Detalloc — Phase 1: Single-Pool, Constant-Time Allocator. More...

#include <stdbool.h>
#include <stddef.h>
#include <stdint.h>

Include dependency graph for detalloc.h:

This graph shows which files directly or indirectly include this file:

Data Structures
struct	det_config_t
	Phase-1 configuration: one fixed-size pool. More...

Macros
#define	DETALLOC_VERSION_MAJOR 0

#define	DETALLOC_VERSION_MINOR 1

#define	DETALLOC_VERSION_PATCH 0

#define	DET_ALIGN_UP(sz, a) (((sz) + ((a)-1)) & ~((a)-1))

#define	DET_NEW(alloc, type) ((type *)det_alloc((alloc)))

#define	DET_FREE(alloc, ptr)

Typedefs
typedef struct det_allocator	det_allocator_t
	Opaque allocator handle (single pool in Phase 1).

Enumerations
enum	det_error_t { DET_OK = 0 , DET_ERR_INVALID_PARAM , DET_ERR_OUT_OF_MEMORY , DET_ERR_POOL_FULL , DET_ERR_INVALID_PTR , DET_ERR_NOT_INITIALIZED }
	Error/status codes returned by Detalloc. More...

Functions
DETALLOC_API size_t	det_alloc_size (const det_config_t *config)
	Compute required buffer size for a given Phase-1 config.

DETALLOC_API det_allocator_t *	det_alloc_init (void memory, size_t size, const det_config_t config)
	Initialize allocator over a user-provided memory buffer.

DETALLOC_API void *	det_alloc (det_allocator_t *alloc)
	Allocate a single fixed-size block.

DETALLOC_API void *	det_calloc (det_allocator_t *alloc)
	Allocate a zero-initialized block.

DETALLOC_API void	det_free (det_allocator_t alloc, void ptr)
	Free a previously allocated block (NULL is a no-op).

DETALLOC_API size_t	det_alloc_usable_size (det_allocator_t alloc, void ptr)
	Return usable size of a block.

DETALLOC_API void	det_alloc_destroy (det_allocator_t *alloc)
	Destroy allocator structures (metadata cleanup only).

DETALLOC_API det_config_t	det_default_config (void)
	Return a sensible Phase-1 default config.

DETALLOC_API const char *	det_version_string (void)
	Get library version string "major.minor.patch".

Detailed Description

Detalloc — Phase 1: Single-Pool, Constant-Time Allocator.

Minimal API for a fixed-size, bitmap-based pool allocator with O(1) alloc/free. Designed for hard real-time use; no syscalls after init; uses user-provided memory.

Version: 0.1.0

Date: 2025

Definition in file detalloc.h.

Macro Definition Documentation

◆ DET_ALIGN_UP

#define DET_ALIGN_UP	(	sz,
		a
	)	(((sz) + ((a)-1)) & ~((a)-1))

Default block size for Phase 1 (can be overridden at init-time). Default alignment for returned blocks (power of two). Align up helper.

Definition at line 80 of file detalloc.h.

◆ DET_FREE

#define DET_FREE	(	alloc,
		ptr
	)

Value:

  do {                                                                         \
    det_free((alloc), (ptr));                                                  \
    (ptr) = NULL;                                                              \
  } while (0)

Free and null a pointer.

Definition at line 243 of file detalloc.h.

◆ DET_NEW

#define DET_NEW	(	alloc,
		type
	)	((type *)det_alloc((alloc)))

Allocate a typed object (one fixed-size block must fit it).

Definition at line 240 of file detalloc.h.

◆ DETALLOC_VERSION_MAJOR

#define DETALLOC_VERSION_MAJOR 0

Definition at line 61 of file detalloc.h.

◆ DETALLOC_VERSION_MINOR

#define DETALLOC_VERSION_MINOR 1

Definition at line 62 of file detalloc.h.

◆ DETALLOC_VERSION_PATCH

#define DETALLOC_VERSION_PATCH 0

Definition at line 63 of file detalloc.h.

Typedef Documentation

◆ det_allocator_t

typedef struct det_allocator det_allocator_t

Opaque allocator handle (single pool in Phase 1).

Implementation maintains:

user buffer base/limit
bitmap for free/used slots
fixed block size & count
optional lock if thread_safe=true

Definition at line 110 of file detalloc.h.

Enumeration Type Documentation

◆ det_error_t

enum det_error_t

Error/status codes returned by Detalloc.

