Fix #6898: Replace atoi() with strtoul()

Normalize type and parsing of generation_seed across all files
Add assert_compile() to ensure correct type

3 files changed, 7 insertions, 5 deletions

diff --git a/src/genworld.h b/src/genworld.h
index ea3faa15f..1b1c806e0 100644
--- a/src/genworld.h
+++ b/src/genworld.h
@@ -22,7 +22,7 @@ enum LandscapeGenerator {
 	LG_TERRAGENESIS = 1,  ///< TerraGenesis Perlin landscape generator
 };
 
-static const uint GENERATE_NEW_SEED = UINT_MAX; ///< Create a new random seed
+static const uint32 GENERATE_NEW_SEED = UINT32_MAX; ///< Create a new random seed
 
 /** Modes for GenerateWorld */
 enum GenWorldMode {
@@ -97,7 +97,7 @@ void SetGeneratingWorldProgress(GenWorldProgress cls, uint total);
 void IncreaseGeneratingWorldProgress(GenWorldProgress cls);
 void PrepareGenerateWorldProgress();
 void ShowGenerateWorldProgress();
-void StartNewGameWithoutGUI(uint seed);
+void StartNewGameWithoutGUI(uint32 seed);
 void ShowCreateScenario();
 void StartScenarioEditor();
 
diff --git a/src/genworld_gui.cpp b/src/genworld_gui.cpp
index 04eea8e66..b22ba5287 100644
--- a/src/genworld_gui.cpp
+++ b/src/genworld_gui.cpp
@@ -870,7 +870,7 @@ void StartScenarioEditor()
  * Start a normal game without the GUI.
  * @param seed The seed of the new game.
  */
-void StartNewGameWithoutGUI(uint seed)
+void StartNewGameWithoutGUI(uint32 seed)
 {
 	/* GenerateWorld takes care of the possible GENERATE_NEW_SEED value in 'seed' */
 	_settings_newgame.game_creation.generation_seed = seed;
diff --git a/src/openttd.cpp b/src/openttd.cpp
index 510f00427..a849a2ebd 100644
--- a/src/openttd.cpp
+++ b/src/openttd.cpp
@@ -385,7 +385,7 @@ void OpenBrowser(const char *url)
 /** Callback structure of statements to be executed after the NewGRF scan. */
 struct AfterNewGRFScan : NewGRFScanCallback {
 	Year startyear;                    ///< The start year.
-	uint generation_seed;              ///< Seed for the new game.
+	uint32 generation_seed;            ///< Seed for the new game.
 	char *dedicated_host;              ///< Hostname for the dedicated server.
 	uint16 dedicated_port;             ///< Port for the dedicated server.
 	char *network_conn;                ///< Information about the server to connect to, or NULL.
@@ -394,6 +394,8 @@ struct AfterNewGRFScan : NewGRFScanCallback {
 	bool *save_config_ptr;             ///< The pointer to the save config setting.
 	bool save_config;                  ///< The save config setting.
 
+	assert_compile(sizeof(generation_seed) == sizeof(_settings_game.game_creation.generation_seed));
+
 	/**
 	 * Create a new callback.
 	 * @param save_config_ptr Pointer to the save_config local variable which
@@ -666,7 +668,7 @@ int openttd_main(int argc, char *argv[])
 
 			goto exit_noshutdown;
 		}
-		case 'G': scanner->generation_seed = atoi(mgo.opt); break;
+		case 'G': scanner->generation_seed = strtoul(mgo.opt, NULL, 10); break;
 		case 'c': free(_config_file); _config_file = stredup(mgo.opt); break;
 		case 'x': scanner->save_config = false; break;
 		case 'h':