[socket] Eliminate heap allocations in set_sockaddr()

esphome/components/socket/socket.cpp

@@ -107,9 +107,9 @@ std::unique_ptr<Socket> socket_ip_loop_monitored(int type, int protocol) {
 #endif /* USE_NETWORK_IPV6 */
 }
 
-socklen_t set_sockaddr(struct sockaddr *addr, socklen_t addrlen, const std::string &ip_address, uint16_t port) {
+socklen_t set_sockaddr(struct sockaddr *addr, socklen_t addrlen, const char *ip_address, uint16_t port) {
 #if USE_NETWORK_IPV6
-  if (ip_address.find(':') != std::string::npos) {
+  if (strchr(ip_address, ':') != nullptr) {
     if (addrlen < sizeof(sockaddr_in6)) {
       errno = EINVAL;
       return 0;
@@ -121,14 +121,14 @@ socklen_t set_sockaddr(struct sockaddr *addr, socklen_t addrlen, const std::stri
 
 #ifdef USE_SOCKET_IMPL_BSD_SOCKETS
     // Use standard inet_pton for BSD sockets
-    if (inet_pton(AF_INET6, ip_address.c_str(), &server->sin6_addr) != 1) {
+    if (inet_pton(AF_INET6, ip_address, &server->sin6_addr) != 1) {
       errno = EINVAL;
       return 0;
     }
 #else
     // Use LWIP-specific functions
     ip6_addr_t ip6;
-    inet6_aton(ip_address.c_str(), &ip6);
+    inet6_aton(ip_address, &ip6);
     memcpy(server->sin6_addr.un.u32_addr, ip6.addr, sizeof(ip6.addr));
 #endif
     return sizeof(sockaddr_in6);
@@ -141,7 +141,7 @@ socklen_t set_sockaddr(struct sockaddr *addr, socklen_t addrlen, const std::stri
   auto *server = reinterpret_cast<sockaddr_in *>(addr);
   memset(server, 0, sizeof(sockaddr_in));
   server->sin_family = AF_INET;
-  server->sin_addr.s_addr = inet_addr(ip_address.c_str());
+  server->sin_addr.s_addr = inet_addr(ip_address);
   server->sin_port = htons(port);
   return sizeof(sockaddr_in);
 }

esphome/components/socket/socket.h

@@ -87,7 +87,17 @@ std::unique_ptr<Socket> socket_loop_monitored(int domain, int type, int protocol
 std::unique_ptr<Socket> socket_ip_loop_monitored(int type, int protocol);
 
 /// Set a sockaddr to the specified address and port for the IP version used by socket_ip().
-socklen_t set_sockaddr(struct sockaddr *addr, socklen_t addrlen, const std::string &ip_address, uint16_t port);
+/// @param addr Destination sockaddr structure
+/// @param addrlen Size of the addr buffer
+/// @param ip_address Null-terminated IP address string (IPv4 or IPv6)
+/// @param port Port number in host byte order
+/// @return Size of the sockaddr structure used, or 0 on error
+socklen_t set_sockaddr(struct sockaddr *addr, socklen_t addrlen, const char *ip_address, uint16_t port);
+
+/// Convenience overload for std::string (backward compatible).
+inline socklen_t set_sockaddr(struct sockaddr *addr, socklen_t addrlen, const std::string &ip_address, uint16_t port) {
+  return set_sockaddr(addr, addrlen, ip_address.c_str(), port);
+}
 
 /// Set a sockaddr to the any address and specified port for the IP version used by socket_ip().
 socklen_t set_sockaddr_any(struct sockaddr *addr, socklen_t addrlen, uint16_t port);

esphome/components/statsd/statsd.cpp

@@ -114,23 +114,14 @@ void StatsdComponent::update() {
     // This implies you can't explicitly set a gauge to a negative number without first setting it to zero.
     if (val < 0) {
       if (this->prefix_) {
-        out.append(this->prefix_);
-        out.append(".");
+        out.append(str_sprintf("%s.", this->prefix_));
       }
-      out.append(s.name);
-      out.append(":0|g\n");
+      out.append(str_sprintf("%s:0|g\n", s.name));
     }
     if (this->prefix_) {
-      out.append(this->prefix_);
-      out.append(".");
+      out.append(str_sprintf("%s.", this->prefix_));
     }
-    out.append(s.name);
-    // Buffer for ":" + value + "|g\n".
-    // %g uses max 13 chars for value (sign + 6 significant digits + e+xxx)
-    // Total: 1 + 13 + 4 = 18 chars + null, use 24 for safety
-    char val_buf[24];
-    snprintf(val_buf, sizeof(val_buf), ":%g|g\n", val);
-    out.append(val_buf);
+    out.append(str_sprintf("%s:%f|g\n", s.name, val));
 
     if (out.length() > SEND_THRESHOLD) {
       this->send_(&out);