From 8f67d6a4440bf23e882db1a2424aaf814a3cf7d9 Mon Sep 17 00:00:00 2001
From: James Rowe <jroweboy@gmail.com>
Date: Sat, 7 Sep 2019 15:15:04 -0600
Subject: [PATCH] Add ZSTD compression for precompiled cache

---
 .gitmodules                     |  3 ++
 externals/CMakeLists.txt        |  4 +++
 externals/zstd                  |  1 +
 src/common/zstd_compression.cpp | 51 +++++++++++++++++++++++++++++++++
 src/common/zstd_compression.h   | 44 ++++++++++++++++++++++++++++
 5 files changed, 103 insertions(+)
 create mode 160000 externals/zstd
 create mode 100644 src/common/zstd_compression.cpp
 create mode 100644 src/common/zstd_compression.h

diff --git a/.gitmodules b/.gitmodules
index 0dc4538c1..b247ccdbe 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -46,3 +46,6 @@
 [submodule "lodepng"]
     path = externals/lodepng/lodepng
     url = https://github.com/lvandeve/lodepng.git
+[submodule "zstd"]
+    path = externals/zstd
+    url = https://github.com/facebook/zstd.git
diff --git a/externals/CMakeLists.txt b/externals/CMakeLists.txt
index 2ae4c33f9..63159a52b 100644
--- a/externals/CMakeLists.txt
+++ b/externals/CMakeLists.txt
@@ -62,6 +62,10 @@ if (ARCHITECTURE_x86_64)
     target_compile_definitions(xbyak INTERFACE XBYAK_NO_OP_NAMES)
 endif()
 
+# Zstandard
+add_subdirectory(zstd/build/cmake EXCLUDE_FROM_ALL)
+target_include_directories(libzstd_static INTERFACE ./zstd/lib)
+
 # ENet
 add_subdirectory(enet)
 target_include_directories(enet INTERFACE ./enet/include)
diff --git a/externals/zstd b/externals/zstd
new file mode 160000
index 000000000..470344d33
--- /dev/null
+++ b/externals/zstd
@@ -0,0 +1 @@
+Subproject commit 470344d33e1d52a2ada75d278466da8d4ee2faf6
diff --git a/src/common/zstd_compression.cpp b/src/common/zstd_compression.cpp
new file mode 100644
index 000000000..23263ce30
--- /dev/null
+++ b/src/common/zstd_compression.cpp
@@ -0,0 +1,51 @@
+// Copyright 2019 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#include <algorithm>
+#include <zstd.h>
+
+#include "common/assert.h"
+#include "common/zstd_compression.h"
+
+namespace Common::Compression {
+
+std::vector<u8> CompressDataZSTD(const u8* source, std::size_t source_size, s32 compression_level) {
+    compression_level = std::clamp(compression_level, 1, ZSTD_maxCLevel());
+
+    const std::size_t max_compressed_size = ZSTD_compressBound(source_size);
+    std::vector<u8> compressed(max_compressed_size);
+
+    const std::size_t compressed_size =
+        ZSTD_compress(compressed.data(), compressed.size(), source, source_size, compression_level);
+
+    if (ZSTD_isError(compressed_size)) {
+        // Compression failed
+        return {};
+    }
+
+    compressed.resize(compressed_size);
+
+    return compressed;
+}
+
+std::vector<u8> CompressDataZSTDDefault(const u8* source, std::size_t source_size) {
+    return CompressDataZSTD(source, source_size, ZSTD_CLEVEL_DEFAULT);
+}
+
+std::vector<u8> DecompressDataZSTD(const std::vector<u8>& compressed) {
+    const std::size_t decompressed_size =
+        ZSTD_getDecompressedSize(compressed.data(), compressed.size());
+    std::vector<u8> decompressed(decompressed_size);
+
+    const std::size_t uncompressed_result_size = ZSTD_decompress(
+        decompressed.data(), decompressed.size(), compressed.data(), compressed.size());
+
+    if (decompressed_size != uncompressed_result_size || ZSTD_isError(uncompressed_result_size)) {
+        // Decompression failed
+        return {};
+    }
+    return decompressed;
+}
+
+} // namespace Common::Compression
\ No newline at end of file
diff --git a/src/common/zstd_compression.h b/src/common/zstd_compression.h
new file mode 100644
index 000000000..e9de941c8
--- /dev/null
+++ b/src/common/zstd_compression.h
@@ -0,0 +1,44 @@
+// Copyright 2019 yuzu Emulator Project
+// Licensed under GPLv2 or any later version
+// Refer to the license.txt file included.
+
+#pragma once
+
+#include <vector>
+
+#include "common/common_types.h"
+
+namespace Common::Compression {
+
+/**
+ * Compresses a source memory region with Zstandard and returns the compressed data in a vector.
+ *
+ * @param source the uncompressed source memory region.
+ * @param source_size the size in bytes of the uncompressed source memory region.
+ * @param compression_level the used compression level. Should be between 1 and 22.
+ *
+ * @return the compressed data.
+ */
+std::vector<u8> CompressDataZSTD(const u8* source, std::size_t source_size, s32 compression_level);
+
+/**
+ * Compresses a source memory region with Zstandard with the default compression level and returns
+ * the compressed data in a vector.
+ *
+ * @param source the uncompressed source memory region.
+ * @param source_size the size in bytes of the uncompressed source memory region.
+ *
+ * @return the compressed data.
+ */
+std::vector<u8> CompressDataZSTDDefault(const u8* source, std::size_t source_size);
+
+/**
+ * Decompresses a source memory region with Zstandard and returns the uncompressed data in a vector.
+ *
+ * @param compressed the compressed source memory region.
+ *
+ * @return the decompressed data.
+ */
+std::vector<u8> DecompressDataZSTD(const std::vector<u8>& compressed);
+
+} // namespace Common::Compression
\ No newline at end of file