GLK: FROTZ: Fix #10869 Crash initializing undo data

2 files changed, 47 insertions, 39 deletions

diff --git a/engines/glk/frotz/mem.cpp b/engines/glk/frotz/mem.cpp
index 227b67358d..ea3ca183c7 100644
--- a/engines/glk/frotz/mem.cpp
+++ b/engines/glk/frotz/mem.cpp
@@ -36,8 +36,44 @@ Mem::Mem() : story_fp(nullptr), story_size(0), first_undo(nullptr), last_undo(nu
 void Mem::initialize() {
 	initializeStoryFile();
 	loadGameHeader();
+	loadMemory();
 	initializeUndo();
 
+	// Read header extension table
+	hx_table_size = get_header_extension(HX_TABLE_SIZE);
+	hx_unicode_table = get_header_extension(HX_UNICODE_TABLE);
+	hx_flags = get_header_extension(HX_FLAGS);
+}
+
+void Mem::initializeStoryFile() {
+	if (story_fp->size() < 64)
+		error("This file is too small to be a Z-code file.");
+}
+
+void Mem::loadGameHeader() {
+	// Load header
+	zmp = (byte *)malloc(64);
+	story_fp->seek(0);
+	story_fp->read(zmp, 64);
+
+	Common::MemoryReadStream h(zmp, 64);
+	loadHeader(h);
+
+	// Calculate story file size in bytes
+	if (h_file_size != 0) {
+		story_size = (long)2 * h_file_size;
+
+		if (h_version >= V4)
+			story_size *= 2;
+		if (h_version >= V6)
+			story_size *= 2;
+	} else {
+		// Some old games lack the file size entry
+		story_size = story_fp->size();
+	}
+}
+
+void Mem::loadMemory() {
 	// Allocate memory for story data
 	if ((zmp = (zbyte *)realloc(zmp, story_size)) == nullptr)
 		error("Out of memory");
@@ -51,16 +87,6 @@ void Mem::initialize() {
 		if (story_fp->read(zmp + size, n) != n)
 			error("Story file read error");
 	}
-
-	// Read header extension table
-	hx_table_size = get_header_extension(HX_TABLE_SIZE);
-	hx_unicode_table = get_header_extension(HX_UNICODE_TABLE);
-	hx_flags = get_header_extension(HX_FLAGS);
-}
-
-void Mem::initializeStoryFile() {
-	if (story_fp->size() < 64)
-		error("This file is too small to be a Z-code file.");
 }
 
 void Mem::initializeUndo() {
@@ -82,31 +108,8 @@ void Mem::initializeUndo() {
 		_undo_slots = 0;
 	}
 
-	if (reserve_mem != 0)
-		delete reserved;
-}
-
-void Mem::loadGameHeader() {
-	// Load header
-	zmp = (byte *)malloc(64);
-	story_fp->seek(0);
-	story_fp->read(zmp, 64);
-
-	Common::MemoryReadStream h(zmp, 64);
-	loadHeader(h);
-
-	// Calculate story file size in bytes
-	if (h_file_size != 0) {
-		story_size = (long)2 * h_file_size;
-
-		if (h_version >= V4)
-			story_size *= 2;
-		if (h_version >= V6)
-			story_size *= 2;
-	} else {
-		// Some old games lack the file size entry
-		story_size = story_fp->size();
-	}
+	if (reserve_mem)
+		delete[] reserved;
 }
 
 zword Mem::get_header_extension(int entry) {
diff --git a/engines/glk/frotz/mem.h b/engines/glk/frotz/mem.h
index a632bc6e63..c58ef658e4 100644
--- a/engines/glk/frotz/mem.h
+++ b/engines/glk/frotz/mem.h
@@ -72,14 +72,19 @@ private:
 	void initializeStoryFile();
 
 	/**
-	 * Setup undo data
+	 * Handles loading the game header
 	 */
-	void initializeUndo();
+	void loadGameHeader();
 
 	/**
-	 * Handles loading the game header
+	 * Initializes memory and loads the story data
 	 */
-	void loadGameHeader();
+	void loadMemory();
+
+	/**
+	 * Setup undo data
+	 */
+	void initializeUndo();
 protected:
 	/**
 	 * Read a value from the header extension (former mouse table).