Use ZStandard for Park and Replay Files (#24734)

.github/workflows/ci.yml

@@ -489,7 +489,7 @@ jobs:
     name: Ubuntu Linux (AppImage, x86_64)
     runs-on: ubuntu-latest
     needs: [check-code-formatting, build_variables]
-    container: openrct2/openrct2-build:14-jammy
+    container: openrct2/openrct2-build:21-jammy
     steps:
       - name: Checkout
         uses: actions/checkout@v4

.github/workflows/clang-tidy.yml

@@ -12,7 +12,7 @@ on:
 jobs:
   clang-tidy-check:
     runs-on: ubuntu-latest
-    container: openrct2/openrct2-build:19-noble
+    container: openrct2/openrct2-build:20-noble
     steps:
     - uses: actions/checkout@v4
     - uses: ZehMatt/clang-tidy-annotations@v1

distribution/changelog.txt

@@ -1,5 +1,6 @@
 0.4.26 (in development)
 ------------------------------------------------------------------------
+- Improved: [#24734] Save files now use Zstd compression for faster saving and smaller files.
 - Improved: [#24893] The ride list now has headers, and can be sorted in both directions.
 - Fix: [#16988] AppImage version does not show changelog.
 

distribution/readme.txt

@@ -1,4 +1,4 @@
-Last updated:    2024-11-19
+Last updated:    2025-08-04
 ------------------------------------------------------------------------
 
 
@@ -155,6 +155,7 @@ zlib             | zlib licence.
 Google Test      | BSD 3 clause licence.
 Google Benchmark | Apache 2.0 licence.
 sfl              | zlib licence.
+zstd             | BSD 3 clause license.
 
 Licences for sub-libraries used by the above may vary. For more information, visit the libraries' respective official websites.
 

openrct2.common.props

@@ -88,7 +88,7 @@
       <GenerateDebugInformation>DebugFull</GenerateDebugInformation>
       <AdditionalDependencies>brotlicommon.lib;brotlidec.lib;brotlienc.lib;%(AdditionalDependencies)</AdditionalDependencies>
       <AdditionalDependencies Condition="'$(Breakpad)'=='true' and ('$(Platform)'=='Win32' or '$(Platform)'=='x64')">libbreakpadd.lib;libbreakpad_clientd.lib;%(AdditionalDependencies)</AdditionalDependencies>
-      <AdditionalDependencies>bz2d.lib;discord-rpc.lib;flac.lib;freetyped.lib;libpng16d.lib;ogg.lib;speexdsp.lib;SDL2-staticd.lib;vorbis.lib;vorbisfile.lib;zip.lib;zlibd.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <AdditionalDependencies>bz2d.lib;discord-rpc.lib;flac.lib;freetyped.lib;libpng16d.lib;ogg.lib;speexdsp.lib;SDL2-staticd.lib;vorbis.lib;vorbisfile.lib;zip.lib;zlibd.lib;zstd.lib;%(AdditionalDependencies)</AdditionalDependencies>
     </Link>
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(Configuration)'=='Release' or '$(Configuration)'=='ReleaseLTCG'">
@@ -109,7 +109,7 @@
       <OptimizeReferences>true</OptimizeReferences>
       <AdditionalDependencies>brotlicommon.lib;brotlidec.lib;brotlienc.lib;%(AdditionalDependencies)</AdditionalDependencies>
       <AdditionalDependencies Condition="'$(Breakpad)'=='true' and ('$(Platform)'=='Win32' or '$(Platform)'=='x64')">libbreakpad.lib;libbreakpad_client.lib;%(AdditionalDependencies)</AdditionalDependencies>
-      <AdditionalDependencies>bz2.lib;discord-rpc.lib;flac.lib;freetype.lib;libpng16.lib;ogg.lib;speexdsp.lib;SDL2-static.lib;vorbis.lib;vorbisfile.lib;zip.lib;zlib.lib;%(AdditionalDependencies)</AdditionalDependencies>
+      <AdditionalDependencies>bz2.lib;discord-rpc.lib;flac.lib;freetype.lib;libpng16.lib;ogg.lib;speexdsp.lib;SDL2-static.lib;vorbis.lib;vorbisfile.lib;zip.lib;zlib.lib;zstd.lib;%(AdditionalDependencies)</AdditionalDependencies>
     </Link>
   </ItemDefinitionGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.props" />

scripts/build-emscripten

@@ -7,6 +7,7 @@ START_DIR=$(pwd)
 SPEEXDSP_ROOT=/ext/speexdsp
 ICU_ROOT=/ext/icu/icu4c/source
 LIBZIP_ROOT=/ext/libzip
+ZSTD_ROOT=/ext/zstd
 JSON_DIR=/usr/include/nlohmann/
 
