[light] Use bitmask instead of std::set for color modes (#11348)

esphome/components/light/color_mode.h

@@ -104,5 +104,200 @@ constexpr ColorModeHelper operator|(ColorModeHelper lhs, ColorMode rhs) {
   return static_cast<ColorMode>(static_cast<uint8_t>(lhs) | static_cast<uint8_t>(rhs));
 }
 
+// Type alias for raw color mode bitmask values
+using color_mode_bitmask_t = uint16_t;
+
+// Constants for ColorMode count and bit range
+static constexpr int COLOR_MODE_COUNT = 10;                             // UNKNOWN through RGB_COLD_WARM_WHITE
+static constexpr int MAX_BIT_INDEX = sizeof(color_mode_bitmask_t) * 8;  // Number of bits in bitmask type
+
+// Compile-time array of all ColorMode values in declaration order
+// Bit positions (0-9) map directly to enum declaration order
+static constexpr ColorMode COLOR_MODES[COLOR_MODE_COUNT] = {
+    ColorMode::UNKNOWN,                // bit 0
+    ColorMode::ON_OFF,                 // bit 1
+    ColorMode::BRIGHTNESS,             // bit 2
+    ColorMode::WHITE,                  // bit 3
+    ColorMode::COLOR_TEMPERATURE,      // bit 4
+    ColorMode::COLD_WARM_WHITE,        // bit 5
+    ColorMode::RGB,                    // bit 6
+    ColorMode::RGB_WHITE,              // bit 7
+    ColorMode::RGB_COLOR_TEMPERATURE,  // bit 8
+    ColorMode::RGB_COLD_WARM_WHITE,    // bit 9
+};
+
+/// Map ColorMode enum values to bit positions (0-9)
+/// Bit positions follow the enum declaration order
+static constexpr int mode_to_bit(ColorMode mode) {
+  // Linear search through COLOR_MODES array
+  // Compiler optimizes this to efficient code since array is constexpr
+  for (int i = 0; i < COLOR_MODE_COUNT; ++i) {
+    if (COLOR_MODES[i] == mode)
+      return i;
+  }
+  return 0;
+}
+
+/// Map bit positions (0-9) to ColorMode enum values
+/// Bit positions follow the enum declaration order
+static constexpr ColorMode bit_to_mode(int bit) {
+  // Direct lookup in COLOR_MODES array
+  return (bit >= 0 && bit < COLOR_MODE_COUNT) ? COLOR_MODES[bit] : ColorMode::UNKNOWN;
+}
+
+/// Helper to compute capability bitmask at compile time
+static constexpr color_mode_bitmask_t compute_capability_bitmask(ColorCapability capability) {
+  color_mode_bitmask_t mask = 0;
+  uint8_t cap_bit = static_cast<uint8_t>(capability);
+
+  // Check each ColorMode to see if it has this capability
+  for (int bit = 0; bit < COLOR_MODE_COUNT; ++bit) {
+    uint8_t mode_val = static_cast<uint8_t>(bit_to_mode(bit));
+    if ((mode_val & cap_bit) != 0) {
+      mask |= (1 << bit);
+    }
+  }
+  return mask;
+}
+
+// Number of ColorCapability enum values
+static constexpr int COLOR_CAPABILITY_COUNT = 6;
+
+/// Compile-time lookup table mapping ColorCapability to bitmask
+/// This array is computed at compile time using constexpr
+static constexpr color_mode_bitmask_t CAPABILITY_BITMASKS[] = {
+    compute_capability_bitmask(ColorCapability::ON_OFF),             // 1 << 0
+    compute_capability_bitmask(ColorCapability::BRIGHTNESS),         // 1 << 1
+    compute_capability_bitmask(ColorCapability::WHITE),              // 1 << 2
+    compute_capability_bitmask(ColorCapability::COLOR_TEMPERATURE),  // 1 << 3
+    compute_capability_bitmask(ColorCapability::COLD_WARM_WHITE),    // 1 << 4
+    compute_capability_bitmask(ColorCapability::RGB),                // 1 << 5
+};
+
+/// Bitmask for storing a set of ColorMode values efficiently.
+/// Replaces std::set<ColorMode> to eliminate red-black tree overhead (~586 bytes).
+class ColorModeMask {
+ public:
+  constexpr ColorModeMask() = default;
+
+  /// Support initializer list syntax: {ColorMode::RGB, ColorMode::WHITE}
+  constexpr ColorModeMask(std::initializer_list<ColorMode> modes) {
+    for (auto mode : modes) {
+      this->add(mode);
+    }
+  }
+
+  constexpr void add(ColorMode mode) { this->mask_ |= (1 << mode_to_bit(mode)); }
+
+  /// Add multiple modes at once using initializer list
+  constexpr void add(std::initializer_list<ColorMode> modes) {
+    for (auto mode : modes) {
+      this->add(mode);
+    }
+  }
+
