anagram.c

基于嵌入式实时开发系统Tornado 2的工具使用内部培训资料

/* anagram.c - multitask string permutations demo */

#include "vxWorks.h"
#include "stdio.h"
#include "stdlib.h"
#include "string.h"
#include "taskLib.h"
#include "semLib.h"
#include "sysLib.h"
#include "wvLib.h"

#define ANAGRAM_MUTEX_OPTS SEM_Q_PRIORITY | SEM_DELETE_SAFE | SEM_INVERSION_SAFE

typedef struct anagramBase
    {
    SEM_ID mutex;
    char * string;
    int length;
    } ANAGRAM_BASE;

LOCAL ANAGRAM_BASE anagram;

int i = 0; /* count of number of modifications so far */

STATUS anagramInit
    (
    char * str
    )
    {
    /* Only create mutex if it hasn't been done yet...*/
    if (anagram.mutex == NULL)
        if ((anagram.mutex = semMCreate (ANAGRAM_MUTEX_OPTS))
             == NULL)
            return ERROR;

    if (str == NULL || strlen(str) == 0)
        return ERROR;

    /* Save string and length atomically */
    semTake (anagram.mutex, WAIT_FOREVER);
    anagram.string = str;
    anagram.length = strlen (str);
    semGive (anagram.mutex);
    printf ("\n\n");
    return OK;
    }

void anagramIt 
    (
    int delayTicks   /* Zero for default 1/4 second */
    )
    {
    int i1, i2;
    char temp;

    if (delayTicks <= 0)
	delayTicks = sysClkRateGet();

    FOREVER
        {
        if (semTake (anagram.mutex, WAIT_FOREVER) == ERROR)
            return;

        i1 = rand() % anagram.length;
        i2 = rand() % anagram.length;
        temp = anagram.string[i1];
        anagram.string[i1] = anagram.string[i2];
        anagram.string[i2] = temp;

	i++;

        printf ("(%s) '%s'\n",taskName(0), anagram.string);
        semGive (anagram.mutex);

        taskDelay (delayTicks);
        }
    }