LZW數據壓縮

Question

我正在尋找可以壓縮和解壓縮Word文檔的C＃中的LZW壓縮算法。我在谷歌搜索它，但它沒有給我我需要的答案。任何人都可以幫助我獲得它的代碼，並讓我瞭解如何在我的項目中真正實現LZW。

Answer 1

有一個實現here。

LZW不關心它使用的文件類型。每個文件都被視爲一個字節塊。

Answer 2

一個C＃實現的LZW： http://code.google.com/p/sharp-lzw/

Answer 3

下面是我在我的項目中使用的LZW的實施：

namespace LZW 
{ 
    public class Program 
    { 
     public static void Main(string[] args) 
     { 
      List<int> compressed = Compress("string to be compressed"); 
      Console.WriteLine(string.Join(", ", compressed)); 
      string decompressed = Decompress(compressed); 
      Console.WriteLine(decompressed); 
     } 

     public static List<int> Compress(string uncompressed) 
     { 
      // build the dictionary 
      Dictionary<string, int> dictionary = new Dictionary<string, int>(); 
      for (int i = 0; i < 256; i++) 
       dictionary.Add(((char)i).ToString(), i); 

      string w = string.Empty; 
      List<int> compressed = new List<int>(); 

      foreach (char c in uncompressed) 
      { 
       string wc = w + c; 
       if (dictionary.ContainsKey(wc)) 
       { 
        w = wc; 
       } 
       else 
       { 
        // write w to output 
        compressed.Add(dictionary[w]); 
        // wc is a new sequence; add it to the dictionary 
        dictionary.Add(wc, dictionary.Count); 
        w = c.ToString(); 
       } 
      } 

      // write remaining output if necessary 
      if (!string.IsNullOrEmpty(w)) 
       compressed.Add(dictionary[w]); 

      return compressed; 
     } 

     public static string Decompress(List<int> compressed) 
     { 
      // build the dictionary 
      Dictionary<int, string> dictionary = new Dictionary<int, string>(); 
      for (int i = 0; i < 256; i++) 
       dictionary.Add(i, ((char)i).ToString()); 

      string w = dictionary[compressed[0]]; 
      compressed.RemoveAt(0); 
      StringBuilder decompressed = new StringBuilder(w); 

      foreach (int k in compressed) 
      { 
       string entry = null; 
       if (dictionary.ContainsKey(k)) 
        entry = dictionary[k]; 
       else if (k == dictionary.Count) 
        entry = w + w[0]; 

       decompressed.Append(entry); 

       // new sequence; add it to the dictionary 
       dictionary.Add(dictionary.Count, w + entry[0]); 

       w = entry; 
      } 

      return decompressed.ToString(); 
     } 
    } 
} 

Answer 4

對於任何絆腳石這個...我發現一個確切的C＃實現的the algorithm as described in the article on Mark Nelson's website在GitHub上，在這裏：

https://github.com/pevillarreal/LzwCompressor

每在聲音上，我進一步修改代碼以使用MemoryStream而不是FileStream，因爲我需要轉換字節數組，而不是保存的文件，但這種改變非常微不足道。