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#pragma once
#include <fstream>
#include <zlib.h>
#include "Base64.hpp"
constexpr int CHUNK = 16384;
constexpr int WINDOW_BITS = 15;
//Returns true if it was able to open the given file for reading
bool IsFile(const std::string& filename) {
std::ifstream file(filename);
const bool ret = file.good();
file.close();
return ret;
}
//Reads the contents of a given file into a string
std::string FileToStr(const std::string& filename) {
std::ifstream file(filename, std::ios::binary);
if (!file.good())
return "";
std::string ret(std::istreambuf_iterator<char>(file), {});
file.close();
return ret;
}
//Writes the contents of a string to the given file
// returns false if it was unable to open the file
bool StrToFile(const std::string& filename, const std::string& data) {
std::ofstream ofile(filename, std::ios::binary);
if(!ofile.good())
return false;
ofile << data;
ofile.close();
return true;
}
//XORs each byte of a string reference
void Xor_Str(std::string& str, unsigned char key) {
for (auto& c : str) {
c = c^key;
}
}
std::string GZipDecompress(const std::string& in) {
//Initialize all members of strm to be 0
z_stream strm = {};
//Output buffer
char out[CHUNK];
//Holds return value
std::string final_output;
//Initialize GZip decompression; except on failure
if(inflateInit2(&strm, WINDOW_BITS + 16) != Z_OK)
throw(std::exception());
//Tell zlib where to find the data we want to decompress
strm.avail_in = in.size();
strm.next_in = (Bytef*)in.data();
do {
//Tell zlib where to store the decompressed output data
strm.avail_out = CHUNK;
strm.next_out = (Bytef*)out;
//Decompress our input data; except on failure
switch (inflate(&strm, Z_FINISH)) {
case Z_NEED_DICT:
throw(std::exception());
case Z_DATA_ERROR:
throw(std::exception());
case Z_MEM_ERROR:
throw(std::exception());
}
//How many bytes we received into our output buffer
unsigned int have = CHUNK - strm.avail_out;
//Append received data to our return string
final_output.append(reinterpret_cast<const char*>(out), have);
} while (strm.avail_out == 0);
//Clean up and return
inflateEnd(&strm);
return final_output;
}
std::string GZipCompress(const std::string& in) {
//Initialize all members of strm to be 0
z_stream strm = {};
//Output buffer
unsigned char out[CHUNK];
//Return value
std::string final_output;
//Initialize GZip compression; except on failure
if (deflateInit(&strm, Z_DEFAULT_COMPRESSION) != Z_OK)
throw(std::exception());
//Tell zlib where to find the data we want to compress
strm.avail_in = in.size();
strm.next_in = (Bytef*)in.data();
do {
//Tell zlib where to store the compressed output data
strm.avail_out = CHUNK;
strm.next_out = out;
//Compress our input data; except on failure
if(deflate(&strm, Z_FINISH) == Z_STREAM_ERROR)
throw(std::exception());
//How many bytes we received into our output buffer
unsigned int have = CHUNK - strm.avail_out;
//Append received data to our return string
final_output.append(reinterpret_cast<const char*>(out), have);
} while (strm.avail_out == 0);
//Clean up and return
deflateEnd(&strm);
return final_output;
}
/** @brief Decrypt GD save files or level data *
* @param in_data encrypted input data *
* @param xor11 whether or not the data should be xored with 11; *
* select true for gamesave or false for level data *
* @retval decrypted data **/
std::string Decrypt(const std::string& in_data, bool xor11) {
//Retun value
std::string ret = in_data;
//Xor with value 11 if nescessary
if(xor11)
Xor_Str(ret, 11);
//replace - with + and _ with /
for (auto& i : ret) {
if (i == '-')
i = '+';
if (i == '_')
i = '/';
}
//Decrypt with Base64
ret = base64::Decode(ret);
//Decompress with GZip
ret = GZipDecompress(ret);
//Return
return ret;
}
/** @brief Encrypt GD save files or level data *
* @param in_data decrypted input data *
* @param xor11 whether or not the data should be xored with 11; *
* select true for gamesave or false for level data *
* @retval encrypted data **/
std::string Encrypt(const std::string& in_data, bool xor11) {
//Calculate crc32 checksum and size
const uLong crc = crc32(0L, Z_NULL, 0);
const uint32_t crc32_sum = crc32(crc, (Bytef*)in_data.data(), in_data.size());
const uint32_t dataSize = in_data.size();
//Compress with GZip
std::string ret = GZipCompress(in_data);
//Remove first 2 and last 4 chars of string
ret = ret.substr(2, ret.size() - 4 - 2);
//Add header, checksum and size
char header[10] = {'\x1f', '\x8b', '\x08', '\x00', '\x00', '\x00', '\x00', '\x00', '\x00', '\x0b'};
ret = std::string(header, sizeof(header)) +
ret +
std::string((const char*)&crc32_sum, sizeof(crc32_sum)) + //Use raw binary data
std::string((const char*)&dataSize, sizeof(dataSize)); //Use raw binary data
//Encrypt with Base64
ret = base64::Encode(ret);
//replace + with - and / with _
for (auto& i : ret) {
if (i == '+')
i = '-';
if (i == '/')
i = '_';
}
//Xor with value 11 if nescessary
if(xor11)
Xor_Str(ret, 11);
//Return
return ret;
}