[tormatic] Use stack buffers instead of str_sprintf in debug methods

esphome/components/cse7766/cse7766.cpp

@@ -2,7 +2,6 @@
 #include "esphome/core/application.h"
 #include "esphome/core/helpers.h"
 #include "esphome/core/log.h"
-#include <cstdarg>
 
 namespace esphome {
 namespace cse7766 {
@@ -10,32 +9,6 @@ namespace cse7766 {
 static const char *const TAG = "cse7766";
 static constexpr size_t CSE7766_RAW_DATA_SIZE = 24;
 
-#if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERY_VERBOSE
-/// @brief Safely append formatted string to buffer.
-/// @param buf Destination buffer (must be non-null)
-/// @param size Total buffer size in bytes
-/// @param pos Current write position (0 to size-1 for valid positions, size means full)
-/// @param fmt printf-style format string
-/// @return New write position: pos + chars_written, capped at size when buffer is full.
-///         Returns size (not size-1) when full because vsnprintf already wrote the null
-///         terminator at buf[size-1]. Returning size signals "no room for more content".
-///         On encoding error, returns pos unchanged (no write occurred).
-__attribute__((format(printf, 4, 5))) static size_t buf_append(char *buf, size_t size, size_t pos, const char *fmt,
-                                                               ...) {
-  if (pos >= size) {
-    return size;
-  }
-  va_list args;
-  va_start(args, fmt);
-  int written = vsnprintf(buf + pos, size - pos, fmt, args);
-  va_end(args);
-  if (written < 0) {
-    return pos;  // encoding error
-  }
-  return std::min(pos + static_cast<size_t>(written), size);
-}
-#endif
-
 void CSE7766Component::loop() {
   const uint32_t now = App.get_loop_component_start_time();
   if (now - this->last_transmission_ >= 500) {
@@ -234,23 +207,20 @@ void CSE7766Component::parse_data_() {
 
 #if ESPHOME_LOG_LEVEL >= ESPHOME_LOG_LEVEL_VERY_VERBOSE
   {
-    // Buffer: 7 + 15 + 33 + 15 + 25 = 95 chars max + null, rounded to 128 for safety margin.
-    // Float sizes with %.4f can be up to 11 chars for large values (e.g., 999999.9999).
-    char buf[128];
-    size_t pos = buf_append(buf, sizeof(buf), 0, "Parsed:");
+    std::string buf = "Parsed:";
     if (have_voltage) {
-      pos = buf_append(buf, sizeof(buf), pos, " V=%.4fV", voltage);
+      buf += str_sprintf(" V=%fV", voltage);
     }
     if (have_current) {
-      pos = buf_append(buf, sizeof(buf), pos, " I=%.4fmA (~%.4fmA)", current * 1000.0f, calculated_current * 1000.0f);
+      buf += str_sprintf(" I=%fmA (~%fmA)", current * 1000.0f, calculated_current * 1000.0f);
     }
     if (have_power) {
-      pos = buf_append(buf, sizeof(buf), pos, " P=%.4fW", power);
+      buf += str_sprintf(" P=%fW", power);
     }
     if (energy != 0.0f) {
-      buf_append(buf, sizeof(buf), pos, " E=%.4fkWh (%u)", energy, cf_pulses);
+      buf += str_sprintf(" E=%fkWh (%u)", energy, cf_pulses);
     }
-    ESP_LOGVV(TAG, "%s", buf);
+    ESP_LOGVV(TAG, "%s", buf.c_str());
   }
 #endif
 }

esphome/components/tormatic/tormatic_protocol.h

@@ -55,6 +55,7 @@ enum MessageType : uint16_t {
   COMMAND = 0x0106,
 };
 
+// Max string length: 7 ("Unknown"/"Command"). Update print() buffer sizes if adding longer strings.
 inline const char *message_type_to_str(MessageType t) {
   switch (t) {
     case STATUS:
@@ -83,7 +84,11 @@ struct MessageHeader {
   }
 
   std::string print() {
-    return str_sprintf("MessageHeader: seq %d, len %d, type %s", this->seq, this->len, message_type_to_str(this->type));
+    // 64 bytes: "MessageHeader: seq " + uint16 + ", len " + uint32 + ", type " + type + safety margin
+    char buf[64];
+    snprintf(buf, sizeof(buf), "MessageHeader: seq %d, len %d, type %s", this->seq, this->len,
+             message_type_to_str(this->type));
+    return buf;
   }
 
   void byteswap() {
@@ -131,6 +136,7 @@ inline CoverOperation gate_status_to_cover_operation(GateStatus s) {
   return COVER_OPERATION_IDLE;
 }
 
+// Max string length: 11 ("Ventilating"). Update print() buffer sizes if adding longer strings.
 inline const char *gate_status_to_str(GateStatus s) {
   switch (s) {
     case PAUSED:
@@ -170,7 +176,12 @@ struct StatusReply {
   GateStatus state;
   uint8_t trailer = 0x0;
 
-  std::string print() { return str_sprintf("StatusReply: state %s", gate_status_to_str(this->state)); }
+  std::string print() {
+    // 48 bytes: "StatusReply: state " (19) + state (11) + safety margin
+    char buf[48];
+    snprintf(buf, sizeof(buf), "StatusReply: state %s", gate_status_to_str(this->state));
+    return buf;
+  }
 
   void byteswap(){};
 } __attribute__((packed));
@@ -202,7 +213,12 @@ struct CommandRequestReply {
   CommandRequestReply() = default;
   CommandRequestReply(GateStatus state) { this->state = state; }
 
-  std::string print() { return str_sprintf("CommandRequestReply: state %s", gate_status_to_str(this->state)); }
+  std::string print() {
+    // 56 bytes: "CommandRequestReply: state " (27) + state (11) + safety margin
+    char buf[56];
+    snprintf(buf, sizeof(buf), "CommandRequestReply: state %s", gate_status_to_str(this->state));
+    return buf;
+  }
 
   void byteswap() { this->type = convert_big_endian(this->type); }
 } __attribute__((packed));