环形数组逆向遍历

 

 

 

环形数组逆向遍历

#include <stdio.h>
#include <string.h>

#define shell_printf_greep(format,...) printf("\033[42;37m"format"\033[0m",  ##__VA_ARGS__) 
#define shell_printf_red(format,...) printf("\033[41;37m"format"\033[0m",  ##__VA_ARGS__) 

typedef struct _latest_pushid{
#define POOL_LATEST_PUSHID_MAX   10
    unsigned int is_full; // 是否已完成环形数组的第一遍存储
    unsigned int next_index;
    unsigned int pushid[POOL_LATEST_PUSHID_MAX];
}latest_pushid_t;

latest_pushid_t g_latest_pushid = {0};


#if 0
/* 
   新来一条消息, 查询是否曾经收过该pushid消息, 未收过则将此pushid放入池中
   return 1: 曾经收过此pushid消息
0: 未曾收过此pushid消息
*/
int is_message_repeat(const unsigned int pushid){
    int index = 0;

    int index_begin = (0 >= g_latest_pushid.next_index) ? (POOL_LATEST_PUSHID_MAX - 1) : (g_latest_pushid.next_index - 1);
    int index_end = (0 == g_latest_pushid.is_full) ? 0 : g_latest_pushid.next_index;

    //printf("index_begin=%d, index_end=%d\r\n", index_begin, index_end);

    if (0 == g_latest_pushid.is_full && POOL_LATEST_PUSHID_MAX - 1 == index_begin)
    {
        //        printf("empth array\r\n");
    }
    else if (1 == g_latest_pushid.is_full && POOL_LATEST_PUSHID_MAX - 1 == index_begin)
    {
        for (index = POOL_LATEST_PUSHID_MAX - 1; index >=0; index--)
        {
            //            printf("for index=%d\r\n", index);
            if (pushid == g_latest_pushid.pushid[index]){
                return 1;
            }
        }
    }
    else
    {
        int touch_begin = 0;

        for (index = index_begin; (0 == touch_begin) || (1 == touch_begin && index >= index_end); ){
            //            printf("for index=%d, touch_begin=%d\r\n", index, touch_begin);
            if (pushid == g_latest_pushid.pushid[index]){
                return 1;
            }

            if ( 0 == index ){
                touch_begin = 1;
            }

            index--;
            if (0 > index)
            {
                if (0 == g_latest_pushid.is_full)
                    break;
                else
                    index = POOL_LATEST_PUSHID_MAX - 1;
            }

            //            usleep(100 * 1000);

        }
    }

    g_latest_pushid.pushid[g_latest_pushid.next_index] = pushid;

    g_latest_pushid.next_index++;

    if(POOL_LATEST_PUSHID_MAX <= g_latest_pushid.next_index){
        g_latest_pushid.is_full = 1;
    }

    g_latest_pushid.next_index = g_latest_pushid.next_index % POOL_LATEST_PUSHID_MAX;

    return 0;
}

#elif 1  // 此方法最好
int is_message_repeat(const unsigned int pushid){
    int index = 0;
    int index_array = 0;


    int index_max = (0 == g_latest_pushid.is_full) ? g_latest_pushid.next_index : POOL_LATEST_PUSHID_MAX;
    for (index = 0; index < index_max; index++){
        index_array = (g_latest_pushid.next_index - 1 - index + POOL_LATEST_PUSHID_MAX) % POOL_LATEST_PUSHID_MAX;
        printf("for index=%d, index_array=%d\r\n", index, index_array);
        if (pushid == g_latest_pushid.pushid[index_array]){
            return 1;
        }
    }

    g_latest_pushid.pushid[g_latest_pushid.next_index] = pushid;

    // make the next_index
    g_latest_pushid.next_index++;

    if(POOL_LATEST_PUSHID_MAX <= g_latest_pushid.next_index){
        g_latest_pushid.is_full = 1;
    }

    g_latest_pushid.next_index = g_latest_pushid.next_index % POOL_LATEST_PUSHID_MAX;

    return 0;
}
#else
int is_message_repeat(const unsigned int pushid){
    int index = 0;
    int index_array[POOL_LATEST_PUSHID_MAX];

    for (index = 0; index < POOL_LATEST_PUSHID_MAX; index++){
        index_array[index] = (g_latest_pushid.next_index - 1 - index + POOL_LATEST_PUSHID_MAX) % POOL_LATEST_PUSHID_MAX;
    }

    int end_index_of_index_array = (0 == g_latest_pushid.is_full) ? g_latest_pushid.next_index : POOL_LATEST_PUSHID_MAX;
    for (index = 0; index < end_index_of_index_array; index++){
        if (pushid == g_latest_pushid.pushid[index_array[index]]){
            return 1;
        }
    }

    g_latest_pushid.pushid[g_latest_pushid.next_index] = pushid;

    // make the next_index
    g_latest_pushid.next_index++;

    if(POOL_LATEST_PUSHID_MAX <= g_latest_pushid.next_index){
        g_latest_pushid.is_full = 1;
    }

    g_latest_pushid.next_index = g_latest_pushid.next_index % POOL_LATEST_PUSHID_MAX;

    return 0;
}

#endif

int print_circle_array(){
    int index = 0;

    for (index = 0; index < POOL_LATEST_PUSHID_MAX; index++)
        printf("%u, ", g_latest_pushid.pushid[index]);

    printf("\r\n");

}

int main(int argc, char *argv[])
{
    int index = 0;

    int a[POOL_LATEST_PUSHID_MAX] = {0}; 

    for ( index = 100; ; index++){
        int is_in = 0;
        int j = 0;

        int ask = index;
        is_in = is_message_repeat(index); 
        printf("ask=%d, is_in=", ask);
        
        if (1 == is_in)
            shell_printf_greep("Yes.");
        else
            shell_printf_red("No");

        printf("\r\n");

        print_circle_array();

        for (j = 0; j<POOL_LATEST_PUSHID_MAX; j++)
        {
            ask = g_latest_pushid.pushid[j];
            is_in = is_message_repeat(ask); 
        //    printf("ask=%d, is_in=%s.\r\n", ask, 1 == is_in ? "Yes" : "No");
            printf("ask=%d, is_in=", ask);

            if (1 == is_in)
                shell_printf_greep("Yes.");
            else
                shell_printf_red("No");

        printf("\r\n");
            print_circle_array();

        }

        sleep(1);
    }
    return 0;
}