From 90c9fcea547c3ec15cec60e8634ec3a6dda736b7 Mon Sep 17 00:00:00 2001
From: Alexander Mankuta <alex@pointless.one>
Date: Fri, 6 Mar 2026 12:16:40 +0200
Subject: [PATCH] Fix multibyte-encoded string in streams

---
 CHANGELOG.md                 | 5 +++++
 lib/pdf/core/stream.rb       | 6 +++---
 spec/pdf/core/stream_spec.rb | 6 ++++++
 3 files changed, 14 insertions(+), 3 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 91e8b53..2389205 100644
--- a/CHANGELOG.md
+++ b/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
diff --git a/lib/pdf/core/stream.rb b/lib/pdf/core/stream.rb
index 4985480..83466a9 100644
--- a/lib/pdf/core/stream.rb
+++ b/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
diff --git a/spec/pdf/core/stream_spec.rb b/spec/pdf/core/stream_spec.rb
index 7b17d04..2bc045b 100644
--- a/spec/pdf/core/stream_spec.rb
+++ b/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