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51 lines
930 B
51 lines
930 B
28 years ago
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/* insque(3C) routines
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This file is in the public domain. */
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/*
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NAME
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insque, remque -- insert, remove an element from a queue
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SYNOPSIS
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struct qelem {
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struct qelem *q_forw;
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struct qelem *q_back;
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char q_data[];
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};
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void insque (struct qelem *elem, struct qelem *pred)
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void remque (struct qelem *elem)
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DESCRIPTION
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Routines to manipulate queues built from doubly linked lists.
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The insque routine inserts ELEM in the queue immediately after
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PRED. The remque routine removes ELEM from its containing queue.
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*/
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struct qelem {
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struct qelem *q_forw;
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struct qelem *q_back;
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};
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void
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insque (elem, pred)
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struct qelem *elem;
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struct qelem *pred;
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{
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elem -> q_forw = pred -> q_forw;
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pred -> q_forw -> q_back = elem;
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elem -> q_back = pred;
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pred -> q_forw = elem;
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}
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void
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remque (elem)
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struct qelem *elem;
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{
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elem -> q_forw -> q_back = elem -> q_back;
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elem -> q_back -> q_forw = elem -> q_forw;
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}
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