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[api] Extract inline varint encoders as named ALWAYS_INLINE helpers

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Move the inline varint byte writes into encode_varint_16_ and
encode_varint_8_ for readability. Same generated code since both
are ALWAYS_INLINE.
This commit is contained in:
J. Nick Koston
2026-04-01 22:47:13 -10:00
parent a8c6c55de2
commit 3ca5e9a3f5
1 changed files with 28 additions and 24 deletions
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esphome/components/api/api_frame_helper_plaintext.cpp
+28 -24
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@@ -237,6 +237,29 @@ ESPHOME_ALWAYS_INLINE static inline uint8_t varint_encoded_length_8(uint8_t valu
return value < ProtoSize::VARINT_THRESHOLD_1_BYTE ? 1 : 2;
}
// Encode a 16-bit varint (1-3 bytes) using pre-computed length.
ESPHOME_ALWAYS_INLINE static inline void encode_varint_16_(uint16_t value, uint8_t varint_len, uint8_t *p) {
if (varint_len >= 2) {
*p++ = static_cast<uint8_t>(value | 0x80);
value >>= 7;
if (varint_len == 3) {
*p++ = static_cast<uint8_t>(value | 0x80);
value >>= 7;
}
}
*p = static_cast<uint8_t>(value);
}
// Encode an 8-bit varint (1-2 bytes) using pre-computed length.
ESPHOME_ALWAYS_INLINE static inline void encode_varint_8_(uint8_t value, uint8_t varint_len, uint8_t *p) {
if (varint_len == 2) {
*p++ = static_cast<uint8_t>(value | 0x80);
*p = static_cast<uint8_t>(value >> 7);
} else {
*p = value;
}
}
// Compute plaintext header length: indicator (1) + size varint + type varint.
ESPHOME_ALWAYS_INLINE static inline uint8_t plaintext_header_length(const MessageInfo &msg) {
return 1 + varint_encoded_length_16(msg.payload_size) + varint_encoded_length_8(msg.message_type);
@@ -276,31 +299,12 @@ ESPHOME_ALWAYS_INLINE static inline uint8_t write_plaintext_header(uint8_t *buf_
// So we write the header starting at offset + HEADER_PADDING - total_header_len
uint32_t header_offset = APIPlaintextFrameHelper::HEADER_PADDING - total_header_len;
// Write the plaintext header with inline varint encoding.
// We already know the varint lengths so we can write the exact bytes directly
// without a generic loop, avoiding function call overhead.
uint8_t *p = buf_start + header_offset;
*p++ = 0x00; // indicator
// Write the plaintext header
buf_start[header_offset] = 0x00; // indicator
// Encode payload size varint (1-3 bytes)
uint16_t size_val = msg.payload_size;
if (size_varint_len >= 2) {
*p++ = static_cast<uint8_t>(size_val | 0x80);
size_val >>= 7;
if (size_varint_len == 3) {
*p++ = static_cast<uint8_t>(size_val | 0x80);
size_val >>= 7;
}
}
*p++ = static_cast<uint8_t>(size_val);
// Encode message type varint (1-2 bytes)
if (type_varint_len == 2) {
*p++ = static_cast<uint8_t>(msg.message_type | 0x80);
*p = static_cast<uint8_t>(msg.message_type >> 7);
} else {
*p = msg.message_type;
}
// Encode varints directly into buffer using pre-computed lengths
encode_varint_16_(msg.payload_size, size_varint_len, buf_start + header_offset + 1);
encode_varint_8_(msg.message_type, type_varint_len, buf_start + header_offset + 1 + size_varint_len);
return total_header_len;
}