src/libstatgrab/vector.c

/*
 * i-scream central monitoring system
 * http://www.i-scream.org
 * Copyright (C) 2000-2004 i-scream
 * 
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 * 
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
 * 02111-1307 USA
 *
 * $Id: vector.c,v 1.2 2004/04/05 00:20:05 ats Exp $
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif

#include <stdlib.h>

#include "vector.h"

void *statgrab_vector_resize(void *vector, vector_header *h, int count) {
        int new_count, i;

        /* Destroy any now-unused items. */
        if (count < h->used_count && h->destroy_fn != NULL) {
                for (i = count; i < h->used_count; i++) {
                        h->destroy_fn((void *) (vector + i * h->item_size));
                }
        }

        /* Round up the desired size to the next multiple of the block size. */
        new_count =  ((count - 1 + h->block_size) / h->block_size)
                     * h->block_size;

        /* Resize the vector if necessary. */
        if (new_count != h->alloc_count) {
                char *new_vector;

                new_vector = realloc(vector, new_count * h->item_size);
                if (new_vector == NULL && new_count != 0) {
                        /* Out of memory -- free the contents of the vector. */
                        statgrab_vector_resize(vector, h, 0);
                        /* And return the sentinel value to indicate failure. */
                        return statgrab_vector_sentinel;
                }

                vector = new_vector;
                h->alloc_count = new_count;
        }

        /* Initialise any new items. */
        if (count > h->used_count && h->init_fn != NULL) {
                for (i = h->used_count; i < count; i++) {
                        h->init_fn((void *) (vector + i * h->item_size));
                }
        }

        h->used_count = count;

        return vector;
}

Revision:	1.3
Committed:	Mon Apr 5 00:45:17 2004 UTC (20 years, 1 month ago) by ats
Content type:	text/plain
Branch:	MAIN
Changes since 1.2:	+9 -8 lines
Log Message:	Fix the strict-aliasing warnings. This is even uglier than the previous code, since it pushes a test for a sentinel value into the VECTOR_RESIZE macro. I'm pretty certain that the pointer-to-static-used-as-sentinel is my own invention. I'm not entirely convinced that it's a good idea, but I can't see anything technically wrong with it...
#	Content
1	/*
2	* i-scream central monitoring system
3	* http://www.i-scream.org
4	* Copyright (C) 2000-2004 i-scream
5	*
6	* This library is free software; you can redistribute it and/or
7	* modify it under the terms of the GNU Lesser General Public
8	* License as published by the Free Software Foundation; either
9	* version 2.1 of the License, or (at your option) any later version.
10	*
11	* This library is distributed in the hope that it will be useful,
12	* but WITHOUT ANY WARRANTY; without even the implied warranty of
13	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14	* Lesser General Public License for more details.
15	*
16	* You should have received a copy of the GNU Lesser General Public
17	* License along with this library; if not, write to the Free Software
18	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19	* 02111-1307 USA
20	*
21	* $Id: vector.c,v 1.2 2004/04/05 00:20:05 ats Exp $
22	*/
23
24	#ifdef HAVE_CONFIG_H
25	#include "config.h"
26	#endif
27
28	#include <stdlib.h>
29
30	#include "vector.h"
31
32	void statgrab_vector_resize(void vector, vector_header *h, int count) {
33	int new_count, i;
34
35	/* Destroy any now-unused items. */
36	if (count < h->used_count && h->destroy_fn != NULL) {
37	for (i = count; i < h->used_count; i++) {
38	h->destroy_fn((void ) (vector + i h->item_size));
39	}
40	}
41
42	/* Round up the desired size to the next multiple of the block size. */
43	new_count = ((count - 1 + h->block_size) / h->block_size)
44	* h->block_size;
45
46	/* Resize the vector if necessary. */
47	if (new_count != h->alloc_count) {
48	char *new_vector;
49
50	new_vector = realloc(vector, new_count * h->item_size);
51	if (new_vector == NULL && new_count != 0) {
52	/* Out of memory -- free the contents of the vector. */
53	statgrab_vector_resize(vector, h, 0);
54	/* And return the sentinel value to indicate failure. */
55	return statgrab_vector_sentinel;
56	}
57
58	vector = new_vector;
59	h->alloc_count = new_count;
60	}
61
62	/* Initialise any new items. */
63	if (count > h->used_count && h->init_fn != NULL) {
64	for (i = h->used_count; i < count; i++) {
65	h->init_fn((void ) (vector + i h->item_size));
66	}
67	}
68
69	h->used_count = count;
70
71	return vector;
72	}
73