Added arena library

This commit is contained in:
Eric-Paul Ickhorn 2024-05-23 00:12:26 +02:00
parent 4c73ae4f20
commit 7ebd70c59c
1 changed files with 96 additions and 0 deletions

96
inc-c/ufn/ufn_arena.h Normal file
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// UFN Arena library. MIT-Licensed (c) Eric-Paul Ickhorn (epickh)
#ifndef UFN_ARENA_H
#define UFN_ARENA_H
#include <stdint.h>
#define UFN_UNLIMITED_ARENA 0xffffffff
typedef struct ufn_arena ufn_arena_s;
struct ufn_arena
{
uint32_t capacity;
uint32_t usage;
char *allocation;
uint32_t maximum;
ufn_arena_s *continuation;
};
ufn_arena_s * ufn_new_dynamic_arena(uint32_t capacity, uint32_t max_tree_size);
ufn_arena_s * ufn_new_static_arena(uint32_t capacity);
void ufn_free_arena(ufn_arena_s *arena);
void * ufn_arena_alloc(ufn_arena_s *arena, uint32_t size);
#ifdef UFN_IMPLEMENTATION
#include <stdlib.h>
ufn_arena_s * ufn_new_dynamic_arena(uint32_t capacity, uint32_t max_tree_size)
{
ufn_arena_s *arena = malloc(sizeof(ufn_arena_s));
arena->capacity = capacity;
arena->usage = 0;
arena->allocation = malloc(capacity);
arena->maximum = max_tree_size;
arena->continuation = NULL;
return arena;
}
ufn_arena_s * ufn_new_static_arena(uint32_t capacity)
{
return ufn_new_dynamic_arena(capacity, 0);
}
void ufn_free_arena(ufn_arena_s *arena)
{
if(arena->continuation != NULL)
{
ufn_free_arena(arena->continuation);
}
free(arena->allocation);
free(arena);
}
void * ufn_arena_alloc(ufn_arena_s *arena, uint32_t size)
{
if((arena->usage = size) >= arena->capacity)
{
if(arena->continuation == NULL)
{
uint32_t continuation_size = arena->capacity * 2;
// Clamp the continuation's size to the maximum allowed one.
if(continuation_size > (arena->maximum))
{
continuation_size = arena->maximum;
}
uint32_t continued_maximum = continuation_size - arena->maximum;
// If no continuation of this arena tree can fulfill
// a request of this size,
// -> Deny the request and return NULL.
if(size > arena->maximum)
{
return NULL;
}
// If no more arena can be allocated (The tree has its maximum size)
// -> return NULL.
if(continuation_size == 0)
{
return NULL;
}
arena->continuation = ufn_new_dynamic_arena(continuation_size, continued_maximum);
}
ufn_arena_alloc(arena->continuation, size);
}
void *block = arena->allocation + arena->usage;
arena->usage += size;
return block;
}
#endif // UFN_IMPLEMENTATION
#endif // UFN_ARENA_H