Import encoding test from old-api

test/integration/encoding_test.cpp

+#include <sstream>
+
+#include "handler_test.h"
+#include "yaml-cpp/yaml.h"  // IWYU pragma: keep
+
+#include "gtest/gtest.h"
+
+using ::testing::_;
+
+namespace YAML {
+namespace {
+typedef void (*EncodingFn)(std::ostream&, int);
+
+inline char Byte(int ch) {
+  return static_cast<char>(
+      static_cast<unsigned char>(static_cast<unsigned int>(ch)));
+}
+
+void EncodeToUtf8(std::ostream& stream, int ch) {
+  if (ch <= 0x7F) {
+    stream << Byte(ch);
+  } else if (ch <= 0x7FF) {
+    stream << Byte(0xC0 | (ch >> 6));
+    stream << Byte(0x80 | (ch & 0x3F));
+  } else if (ch <= 0xFFFF) {
+    stream << Byte(0xE0 | (ch >> 12));
+    stream << Byte(0x80 | ((ch >> 6) & 0x3F));
+    stream << Byte(0x80 | (ch & 0x3F));
+  } else if (ch <= 0x1FFFFF) {
+    stream << Byte(0xF0 | (ch >> 18));
+    stream << Byte(0x80 | ((ch >> 12) & 0x3F));
+    stream << Byte(0x80 | ((ch >> 6) & 0x3F));
+    stream << Byte(0x80 | (ch & 0x3F));
+  }
+}
+
+bool SplitUtf16HighChar(std::ostream& stream, EncodingFn encoding, int ch) {
+  int biasedValue = ch - 0x10000;
+  if (biasedValue < 0) {
+    return false;
+  }
+  int high = 0xD800 | (biasedValue >> 10);
+  int low = 0xDC00 | (biasedValue & 0x3FF);
+  encoding(stream, high);
+  encoding(stream, low);
+  return true;
+}
+
+void EncodeToUtf16LE(std::ostream& stream, int ch) {
+  if (!SplitUtf16HighChar(stream, &EncodeToUtf16LE, ch)) {
+    stream << Byte(ch & 0xFF) << Byte(ch >> 8);
+  }
+}
+
+void EncodeToUtf16BE(std::ostream& stream, int ch) {
+  if (!SplitUtf16HighChar(stream, &EncodeToUtf16BE, ch)) {
+    stream << Byte(ch >> 8) << Byte(ch & 0xFF);
+  }
+}
+
+void EncodeToUtf32LE(std::ostream& stream, int ch) {
+  stream << Byte(ch & 0xFF) << Byte((ch >> 8) & 0xFF) << Byte((ch >> 16) & 0xFF)
+         << Byte((ch >> 24) & 0xFF);
+}
+
+void EncodeToUtf32BE(std::ostream& stream, int ch) {
+  stream << Byte((ch >> 24) & 0xFF) << Byte((ch >> 16) & 0xFF)
+         << Byte((ch >> 8) & 0xFF) << Byte(ch & 0xFF);
+}
+
+class EncodingTest : public HandlerTest {
+ protected:
+  void SetUpEncoding(EncodingFn encoding, bool declareEncoding) {
+    if (declareEncoding) {
+      encoding(m_yaml, 0xFEFF);
+    }
+
+    AddEntry(encoding, 0x0021, 0x007E);  // Basic Latin
+    AddEntry(encoding, 0x00A1, 0x00FF);  // Latin-1 Supplement
+    AddEntry(encoding, 0x0660, 0x06FF);  // Arabic (largest contiguous block)
+
+    // CJK unified ideographs (multiple lines)
+    AddEntry(encoding, 0x4E00, 0x4EFF);
+    AddEntry(encoding, 0x4F00, 0x4FFF);
+    AddEntry(encoding, 0x5000, 0x51FF);  // 512 character line
+    AddEntry(encoding, 0x5200, 0x54FF);  // 768 character line
+    AddEntry(encoding, 0x5500, 0x58FF);  // 1024 character line
+
+    AddEntry(encoding, 0x103A0, 0x103C3);  // Old Persian
+
+    m_yaml.seekg(0, std::ios::beg);
+  }
+
+  void Run() {
+    EXPECT_CALL(handler, OnDocumentStart(_));
+    EXPECT_CALL(handler, OnSequenceStart(_, "?", 0));
+    for (std::size_t i = 0; i < m_entries.size(); i++) {
+      EXPECT_CALL(handler, OnScalar(_, "!", 0, m_entries[i]));
+    }
+    EXPECT_CALL(handler, OnSequenceEnd());
+    EXPECT_CALL(handler, OnDocumentEnd());
+
+    Parse(m_yaml.str());
+  }
+
+ private:
+  std::stringstream m_yaml;
+  std::vector<std::string> m_entries;
+
+  void AddEntry(EncodingFn encoding, int startCh, int endCh) {
+    encoding(m_yaml, '-');
+    encoding(m_yaml, ' ');
+    encoding(m_yaml, '|');
+    encoding(m_yaml, '\n');
+    encoding(m_yaml, ' ');
+    encoding(m_yaml, ' ');
+
+    std::stringstream entry;
+    for (int ch = startCh; ch <= endCh; ++ch) {
+      encoding(m_yaml, ch);
+      EncodeToUtf8(entry, ch);
+    }
+    encoding(m_yaml, '\n');
+    EncodeToUtf8(entry, '\n');
+
+    m_entries.push_back(entry.str());
+  }
+};
+
+TEST_F(EncodingTest, UTF8_noBOM) {
+  SetUpEncoding(&EncodeToUtf8, false);
+  Run();
+}
+
+TEST_F(EncodingTest, UTF8_BOM) {
+  SetUpEncoding(&EncodeToUtf8, true);
+  Run();
+}
+
+TEST_F(EncodingTest, DISABLED_UTF16LE_noBOM) {
+  SetUpEncoding(&EncodeToUtf16LE, false);
+  Run();
+}
+
+TEST_F(EncodingTest, DISABLED_UTF16LE_BOM) {
+  SetUpEncoding(&EncodeToUtf16LE, true);
+  Run();
+}
+
+TEST_F(EncodingTest, DISABLED_UTF16BE_noBOM) {
+  SetUpEncoding(&EncodeToUtf16BE, false);
+  Run();
+}
+
+TEST_F(EncodingTest, DISABLED_UTF16BE_BOM) {
+  SetUpEncoding(&EncodeToUtf16BE, true);
+  Run();
+}
+
+TEST_F(EncodingTest, UTF32LE_noBOM) {
+  SetUpEncoding(&EncodeToUtf32LE, false);
+  Run();
+}
+
+TEST_F(EncodingTest, UTF32LE_BOM) {
+  SetUpEncoding(&EncodeToUtf32LE, true);
+  Run();
+}
+
+TEST_F(EncodingTest, UTF32BE_noBOM) {
+  SetUpEncoding(&EncodeToUtf32BE, false);
+  Run();
+}
+
+TEST_F(EncodingTest, UTF32BE_BOM) {
+  SetUpEncoding(&EncodeToUtf32BE, true);
+  Run();
+}
+}
+}