Unpack now works.

.gitignore

@@ -107,6 +107,9 @@ Temporary Items
 *.userosscache
 *.sln.docstates
 
+# Intermediate test files/data
+test/unpack
+
 # User-specific files (MonoDevelop/Xamarin Studio)
 *.userprefs
 

Win32/xPlatAppx/xPlatAppx.vcxproj

@@ -144,6 +144,7 @@
     <ClInclude Include="..\..\lib\zlib\zlib.h" />
     <ClInclude Include="..\..\src\inc\Base64Stream.hpp" />
     <ClInclude Include="..\..\src\inc\CRC32Stream.hpp" />
+    <ClInclude Include="..\..\src\inc\DirectoryObject.hpp" />
     <ClInclude Include="..\..\src\inc\Exceptions.hpp" />
     <ClInclude Include="..\..\src\inc\FileStream.hpp" />
     <ClInclude Include="..\..\src\inc\OffsetStream.hpp" />
@@ -159,7 +160,9 @@
     <None Include="xPlatAppx.def" />
   </ItemGroup>
   <ItemGroup>
+    <ClCompile Include="..\..\src\xPlatAppx\PAL\FileSystem\Win32\DirectoryObject.cpp" />
     <ClCompile Include="..\..\src\xPlatAppx\xPlatAppx.cpp" />
+    <ClCompile Include="..\..\src\xPlatAppx\ZipFileStream.cpp" />
     <ClCompile Include="..\..\src\xPlatAppx\ZipObject.cpp" />
   </ItemGroup>
   <Import Project="$(VCTargetsPath)\Microsoft.Cpp.targets" />

Win32/xPlatAppx/xPlatAppx.vcxproj.filters

@@ -54,6 +54,9 @@
     <ClInclude Include="..\..\src\inc\ZipObject.hpp">
       <Filter>Header Files</Filter>
     </ClInclude>
+    <ClInclude Include="..\..\src\inc\DirectoryObject.hpp">
+      <Filter>Header Files</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <None Include="xPlatAppx.def">
@@ -67,5 +70,11 @@
     <ClCompile Include="..\..\src\xPlatAppx\ZipObject.cpp">
       <Filter>Source Files</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\src\xPlatAppx\PAL\FileSystem\Win32\DirectoryObject.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="..\..\src\xPlatAppx\ZipFileStream.cpp">
+      <Filter>Source Files</Filter>
+    </ClCompile>
   </ItemGroup>
 </Project>

src/inc/DirectoryObject.hpp

@@ -0,0 +1,31 @@
+#pragma once
+
+#include <string>
+#include <vector>
+#include <map>
+#include <memory>
+
+#include "Exceptions.hpp"
+#include "StreamBase.hpp"
+#include "StorageObject.hpp"
+
+namespace xPlat {
+
+    class DirectoryObject : public StorageObject
+    {
+    public:
+        DirectoryObject(std::string root) : m_root(root) {}
+
+        // StorageObject methods
+        virtual std::vector<std::string>    GetFileNames() override;
+        virtual std::shared_ptr<StreamBase> GetFile(std::string& fileName) override;
+        virtual void                        RemoveFile(std::string& fileName) override;
+        virtual std::shared_ptr<StreamBase> OpenFile(std::string& fileName, FileStream::Mode mode) override;
+        virtual void                        CommitChanges() override;
+
+    protected:
+        std::map<std::string, std::shared_ptr<StreamBase>> m_streams;
+        std::string m_root;
+
+    };//class ZipObject
+}

src/inc/Exceptions.hpp

@@ -9,7 +9,7 @@ namespace xPlat {
     class ExceptionBase : public std::exception
     {
     public:
-        enum Facility : uint32_t {
+        enum SubFacility : uint32_t {
             NONE = 0x0000,
             FILE = 0x1000,
             ZIP =  0x2000,
@@ -18,18 +18,19 @@ namespace xPlat {
         };
 
