First workin snap item parser

Thanks a lot to @Learath2 for explaining in irc
And for the awesome libtw2 docs by @heinrich5991

48a2573af6/doc/snapshot.md

lib/game_client.rb

@@ -300,24 +300,24 @@ class GameClient
     end
 
     item_delta = u.get_int
-    item_bits = item_delta.to_s(2).rjust(32, '0')
-    item_id_bits = item_bits[0...16]
-    item_type_bits = item_bits[16..]
-    item_id = item_id_bits.to_i(2)
-    item_type = item_type_bits.to_i(2)
+    while item_delta
+      # item_bits = item_delta.to_s(2).rjust(32, '0')
+      item_type = item_delta
+      # item_id_bits = item_bits[0...16]
+      # item_type_bits = item_bits[16..]
+      # item_id = item_id_bits.to_i(2)
+      # item_type = item_type_bits.to_i(2)
       item_meta = @snap_items[item_type]
       item_name = item_meta[:name]
       #   { name: 'obj_game_data', size: 3, fields: [
       #     { type: 'int', name: 'start_tick' },
 
       p = u.parsed.last
-    notes.push([:green, p[:pos], p[:len],
-                "\n  id   = #{item_id_bits} -> #{item_id}" \
-                "\n  type = #{item_type_bits} -> #{item_type} #{item_name}"])
+      notes.push([:green, p[:pos], p[:len], "type = #{item_type} #{item_name}"])
 
-    who = u.get_int
+      item_id = u.get_int
       p = u.parsed.last
-    notes.push([:cyan, p[:pos], p[:len], "who are you mr #{who} ?"])
+      notes.push([:cyan, p[:pos], p[:len], "id=#{item_id}"])
 
       size = item_meta[:size]
       (0...size).each do |i|
@@ -329,6 +329,8 @@ class GameClient
         desc = fields[i][:name] unless fields.nil? || fields[i].nil?
         notes.push([color, p[:pos], p[:len], "data[#{i}]=#{val} #{desc}"])
       end
+      item_delta = u.get_int
+    end
 
     # skip = 0
     # ((3 * 4)...data.size).each do |i|

lib/packer.rb

@@ -135,6 +135,7 @@ class Unpacker
 
   def get_int
     return nil if @data.nil?
+    return nil if @data.empty?
 
     # TODO: make this more performant
     #       it should not read in ALL bytes

spec/05_unpacker_spec.rb

@@ -49,6 +49,13 @@ describe 'Unpacker', :unpacker do
       expect(u.get_int).to eq(2)
     end
 
+    it 'Should return nil if no more int is found' do
+      u = Unpacker.new([0x01, 0x02])
+      expect(u.get_int).to eq(1)
+      expect(u.get_int).to eq(2)
+      expect(u.get_int).to eq(nil)
+    end
+
     it 'Should unpack negative integers' do
       u = Unpacker.new([0x40, 0x41, 0x42])
       # 0x40 => 1000 0000