+  constexpr bool contains(ColorMode mode) const { return (this->mask_ & (1 << mode_to_bit(mode))) != 0; }
+
+  constexpr size_t size() const {
+    // Count set bits using Brian Kernighan's algorithm
+    // More efficient for sparse bitmasks (typical case: 2-4 modes out of 10)
+    uint16_t n = this->mask_;
+    size_t count = 0;
+    while (n) {
+      n &= n - 1;  // Clear the least significant set bit
+      count++;
+    }
+    return count;
+  }
+
+  constexpr bool empty() const { return this->mask_ == 0; }
+
+  /// Iterator support for API encoding
+  class Iterator {
+   public:
+    using iterator_category = std::forward_iterator_tag;
+    using value_type = ColorMode;
+    using difference_type = std::ptrdiff_t;
+    using pointer = const ColorMode *;
+    using reference = ColorMode;
+
+    constexpr Iterator(color_mode_bitmask_t mask, int bit) : mask_(mask), bit_(bit) { advance_to_next_set_bit_(); }
+
+    constexpr ColorMode operator*() const { return bit_to_mode(bit_); }
+
+    constexpr Iterator &operator++() {
+      ++bit_;
+      advance_to_next_set_bit_();
+      return *this;
+    }
+
+    constexpr bool operator==(const Iterator &other) const { return bit_ == other.bit_; }
+
+    constexpr bool operator!=(const Iterator &other) const { return !(*this == other); }
+
+   private:
+    constexpr void advance_to_next_set_bit_() { bit_ = ColorModeMask::find_next_set_bit(mask_, bit_); }
+
+    color_mode_bitmask_t mask_;
+    int bit_;
+  };
+
+  constexpr Iterator begin() const { return Iterator(mask_, 0); }
+  constexpr Iterator end() const { return Iterator(mask_, MAX_BIT_INDEX); }
+
+  /// Get the raw bitmask value for API encoding
+  constexpr color_mode_bitmask_t get_mask() const { return this->mask_; }
+
+  /// Find the next set bit in a bitmask starting from a given position
+  /// Returns the bit position, or MAX_BIT_INDEX if no more bits are set
+  static constexpr int find_next_set_bit(color_mode_bitmask_t mask, int start_bit) {
+    int bit = start_bit;
+    while (bit < MAX_BIT_INDEX && !(mask & (1 << bit))) {
+      ++bit;
+    }
+    return bit;
+  }
+
+  /// Find the first set bit in a bitmask and return the corresponding ColorMode
+  /// Used for optimizing compute_color_mode_() intersection logic
+  static constexpr ColorMode first_mode_from_mask(color_mode_bitmask_t mask) {
+    return bit_to_mode(find_next_set_bit(mask, 0));
+  }
+
+  /// Check if a ColorMode is present in a raw bitmask value
+  /// Useful for checking intersection results without creating a temporary ColorModeMask
+  static constexpr bool mask_contains(color_mode_bitmask_t mask, ColorMode mode) {
+    return (mask & (1 << mode_to_bit(mode))) != 0;
+  }
+
+  /// Check if any mode in the bitmask has a specific capability
+  /// Used for checking if a light supports a capability (e.g., BRIGHTNESS, RGB)
+  bool has_capability(ColorCapability capability) const {
+    // Lookup the pre-computed bitmask for this capability and check intersection with our mask
+    // ColorCapability values: 1, 2, 4, 8, 16, 32 -> array indices: 0, 1, 2, 3, 4, 5
+    // We need to convert the power-of-2 value to an index
+    uint8_t cap_val = static_cast<uint8_t>(capability);
+#if defined(__GNUC__) || defined(__clang__)
+    // Use compiler intrinsic for efficient bit position lookup (O(1) vs O(log n))
+    int index = __builtin_ctz(cap_val);
+#else
+    // Fallback for compilers without __builtin_ctz
+    int index = 0;
+    while (cap_val > 1) {
+      cap_val >>= 1;
+      ++index;
+    }
+#endif
+    return (this->mask_ & CAPABILITY_BITMASKS[index]) != 0;
+  }
+
+ private:
+  // Using uint16_t instead of uint32_t for more efficient iteration (fewer bits to scan).
+  // Currently only 10 ColorMode values exist, so 16 bits is sufficient.
+  // Can be changed to uint32_t if more than 16 color modes are needed in the future.
+  // Note: Due to struct padding, uint16_t and uint32_t result in same LightTraits size (12 bytes).
+  color_mode_bitmask_t mask_{0};
+};
+
 }  // namespace light
 }  // namespace esphome

