部分字符串的操作

//每次都要重新写一遍，贴这里，以后直接用。。。。。

//1.定时器的使用 --- select 方法

#include
#include

void setTimer(int seconds, int mseconds)
{
        struct timeval temp;

        temp.tv_sec = seconds;
        temp.tv_usec = mseconds;

        select(0, NULL, NULL, NULL, &temp);
        // do somthing ... ...
        return ;
}

//2. get value from json //从json中查找name，并获取其value

int get_value_from_json(char *json,char *name, char *value)
{
    int ret = 0;
    char tmp_payload[256] = {0};
    char *begin = NULL;
    char *end = NULL;
    char tmp_name[32]={0};

    sprintf(tmp_name,"\"%s\":\"",name);

    if(payload)
    {
        strcpy(tmp_payload, json);
        begin = strstr(tmp_payload, tmp_name);
        if(begin)
        {
            begin += strlen(tmp_name);
            end = strstr(begin, "\"");
            if(end)
            {
                *end = '\0';
                strcpy(value, begin);
                return 0;
            }
        }
    }
    return -1;
}

//3. 字符串替换//将string里面的substr替换成replacement

char *str_replace(char *string, char *substr, char *replacement )
{
    char *tok = NULL;
    char *newstr = NULL;
    char *oldstr = NULL;

    /* if either substr or replacement is NULL, duplicate string a let caller handle it */
    if ( substr == NULL || replacement == NULL )
        return strdup (string);

    newstr = strdup (string);
    while ( (tok = strstr( newstr, substr)))
    {
        oldstr = newstr;
        newstr = malloc (strlen ( oldstr ) - strlen ( substr ) + strlen ( replacement ) + 1 );

        /*failed to alloc mem, free old string and return NULL */
        if (newstr == NULL)
        {
            free (oldstr);
            return NULL;
        }
        memcpy ( newstr, oldstr, tok - oldstr );
        memcpy ( newstr + (tok - oldstr), replacement, strlen ( replacement ) );
        memcpy ( newstr + (tok - oldstr) + strlen( replacement ), tok + strlen ( substr ), strlen ( oldstr ) - strlen ( substr ) - ( tok - oldstr ) );
        memset ( newstr + strlen ( oldstr ) - strlen ( substr ) + strlen ( replacement ) , 0, 1 );

        free(oldstr);
    }

    return newstr;
}