Kaltenberg/modules/utility/src-c/allocation/arena.c

#include <voxula/internals/utility/allocation.h>
#include <voxula/internals/utility/math.h>
#include <voxula/internals/utility/containers.h>

#include <stdlib.h>
#include <string.h>

vx_arena_s * vx_new_arena(uint32_t capacity)
{
    vx_arena_s *arena = malloc(vx_ceil_to(sizeof(vx_arena_s), 32) + capacity);
    arena->usage = 0;
    arena->capacity = capacity;
    arena->allocation = (void *) ((int8_t *) arena) + 32;
    arena->continuation = NULL;
    return arena;
}

void vx_free_arena(vx_arena_s *arena)
{
    if(arena->continuation)
    {
        vx_free_arena(arena->continuation);
    }
    free(arena);
}

void * vx_arena_alloc(vx_arena_s *arena, uint32_t length)
{
    if((arena->usage + length) >= arena->capacity)
    {
        if( ! arena->continuation)
        {
            arena->continuation = vx_new_arena(vx_max_u64(arena->capacity * 2, length * 2));
        }
        return vx_arena_alloc(arena->continuation, length);
    }
    void *allocation = (uint8_t *) arena->allocation + arena->usage;
    arena->usage += length;
    return allocation;
}

char * vx_arena_dupe_string(vx_arena_s *arena, const char *string)
{
    uint32_t len_string = strlen(string);
    char *string_duplicate = vx_arena_alloc(arena, len_string + 1);
    memcpy(string_duplicate, string, len_string);
    return string_duplicate;
}

char * vx_arena_dupe_string_up_to(vx_arena_s *arena, const char *string, uint32_t maximum)
{
    uint32_t length = vx_measure_string_up_to(string, maximum);
    char *string_duplicate = vx_arena_alloc(arena, length + 1);
    memcpy(string_duplicate, string, length);
    string_duplicate[length] = 0;
    return string_duplicate;
}