1、在strings中查找key的位置

来源：

BusyBox-1.37.0    index_in_strings()

数据结构：

static const char keywords[] __attribute__((aligned(1))) = "bs\0""count\0""seek\0""skip\0""if\0""of\0";

算法：

int index_in_strings(const char *strings, const char *key)
{
    int j, idx = 0;

    while(*strings) 
    {
        /* Do we see "key\0" at current position in strings? */
        for(j = 0; *strings == key[j]; ++j) 
        {
            if(*strings++ == '\0') 
            {
                return idx; /* yes */
            }
        }
        /* No.  Move to the start of the next string. */
        while(*strings++ != '\0')
        {
            continue;
        }
        idx++;
    }
    return -1;
}