diff --git a/esphome/components/web_server/web_server.cpp b/esphome/components/web_server/web_server.cpp index b0731f335b..df8a5364cf 100644 --- a/esphome/components/web_server/web_server.cpp +++ b/esphome/components/web_server/web_server.cpp @@ -432,7 +432,7 @@ static void set_json_value(JsonObject &root, EntityBase *obj, const char *prefix } template -static void set_json_icon_state_value(JsonObject &root, EntityBase *obj, const char *prefix, const std::string &state, +static void set_json_icon_state_value(JsonObject &root, EntityBase *obj, const char *prefix, const char *state, const T &value, JsonDetail start_config) { set_json_value(root, obj, prefix, value, start_config); root[ESPHOME_F("state")] = state; @@ -475,9 +475,10 @@ std::string WebServer::sensor_json_(sensor::Sensor *obj, float value, JsonDetail JsonObject root = builder.root(); const auto uom_ref = obj->get_unit_of_measurement_ref(); - - std::string state = - std::isnan(value) ? "NA" : value_accuracy_with_uom_to_string(value, obj->get_accuracy_decimals(), uom_ref); + char buf[VALUE_ACCURACY_MAX_LEN]; + const char *state = std::isnan(value) + ? "NA" + : (value_accuracy_with_uom_to_buf(buf, value, obj->get_accuracy_decimals(), uom_ref), buf); set_json_icon_state_value(root, obj, "sensor", state, value, start_config); if (start_config == DETAIL_ALL) { this->add_sorting_info_(root, obj); @@ -522,7 +523,7 @@ std::string WebServer::text_sensor_json_(text_sensor::TextSensor *obj, const std json::JsonBuilder builder; JsonObject root = builder.root(); - set_json_icon_state_value(root, obj, "text_sensor", value, value, start_config); + set_json_icon_state_value(root, obj, "text_sensor", value.c_str(), value.c_str(), start_config); if (start_config == DETAIL_ALL) { this->add_sorting_info_(root, obj); } @@ -974,21 +975,20 @@ std::string WebServer::number_json_(number::Number *obj, float value, JsonDetail JsonObject root = builder.root(); const auto uom_ref = obj->traits.get_unit_of_measurement_ref(); + const int8_t accuracy = step_to_accuracy_decimals(obj->traits.get_step()); - std::string val_str = std::isnan(value) - ? "\"NaN\"" - : value_accuracy_to_string(value, step_to_accuracy_decimals(obj->traits.get_step())); - std::string state_str = std::isnan(value) ? "NA" - : value_accuracy_with_uom_to_string( - value, step_to_accuracy_decimals(obj->traits.get_step()), uom_ref); + // Need two buffers: one for value, one for state with UOM + char val_buf[VALUE_ACCURACY_MAX_LEN]; + char state_buf[VALUE_ACCURACY_MAX_LEN]; + const char *val_str = std::isnan(value) ? "\"NaN\"" : (value_accuracy_to_buf(val_buf, value, accuracy), val_buf); + const char *state_str = + std::isnan(value) ? "NA" : (value_accuracy_with_uom_to_buf(state_buf, value, accuracy, uom_ref), state_buf); set_json_icon_state_value(root, obj, "number", state_str, val_str, start_config); if (start_config == DETAIL_ALL) { - root[ESPHOME_F("min_value")] = - value_accuracy_to_string(obj->traits.get_min_value(), step_to_accuracy_decimals(obj->traits.get_step())); - root[ESPHOME_F("max_value")] = - value_accuracy_to_string(obj->traits.get_max_value(), step_to_accuracy_decimals(obj->traits.get_step())); - root[ESPHOME_F("step")] = - value_accuracy_to_string(obj->traits.get_step(), step_to_accuracy_decimals(obj->traits.get_step())); + // ArduinoJson copies the string immediately, so we can reuse val_buf + root[ESPHOME_F("min_value")] = (value_accuracy_to_buf(val_buf, obj->traits.get_min_value(), accuracy), val_buf); + root[ESPHOME_F("max_value")] = (value_accuracy_to_buf(val_buf, obj->traits.get_max_value(), accuracy), val_buf); + root[ESPHOME_F("step")] = (value_accuracy_to_buf(val_buf, obj->traits.get_step(), accuracy), val_buf); root[ESPHOME_F("mode")] = (int) obj->traits.get_mode(); if (!uom_ref.empty()) root[ESPHOME_F("uom")] = uom_ref; @@ -1230,8 +1230,8 @@ std::string