Enumerator
DET_OK	Operation successful
DET_ERR_INVALID_PARAM	A parameter is invalid
DET_ERR_OUT_OF_MEMORY	Buffer cannot accommodate configuration
DET_ERR_POOL_FULL	Pool has no free blocks
DET_ERR_INVALID_PTR	Pointer not owned by allocator/pool
DET_ERR_NOT_INITIALIZED	Allocator not initialized

Definition at line 89 of file detalloc.h.

Function Documentation

◆ det_alloc()

DETALLOC_API void * det_alloc ( det_allocator_t * alloc )

Allocate a single fixed-size block.

Parameters

alloc Allocator handle

Returns: Pointer to block on success, or NULL if pool is full

Note: Returned pointer is aligned to config.align.

Complexity: O(1) worst-case.

◆ det_alloc_destroy()

DETALLOC_API void det_alloc_destroy ( det_allocator_t * alloc )

Destroy allocator structures (metadata cleanup only).

The user-provided memory buffer is not freed.

Parameters

alloc Allocator handle

Complexity: O(1).

◆ det_alloc_init()

DETALLOC_API det_allocator_t * det_alloc_init	(	void *	memory,
		size_t	size,
		const det_config_t *	config
	)

Initialize allocator over a user-provided memory buffer.

No dynamic allocation; all metadata lives inside memory.

Parameters

memory	Pointer to pre-allocated memory buffer (non-NULL)
size	Size of memory buffer in bytes (>= det_alloc_size(config))
config	Non-NULL Phase-1 configuration

Returns: Allocator handle on success, or NULL on error

Note: The buffer must remain valid for the allocator lifetime.

Complexity: O(1).

◆ det_alloc_size()

DETALLOC_API size_t det_alloc_size ( const det_config_t * config )

Compute required buffer size for a given Phase-1 config.

Calculates metadata + bitmap + aligned payload area.

Parameters

config Non-NULL configuration

Returns: Required bytes, or 0 on error

Complexity: O(1).

◆ det_alloc_usable_size()

DETALLOC_API size_t det_alloc_usable_size	(	det_allocator_t *	alloc,
		void *	ptr
	)

Return usable size of a block.

Parameters

alloc	Allocator handle
ptr	Pointer to allocated block

Returns: Fixed block size (or 0 if invalid)

Complexity: O(1).

◆ det_calloc()

DETALLOC_API void * det_calloc ( det_allocator_t * alloc )

Allocate a zero-initialized block.

Parameters

alloc Allocator handle

Returns: Pointer to zeroed block, or NULL if pool is full

Complexity: O(block_size) for zeroing, O(1) for allocation.

◆ det_default_config()

DETALLOC_API det_config_t det_default_config ( void )

Return a sensible Phase-1 default config.

Defaults:

block_size = DET_DEFAULT_BLOCK_SIZE
num_blocks = 0 (must be set by user)
align = DET_DEFAULT_ALIGN
thread_safe = false

Definition at line 5 of file detalloc.c.

References det_config_t::align, det_config_t::block_size, det_config_t::num_blocks, and det_config_t::thread_safe.

◆ det_free()

DETALLOC_API void det_free	(	det_allocator_t *	alloc,
		void *	ptr
	)

Free a previously allocated block (NULL is a no-op).

Parameters

alloc	Allocator handle
ptr	Pointer returned by det_alloc()/det_calloc()

Warning: Undefined behavior if ptr was not allocated by this allocator.

Complexity: O(1) worst-case.

◆ det_version_string()

DETALLOC_API const char * det_version_string ( void )

Get library version string "major.minor.patch".

Definition at line 3 of file detalloc.c.

Data Structures

Macros

Typedefs

Enumerations

Functions

Detailed Description

Macro Definition Documentation

◆ DET_ALIGN_UP

◆ DET_FREE

◆ DET_NEW

◆ DETALLOC_VERSION_MAJOR

◆ DETALLOC_VERSION_MINOR

◆ DETALLOC_VERSION_PATCH

Typedef Documentation

◆ det_allocator_t

Enumeration Type Documentation

◆ det_error_t

Function Documentation

◆ det_alloc()

◆ det_alloc_destroy()

◆ det_alloc_init()

◆ det_alloc_size()

◆ det_alloc_usable_size()

◆ det_calloc()

◆ det_default_config()

◆ det_free()

◆ det_version_string()