/* REFILL.C

 * 

 * Portions Copyright (c) 1990-1999 Nokia Corporation and/or its subsidiary(-ies).

 * All rights reserved.

 */

/* No user fns here.  Pesch 15apr92. */

/*

 * Copyright (c) 1990 The Regents of the University of California.

 * All rights reserved.

 *

 * Redistribution and use in source and binary forms are permitted

 * provided that the above copyright notice and this paragraph are

 * duplicated in all such forms and that any documentation,

 * advertising materials, and other materials related to such

 * distribution and use acknowledge that the software was developed

 * by the University of California, Berkeley.  The name of the

 * University may not be used to endorse or promote products derived

 * from this software without specific prior written permission.

 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR

 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED

 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

 */

#include <stdio_r.h>

#include "LOCAL.H"

#include <stdlib_r.h>

static int

lflush (FILE *fp)

{

  if ((fp->_flags & (__SLBF | __SWR)) == (__SLBF | __SWR))

    return fflush (fp);

  return 0;

}

/*

 * Refill a stdio buffer.

 * Return EOF on eof or error, 0 otherwise.

 */

int

__srefill (register FILE * fp)

{

  /* make sure stdio is set up */

  CHECK_INIT (fp);

  fp->_r = 0;			/* largely a convenience for callers */

  /* SysV does not make this test; take it out for compatibility */

  if (fp->_flags & __SEOF)

    return EOF;

  /* if not already reading, have to be reading and writing */

  if ((fp->_flags & __SRD) == 0)

    {

      if ((fp->_flags & __SRW) == 0)

	return EOF;

      /* switch to reading */

      if (fp->_flags & __SWR)

	{

	  if (fflush (fp))

	    return EOF;

	  fp->_flags &= ~__SWR;

	  fp->_w = 0;

	  fp->_lbfsize = 0;

	}

      fp->_flags |= __SRD;

    }

  else

    {

      /*

       * We were reading.  If there is an ungetc buffer,

       * we must have been reading from that.  Drop it,

       * restoring the previous buffer (if any).  If there

       * is anything in that buffer, return.

       */

      if (HASUB (fp))

	{

	  FREEUB (fp);

	  if ((fp->_r = fp->_ur) != 0)

	    {

	      fp->_p = fp->_up;

	      return 0;

	    }

	}

    }

  if (fp->_bf._base == NULL)

    __smakebuf (fp);

  /*

   * Before reading from a line buffered or unbuffered file,

   * flush all line buffered output files, per the ANSI C

   * standard.

   */

  if (fp->_flags & (__SLBF | __SNBF))

    (void) _fwalk (fp->_data, lflush);

  fp->_p = fp->_bf._base;

  fp->_r = (*fp->_read) (fp->_cookie, (char *) fp->_p, fp->_bf._size);

  fp->_flags &= ~__SMOD;	/* buffer contents are again pristine */

  if (fp->_r <= 0)

    {

      if (fp->_r == 0)

	fp->_flags |= __SEOF;

      else

	{

	  fp->_r = 0;

	  fp->_flags |= __SERR;

	}

      return EOF;

    }

  return 0;

}