usr/klibc/realloc.c

/*
 * realloc.c
 */

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

#include "malloc.h"

/* FIXME: This is cheesy, it should be fixed later */

void *realloc(void *ptr, size_t size)
{
	struct free_arena_header *ah;
	void *newptr;
	size_t oldsize;

	if (!ptr)
		return malloc(size);

	if (size == 0) {
		free(ptr);
		return NULL;
	}

	/* Add the obligatory arena header, and round up */
	size = (size + 2 * sizeof(struct arena_header) - 1) & ARENA_SIZE_MASK;

	ah = (struct free_arena_header *)
	    ((struct arena_header *)ptr - 1);

	if (ah->a.size >= size && size >= (ah->a.size >> 2)) {
		/* This field is a good size already. */
		return ptr;
	} else {
		/* Make me a new block.  This is kind of bogus; we should
		   be checking the following block to see if we can do an
		   in-place adjustment... fix that later. */

		oldsize = ah->a.size - sizeof(struct arena_header);

		newptr = malloc(size);
		memcpy(newptr, ptr, (size < oldsize) ? size : oldsize);
		free(ptr);

		return newptr;
	}
}
1	/*
2	* realloc.c
3	*/
4
5	#include <stdlib.h>
6	#include <string.h>
7
8	#include "malloc.h"
9
10	/* FIXME: This is cheesy, it should be fixed later */
11
12	void realloc(void ptr, size_t size)
13	{
14	struct free_arena_header *ah;
15	void *newptr;
16	size_t oldsize;
17
18	if (!ptr)
19	return malloc(size);
20
21	if (size == 0) {
22	free(ptr);
23	return NULL;
24	}
25
26	/* Add the obligatory arena header, and round up */
27	size = (size + 2 * sizeof(struct arena_header) - 1) & ARENA_SIZE_MASK;
28
29	ah = (struct free_arena_header *)
30	((struct arena_header *)ptr - 1);
31
32	if (ah->a.size >= size && size >= (ah->a.size >> 2)) {
33	/* This field is a good size already. */
34	return ptr;
35	} else {
36	/* Make me a new block. This is kind of bogus; we should
37	be checking the following block to see if we can do an
38	in-place adjustment... fix that later. */
39
40	oldsize = ah->a.size - sizeof(struct arena_header);
41
42	newptr = malloc(size);
43	memcpy(newptr, ptr, (size < oldsize) ? size : oldsize);
44	free(ptr);
45
46	return newptr;
47	}
48	}