Update esphome/components/sml/sml_parser.cpp

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

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/lvgl/lv_validation.py

@@ -413,7 +413,6 @@ class TextValidator(LValidator):
                 str_args = [str(x) for x in value[CONF_ARGS]]
                 arg_expr = cg.RawExpression(",".join(str_args))
                 format_str = cpp_string_escape(format_str)
-                # str_sprintf justified: user-defined format, can't optimize without permanent RAM cost
                 sprintf_str = f"str_sprintf({format_str}, {arg_expr}).c_str()"
                 if nanval := value.get(CONF_IF_NAN):
                     nanval = cpp_string_escape(nanval)

esphome/components/lvgl/lvgl_esphome.cpp

@@ -65,10 +65,7 @@ std::string lv_event_code_name_for(uint8_t event_code) {
   if (event_code < sizeof(EVENT_NAMES) / sizeof(EVENT_NAMES[0])) {
     return EVENT_NAMES[event_code];
   }
-  // max 4 bytes: "%u" with uint8_t (max 255, 3 digits) + null
-  char buf[4];
-  snprintf(buf, sizeof(buf), "%u", event_code);
-  return buf;
+  return str_sprintf("%2d", event_code);
 }
 
 static void rounder_cb(lv_disp_drv_t *disp_drv, lv_area_t *area) {

esphome/components/sml/sml_parser.cpp

@@ -104,7 +104,10 @@ std::vector<ObisInfo> SmlFile::get_obis_info() {
 std::string bytes_repr(const BytesView &buffer) {
   std::string repr;
   for (auto const value : buffer) {
-    repr += str_sprintf("%02x", value & 0xff);
+    // max 3: 2 hex digits + null
+    char hex_buf[3];
+    snprintf(hex_buf, sizeof(hex_buf), "%02x", static_cast<unsigned int>(value));
+    repr += hex_buf;
   }
   return repr;
 }
@@ -146,7 +149,11 @@ ObisInfo::ObisInfo(const BytesView &server_id, const SmlNode &val_list_entry) :
 }
 
 std::string ObisInfo::code_repr() const {
-  return str_sprintf("%d-%d:%d.%d.%d", this->code[0], this->code[1], this->code[2], this->code[3], this->code[4]);
+  // max 20: "255-255:255.255.255" (19 chars) + null
+  char buf[20];
+  snprintf(buf, sizeof(buf), "%d-%d:%d.%d.%d", this->code[0], this->code[1], this->code[2], this->code[3],
+           this->code[4]);
+  return buf;
 }
 
 }  // namespace sml