ack/lang/pc/libpc/opn.c

/* $Id$ */
/*
 * (c) copyright 1983 by the Vrije Universiteit, Amsterdam, The Netherlands.
 *
 *          This product is part of the Amsterdam Compiler Kit.
 *
 * Permission to use, sell, duplicate or disclose this software must be
 * obtained in writing. Requests for such permissions may be sent to
 *
 *      Dr. Andrew S. Tanenbaum
 *      Wiskundig Seminarium
 *      Vrije Universiteit
 *      Postbox 7161
 *      1007 MC Amsterdam
 *      The Netherlands
 *
 */

/* Author: J.W. Stevenson */

#include <stdlib.h>
#include <fcntl.h>
#include <unistd.h>
#include "pc.h"

static int tmpfil(void)
{
	static char namebuf[] = "/tmp/plf.xxxxx";
	int i;
	char *p, *q;

	i = getpid();
	p = namebuf;
	q = p + 13;
	do
		*q++ = (i & 07) + '0';
	while (i >>= 3);
	*q = '\0';
	if ((i = creat(p, 0644)) < 0)
		if ((i = creat(p += 4, 0644)) < 0)
			if ((i = creat(p += 5, 0644)) < 0)
				goto error;
	if (close(i) != 0)
		goto error;
	if ((i = open(p, 2)) < 0)
		goto error;
	if (unlink(p) != 0)
	error:
		_trp(EREWR);
	return (i);
}

static int initfl(int descr, int sz, struct file* f)
{
	int i;

	_curfil = f;
	if (sz == 0)
	{
		sz++;
		descr |= TXTBIT;
	}
	for (i = 0; i < _extflc; i++)
		if (f == _extfl[i])
			break;
	if (i >= _extflc)
	{ /* local file */
		f->fname = "LOCAL";
		if ((descr & WRBIT) == 0 && (f->flags & 0377) == MAGIC)
		{
			_xcls(f);
			if (lseek(f->ufd, (long)0, 0) == -1)
				_trp(ERESET);
		}
		else
		{
			_cls(f);
			f->ufd = tmpfil();
		}
	}
	else
	{ /* external file */
		if (--i <= 0)
			return (0);
		if (i >= _pargc)
			_trp(EARGC);
		f->fname = _pargv[i];
		_cls(f);
		if ((descr & WRBIT) == 0)
		{
			if ((f->ufd = open(f->fname, 0)) < 0)
				_trp(ERESET);
		}
		else
		{
			if ((f->ufd = creat(f->fname, 0644)) < 0)
				_trp(EREWR);
		}
	}
	f->buflen = (sz > PC_BUFLEN ? sz : PC_BUFLEN - PC_BUFLEN % sz);
	f->size = sz;
	f->ptr = f->bufadr;
	f->flags = descr;
	return (1);
}

void _opn(int sz, struct file* f)
{

	if (initfl(MAGIC, sz, f))
		f->count = 0;
}

void _cre(int sz, struct file* f)
{

	if (initfl(WRBIT | EOFBIT | ELNBIT | MAGIC, sz, f))
		f->count = f->buflen;
}