From 01d8f8d8e62074a468e9bc070917b332a16e94a9 Mon Sep 17 00:00:00 2001
From: ChillerDragon <ChillerDragon@gmail.com>
Date: Sun, 6 Nov 2022 13:57:53 +0100
Subject: [PATCH] Single byte negative int unpacks wrong

---
 lib/packer.rb            |  4 ++++
 spec/04_packer_spec.rb   | 11 +++++++++++
 spec/05_unpacker_spec.rb | 21 +++++++++++++++++++++
 3 files changed, 36 insertions(+)

diff --git a/lib/packer.rb b/lib/packer.rb
index a17b9fb..39d0953 100644
--- a/lib/packer.rb
+++ b/lib/packer.rb
@@ -130,3 +130,7 @@ class Unpacker
     bits.join.to_i(2) * sign
   end
 end
+
+u = Unpacker.new(['01000000'.to_i(2)])
+# expect -1
+p u.get_int
diff --git a/spec/04_packer_spec.rb b/spec/04_packer_spec.rb
index 21fb465..31a7b46 100644
--- a/spec/04_packer_spec.rb
+++ b/spec/04_packer_spec.rb
@@ -28,6 +28,17 @@ describe 'Packer', :packer do
       expect(Packer.pack_int(-3).first.to_s(2)).to eq('1000010')
       expect(Packer.pack_int(-4).first.to_s(2)).to eq('1000011')
     end
+
+    # https://github.com/ddnet/ddnet/pull/6015
+    it 'Should pack the same as ddnet C++ tests -3..3' do
+      expect(Packer.pack_int(1).first.to_s(2).rjust(8, '0')).to eq('00000001')
+      expect(Packer.pack_int(2).first.to_s(2).rjust(8, '0')).to eq('00000010')
+      expect(Packer.pack_int(3).first.to_s(2).rjust(8, '0')).to eq('00000011')
+
+      expect(Packer.pack_int(-1).first.to_s(2).rjust(8, '0')).to eq('01000000')
+      expect(Packer.pack_int(-2).first.to_s(2).rjust(8, '0')).to eq('01000001')
+      expect(Packer.pack_int(-3).first.to_s(2).rjust(8, '0')).to eq('01000010')
+    end
   end
 
   context 'Pack multi byte integers' do
diff --git a/spec/05_unpacker_spec.rb b/spec/05_unpacker_spec.rb
index 06e6312..ce5f3de 100644
--- a/spec/05_unpacker_spec.rb
+++ b/spec/05_unpacker_spec.rb
@@ -40,6 +40,27 @@ describe 'Unpacker', :unpacker do
       end
     end
 
+    # https://github.com/ddnet/ddnet/pull/6015
+    it 'Should unpack the same as ddnet C++ tests -3..3' do
+      expect(Packer.pack_int(1).first.to_s(2).rjust(8, '0')).to eq('00000001')
+      expect(Packer.pack_int(2).first.to_s(2).rjust(8, '0')).to eq('00000010')
+      expect(Packer.pack_int(3).first.to_s(2).rjust(8, '0')).to eq('00000011')
+
+      expect(Packer.pack_int(-1).first.to_s(2).rjust(8, '0')).to eq('01000000')
+      expect(Packer.pack_int(-2).first.to_s(2).rjust(8, '0')).to eq('01000001')
+      expect(Packer.pack_int(-3).first.to_s(2).rjust(8, '0')).to eq('01000010')
+
+      u = Unpacker.new(['00000001'.to_i(2)])
+      expect(u.get_int).to eq(1)
+      u = Unpacker.new(['00000010'.to_i(2)])
+      expect(u.get_int).to eq(2)
+      u = Unpacker.new(['00000011'.to_i(2)])
+      expect(u.get_int).to eq(3)
+
+      # u = Unpacker.new(['01000000'.to_i(2)])
+      # expect(u.get_int).to eq(-1)
+    end
+
     # it 'Should pack and unpack and match from -3 to 3' do
     #   (-3..3).each do |i|
     #     u = Unpacker.new(Packer.pack_int(i))