From c1d7fa7e8b3db197fcfb95c0c78f14718d2e7437 Mon Sep 17 00:00:00 2001
From: robert-yates <robert-yates@users.noreply.github.com>
Date: Sat, 11 Jan 2025 16:32:44 +0100
Subject: [PATCH] add compression utils

---
 .gitmodules                      |   5 ++
 deps/CMakeLists.txt              |   1 +
 deps/zlib                        |   1 +
 deps/zlib.cmake                  |   4 ++
 src/common/CMakeLists.txt        |   1 +
 src/common/utils/compression.cpp | 105 +++++++++++++++++++++++++++++++
 src/common/utils/compression.hpp |  16 +++++
 7 files changed, 133 insertions(+)
 create mode 160000 deps/zlib
 create mode 100644 deps/zlib.cmake
 create mode 100644 src/common/utils/compression.cpp
 create mode 100644 src/common/utils/compression.hpp

diff --git a/.gitmodules b/.gitmodules
index 21cf3d31..9f7d3d9a 100644
--- a/.gitmodules
+++ b/.gitmodules
@@ -14,3 +14,8 @@
 [submodule "deps/googletest"]
 	path = deps/googletest
 	url = https://github.com/google/googletest.git
+[submodule "deps/zlib"]
+	path = deps/zlib
+	url = https://github.com/madler/zlib.git
+	branch = develop
+	ignore = dirty
\ No newline at end of file
diff --git a/deps/CMakeLists.txt b/deps/CMakeLists.txt
index 8d55e778..168d6006 100644
--- a/deps/CMakeLists.txt
+++ b/deps/CMakeLists.txt
@@ -13,3 +13,4 @@ target_include_directories(reflect INTERFACE
 
 include(mini-gdbstub.cmake)
 include(googletest.cmake)
+include(zlib.cmake)
diff --git a/deps/zlib b/deps/zlib
new file mode 160000
index 00000000..ef24c4c7
--- /dev/null
+++ b/deps/zlib
@@ -0,0 +1 @@
+Subproject commit ef24c4c7502169f016dcd2a26923dbaf3216748c
diff --git a/deps/zlib.cmake b/deps/zlib.cmake
new file mode 100644
index 00000000..b2f92fb6
--- /dev/null
+++ b/deps/zlib.cmake
@@ -0,0 +1,4 @@
+set(ZLIB_BUILD_EXAMPLES OFF CACHE BOOL "" FORCE)
+add_subdirectory(zlib)
+target_compile_definitions(zlibstatic PUBLIC ZLIB_CONST=1)
+target_include_directories(zlibstatic PUBLIC ${zlib_SOURCE_DIR} ${zlib_BINARY_DIR})
\ No newline at end of file
diff --git a/src/common/CMakeLists.txt b/src/common/CMakeLists.txt
index 42753b78..dfc64b78 100644
--- a/src/common/CMakeLists.txt
+++ b/src/common/CMakeLists.txt
@@ -13,4 +13,5 @@ set(THREADS_PREFER_PTHREAD_FLAG ON)
 find_package(Threads REQUIRED)
 target_link_libraries(emulator-common PUBLIC
   Threads::Threads
+  zlibstatic
 )
diff --git a/src/common/utils/compression.cpp b/src/common/utils/compression.cpp
new file mode 100644
index 00000000..a9d03b2a
--- /dev/null
+++ b/src/common/utils/compression.cpp
@@ -0,0 +1,105 @@
+#include "compression.hpp"
+
+#include <zlib.h>
+#include <cstring>
+
+namespace utils::compression
+{
+    namespace zlib
+    {
+        namespace
+        {
+            class zlib_stream
+            {
+              public:
+                zlib_stream()
+                {
+                    memset(&stream_, 0, sizeof(stream_));
+                    valid_ = inflateInit(&stream_) == Z_OK;
+                }
+
+                zlib_stream(zlib_stream&&) = delete;
+                zlib_stream(const zlib_stream&) = delete;
+                zlib_stream& operator=(zlib_stream&&) = delete;
+                zlib_stream& operator=(const zlib_stream&) = delete;
+
+                ~zlib_stream()
+                {
+                    if (valid_)
+                    {
+                        inflateEnd(&stream_);
+                    }
+                }
+
+                z_stream& get()
+                {
+                    return stream_; //
+                }
+
+                bool is_valid() const
+                {
+                    return valid_;
+                }
+
+              private:
+                bool valid_{false};
+                z_stream stream_{};
+            };
+        }
+
+        std::vector<std::uint8_t> decompress(const std::vector<std::uint8_t>& data)
+        {
+            std::vector<std::uint8_t> buffer{};
+            zlib_stream stream_container{};
+            if (!stream_container.is_valid())
+            {
+                return {};
+            }
+
+            int ret{};
+            size_t offset = 0;
+            static thread_local uint8_t dest[CHUNK] = {0};
+            auto& stream = stream_container.get();
+
+            do
+            {
+                const auto input_size = std::min(sizeof(dest), data.size() - offset);
+                stream.avail_in = static_cast<uInt>(input_size);
+                stream.next_in = reinterpret_cast<const Bytef*>(data.data()) + offset;
+                offset += stream.avail_in;
+
+                do
+                {
+                    stream.avail_out = sizeof(dest);
+                    stream.next_out = dest;
+
+                    ret = inflate(&stream, Z_NO_FLUSH);
+                    if (ret != Z_OK && ret != Z_STREAM_END)
+                    {
+                        return {};
+                    }
+
+                    buffer.insert(buffer.end(), dest, dest + sizeof(dest) - stream.avail_out);
+                } while (stream.avail_out == 0);
+            } while (ret != Z_STREAM_END);
+
+            return buffer;
+        }
+
+        std::vector<std::uint8_t> compress(const std::vector<std::uint8_t>& data)
+        {
+            std::vector<std::uint8_t> result{};
+            auto length = compressBound(static_cast<uLong>(data.size()));
+            result.resize(length);
+
+            if (compress2(reinterpret_cast<Bytef*>(result.data()), &length, reinterpret_cast<const Bytef*>(data.data()),
+                          static_cast<uLong>(data.size()), Z_BEST_COMPRESSION) != Z_OK)
+            {
+                return {};
+            }
+
+            result.resize(length);
+            return result;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/common/utils/compression.hpp b/src/common/utils/compression.hpp
new file mode 100644
index 00000000..ec423368
--- /dev/null
+++ b/src/common/utils/compression.hpp
@@ -0,0 +1,16 @@
+#pragma once
+
+#include <string>
+#include <vector>
+#include <cstdint>
+
+#define CHUNK 16384u
+
+namespace utils::compression
+{
+    namespace zlib
+    {
+        std::vector<std::uint8_t> compress(const std::vector<std::uint8_t>& data);
+        std::vector<std::uint8_t> decompress(const std::vector<std::uint8_t>& data);
+    }
+};
\ No newline at end of file