Initial commit

GDGameSave.hpp

@@ -0,0 +1,155 @@
+#pragma once
+
+#include <fstream>
+#include <zlib.h>
+#include "Base64.hpp"
+
+constexpr int CHUNK = 16384;
+constexpr int WINDOW_BITS = 15; 
+
+//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
+void StrToFile(const std::string& filename, const std::string& data) {
+	std::ofstream ofile;
+	ofile.open(filename);
+	ofile << data;
+	ofile.close();
+}
+
+//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;
+}
+
+std::string Decrypt(const std::string& filename) {
+	//load file
+	std::string ret = FileToStr(filename);
+	//Xor with value 11
+	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;
+}
+
+std::string Encrypt(const std::string& filename) {
+	//load file
+	std::string data = FileToStr(filename);
+	//Calculate crc32 checksum
+	uLong crc = crc32(0L, Z_NULL, 0);
+	uint32_t crc32_sum = crc32(crc, (Bytef*)data.data(), data.size());
+	uint32_t dataSize = data.size();
+	//Compress with GZip
+	std::string ret = GZipCompress(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
+	Xor_Str(ret, 11);
+	//Return
+	return ret;
+}