/* something like the origonal
 * from Dale Schumacher's dLibs
 */

#include <stdio.h>

extern long lseek(), tell();

long ftell(fp)
FILE *fp;
{
    long rv, count = fp->_cnt, adjust = 0;
    unsigned int f = fp->_flag;

    if( ((f & _IOREAD) && (!(f & _IOBIN))) ||
       (count == 0)			   ||
       (f & _IONBF) )
    {
	fflush(fp);	
	rv = lseek(fp->_file, 0L, SEEK_CUR);
    }
    else
    {
	if(f & _IOREAD)
	    adjust = -count;
	else if(f & (_IOWRT | _IORW))
	{
	    if(f & _IOWRT)
		adjust = count;
	}
	else return -1L;

	rv = lseek(fp->_file, 0L, SEEK_CUR);
    }
    return (rv < 0) ? -1L : rv + adjust;
}

void rewind(fp)
register FILE *fp;
{
    register long rv;
    
    fflush(fp);
    rv = lseek(fp->_file, 0L, SEEK_SET);
    fp->_flag &= ~(_IOEOF|_IOERR);
}

int fseek(fp, offset, origin)
FILE *fp;
long offset;
int origin;
{
    long pos, count;
    unsigned int f;
    int rv;
    
    /* Clear end of file flag */
    f = (fp->_flag &= ~_IOEOF);
    count = fp->_cnt;
    
    if((!(f & _IOBIN)) 	    ||
       (f & (_IOWRT))	    ||
       (count == 0)         ||
       (f & _IONBF)	    || 
       (origin == SEEK_END) )
    {
	rv = fflush(fp);
	return ((rv == EOF) || (lseek(fp->_file, offset, origin) < 0)) ?
	    -1 : 0;
    }
    
    /* figure out if where we are going is still within the buffer */
    pos = offset;
    if(origin == SEEK_SET)
    {
	register long realpos;
	if((realpos = tell(fp->_file)) < 0)
	{	/* no point carrying on */
	    return -1;
	}
	pos += count - realpos;
    }
    else offset -= count;	/* we were already count ahead */
    
    if( (!(f & _IORW)) && (pos <= count) && (pos >= (fp->_base - fp->_ptr)) )
    {
	fp->_ptr += pos;
	fp->_cnt -= pos;
	return 0;
    }
    /* otherwise */
    fp->_ptr = fp->_base;
    fp->_cnt = 0;
    if(f & _IORW) fp->_flag &= ~_IOREAD;
    return (lseek(fp->_file, offset, origin) < 0) ? -1 : 0;
}