SML runtime optimizations (#8571)

esphome/components/sml/sml_parser.cpp

@@ -5,17 +5,17 @@
 namespace esphome {
 namespace sml {
 
-SmlFile::SmlFile(bytes buffer) : buffer_(std::move(buffer)) {
+SmlFile::SmlFile(const BytesView &buffer) : buffer_(buffer) {
   // extract messages
   this->pos_ = 0;
   while (this->pos_ < this->buffer_.size()) {
     if (this->buffer_[this->pos_] == 0x00)
       break;  // EndOfSmlMsg
 
-    SmlNode message = SmlNode();
+    SmlNode message;
     if (!this->setup_node(&message))
       break;
-    this->messages.emplace_back(message);
+    this->messages.emplace_back(std::move(message));
   }
 }
 
@@ -62,22 +62,20 @@ bool SmlFile::setup_node(SmlNode *node) {
     return false;
 
   node->type = type;
-  node->nodes.clear();
-  node->value_bytes.clear();
 
   if (type == SML_LIST) {
     node->nodes.reserve(length);
     for (size_t i = 0; i != length; i++) {
-      SmlNode child_node = SmlNode();
+      SmlNode child_node;
       if (!this->setup_node(&child_node))
         return false;
-      node->nodes.emplace_back(child_node);
+      node->nodes.emplace_back(std::move(child_node));
     }
   } else {
     // Value starts at the current position
     // Value ends "length" bytes later,
     // (since the TL field is counted but already subtracted from length)
-    node->value_bytes = bytes(this->buffer_.begin() + this->pos_, this->buffer_.begin() + this->pos_ + length);
+    node->value_bytes = buffer_.subview(this->pos_, length);
     // Increment the pointer past all consumed bytes
     this->pos_ += length;
   }
@@ -87,14 +85,14 @@ bool SmlFile::setup_node(SmlNode *node) {
 std::vector<ObisInfo> SmlFile::get_obis_info() {
   std::vector<ObisInfo> obis_info;
   for (auto const &message : messages) {
-    SmlNode message_body = message.nodes[3];
+    const auto &message_body = message.nodes[3];
     uint16_t message_type = bytes_to_uint(message_body.nodes[0].value_bytes);
     if (message_type != SML_GET_LIST_RES)
       continue;
 
-    SmlNode get_list_response = message_body.nodes[1];
-    bytes server_id = get_list_response.nodes[1].value_bytes;
-    SmlNode val_list = get_list_response.nodes[4];
+    const auto &get_list_response = message_body.nodes[1];
+    const auto &server_id = get_list_response.nodes[1].value_bytes;
+    const auto &val_list = get_list_response.nodes[4];
 
     for (auto const &val_list_entry : val_list.nodes) {
       obis_info.emplace_back(server_id, val_list_entry);
@@ -103,7 +101,7 @@ std::vector<ObisInfo> SmlFile::get_obis_info() {
   return obis_info;
 }
 
-std::string bytes_repr(const bytes &buffer) {
+std::string bytes_repr(const BytesView &buffer) {
   std::string repr;
   for (auto const value : buffer) {
     repr += str_sprintf("%02x", value & 0xff);
@@ -111,7 +109,7 @@ std::string bytes_repr(const bytes &buffer) {
   return repr;
 }
 
-uint64_t bytes_to_uint(const bytes &buffer) {
+uint64_t bytes_to_uint(const BytesView &buffer) {
   uint64_t val = 0;
   for (auto const value : buffer) {
     val = (val << 8) + value;
@@ -119,7 +117,7 @@ uint64_t bytes_to_uint(const bytes &buffer) {
   return val;
 }
 
-int64_t bytes_to_int(const bytes &buffer) {
+int64_t bytes_to_int(const BytesView &buffer) {
   uint64_t tmp = bytes_to_uint(buffer);
   int64_t val;
 
@@ -135,14 +133,14 @@ int64_t bytes_to_int(const bytes &buffer) {
   return val;
 }
 
-std::string bytes_to_string(const bytes &buffer) { return std::string(buffer.begin(), buffer.end()); }
+std::string bytes_to_string(const BytesView &buffer) { return std::string(buffer.begin(), buffer.end()); }
 
-ObisInfo::ObisInfo(bytes server_id, SmlNode val_list_entry) : server_id(std::move(server_id)) {
+ObisInfo::ObisInfo(const BytesView &server_id, const SmlNode &val_list_entry) : server_id(server_id) {
   this->code = val_list_entry.nodes[0].value_bytes;
   this->status = val_list_entry.nodes[1].value_bytes;
   this->unit = bytes_to_uint(val_list_entry.nodes[3].value_bytes);
   this->scaler = bytes_to_int(val_list_entry.nodes[4].value_bytes);
-  SmlNode value_node = val_list_entry.nodes[5];
+  const auto &value_node = val_list_entry.nodes[5];
   this->value = value_node.value_bytes;
   this->value_type = value_node.type;
 }