added code for interface with 7-zip compression. and managing all the compression of files.

Saviour Backup System/Saviour Backup System.csproj

@@ -87,6 +87,7 @@
       <SpecificVersion>False</SpecificVersion>
       <HintPath>C:\Program Files (x86)\Microsoft SQL Server Compact Edition\v4.0\Desktop\System.Data.SqlServerCe.dll</HintPath>
     </Reference>
+    <Reference Include="System.IO.Compression.FileSystem" />
     <Reference Include="System.Xml.Linq" />
     <Reference Include="System.Data.DataSetExtensions" />
     <Reference Include="Microsoft.CSharp" />
@@ -124,6 +125,7 @@
     <Compile Include="backupViewer.Designer.cs">
       <DependentUpon>backupViewer.cs</DependentUpon>
     </Compile>
+    <Compile Include="compression.cs" />
     <Compile Include="currentTransfers.cs">
       <SubType>Form</SubType>
     </Compile>

Saviour Backup System/compression.cs

@@ -0,0 +1,91 @@
+using System;
+using System.Text;
+using System.Collections.Generic;
+using System.IO;
+using System.IO.Compression;
+using System.Threading;
+using Microsoft.Win32;
+using System.Windows.Forms;
+namespace Saviour_Backup_System
+{
+    class compression
+    {
+        private static List<Thread> threads = new List<Thread>();
+        private volatile static string Gdirectory;
+        private volatile static string Goutput;
+        private volatile static string GfileName;
+
+        public static void Compress(string directory, string outputFile, bool LZMA) {
+            GfileName = outputFile.Split('.')[0]; Gdirectory = directory; Goutput = outputFile; //store as globals
+            compressToZip();
+            if (!LZMA) { //We dont need to do LZMA, so just, dont!
+                File.Copy(Gdirectory + "\\" + GfileName + ".zip", Gdirectory.Replace("\\Temp", "") + GfileName + ".backup");
+            }
+            else if (has7Zip() && LZMA) {
+                DialogResult result = MessageBox.Show("7-Zip has been detected on your computer\nWould you like to use this instead?", "Use 7-Zip?", MessageBoxButtons.YesNo, MessageBoxIcon.Question);
+                if (result == DialogResult.Yes) {
+                    threads.Add(new Thread(new ThreadStart(compression7Zip)));
+                    threads[threads.Count].Start();
+                    return;
+                } else if (LZMA) {
+                    //Code to interface with 7z.exe goes here!
+                }
+            }
+            
+        }
+        private static void compression7Zip() { //need to write this!
+            string directory = Gdirectory;
+            string outputFile = Goutput;
+            return;
+        }
+
+        private static void compressToZip() {
+            ZipFile.CreateFromDirectory(Gdirectory, Gdirectory.Replace("\\Temp", "") + GfileName + ".zip");
+        }
+
+        private static void CompressFileLZMA(string inFile, string outFile)
+        {
+            SevenZip.Compression.LZMA.Encoder coder = new SevenZip.Compression.LZMA.Encoder();
+            FileStream input = new FileStream(inFile, FileMode.Open);
+            FileStream output = new FileStream(outFile, FileMode.Create);
+
+            // Write the encoder properties
+            coder.WriteCoderProperties(output);
+
+            // Write the decompressed file size.
+            output.Write(BitConverter.GetBytes(input.Length), 0, 8);
+
+            // Encode the file.
+            coder.Code(input, output, input.Length, -1, null);
+            output.Flush();
+            output.Close();
+        }
+
+        private static void DecompressFileLZMA(string inFile, string outFile)
+        {
+            SevenZip.Compression.LZMA.Decoder coder = new SevenZip.Compression.LZMA.Decoder();
+            FileStream input = new FileStream(inFile, FileMode.Open);
+            FileStream output = new FileStream(outFile, FileMode.Create);
+
+            // Read the decoder properties
+            byte[] properties = new byte[5];
+            input.Read(properties, 0, 5);
+
+            // Read in the decompress file size.
+            byte[] fileLengthBytes = new byte[8];
+            input.Read(fileLengthBytes, 0, 8);
+            long fileLength = BitConverter.ToInt64(fileLengthBytes, 0);
+
+            coder.SetDecoderProperties(properties);
+            coder.Code(input, output, input.Length, fileLength, null);
+            output.Flush();
+            output.Close();
+        }
+
+        private static bool has7Zip() {
+            string path = (string) Registry.GetValue("HKEY_LOCAL_MACHINE\\SOFTWARE\\7-Zip", "Path", "NULL");
+            if (path == "NULL") { return false;}
+            return File.Exists(path + "7z.exe");
+        }
+    }
+}