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/*
 * Copyright (c) 2001-2002 Packet Design, LLC.
 * All rights reserved.
 * 
 * Subject to the following obligations and disclaimer of warranty,
 * use and redistribution of this software, in source or object code
 * forms, with or without modifications are expressly permitted by
 * Packet Design; provided, however, that:
 * 
 *    (i)  Any and all reproductions of the source or object code
 *         must include the copyright notice above and the following
 *         disclaimer of warranties; and
 *    (ii) No rights are granted, in any manner or form, to use
 *         Packet Design trademarks, including the mark "PACKET DESIGN"
 *         on advertising, endorsements, or otherwise except as such
 *         appears in the above copyright notice or in the software.
 * 
 * THIS SOFTWARE IS BEING PROVIDED BY PACKET DESIGN "AS IS", AND
 * TO THE MAXIMUM EXTENT PERMITTED BY LAW, PACKET DESIGN MAKES NO
 * REPRESENTATIONS OR WARRANTIES, EXPRESS OR IMPLIED, REGARDING
 * THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY AND ALL IMPLIED
 * WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE,
 * OR NON-INFRINGEMENT.  PACKET DESIGN DOES NOT WARRANT, GUARANTEE,
 * OR MAKE ANY REPRESENTATIONS REGARDING THE USE OF, OR THE RESULTS
 * OF THE USE OF THIS SOFTWARE IN TERMS OF ITS CORRECTNESS, ACCURACY,
 * RELIABILITY OR OTHERWISE.  IN NO EVENT SHALL PACKET DESIGN BE
 * LIABLE FOR ANY DAMAGES RESULTING FROM OR ARISING OUT OF ANY USE
 * OF THIS SOFTWARE, INCLUDING WITHOUT LIMITATION, ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, PUNITIVE, OR CONSEQUENTIAL
 * DAMAGES, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES, LOSS OF
 * USE, DATA OR PROFITS, HOWEVER CAUSED AND UNDER 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 PACKET DESIGN IS ADVISED OF
 * THE POSSIBILITY OF SUCH DAMAGE.
 *
 * Author: Archie Cobbs <archie@freebsd.org>
 */

#include <sys/types.h>

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

#include "structs/structs.h"
#include "structs/type/array.h"

#include "util/typed_mem.h"
#include "io/count_fp.h"

#define MEM_TYPE		"count_fp"

/* Our state */
struct count_info {
	FILE		*fp;
	off_t		remain;
	int		closeit;
};

/*
 * Internal functions
 */
static int	count_read(void *cookie, char *buf, int len);
static int	count_close(void *cookie);

/*
 * Create a FILE * that reads a limited amount from another FILE *.
 */
FILE *
count_fopen(FILE *fp, off_t count, int closeit)
{
	struct count_info *c;

	/* Create info */
	if ((c = MALLOC(MEM_TYPE, sizeof(*c))) == NULL)
		return (NULL);
	memset(c, 0, sizeof(*c));
	c->fp = fp;
	c->remain = count;
	c->closeit = closeit;

	/* Create new FILE * */
	if ((fp = funopen(c, count_read, NULL, NULL, count_close)) == NULL) {
		FREE(MEM_TYPE, c);
		return (NULL);
	}

	/* Set to non-buffered so we don't read to much from underlying fp */
	setbuf(fp, NULL);

	/* Done */
	return (fp);
}

/*
 * Read from a count_fp.
 */
static int
count_read(void *cookie, char *buf, int len)
{
	struct count_info *const c = cookie;
	int ret;

	if (c->remain == 0)
		return (0);
	if (len > c->remain)
		len = c->remain;
	if ((ret = fread(buf, 1, len, c->fp)) != len) {
		if (ferror(c->fp))
			return (-1);
	}
	c->remain -= ret;
	return (ret);
}

/*
 * Close a count_fp.
 */
static int
count_close(void *cookie)
{
	struct count_info *const c = cookie;

	if (c->closeit)
		fclose(c->fp);
	FREE(MEM_TYPE, c);
	return (0);
}