Bump version 1.1

README.md

@@ -1,5 +1,13 @@
 # .Net library for compressing URLs
 
+## Instalation
+
+You can install the NuGet package using this command on the package manager:
+	
+	Install-Package VAR.UrlCompressor 
+
+Alternativelly you can copy and reference the assembly resulting of the project VAR.UrlCompressor.
+
 ## Usage
 
 ### VAR.UrlCompressor
@@ -10,16 +18,28 @@ Add the resulting assembly as reference in your projects, and this line on code:
 Compress an URL with:
 
 	string compressedUrl = UrlCompressor.Compress("https:\\google.com");
+	// compressedUrl = "Hk30TGDxt8jOOW6"
 
 Decompress an URL with:
 
-	string decompressedUrl = UrlCompressor.Compress("xGncYbYfopHYpG0");
+	string decompressedUrl = UrlCompressor.Decompress("Hk30TGDxt8jOOW6");
+	// decompressedUrl = "Hk30TGDxt8jOOW6";
 	
+For extra compression use host conversions. For example:
+	
+	Dictionary<string, string> hostConversions = new Dictionary<string, string> {
+		{ "google", "G" }
+		{ "com", "C" }
+	}
+	string compressedUrl = UrlCompressor.Compress("https:\\google.com", );
+	// compressedUrl = "oMyuFVR41"
+
+
 ### UrlCompressor.Tests
 It is a simple console application, to test basic funcitionallity of the library.
 
 ## Building
-A Visual Studio 2015 and 2010 solutions are provided. Simply, click build on the IDE.
+A Visual Studio 2017 solution is provided. Simply, click build on the IDE.
 
 A .nuget package can be build using:
 	VAR.UrlCompressor\Build.NuGet.cmd

UrlCompressor.Tests/Program.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Collections.Generic;
 
 namespace UrlCompressor.Tests
 {
@@ -6,25 +7,31 @@ namespace UrlCompressor.Tests
     {
         static void Main(string[] args)
         {
-            TestUrl("http://google.com");
-            TestUrl("https://google.com");
-            TestUrl("http://facebook.com");
-            TestUrl("https://facebook.com");
-            TestUrl("https://twitter.com");
-            TestUrl("https://twitter.com/Kableado");
-            TestUrl("https://github.com/Kableado");
-            TestUrl("https://varstudio.net");
+            Dictionary<string, string> _hostConversions = new Dictionary<string, string> {
+                { "com", "C" },
+                { "net", "N" },
+                { "org", "O" },
+            };
+            
+            TestUrl("http://google.com", _hostConversions);
+            TestUrl("https://google.com", _hostConversions);
+            TestUrl("http://facebook.com", _hostConversions);
+            TestUrl("https://facebook.com", _hostConversions);
+            TestUrl("https://twitter.com", _hostConversions);
+            TestUrl("https://twitter.com/Kableado", _hostConversions);
+            TestUrl("https://github.com/Kableado", _hostConversions);
+            TestUrl("https://varstudio.net", _hostConversions);
 
             Console.Read();
         }
 
-        private static bool TestUrl(string url)
+        private static bool TestUrl(string url, Dictionary<string, string> _hostConversions)
         {
             Console.WriteLine("---------------------------------------------");
             Console.WriteLine("            Url: {0}", url);
-            string compressedUrl = VAR.UrlCompressor.UrlCompressor.Compress(url);
+            string compressedUrl = VAR.UrlCompressor.UrlCompressor.Compress(url, _hostConversions);
             Console.WriteLine("  CompressedUrl: {0}", compressedUrl);
-            string decompressedUrl = VAR.UrlCompressor.UrlCompressor.Decompress(compressedUrl);
+            string decompressedUrl = VAR.UrlCompressor.UrlCompressor.Decompress(compressedUrl, _hostConversions);
             Console.WriteLine("DecompressedUrl: {0}", decompressedUrl);
             if(url!= decompressedUrl)
             {

VAR.UrlCompressor/Base62.cs

@@ -53,6 +53,7 @@ namespace VAR.UrlCompressor
             for (int i = 0; i < base62.Length; i++)
             {
                 int charIdx = Base62CodingSpace.IndexOf(base62[i]);
+                if (charIdx == -1) { continue; }
                 if ((i + 1) == base62.Length)
                 {
                     // Last symbol
@@ -66,7 +67,7 @@ namespace VAR.UrlCompressor
                     bytes.WriteBit(bitPosition, 3 - pad, (charIdx & 0x04) > 0);
                     bytes.WriteBit(bitPosition, 4 - pad, (charIdx & 0x02) > 0);
                     bytes.WriteBit(bitPosition, 5 - pad, (charIdx & 0x01) > 0);
-
+                    bitPosition += (6 - pad);
                     break;
                 }
 
@@ -100,6 +101,8 @@ namespace VAR.UrlCompressor
                 }
             }
 
+
+            Array.Resize(ref bytes, (int)Math.Ceiling((double)bitPosition / 8));
             return bytes;
         }
     }

