[opentherm] Fix out of memory errors on ESP8266 (#7835)

esphome/core/helpers.cpp

@@ -397,6 +397,18 @@ std::string format_hex_pretty(const uint16_t *data, size_t length) {
 }
 std::string format_hex_pretty(const std::vector<uint16_t> &data) { return format_hex_pretty(data.data(), data.size()); }
 
+std::string format_bin(const uint8_t *data, size_t length) {
+  std::string result;
+  result.resize(length * 8);
+  for (size_t byte_idx = 0; byte_idx < length; byte_idx++) {
+    for (size_t bit_idx = 0; bit_idx < 8; bit_idx++) {
+      result[byte_idx * 8 + bit_idx] = ((data[byte_idx] >> (7 - bit_idx)) & 1) + '0';
+    }
+  }
+
+  return result;
+}
+
 ParseOnOffState parse_on_off(const char *str, const char *on, const char *off) {
   if (on == nullptr && strcasecmp(str, "on") == 0)
     return PARSE_ON;