Added support for retrieving energy price from ENTSO-E API

src/entsoe/DnbCurrParser.cpp

@@ -0,0 +1,60 @@
+#include "DnbCurrParser.h"
+#include "HardwareSerial.h"
+
+double DnbCurrParser::getValue() {
+    return value;
+}
+
+int DnbCurrParser::available() {
+
+}
+
+int DnbCurrParser::read() {
+
+}
+
+int DnbCurrParser::peek() {
+
+}
+
+void DnbCurrParser::flush() {
+
+}
+
+size_t DnbCurrParser::write(const uint8_t *buffer, size_t size) {
+    for(int i = 0; i < size; i++) {
+        write(buffer[i]);
+    }
+    return size;
+}
+
+size_t DnbCurrParser::write(uint8_t byte) {
+    if(pos == 0) {
+        if(byte == '<') {
+            buf[pos++] = byte;
+        }
+    } else if(byte == '>') {
+        buf[pos++] = byte;
+        if(strncmp(buf, "<Obs", 4) == 0) {
+            for(int i = 0; i < pos; i++) {
+                if(strncmp(buf+i, "OBS_VALUE=\"", 11) == 0) {
+                    pos = i + 11;
+                    break;
+                }
+            }
+            for(int i = 0; i < 16; i++) {
+                uint8_t b = buf[pos+i];
+                if(b == '"') {
+                    buf[pos+i] = '\0';
+                    break;
+                }
+            }
+            value = String(buf+pos).toDouble();
+        }
+        pos = 0;
+    } else {
+        buf[pos++] = byte;
+    }
+
+    return 1;
+}