VAR.UrlCompressor/Properties/AssemblyInfo.cs

@@ -11,4 +11,4 @@ using System.Runtime.InteropServices;
 [assembly: AssemblyCulture("")]
 [assembly: ComVisible(false)]
 [assembly: Guid("016ae05d-12af-40c6-8d0c-064970004f0b")]
-[assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.1.*")]

VAR.UrlCompressor/Url.cs

@@ -0,0 +1,136 @@
+using System;
+
+namespace VAR.UrlCompressor
+{
+    class Url
+    {
+        public string Protocol { get; set; }
+        public string Host { get; set; }
+        public string Port { get; set; }
+        public string Path { get; set; }
+        
+        private Url() { }
+
+        private enum ParseStatus
+        {
+            ParsingProtocol,
+            ParsingHost,
+            ParsingPort,
+            ParsingPath,
+        };
+
+        private ParseStatus _status = ParseStatus.ParsingProtocol;
+        private int _i0 = 0;
+        private int _i = 0;
+
+        private void ResetParser()
+        {
+            _status = ParseStatus.ParsingProtocol;
+            _i0 = 0;
+            _i = 0;
+        }
+
+        private void ParseUrl(string url)
+        {
+            while (_i < url.Length)
+            {
+                switch (_status)
+                {
+                    case ParseStatus.ParsingProtocol:
+                        if (url[_i] == ':')
+                        {
+                            Protocol = url.Substring(_i0, _i - _i0);
+
+                            if (_i + 2 >= url.Length)
+                            {
+                                throw new Exception(string.Format("Unexpected end of URL, while parsing protocol. \"{0}\"", url));
+                            }
+                            if (url[_i + 1] != '/' || url[_i + 2] != '/')
+                            {
+                                throw new Exception(string.Format("Unexpected end of URL, while parsing protocol. \"{0}\"", url));
+                            }
+
+                            _status = ParseStatus.ParsingHost;
+                            _i0 = _i + 3;
+                            _i = _i0;
+                        }
+                        break;
+                    case ParseStatus.ParsingHost:
+                        if (char.IsLetterOrDigit(url[_i]) == false && url[_i] != '.')
+                        {
+                            Host = url.Substring(_i0, _i - _i0);
+                            _i0 = _i;
+
+                            if (url[_i] == ':')
+                            {
+                                _status = ParseStatus.ParsingPort;
+                            }
+                            else
+                            {
+                                _status = ParseStatus.ParsingPath;
+                            }
+                        }
+                        break;
+                    case ParseStatus.ParsingPort:
+                        if (char.IsDigit(url[_i]) == false)
+                        {
+                            Port = url.Substring(_i0, _i - _i0);
+                            _i0 = _i;
+                            _status = ParseStatus.ParsingPath;
+                        }
+                        break;
+                    case ParseStatus.ParsingPath:
+                        _i = url.Length - 1;
+                        break;
+                }
+                _i++;
+            }
+            switch (_status)
+            {
+                case ParseStatus.ParsingProtocol:
+                    Protocol = url.Substring(_i0, _i - _i0);
+                    break;
+                case ParseStatus.ParsingHost:
+                    Host = url.Substring(_i0, _i - _i0);
+                    break;
+                case ParseStatus.ParsingPort:
+                    Port = url.Substring(_i0, _i - _i0);
+                    break;
+                case ParseStatus.ParsingPath:
+                    Path = url.Substring(_i0, _i - _i0);
+                    break;
+            }
+        }
+
+
+        public static Url CreateFromString(string url)
+        {
+            var newUrl = new Url();
+            newUrl.ParseUrl(url);
+            return newUrl;
+        }
+
+        public static Url CreateFromShortString(string url)
+        {
+            var newUrl = new Url()
+            {
+                Protocol = url[0].ToString(),
+                _status = ParseStatus.ParsingHost,
+                _i = 1,
+                _i0 = 1,
+            };
+            newUrl.ParseUrl(url);
+            return newUrl;
+        }
+
+        public override string ToString()
+        {
+            return string.Format("{0}://{1}{2}{3}", Protocol, Host, Port, Path);
+        }
+
+        public string ToShortString()
+        {
+            return string.Format("{0}{1}{2}{3}", Protocol[0], Host, Port, Path);
+        }
+    }
+}

VAR.UrlCompressor/UrlCompressor.cs

@@ -1,4 +1,5 @@
-using System.Collections.Generic;
+using System;
+using System.Collections.Generic;
 using System.Text;
 
 namespace VAR.UrlCompressor
@@ -118,46 +119,120 @@ namespace VAR.UrlCompressor
             _huffmanTree = new HuffmanTree(frequencies);
         }
 
