143 lines
3.5 KiB
C
143 lines
3.5 KiB
C
/* ************************************************************************** */
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/* */
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/* ::: :::::::: */
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/* malloc.c :+: :+: :+: */
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/* +:+ +:+ +:+ */
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/* By: tomoron <tomoron@student.42angouleme.fr> +#+ +:+ +#+ */
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/* +#+#+#+#+#+ +#+ */
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/* Created: 2024/11/23 17:19:59 by tomoron #+# #+# */
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/* Updated: 2024/12/01 03:05:08 by tomoron ### ########.fr */
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/* */
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/* ************************************************************************** */
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#include "includes/malloc.h"
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#include <stdio.h>
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#include <errno.h>
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#include <string.h>
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t_allocations g_allocs;
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void *get_memory(size_t size, int no_write)
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{
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t_mem_bloc *bloc;
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bloc = mmap(0, size, PROT_WRITE | PROT_READ, MAP_ANONYMOUS | MAP_PRIVATE,
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-1, 0);
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if (bloc == MAP_FAILED)
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return (0);
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if(no_write)
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return(bloc);
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bloc->space_left = size - sizeof(t_mem_bloc);
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bloc->next = 0;
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return (bloc);
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}
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t_alloc *reserve_addr(t_alloc *addr, size_t size, t_alloc *prev,
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t_mem_bloc *bloc)
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{
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t_alloc *tmp;
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if ((t_ul)addr % 16)
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addr = (t_alloc *)((char *)addr + (16 - ((t_ul)addr % 16)));
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addr->size = size;
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bloc->space_left -= (size + sizeof(t_alloc));
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if (prev)
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{
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tmp = prev->next;
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prev->next = addr;
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addr->next = tmp;
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}
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else
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addr->next = 0;
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return (addr + 1);
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}
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t_alloc *get_suitable_addr_in_bloc(t_mem_bloc *bloc, size_t size)
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{
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t_alloc *tmp;
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size_t space_left;
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size_t free_space;
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tmp = bloc->first; //alloc when first alloc has been removed
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space_left = bloc->space_left;
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while (tmp->next)
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{
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free_space = ((t_ul)tmp->next - (t_ul)tmp) - (tmp->size + sizeof(t_alloc));
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if (free_space >= size + sizeof(t_alloc))
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return (reserve_addr(
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(void *)((char *)tmp->next + tmp->size + sizeof(t_alloc)),
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size, tmp, bloc));
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space_left -= free_space;
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tmp = tmp->next;
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}
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if (space_left >= size + sizeof(t_alloc))
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return (reserve_addr(
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(t_alloc *)((char *)tmp + tmp->size + sizeof(t_alloc)),
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size, tmp, bloc));
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return (0);
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}
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t_mem_bloc *create_new_bloc(int is_small, t_mem_bloc **bloc, t_mem_bloc *prev)
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{
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t_mem_bloc *new;
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size_t mmap_size;
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if (is_small)
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mmap_size = SMALL_BLOC_SIZE;
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else
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mmap_size = TINY_BLOC_SIZE;
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new = get_memory(mmap_size, 0);
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if (!new)
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return (0);
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new->first = (t_alloc *)(new + 1);
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if (prev)
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prev->next = new;
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if (!*bloc)
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*bloc = new;
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return (new);
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}
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void *pre_allocated(size_t size, t_mem_bloc **bloc, int is_small)
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{
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t_mem_bloc *tmp;
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t_mem_bloc *prev;
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t_alloc *res;
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tmp = *bloc;
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prev = *bloc;
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res = 0;
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while (tmp)
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{
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if (tmp->space_left >= size)
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{
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res = get_suitable_addr_in_bloc(tmp, size);
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if (res)
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return (res);
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}
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prev = tmp;
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tmp = tmp->next;
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}
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tmp = create_new_bloc(is_small, bloc, prev);
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if (!tmp)
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return (0);
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return (reserve_addr((void *)tmp + sizeof(t_mem_bloc), size, 0, tmp));
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}
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void *ft_malloc(size_t size)
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{
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t_alloc *new;
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if (size <= TINY_MALLOC)
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return (pre_allocated(size, &(g_allocs.tiny), 0));
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else if (size <= SMALL_MALLOC)
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return (pre_allocated(size, &(g_allocs.small), 1));
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new = get_memory(size + sizeof(t_alloc), 1);
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if (!new)
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return (0);
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new->size = size;
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new->next = g_allocs.large;
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g_allocs.large = new;
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return ((char *)new + sizeof(t_alloc));
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}
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