Do not truncate too long strings on writing ESM

apps/openmw_test_suite/CMakeLists.txt

@@ -91,6 +91,7 @@ file(GLOB UNITTEST_SRC_FILES
 
     esm3/readerscache.cpp
     esm3/testsaveload.cpp
+    esm3/testesmwriter.cpp
 
     nifosg/testnifloader.cpp
 )

apps/openmw_test_suite/esm3/testesmwriter.cpp

@@ -0,0 +1,54 @@
+#include <components/esm3/esmwriter.hpp>
+
+#include <gmock/gmock.h>
+#include <gtest/gtest.h>
+
+#include <algorithm>
+#include <memory>
+#include <random>
+
+namespace ESM
+{
+    namespace
+    {
+        using namespace ::testing;
+
+        struct Esm3EsmWriterTest : public Test
+        {
+            std::minstd_rand mRandom;
+            std::uniform_int_distribution<short> mRefIdDistribution{ 'a', 'z' };
+
+            std::string generateRandomString(std::size_t size)
+            {
+                std::string result;
+                std::generate_n(
+                    std::back_inserter(result), size, [&] { return static_cast<char>(mRefIdDistribution(mRandom)); });
+                return result;
+            }
+        };
+
+        TEST_F(Esm3EsmWriterTest, saveShouldThrowExceptionOnWhenTruncatingHeaderStrings)
+        {
+            const std::string author = generateRandomString(33);
+            const std::string description = generateRandomString(257);
+
+            std::stringstream stream;
+
+            ESMWriter writer;
+            writer.setAuthor(author);
+            writer.setDescription(description);
+            writer.setFormatVersion(CurrentSaveGameFormatVersion);
+            EXPECT_THROW(writer.save(stream), std::runtime_error);
+        }
+
+        TEST_F(Esm3EsmWriterTest, writeFixedStringShouldThrowExceptionOnTruncate)
+        {
+            std::stringstream stream;
+
+            ESMWriter writer;
+            writer.setFormatVersion(CurrentSaveGameFormatVersion);
+            writer.save(stream);
+            EXPECT_THROW(writer.writeFixedSizeString(generateRandomString(33), 32), std::runtime_error);
+        }
+    }
+}

components/esm3/esmwriter.cpp

@@ -167,11 +167,14 @@ namespace ESM
         endRecord(name);
     }
 
-    void ESMWriter::writeFixedSizeString(const std::string& data, int size)
+    void ESMWriter::writeFixedSizeString(const std::string& data, std::size_t size)
     {
         std::string string;
         if (!data.empty())
             string = mEncoder ? mEncoder->getLegacyEnc(data) : data;
+        if (string.size() > size)
+            throw std::runtime_error("Fixed string data is too long: \"" + string + "\" ("
+                + std::to_string(string.size()) + " > " + std::to_string(size) + ")");
         string.resize(size);
         write(string.c_str(), string.size());
     }

components/esm3/esmwriter.hpp

@@ -136,7 +136,7 @@ namespace ESM
         void startSubRecord(NAME name);
         void endRecord(NAME name);
         void endRecord(uint32_t name);
-        void writeFixedSizeString(const std::string& data, int size);
+        void writeFixedSizeString(const std::string& data, std::size_t size);
         void writeHString(const std::string& data);
         void writeHCString(const std::string& data);
         void writeName(NAME data);