esphome/components/light/light_call.cpp

@@ -406,7 +406,7 @@ void LightCall::transform_parameters_() {
   }
 }
 ColorMode LightCall::compute_color_mode_() {
-  auto supported_modes = this->parent_->get_traits().get_supported_color_modes();
+  const auto &supported_modes = this->parent_->get_traits().get_supported_color_modes();
   int supported_count = supported_modes.size();
 
   // Some lights don't support any color modes (e.g. monochromatic light), leave it at unknown.
@@ -425,20 +425,19 @@ ColorMode LightCall::compute_color_mode_() {
   // If no color mode is specified, we try to guess the color mode. This is needed for backward compatibility to
   // pre-colormode clients and automations, but also for the MQTT API, where HA doesn't let us know which color mode
   // was used for some reason.
-  std::set<ColorMode> suitable_modes = this->get_suitable_color_modes_();
+  // Compute intersection of suitable and supported modes using bitwise AND
+  color_mode_bitmask_t intersection = this->get_suitable_color_modes_mask_() & supported_modes.get_mask();
 
-  // Don't change if the current mode is suitable.
-  if (suitable_modes.count(current_mode) > 0) {
+  // Don't change if the current mode is in the intersection (suitable AND supported)
+  if (ColorModeMask::mask_contains(intersection, current_mode)) {
     ESP_LOGI(TAG, "'%s': color mode not specified; retaining %s", this->parent_->get_name().c_str(),
              LOG_STR_ARG(color_mode_to_human(current_mode)));
     return current_mode;
   }
 
   // Use the preferred suitable mode.
-  for (auto mode : suitable_modes) {
-    if (supported_modes.count(mode) == 0)
-      continue;
-
+  if (intersection != 0) {
+    ColorMode mode = ColorModeMask::first_mode_from_mask(intersection);
     ESP_LOGI(TAG, "'%s': color mode not specified; using %s", this->parent_->get_name().c_str(),
              LOG_STR_ARG(color_mode_to_human(mode)));
     return mode;
@@ -451,7 +450,7 @@ ColorMode LightCall::compute_color_mode_() {
            LOG_STR_ARG(color_mode_to_human(color_mode)));
   return color_mode;
 }
-std::set<ColorMode> LightCall::get_suitable_color_modes_() {
+color_mode_bitmask_t LightCall::get_suitable_color_modes_mask_() {
   bool has_white = this->has_white() && this->white_ > 0.0f;
   bool has_ct = this->has_color_temperature();
   bool has_cwww =
@@ -459,36 +458,44 @@ std::set<ColorMode> LightCall::get_suitable_color_modes_() {
   bool has_rgb = (this->has_color_brightness() && this->color_brightness_ > 0.0f) ||
                  (this->has_red() || this->has_green() || this->has_blue());
 
-// Build key from flags: [rgb][cwww][ct][white]
+  // Build key from flags: [rgb][cwww][ct][white]
 #define KEY(white, ct, cwww, rgb) ((white) << 0 | (ct) << 1 | (cwww) << 2 | (rgb) << 3)
 
   uint8_t key = KEY(has_white, has_ct, has_cwww, has_rgb);
 