 emcmake cmake ../ \
@@ -25,7 +26,8 @@ emcmake cmake ../ \
 	-DICU_DATA_LIBRARIES=$ICU_ROOT/lib/libicuuc.so \
 	-DICU_DT_LIBRARY_RELEASE="$ICU_ROOT/stubdata/libicudata.so" \
 	-DLIBZIP_LIBRARIES="$LIBZIP_ROOT/build/lib/libzip.a" \
-	-DEMSCRIPTEN_FLAGS="-s USE_SDL=2 -s USE_BZIP2=1 -s USE_LIBPNG=1 -pthread -O3" \
+	-DZSTD_LIBRARIES="$ZSTD_ROOT/build/build/lib/libzstd.a" \
+	-DEMSCRIPTEN_FLAGS="-s USE_SDL=2 -s USE_ZLIB=1 -s USE_BZIP2=1 -s USE_LIBPNG=1 -pthread -O3" \
 	-DEMSCRIPTEN_LDFLAGS="-Wno-pthreads-mem-growth -s SAFE_HEAP=0 -s ALLOW_MEMORY_GROWTH=1 -s MAXIMUM_MEMORY=4GB -s INITIAL_MEMORY=2GB -s STACK_SIZE=8388608 -s MIN_WEBGL_VERSION=2 -s MAX_WEBGL_VERSION=2 -s PTHREAD_POOL_SIZE=120 -pthread -s EXPORTED_RUNTIME_METHODS=ccall,FS,callMain,UTF8ToString,stringToNewUTF8 -lidbfs.js --use-preload-plugins -s MODULARIZE=1 -s 'EXPORT_NAME=\"OPENRCT2_WEB\"'"
 
 emmake ninja

src/openrct2-android/app/src/main/CMakeLists.txt

@@ -46,6 +46,7 @@ ExternalProject_Add(libs
         ${CMAKE_BINARY_DIR}/libs/lib/${CMAKE_SHARED_LIBRARY_PREFIX}icui18n${CMAKE_SHARED_LIBRARY_SUFFIX}
         ${CMAKE_BINARY_DIR}/libs/lib/${CMAKE_SHARED_LIBRARY_PREFIX}icuuc${CMAKE_SHARED_LIBRARY_SUFFIX}
         ${CMAKE_BINARY_DIR}/libs/lib/${CMAKE_SHARED_LIBRARY_PREFIX}z${CMAKE_SHARED_LIBRARY_SUFFIX}
+        ${CMAKE_BINARY_DIR}/libs/lib/${CMAKE_SHARED_LIBRARY_PREFIX}zstd${CMAKE_SHARED_LIBRARY_SUFFIX}
         ${CMAKE_BINARY_DIR}/libs/lib/${CMAKE_STATIC_LIBRARY_PREFIX}SDL2main${CMAKE_STATIC_LIBRARY_SUFFIX}
 
     LOG_DOWNLOAD 1
@@ -78,6 +79,7 @@ add_custom_command(TARGET libs POST_BUILD
     COMMAND ${CMAKE_COMMAND} -E copy "${CMAKE_BINARY_DIR}/libs/lib/libspeexdsp.so" ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}
     COMMAND ${CMAKE_COMMAND} -E copy "${CMAKE_BINARY_DIR}/libs/lib/libssl.so" ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}
     COMMAND ${CMAKE_COMMAND} -E copy "${CMAKE_BINARY_DIR}/libs/lib/libz.so" ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}
+    COMMAND ${CMAKE_COMMAND} -E copy "${CMAKE_BINARY_DIR}/libs/lib/libzstd.so" ${CMAKE_LIBRARY_OUTPUT_DIRECTORY}
 )
 
 add_library(freetype SHARED IMPORTED)
@@ -98,6 +100,12 @@ set_target_properties(z PROPERTIES IMPORTED_LOCATION
 )
 add_dependencies(z libs)
 
+add_library(zstd SHARED IMPORTED)
+set_target_properties(zstd PROPERTIES IMPORTED_LOCATION
+    ${CMAKE_BINARY_DIR}/libs/lib/${CMAKE_SHARED_LIBRARY_PREFIX}zstd${CMAKE_SHARED_LIBRARY_SUFFIX}
+)
+add_dependencies(zstd libs)
+
 add_library(SDL2 SHARED IMPORTED)
 set_target_properties(SDL2 PROPERTIES IMPORTED_LOCATION
     ${CMAKE_BINARY_DIR}/libs/lib/${CMAKE_SHARED_LIBRARY_PREFIX}SDL2${CMAKE_SHARED_LIBRARY_SUFFIX}
@@ -250,7 +258,7 @@ file(GLOB_RECURSE OPENRCT2_CLI_SOURCES
     "${ORCT2_ROOT}/src/openrct2-cli/*.hpp")
 
 add_library(openrct2 SHARED ${LIBOPENRCT2_SOURCES})
-target_link_libraries(openrct2 android stdc++ log dl SDL2 png z icu icuuc icudata crypto ssl freetype)
+target_link_libraries(openrct2 android stdc++ log dl SDL2 png z zstd icu icuuc icudata crypto ssl freetype)
 