         ExceptionBase() {}
-        ExceptionBase(Facility facility) : facility(facility) {}
+        ExceptionBase(SubFacility subFacility) : subFacility(subFacility) {}
+        ExceptionBase(uint32_t headerOveride, SubFacility subFacility) : header(headerOveride), subFacility(subFacility) {}
 
         void SetLastError(uint32_t error)
         {
-            code = header + facility + (error & Facility::MAX);
+            code = header + subFacility + (error & SubFacility::MAX);
         }
 
         uint32_t Code() { return code; }
 
     protected:
-        Facility facility = Facility::NONE;
-        uint32_t header = 0x8BAD0000;   // facility 2989
+        SubFacility subFacility = SubFacility::NONE;
+        uint32_t    header = 0x8BAD0000;   // SubFacility 2989
         uint32_t    code   = 0xFFFFFFFF;   // by default, something very bad happened...
     };
 

src/inc/FileStream.hpp

@@ -12,7 +12,7 @@ namespace xPlat {
     {
     public:
         FileException(std::string message, uint32_t error = 0) :
-            ExceptionBase(ExceptionBase::Facility::FILE),
+            ExceptionBase(ExceptionBase::SubFacility::FILE),
             reason(message)
         {
             SetLastError(error);
@@ -58,9 +58,9 @@ namespace xPlat {
             offset = Ftell();
         }
 
-        virtual std::size_t Read(std::size_t size, const std::uint8_t* bytes) override
+        virtual std::uint64_t Read(std::uint64_t size, const std::uint8_t* bytes) override
         {
-            std::size_t bytesRead = std::fread(
+            std::uint64_t bytesRead = std::fread(
                 static_cast<void*>(const_cast<std::uint8_t*>(bytes)), 1, size, file
             );
             if (bytesRead < size && !Feof())

src/inc/StorageObject.hpp

@@ -0,0 +1,38 @@
+#pragma once
+
+#include "Exceptions.hpp"
+#include "StreamBase.hpp"
+#include "FileStream.hpp"
+
+#include <string>
+#include <vector>
+#include <memory>
+
+namespace xPlat {
+
+    // Interface over a namespace of collected file objects
+    class StorageObject
+    {
+    public:
+        virtual ~StorageObject() {}
+
+        // Obtains a vector of UTF-8 formatted string names contained in the storage object
+        virtual std::vector<std::string> GetFileNames() = 0;
+
+        // Obtains a pointer to a stream representing the file that exists in the storage object
+        virtual std::shared_ptr<StreamBase> GetFile(std::string& fileName) = 0;
+
+        // Remvoes a file by name from the storage object.  If the file does not exist, the operation is a no-op
+        virtual void RemoveFile(std::string& fileName) = 0;
+
+        // Opens a stream to a file by name in the storage object.  If the file does not exist and mode is read,
+        // or read + update, then nullptr is returned.  If the file is opened with write and it does not exist, 
+        // then the file is created and an empty stream to the file is handed back to the caller.
+        virtual std::shared_ptr<StreamBase> OpenFile(std::string& fileName, FileStream::Mode mode) = 0;
+
+        // Some storage objects may operate under cache semantics and therefore require an explicit commit.
+        // Clients should explicitly call CommitChanges after all write operations into the object are complete.
+        // An implementation of this interface MAY be a no-op.
+        virtual void CommitChanges() = 0;
+    };
+}

src/inc/StreamBase.hpp

@@ -14,19 +14,19 @@ namespace xPlat {
 
         // This way, derived classes only have to implement what they actually need, and everything else is not implemented.
         virtual void Write(std::size_t size, const std::uint8_t* bytes)       { throw NotImplementedException(); }
-        virtual std::size_t Read(std::size_t size, const std::uint8_t* bytes) { throw NotImplementedException(); }
+        virtual std::uint64_t Read(std::uint64_t size, const std::uint8_t* bytes) { throw NotImplementedException(); }
         virtual void Seek(std::uint64_t offset, Reference where)              { throw NotImplementedException(); }
         virtual int Ferror()                                                  { throw NotImplementedException(); }
         virtual bool Feof()                                                   { throw NotImplementedException(); }
         virtual std::uint64_t Ftell()                                         { throw NotImplementedException(); }
 
-        virtual void CopyTo(StreamBase& to)
+        virtual void CopyTo(StreamBase* to)
         {
             std::uint8_t buffer[1024];  // 1k at a time ought to be sufficient
             std::size_t bytes = Read(sizeof(buffer), buffer);
             while (bytes != 0)
             {
-                to.Write(bytes, buffer);
+                to->Write(bytes, buffer);
                 bytes = Read(sizeof(buffer), buffer);
             }
         }

src/inc/ZipFileStream.hpp

@@ -1,6 +1,7 @@
 
 #include "Exceptions.hpp"
 #include "StreamBase.hpp"
+#include "StreamBase.hpp"
 
