add free

inc/ft_malloc.h

@@ -4,14 +4,19 @@
 # include <stddef.h>
 # include <stdint.h>
 
+# define MIN_ALLOC_UNITS 100
+
 typedef struct 		s_header
 {
 	struct s_header	*next;
 	size_t			units;
 } 					t_header;
 
+# define UINIT (sizeof(t_header))
+
+
 static t_header		base;
-static t_header		*freep = NULL;
+static t_header		*free_blocks = NULL;
 
 void				free(void *ptr);
 void				*malloc(size_t size);

src/free.c

@@ -0,0 +1,29 @@
+#include "ft_malloc.h"
+
+void			free(void *used)
+{
+	t_header 	*runner;
+	t_header	*to_be_freed;
+
+	to_be_freed = (t_header *)used - UINIT;
+	runner = free_blocks;
+	while(!(to_be_freed > runner && to_be_freed < runner->next))
+	{
+		if (runner >= runner->next && (to_be_freed > runner || to_be_freed < runner->next))
+			break ;
+		runner = runner->next;
+	}
+	if (to_be_freed + to_be_freed->units == runner->next)
+	{
+		to_be_freed->units += runner->units;
+		to_be_freed->next = runner->next->next;
+	}
+	else if (runner + runner->units == to_be_freed)
+	{
+		runner->units += to_be_freed->units;
+		runner->next = to_be_freed->next;
+	}
+	else
+		runner->next = to_be_freed;
+	free_blocks = runner;
+}

src/malloc.c

@@ -1,9 +1,17 @@
 #include "ft_malloc.h"
+#include <sys/mman.h>
 
-t_header	*morecore(size_t size)
+t_header	*morecore(size_t nuints)
 {
-	(void)size;
-	return NULL;
+	t_header	*block;
+	if (nuints < MIN_ALLOC_UNITS)
+		nuints = MIN_ALLOC_UNITS;
+	block = mmap(NULL, nuints * UINIT, PROT_READ | PROT_WRITE, MAP_ANON, -1, 0);
+	if (block == MAP_FAILED)
+		return (NULL);
+	block->units = nuints;
+	free((void *)(block + UINIT));
+	return free_blocks;
 }
 
 void	*malloc(size_t size)
@@ -14,10 +22,10 @@ void	*malloc(size_t size)
 	void		*space;
 
 	space = NULL;
-	nunits = (size + sizeof(t_header) - 1) / (sizeof(t_header) + 1);
-	if ((prev = freep) == NULL)
+	nunits = (size + UINIT - 1) / (UINIT + 1);
+	if ((prev = free_blocks) == NULL)
 	{
-		base.next = freep = prev = &base;
+		base.next = free_blocks = prev = &base;
 		base.units = 0;
 	}
 	while(!space)
@@ -34,6 +42,11 @@ void	*malloc(size_t size)
 				curr->units = nunits;
 			}
 		}
+		free_blocks = prev;
+		space = (void *)(curr + UINIT);
+		if (curr == free_blocks)
+			if ((curr = morecore(nunits)) == NULL)
+				return (NULL);
 		prev = curr;
 		curr = curr->next;
 	}