/*
 *  ircd-ratbox: A slightly useful ircd.
 *  fileio.c: Provides a file input-output interface to ircd.
 *
 *  Copyright (C) 1990 Jarkko Oikarinen and University of Oulu, Co Center
 *  Copyright (C) 1996-2002 Hybrid Development Team
 *  Copyright (C) 2002-2004 ircd-ratbox development team
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program 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 General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with this program; if not, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307
 *  USA
 *
 *  $Id: fileio.c,v 1.1 2005/02/15 19:16:09 chopin Exp $
 */
#include "fileio.h"
#define s_assert(x)

static int
file_open(const char *filename, int mode, int fmode)
{
	int fd;
	fd = open(filename, mode, fmode);
	if(fd == MAXCONNECTIONS)
	{
		close(fd);	/* Too many FDs! */
		errno = ENFILE;
		fd = -1;
	}

	return fd;
}

FBFILE *
fbopen(const char *filename, const char *mode)
{
	int openmode = 0;
	int pmode = 0;
	FBFILE *fb = NULL;
	int fd;
	s_assert(filename);
	s_assert(mode);

	if(filename == NULL || mode == NULL)
	{
		errno = EINVAL;
		return NULL;
	}
	while (*mode)
	{
		switch (*mode)
		{
		case 'r':
			openmode = O_RDONLY;
			break;
		case 'w':
			openmode = O_WRONLY | O_CREAT | O_TRUNC;
			pmode = 0644;
			break;
		case 'a':
			openmode = O_WRONLY | O_CREAT | O_APPEND;
			pmode = 0644;
			break;
		case '+':
			openmode &= ~(O_RDONLY | O_WRONLY);
			openmode |= O_RDWR;
			break;
		default:
			break;
		}
		++mode;
	}

	if((fd = file_open(filename, openmode, pmode)) == -1)
	{
		return fb;
	}

	if(NULL == (fb = fdbopen(fd, NULL)))
		close(fd);
	return fb;
}

FBFILE *
fdbopen(int fd, const char *mode)
{
	/*
	 * ignore mode, if file descriptor hasn't been opened with the
	 * correct mode, the first use will fail
	 */
	FBFILE *fb = (FBFILE *) MyMalloc(sizeof(FBFILE));
	if(NULL != fb)
	{
		fb->ptr = fb->endp = fb->buf;
		fb->fd = fd;
		fb->flags = 0;
		fb->pbptr = (char *) NULL;
	}
	return fb;
}

void
fbclose(FBFILE * fb)
{
	s_assert(fb);
	if(fb != NULL)
	{
		close(fb->fd);
		MyFree(fb);
	}
	else
		errno = EINVAL;

}

static int
fbfill(FBFILE * fb)
{
	int n;
	s_assert(fb);
	if(fb == NULL)
	{
		errno = EINVAL;
		return -1;
	}
	if(fb->flags)
		return -1;
	n = read(fb->fd, fb->buf, BUFSIZ);
	if(0 < n)
	{
		fb->ptr = fb->buf;
		fb->endp = fb->buf + n;
	}
	else if(n < 0)
		fb->flags |= FB_FAIL;
	else
		fb->flags |= FB_EOF;
	return n;
}

int
fbgetc(FBFILE * fb)
{
	s_assert(fb);
	if(fb == NULL)
	{
		errno = EINVAL;
		return -1;
	}
	if(fb->pbptr)
	{
		if((fb->pbptr == (fb->pbuf + BUFSIZ)) || (!*fb->pbptr))
			fb->pbptr = NULL;
	}

	if(fb->ptr < fb->endp || fbfill(fb) > 0)
		return *fb->ptr++;
	return EOF;
}

void
fbungetc(char c, FBFILE * fb)
{
	s_assert(fb);
	if(fb == NULL)
	{
		errno = EINVAL;
		return;
	}
	if(!fb->pbptr)
	{
		fb->pbptr = fb->pbuf + BUFSIZ;
	}

	if(fb->pbptr != fb->pbuf)
	{
		fb->pbptr--;
		*fb->pbptr = c;
	}
}

char *
fbgets(char *buf, size_t len, FBFILE * fb)
{
	char *p = buf;
	s_assert(buf);
	s_assert(fb);
	s_assert(0 < len);

	if(fb == NULL || buf == NULL)
	{
		errno = EINVAL;
		return NULL;
	}
	if(fb->pbptr)
	{
		strlcpy(buf, fb->pbptr, len);
		fb->pbptr = NULL;
		return (buf);
	}

	if(fb->ptr == fb->endp && fbfill(fb) < 1)
		return 0;
	--len;
	while (len--)
	{
		*p = *fb->ptr++;
		if('\n' == *p)
		{
			++p;
			break;
		}
		/*
		 * deal with CR's
		 */
		else if('\r' == *p)
		{
			if(fb->ptr < fb->endp || fbfill(fb) > 0)
			{
				if('\n' == *fb->ptr)
					++fb->ptr;
			}
			*p++ = '\n';
			break;
		}
		++p;
		if(fb->ptr == fb->endp && fbfill(fb) < 1)
			break;
	}
	*p = '\0';
	return buf;
}

int
fbputs(const char *str, FBFILE * fb)
{
	int n = -1;
	s_assert(str);
	s_assert(fb);

	if(str == NULL || fb == NULL)
	{
		errno = EINVAL;
		return -1;
	}
	if(0 == fb->flags)
	{
		n = write(fb->fd, str, strlen(str));
		if(-1 == n)
			fb->flags |= FB_FAIL;
	}
	return n;
}

int
fbstat(struct stat *sb, FBFILE * fb)
{
	s_assert(sb);
	s_assert(fb);
	if(sb == NULL || fb == NULL)
	{
		errno = EINVAL;
		return -1;
	}
	return fstat(fb->fd, sb);
}