 #include <string>
 
@@ -16,16 +17,25 @@ namespace xPlat {
             std::uint32_t offset,
             std::uint32_t compressedSize,
             std::uint32_t uncompressedSize,
-            bool isCompressed
+            bool isCompressed,
+            StreamBase* stream
         ) :
             m_fileName(std::move(fileName)),
             m_offset(offset),
             m_compressedSize(compressedSize),
             m_uncompressedSize(uncompressedSize),
-            m_isCompressed(isCompressed)
+            m_isCompressed(isCompressed),
+            m_stream(stream)
         {
         }
 
+        virtual void Write(std::size_t size, const std::uint8_t* bytes) override;
+        virtual std::uint64_t Read(std::uint64_t size, const std::uint8_t* bytes) override;
+        virtual void Seek(std::uint64_t offset, Reference where) override;
+        virtual int Ferror() override;
+        virtual bool Feof() override;
+        virtual std::uint64_t Ftell()  override;
+
     protected:
         std::string m_fileName;
 
@@ -36,5 +46,6 @@ namespace xPlat {
 
         bool m_isCompressed = false;
         std::uint64_t m_relativePosition = 0;
+        StreamBase* m_stream = nullptr;
     };
 }

src/inc/ZipObject.hpp

@@ -2,8 +2,7 @@
 
 #include "Exceptions.hpp"
 #include "StreamBase.hpp"
-#include "ObjectBase.hpp"
-#include "ZipFileStream.hpp"
+#include "StorageObject.hpp"
 
 #include <vector>
 #include <map>
@@ -26,7 +25,7 @@ namespace xPlat {
             InvalidLocalFileHeader              = 8,
         };
 
-        ZipException(std::string message, Error error) : reason(message), ExceptionBase(ExceptionBase::Facility::ZIP)
+        ZipException(std::string message, Error error) : reason(message), ExceptionBase(ExceptionBase::SubFacility::ZIP)
         {
             SetLastError(static_cast<std::uint32_t>(error));
         }
@@ -38,15 +37,20 @@ namespace xPlat {
     class LocalFileHeader;
 
     // This represents a raw stream over a.zip file.
-    class ZipObject
+    class ZipObject : public StorageObject
     {
     public:
         ZipObject(StreamBase* stream);
 
-        std::vector<std::string> GetFileNames();
+        // StorageObject methods
+        virtual std::vector<std::string>    GetFileNames() override;
+        virtual std::shared_ptr<StreamBase> GetFile(std::string& fileName) override;
+        virtual void                        RemoveFile(std::string& fileName) override;
+        virtual std::shared_ptr<StreamBase> OpenFile(std::string& fileName, FileStream::Mode mode) override;
+        virtual void                        CommitChanges() override;
 
     protected:
-        std::map<std::string, std::shared_ptr<ZipFileStream>>                m_streams;
+        std::map<std::string, std::shared_ptr<StreamBase>>                   m_streams;
         std::map<std::string, std::shared_ptr<CentralDirectoryFileHeader>>   m_centralDirectory;
 
