sort/common/streams_array.c

	streams_array.c revision 7c478bd95313f5f23a4c958a745db2134aa03244
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */
/*
 * Copyright 2004 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

#pragma ident   "%Z%%M% %I% %E% SMI"

#include "streams_array.h"
#include "streams_common.h"

/*
 * Single-byte character memory map-based streams implementation
 */

static int
stream_array_prime(stream_t *str)
{
    ASSERT((str->s_status & STREAM_SOURCE_MASK) == STREAM_ARRAY);

    str->s_type.LA.s_cur_index = MIN(0, str->s_type.LA.s_array_size - 1);
    if (str->s_type.LA.s_cur_index >= 0)
        copy_line_rec(
            str->s_type.LA.s_array[str->s_type.LA.s_cur_index],
            &str->s_current);
    else {
        stream_set(str, STREAM_EOS_REACHED);
        stream_unset(str, STREAM_PRIMED);
        return (PRIME_FAILED_EMPTY_FILE);
    }

    stream_set(str, STREAM_PRIMED);

    return (PRIME_SUCCEEDED);
}

static ssize_t
stream_array_fetch(stream_t *str)
{
    ASSERT(str->s_status & STREAM_OPEN);
    ASSERT(str->s_type.LA.s_cur_index < str->s_type.LA.s_array_size);

    if (++str->s_type.LA.s_cur_index == str->s_type.LA.s_array_size - 1)
        stream_set(str, STREAM_EOS_REACHED);

    copy_line_rec(str->s_type.LA.s_array[str->s_type.LA.s_cur_index],
        &str->s_current);

    return (NEXT_LINE_COMPLETE);
}

/*ARGSUSED*/
static int
stream_array_is_closable(stream_t *str)
{
    /*
     * Array streams are not closable.  That is, there is no open file
     * descriptor directly associated with an array stream.
     */
    return (0);
}

static int
stream_array_close(stream_t *str)
{
    stream_unset(str, STREAM_OPEN | STREAM_PRIMED);

    return (1);
}

static int
stream_array_free(stream_t *str)
{
    /*
     * It's now safe for us to close the various streams backing the array
     * stream's data.
     */
    stream_unset(str, STREAM_PRIMED | STREAM_NOT_FREEABLE);

    return (1);
}

static int
stream_array_eos(stream_t *str)
{
    int retval = 0;

    if (str == NULL || str->s_status & STREAM_EOS_REACHED)
        return (1);

    if (str->s_type.LA.s_cur_index + 1 >= str->s_type.LA.s_array_size) {
        retval = 1;
        stream_set(str, STREAM_EOS_REACHED);
    }

    return (retval);
}

/*ARGSUSED*/
static void
stream_array_release_line(stream_t *str)
{
}

const stream_ops_t stream_array_ops = {
    stream_array_is_closable,
    stream_array_close,
    stream_array_eos,
    stream_array_fetch,
    NULL,
    stream_array_free,
    NULL,
    stream_array_prime,
    NULL,
    stream_array_release_line,
    NULL,
    NULL
};