thrieg/ft_malloc
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Thomas Rieg 2025-11-28 19:50:58 +01:00
commit 42653de246
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srcs/ft_free.c Normal file
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/* ************************************************************************** */
/* */
/* ::: :::::::: */
/* ft_free.c :+: :+: :+: */
/* +:+ +:+ +:+ */
/* By: thrieg < thrieg@student.42mulhouse.fr> +#+ +:+ +#+ */
/* +#+#+#+#+#+ +#+ */
/* Created: 2025/11/19 15:44:05 by thrieg #+# #+# */
/* Updated: 2025/11/25 16:21:10 by thrieg ### ########.fr */
/* */
/* ************************************************************************** */
#include "../includes/ft_malloc.h"
// returns non-0 (1) when the function munmap the zone
int defrag_zone(t_zone *zone)
{
t_header *header = (t_header *)(zone + 1);
char *last_adr = ((char *)zone) + zone->size - sizeof(t_header);
while ((((char *)header) + header->size) < last_adr)
{
t_header *next_header = (t_header *)(((char *)header) + sizeof(t_header) + header->size);
if (!header->occupied && !next_header->occupied)
{
header->size = header->size + sizeof(t_header) + next_header->size;
}
else
{
header = next_header;
}
}
// if only 1 free header left, mmunmap the zone
if (header == (t_header *)(zone + 1) && !header->occupied)
{
if (zone->type == E_SMALL)
{
if (g_state.small_zone == zone)
{
if (zone->next)
g_state.small_zone = zone->next;
else
return (0); // last small zone, don't deallocate to avoid mmap stress
}
}
else if (zone->type == E_TINY)
{
if (g_state.tiny_zone == zone)
{
if (zone->next)
g_state.tiny_zone = zone->next;
else
return (0); // last tiny zone, don't deallocate to avoid mmap stress
}
}
if (zone->prev)
zone->prev->next = zone->next;
if (zone->next)
zone->next->prev = zone->prev;
munmap(zone, zone->size);
return (1);
}
return (0);
}
void free(void *ptr)
{
pthread_mutex_lock(&g_mut);
if (!ptr)
return ((void)pthread_mutex_unlock(&g_mut));
t_header *header = ((t_header *)ptr) - 1;
if (header->zone->type == E_LARGE)
{
if (header->zone->prev)
header->zone->prev->next = header->zone->next;
if (header->zone->next)
header->zone->next->prev = header->zone->prev;
if (header->zone == g_state.large_zone)
{
if (g_state.large_zone->next)
g_state.large_zone = g_state.large_zone->next;
else
g_state.large_zone = NULL;
}
void *ptr = header->zone;
size_t len = header->zone->size;
munmap(ptr, len);
}
else if (header->zone->type == E_SMALL)
{
header->occupied = false;
defrag_zone(header->zone);
}
else if (header->zone->type == E_TINY)
{
header->occupied = false;
defrag_zone(header->zone);
}
pthread_mutex_unlock(&g_mut);
}