cde/programs/dtksh/ksh93/src/lib/libast/sfio/sfswap.c

   1 /*
   2  * CDE - Common Desktop Environment
   3  *
   4  * Copyright (c) 1993-2012, The Open Group. All rights reserved.
   5  *
   6  * These libraries and programs are free software; you can
   7  * redistribute them and/or modify them under the terms of the GNU
   8  * Lesser General Public License as published by the Free Software
   9  * Foundation; either version 2 of the License, or (at your option)
  10  * any later version.
  11  *
  12  * These libraries and programs are distributed in the hope that
  13  * they will be useful, but WITHOUT ANY WARRANTY; without even the
  14  * implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  15  * PURPOSE. See the GNU Lesser General Public License for more
  16  * details.
  17  *
  18  * You should have received a copy of the GNU Lesser General Public
  19  * License along with these librararies and programs; if not, write
  20  * to the Free Software Foundation, Inc., 51 Franklin Street, Fifth
  21  * Floor, Boston, MA 02110-1301 USA
  22  */
  23 /* $XConsortium: sfswap.c /main/3 1995/11/01 18:37:12 rswiston $ */
  24 /***************************************************************
  25 *                                                              *
  26 *                      AT&T - PROPRIETARY                      *
  27 *                                                              *
  28 *         THIS IS PROPRIETARY SOURCE CODE LICENSED BY          *
  29 *                          AT&T CORP.                          *
  30 *                                                              *
  31 *                Copyright (c) 1995 AT&T Corp.                 *
  32 *                     All Rights Reserved                      *
  33 *                                                              *
  34 *           This software is licensed by AT&T Corp.            *
  35 *       under the terms and conditions of the license in       *
  36 *       http://www.research.att.com/orgs/ssr/book/reuse        *
  37 *                                                              *
  38 *               This software was created by the               *
  39 *           Software Engineering Research Department           *
  40 *                    AT&T Bell Laboratories                    *
  41 *                                                              *
  42 *               For further information contact                *
  43 *                     gsf@research.att.com                     *
  44 *                                                              *
  45 ***************************************************************/
  46 #include        "sfhdr.h"
  47
  48 /*      Swap two streams. If the second argument is NULL,
  49 **      a new stream will be created. Always return the second argument
  50 **      or the new stream. Note that this function will always work
  51 **      unless streams are locked by SF_PUSH.
  52 **
  53 **      Written by Kiem-Phong Vo (02/07/94)
  54 */
  55
  56 #if __STD_C
  57 Sfio_t* sfswap(reg Sfio_t* f1, reg Sfio_t* f2)
  58 #else
  59 Sfio_t* sfswap(f1,f2)
  60 reg Sfio_t*     f1;
  61 reg Sfio_t*     f2;
  62 #endif
  63 {
  64         Sfio_t  tmp;
  65         int     f1pool, f2pool, f1mode, f2mode, f1flags, f2flags;
  66
  67         if(!f1 || (f1->mode&SF_AVAIL) || (SFFROZEN(f1) && (f1->mode&SF_PUSH)) )
  68                 return NIL(Sfio_t*);
  69         if(f2 && SFFROZEN(f2) && (f2->mode&SF_PUSH) )
  70                 return NIL(Sfio_t*);
  71         if(f1 == f2)
  72                 return f2;
  73
  74         f1mode = f1->mode;
  75         SFLOCK(f1,0);
  76         f1->mode |= SF_PUSH;            /* make sure there is no recursion on f1 */
  77
  78         if(f2)
  79         {       f2mode = f2->mode;
  80                 SFLOCK(f2,0);
  81                 f2->mode |= SF_PUSH;    /* make sure there is no recursion on f2 */
  82         }
  83         else
  84         {       f2 = f1->file == 0 ? sfstdin :
  85                      f1->file == 1 ? sfstdout :
  86                      f1->file == 2 ? sfstderr : NIL(Sfio_t*);
  87                 if((!f2 || !(f2->mode&SF_AVAIL)) )
  88                 {       if(!SFALLOC(f2) )
  89                         {       f1->mode = f1mode;
  90                                 SFOPEN(f1,0);
  91                                 return NIL(Sfio_t*);
  92                         }
  93                         else    SFCLEAR(f2);
  94                 }
  95                 f2->mode = SF_AVAIL|SF_LOCK;
  96                 f2mode = SF_AVAIL;
  97         }
  98
  99         if(!f1->pool)
 100                 f1pool = -1;
 101         else for(f1pool = f1->pool->n_sf-1; f1pool >= 0; --f1pool)
 102                 if(f1->pool->sf[f1pool] == f1)
 103                         break;
 104         if(!f2->pool)
 105                 f2pool = -1;
 106         else for(f2pool = f2->pool->n_sf-1; f2pool >= 0; --f2pool)
 107                 if(f2->pool->sf[f2pool] == f2)
 108                         break;
 109
 110         f1flags = f1->flags;
 111         f2flags = f2->flags;
 112
 113         /* swap image and pool entries */
 114         memcpy((Void_t*)(&tmp),(Void_t*)f1,sizeof(Sfio_t));
 115         memcpy((Void_t*)f1,(Void_t*)f2,sizeof(Sfio_t));
 116         memcpy((Void_t*)f2,(Void_t*)(&tmp),sizeof(Sfio_t));
 117         if(f2pool >= 0)
 118                 f1->pool->sf[f2pool] = f1;
 119         if(f1pool >= 0)
 120                 f2->pool->sf[f1pool] = f2;
 121
 122         _sfswap(f1,f2,0);
 123
 124         if(f2flags&SF_STATIC)
 125                 f2->flags |= SF_STATIC;
 126         else    f2->flags &= ~SF_STATIC;
 127
 128         if(f1flags&SF_STATIC)
 129                 f1->flags |= SF_STATIC;
 130         else    f1->flags &= ~SF_STATIC;
 131
 132         if(f2mode&SF_AVAIL)     /* swapping to a closed stream */
 133         {       if(!(f1->flags&SF_STATIC) )
 134                         SFFREE(f1);
 135         }
 136         else
 137         {       f1->mode = f2mode;
 138                 SFOPEN(f1,0);
 139         }
 140
 141         f2->mode = f1mode;
 142         SFOPEN(f2,0);
 143         return f2;
 144 }