 add_library(openrct2-ui SHARED ${OPENRCT2_GUI_SOURCES})
 target_link_libraries(openrct2-ui openrct2 android stdc++ GLESv1_CM GLESv2 SDL2main speexdsp brotlicommon brotlidec bz2 freetype ogg vorbis vorbisfile FLAC)

src/openrct2/CMakeLists.txt

@@ -121,12 +121,14 @@ if (EMSCRIPTEN)
 elseif (MSVC)
     find_package(png 1.6 REQUIRED)
     find_package(zlib REQUIRED)
+    find_package(zstd REQUIRED)
 
     find_path(LIBZIP_INCLUDE_DIRS zip.h)
     find_library(LIBZIP_LIBRARIES zip)
 else ()
     PKG_CHECK_MODULES(LIBZIP REQUIRED IMPORTED_TARGET libzip>=1.0)
     PKG_CHECK_MODULES(ZLIB REQUIRED IMPORTED_TARGET zlib)
+    PKG_CHECK_MODULES(ZSTD REQUIRED IMPORTED_TARGET libzstd)
 
     PKG_CHECK_MODULES(PNG IMPORTED_TARGET libpng>=1.6)
     if (NOT PNG_FOUND)
@@ -144,18 +146,21 @@ if (STATIC)
     target_link_libraries(libopenrct2
                                      ${PNG_STATIC_LIBRARIES}
                                      ${ZLIB_STATIC_LIBRARIES}
-                                     ${LIBZIP_STATIC_LIBRARIES})
+                                     ${LIBZIP_STATIC_LIBRARIES}
+                                     ${ZSTD_STATIC_LIBRARIES})
 else ()
     if (NOT MSVC AND NOT EMSCRIPTEN)
         target_link_libraries(libopenrct2
                                      PkgConfig::PNG
                                      PkgConfig::ZLIB
-                                     PkgConfig::LIBZIP)
+                                     PkgConfig::LIBZIP
+                                     PkgConfig::ZSTD)
     else ()
         target_link_libraries(libopenrct2
                                      ${PNG_LIBRARIES}
                                      ${ZLIB_LIBRARIES}
-                                     ${LIBZIP_LIBRARIES})
+                                     ${LIBZIP_LIBRARIES}
+                                     ${ZSTD_LIBRARIES})
     endif ()
 endif ()
 
@@ -235,6 +240,7 @@ endif()
 target_include_directories(libopenrct2 SYSTEM PRIVATE ${LIBZIP_INCLUDE_DIRS})
 target_include_directories(libopenrct2 SYSTEM PRIVATE ${PNG_INCLUDE_DIRS}
                                                           ${ZLIB_INCLUDE_DIRS})
+target_include_directories(libopenrct2 SYSTEM PRIVATE ${ZSTD_INCLUDE_DIRS})
 include_directories(libopenrct2 SYSTEM ${CMAKE_CURRENT_LIST_DIR}/../thirdparty)
 
 # To avoid unnecessary rebuilds set the current branch and

src/openrct2/ReplayManager.cpp

@@ -103,9 +103,10 @@ namespace OpenRCT2
 
     class ReplayManager final : public IReplayManager
     {
-        static constexpr uint16_t kReplayVersion = 10;
+        static constexpr uint16_t kReplayVersion = 11;
+        static constexpr uint16_t kReplayMinCompatVersion = 10;
         static constexpr uint32_t kReplayMagic = 0x5243524F; // ORCR.
-        static constexpr int kReplayCompressionLevel = Compression::kZlibMaxCompressionLevel;
+        static constexpr int kReplayCompressionLevel = 18;
         static constexpr int kNormalRecordingChecksumTicks = 1;
         static constexpr int kSilentRecordingChecksumTicks = 40; // Same as network server
 
@@ -313,8 +314,9 @@ namespace OpenRCT2
 
             MemoryStream compressed;
             stream.SetPosition(0);
-            bool compressStatus = Compression::zlibCompress(
+            // header already has decompressed length, but no checksum, so use the ZStandard checksum
-                stream, stream.GetLength(), compressed, Compression::ZlibHeaderType::zlib, kReplayCompressionLevel);
+            bool compressStatus = Compression::zstdCompress(
+                stream, stream.GetLength(), compressed, Compression::ZstdMetadata::checksum, kReplayCompressionLevel);
             if (!compressStatus)
                 throw IOException("Compression Error");
 
@@ -563,12 +565,18 @@ namespace OpenRCT2
 
                 MemoryStream decompressed;
                 bool decompressStatus = true;
-
                 recFile.data.SetPosition(0);
+                if (recFile.version <= 10)
+                {
                     decompressStatus = Compression::zlibDecompress(
                         recFile.data, recFile.data.GetLength(), decompressed, recFile.uncompressedSize,
                         Compression::ZlibHeaderType::zlib);
-
+                }
+                else
+                {
+                    decompressStatus = Compression::zstdDecompress(
+                        recFile.data, recFile.data.GetLength(), decompressed, recFile.uncompressedSize);
+                }
                 if (!decompressStatus)
                     throw IOException("Decompression Error");
 
