esphome/esphome/components/nfc/ndef_message.cpp
2021-12-02 09:03:51 +13:00

104 lines
3.5 KiB
C++

#include "ndef_message.h"
namespace esphome {
namespace nfc {
static const char *const TAG = "nfc.ndef_message";
NdefMessage::NdefMessage(std::vector<uint8_t> &data) {
ESP_LOGV(TAG, "Building NdefMessage with %zu bytes", data.size());
uint8_t index = 0;
while (index <= data.size()) {
uint8_t tnf_byte = data[index++];
bool me = tnf_byte & 0x40; // Message End bit (is set if this is the last record of the message)
bool sr = tnf_byte & 0x10; // Short record bit (is set if payload size is less or equal to 255 bytes)
bool il = tnf_byte & 0x08; // ID length bit (is set if ID Length field exists)
uint8_t tnf = tnf_byte & 0x07; // Type Name Format
ESP_LOGVV(TAG, "me=%s, sr=%s, il=%s, tnf=%d", YESNO(me), YESNO(sr), YESNO(il), tnf);
uint8_t type_length = data[index++];
uint32_t payload_length = 0;
if (sr) {
payload_length = data[index++];
} else {
payload_length = (static_cast<uint32_t>(data[index]) << 24) | (static_cast<uint32_t>(data[index + 1]) << 16) |
(static_cast<uint32_t>(data[index + 2]) << 8) | static_cast<uint32_t>(data[index + 3]);
index += 4;
}
uint8_t id_length = 0;
if (il) {
id_length = data[index++];
}
ESP_LOGVV(TAG, "Lengths: type=%d, payload=%d, id=%d", type_length, payload_length, id_length);
std::string type_str(data.begin() + index, data.begin() + index + type_length);
index += type_length;
std::string id_str = "";
if (il) {
id_str = std::string(data.begin() + index, data.begin() + index + id_length);
index += id_length;
}
std::vector<uint8_t> payload_data(data.begin() + index, data.begin() + index + payload_length);
std::unique_ptr<NdefRecord> record;
// Based on tnf and type, create a more specific NdefRecord object
// constructed from the payload data
if (tnf == TNF_WELL_KNOWN && type_str == "U") {
record = make_unique<NdefRecordUri>(payload_data);
} else if (tnf == TNF_WELL_KNOWN && type_str == "T") {
record = make_unique<NdefRecordText>(payload_data);
} else {
// Could not recognize the record, so store as generic one.
record = make_unique<NdefRecord>(payload_data);
record->set_tnf(tnf);
record->set_type(type_str);
}
record->set_id(id_str);
index += payload_length;
ESP_LOGV(TAG, "Adding record type %s = %s", record->get_type().c_str(), record->get_payload().c_str());
this->add_record(std::move(record));
if (me)
break;
}
}
bool NdefMessage::add_record(std::unique_ptr<NdefRecord> record) {
if (this->records_.size() >= MAX_NDEF_RECORDS) {
ESP_LOGE(TAG, "Too many records. Max: %d", MAX_NDEF_RECORDS);
return false;
}
this->records_.emplace_back(std::move(record));
return true;
}
bool NdefMessage::add_text_record(const std::string &text) { return this->add_text_record(text, "en"); };
bool NdefMessage::add_text_record(const std::string &text, const std::string &encoding) {
return this->add_record(make_unique<NdefRecordText>(encoding, text));
}
bool NdefMessage::add_uri_record(const std::string &uri) { return this->add_record(make_unique<NdefRecordUri>(uri)); }
std::vector<uint8_t> NdefMessage::encode() {
std::vector<uint8_t> data;
for (size_t i = 0; i < this->records_.size(); i++) {
auto encoded_record = this->records_[i]->encode(i == 0, (i + 1) == this->records_.size());
data.insert(data.end(), encoded_record.begin(), encoded_record.end());
}
return data;
}
} // namespace nfc
} // namespace esphome