Add support for reading gzip savegames, writing them isn't supported yet.

src/game.cpp

@@ -2028,7 +2028,7 @@ static int play_game(int argc, char** argv)
 			}
 
 			const std::string input_file(argv[arg + 1]);
-			if(input_file.substr(input_file.length() - 3) != ".gz") {
+			if(! is_gzip_file(input_file)) {
 
 				std::cerr << "file '" << input_file << "'isn't a .gz file\n";
 				return 2;

src/gamestatus.cpp

@@ -736,7 +736,11 @@ void read_save_file(const std::string& name, config& cfg, std::string* error_log
 
 	cfg.clear();
 	try{
-	detect_format_and_read(cfg, *file_stream, error_log);
+		if(is_gzip_file(name)) {
+			read_gz(cfg, *file_stream, error_log);
+		} else {
+			detect_format_and_read(cfg, *file_stream, error_log);
+		}
 	} catch (config::error &err)
 	{
 		std::cerr << err.message;

src/serialization/binary_or_text.cpp

@@ -83,3 +83,9 @@ bool config_writer::good() const
 	return out_.good();
 }
 
+bool is_gzip_file(const std::string& filename)
+{ 
+	return (filename.length() > 3 
+		&& filename.substr(filename.length() - 3) == ".gz"); 
+}
+

src/serialization/binary_or_text.hpp

@@ -52,4 +52,8 @@ private:
 	unsigned int level_;
 	std::string textdomain_;
 };
+
+bool is_gzip_file(const std::string& filename);
+
+
 #endif

src/serialization/parser.cpp

@@ -36,6 +36,10 @@
 #include <sstream>
 #include <stack>
 
+#include <boost/iostreams/copy.hpp>
+#include <boost/iostreams/filtering_stream.hpp>
+#include <boost/iostreams/filter/gzip.hpp>
+
 #define ERR_CF LOG_STREAM(err, config)
 #define WRN_CF LOG_STREAM(warn, config)
 #define LOG_CF LOG_STREAM(info, config)
@@ -347,6 +351,16 @@ void read(config &cfg, std::string &in, std::string* error_log)
 	parser(cfg, in)(error_log);
 }
 
+void read_gz(config &cfg, std::istream &file, std::string* error_log)
+{
+
+	boost::iostreams::filtering_stream<boost::iostreams::input> filter;
+	filter.push(boost::iostreams::gzip_decompressor());
+	filter.push(file);
+
+	parser(cfg, filter)(error_log);
+}
+
 static char const *AttributeEquals = "=";
 
 static char const *TranslatableAttributePrefix = "_ \"";

src/serialization/parser.hpp

@@ -30,6 +30,7 @@ class t_string;
 // Read data in, clobbering existing data.
 void read(config &cfg, std::istream &in, std::string* error_log = NULL); 	// Throws config::error
 void read(config &cfg, std::string &in, std::string* error_log = NULL); 	// Throws config::error
+void read_gz(config &cfg, std::istream &in, std::string* error_log=NULL);
 
 void write(std::ostream &out, config const &cfg, unsigned int level=0);
 void write_key_val(std::ostream &out, const std::string &key, const t_string &value, unsigned int level, std::string &textdomain);