@@ -683,7 +691,7 @@ namespace OpenRCT2
 
         bool Compatible(ReplayRecordData& data)
         {
-            return data.version == kReplayVersion;
+            return data.version >= kReplayMinCompatVersion;
         }
 
         bool Serialise(DataSerialiser& serialiser, ReplayRecordData& data)

src/openrct2/command_line/CommandLine.hpp

@@ -108,6 +108,7 @@ consteval CommandLineCommand DefineSubCommand(const char* name, const CommandLin
 namespace OpenRCT2::CommandLine
 {
     extern const CommandLineCommand kRootCommands[];
+    extern const CommandLineCommand kConvertCommands[];
     extern const CommandLineCommand kScreenshotCommands[];
     extern const CommandLineCommand kSpriteCommands[];
     extern const CommandLineCommand kSimulateCommands[];
@@ -118,6 +119,5 @@ namespace OpenRCT2::CommandLine
     void PrintHelp(bool allCommands = false);
     exitcode_t HandleCommandDefault();
 
-    exitcode_t HandleCommandConvert(CommandLineArgEnumerator* enumerator);
     exitcode_t HandleCommandUri(CommandLineArgEnumerator* enumerator);
 } // namespace OpenRCT2::CommandLine

src/openrct2/command_line/ConvertCommand.cpp

@@ -12,6 +12,8 @@
 #include "../GameState.h"
 #include "../OpenRCT2.h"
 #include "../ParkImporter.h"
+#include "../PlatformEnvironment.h"
+#include "../config/Config.h"
 #include "../core/Console.hpp"
 #include "../core/Path.hpp"
 #include "../object/ObjectManager.h"
@@ -20,14 +22,33 @@
 #include "CommandLine.hpp"
 
 #include <cassert>
+#include <limits>
 #include <memory>
 
 using namespace OpenRCT2;
 
+static int32_t _compressLevel = kParkFileSaveCompressionLevel;
+
+// clang-format off
+static constexpr CommandLineOptionDefinition kConvertOptions[]
+{
+    { CMDLINE_TYPE_INTEGER, &_compressLevel, 'l', "compress-level", "The compression level to use when writing the converted file" },
+    kOptionTableEnd
+};
+
+static exitcode_t HandleCommandConvert(CommandLineArgEnumerator* argEnumerator);
+
+const CommandLineCommand CommandLine::kConvertCommands[]{
+    // Main commands
+    DefineCommand("", "<source> [destination]", kConvertOptions, HandleCommandConvert),
+    kCommandTableEnd
+};
+// clang-format on
+
 static void WriteConvertFromAndToMessage(FileExtension sourceFileType, FileExtension destinationFileType);
 static u8string GetFileTypeFriendlyName(FileExtension fileType);
 
-exitcode_t CommandLine::HandleCommandConvert(CommandLineArgEnumerator* enumerator)
+static exitcode_t HandleCommandConvert(CommandLineArgEnumerator* enumerator)
 {
     exitcode_t result = CommandLine::HandleCommandDefault();
     if (result != EXITCODE_CONTINUE)
@@ -48,10 +69,10 @@ exitcode_t CommandLine::HandleCommandConvert(CommandLineArgEnumerator* enumerato
 
     // Get the destination path
     const utf8* rawDestinationPath;
-    if (!enumerator->TryPopString(&rawDestinationPath))
+    if (!enumerator->TryPopString(&rawDestinationPath) || String::startsWith(rawDestinationPath, "-"))
     {
-        Console::Error::WriteLine("Expected a destination path.");
+        // if no destination path is provided, convert the park file in-place
-        return EXITCODE_FAIL;
+        rawDestinationPath = rawSourcePath;
     }
 
     const auto destinationPath = Path::GetAbsolute(rawDestinationPath);
@@ -75,12 +96,12 @@ exitcode_t CommandLine::HandleCommandConvert(CommandLineArgEnumerator* enumerato
         case FileExtension::PARK:
             if (destinationFileType == FileExtension::PARK)
             {
-                Console::Error::WriteLine("File is already an OpenRCT2 saved game or scenario.");
+                Console::Error::WriteLine(
-                return EXITCODE_FAIL;
+                    "File is already an OpenRCT2 saved game or scenario. Updating file version and recompressing.");
             }
             break;
         default:
-            Console::Error::WriteLine("Only conversion from .SC4, .SV4, .SC6 or .SV6 is supported.");
+            Console::Error::WriteLine("Only conversion from .SC4, .SV4, .SC6, .SV6, or .PARK is supported.");
             return EXITCODE_FAIL;
     }
 
@@ -125,7 +146,7 @@ exitcode_t CommandLine::HandleCommandConvert(CommandLineArgEnumerator* enumerato
         auto* windowMgr = Ui::GetWindowManager();
         windowMgr->CloseByClass(WindowClass::MainWindow);
 