WebServer::text_json_(text::Text *obj, const std::string &value, Jso json::JsonBuilder builder; JsonObject root = builder.root(); - std::string state = obj->traits.get_mode() == text::TextMode::TEXT_MODE_PASSWORD ? "********" : value; - set_json_icon_state_value(root, obj, "text", state, value, start_config); + const char *state = obj->traits.get_mode() == text::TextMode::TEXT_MODE_PASSWORD ? "********" : value.c_str(); + set_json_icon_state_value(root, obj, "text", state, value.c_str(), start_config); root[ESPHOME_F("min_length")] = obj->traits.get_min_length(); root[ESPHOME_F("max_length")] = obj->traits.get_max_length(); root[ESPHOME_F("pattern")] = obj->traits.get_pattern_c_str(); @@ -1359,6 +1359,7 @@ std::string WebServer::climate_json_(climate::Climate *obj, JsonDetail start_con int8_t target_accuracy = traits.get_target_temperature_accuracy_decimals(); int8_t current_accuracy = traits.get_current_temperature_accuracy_decimals(); char buf[PSTR_LOCAL_SIZE]; + char temp_buf[VALUE_ACCURACY_MAX_LEN]; if (start_config == DETAIL_ALL) { JsonArray opt = root[ESPHOME_F("modes")].to(); @@ -1395,8 +1396,10 @@ std::string WebServer::climate_json_(climate::Climate *obj, JsonDetail start_con bool has_state = false; root[ESPHOME_F("mode")] = PSTR_LOCAL(climate_mode_to_string(obj->mode)); - root[ESPHOME_F("max_temp")] = value_accuracy_to_string(traits.get_visual_max_temperature(), target_accuracy); - root[ESPHOME_F("min_temp")] = value_accuracy_to_string(traits.get_visual_min_temperature(), target_accuracy); + root[ESPHOME_F("max_temp")] = + (value_accuracy_to_buf(temp_buf, traits.get_visual_max_temperature(), target_accuracy), temp_buf); + root[ESPHOME_F("min_temp")] = + (value_accuracy_to_buf(temp_buf, traits.get_visual_min_temperature(), target_accuracy), temp_buf); root[ESPHOME_F("step")] = traits.get_visual_target_temperature_step(); if (traits.has_feature_flags(climate::CLIMATE_SUPPORTS_ACTION)) { root[ESPHOME_F("action")] = PSTR_LOCAL(climate_action_to_string(obj->action)); @@ -1419,23 +1422,26 @@ std::string WebServer::climate_json_(climate::Climate *obj, JsonDetail start_con root[ESPHOME_F("swing_mode")] = PSTR_LOCAL(climate_swing_mode_to_string(obj->swing_mode)); } if (traits.has_feature_flags(climate::CLIMATE_SUPPORTS_CURRENT_TEMPERATURE)) { - if (!std::isnan(obj->current_temperature)) { - root[ESPHOME_F("current_temperature")] = value_accuracy_to_string(obj->current_temperature, current_accuracy); - } else { - root[ESPHOME_F("current_temperature")] = "NA"; - } + root[ESPHOME_F("current_temperature")] = + std::isnan(obj->current_temperature) + ? "NA" + : (value_accuracy_to_buf(temp_buf, obj->current_temperature, current_accuracy), temp_buf); } if (traits.has_feature_flags(climate::CLIMATE_SUPPORTS_TWO_POINT_TARGET_TEMPERATURE | climate::CLIMATE_REQUIRES_TWO_POINT_TARGET_TEMPERATURE)) { - root[ESPHOME_F("target_temperature_low")] = value_accuracy_to_string(obj->target_temperature_low, target_accuracy); + root[ESPHOME_F("target_temperature_low")] = + (value_accuracy_to_buf(temp_buf, obj->target_temperature_low, target_accuracy), temp_buf); root[ESPHOME_F("target_temperature_high")] = - value_accuracy_to_string(obj->target_temperature_high, target_accuracy); + (value_accuracy_to_buf(temp_buf, obj->target_temperature_high, target_accuracy), temp_buf); if (!has_state) { - root[ESPHOME_F("state")] = value_accuracy_to_string( - (obj->target_temperature_high + obj->target_temperature_low) / 2.0f, target_accuracy); + root[ESPHOME_F("state")] = + (value_accuracy_to_buf(temp_buf, (obj->target_temperature_high + obj->target_temperature_low) / 2.0f, + target_accuracy), + temp_buf); } } else { - root[ESPHOME_F("target_temperature")] = value_accuracy_to_string(obj->target_temperature, target_accuracy); + root[ESPHOME_F("target_temperature")] = + (value_accuracy_to_buf(temp_buf, obj->target_temperature, target_accuracy), temp_buf); if (!has_state) root[ESPHOME_F("state")] = root[ESPHOME_F("target_temperature")]; } diff --git a/esphome/core/helpers.cpp b/esphome/core/helpers.cpp index f55f53f16b..d7d32ea28f 100644 --- a/esphome/core/helpers.cpp +++ b/esphome/core/helpers.cpp @@ -383,23 +383,33 @@ static inline void normalize_accuracy_decimals(float &value, int8_t &accuracy_de } std::string value_accuracy_to_string(float value, int8_t accuracy_decimals) { - normalize_accuracy_decimals(value, accuracy_decimals); - char tmp[32]; // should be enough, but we should maybe improve this at some point. - snprintf(tmp, sizeof(tmp), "%.*f", accuracy_decimals, value); - return std::string(tmp); + char buf[VALUE_ACCURACY_MAX_LEN]; + value_accuracy_to_buf(buf, value, accuracy_decimals); + return std::string(buf); } -std::string value_accuracy_with_uom_to_string(float value, int8_t accuracy_decimals, StringRef unit_of_measurement) { +size_t value_accuracy_to_buf(std::span buf, float value, int8_t accuracy_decimals) { normalize_accuracy_decimals(value, accuracy_decimals); - // Buffer sized for float (up to ~15 chars) + space + typical UOM (usually <20 chars like "μS/cm") - // snprintf truncates safely if exceeded, though ESPHome UOMs are typically short - char tmp[64]; + // snprintf returns chars that would be written (excluding null), or negative on error + int len = snprintf(buf.data(), buf.size(), "%.*f", accuracy_decimals, value); + if (len < 0) + return 0; // encoding error + // On truncation, snprintf returns would-be length; actual written is buf.size() - 1 + return static_cast(len) >= buf.size() ? buf.size() - 1 : static_cast(len); +} + +size_t value_accuracy_with_uom_to_buf(std::span buf, float value, + int8_t accuracy_decimals, StringRef unit_of_measurement) { if (unit_of_measurement.empty()) { - snprintf(tmp, sizeof(tmp), "%.*f", accuracy_decimals, value); - } else { - snprintf(tmp, sizeof(tmp), "%.*f %s", accuracy_decimals, value, unit_of_measurement.c_str()); + return value_accuracy_to_buf(buf, value, accuracy_decimals); } - return std::string(tmp); + normalize_accuracy_decimals(value, accuracy_decimals); + // snprintf returns chars that would be written (excluding null), or negative on error + int len = snprintf(buf.data(), buf.size(), "%.*f %s", accuracy_decimals, value, unit_of_measurement.c_str()); + if (len < 0) + return 0; // encoding error + // On truncation, snprintf returns would-be length; actual written is buf.size() - 1 + return static_cast(len) >= buf.size() ? buf.size() - 1 : static_cast(len); } int8_t step_to_accuracy_decimals(float step) { diff --git a/esphome/core/helpers.h b/esphome/core/helpers.h index b575a14d14..769041160c 100644 --- a/esphome/core/helpers.h +++ b/esphome/core/helpers.h @@ -886,8 +886,15 @@ ParseOnOffState parse_on_off(const char *str, const char *on = nullptr, const ch /// Create a string from a value and an accuracy in decimals. std::string value_accuracy_to_string(float value, int8_t accuracy_decimals); -/// Create a string from a value, an accuracy in decimals, and a unit of measurement. -std::string value_accuracy_with_uom_to_string(float value, int8_t accuracy_decimals, StringRef unit_of_measurement); + +/// Maximum buffer size for value_accuracy formatting (float ~15 chars + space + UOM ~40 chars + null) +static constexpr size_t VALUE_ACCURACY_MAX_LEN = 64; + +/// Format value with accuracy to buffer, returns chars written (excluding null) +size_t value_accuracy_to_buf(std::span buf, float value, int8_t accuracy_decimals); +/// Format value with accuracy and UOM to buffer, returns chars written (excluding null) +size_t value_accuracy_with_uom_to_buf(std::span buf, float value, + int8_t accuracy_decimals, StringRef unit_of_measurement); /// Derive accuracy in decimals from an increment step. int8_t step_to_accuracy_decimals(float step);