feat(terrain): file.binary.terrain.checksum setting for the check of binary terrain files against their text: full (length and checksum), simple (length, the default), off

scene/sceneterrain.cpp

@@ -614,7 +614,7 @@ bool terrain_file::convert(std::string const &Textfile, std::string const &Binar
 	return result;
 }
 
-// makes sure binary version of specified text terrain file is in place and matches the text
+// makes sure binary version of specified text terrain file is in place and matches the text, as far as the settings ask for it
 terrain_file::state terrain_file::prepare(std::string const &Textfile, std::string const &Binaryfile)
 {
 	file_header header;
@@ -628,10 +628,20 @@ terrain_file::state terrain_file::prepare(std::string const &Textfile, std::stri
 		return (binarypresent ? state::binary : state::missing);
 	}
 
+	// how far the check goes is up to the settings (file.binary.terrain.checksum): none at all, length of the text, or its length and checksum
+	if (binarypresent && Global.file_binary_terrain_checksum <= 0)
+	{
+		return state::binary;
+	}
 	std::string text;
 	auto textloaded{false};
 	if (binarypresent && (header.sourcesize == textsize))
 	{
+		if (Global.file_binary_terrain_checksum == 1)
+		{
+			// NOTE: this takes a text changed without a change of its length for the one the binary file was made from
+			return state::binary;
+		}
 		// the length is the same; the checksum tells whether the content is, too
 		textloaded = read_file(Textfile, text);
 		if (textloaded && (text.size() == header.sourcesize) && (checksum(text.data(), text.size()) == header.sourcechecksum))

scene/sceneterrain.h

@@ -39,7 +39,7 @@ class terrain_file
 	// converts specified text terrain file to binary format. returns: true on success, false otherwise.
 	// description of the result or of the failure is stored in Message, if provided
 	static bool convert(std::string const &Textfile, std::string const &Binaryfile, std::string *Message = nullptr);
-	// makes sure binary version of specified text terrain file is in place and matches the text
+	// makes sure binary version of specified text terrain file is in place and matches the text, as far as the settings ask for it
 	static state prepare(std::string const &Textfile, std::string const &Binaryfile);
 	// makes content of specified binary terrain file a part of provided region. the geometry is loaded right away,
 	// or left for the sections of the region to load when they're about to be used. returns: true on success, false otherwise

utilities/Globals.cpp

@@ -630,6 +630,15 @@ bool global_settings::ConfigParseSimulation(cParser& Parser, const std::string&
         return true;
     }
 
+    if (token == "file.binary.terrain.checksum")
+    {
+        // off, simple or full; anything else leaves the setting as it was
+        std::string mode;
+        ParseOne(Parser, mode, 1, true);
+        file_binary_terrain_checksum = (mode == "off" ? 0 : mode == "simple" ? 1 : mode == "full" ? 2 : file_binary_terrain_checksum);
+        return true;
+    }
+
     if (token == "inactivepause")
     {
         ParseOne(Parser, bInactivePause);
@@ -1582,6 +1591,7 @@ global_settings::export_as_text( std::ostream &Output ) const {
     export_as_text( Output, "latitude", fLatitudeDeg );
     export_as_text( Output, "convertmodels", iConvertModels );
     export_as_text( Output, "file.binary.terrain", file_binary_terrain );
+    export_as_text( Output, "file.binary.terrain.checksum", std::string( file_binary_terrain_checksum == 0 ? "off" : file_binary_terrain_checksum == 1 ? "simple" : "full" ) );
     export_as_text( Output, "inactivepause", bInactivePause );
     export_as_text( Output, "slowmotion", iSlowMotionMask );
     export_as_text( Output, "hideconsole", bHideConsole );

utilities/Globals.h

@@ -88,6 +88,7 @@ struct global_settings {
     int iConvertModels{ 0 }; // tworzenie plików binarnych
     int iConvertIndexRange{ 1000 }; // range of duplicate vertex scan
     bool file_binary_terrain{ true }; // enable binary terrain (de)serialization
+    int file_binary_terrain_checksum{ 1 }; // check of a binary terrain file (.btf) against its text: 0 = none, 1 = length of the text, 2 = length and checksum
 	bool file_binary_terrain_state{true};
 	int file_binary_terrain_skipped{0}; // number of terrain includes left out by the parser during the current scenery load
     // logs