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// Name: Logan Gillespie
// Class: CST 126
// Date: 5/16/24
// Assignment: Homework 2
#include <iostream>
#include <fstream>
#include <sstream>
using namespace std;
string encodeFileToBase64(const string& filename);
string decodeBase64(const string& encoded);
bool decodeBase64ToFile(const string& base64Data, const string& filename);
int main()
{
int choice = 0;
do {
cout << "Welcome to my program! Here are your options:" << endl;
cout << "0. Quit" << endl;
cout << "1. Encode File to Base64" << endl;
cout << "2. Decode Base64 to File" << endl;
cin >> choice;
switch (choice) {
case 1:
{
string filename;
cout << "Enter input filename: ";
std::cin.clear();
std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
getline(cin, filename);
string base64Data = encodeFileToBase64(filename);
cout << "Base64 Encoded Data:\n" << base64Data << endl;
break;
}
case 2:
{
string base64Data;
cout << "Enter Base64 encoded data: ";
cin >> base64Data;
string filename;
cout << "Enter output filename: ";
std::cin.clear();
std::cin.ignore(std::numeric_limits<std::streamsize>::max(), '\n');
getline(cin, filename);
if (decodeBase64ToFile(base64Data, filename)) {
cout << "File successfully decoded and written: " << filename << endl;
}
else {
cout << "Failed to decode and write file." << endl;
}
break;
}
}
} while (choice != 0);
}
string encodeFileToBase64(const string& filename) {
ifstream file(filename, ios::binary | ios::ate);
if (!file.is_open()) {
cout << "Error: Unable to open file " << filename << endl;
return "";
}
// Get file size
streamsize fileSize = file.tellg();
file.seekg(0, ios::beg);
// Read file into buffer
char* buffer = new char[fileSize];
file.read(buffer, fileSize);
// Base64 encoding table
const string base64_chars =
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/";
// Encode buffer to Base64
stringstream encoded;
int val = 0, valb = -6;
for (int i = 0; i < fileSize; i++) {
unsigned char c = buffer[i];
val = (val << 8) + c;
valb += 8;
while (valb >= 0) {
encoded << base64_chars[(val >> valb) & 0x3F];
valb -= 6;
}
}
// Handle any remaining bits and add padding
if (valb > -6) {
encoded << base64_chars[((val << 8) >> (valb + 8)) & 0x3F];
}
while (encoded.str().size() % 4 != 0) {
encoded << '=';
}
/*// Calculate padding
int padding = (3 - (fileSize % 3)) % 3;
// Add padding with '='
while (padding--) {
encoded << '=';
}*/
delete[] buffer;
file.close();
return encoded.str();
}
string decodeBase64(const string& encoded) {
// Base64 decoding table
const string base64_chars =
"ABCDEFGHIJKLMNOPQRSTUVWXYZ"
"abcdefghijklmnopqrstuvwxyz"
"0123456789+/";
string decoded;
int val = 0, valb = -8;
for (char c : encoded) {
if (c == '=') break;
if (base64_chars.find(c) == string::npos) {
cout << "Error: Invalid Base64 character detected!" << endl;
return "";
}
val = (val << 6) + base64_chars.find(c);
valb += 6;
if (valb >= 0) {
decoded.push_back(char((val >> valb) & 0xFF));
valb -= 8;
}
}
return decoded;
}
bool decodeBase64ToFile(const string& base64Data, const string& filename) {
ofstream file(filename, ios::binary);
if (!file.is_open()) {
cout << "Error: Unable to create file " << filename << endl;
return false;
}
string decodedData = decodeBase64(base64Data);
if (decodedData.empty()) {
cout << "Error: Failed to decode Base64 data" << endl;
return false;
}
file.write(decodedData.c_str(), decodedData.size());
file.close();
return true;
}
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