ENH : add UniGB-UTF16 encodings

closes py-pdf#2812

pypdf/_cmap.py

@@ -126,6 +126,8 @@ def build_char_map_from_dict(
  "/ETenms-B5-V": "cp950",
  "/UniCNS-UTF16-H": "utf-16-be",
  "/UniCNS-UTF16-V": "utf-16-be",
+ "/UniGB-UTF16-H": "gb18030",
+ "/UniGB-UTF16-V": "gb18030",
  # UCS2 in code
 }
 

tests/test_cmap.py

@@ -214,7 +214,6 @@ def test_eten_b5():
  reader.pages[0].extract_text().startswith("1/7 \n富邦新終身壽險")
 
 
-@pytest.mark.enable_socket()
 def test_missing_entries_in_cmap():
  """
  Issue #2702: this issue is observed on damaged pdfs
@@ -231,10 +230,21 @@ def test_missing_entries_in_cmap():
 
 
 def test_null_missing_width():
- """For coverage of 2792"""
+ """For coverage of #2792"""
  writer = PdfWriter(RESOURCE_ROOT / "crazyones.pdf")
  page = writer.pages[0]
  ft = page["/Resources"]["/Font"]["/F1"]
  ft[NameObject("/Widths")] = ArrayObject()
  ft["/FontDescriptor"][NameObject("/MissingWidth")] = NullObject()
  page.extract_text()
+
+
+@pytest.mark.enable_socket()
+def test_unigb_utf16():
+ """Cf #2812"""
+ url = (
+ "https://github.com/user-attachments/files/16767536/W020240105322424121296.pdf"
+ )
+ name = "iss2812.pdf"
+ reader = PdfReader(BytesIO(get_data_from_url(url, name=name)))
+ assert "《中国能源展望 2060（2024 年版）》编写委员会" in reader.pages[1].extract_text()