| 1 | /*
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| 2 | * Copyright (c) 1988, 1989, 1990, 1993
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| 3 | * The Regents of the University of California. All rights reserved.
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| 4 | *
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| 5 | * This code is derived from software contributed to Berkeley by
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| 6 | * Adam de Boor.
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| 7 | *
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| 8 | * Redistribution and use in source and binary forms, with or without
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| 9 | * modification, are permitted provided that the following conditions
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| 10 | * are met:
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| 11 | * 1. Redistributions of source code must retain the above copyright
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| 12 | * notice, this list of conditions and the following disclaimer.
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| 13 | * 2. Redistributions in binary form must reproduce the above copyright
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| 14 | * notice, this list of conditions and the following disclaimer in the
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| 15 | * documentation and/or other materials provided with the distribution.
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| 16 | * 3. All advertising materials mentioning features or use of this software
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| 17 | * must display the following acknowledgement:
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| 18 | * This product includes software developed by the University of
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| 19 | * California, Berkeley and its contributors.
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| 20 | * 4. Neither the name of the University nor the names of its contributors
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| 21 | * may be used to endorse or promote products derived from this software
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| 22 | * without specific prior written permission.
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| 23 | *
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| 24 | * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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| 25 | * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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| 26 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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| 27 | * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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| 28 | * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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| 29 | * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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| 30 | * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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| 31 | * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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| 32 | * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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| 33 | * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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| 34 | * SUCH DAMAGE.
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| 35 | *
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| 36 | * $FreeBSD: src/usr.bin/make/lst.lib/lstDeQueue.c,v 1.6 1999/08/28 01:03:48 peter Exp $
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| 37 | */
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| 38 |
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| 39 | #ifndef lint
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| 40 | static char sccsid[] = "@(#)lstDeQueue.c 8.1 (Berkeley) 6/6/93";
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| 41 | #endif /* not lint */
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| 42 |
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| 43 | /*-
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| 44 | * LstDeQueue.c --
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| 45 | * Remove the node and return its datum from the head of the list
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| 46 | */
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| 47 |
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| 48 | #include "lstInt.h"
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| 49 |
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| 50 | /*-
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| 51 | *-----------------------------------------------------------------------
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| 52 | * Lst_DeQueue --
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| 53 | * Remove and return the datum at the head of the given list.
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| 54 | *
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| 55 | * Results:
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| 56 | * The datum in the node at the head or (ick) NIL if the list
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| 57 | * is empty.
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| 58 | *
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| 59 | * Side Effects:
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| 60 | * The head node is removed from the list.
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| 61 | *
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| 62 | *-----------------------------------------------------------------------
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| 63 | */
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| 64 | ClientData
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| 65 | Lst_DeQueue (l)
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| 66 | Lst l;
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| 67 | {
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| 68 | ClientData rd;
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| 69 | register ListNode tln;
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| 70 |
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| 71 | tln = (ListNode) Lst_First (l);
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| 72 | if (tln == NilListNode) {
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| 73 | return ((ClientData) NIL);
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| 74 | }
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| 75 |
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| 76 | rd = tln->datum;
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| 77 | if (Lst_Remove (l, (LstNode)tln) == FAILURE) {
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| 78 | return ((ClientData) NIL);
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| 79 | } else {
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| 80 | return (rd);
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| 81 | }
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| 82 | }
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| 83 |
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