-        public static string Compress(string url)
+        private static void XorData(byte[] data, byte xorKey)
+        {
+            for (int i = 0; i < data.Length; i++)
+            {
+                data[i] = (byte)(data[i] ^ xorKey);
+            }
+        }
+
+        private static byte ChecksumCalculate(byte[] data)
+        {
+            byte checksum = 0;
+            foreach(byte b in data)
+            {
+                checksum = (byte)(checksum ^ b);
+            }
+            return checksum;
+        }
+
+        private static byte[] ChecksumAdd(byte[] data)
+        {
+            byte[] newData = new byte[data.Length + 1];
+            byte checksum = ChecksumCalculate(data);
+            XorData(data, checksum);
+            Array.Copy(data, 0, newData, 1, data.Length);
+            newData[0] = checksum;
+            return newData;
+        }
+
+        private static byte[] ChecksumCheck(byte[] data)
+        {
+            byte[] newData = new byte[data.Length - 1];
+            Array.Copy(data, 1, newData, 0, data.Length - 1);
+            byte oldChecksum = data[0];
+            XorData(newData, oldChecksum);
+            byte checksum = ChecksumCalculate(newData);
+            if (checksum != oldChecksum) { throw new Exception("Checksum mismatch."); }
+            return newData;
+        }
+
+        public static string Compress(string url, Dictionary<string, string> hostConversions = null)
         {
             InitHuffmanTree();
 
-            // Replace protocol indicator
-            if (url.StartsWith("https://") || url.StartsWith("HTTPS://"))
+            Url oUrl = Url.CreateFromString(url);
+            
+            // "Compress" protocol
+            if (oUrl.Protocol == "http" || oUrl.Protocol == null) { oUrl.Protocol = "#"; }
+            else if (oUrl.Protocol == "https") { oUrl.Protocol = "$"; }
+            else if (oUrl.Protocol == "ftp") { oUrl.Protocol = "F"; }
+            else { throw new Exception(string.Format("Unkown protocol \"{0}\"", oUrl.Protocol)); }
+
+            if (hostConversions != null)
             {
-                url = string.Format("${0}", url.Substring("https://".Length));
-            }
-            if (url.StartsWith("http://") || url.StartsWith("HTTP://"))
-            {
-                url = string.Format("#{0}", url.Substring("http://".Length));
+                // "Compress" hosts
+                string[] urlHostParts = oUrl.Host.Split('.');
+                for (int i = 0; i < urlHostParts.Length; i++)
+                {
+                    foreach (KeyValuePair<string, string> hostConversion in hostConversions)
+                    {
+                        if (urlHostParts[i] == hostConversion.Key)
+                        {
+                            urlHostParts[i] = hostConversion.Value;
+                            break;
+                        }
+                    }
+                }
+                oUrl.Host = string.Join(".", urlHostParts);
             }
 
+            url = oUrl.ToShortString();
+
+            // Reduce entropy
             byte[] urlBytes = Encoding.ASCII.GetBytes(url);
-
-            byte[] compressedUrlBytes = _huffmanTree.Encode(urlBytes);
-
-            return Base62.Encode(compressedUrlBytes);
+            urlBytes = _huffmanTree.Encode(urlBytes);
+            urlBytes = ChecksumAdd(urlBytes);
+            return Base62.Encode(urlBytes);
         }
 
-        public static string Decompress(string compressedUrl)
+        public static string Decompress(string compressedUrl, Dictionary<string, string> hostConversions = null)
         {
             InitHuffmanTree();
 
             byte[] urlBytes = Base62.Decode(compressedUrl);
+            urlBytes = ChecksumCheck(urlBytes);
+            urlBytes = _huffmanTree.Decode(urlBytes);
+            string url = Encoding.ASCII.GetString(urlBytes);
 
-            byte[] decompressedUrlBytes = _huffmanTree.Decode(urlBytes);
+            Url oUrl = Url.CreateFromShortString(url);
+            
+            // "Decompress" protocol
+            if (oUrl.Protocol == "#") { oUrl.Protocol = "http"; }
+            else if (oUrl.Protocol == "$") { oUrl.Protocol = "https"; }
+            else if (oUrl.Protocol == "F") { oUrl.Protocol = "ftp"; }
+            else { throw new Exception(string.Format("Unkown protocol \"{0}\"", oUrl.Protocol)); }
 
-            string url = Encoding.ASCII.GetString(decompressedUrlBytes);
-
-            // Restore protocol indicator
-            if (url.StartsWith("#"))
+            if (hostConversions != null)
             {
-                url = string.Format("http://{0}", url.Substring(1));
-            }
-            if (url.StartsWith("$"))
-            {
-                url = string.Format("https://{0}", url.Substring(1));
+                // "Decompress" hosts
+                string[] urlHostParts = oUrl.Host.Split('.');
+                for (int i = 0; i < urlHostParts.Length; i++)
+                {
+                    foreach (KeyValuePair<string, string> hostConversion in hostConversions)
+                    {
+                        if (urlHostParts[i] == hostConversion.Value)
+                        {
+                            urlHostParts[i] = hostConversion.Key;
+                            break;
+                        }
+                    }
+                }
+                oUrl.Host = string.Join(".", urlHostParts);
             }
+            
+            url = oUrl.ToString();
 
             return url;
         }

VAR.UrlCompressor/VAR.UrlCompressor.csproj

@@ -63,6 +63,7 @@
     <Compile Include="Huffman.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="UrlCompressor.cs" />
+    <Compile Include="Url.cs" />
   </ItemGroup>
   <ItemGroup>
     <None Include="Build.NuGet.cmd" />