From f304d049d18cece2ec67813250c08ae5a987c2e3 Mon Sep 17 00:00:00 2001
From: Andrea Gilardoni <a.gilardoni@arduino.cc>
Date: Mon, 10 Mar 2025 13:25:09 +0100
Subject: [PATCH] testing usage of linkedlists for cbor decoder singleton

---
 src/cbor/MessageDecoder.cpp | 32 +++++++++++++++++++++-----------
 src/cbor/MessageDecoder.h   |  8 ++++++--
 2 files changed, 27 insertions(+), 13 deletions(-)

diff --git a/src/cbor/MessageDecoder.cpp b/src/cbor/MessageDecoder.cpp
index ae630cd..c912903 100644
--- a/src/cbor/MessageDecoder.cpp
+++ b/src/cbor/MessageDecoder.cpp
@@ -31,21 +31,21 @@ MessageDecoder::Status CBORMessageDecoderSingleton::decode(Message* msg, const u
     return MessageDecoder::Status::Error;
   }
 
-  auto decoder_it = decoders.begin();
+  struct llnode* decoder_it = decoders;
 
-  for(; decoder_it != decoders.end(); decoder_it++) {
-    if(decoder_it->first == tag) {
+  for(; decoder_it != nullptr; decoder_it = decoder_it->next) {
+    if(decoder_it->tag == tag) {
       break;
     }
   }
 
   // check if message.id exists on the decoders list or return error
-  if(decoder_it == decoders.end()) {
+  if(decoder_it == nullptr) {
     return MessageDecoder::Status::Error;
   }
 
   // encode the message
-  if(decoder_it->second->_decode(&iter, msg) == MessageDecoder::Status::Error) {
+  if(decoder_it->decoder->_decode(&iter, msg) == MessageDecoder::Status::Error) {
     return MessageDecoder::Status::Error;
   }
 
@@ -59,17 +59,27 @@ CBORMessageDecoderSingleton& CBORMessageDecoderSingleton::getInstance() {
 }
 
 void CBORMessageDecoderSingleton::append(CBORTag tag, CBORMessageDecoderInterface* decoder) {
-    auto decoder_it = decoders.begin();
+  struct llnode* decoder_it = decoders;
 
-  for(; decoder_it != decoders.end(); decoder_it++) {
-    if(decoder_it->first == tag) {
+  for(; decoder_it != nullptr; decoder_it = decoder_it->next) {
+    if(decoder_it->tag == tag) {
       return;
     }
   }
 
-  decoders.push_back(
-    std::make_pair(tag, decoder)
-  );
+  struct llnode* next = new llnode;
+
+  next->tag = tag;
+  next->decoder = decoder;
+
+  // this is the first element
+  if(decoders == nullptr) {
+    decoders = next;
+  } else {
+    decoders_last->next = next;
+  }
+
+  decoders_last = next;
 }
 
 CBORMessageDecoderInterface::CBORMessageDecoderInterface(const CBORTag tag, const MessageId id)
diff --git a/src/cbor/MessageDecoder.h b/src/cbor/MessageDecoder.h
index 1a9bf58..a722f0e 100644
--- a/src/cbor/MessageDecoder.h
+++ b/src/cbor/MessageDecoder.h
@@ -107,9 +107,13 @@ class CBORMessageDecoderSingleton: public MessageDecoder {
    */
   MessageDecoder::Status decode(Message* msg, const uint8_t* const buf, size_t &len);
 private:
-  CBORMessageDecoderSingleton() {}
+  CBORMessageDecoderSingleton(): decoders(nullptr), decoders_last(nullptr) { }
 
-  std::vector<std::pair<CBORTag, CBORMessageDecoderInterface*>> decoders;
+  struct llnode {
+    struct llnode* next;
+    CBORTag tag;
+    CBORMessageDecoderInterface* decoder;
+  } *decoders, *decoders_last;
 };
 
 /**