIter=cbSats.begin(); cbIter<cbSats.end(); ++cbIter) {
+    showBar(bar, *cbIter);
+    bar++;
+  }
+
+}
+
+// the loop routine runs over and over again forever:
+void loop() {
+}