Add NDEF reading and writing to PN532 (#1351)

esphome/components/nfc/ndef_record.cpp

@@ -0,0 +1,85 @@
+#include "ndef_record.h"
+
+namespace esphome {
+namespace nfc {
+
+static const char* TAG = "nfc.ndef_record";
+
+uint32_t NdefRecord::get_encoded_size() {
+  uint32_t size = 2;
+  if (this->payload_.length() > 255) {
+    size += 4;
+  } else {
+    size += 1;
+  }
+  if (this->id_.length()) {
+    size += 1;
+  }
+  size += (this->type_.length() + this->payload_.length() + this->id_.length());
+  return size;
+}
+
+std::vector<uint8_t> NdefRecord::encode(bool first, bool last) {
+  std::vector<uint8_t> data;
+
+  data.push_back(this->get_tnf_byte(first, last));
+
+  data.push_back(this->type_.length());
+
+  uint8_t payload_prefix = 0x00;
+  uint8_t payload_prefix_length = 0x00;
+  for (uint8_t i = 1; i < PAYLOAD_IDENTIFIERS_COUNT; i++) {
+    std::string prefix = PAYLOAD_IDENTIFIERS[i];
+    if (this->payload_.substr(0, prefix.length()).find(prefix) != std::string::npos) {
+      payload_prefix = i;
+      payload_prefix_length = prefix.length();
+      break;
+    }
+  }
+
+  uint32_t payload_length = this->payload_.length() - payload_prefix_length + 1;
+
+  if (payload_length <= 255) {
+    data.push_back(payload_length);
+  } else {
+    data.push_back(0);
+    data.push_back(0);
+    data.push_back((payload_length >> 8) & 0xFF);
+    data.push_back(payload_length & 0xFF);
+  }
+
+  if (this->id_.length()) {
+    data.push_back(this->id_.length());
+  }
+
+  data.insert(data.end(), this->type_.begin(), this->type_.end());
+
+  if (this->id_.length()) {
+    data.insert(data.end(), this->id_.begin(), this->id_.end());
+  }
+
+  data.push_back(payload_prefix);
+
+  data.insert(data.end(), this->payload_.begin() + payload_prefix_length, this->payload_.end());
+  return data;
+}
+
+uint8_t NdefRecord::get_tnf_byte(bool first, bool last) {
+  uint8_t value = this->tnf_;
+  if (first) {
+    value = value | 0x80;
+  }
+  if (last) {
+    value = value | 0x40;
+  }
+  if (this->payload_.length() <= 255) {
+    value = value | 0x10;
+  }
+  if (this->id_.length()) {
+    value = value | 0x08;
+  }
+  return value;
+};
+
+}  // namespace nfc
+}  // namespace esphome