-        exporter->Export(gameState, destinationPath);
+        exporter->Export(gameState, destinationPath, static_cast<int16_t>(_compressLevel));
     }
     catch (const std::exception& ex)
     {

src/openrct2/command_line/RootCommands.cpp

@@ -133,7 +133,6 @@ const CommandLineCommand CommandLine::kRootCommands[]
     DefineCommand("join",     "<hostname>",             kStandardOptions, HandleCommandJoin   ),
 #endif
     DefineCommand("set-rct2", "<path>",                 kStandardOptions, HandleCommandSetRCT2),
-    DefineCommand("convert",  "<source> <destination>", kStandardOptions, CommandLine::HandleCommandConvert),
     DefineCommand("scan-objects", "<path>",             kStandardOptions, HandleCommandScanObjects),
     DefineCommand("handle-uri", "openrct2://.../",      kStandardOptions, CommandLine::HandleCommandUri),
 
@@ -142,6 +141,7 @@ const CommandLineCommand CommandLine::kRootCommands[]
 #endif
 
     // Sub-commands
+    DefineSubCommand("convert",         CommandLine::kConvertCommands          ),
     DefineSubCommand("screenshot",      CommandLine::kScreenshotCommands       ),
     DefineSubCommand("sprite",          CommandLine::kSpriteCommands           ),
     DefineSubCommand("simulate",        CommandLine::kSimulateCommands         ),

src/openrct2/command_line/SimulateCommands.cpp

@@ -23,26 +23,36 @@
 
 using namespace OpenRCT2;
 
+// clang-format off
+static constexpr CommandLineOptionDefinition kNoOptions[]
+{
+    kOptionTableEnd
+};
+
 static exitcode_t HandleSimulate(CommandLineArgEnumerator* argEnumerator);
 
-const CommandLineCommand CommandLine::kSimulateCommands[]{ // Main commands
+const CommandLineCommand CommandLine::kSimulateCommands[]{
-                                                           DefineCommand("", "<ticks>", nullptr, HandleSimulate),
+    // Main commands
+    DefineCommand("", "<park file> <ticks>", kNoOptions, HandleSimulate),
     kCommandTableEnd
 };
+// clang-format on
 
 static exitcode_t HandleSimulate(CommandLineArgEnumerator* argEnumerator)
 {
-    const char** argv = const_cast<const char**>(argEnumerator->GetArguments()) + argEnumerator->GetIndex();
+    const utf8* inputPath;
-    int32_t argc = argEnumerator->GetCount() - argEnumerator->GetIndex();
+    if (!argEnumerator->TryPopString(&inputPath))
-
-    if (argc < 2)
     {
-        Console::Error::WriteLine("Missing arguments <sv6-file> <ticks>.");
+        Console::Error::WriteLine("Expected a save file path");
         return EXITCODE_FAIL;
     }
 
-    const char* inputPath = argv[0];
+    int32_t ticks;
-    uint32_t ticks = atol(argv[1]);
+    if (!argEnumerator->TryPopInteger(&ticks))
+    {
+        Console::Error::WriteLine("Expected a number of ticks to simulate");
+        return EXITCODE_FAIL;
+    }
 
     gOpenRCT2Headless = true;
 
@@ -59,7 +69,7 @@ static exitcode_t HandleSimulate(CommandLineArgEnumerator* argEnumerator)
         }
 
         Console::WriteLine("Running %d ticks...", ticks);
-        for (uint32_t i = 0; i < ticks; i++)
+        for (int32_t i = 0; i < ticks; i++)
         {
             gameStateUpdateLogic();
         }

src/openrct2/core/Compression.cpp

@@ -19,12 +19,13 @@
 
 #include <limits>
 #include <zlib.h>
+#include <zstd.h>
 
 namespace OpenRCT2::Compression
 {
-    constexpr size_t kZlibChunkSize = 128 * 1024;
+    static constexpr size_t kZlibChunkSize = 128 * 1024;
-    constexpr size_t kZlibMaxChunkSize = static_cast<size_t>(std::numeric_limits<uInt>::max());
+    static constexpr size_t kZlibMaxChunkSize = static_cast<size_t>(std::numeric_limits<uInt>::max());
-    constexpr int kZlibWindowBits[] = { -15, 15, 15 + 16 };
+    static constexpr int kZlibWindowBits[] = { -15, 15, 15 + 16 };
 
