Path: chuka.playstation.co.uk!scea!peter_alau@playstation.sony.com
From: "Antony Arciuolo" <antony.arciuolo@mail.trincoll.edu>
Newsgroups: scee.yaroze.programming.2d_graphics
Subject: A simple Queue
Date: Wed, 23 Sep 1998 17:40:28 -0400
Organization: SCEA News Server
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Message-ID: <6ubp2u$1mg5@scea>
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I'm trying to make a Queue, that's all, but when I typedef the type of the
Queue (implemented as an array) the system freezes. Shorts work fine, chars
work fine, but I will be using this Queue for long pointers, and it just
isn't working.

Here is Queue.h:

#ifndef QUEUE_H
#define QUEUE_H


// INCLUDES -------------------------------------------------

#include <assert.h>
#include <stdlib.h>


// DEFINITIONS ----------------------------------------------

#define QUEUE_DEBUG    (1)
#define QUEUE_RUN_MAIN (0)

#define QUEUE_SIZEOF   (10)
#define QUEUE_OVERHEAD ( 3)
#define QUEUE_HEAD     (QUEUE_SIZEOF)
#define QUEUE_TAIL     (QUEUE_SIZEOF + 1)
#define QUEUE_COUNTER  (QUEUE_SIZEOF + 2)

#define QUEUE_NULL (-1)

typedef long QUEUE_DataType;
typedef QUEUE_DataType QUEUE[QUEUE_SIZEOF + QUEUE_OVERHEAD];


// PROTOTYPES -----------------------------------------------

void QUEUE_Init(QUEUE *q);
void QUEUE_Push(QUEUE *q, QUEUE_DataType item);
QUEUE_DataType QUEUE_Read(QUEUE *q);
QUEUE_DataType QUEUE_Pop(QUEUE *q);
short QUEUE_IsEmpty(QUEUE *q);

#if (QUEUE_DEBUG)
void QTest(void);
void QUEUE_Dump(QUEUE *q);
#endif



Here is Queue.c:

#include "Queue.h"

void QUEUE_Init(QUEUE *q)
{
 short i;
 for (i = 0; i < QUEUE_SIZEOF; i++)
 {
#if (QUEUE_DEBUG)
 printf("Init'ing %d to %d\n", i, QUEUE_NULL);
#endif
  *q[i] = QUEUE_NULL;

#if (QUEUE_DEBUG)
 printf("*q[%d] is %d\n", i, *q[i]);
#endif
 }

 *q[QUEUE_HEAD]    = 0;
 *q[QUEUE_TAIL]    = 0;
 *q[QUEUE_COUNTER] = 0;
}

void QUEUE_Push(QUEUE *q, QUEUE_DataType item)
{
 short tail;

 tail = (short)(*q[QUEUE_TAIL]);

#if (QUEUE_DEBUG)
 printf("QPush(%p, %d): T:%d\n", q, item, tail);
#endif

 if (*q[QUEUE_COUNTER] < QUEUE_SIZEOF)
 {
  if (*q[QUEUE_COUNTER] != 0)
   *q[QUEUE_TAIL] = (*q[QUEUE_TAIL] + 1) % QUEUE_SIZEOF;

  *q[*q[QUEUE_TAIL]] = item;
  *q[QUEUE_COUNTER]  = *q[QUEUE_COUNTER] + 1;
 }

 else printf("QPush Queue Full! (%p) item: %d\n", q, item);
}

QUEUE_DataType QUEUE_Read(QUEUE *q)
{
#if (QUEUE_DEBUG)
 printf("QRead(%p): H:%d item: %d\n", q, *q[QUEUE_HEAD],
*q[*q[QUEUE_HEAD]]);
#endif
 return (*q[*q[QUEUE_HEAD]]);
}

QUEUE_DataType QUEUE_Pop(QUEUE *q)
{
 QUEUE_DataType x;

#if (QUEUE_DEBUG)
 printf("QPop(%p): H:%d item: %d\n", q, *q[QUEUE_HEAD], *q[*q[QUEUE_HEAD]]);
#endif

 if (*q[QUEUE_COUNTER] > 0)
 {
  x = *q[*q[QUEUE_HEAD]];

  *q[QUEUE_HEAD] = (*q[QUEUE_HEAD] + 1) % QUEUE_SIZEOF;
  *q[QUEUE_COUNTER] = *q[QUEUE_COUNTER] - 1;

  return x;
 }

 else
 {
  printf("QPop Queue Empty! (%p)\n", q);
  return (QUEUE_NULL);
 }
}

short QUEUE_IsEmpty(QUEUE *q)
{
 return (!(*q[QUEUE_COUNTER]));
}

#if (QUEUE_DEBUG)
void QUEUE_Dump(QUEUE *q)
{
 short i;

 printf("Queue %p:\n", q);

 for (i = 0; i < (QUEUE_SIZEOF + QUEUE_OVERHEAD); i++)
 {
  printf("%d: %d, ", i, *(q[i]));
 }

 printf("\n\n");
}

void QTest(void)
{
 QUEUE q;
 short i;
 QUEUE_Init(&q);

 if (QUEUE_IsEmpty(&q)) printf("1. Queue is Empty!\n");

 for (i = 0; i < QUEUE_SIZEOF; i++)
  QUEUE_Push(&q, i);

 if (QUEUE_IsEmpty(&q)) printf("2. Queue is Empty!\n");

 QUEUE_Push(&q, 12);

 for (i = 0; i < QUEUE_SIZEOF; i++)
  printf("Pop item %d: %d\n" , i, QUEUE_Pop(&q));

 if (QUEUE_IsEmpty(&q)) printf("3. Queue is Empty!\n");

 QUEUE_Pop(&q);

 QUEUE_Dump(&q);
}
#endif

#if (QUEUE_RUN_MAIN)
void main(void)
{
 QUEUE q;
 short i;
 QUEUE_Init(&q);

 if (QUEUE_IsEmpty(&q)) printf("1. Queue is Empty!\n");

 for (i = 0; i < QUEUE_SIZEOF; i++)
  QUEUE_Push(&q, i);

 if (QUEUE_IsEmpty(&q)) printf("2. Queue is Empty!\n");

 QUEUE_Push(&q, 12);

 for (i = 0; i < QUEUE_SIZEOF; i++)
  printf("Pop item %d: %d\n" , i, QUEUE_Pop(&q));

 if (QUEUE_IsEmpty(&q)) printf("3. Queue is Empty!\n");

 QUEUE_Pop(&q);

 QUEUE_Dump(&q);
}
#endif

#endif


Can anyone help? Please! I am testing this in my main by this method:


void main(void)
{
    QTest();
    return; // I just want to test the Queue

    ... The rest of my code ...

}


- Tony