usr/src/cmd/lp/lib/msgs/fifo_buffs.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 1997 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 /*      Copyright (c) 1984, 1986, 1987, 1988, 1989 AT&T */
  28 /*        All Rights Reserved   */
  29
  30
  31 #pragma ident   "%Z%%M% %I%     %E% SMI"        /* SVr4.0 1.3   */
  32 /* LINTLIBRARY */
  33
  34
  35 #include        <errno.h>
  36 #include        <fcntl.h>
  37 #include        <stdio.h>
  38 #include        "lp.h"
  39 #include        "msgs.h"
  40
  41 static  fifobuffer_t    **FifoBufferTable       = NULL;
  42 static  int             FifoBufferTableSize     = 0;
  43
  44 /*
  45 **      Local functions
  46 */
  47 static  int             InitFifoBufferTable (void);
  48 static  int             GrowFifoBufferTable (int);
  49 static  fifobuffer_t    *NewFifoBuffer (int);
  50
  51
  52 int
  53 ResetFifoBuffer(int fd)
  54 {
  55         if ((!FifoBufferTableSize) && (InitFifoBufferTable () < 0))
  56                 return  -1;
  57
  58         if (fd >= FifoBufferTableSize)
  59                 return  0;
  60
  61         if (FifoBufferTable [fd]) {
  62                 FifoBufferTable [fd]->full = 0;
  63                 FifoBufferTable [fd]->psave =
  64                 FifoBufferTable [fd]->psave_end =
  65                         FifoBufferTable [fd]->save;
  66         }
  67         return  0;
  68 }
  69
  70
  71 fifobuffer_t *
  72 GetFifoBuffer(int fd)
  73 {
  74         if (fd < 0) {
  75                 errno = EINVAL;
  76                 return  NULL;
  77         }
  78         if ((fd >= FifoBufferTableSize) && (GrowFifoBufferTable (fd) < 0))
  79                 return  NULL;
  80
  81         if (!FifoBufferTable [fd]) {
  82                 if (!NewFifoBuffer (fd))
  83                         return  NULL;
  84
  85                 FifoBufferTable [fd]->full = 0;
  86                 FifoBufferTable [fd]->psave =
  87                 FifoBufferTable [fd]->psave_end =
  88                         FifoBufferTable [fd]->save;
  89         }
  90
  91         return  FifoBufferTable [fd];
  92 }
  93
  94
  95 static  int
  96 InitFifoBufferTable()
  97 {
  98         if (FifoBufferTableSize)
  99                 return  0;
 100
 101         FifoBufferTable = (fifobuffer_t **)
 102                 Calloc (100, sizeof (fifobuffer_t *));
 103         if (!FifoBufferTable)
 104                 return  -1;     /* ENOMEM is already set. */
 105
 106         FifoBufferTableSize = 100;
 107
 108         return  0;
 109 }
 110
 111
 112 static int
 113 GrowFifoBufferTable (int fd)
 114 {
 115         fifobuffer_t    **newpp;
 116
 117         newpp = (fifobuffer_t **)
 118                 Realloc ((void*)FifoBufferTable,
 119                 (fd+10)*sizeof (fifobuffer_t *));
 120         if (!newpp)
 121                 return  -1;     /* ENOMEM is already set. */
 122
 123         FifoBufferTableSize = fd+10;
 124
 125         return  0;
 126 }
 127
 128
 129 static fifobuffer_t *
 130 NewFifoBuffer(int fd)
 131 {
 132         int     i;
 133
 134         for (i=0; i < FifoBufferTableSize; i++)
 135         {
 136                 if (FifoBufferTable [i] &&
 137                     Fcntl (i, F_GETFL) < 0 &&
 138                     errno == EBADF)
 139                 {
 140                         FifoBufferTable [fd] = FifoBufferTable [i];
 141                         FifoBufferTable [i] = NULL;
 142                         return  FifoBufferTable [fd];
 143                 }
 144         }
 145         FifoBufferTable [fd] = (fifobuffer_t *)
 146                 Calloc (1, sizeof (fifobuffer_t));
 147
 148         return  FifoBufferTable [fd];
 149 }