     /*
      * Modified copy of compressBound() from zlib 1.3.1, with the argument type changed from ULong
@@ -32,7 +33,7 @@ namespace OpenRCT2::Compression
      */
     static uint64_t zlibCompressBound(uint64_t length)
     {
-        return length + (length >> 12) + (length >> 14) + (length >> 25) + 13 + (18 - 6);
+        return length + (length >> 12) + (length >> 14) + (length >> 25) + 13uLL + (18uLL - 6uLL);
     }
 
     bool zlibCompress(IStream& source, uint64_t sourceLength, IStream& dest, ZlibHeaderType header, int16_t level)
@@ -138,4 +139,137 @@ namespace OpenRCT2::Compression
         inflateEnd(&strm);
         return true;
     }
+
+    /*
+     * Modified copy of ZSTD_COMPRESSBOUND / ZSTD_compressBound() from zstd 1.5.7, with the argument
+     * type changed from size_t (which may be only 32 bits) to uint64_t, and removes the error handling.
+     */
+    static uint64_t zstdCompressBound(uint64_t length)
+    {
+        return length + (length >> 8)
+            + ((length < (128uLL << 10)) ? (((128uLL << 10) - length) >> 11) /* margin, from 64 to 0 */ : 0uLL);
+    }
+
+    bool zstdCompress(IStream& source, uint64_t sourceLength, IStream& dest, ZstdMetadata metadata, int16_t level)
+    {
+        Guard::Assert(sourceLength <= source.GetLength() - source.GetPosition());
+
+        size_t ret;
+        StreamReadBuffer sourceBuf(source, sourceLength, ZSTD_CStreamInSize());
+        StreamWriteBuffer destBuf(dest, zstdCompressBound(sourceLength), ZSTD_CStreamOutSize());
+        unsigned metaFlags = static_cast<unsigned>(metadata);
+
+        const auto deleter = [](ZSTD_CCtx* ptr) { ZSTD_freeCCtx(ptr); };
+        std::unique_ptr<ZSTD_CCtx, decltype(deleter)> ctx(ZSTD_createCCtx(), deleter);
+        if (ctx == nullptr)
+        {
+            LOG_ERROR("Failed to create zstd context");
+            return false;
+        }
+
+        ret = ZSTD_CCtx_setParameter(ctx.get(), ZSTD_c_compressionLevel, level);
+        if (ZSTD_isError(ret))
+        {
+            LOG_ERROR("Failed to set compression level with error: %s", ZSTD_getErrorName(ret));
+            return false;
+        }
+        // set options for content size (default on) and checksum (default off)
+        ret = ZSTD_CCtx_setParameter(ctx.get(), ZSTD_c_contentSizeFlag, (metaFlags & 1) != 0);
+        if (ZSTD_isError(ret))
+        {
+            LOG_ERROR("Failed to set content size flag with error: %s", ZSTD_getErrorName(ret));
+            return false;
+        }
+        ret = ZSTD_CCtx_setParameter(ctx.get(), ZSTD_c_checksumFlag, (metaFlags & 2) != 0);
+        if (ZSTD_isError(ret))
+        {
+            LOG_ERROR("Failed to set checksum flag with error: %s", ZSTD_getErrorName(ret));
+            return false;
+        }
+        // unlike gzip, zstd puts the decompressed content size at the start of the file,
+        // so we need to tell zstd how big the input is before we start compressing.
+        ret = ZSTD_CCtx_setPledgedSrcSize(ctx.get(), sourceLength);
+        if (ZSTD_isError(ret))
+        {
+            LOG_ERROR("Failed to set file length with error: %s", ZSTD_getErrorName(ret));
+            return false;
+        }
+
+        do
+        {
+            auto readBlock = sourceBuf.ReadBlock(source);
+            ZSTD_inBuffer input = { readBlock.first, readBlock.second, 0 };
+
+            do
+            {
+                Guard::Assert(destBuf, "Compression Overruns Ouput Size");
+
+                auto writeBlock = destBuf.WriteBlockStart();
+                ZSTD_outBuffer output = { writeBlock.first, writeBlock.second, 0 };
+
+                ret = ZSTD_compressStream2(ctx.get(), &output, &input, sourceBuf ? ZSTD_e_continue : ZSTD_e_end);
+                if (ZSTD_isError(ret))
+                {
+                    LOG_ERROR("Failed to compress data with error: %s", ZSTD_getErrorName(ret));
+                    return false;
+                }
+
+                destBuf.WriteBlockCommit(dest, output.pos);
+            } while (input.pos < input.size || (!sourceBuf && ret > 0));
+        } while (sourceBuf);
+
+        return true;
+    }
+
+    bool zstdDecompress(IStream& source, uint64_t sourceLength, IStream& dest, uint64_t decompressLength)
+    {
+        Guard::Assert(sourceLength <= source.GetLength() - source.GetPosition());
+
+        size_t ret;
+        StreamReadBuffer sourceBuf(source, sourceLength, ZSTD_DStreamInSize());
+        StreamWriteBuffer destBuf(dest, decompressLength, ZSTD_DStreamOutSize());
+
+        const auto deleter = [](ZSTD_DCtx* ptr) { ZSTD_freeDCtx(ptr); };
+        std::unique_ptr<ZSTD_DCtx, decltype(deleter)> ctx(ZSTD_createDCtx(), deleter);
+        if (ctx == nullptr)
+        {
+            LOG_ERROR("Failed to create zstd context");
+            return false;
+        }
+
+        do
+        {
+            auto readBlock = sourceBuf.ReadBlock(source);
+            ZSTD_inBuffer input = { readBlock.first, readBlock.second, 0 };
+
+            do
+            {
+                if (!destBuf)
+                {
+                    LOG_ERROR("Decompressed data larger than expected");
+                    return false;
+                }
+
+                auto writeBlock = destBuf.WriteBlockStart();
+                ZSTD_outBuffer output = { writeBlock.first, writeBlock.second, 0 };
+
+                ret = ZSTD_decompressStream(ctx.get(), &output, &input);
+                if (ZSTD_isError(ret))
+                {
+                    LOG_ERROR("Failed to compress data with error: %s", ZSTD_getErrorName(ret));
+                    return false;
+                }
+
+                destBuf.WriteBlockCommit(dest, output.pos);
+            } while (input.pos < input.size || (!sourceBuf && ret > 0));
+        } while (sourceBuf);
+
+        if (destBuf)
+        {
+            LOG_ERROR("Decompressed data smaller than expected");
+            return false;
+        }
+
+        return true;
+    }
 } // namespace OpenRCT2::Compression

