RAMAllocatorH264< T > Class Template Reference

STL-compatible allocator that uses internal RAM (DRAM) allocation. More...

#include <RAMAllocatorH264.h>

Classes
struct	rebind
	Rebind allocator to different type. More...

Public Types
using	value_type = T
	The type of objects this allocator can allocate.

Public Member Functions
	RAMAllocatorH264 () noexcept
	Default constructor.
template<class U >
	RAMAllocatorH264 (const RAMAllocatorH264< U > &) noexcept
	Copy constructor from different allocator type.
T *	allocate (std::size_t n)
	Allocate memory for n objects of type T in internal RAM.
void	deallocate (T *p, std::size_t) noexcept
	Deallocate memory previously allocated by this allocator.

Detailed Description

template<typename T = uint8_t>
class esp_h264::RAMAllocatorH264< T >

STL-compatible allocator that uses internal RAM (DRAM) allocation.

RAMAllocatorH264 is a custom C++ allocator that allocates memory from internal DRAM using heap_caps_aligned_calloc with MALLOC_CAP_INTERNAL. This ensures allocation from fast internal memory rather than external PSRAM.

This allocator is useful for ESP32 platforms when you specifically want small, frequently-accessed buffers to be stored in fast internal RAM rather than slower external PSRAM.

Template Parameters

T	The type of objects to allocate

Note

On ESP-IDF platforms, uses heap_caps_aligned_calloc for internal RAM allocation

On Arduino platforms, the heap_caps functions are shimmed to standard malloc/free

Memory is zero-initialized (calloc behavior)

Provides proper alignment for the allocated type

Example usage:

#include "RAMAllocatorH264.h"
 
// Use with std::vector for small, fast buffers
std::vector<uint32_t, RAMAllocatorH264<uint32_t>> smallBuffer;
smallBuffer.resize(256);  // Small buffer in fast internal RAM
 
// Or use the convenience alias
RAMVec<uint32_t> fastBuffer;
fastBuffer.resize(256);

Member Typedef Documentation

value_type

using value_type = T

The type of objects this allocator can allocate.

Constructor & Destructor Documentation

RAMAllocatorH264() [1/2]

RAMAllocatorH264 ( )

inlinenoexcept

Default constructor.

Constructs a RAMAllocatorH264. No initialization needed.

RAMAllocatorH264() [2/2]

RAMAllocatorH264 ( const RAMAllocatorH264< U > &  )

inlinenoexcept

Copy constructor from different allocator type.

Allows construction from RAMAllocatorH264 of different type U. Required for STL allocator requirements.

Template Parameters

U	The type parameter of the source allocator

Parameters

other

Source allocator (unused)

Member Function Documentation

allocate()

T * allocate ( std::size_t  n )

inline

Allocate memory for n objects of type T in internal RAM.

Attempts to allocate memory in the following priority order:

1. Internal RAM using heap_caps_aligned_calloc (if available)
2. Aligned allocation using aligned_alloc (C11)
3. Standard calloc as fallback

All allocated memory is zero-initialized.

Parameters

n	Number of objects of type T to allocate

Returns

Pointer to allocated memory

Exceptions

std::bad_alloc

if allocation fails

Note

Memory is aligned by 16

On ESP32, prefers internal DRAM allocation over PSRAM

deallocate()

void deallocate ( T *  p, std::size_t    )

inlinenoexcept

Deallocate memory previously allocated by this allocator.

Frees memory that was allocated by allocate(). Uses heap_caps_free which works for both internal RAM and regular heap allocations.

Parameters

p	Pointer to memory to deallocate (can be nullptr)
n	Number of objects (ignored, but required by allocator interface)

Note

Safe to call with nullptr

The size parameter n is ignored as heap_caps_free doesn't need it

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

• src/RAMAllocatorH264.h