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: 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 +++++++-
 2 files changed, 24 insertions(+), 8 deletions(-)

(limited to 'src/common')

diff --git a/src/common/data_compression.cpp b/src/common/data_compression.cpp
index 624b8ac47..fdf4907d1 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 70878b8d9..f7264b7b8 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);
 
-- 
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