54 lines
1.6 KiB
C
54 lines
1.6 KiB
C
/* Copyright (C) 1992-2017 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<http://www.gnu.org/licenses/>. */
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#include <stddef.h>
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#include <search.h>
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/* Insert ELEM into a doubly-linked list, after PREV. */
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void
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insque (void *elem, void *prev)
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{
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if (prev == NULL)
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{
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((struct qelem *) elem)->q_forw = NULL;
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((struct qelem *) elem)->q_back = NULL;
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}
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else
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{
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struct qelem *next = ((struct qelem *) prev)->q_forw;
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((struct qelem *) prev)->q_forw = (struct qelem *) elem;
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if (next != NULL)
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next->q_back = (struct qelem *) elem;
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((struct qelem *) elem)->q_forw = next;
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((struct qelem *) elem)->q_back = (struct qelem *) prev;
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}
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}
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/* Unlink ELEM from the doubly-linked list that it is in. */
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void
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remque (void *elem)
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{
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struct qelem *next = ((struct qelem *) elem)->q_forw;
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struct qelem *prev = ((struct qelem *) elem)->q_back;
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if (next != NULL)
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next->q_back = prev;
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if (prev != NULL)
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prev->q_forw = (struct qelem *) next;
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}
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