src/openrct2/core/Compression.h

@@ -17,7 +17,7 @@
 
 namespace OpenRCT2::Compression
 {
-    // zlib doesn't use 0 as a real compression level, so use it to mean no compression
+    // both zlib and zstd don't use 0 as a real compression level, so use it to mean no compression
     constexpr int16_t kNoCompressionLevel = 0;
 
     // Zlib methods, using the DEFLATE compression algorithm
@@ -36,4 +36,22 @@ namespace OpenRCT2::Compression
         int16_t level = kZlibDefaultCompressionLevel);
     bool zlibDecompress(
         IStream& source, uint64_t sourceLength, IStream& dest, uint64_t decompressLength, ZlibHeaderType header);
+
+    // Zstd methods, using the ZStandard compression algorithm
+    constexpr int16_t kZstdDefaultCompressionLevel = 3;
+
+    // Options for optional metadata to attach to a ZStandard frame. Zstd default is length-only,
+    // but callers to zstdCompress should use whatever is not already duplicated by other headers.
+    enum class ZstdMetadata
+    {
+        none = 0,
+        length = 1,
+        checksum = 2,
+        both = 3,
+    };
+
+    bool zstdCompress(
+        IStream& source, uint64_t sourceLength, IStream& dest, ZstdMetadata metadata,
+        int16_t level = kZstdDefaultCompressionLevel);
+    bool zstdDecompress(IStream& source, uint64_t sourceLength, IStream& dest, uint64_t decompressLength);
 } // namespace OpenRCT2::Compression

src/openrct2/core/OrcaStream.hpp

@@ -41,6 +41,7 @@ namespace OpenRCT2
         {
             none,
             gzip,
+            zstd,
         };
 
     private:
@@ -76,7 +77,7 @@ namespace OpenRCT2
         int16_t _compressionLevel;
 
     public:
-        OrcaStream(IStream& stream, const Mode mode, int16_t compressionLevel = Compression::kZlibDefaultCompressionLevel)
+        OrcaStream(IStream& stream, const Mode mode, int16_t compressionLevel = Compression::kNoCompressionLevel)
         {
             _stream = &stream;
             _mode = mode;
@@ -104,6 +105,10 @@ namespace OpenRCT2
                                 *_stream, _header.CompressedSize, _buffer, _header.UncompressedSize,
                                 Compression::ZlibHeaderType::gzip);
                             break;
+                        case CompressionType::zstd:
+                            decompressStatus = Compression::zstdDecompress(
+                                *_stream, _header.CompressedSize, _buffer, _header.UncompressedSize);
+                            break;
                         default:
                             throw IOException("Unknown Park Compression Type");
                     }
@@ -131,7 +136,7 @@ namespace OpenRCT2
             {
                 _header = {};
                 _header.Compression = _compressionLevel == Compression::kNoCompressionLevel ? CompressionType::none
-                                                                                            : CompressionType::gzip;
+                                                                                            : CompressionType::zstd;
                 _buffer = MemoryStream{};
             }
         }
@@ -163,6 +168,11 @@ namespace OpenRCT2
                             compressStatus = Compression::zlibCompress(
                                 _buffer, _buffer.GetLength(), compressed, Compression::ZlibHeaderType::gzip, _compressionLevel);
                             break;
+                        case CompressionType::zstd:
+                            // PARK header already has length and checksum, so exclude them in the compression frame
+                            compressStatus = Compression::zstdCompress(
+                                _buffer, _buffer.GetLength(), compressed, Compression::ZstdMetadata::none, _compressionLevel);
+                            break;
                         default:
                             break;
                     }

src/openrct2/network/NetworkBase.cpp

@@ -49,7 +49,7 @@ using namespace OpenRCT2;
 // It is used for making sure only compatible builds get connected, even within
 // single OpenRCT2 version.
 
