/*-
 * Copyright (c) 1990, 1993
 *	The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * 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 University 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 REGENTS 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 REGENTS 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 <sys/param.h>
#include <unistd.h>
#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include "local.h"

int	__sdidinit;

#define	std(next, flags, file) \
	{next,NULL,0,0,flags,file,{0,0},{0,0},NULL,0,{0},{0}}
/*	 p r w flags file _bf z */

FILE __sF[3] = {
	std(&__sF[1], __SRD, STDIN_FILENO),
	std(&__sF[2], __SWR, STDOUT_FILENO),
	std(NULL, __SWR|__SNBF, STDERR_FILENO)
};

/*
 * Find a free FILE for fopen et al.
 */
FILE *
__sfp()
{
	FILE *fp, *tmp;

	if (!__sdidinit)
		__sinit();
	for (fp = &__sF[0];; fp = fp->next) {
		if (fp->_flags == 0)
			goto found;
		if (fp->next == NULL) {
			if ((tmp = malloc(sizeof(FILE))) == NULL)
				break;
			tmp->next = NULL;
			fp->next = tmp;
			fp = tmp;
			goto found;
		}
	}
	return (NULL);
found:
	fp->_flags = 1;		/* reserve this slot; caller sets real flags */
	fp->_p = NULL;		/* no current pointer */
	fp->_w = 0;		/* nothing to read or write */
	fp->_r = 0;
	fp->_bf._base = NULL;	/* no buffer */
	fp->_bf._size = 0;
	fp->_file = -1;		/* no file */
	fp->_ub._base = NULL;	/* no ungetc buffer */
	fp->_ub._size = 0;
	return (fp);
}

/*
 * exit() calls _cleanup() through *__cleanup, set whenever we
 * open or buffer a file.  This chicanery is done so that programs
 * that do not use stdio need not link it all in.
 *
 * The name `_cleanup' is, alas, fairly well known outside stdio.
b */
void
_cleanup()
{
	/* (void) _fwalk(fclose); */
	(void) _fwalk(__sflush);		/* `cheating' */
}

/*
 * __sinit() is called whenever stdio's internal variables must be set up.
 */
void
__sinit()
{
	/* make sure we clean up on exit */
	__cleanup = _cleanup;		/* conservative */
	__sdidinit = 1;
}