usr/src/cmd/sort/common/streams_array.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 2004 Sun Microsystems, Inc.  All rights reserved.
  24  * Use is subject to license terms.
  25  */
  26
  27 #pragma ident   "%Z%%M% %I%     %E% SMI"
  28
  29 #include "streams_array.h"
  30 #include "streams_common.h"
  31
  32 /*
  33  * Single-byte character memory map-based streams implementation
  34  */
  35
  36 static int
  37 stream_array_prime(stream_t *str)
  38 {
  39         ASSERT((str->s_status & STREAM_SOURCE_MASK) == STREAM_ARRAY);
  40
  41         str->s_type.LA.s_cur_index = MIN(0, str->s_type.LA.s_array_size - 1);
  42         if (str->s_type.LA.s_cur_index >= 0)
  43                 copy_line_rec(
  44                     str->s_type.LA.s_array[str->s_type.LA.s_cur_index],
  45                     &str->s_current);
  46         else {
  47                 stream_set(str, STREAM_EOS_REACHED);
  48                 stream_unset(str, STREAM_PRIMED);
  49                 return (PRIME_FAILED_EMPTY_FILE);
  50         }
  51
  52         stream_set(str, STREAM_PRIMED);
  53
  54         return (PRIME_SUCCEEDED);
  55 }
  56
  57 static ssize_t
  58 stream_array_fetch(stream_t *str)
  59 {
  60         ASSERT(str->s_status & STREAM_OPEN);
  61         ASSERT(str->s_type.LA.s_cur_index < str->s_type.LA.s_array_size);
  62
  63         if (++str->s_type.LA.s_cur_index == str->s_type.LA.s_array_size - 1)
  64                 stream_set(str, STREAM_EOS_REACHED);
  65
  66         copy_line_rec(str->s_type.LA.s_array[str->s_type.LA.s_cur_index],
  67             &str->s_current);
  68
  69         return (NEXT_LINE_COMPLETE);
  70 }
  71
  72 /*ARGSUSED*/
  73 static int
  74 stream_array_is_closable(stream_t *str)
  75 {
  76         /*
  77          * Array streams are not closable.  That is, there is no open file
  78          * descriptor directly associated with an array stream.
  79          */
  80         return (0);
  81 }
  82
  83 static int
  84 stream_array_close(stream_t *str)
  85 {
  86         stream_unset(str, STREAM_OPEN | STREAM_PRIMED);
  87
  88         return (1);
  89 }
  90
  91 static int
  92 stream_array_free(stream_t *str)
  93 {
  94         /*
  95          * It's now safe for us to close the various streams backing the array
  96          * stream's data.
  97          */
  98         stream_unset(str, STREAM_PRIMED | STREAM_NOT_FREEABLE);
  99
 100         return (1);
 101 }
 102
 103 static int
 104 stream_array_eos(stream_t *str)
 105 {
 106         int retval = 0;
 107
 108         if (str == NULL || str->s_status & STREAM_EOS_REACHED)
 109                 return (1);
 110
 111         if (str->s_type.LA.s_cur_index + 1 >= str->s_type.LA.s_array_size) {
 112                 retval = 1;
 113                 stream_set(str, STREAM_EOS_REACHED);
 114         }
 115
 116         return (retval);
 117 }
 118
 119 /*ARGSUSED*/
 120 static void
 121 stream_array_release_line(stream_t *str)
 122 {
 123 }
 124
 125 const stream_ops_t stream_array_ops = {
 126         stream_array_is_closable,
 127         stream_array_close,
 128         stream_array_eos,
 129         stream_array_fetch,
 130         NULL,
 131         stream_array_free,
 132         NULL,
 133         stream_array_prime,
 134         NULL,
 135         stream_array_release_line,
 136         NULL,
 137         NULL
 138 };