平均运营ARM NEON(average operation ARM NEON)

 您通过修改std::string的字符超过其末尾（均为nom[j] = lines）来调用未定义的行为。 您应该使用其push_back成员函数，以及直接连接字符串而不是使用char缓冲区。 
 
 另外，你只分配一个字符，然后strcpy方式通过它...并泄漏它的指针。 
 
 此外，您使用幻数而不是字符常量\r 。 
 
 这是一个更正（更简单）的版本： 
 
string getRuta(int i, char const* buffer, string directorio) {
    string nom;
    char c;
    do {
        c = buffer[i];
        nom.push_back(c);
        i++;
    } while (buffer[i] != '\r');

    string ruta = directorio + nom;
    printf("%s\n",ruta.c_str());
    return ruta;
}

You're invoking undefined behavior by modifying a std::string's characters past its end (both nom[j] = lines). You should use its push_back member function instead, as well as concatenate your strings directly instead of using a char buffer.
 
In addition, you only allocate one character, then strcpy way past it... and leak its pointer.
 
Also, you use a magic number instead of the character constant \r.
 
Here is a corrected (and much simpler) version:
 
string getRuta(int i, char const* buffer, string directorio) {
    string nom;
    char c;
    do {
        c = buffer[i];
        nom.push_back(c);
        i++;
    } while (buffer[i] != '\r');

    string ruta = directorio + nom;
    printf("%s\n",ruta.c_str());
    return ruta;
}