private static string _compress(string uncompressed, int bitsPerChar, GetCharFromInt getCharFromInt)
{
if (uncompressed == null)
{
return("");
}
int i, value, ii, context_enlargeIn = 2, context_dictSize = 3, context_numBits = 2, context_data_val = 0, context_data_position = 0;
Dictionary <string, bool> context_dictionaryToCreate = new Dictionary <string, bool>();
Dictionary <string, int> context_dictionary = new Dictionary <string, int>();
StringBuilder context_data = new StringBuilder();
string context_c = "";
string context_wc = "", context_w = "";
for (ii = 0; ii < uncompressed.Length; ii++)
{
context_c = uncompressed[ii].ToString();
if (!context_dictionary.ContainsKey(context_c))
{
context_dictionary[context_c] = context_dictSize++;
context_dictionaryToCreate[context_c] = true;
}
context_wc = context_w + context_c;
if (context_dictionary.ContainsKey(context_wc))
{
context_w = context_wc;
}
else
{
if (context_dictionaryToCreate.ContainsKey(context_w))
{
if (Convert.ToInt32(context_w[0]) < 256)
{
for (i = 0; i < context_numBits; i++)
{
context_data_val = (context_data_val << 1);
if (context_data_position == bitsPerChar - 1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
}
value = Convert.ToInt32(context_w[0]);
for (i = 0; i < 8; i++)
{
context_data_val = (context_data_val << 1) | (value & 1);
if (context_data_position == bitsPerChar - 1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = value >> 1;
}
}
else
{
value = 1;
for (i = 0; i < context_numBits; i++)
{
context_data_val = (context_data_val << 1) | value;
if (context_data_position == bitsPerChar - 1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = 0;
}
value = Convert.ToInt32(context_w[0]);
for (i = 0; i < 16; i++)
{
context_data_val = (context_data_val << 1) | (value & 1);
if (context_data_position == bitsPerChar - 1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = value >> 1;
}
}
context_enlargeIn--;
if (context_enlargeIn == 0)
{
context_enlargeIn = (int)Math.Pow(2, context_numBits);
context_numBits++;
}
context_dictionaryToCreate.Remove(context_w);
}
else
{
value = context_dictionary[context_w];
for (i = 0; i < context_numBits; i++)
{
context_data_val = (context_data_val << 1) | (value & 1);
if (context_data_position == bitsPerChar - 1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = value >> 1;
}
}
context_enlargeIn--;
if (context_enlargeIn == 0)
{
context_enlargeIn = (int)Math.Pow(2, context_numBits);
context_numBits++;
}
//Add wc to the dictionary
context_dictionary[context_wc] = context_dictSize++;
context_w = context_c;
}
}
//Output the code for w
if (context_w != "")
{
if (context_dictionaryToCreate.ContainsKey(context_w))
{
if (Convert.ToInt32(context_w[0]) < 256)
{
for (i = 0; i < context_numBits; i++)
{
context_data_val = (context_data_val << 1);
if (context_data_position == bitsPerChar - 1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
}
value = Convert.ToInt32(context_w[0]);
for (i = 0; i < 8; i++)
{
context_data_val = (context_data_val << 1) | (value & 1);
if (context_data_position == bitsPerChar - 1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = value >> 1;
}
}
else
{
value = 1;
for (i = 0; i < context_numBits; i++)
{
context_data_val = (context_data_val << 1) | value;
if (context_data_position == bitsPerChar - 1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = 0;
}
value = Convert.ToInt32(context_w[0]);
for (i = 0; i < 16; i++)
{
context_data_val = (context_data_val << 1) | (value & 1);
if (context_data_position == bitsPerChar - 1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = value >> 1;
}
}
context_enlargeIn--;
if (context_enlargeIn == 0)
{
context_enlargeIn = (int)Math.Pow(2, context_numBits);
context_numBits++;
}
context_dictionaryToCreate.Remove(context_w);
}
else
{
value = context_dictionary[context_w];
for (i = 0; i < context_numBits; i++)
{
context_data_val = (context_data_val << 1) | (value & 1);
if (context_data_position == bitsPerChar - 1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = value >> 1;
}
}
context_enlargeIn--;
if (context_enlargeIn == 0)
{
context_enlargeIn = (int)Math.Pow(2, context_numBits);
context_numBits++;
}
}
//Mark the end of the stream
value = 2;
for (i = 0; i < context_numBits; i++)
{
context_data_val = (context_data_val << 1) | (value & 1);
if (context_data_position == bitsPerChar - 1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = value >> 1;
}
//Flush the last char
while (true)
{
context_data_val = (context_data_val << 1);
if (context_data_position == bitsPerChar - 1)
{
context_data.Append(getCharFromInt(context_data_val));
break;
}
else
{
context_data_position++;
