From 7586e8d5abf12161e51b53c0614981f374ac5bab Mon Sep 17 00:00:00 2001
From: xypwn <darwin@Arch.localdomain>
Date: Tue, 5 May 2020 13:40:52 +0200
Subject: [PATCH] Add library functionality for level data

---
 GDGameSave.hpp | 51 ++++++++++++++++++++++++++++----------------------
 Main.cpp       | 16 ++++++++++------
 2 files changed, 39 insertions(+), 28 deletions(-)

diff --git a/GDGameSave.hpp b/GDGameSave.hpp
index f5ba638..0fb060d 100644
--- a/GDGameSave.hpp
+++ b/GDGameSave.hpp
@@ -8,8 +8,7 @@ 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)
-{
+bool IsFile(const std::string& filename) {
 	std::ifstream file(filename);
 	const bool ret = file.good();
 	file.close();
@@ -44,8 +43,7 @@ void Xor_Str(std::string& str, unsigned char key) {
 	}
 }
 
-std::string GZipDecompress(const std::string& in)
-{
+std::string GZipDecompress(const std::string& in) {
 	//Initialize all members of strm to be 0
 	z_stream strm = {};
 	//Output buffer
@@ -82,8 +80,7 @@ std::string GZipDecompress(const std::string& in)
 	return final_output;
 }
 
-std::string GZipCompress(const std::string& in)
-{
+std::string GZipCompress(const std::string& in) {
 	//Initialize all members of strm to be 0
     z_stream strm = {};
 	//Output buffer
@@ -114,11 +111,17 @@ std::string GZipCompress(const std::string& in)
 	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);
+/** @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 == '-')
@@ -134,20 +137,23 @@ std::string Decrypt(const std::string& filename) {
 	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();
+/** @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(data);
+	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(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
@@ -160,8 +166,9 @@ std::string Encrypt(const std::string& filename) {
 		if (i == '/')
 			i = '_';
 	}
-	//Xor with value 11
-	Xor_Str(ret, 11);
+	//Xor with value 11 if nescessary
+	if(xor11)
+		Xor_Str(ret, 11);
 	//Return
 	return ret;
 }
\ No newline at end of file
diff --git a/Main.cpp b/Main.cpp
index 859d0b7..5e8d925 100755
--- a/Main.cpp
+++ b/Main.cpp
@@ -20,24 +20,27 @@ const std::string commands = R"(Commands:
     3: Encrypt and save to GD folder
     0: Quit)";
 
-enum class Command
-{
+enum class Command {
 	Decrypt,
 	Encrypt
 };
 
-bool ExecCommand(Command cmd, const std::string& in_filename, const std::string& out_filename)
-{
+bool ExecCommand(Command cmd, const std::string& in_filename, const std::string& out_filename) {
+	//Check if input file is valid
 	if(!IsFile(in_filename))
 	{
 		std::cerr << "ERROR: Could not open file " << in_filename << " for reading" << std::endl;
 		return false;
 	}
+	//Read file data into a string
+	std::string data = FileToStr(in_filename);
+
 	switch(cmd)
 	{
 	case Command::Decrypt:
 		std::cout << "Decrypting " << in_filename << "..." << std::endl;
-		if(!StrToFile(out_filename, Decrypt(in_filename)))
+		// Attempt to decrypt data and save it in the given output file
+		if(!StrToFile(out_filename, Decrypt(data, true)))
 		{
 			std::cerr << "ERROR: Could not open file " << out_filename << " for writing" << std::endl;
 			return false;
@@ -45,7 +48,8 @@ bool ExecCommand(Command cmd, const std::string& in_filename, const std::string&
 		break;
 	case Command::Encrypt:
 		std::cout << "Encrypting " << in_filename << "..." << std::endl;
-		if(!StrToFile(out_filename, Encrypt(in_filename)))
+		// Attempt to encrypt data and save it in the given output file
+		if(!StrToFile(out_filename, Encrypt(data, true)))
 		{
 			std::cerr << "ERROR: Could not open file " << out_filename << " for writing" << std::endl;
 			return false;