From 0f318e509e4051506100ae5825773d96b1457b80 Mon Sep 17 00:00:00 2001
From: KikooDX <kikoodx@paranoici.org>
Date: Wed, 24 Feb 2021 17:58:38 +0100
Subject: [PATCH] Add versioning byte. Remove bloat goal from README.md

I don't want to ever use this, but if someone want to add weird stuff
to this format I think it's for the best to do this.
---
 README.md     |   5 ++---
 kbleformat.md |   9 +++++----
 sample.kble   | Bin 517 -> 518 bytes
 src/level.zig |  19 +++++++++++++------
 4 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/README.md b/README.md
index 78dfd8d..3c68ed2 100644
--- a/README.md
+++ b/README.md
@@ -7,10 +7,9 @@ This is a work in progress program in unusable state.
 Subject to change.
 * Efficiency, simplicity and clarity are key goals.
 * Fully keyboard driven modal editing. Mouse support is secondary.
-* GUI application made in [Zig](https://ziglang.org/) with
+* GUI software made in [Zig](https://ziglang.org/) with
   [raylib](https://www.raylib.com/).
 * Configurable (format unknown).
-* [LDtk](https://ldtk.io/) inspired tiling rulesets.
 
 # Build instructions
 Build requirements: [Zig](https://ziglang.org/download/) master branch,
@@ -44,7 +43,7 @@ Verbs:
 
 File (read/write):
 * `e`: load level contained in `sample.kble`
-* `w`: write level to `sample.kble`
+* `w`: write level to `sample.kble`  
 *See `kbleformat.md` for technical informations.*
 
 Modes:
diff --git a/kbleformat.md b/kbleformat.md
index f97442f..88caa21 100644
--- a/kbleformat.md
+++ b/kbleformat.md
@@ -4,9 +4,10 @@ Recommanded extension: `.kble`
 Data stored: level size, level content.
 
 Encoding:
-* first byte indicates how big is a chunk of data (in bytes)
-* second and third bytes indicates level width
-* fourth and fifth bytes indicates level height
-* 6th => (6 + data_size * width * height) contains level data
+* 1st byte indicates format version (`0` currently)
+* 2nd byte indicates how big is a chunk of data (in bytes)
+* 3rd and 4th bytes indicates level width
+* 5th and 6th bytes indicates level height
+* 7th → (7 + data_size × width × height) contains level data
 
 If the encoding is incorrect, return an error or crash the program.
diff --git a/sample.kble b/sample.kble
index 3e6f813bafcbf268b323039abcb1c73c61cd54b5..9096459aa2422242b21b5719466406e1f02bbd9e 100644
GIT binary patch
delta 9
QcmZo=X=7nz*ucsJ01CMQ%m4rY

delta 21
ccmZo;X=Pz$Vh~^um@LSsJJFwOqwPsX04p2>uK)l5

diff --git a/src/level.zig b/src/level.zig
index db4a92d..013d0fd 100644
--- a/src/level.zig
+++ b/src/level.zig
@@ -9,7 +9,6 @@ const ray = @cImport({
 });
 const std = @import("std");
 const expect = std.testing.expect;
-const assert = std.debug.assert;
 
 const Vec2 = @import("vec2.zig");
 const Rect = @import("rect.zig");
@@ -72,10 +71,16 @@ pub fn init_read(allocator: *std.mem.Allocator, kble_file_path: []const u8) !Sel
     // Get reader.
     var reader: std.fs.File.Reader = file.reader();
 
-    // Read first byte and check than the value matches the size of cell_type.
+    // Read first byte and check than the value matches the current format version.
+    {
+        const version = try reader.readByte();
+        if (version != 0) unreachable;
+    }
+
+    // Read second byte and check than the value matches the size of cell_type.
     {
         const cell_spec_byte = try reader.readByte();
-        assert(cell_spec_byte == expected_bytes_per_cell);
+        if (cell_spec_byte != expected_bytes_per_cell) unreachable;
     }
 
     // Read four bytes and use them for width and height. Two bytes each.
@@ -99,8 +104,8 @@ pub fn init_read(allocator: *std.mem.Allocator, kble_file_path: []const u8) !Sel
         });
 
         // Non-null width and height.
-        assert(width > 0);
-        assert(height > 0);
+        if (width == 0) unreachable;
+        if (height == 0) unreachable;
 
         self = try Self.init(allocator, width, height);
     }
@@ -130,7 +135,9 @@ pub fn write(self: Self, kble_file_path: []const u8) !void {
     // Get writer.
     var writer: std.fs.File.Writer = file.writer();
 
-    // Write first byte, indicates cell size in bytes.
+    // Write first byte, kbleformat version number (hopefully will never have to increase).
+    try writer.writeByte(0);
+    // Write second byte, indicates cell size in bytes.
     try writer.writeByte(expected_bytes_per_cell);
 
     // Write level height and level width.