1 /* WBUF.C

     2  * 

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

     4  * All rights reserved.

     5  */

     6 

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

     8 

     9 /*

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

    11  * All rights reserved.

    12  *

    13  * Redistribution and use in source and binary forms are permitted

    14  * provided that the above copyright notice and this paragraph are

    15  * duplicated in all such forms and that any documentation,

    16  * advertising materials, and other materials related to such

    17  * distribution and use acknowledge that the software was developed

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

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

    20  * from this software without specific prior written permission.

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

    22  * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED

    23  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.

    24  */

    25 

    26 #include <stdio.h>

    27 #include "LOCAL.H"

    28 #include "FVWRITE.H"

    29 

    30 /*

    31  * Write the given character into the (probably full) buffer for

    32  * the given file.  Flush the buffer out if it is or becomes full,

    33  * or if c=='\n' and the file is line buffered.

    34  */

    35 

    36 int

    37 __swbuf (register int c,register FILE *fp)

    38 {

    39   register int n;

    40 

    41   /* Ensure stdio has been initialized.  */

    42 

    43   CHECK_INIT (fp);

    44 

    45   /*

    46    * In case we cannot write, or longjmp takes us out early,

    47    * make sure _w is 0 (if fully- or un-buffered) or -_bf._size

    48    * (if line buffered) so that we will get called again.

    49    * If we did not do this, a sufficient number of putc()

    50    * calls might wrap _w from negative to positive.

    51    */

    52 

    53   fp->_w = fp->_lbfsize;

    54   if (cantwrite (fp))

    55     return EOF;

    56   c = (unsigned char) c;

    57 

    58   /*

    59    * If it is completely full, flush it out.  Then, in any case,

    60    * stuff c into the buffer.  If this causes the buffer to fill

    61    * completely, or if c is '\n' and the file is line buffered,

    62    * flush it (perhaps a second time).  The second flush will always

    63    * happen on unbuffered streams, where _bf._size==1; fflush()

    64    * guarantees that putc() will always call wbuf() by setting _w

    65    * to 0, so we need not do anything else.

    66    */

    67 

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

    69   if (n >= fp->_bf._size)

    70     {

    71       if (fflush (fp))

    72 	return EOF;

    73       n = 0;

    74     }

    75   fp->_w--;

    76   *fp->_p++ = (unsigned char)c;

    77   if (++n == fp->_bf._size || (fp->_flags & __SLBF && c == '\n'))

    78     if (fflush (fp))

    79       return EOF;

    80   return c;

    81 }