usr/src/lib/libbc/libc/stdio/common/setvbuf.c

   1 /*
   2  * CDDL HEADER START
   3  *
   4  * The contents of this file are subject to the terms of the
   5  * Common Development and Distribution License, Version 1.0 only
   6  * (the "License").  You may not use this file except in compliance
   7  * with the License.
   8  *
   9  * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
  10  * or http://www.opensolaris.org/os/licensing.
  11  * See the License for the specific language governing permissions
  12  * and limitations under the License.
  13  *
  14  * When distributing Covered Code, include this CDDL HEADER in each
  15  * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
  16  * If applicable, add the following below this CDDL HEADER, with the
  17  * fields enclosed by brackets "[]" replaced with your own identifying
  18  * information: Portions Copyright [yyyy] [name of copyright owner]
  19  *
  20  * CDDL HEADER END
  21  */
  22 /*
  23  * Copyright 1986 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1984 AT&T */
  28 /*        All Rights Reserved   */
  29
  30 #pragma ident   "%Z%%M% %I%     %E% SMI"  /* from S5R2 1.2 */
  31
  32 /*LINTLIBRARY*/
  33 #include <stdio.h>
  34
  35 extern void free();
  36 extern unsigned char (*_smbuf)[_SBFSIZ];
  37 extern char *malloc();
  38 extern void _getsmbuf();
  39
  40 int
  41 setvbuf(iop, buf, type, size)
  42 register FILE *iop;
  43 register char   *buf;
  44 register int type;
  45 register int size;
  46 {
  47         register int fno = fileno(iop);  /* file number */
  48
  49         if(iop->_base != NULL && iop->_flag & _IOMYBUF)
  50                 free((char*)iop->_base);
  51         iop->_flag &= ~(_IOMYBUF | _IONBF | _IOLBF);
  52         switch (type)  {
  53             /*note that the flags are the same as the possible values for type*/
  54             case _IONBF:
  55                 /* file is unbuffered except in fastio */
  56                 iop->_flag |= _IONBF;
  57                 /* use small buffers reserved for this */
  58                 iop->_base = _smbuf[fno];
  59                 iop->_bufsiz = _SBFSIZ;
  60                 break;
  61             case _IOLBF:
  62             case _IOFBF:
  63                 if (size < 0)
  64                         return -1;
  65                 iop->_flag |= type;
  66                 size = (size == 0) ? BUFSIZ : size;
  67                 /*
  68                 * need eight characters beyond bufend for stdio slop
  69                 */
  70                 if (size <= 8) {
  71                     size = BUFSIZ;
  72                     buf = NULL;
  73                 }
  74                 if (buf == NULL) {
  75                         size += 8;
  76                         buf = malloc((unsigned)size);
  77                         iop->_flag |= _IOMYBUF;
  78                 }
  79                 iop->_base = (unsigned char *)buf;
  80                 iop->_bufsiz = size - 8;
  81                 break;
  82             default:
  83                 return -1;
  84         }
  85         iop->_ptr = iop->_base;
  86         iop->_cnt = 0;
  87         return 0;
  88 }