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[api] Use integer comparison for float zero checks in protobuf encoding (#15490)

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This commit is contained in:
J. Nick Koston
2026-04-06 14:25:53 -10:00
committed by GitHub
parent 0816579fa9
commit b155c13117
1 changed files with 18 additions and 9 deletions
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27
esphome/components/api/proto.h
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@@ -25,6 +25,19 @@ constexpr uint8_t WIRE_TYPE_LENGTH_DELIMITED = 2; // string, bytes, embedded me
constexpr uint8_t WIRE_TYPE_FIXED32 = 5; // fixed32, sfixed32, float
constexpr uint8_t WIRE_TYPE_MASK = 0b111; // Mask to extract wire type from tag
// Reinterpret float bits as uint32_t without floating-point comparison.
// Used by both encode_float() and calc_float() to ensure identical zero checks.
// Uses union type-punning which is a GCC/Clang extension (not standard C++),
// but bit_cast/memcpy don't optimize to a no-op on xtensa-gcc (ESP8266).
inline uint32_t float_to_raw(float value) {
union {
float f;
uint32_t u;
} v;
v.f = value;
return v.u;
}
// Helper functions for ZigZag encoding/decoding
inline constexpr uint32_t encode_zigzag32(int32_t value) {
return (static_cast<uint32_t>(value) << 1) ^ (static_cast<uint32_t>(value >> 31));
@@ -432,14 +445,10 @@ class ProtoEncode {
// is needed in the future, the necessary encoding/decoding functions must be added.
static inline void encode_float(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id, float value,
bool force = false) {
if (value == 0.0f && !force)
uint32_t raw = float_to_raw(value);
if (raw == 0 && !force)
return;
union {
float value;
uint32_t raw;
} val{};
val.value = value;
encode_fixed32(pos PROTO_ENCODE_DEBUG_ARG, field_id, val.raw);
encode_fixed32(pos PROTO_ENCODE_DEBUG_ARG, field_id, raw);
}
static inline void encode_int32(uint8_t *__restrict__ &pos PROTO_ENCODE_DEBUG_PARAM, uint32_t field_id, int32_t value,
bool force = false) {
@@ -751,8 +760,8 @@ class ProtoSize {
}
static constexpr uint32_t calc_bool(uint32_t field_id_size, bool value) { return value ? field_id_size + 1 : 0; }
static constexpr uint32_t calc_bool_force(uint32_t field_id_size) { return field_id_size + 1; }
static constexpr uint32_t calc_float(uint32_t field_id_size, float value) {
return value != 0.0f ? field_id_size + 4 : 0;
static uint32_t calc_float(uint32_t field_id_size, float value) {
return float_to_raw(value) != 0 ? field_id_size + 4 : 0;
}
static constexpr uint32_t calc_fixed32(uint32_t field_id_size, uint32_t value) {
return value ? field_id_size + 4 : 0;