0x0 Base64介绍

Base64用于二进制转为字符串，编码后空间大1/3左右。

0x1 代码实现

h文件

class Base64Crypt {
public:
    static int Encode(const std::string& input, std::string& output);
    static int Decode(const std::string& input, std::string& output);
};

cpp文件

int Base64Crypt::Decode(const std::string &input, std::string &output) {
    if (input.empty())
        return -1;

    BIO* b64 = BIO_new(BIO_f_base64());
    if (b64) {
        int buf_len = input.length();
        char* buf = new char[buf_len];
        if (buf) {
            BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL);
            BIO* bmem = BIO_new_mem_buf(const_cast<char*>(input.c_str()), input.length());
            if (bmem) {
                bmem = BIO_push(b64, bmem);
                int len = BIO_read(bmem, buf, buf_len);
                if (len > 0)
                    output = std::string(buf, len);
            }
            delete[] buf;
        }
        BIO_free_all(b64);
    }
    return 0;
}

int Base64Crypt::Encode(const std::string &input, std::string &output) {
    if (input.empty())
        return -1;

    BIO* b64 = BIO_new(BIO_f_base64());
    if (b64) {
        BIO_set_flags(b64, BIO_FLAGS_BASE64_NO_NL);
        BIO* bmem = BIO_new(BIO_s_mem());
        if (bmem) {
            b64 = BIO_push(b64, bmem);
            BIO_write(b64, input.c_str(), input.length());
            BIO_flush(b64);
            BUF_MEM* buf_mem = NULL;
            BIO_get_mem_ptr(b64, &buf_mem);
            if (buf_mem)
                output = std::string(buf_mem->data, buf_mem->length);
        }
        BIO_free_all(b64);
    }
    return 0;
}