From 74cee1b65d1c27006c44051c7c8228bbb4827eb7 Mon Sep 17 00:00:00 2001
From: unknown <FreddyFunk@users.noreply.github.com>
Date: Thu, 7 Feb 2019 19:18:49 +0100
Subject: [PATCH] gl_shader_disk_cache: Use better compression for transferable
 and precompiled shader disk chache files

---
 src/common/data_compression.cpp               | 24 +++++++++++++------
 src/common/data_compression.h                 |  8 ++++++-
 .../renderer_opengl/gl_shader_disk_cache.cpp  |  4 ++--
 3 files changed, 26 insertions(+), 10 deletions(-)

diff --git a/src/common/data_compression.cpp b/src/common/data_compression.cpp
index 624b8ac47b..fdf4907d13 100644
--- a/src/common/data_compression.cpp
+++ b/src/common/data_compression.cpp
@@ -4,14 +4,14 @@
 
 #pragma once
 
-#include <lz4.h>
+#include <lz4hc.h>
 
 #include "data_compression.h"
 
 namespace Compression {
 
-
-std::vector<u8> CompressDataLZ4(const u8* source, std::size_t source_size) {
+std::vector<u8> CompressDataLZ4(const u8* source, std::size_t source_size,
+                                bool use_LZ4_high_compression) {
     if (source_size > LZ4_MAX_INPUT_SIZE) {
         // Source size exceeds LZ4 maximum input size
         return {};
@@ -19,9 +19,18 @@ std::vector<u8> CompressDataLZ4(const u8* source, std::size_t source_size) {
     const auto source_size_int = static_cast<int>(source_size);
     const int max_compressed_size = LZ4_compressBound(source_size_int);
     std::vector<u8> compressed(max_compressed_size);
-    const int compressed_size = LZ4_compress_default(reinterpret_cast<const char*>(source),
-                                                     reinterpret_cast<char*>(compressed.data()),
-                                                     source_size_int, max_compressed_size);
+    int compressed_size = 0;
+
+    if (use_LZ4_high_compression) {
+        compressed_size = LZ4_compress_HC(reinterpret_cast<const char*>(source),
+                                          reinterpret_cast<char*>(compressed.data()),
+                                          source_size_int, max_compressed_size, LZ4HC_CLEVEL_MAX);
+    } else {
+        compressed_size = LZ4_compress_default(reinterpret_cast<const char*>(source),
+                                               reinterpret_cast<char*>(compressed.data()),
+                                               source_size_int, max_compressed_size);
+    }
+
     if (compressed_size <= 0) {
         // Compression failed
         return {};
@@ -30,7 +39,8 @@ std::vector<u8> CompressDataLZ4(const u8* source, std::size_t source_size) {
     return compressed;
 }
 
-std::vector<u8> DecompressDataLZ4(const std::vector<u8>& compressed, std::size_t uncompressed_size) {
+std::vector<u8> DecompressDataLZ4(const std::vector<u8>& compressed,
+                                  std::size_t uncompressed_size) {
     std::vector<u8> uncompressed(uncompressed_size);
     const int size_check = LZ4_decompress_safe(reinterpret_cast<const char*>(compressed.data()),
                                                reinterpret_cast<char*>(uncompressed.data()),
diff --git a/src/common/data_compression.h b/src/common/data_compression.h
index 70878b8d9c..f7264b7b85 100644
--- a/src/common/data_compression.h
+++ b/src/common/data_compression.h
@@ -10,7 +10,13 @@
 
 namespace Compression {
 
-std::vector<u8> CompressDataLZ4(const u8* source, std::size_t source_size);
+// Compresses a source memory region with LZ4 and returns the compressed data in an vector. If
+// use_LZ4_high_compression is true, the LZ4 subalgortihmn LZ4HC is used with the highst possible
+// compression level. This results in a smaller compressed size, but requires more CPU time for
+// compression. Data compressed with LZ4HC can also be decompressed with the default LZ4
+// decompression function.
+std::vector<u8> CompressDataLZ4(const u8* source, std::size_t source_size,
+                                bool use_LZ4_high_compression);
 
 std::vector<u8> DecompressDataLZ4(const std::vector<u8>& compressed, std::size_t uncompressed_size);
 
diff --git a/src/video_core/renderer_opengl/gl_shader_disk_cache.cpp b/src/video_core/renderer_opengl/gl_shader_disk_cache.cpp
index a74b66a90b..0c8001b193 100644
--- a/src/video_core/renderer_opengl/gl_shader_disk_cache.cpp
+++ b/src/video_core/renderer_opengl/gl_shader_disk_cache.cpp
@@ -475,7 +475,7 @@ void ShaderDiskCacheOpenGL::SaveDecompiled(u64 unique_identifier, const std::str
         return;
 
     const std::vector<u8> compressed_code{
-        Compression::CompressDataLZ4(reinterpret_cast<const u8*>(code.data()), code.size())};
+        Compression::CompressDataLZ4(reinterpret_cast<const u8*>(code.data()), code.size(), true)};
     if (compressed_code.empty()) {
         LOG_ERROR(Render_OpenGL, "Failed to compress GLSL code - skipping shader {:016x}",
                   unique_identifier);
@@ -506,7 +506,7 @@ void ShaderDiskCacheOpenGL::SaveDump(const ShaderDiskCacheUsage& usage, GLuint p
     glGetProgramBinary(program, binary_length, nullptr, &binary_format, binary.data());
 
     const std::vector<u8> compressed_binary =
-        Compression::CompressDataLZ4(binary.data(), binary.size());
+        Compression::CompressDataLZ4(binary.data(), binary.size(), true);
 
     if (compressed_binary.empty()) {
         LOG_ERROR(Render_OpenGL, "Failed to compress binary program in shader={:016x}",