mem中需找特定字符

memstr

//find 'substr' from a fixed-length buffer 
//('full_data' will be treated as binary data buffer)
//return NULL if not found
char* memstr(char* full_data, int full_data_len, char* substr)
{
    if (full_data == NULL || full_data_len <= 0 || substr == NULL) {
        return NULL;
    }

    if (*substr == '') {
        return NULL;
    }

    int sublen = strlen(substr);

    int i;
    char* cur = full_data;
    int last_possible = full_data_len - sublen + 1;
    for (i = 0; i < last_possible; i++) {
        if (*cur == *substr) {
            //assert(full_data_len - i >= sublen);
            if (memcmp(cur, substr, sublen) == 0) {
                //found
                return cur;
            }
        }
        cur++;
    }

    return NULL;
}

memfind

char* memstr(char* full_data, int full_data_len, char* substr, int substr_len)
{

}