From 42397536e79fdf68fb194de86bbeb3f1ed098eed Mon Sep 17 00:00:00 2001
From: cflip <cflip@cflip.net>
Date: Thu, 24 Mar 2022 12:01:09 -0600
Subject: Add a header to the level file format

---
 src/level.cpp | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/level.cpp b/src/level.cpp
index f3235a8..d5893e6 100644
--- a/src/level.cpp
+++ b/src/level.cpp
@@ -103,6 +103,8 @@ void Level::toggleTile(int x, int y)
 }
 
 static const char* DEFAULT_FILENAME = "level.non";
+static const char* LEVEL_HEADER = "NON";
+static const int LEVEL_HEADER_SIZE = 3;
 
 void Level::save() const
 {
@@ -118,6 +120,8 @@ void Level::save() const
 		return;
 	}
 
+	outputStream.write(LEVEL_HEADER, LEVEL_HEADER_SIZE);
+
 	outputStream.write((char*)&m_width, 1);
 	outputStream.write((char*)&m_height, 1);
 	outputStream.write((char*)m_tiles, m_width * m_height);
@@ -134,6 +138,14 @@ void Level::load()
 		return;
 	}
 
+	char header[LEVEL_HEADER_SIZE];
+	inputStream.read(header, LEVEL_HEADER_SIZE);
+
+	if (strncmp(header, LEVEL_HEADER, LEVEL_HEADER_SIZE) != 0) {
+		std::cerr << "Level loaded from " << DEFAULT_FILENAME << " does not match expected header!\n";
+		return;
+	}
+
 	uint8_t width, height;
 	inputStream.read((char*)&width, 1);
 	inputStream.read((char*)&height, 1);
-- 
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