   switch (key) {
     case KEY(true, false, false, false):  // white only
-      return {ColorMode::WHITE, ColorMode::RGB_WHITE, ColorMode::RGB_COLOR_TEMPERATURE, ColorMode::COLD_WARM_WHITE,
-              ColorMode::RGB_COLD_WARM_WHITE};
+      return ColorModeMask({ColorMode::WHITE, ColorMode::RGB_WHITE, ColorMode::RGB_COLOR_TEMPERATURE,
+                            ColorMode::COLD_WARM_WHITE, ColorMode::RGB_COLD_WARM_WHITE})
+          .get_mask();
     case KEY(false, true, false, false):  // ct only
-      return {ColorMode::COLOR_TEMPERATURE, ColorMode::RGB_COLOR_TEMPERATURE, ColorMode::COLD_WARM_WHITE,
-              ColorMode::RGB_COLD_WARM_WHITE};
+      return ColorModeMask({ColorMode::COLOR_TEMPERATURE, ColorMode::RGB_COLOR_TEMPERATURE, ColorMode::COLD_WARM_WHITE,
+                            ColorMode::RGB_COLD_WARM_WHITE})
+          .get_mask();
     case KEY(true, true, false, false):  // white + ct
-      return {ColorMode::COLD_WARM_WHITE, ColorMode::RGB_COLOR_TEMPERATURE, ColorMode::RGB_COLD_WARM_WHITE};
+      return ColorModeMask(
+                 {ColorMode::COLD_WARM_WHITE, ColorMode::RGB_COLOR_TEMPERATURE, ColorMode::RGB_COLD_WARM_WHITE})
+          .get_mask();
     case KEY(false, false, true, false):  // cwww only
-      return {ColorMode::COLD_WARM_WHITE, ColorMode::RGB_COLD_WARM_WHITE};
+      return ColorModeMask({ColorMode::COLD_WARM_WHITE, ColorMode::RGB_COLD_WARM_WHITE}).get_mask();
     case KEY(false, false, false, false):  // none
-      return {ColorMode::RGB_WHITE, ColorMode::RGB_COLOR_TEMPERATURE, ColorMode::RGB_COLD_WARM_WHITE, ColorMode::RGB,
-              ColorMode::WHITE,     ColorMode::COLOR_TEMPERATURE,     ColorMode::COLD_WARM_WHITE};
+      return ColorModeMask({ColorMode::RGB_WHITE, ColorMode::RGB_COLOR_TEMPERATURE, ColorMode::RGB_COLD_WARM_WHITE,
+                            ColorMode::RGB, ColorMode::WHITE, ColorMode::COLOR_TEMPERATURE, ColorMode::COLD_WARM_WHITE})
+          .get_mask();
     case KEY(true, false, false, true):  // rgb + white
-      return {ColorMode::RGB_WHITE, ColorMode::RGB_COLOR_TEMPERATURE, ColorMode::RGB_COLD_WARM_WHITE};
+      return ColorModeMask({ColorMode::RGB_WHITE, ColorMode::RGB_COLOR_TEMPERATURE, ColorMode::RGB_COLD_WARM_WHITE})
+          .get_mask();
     case KEY(false, true, false, true):  // rgb + ct
     case KEY(true, true, false, true):   // rgb + white + ct
-      return {ColorMode::RGB_COLOR_TEMPERATURE, ColorMode::RGB_COLD_WARM_WHITE};
+      return ColorModeMask({ColorMode::RGB_COLOR_TEMPERATURE, ColorMode::RGB_COLD_WARM_WHITE}).get_mask();
     case KEY(false, false, true, true):  // rgb + cwww
-      return {ColorMode::RGB_COLD_WARM_WHITE};
+      return ColorModeMask({ColorMode::RGB_COLD_WARM_WHITE}).get_mask();
     case KEY(false, false, false, true):  // rgb only
-      return {ColorMode::RGB, ColorMode::RGB_WHITE, ColorMode::RGB_COLOR_TEMPERATURE, ColorMode::RGB_COLD_WARM_WHITE};
+      return ColorModeMask({ColorMode::RGB, ColorMode::RGB_WHITE, ColorMode::RGB_COLOR_TEMPERATURE,
+                            ColorMode::RGB_COLD_WARM_WHITE})
+          .get_mask();
     default:
-      return {};  // conflicting flags
+      return 0;  // conflicting flags
   }
 