-constexpr uint8_t kNetworkStreamVersion = 0;
+constexpr uint8_t kNetworkStreamVersion = 1;
 
 const std::string kNetworkStreamID = std::string(kOpenRCT2Version) + "-" + std::to_string(kNetworkStreamVersion);
 
@@ -2876,7 +2876,7 @@ bool NetworkBase::SaveMap(IStream* stream, const std::vector<const ObjectReposit
         exporter->ExportObjectsList = objects;
 
         auto& gameState = getGameState();
-        exporter->Export(gameState, *stream);
+        exporter->Export(gameState, *stream, kParkFileNetCompressionLevel);
         result = true;
     }
     catch (const std::exception& e)

src/openrct2/park/ParkFile.cpp

@@ -17,6 +17,7 @@
 #include "../OpenRCT2.h"
 #include "../ParkImporter.h"
 #include "../Version.h"
+#include "../config/Config.h"
 #include "../core/Console.hpp"
 #include "../core/Crypt.h"
 #include "../core/DataSerialiser.h"
@@ -2766,7 +2767,7 @@ int32_t ScenarioSave(GameState_t& gameState, u8string_view path, int32_t flags)
         {
             // s6exporter->SaveGame(path);
         }
-        parkFile->Save(gameState, path, Compression::kZlibDefaultCompressionLevel);
+        parkFile->Save(gameState, path, gIsAutosave ? kParkFileAutoCompressionLevel : kParkFileSaveCompressionLevel);
         result = true;
     }
     catch (const std::exception& e)

src/openrct2/park/ParkFile.h

@@ -22,10 +22,10 @@ namespace OpenRCT2
     struct GameState_t;
 
     // Current version that is saved.
-    constexpr uint32_t kParkFileCurrentVersion = 56;
+    constexpr uint32_t kParkFileCurrentVersion = 57;
 
     // The minimum version that is forwards compatible with the current version.
-    constexpr uint32_t kParkFileMinVersion = 55;
+    constexpr uint32_t kParkFileMinVersion = 57;
 
     // The minimum version that is backwards compatible with the current version.
     // If this is increased beyond 0, uncomment the checks in ParkFile.cpp and Context.cpp!
@@ -33,6 +33,11 @@ namespace OpenRCT2
 
     constexpr uint32_t kParkFileMagic = 0x4B524150; // PARK
 
+    // ZStd compression levels to use for various types of saves
+    constexpr int16_t kParkFileSaveCompressionLevel = 7;
+    constexpr int16_t kParkFileAutoCompressionLevel = 4;
+    constexpr int16_t kParkFileNetCompressionLevel = 4;
+
     struct IStream;
 
     // As uint16_t, in order to allow comparison with int32_t
@@ -62,11 +67,7 @@ namespace OpenRCT2
     public:
         std::vector<const ObjectRepositoryItem*> ExportObjectsList;
 
-        void Export(
+        void Export(OpenRCT2::GameState_t& gameState, std::string_view path, int16_t compressionLevel);
-            OpenRCT2::GameState_t& gameState, std::string_view path,
+        void Export(OpenRCT2::GameState_t& gameState, OpenRCT2::IStream& stream, int16_t compressionLevel);
-            int16_t compressionLevel = Compression::kZlibDefaultCompressionLevel);
-        void Export(
-            OpenRCT2::GameState_t& gameState, OpenRCT2::IStream& stream,
-            int16_t compressionLevel = Compression::kZlibDefaultCompressionLevel);
     };
 } // namespace OpenRCT2

src/openrct2/platform/Crash.cpp

@@ -139,6 +139,8 @@ static bool OnCrash(
         FileStream source(dumpFilePath, FileMode::open);
         FileStream dest(dumpFilePathGZIP, FileMode::write);
 
+        // We could switch this to zstdCompress() if supported by backtrace.io. If you switch it,
+        // use the extension .zst and ZstdMetadataType::both to use the appropriate metadata.
         if (Compression::zlibCompress(source, source.GetLength(), dest, Compression::ZlibHeaderType::gzip))
         {
             // TODO: enable upload of gzip-compressed dumps once supported on
@@ -183,7 +185,7 @@ static bool OnCrash(
         exporter->ExportObjectsList = objManager.GetPackableObjects();
 
         auto& gameState = getGameState();
-        exporter->Export(gameState, saveFilePathUTF8.c_str());
+        exporter->Export(gameState, saveFilePathUTF8.c_str(), kParkFileSaveCompressionLevel);
         savedGameDumped = true;
     }
     catch (const std::exception& e)

test/tests/S6ImportExportTests.cpp

@@ -120,7 +120,7 @@ static bool ExportSave(MemoryStream& stream, std::unique_ptr<IContext>& context)
     exporter->ExportObjectsList = objManager.GetPackableObjects();
 
     auto& gameState = getGameState();
-    exporter->Export(gameState, stream);
+    exporter->Export(gameState, stream, OpenRCT2::kParkFileSaveCompressionLevel);
 
     return true;
 }