Declare the prefix pointer as const auto *

esphome/components/nfc/ndef_record_uri.cpp

@@ -1,9 +1,18 @@
 #include "ndef_record_uri.h"
+#include "esphome/core/progmem.h"
 
 namespace esphome::nfc {
 
 ESPHOME_LOG_TAG(TAG, "nfc.ndef_record_uri");
 
+// URI identifier codes from the NFC Forum URI record type definition
+PROGMEM_STRING_TABLE(UriPrefixStrings, "", "http://www.", "https://www.", "http://", "https://",
+                     "tel:", "mailto:", "ftp://anonymous:anonymous@", "ftp://ftp.", "ftps://", "sftp://", "smb://",
+                     "nfs://", "ftp://", "dav://", "news:", "telnet://", "imap:", "rtsp://",
+                     "urn:", "pop:", "sip:", "sips:", "tftp:", "btspp://", "btl2cap://", "btgoep://", "tcpobex://",
+                     "irdaobex://", "file://",
+                     "urn:epc:id:", "urn:epc:tag:", "urn:epc:pat:", "urn:epc:raw:", "urn:epc:", "urn:nfc:");
+
 NdefRecordUri::NdefRecordUri(const std::vector<uint8_t> &payload) {
   if (payload.empty()) {
     ESP_LOGE(TAG, "Record payload too short");
@@ -14,8 +23,11 @@ NdefRecordUri::NdefRecordUri(const std::vector<uint8_t> &payload) {
 
   std::string uri(payload.begin() + 1, payload.end());
 
-  if (payload_identifier > 0x00 && payload_identifier <= PAYLOAD_IDENTIFIERS_COUNT) {
-    uri.insert(0, PAYLOAD_IDENTIFIERS[payload_identifier]);
+  if (payload_identifier > 0x00 && payload_identifier <= UriPrefixStrings::LAST_INDEX) {
+    char prefix[UriPrefixStrings::MAX_LENGTH + 1];
+    ESPHOME_strncpy_P(prefix, reinterpret_cast<ESPHOME_PGM_P>(UriPrefixStrings::get_progmem_str(payload_identifier, 0)),
+                      sizeof(prefix));
+    uri.insert(0, prefix);
   }
 
   this->tnf_ = TNF_WELL_KNOWN;
@@ -28,11 +40,12 @@ std::vector<uint8_t> NdefRecordUri::get_encoded_payload() {
 
   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->uri_.substr(0, prefix.length()).find(prefix) != std::string::npos) {
+  for (uint8_t i = 1; i < UriPrefixStrings::LAST_INDEX; i++) {
+    const auto *prefix = reinterpret_cast<ESPHOME_PGM_P>(UriPrefixStrings::get_progmem_str(i, 0));
+    const size_t length = ESPHOME_strlen_P(prefix);
+    if (this->uri_.size() >= length && ESPHOME_strncmp_P(this->uri_.c_str(), prefix, length) == 0) {
       payload_prefix = i;
-      payload_prefix_length = prefix.length();
+      payload_prefix_length = length;
       break;
     }
   }

esphome/components/nfc/ndef_record_uri.h

@@ -8,44 +8,6 @@
 
 namespace esphome::nfc {
 
-static constexpr uint8_t PAYLOAD_IDENTIFIERS_COUNT = 0x23;
-static const char *const PAYLOAD_IDENTIFIERS[] = {"",
-                                                  "http://www.",
-                                                  "https://www.",
-                                                  "http://",
-                                                  "https://",
-                                                  "tel:",
-                                                  "mailto:",
-                                                  "ftp://anonymous:anonymous@",
-                                                  "ftp://ftp.",
-                                                  "ftps://",
-                                                  "sftp://",
-                                                  "smb://",
-                                                  "nfs://",
-                                                  "ftp://",
-                                                  "dav://",
-                                                  "news:",
-                                                  "telnet://",
-                                                  "imap:",
-                                                  "rtsp://",
-                                                  "urn:",
-                                                  "pop:",
-                                                  "sip:",
-                                                  "sips:",
-                                                  "tftp:",
-                                                  "btspp://",
-                                                  "btl2cap://",
-                                                  "btgoep://",
-                                                  "tcpobex://",
-                                                  "irdaobex://",
-                                                  "file://",
-                                                  "urn:epc:id:",
-                                                  "urn:epc:tag:",
-                                                  "urn:epc:pat:",
-                                                  "urn:epc:raw:",
-                                                  "urn:epc:",
-                                                  "urn:nfc:"};
-
 class NdefRecordUri : public NdefRecord {
  public:
   NdefRecordUri(){};