         // TODO: change to uint64_t when adding full zip64 support

src/xPlatAppx/PAL/FileSystem/FTS/DirectoryObject.cpp

@@ -0,0 +1 @@
+// TODO: Implement FTS wrapper

src/xPlatAppx/PAL/FileSystem/Win32/DirectoryObject.cpp

@@ -0,0 +1,236 @@
+#include "Exceptions.hpp"
+#include "DirectoryObject.hpp"
+#include "FileStream.hpp"
+
+#include <memory>
+#include <iostream>
+#include <string>
+#include <sstream>
+#include <locale>
+#include <codecvt>
+
+// UNICODE MUST be defined before you include Windows.h if you want the non-ascii versions of APIs (and you do)
+#define UNICODE
+#include <windows.h>
+
+namespace xPlat {
+
+    class Win32Exception : public ExceptionBase
+    {
+    public:
+        Win32Exception(DWORD error) : ExceptionBase(0x8007, SubFacility::NONE)
+        {
+            SetLastError(static_cast<std::uint32_t>(error));
+        }
+    };
+
+    std::wstring utf8_to_utf16(std::string& utf8string)
+    {
+        /*
+        from: https://connect.microsoft.com/VisualStudio/feedback/details/1403302/unresolved-external-when-using-codecvt-utf8
+        Posted by Microsoft on 2/16/2016 at 11:49 AM
+        <snip>
+
+        A workaround is to replace 'char32_t' with 'unsigned int'. In VS2013, char32_t was a typedef of 'unsigned int'. In VS2015, char32_t is a distinct type of it's own. Switching your use of 'char32_t' to 'unsigned int' will get you the old behavior from earlier versions and won't trigger a missing export error.
+
+        There is also a similar error to this one with 'char16_t' that can be worked around using 'unsigned short'.
+        */
+        auto converted = std::wstring_convert<std::codecvt_utf8_utf16<unsigned short>, unsigned short>{}.from_bytes(utf8string.data());
+        std::wstring result(converted.begin(), converted.end());
+        return result;
+    }
+
+    std::string utf16_to_utf8(std::wstring& utf16string)
+    {
+        auto converted = std::wstring_convert<std::codecvt_utf8<wchar_t>>{}.to_bytes(utf16string.data());
+        std::string result(converted.begin(), converted.end());
+        return result;
+    }
+
+    enum class WalkOptions : std::uint16_t
+    {
+        Files = 1,          // Enumerate files within the specified directory
+        Directories = 2,    // Enumerate directories
+        Recursive = 4       // Enumerate recursively
+    };
+
+    inline constexpr WalkOptions operator &(WalkOptions a, WalkOptions b)
+    {
+        return static_cast<WalkOptions>(static_cast<uint16_t>(a) & static_cast<uint16_t>(b));
+    }
+
+    inline constexpr WalkOptions operator |(WalkOptions a, WalkOptions b)
+    {
+        return static_cast<WalkOptions>(static_cast<uint16_t>(a) | static_cast<uint16_t>(b));
+    }
+
+    template <WalkOptions options, class Lambda>
+    void WalkDirectory(std::string& root, Lambda& visitor)
+    {
+        static std::string dot(".");
+        static std::string dotdot("..");
+
+        std::wstring utf16Name = utf8_to_utf16(root);
+
+        WIN32_FIND_DATA findFileData = {};
+        std::unique_ptr<std::remove_pointer<HANDLE>::type, decltype(&::FindClose)> find(
+            FindFirstFile(reinterpret_cast<LPCWSTR>(utf16Name.c_str()), &findFileData),
+            &FindClose);
+
+        if (INVALID_HANDLE_VALUE == find.get())
+        {
+            DWORD lastError = GetLastError();
+            if (lastError == ERROR_FILE_NOT_FOUND)
+            {
+                return;
+            }
+            throw Win32Exception(lastError);
+        }
+
+        do
+        {
+            utf16Name = std::wstring(findFileData.cFileName);
+            auto utf8Name = utf16_to_utf8(utf16Name);
+
+            if (((options & WalkOptions::Directories) == WalkOptions::Directories) &&
+                (findFileData.dwFileAttributes & FILE_ATTRIBUTE_DIRECTORY)
+                )
+            {
+                std::string child = (root + "\\" + utf8Name);
+                if (!visitor(root, WalkOptions::Directories, std::move(utf8Name)))
+                {
+                    break;
+                }
+                if ((options & WalkOptions::Recursive) == WalkOptions::Recursive)
+                {
+                    WalkDirectory<options>(child, visitor);
+                }
+            }
+            else if ((options & WalkOptions::Files) == WalkOptions::Files)
+            {
+                if (dot != utf8Name && dotdot != utf8Name)
+                {
+                    if (!visitor(root, WalkOptions::Files, std::move(utf8Name)))
+                    {
+                        break;
+                    }
+                }
+            }
+        }
+        while (FindNextFile(find.get(), &findFileData));
+
+        DWORD lastError = GetLastError();
+        if ((lastError != ERROR_NO_MORE_FILES) && (lastError != ERROR_SUCCESS))
+        {
+            throw Win32Exception(lastError);
+        }
+    }
+
+    std::vector<std::string> DirectoryObject::GetFileNames()
+    {
+        std::vector<std::string> result;
+        WalkDirectory<WalkOptions::Files | WalkOptions::Directories | WalkOptions::Recursive>(m_root, [&](
+            std::string, 
+            WalkOptions option, 
+            std::string&& name)
+        {
+            if (option == WalkOptions::Files)
+            {
+                result.push_back(std::move(name));
+            }
+            return true;
+        });
+        return result;
+    }
+
+    std::shared_ptr<StreamBase> DirectoryObject::GetFile(std::string& fileName)
+    {
+        // first check cache
+        auto index = m_streams.find(fileName);
+        if (index != m_streams.cend())
+        {
+            return index->second;
+        }
+        // create stream and populate cache
+        std::string path = m_root + "\\" + fileName;
+        auto result = m_streams[fileName] = std::make_unique<FileStream>(std::move(fileName), FileStream::Mode::READ);
+
+        return result;
+    }
+
+    void DirectoryObject::RemoveFile(std::string& fileName)
+    {
+        throw NotImplementedException();
+    }
+
+    std::shared_ptr<StreamBase> DirectoryObject::OpenFile(std::string& fileName, FileStream::Mode mode)
+    {
+        static const std::string slash("\\");
+
+        std::vector<std::string> directories;
+        auto PopFirst = [&directories]()
+        {
+            auto result = directories.at(0);
+            std::vector<std::string>(directories.begin() + 1, directories.end()).swap(directories);
+            return result;
+        };
+        auto PopBack = [&directories]()
+        {
+            auto result = directories.at(directories.size() - 1);
+            directories.pop_back();
+            return result;
+        };
+
+        // Build a list of directory names to ensure exist
+        std::istringstream stream(fileName);
+        std::string directory;
+        while (getline(stream, directory, '/'))
+        {
+            directories.push_back(std::move(directory));
+        }
+        auto name = PopBack(); // remove the actual file name from the list of directories, but keep just the name
+
+        // Enforce that directory structure exists before creating file at specified location.
+        bool found = false;
+        std::string path = m_root;
+        while (directories.size() != 0)
+        {
+            WalkDirectory<WalkOptions::Directories>(path + slash + directories.front(), [&](
+                std::string,
+                WalkOptions option,
+                std::string&& name)
+            {
+                found = false;
+                if (directories.front() == name)
+                {
+                    found = true;
+                    path = path + slash + PopFirst();
+                    return false;
+                }
+
+                return true;
+            });
+
+            if (!found)
+            {
+                std::wstring utf16Name = utf8_to_utf16(path + slash + directories.front());
+                if (!CreateDirectory(utf16Name.c_str(), nullptr))
+                {
+                    throw Win32Exception(GetLastError());
+                }
+                path = path + slash + PopFirst();
+            }
+        }
+        name = path + slash + name;
+        auto result = m_streams[fileName] = std::make_unique<FileStream>(std::move(name), mode);
+        return result;
+    }
+
+    void DirectoryObject::CommitChanges()
+    {
+        m_streams.clear();
+    }
+}
+
+// Don't pollute other compilation units with any of our #defs...
+#undef UNICODE

