arena.c


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#include "arena.h"
#include "macros.h"
#include "sys.h"

struct arena alloc_arena(u64 capacity)
{
    /* TODO(pryazha): Find reasonable maximum capacity through testing */
    assert(capacity <= (u64)gigabytes(16));
    if (!capacity)
        capacity = kilobytes(4);
    void *memory = sys_alloc(capacity);
    assert(memory);
    return (struct arena){memory, capacity, 0};
}

void release_arena(struct arena *arena)
{
    assert(arena);
    sys_free(arena->memory, arena->capacity);
    arena->memory = 0;
    arena->capacity = 0;
    arena->used = 0;
}

void *push_arena(struct arena *arena, u64 size)
{
    assert(arena);
    assert(arena->used + size <= arena->capacity);
    void *memory = arena->memory + arena->used;
    arena->used += size;
    return memory;
}

void pop_arena(struct arena *arena, u64 size)
{
    assert(arena);
    arena->used -= min(size, arena->used);
}