buffer.c

/*
 * Copyright (c) 1995-2000 Kungliga Tekniska Högskolan
 * (Royal Institute of Technology, Stockholm, Sweden).
 * All rights reserved.
 *
 * 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.
 *
 * 3. Neither the name of the Institute nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE INSTITUTE 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 INSTITUTE 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.
 */

#include "common.h"
#include <stdio.h>
#include <err.h>
#include "roken.h"

RCSID("$Id$");

/*
 * Allocate a buffer enough to handle st->st_blksize, if
 * there is such a field, otherwise BUFSIZ.
 */

void *
alloc_buffer (void *oldbuf, size_t *sz, struct stat *st)
{
    size_t new_sz;

    new_sz = BUFSIZ;
#ifdef HAVE_STRUCT_STAT_ST_BLKSIZE
    if (st)
	new_sz = max(BUFSIZ, st->st_blksize);
#endif
    if(new_sz > *sz) {
	if (oldbuf)
	    free (oldbuf);
	oldbuf = malloc (new_sz);
	if (oldbuf == NULL) {
	    warn ("malloc");
	    *sz = 0;
	    return NULL;
	}
	*sz = new_sz;
    }
    return oldbuf;
}