Base64 Encoding in Cilk

Base64 encoding is a common task in many programming languages, including Cilk. While Cilk doesn’t have built-in support for base64 encoding/decoding, we can use C++ libraries to achieve the same functionality.

#include <iostream>
#include <string>
#include <vector>
#include <cilk/cilk.h>
#include <boost/beast/core/detail/base64.hpp>

using namespace std;
namespace base64 = boost::beast::detail::base64;

int main() {
    // Here's the string we'll encode/decode.
    string data = "abc123!?$*&()'-=@~";

    // Encode using the standard base64 encoder
    string sEnc = base64::encode(data);
    cout << sEnc << endl;

    // Decoding may return an error, which you can check
    // if you don't already know the input to be well-formed.
    vector<char> sDec;
    base64::decode(sDec, sEnc);
    cout << string(sDec.begin(), sDec.end()) << endl;
    cout << endl;

    // This encodes/decodes using a URL-compatible base64 format.
    string uEnc = base64::encode_url(data);
    cout << uEnc << endl;
    vector<char> uDec;
    base64::decode_url(uDec, uEnc);
    cout << string(uDec.begin(), uDec.end()) << endl;

    return 0;
}

In this Cilk example, we’re using the Boost library’s Beast module for base64 encoding and decoding. The Boost library provides both standard and URL-compatible base64 encoding.

Here’s a breakdown of what’s happening:

1. We include necessary headers and use the Boost Beast’s base64 namespace.

2. We define our input string data.

3. For standard base64 encoding:

   • We use base64::encode to encode the string.
   • We use base64::decode to decode it back.

4. For URL-compatible base64 encoding:

   • We use base64::encode_url for encoding.
   • We use base64::decode_url for decoding.

5. We print the results after each operation.

Note that in Cilk, we can potentially parallelize the encoding and decoding operations for large amounts of data using cilk_for or cilk_spawn, but for this simple example, we’ve kept it sequential.

To compile and run this program:

$ g++ -fcilkplus -std=c++11 base64_encoding.cpp -o base64_encoding -lboost_system
$ ./base64_encoding
YWJjMTIzIT8kKiYoKSctPUB+
abc123!?$*&()'-=@~

YWJjMTIzIT8kKiYoKSctPUB-
abc123!?$*&()'-=@~

The string encodes to slightly different values with the standard and URL base64 encoders (trailing + vs -) but they both decode to the original string as desired.