}
}
return(context_data.ToString());
}
private static string _compress(string uncompressed, int bitsPerChar, GetCharFromInt getCharFromInt)
{
if (uncompressed == null) return "";
int i, value, ii, context_enlargeIn = 2, context_dictSize = 3, context_numBits = 2, context_data_val = 0, context_data_position = 0;
Dictionary<string, bool> context_dictionaryToCreate = new Dictionary<string, bool>();
Dictionary<string, int> context_dictionary = new Dictionary<string, int>();
StringBuilder context_data = new StringBuilder();
string context_c ="";
string context_wc = "", context_w = "";
for(ii=0;ii<uncompressed.Length;ii++)
{
context_c = uncompressed[ii].ToString();
if(!context_dictionary.ContainsKey(context_c))
{
context_dictionary[context_c] = context_dictSize++;
context_dictionaryToCreate[context_c] = true;
}
context_wc = context_w + context_c;
if(context_dictionary.ContainsKey(context_wc))
{
context_w = context_wc;
}
else
{
if(context_dictionaryToCreate.ContainsKey(context_w))
{
if(Convert.ToInt32(context_w[0])<256)
{
for(i=0;i<context_numBits;i++)
{
context_data_val = (context_data_val << 1);
if(context_data_position==bitsPerChar-1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
}
value = Convert.ToInt32(context_w[0]);
for(i=0;i<8;i++)
{
context_data_val = (context_data_val << 1) | (value & 1);
if(context_data_position==bitsPerChar-1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = value >> 1;
}
}
else
{
value = 1;
for(i=0;i<context_numBits;i++)
{
context_data_val = (context_data_val << 1) | value;
if(context_data_position==bitsPerChar-1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = 0;
}
value = Convert.ToInt32(context_w[0]);
for(i=0;i<16;i++)
{
context_data_val = (context_data_val << 1) | (value & 1);
if(context_data_position==bitsPerChar-1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = value >> 1;
}
}
context_enlargeIn--;
if(context_enlargeIn==0)
{
context_enlargeIn = (int)Math.Pow(2, context_numBits);
context_numBits++;
}
context_dictionaryToCreate.Remove(context_w);
}
else
{
value = context_dictionary[context_w];
for(i=0;i<context_numBits;i++)
{
context_data_val = (context_data_val << 1) | (value & 1);
if(context_data_position==bitsPerChar-1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = value >> 1;
}
}
context_enlargeIn--;
if(context_enlargeIn==0)
{
context_enlargeIn = (int)Math.Pow(2, context_numBits);
context_numBits++;
}
//Add wc to the dictionary
context_dictionary[context_wc] = context_dictSize++;
context_w = context_c;
}
}
//Output the code for w
if(context_w!="")
{
if(context_dictionaryToCreate.ContainsKey(context_w))
{
if(Convert.ToInt32(context_w[0])<256)
{
for(i=0;i<context_numBits;i++)
{
context_data_val = (context_data_val << 1);
if(context_data_position==bitsPerChar-1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
}
value = Convert.ToInt32(context_w[0]);
for(i=0;i<8;i++)
{
context_data_val = (context_data_val << 1) | (value & 1);
if(context_data_position==bitsPerChar-1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = value >> 1;
}
}
else
{
value = 1;
for(i=0;i<context_numBits;i++)
{
context_data_val = (context_data_val << 1) | value;
if(context_data_position==bitsPerChar-1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = 0;
}
value = Convert.ToInt32(context_w[0]);
for(i=0;i<16;i++)
{
context_data_val = (context_data_val << 1) | (value & 1);
if(context_data_position==bitsPerChar-1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = value >> 1;
}
}
context_enlargeIn--;
if(context_enlargeIn==0)
{
context_enlargeIn = (int)Math.Pow(2, context_numBits);
context_numBits++;
}
context_dictionaryToCreate.Remove(context_w);
}
else
{
value = context_dictionary[context_w];
for(i=0;i<context_numBits;i++)
{
context_data_val = (context_data_val << 1) | (value & 1);
if(context_data_position==bitsPerChar-1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = value >> 1;
}
}
context_enlargeIn--;
if(context_enlargeIn==0)
{
context_enlargeIn = (int)Math.Pow(2, context_numBits);
context_numBits++;
}
}
//Mark the end of the stream
value = 2;
for(i=0;i<context_numBits;i++)
{
context_data_val = (context_data_val << 1) | (value & 1);
if(context_data_position==bitsPerChar-1)
{
context_data_position = 0;
context_data.Append(getCharFromInt(context_data_val));
context_data_val = 0;
}
else
{
context_data_position++;
}
value = value >> 1;
}
//Flush the last char
while(true)
{
context_data_val = (context_data_val << 1);
if (context_data_position == bitsPerChar - 1)
{
context_data.Append(getCharFromInt(context_data_val));
break;
}
else context_data_position++;
}
return context_data.ToString();
}
