52 lines
966 B
C
52 lines
966 B
C
/* Copyright (C) 2010, 2011 Tony Garnock-Jones. All rights reserved. */
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#include <stdlib.h>
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#include <string.h>
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#include <stdio.h>
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#include <assert.h>
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#include "dataq.h"
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#define QLINK(q,x) (*((void **)(((char *) x) + (q)->link_offset)))
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void enqueue(queue_t *q, void *x) {
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QLINK(q, x) = NULL;
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if (q->head == NULL) {
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q->head = x;
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} else {
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QLINK(q, q->tail) = x;
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}
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q->tail = x;
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q->count++;
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}
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void *dequeue(queue_t *q) {
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if (q->head == NULL) {
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return NULL;
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} else {
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void *x = q->head;
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q->head = QLINK(q, x);
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QLINK(q, x) = NULL;
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if (q->head == NULL) {
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q->tail = NULL;
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}
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q->count--;
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return x;
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}
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}
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void queue_append(queue_t *q1, queue_t *q2) {
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assert(q1->link_offset == q2->link_offset);
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if (q2->head != NULL) {
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if (q1->head != NULL) {
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QLINK(q1, q1->tail) = q2->head;
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} else {
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q1->head = q2->head;
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}
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q1->tail = q2->tail;
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q2->head = NULL;
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q2->tail = NULL;
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}
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}
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