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typedef struct CmdInfo
{
    char * cmd;
    char * desc;
    void (*handler)();
}tCmdInfo;

tLinkTable * pLinkTable = NULL;
tDataNode * head = NULL;

tCmdInfo cmdInfo[CMD_NUM] =
{
    {"help", "this is help cmd", help},
    {"read", "this is read cmd", read},
    {"write", "this is write cmd", write},
    {"get", "this is get cmd", get},
    {"pull", "this is pull cmd", pull},
    {"push", "this is push cmd", push},
    {"compare", "this is compare cmd", compare},
    {"put", "this is put cmd", put},
    {"quit", "this is quit cmd", quit}
};

/*
 * Initialize the pLinkTable with the menu command
 */
void InitMenuTable(tLinkTable * pLinkTable);

int main()
{
    pLinkTable = CreateLinkTable();
    if(NULL == pLinkTable)
    {
        printf("CreateLinkTable Error...\n");
        exit(1);
    }
    InitMenuTable(pLinkTable);
    head = (tDataNode *)pLinkTable->pHead;

    char cCmd[CMD_MAX_LEN];
    while(1)
    {
        printf("Input a cmd > ");
        scanf("%s", cCmd);
        tDataNode *p = FindCmd(head, cCmd);
        if (NULL == p)
        {
            printf("Undefined command...\n");
            continue;
        }
        printf("%s - %s\n", p->cmd, p->desc);
        if(NULL != p->handler)
        {
            p->handler();
        }
    }
    return 0;
}

/*
 * Initialize the pLinkTable with the menu command
 */
void InitMenuTable(tLinkTable * pLinkTable)
{
    for(int i = 0; i < CMD_NUM; i++)
    {
        tDataNode * pNode = (tDataNode *)malloc(sizeof(tDataNode));
        if(NULL == pNode)
        {
            printf("malloc Error...\n");
            exit(1);
        }
        pNode->cmd = (cmdInfo[i]).cmd;
        pNode->desc = (cmdInfo[i]).desc;
        pNode->handler = (cmdInfo[i]).handler;
        if(1 == AddLinkTableNode(pLinkTable, (tLinkTableNode *) pNode))
        {
            printf("AddLinkTableNode Error...\n");
            exit(1);
        }
    }
}

/*
 * Create a LinkTable
 * return value: If success, return the poiner points to the created LinkTable, otherwise return NULL
 */
tLinkTable * CreateLinkTable()
{
    tLinkTable * p = (tLinkTable *)malloc(sizeof(tLinkTable));
    if(NULL == p)
        return NULL;
    p->pHead = NULL;
    p->pTail = NULL;
    p->sumOfNode = 0;
    return p;
}

/*
 * Delete a LinkTable, and free the memory
 * return value: Always zero
 */
int DeleteLinkTable(tLinkTable * pLinkTable)
{
    if(NULL == pLinkTable)
        return 0;
    tLinkTableNode * pNode = pLinkTable->pHead;
    tLinkTableNode * pHead = pNode;
    while(NULL != pNode)
    {
        pHead = pHead->pNext;
        free(pNode);
        pNode = pHead;
    }
    free(pLinkTable);
    return 0;
}

/*
 * Add a LinkTableNode to LinkTable
 * return value: If success, return zero, otherwise return one
 */
int AddLinkTableNode(tLinkTable * pLinkTable, tLinkTableNode * pNode)
{
    if((NULL == pLinkTable) || (NULL == pNode))
        return 1;
    tLinkTableNode * pHead = pLinkTable->pHead;
    tLinkTableNode * pTail = pLinkTable->pTail;

    pNode->pNext = NULL;
    if(NULL == pHead)
    {
        pLinkTable->pHead = pLinkTable->pTail = pNode;
    }
    else
    {
        pLinkTable->pTail->pNext = pNode;
        pLinkTable->pTail = pNode;
    }
    pLinkTable->sumOfNode += 1;
    return 0;
}