Fix multibyte-encoded string in streams

CHANGELOG.md

@@ -4,6 +4,11 @@ All notable changes to this project will be documented in this file.
 
 ## Unreleased
 
+### Fixed
+
+- Correctly handle multibyte-encoded string in streams
+  Alexander Mankuta
+
 ## [0.10.0][] - 2024-03-05
 
 ### Changed

lib/pdf/core/stream.rb

@@ -23,10 +23,10 @@ def initialize(io = nil)
 
       # Append data to stream.
       #
-      # @param io [String]
+      # @param data [String]
       # @return [self]
-      def <<(io)
-        (@stream ||= +'') << io
+      def <<(data)
+        (@stream ||= ''.b) << data.dup.force_encoding(Encoding::BINARY)
         @filtered_stream = nil
         self
       end

spec/pdf/core/stream_spec.rb

@@ -50,4 +50,10 @@
 
     expect(stream.data[:DecodeParms]).to eq [{ Predictor: 15 }]
   end
+
+  it 'handles multibyte encoded strings correctly' do
+    stream << '♥'
+
+    expect(stream.data[:Length]).to eq 3
+  end
 end