os161/kern/lib/array.c
2025-03-01 00:01:05 -05:00

136 lines
3.2 KiB
C

/*-
* Copyright (c) 2009 The NetBSD Foundation, Inc.
* All rights reserved.
*
* This code is derived from software contributed to The NetBSD Foundation
* by David A. Holland.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
* ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
* TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
* BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
*/
#define ARRAYINLINE
#include <types.h>
#include <kern/errno.h>
#include <lib.h>
#include <array.h>
struct array *
array_create(void)
{
struct array *a;
a = kmalloc(sizeof(*a));
if (a != NULL) {
array_init(a);
}
return a;
}
void
array_destroy(struct array *a)
{
array_cleanup(a);
kfree(a);
}
void
array_init(struct array *a)
{
a->num = a->max = 0;
a->v = NULL;
}
void
array_cleanup(struct array *a)
{
/*
* Require array to be empty - helps avoid memory leaks since
* we don't/can't free anything any contents may be pointing
* to.
*/
ARRAYASSERT(a->num == 0);
kfree(a->v);
#ifdef ARRAYS_CHECKED
a->v = NULL;
#endif
}
int
array_preallocate(struct array *a, unsigned num)
{
void **newptr;
unsigned newmax;
if (num > a->max) {
/* Don't touch A until the allocation succeeds. */
newmax = a->max;
while (num > newmax) {
newmax = newmax ? newmax*2 : 4;
}
/*
* We don't have krealloc, and it wouldn't be
* worthwhile to implement just for this. So just
* allocate a new block and copy. (Exercise: what
* about this and/or kmalloc makes it not worthwhile?)
*/
newptr = kmalloc(newmax*sizeof(*a->v));
if (newptr == NULL) {
return ENOMEM;
}
memcpy(newptr, a->v, a->num*sizeof(*a->v));
kfree(a->v);
a->v = newptr;
a->max = newmax;
}
return 0;
}
int
array_setsize(struct array *a, unsigned num)
{
int result;
result = array_preallocate(a, num);
if (result) {
return result;
}
a->num = num;
return 0;
}
void
array_remove(struct array *a, unsigned index)
{
unsigned num_to_move;
ARRAYASSERT(a->num <= a->max);
ARRAYASSERT(index < a->num);
num_to_move = a->num - (index + 1);
memmove(a->v + index, a->v + index+1, num_to_move*sizeof(void *));
a->num--;
}