Hi There,
I'm trying to read the NDEF records stored on my NRF52 DK but I'm having some issues when the the NDEF record payload is less than 4 chars. I just get random symbols or large buffer values instead (See terminal output):
Code:
static char *read_nfc_data()
{
int err;
size_t nfc_length = ndef_msg_buf[1];
uint8_t desc_buf[NFC_NDEF_PARSER_REQIRED_MEMO_SIZE_CALC(10)];
size_t desc_buf_len = sizeof(desc_buf);
// Load NDEF message from flash buffer
err = nfc_ndef_msg_parse(desc_buf, &desc_buf_len, &ndef_msg_buf[2], &nfc_length);
if (err)
{
printk("Error during parsing an NDEF message, err: %d.\n", err);
}
// Parse message into NDEF records
struct nfc_ndef_msg_desc *ndef_message_desc;
ndef_message_desc = (struct nfc_ndef_msg_desc *)desc_buf;
// Iterate over records
for (int i = 0; i < ndef_message_desc->record_count; i++)
{
size_t record_size = nfc_length;
// Extract payload description from NDEF record
struct nfc_ndef_record_desc record_desc = *ndef_message_desc->record[i];
struct nfc_ndef_bin_payload_desc * payload_desc = record_desc.payload_descriptor;
// Remove header from payload to reveal text
int payload_length = payload_desc->payload_length - 3;
char *payload_message = malloc(payload_length + 1);
char *original_message = payload_desc->payload + 3;
// Copy string from buffer to variable with terminator
memcpy(&payload_message, &original_message, payload_length);
payload_message[payload_length] = '\0';
printk("String: %s (%d)\n", payload_message);
}
// Return empty string if failure
return "";
}Terminal Output:
E: CONFIG_MINIMAL_LIBC_MALLOC_ARENA_SIZE is 0
String: Aaaa
E: CONFIG_MINIMAL_LIBC_MALLOC_ARENA_SIZE is 0
String: Hello!
E: CONFIG_MINIMAL_LIBC_MALLOC_ARENA_SIZE is 0
String: ��
m��
^^ The three NDEF values were:
- Aaaa
- Hello!
- A