src/xPlatAppx/ZipFileStream.cpp

@@ -0,0 +1,58 @@
+#include "ZipFileStream.hpp"
+#include "StreamBase.hpp"
+#include <limits>
+#include <algorithm>
+
+namespace xPlat {
+
+    void ZipFileStream::Write(std::size_t size, const std::uint8_t* bytes)
+    {
+        throw NotImplementedException();
+    }
+
+    std::uint64_t ZipFileStream::Read(std::uint64_t size, const std::uint8_t* bytes)
+    {
+        m_stream->Seek(m_offset + m_relativePosition, StreamBase::Reference::START);
+
+        std::uint64_t amountToRead = std::min(size, (m_compressedSize - m_relativePosition));
+        std::uint64_t bytesRead = m_stream->Read(amountToRead, bytes);
+        m_relativePosition += bytesRead;
+        return bytesRead;
+    }
+
+    void ZipFileStream::Seek(std::uint64_t offset, Reference where)
+    {
+        std::uint64_t newPos = 0;
+        switch (where)
+        {
+        case Reference::CURRENT:
+            newPos = m_offset + m_relativePosition + offset;
+            break;
+        case Reference::START:
+            newPos = m_offset + offset;
+            break;
+        case Reference::END:
+            newPos = m_offset + m_compressedSize + offset;
+            break;
+        }
+
+        m_stream->Seek(newPos, Reference::START);
+        m_relativePosition = m_stream->Ftell() - m_offset;
+    }
+
+    int ZipFileStream::Ferror()
+    {
+        return 0;
+    }
+
+    bool ZipFileStream::Feof()
+    {
+        return m_relativePosition >= m_compressedSize;
+    }
+
+    std::uint64_t ZipFileStream::Ftell()
+    {
+        return m_relativePosition;
+    }
+
+} /* xPlat */

src/xPlatAppx/ZipObject.cpp

@@ -2,6 +2,7 @@
 #include "StreamBase.hpp"
 #include "ObjectBase.hpp"
 #include "ZipObject.hpp"
+#include "ZipFileStream.hpp"
 
