esphome::api::APIBuffer Class Reference

Byte buffer that skips zero-initialization on resize(). More...

#include <api_buffer.h>

Public Member Functions
void	clear ()
bool	reserve (size_t n) ESPHOME_ALWAYS_INLINE
	Returns false if allocation fails; the buffer is left unchanged.
bool	resize (size_t n) ESPHOME_ALWAYS_INLINE
	Returns false if allocation fails; the buffer is left unchanged. No zero-fill.
bool	reserve_and_resize (size_t reserve_size, size_t new_size) ESPHOME_ALWAYS_INLINE
	Reserve capacity for max(reserve_size, new_size) bytes, then set size to new_size.
uint8_t *	append (size_t n)
	Grow by n bytes; returns the new bytes, or nullptr on allocation failure.
void	drop_front (size_t drop)
	Drop the first drop bytes, sliding the rest down. Precondition: drop <= size().
uint8_t *	data ()
const uint8_t *	data () const
size_t	size () const
size_t	capacity () const
bool	empty () const
uint8_t &	operator[] (size_t i)
const uint8_t &	operator[] (size_t i) const
void	release ()
	Release all memory (equivalent to std::vector swap trick).

Static Public Attributes
static constexpr size_t	MAX_SIZE = UINT16_MAX

Protected Member Functions
bool	grow_ (size_t n)
void	debug_check_drop_ (size_t drop) const

Protected Attributes
RAMUniquePtr< uint8_t[]>	data_
uint16_t	size_ {0}
uint16_t	capacity_ {0}

Detailed Description

Byte buffer that skips zero-initialization on resize().

std::vector<uint8_t>::resize() zero-fills new bytes via memset. For the shared protobuf write buffer, every byte is overwritten by the encoder, making the zero-fill pure waste. For the receive buffer, bytes are overwritten by socket reads.

Designed for bulk clear/resize/overwrite patterns. grow_() allocates exactly the requested size (no growth factor) since callers resize to known sizes rather than appending incrementally.

Safe because: callers always write exactly the number of bytes they resize for. In the protobuf write path, debug_check_bounds_ validates writes in debug builds.

Definition at line 26 of file api_buffer.h.

Member Function Documentation

append()

uint8_t * esphome::api::APIBuffer::append ( size_t n )

nodiscard

Grow by n bytes; returns the new bytes, or nullptr on allocation failure.

Definition at line 30 of file api_buffer.cpp.

capacity()

size_t esphome::api::APIBuffer::capacity ( ) const

inline

Definition at line 56 of file api_buffer.h.

clear()

void esphome::api::APIBuffer::clear ( )

inline

Definition at line 29 of file api_buffer.h.

data() [1/2]

uint8_t * esphome::api::APIBuffer::data ( )

inline

Definition at line 53 of file api_buffer.h.

data() [2/2]

const uint8_t * esphome::api::APIBuffer::data ( ) const

inline

Definition at line 54 of file api_buffer.h.

debug_check_drop_()

void esphome::api::APIBuffer::debug_check_drop_ ( size_t drop ) const

protected

Definition at line 9 of file api_buffer.cpp.

drop_front()

void esphome::api::APIBuffer::drop_front ( size_t drop )

inline

Drop the first drop bytes, sliding the rest down. Precondition: drop <= size().

Definition at line 46 of file api_buffer.h.

empty()

bool esphome::api::APIBuffer::empty ( ) const

inline

Definition at line 57 of file api_buffer.h.

grow_()

bool esphome::api::APIBuffer::grow_ ( size_t n )

protected

Definition at line 17 of file api_buffer.cpp.

operator[]() [1/2]

uint8_t & esphome::api::APIBuffer::operator[] ( size_t i )

inline

Definition at line 58 of file api_buffer.h.

operator[]() [2/2]

const uint8_t & esphome::api::APIBuffer::operator[] ( size_t i ) const

inline

Definition at line 59 of file api_buffer.h.

release()

void esphome::api::APIBuffer::release ( )

inline

Release all memory (equivalent to std::vector swap trick).

Definition at line 61 of file api_buffer.h.

reserve()

bool esphome::api::APIBuffer::reserve ( size_t n )

inlinenodiscard

Returns false if allocation fails; the buffer is left unchanged.

Definition at line 31 of file api_buffer.h.

reserve_and_resize()

bool esphome::api::APIBuffer::reserve_and_resize ( size_t reserve_size, size_t new_size )

inlinenodiscard

Reserve capacity for max(reserve_size, new_size) bytes, then set size to new_size.

Single grow_ check regardless of argument order. Returns false if allocation fails; the buffer is left unchanged.

Definition at line 37 of file api_buffer.h.

resize()

bool esphome::api::APIBuffer::resize ( size_t n )

inlinenodiscard

Returns false if allocation fails; the buffer is left unchanged. No zero-fill.

Definition at line 33 of file api_buffer.h.

size()

size_t esphome::api::APIBuffer::size ( ) const

inline

Definition at line 55 of file api_buffer.h.

Field Documentation

capacity_

uint16_t esphome::api::APIBuffer::capacity_ {0}

protected

Definition at line 76 of file api_buffer.h.

data_

RAMUniquePtr<uint8_t[]> esphome::api::APIBuffer::data_

protected

Definition at line 74 of file api_buffer.h.

MAX_SIZE

size_t esphome::api::APIBuffer::MAX_SIZE = UINT16_MAX

staticconstexpr

Definition at line 28 of file api_buffer.h.

size_

uint16_t esphome::api::APIBuffer::size_ {0}

protected

Definition at line 75 of file api_buffer.h.

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The documentation for this class was generated from the following files:

• esphome/components/api/api_buffer.h
• esphome/components/api/api_buffer.cpp