 #undef KEY

esphome/components/light/light_call.h

@@ -1,7 +1,6 @@
 #pragma once
 
 #include "light_color_values.h"
-#include <set>
 
 namespace esphome {
 
@@ -186,8 +185,8 @@ class LightCall {
 
   //// Compute the color mode that should be used for this call.
   ColorMode compute_color_mode_();
-  /// Get potential color modes for this light call.
-  std::set<ColorMode> get_suitable_color_modes_();
+  /// Get potential color modes bitmask for this light call.
+  color_mode_bitmask_t get_suitable_color_modes_mask_();
   /// Some color modes also can be set using non-native parameters, transform those calls.
   void transform_parameters_();
 

esphome/components/light/light_json_schema.cpp

@@ -43,7 +43,6 @@ void LightJSONSchema::dump_json(LightState &state, JsonObject root) {
   }
 
   auto values = state.remote_values;
-  auto traits = state.get_output()->get_traits();
 
   const auto color_mode = values.get_color_mode();
   const char *mode_str = get_color_mode_json_str(color_mode);

esphome/components/light/light_state.cpp

@@ -191,11 +191,9 @@ void LightState::current_values_as_brightness(float *brightness) {
   this->current_values.as_brightness(brightness, this->gamma_correct_);
 }
 void LightState::current_values_as_rgb(float *red, float *green, float *blue, bool color_interlock) {
-  auto traits = this->get_traits();
   this->current_values.as_rgb(red, green, blue, this->gamma_correct_, false);
 }
 void LightState::current_values_as_rgbw(float *red, float *green, float *blue, float *white, bool color_interlock) {
-  auto traits = this->get_traits();
   this->current_values.as_rgbw(red, green, blue, white, this->gamma_correct_, false);
 }
 void LightState::current_values_as_rgbww(float *red, float *green, float *blue, float *cold_white, float *warm_white,
@@ -209,7 +207,6 @@ void LightState::current_values_as_rgbct(float *red, float *green, float *blue,
                                 white_brightness, this->gamma_correct_);
 }
 void LightState::current_values_as_cwww(float *cold_white, float *warm_white, bool constant_brightness) {
-  auto traits = this->get_traits();
   this->current_values.as_cwww(cold_white, warm_white, this->gamma_correct_, constant_brightness);
 }
 void LightState::current_values_as_ct(float *color_temperature, float *white_brightness) {

esphome/components/light/light_traits.h

@@ -2,7 +2,6 @@
 
 #include "esphome/core/helpers.h"
 #include "color_mode.h"
-#include <set>
 
 namespace esphome {
 
@@ -19,18 +18,17 @@ class LightTraits {
  public:
   LightTraits() = default;
 
-  const std::set<ColorMode> &get_supported_color_modes() const { return this->supported_color_modes_; }
-  void set_supported_color_modes(std::set<ColorMode> supported_color_modes) {
-    this->supported_color_modes_ = std::move(supported_color_modes);
+  const ColorModeMask &get_supported_color_modes() const { return this->supported_color_modes_; }
+  void set_supported_color_modes(ColorModeMask supported_color_modes) {
+    this->supported_color_modes_ = supported_color_modes;
+  }
+  void set_supported_color_modes(std::initializer_list<ColorMode> modes) {
+    this->supported_color_modes_ = ColorModeMask(modes);
   }
 
-  bool supports_color_mode(ColorMode color_mode) const { return this->supported_color_modes_.count(color_mode); }
+  bool supports_color_mode(ColorMode color_mode) const { return this->supported_color_modes_.contains(color_mode); }
   bool supports_color_capability(ColorCapability color_capability) const {
-    for (auto mode : this->supported_color_modes_) {
-      if (mode & color_capability)
-        return true;
-    }
-    return false;
+    return this->supported_color_modes_.has_capability(color_capability);
   }
 
   ESPDEPRECATED("get_supports_brightness() is deprecated, use color modes instead.", "v1.21")
@@ -59,19 +57,9 @@ class LightTraits {
   void set_max_mireds(float max_mireds) { this->max_mireds_ = max_mireds; }
 
  protected:
-#ifdef USE_API
-  // The API connection is a friend class to access internal methods
-  friend class api::APIConnection;
-  // This method returns a reference to the internal color modes set.
-  // It is used by the API to avoid copying data when encoding messages.
-  // Warning: Do not use this method outside of the API connection code.
-  // It returns a reference to internal data that can be invalidated.
-  const std::set<ColorMode> &get_supported_color_modes_for_api_() const { return this->supported_color_modes_; }
-#endif
-
-  std::set<ColorMode> supported_color_modes_{};
   float min_mireds_{0};
   float max_mireds_{0};
+  ColorModeMask supported_color_modes_{};
 };
 
 }  // namespace light