 #include <memory>
 #include <string>
@@ -754,6 +755,36 @@ namespace xPlat {
 
     };//class EndOfCentralDirectoryRecord
 
+    std::vector<std::string> ZipObject::GetFileNames()
+    {
+        std::vector<std::string> result;
+        std::for_each(m_streams.begin(), m_streams.end(), [&](auto it)
+        {
+            result.push_back(it.first);
+        });
+        return result;
+    }
+
+    std::shared_ptr<StreamBase> ZipObject::GetFile(std::string& fileName)
+    {
+        return m_streams[fileName];
+    }
+
+    void ZipObject::RemoveFile(std::string& fileName)
+    {
+        throw NotImplementedException();
+    }
+
+    std::shared_ptr<StreamBase> ZipObject::OpenFile(std::string& fileName, FileStream::Mode mode)
+    {
+        throw NotImplementedException();
+    }
+
+    void ZipObject::CommitChanges()
+    {
+        throw NotImplementedException();
+    }
+
     ZipObject::ZipObject(StreamBase* stream)
     {
         // Confirm that the file IS the correct format
@@ -801,23 +832,13 @@ namespace xPlat {
                 centralFileHeader.second->GetRelativeOffsetOfLocalHeader() + localFileHeader->Size(),
                 localFileHeader->GetCompressedSize(),
                 localFileHeader->GetUncompressedSize(),
-                localFileHeader->GetCompressionType() == CompressionType::Deflate
+                localFileHeader->GetCompressionType() == CompressionType::Deflate,
+                stream
                 );
 
             m_streams.insert(std::make_pair(
                 centralFileHeader.second->GetFileName(),
                 zipFileStream));
         }
-    }
-
-    std::vector<std::string> ZipObject::GetFileNames()
-    {
-        std::vector<std::string> result;
-        std::for_each(m_streams.begin(), m_streams.end(), [&](auto it)
-        {
-            result.push_back(it.first);
-        });
-        return result;
-    }
-
+    } // ZipObject::ZipObject
 } // namespace xPlat

src/xPlatAppx/xPlatAppx.cpp

@@ -3,6 +3,7 @@
 #include "StreamBase.hpp"
 #include "FileStream.hpp"
 #include "ZipObject.hpp"
+#include "DirectoryObject.hpp"
 
 #include <string>
 #include <memory>
@@ -49,21 +50,53 @@ unsigned int ResultOf(char* source, char* destination, Lambda lambda)
     return result;
 }
 
-XPLATAPPX_API unsigned int UnpackAppx(char* source, char* destination)
+XPLATAPPX_API unsigned int UnpackAppx(char* from, char* to)
 {
-    return ResultOf(source, destination, [&]() {
-        std::string appxFileName(source);
-        auto rawFile = std::make_unique<xPlat::FileStream>(
-            std::move(appxFileName),
-            xPlat::FileStream::Mode::READ);
+    return ResultOf(from, to, [&]() {
+        std::string source(from);
+        std::string target(to);
 
+        xPlat::DirectoryObject directory(std::move(target));
+
+        auto rawFile = std::make_unique<xPlat::FileStream>(std::move(source), xPlat::FileStream::Mode::READ);
+
+        {
             xPlat::ZipObject zip(rawFile.get());
+
+            auto fileNames = zip.GetFileNames();
+            for (auto fileName : fileNames)
+            {
+                auto sourceFile = zip.GetFile(fileName);
+                auto targetFile = directory.OpenFile(fileName, xPlat::FileStream::Mode::WRITE);
+
+                sourceFile->CopyTo(targetFile.get());
+            }
+        }
     });
 }
 
-XPLATAPPX_API unsigned int PackAppx  (char* source, char* destination)
+XPLATAPPX_API unsigned int PackAppx  (char* from, char* to)
 {
-    return ResultOf(source, destination, []() {
-        // TODO: implement here
+    return ResultOf(from, to, [&]() {
+        std::string source(from);
+        std::string target(to);
+
+        xPlat::DirectoryObject directory(std::move(source));
+
+        auto rawFile = std::make_unique<xPlat::FileStream>(std::move(target), xPlat::FileStream::Mode::WRITE);
+
+        {
+            xPlat::ZipObject zip(rawFile.get());
+
+            auto fileNames = directory.GetFileNames();
+            for (auto fileName : fileNames)
+            {
+                auto sourceFile = directory.GetFile(fileName);
+                auto targetFile = zip.OpenFile(fileName, xPlat::FileStream::Mode::WRITE);
+
+                sourceFile->CopyTo(targetFile.get());
+            }
+            zip.CommitChanges();
+        }
     });
 }