private static string _decompress(int length, int resetValue, GetNextValue getNextValue)
{
var dictionary = new Dictionary <int, string>();
int next, enlargeIn = 4, dictSize = 4, numBits = 3, i, resb;
var c = 0;
var result = new StringBuilder();
var data = new DataStruct()
{
Val = getNextValue(0), Position = resetValue, Index = 1
};
for (i = 0; i < 3; i++)
{
dictionary[i] = Convert.ToChar(i).ToString();
}
var bits = 0;
var maxpower = (int)Math.Pow(2, 2);
var power = 1;
while (power != maxpower)
{
resb = data.Val & data.Position;
data.Position >>= 1;
if (data.Position == 0)
{
data.Position = resetValue;
data.Val = getNextValue(data.Index++);
}
bits |= (resb > 0 ? 1 : 0) * power;
power <<= 1;
}
switch (next = bits)
{
case 0:
bits = 0;
maxpower = (int)Math.Pow(2, 8);
power = 1;
while (power != maxpower)
{
resb = data.Val & data.Position;
data.Position >>= 1;
if (data.Position == 0)
{
data.Position = resetValue;
data.Val = getNextValue(data.Index++);
}
bits |= (resb > 0 ? 1 : 0) * power;
power <<= 1;
}
c = Convert.ToInt32(F(bits));
break;
case 1:
bits = 0;
maxpower = (int)Math.Pow(2, 16);
power = 1;
while (power != maxpower)
{
resb = data.Val & data.Position;
data.Position >>= 1;
if (data.Position == 0)
{
data.Position = resetValue;
data.Val = getNextValue(data.Index++);
}
bits |= (resb > 0 ? 1 : 0) * power;
power <<= 1;
}
c = Convert.ToInt32(F(bits));
break;
case 2:
return("");
}
dictionary[3] = Convert.ToChar(c).ToString();
var w = Convert.ToChar(c).ToString();
result.Append(Convert.ToChar(c));
while (true)
{
if (data.Index > length)
{
return("");
}
bits = 0;
maxpower = (int)Math.Pow(2, numBits);
power = 1;
while (power != maxpower)
{
resb = data.Val & data.Position;
data.Position >>= 1;
if (data.Position == 0)
{
data.Position = resetValue;
data.Val = getNextValue(data.Index++);
}
bits |= (resb > 0 ? 1 : 0) * power;
power <<= 1;
}
switch (c = bits)
{
case 0:
bits = 0;
maxpower = (int)Math.Pow(2, 8);
power = 1;
while (power != maxpower)
{
resb = data.Val & data.Position;
data.Position >>= 1;
if (data.Position == 0)
{
data.Position = resetValue;
data.Val = getNextValue(data.Index++);
}
bits |= (resb > 0 ? 1 : 0) * power;
power <<= 1;
}
dictionary[dictSize++] = F(bits).ToString();
c = dictSize - 1;
enlargeIn--;
break;
case 1:
bits = 0;
maxpower = (int)Math.Pow(2, 16);
power = 1;
while (power != maxpower)
{
resb = data.Val & data.Position;
data.Position >>= 1;
if (data.Position == 0)
{
data.Position = resetValue;
data.Val = getNextValue(data.Index++);
}
bits |= (resb > 0 ? 1 : 0) * power;
power <<= 1;
}
dictionary[dictSize++] = F(bits).ToString();
c = dictSize - 1;
enlargeIn--;
break;
case 2:
return(result.ToString());
}
if (enlargeIn == 0)
{
enlargeIn = (int)Math.Pow(2, numBits);
numBits++;
}
var entry = "";
if (dictionary.ContainsKey(c))
{
entry = dictionary[c];
}
else
{
if (c == dictSize)
{
entry = w + w[0];
}
else
{
return(null);
}
}
result.Append(entry);
//Add w+entry[0] to the dictionary.
dictionary[dictSize++] = w + entry[0];
enlargeIn--;
w = entry;
if (enlargeIn != 0)
{
continue;
}
enlargeIn = (int)Math.Pow(2, numBits);
numBits++;
}
}
private static string _decompress(int length, int resetValue, GetNextValue getNextValue)
{
Dictionary<int, string> dictionary = new Dictionary<int, string>();
int next, enlargeIn = 4, dictSize = 4, numBits = 3, i, bits, resb, maxpower, power;
int c = 0;
string entry = "", w;
StringBuilder result = new StringBuilder();
var data = new dataStruct(){ val = getNextValue(0), position = resetValue, index = 1 };
for (i = 0; i < 3; i++)
{
dictionary[i] = Convert.ToChar(i).ToString();
}
bits = 0;
maxpower = (int)Math.Pow(2, 2);
power = 1;
while(power!=maxpower)
{
resb = data.val & data.position;
data.position >>= 1;
if(data.position == 0)
{
data.position = resetValue;
data.val = getNextValue(data.index++);
}
bits |= (resb > 0 ? 1 : 0) * power;
power <<= 1;
}
switch(next= bits)
{
case 0:
bits = 0;
maxpower = (int)Math.Pow(2, 8);
power = 1;
while (power != maxpower)
{
resb = data.val & data.position;
data.position >>= 1;
if (data.position == 0)
{
data.position = resetValue;
data.val = getNextValue(data.index++);
}
bits |= (resb > 0 ? 1 : 0) * power;
power <<= 1;
}
c = Convert.ToInt32(f(bits));
break;
case 1:
bits = 0;
maxpower = (int)Math.Pow(2, 16);
power = 1;
while(power!=maxpower)
{
resb = data.val & data.position;
data.position >>= 1;
if(data.position==0)
{
data.position = resetValue;
data.val = getNextValue(data.index++);
}
bits |= (resb > 0 ? 1 : 0) * power;
power <<= 1;
}
c = Convert.ToInt32(f(bits));
break;
case 2:
return "";
}
dictionary[3] = Convert.ToChar(c).ToString();
w = Convert.ToChar(c).ToString();
result.Append(Convert.ToChar(c));
while (true)
{
if (data.index > length)
{
return "";
}
bits = 0;
maxpower = (int)Math.Pow(2, numBits);
power = 1;
while (power != maxpower)
{
resb = data.val & data.position;
data.position >>= 1;
if (data.position == 0)
{
data.position = resetValue;
data.val = getNextValue(data.index++);
}
bits |= (resb > 0 ? 1 : 0) * power;
power <<= 1;
}
switch (c = bits)
{
case 0:
bits = 0;
maxpower = (int)Math.Pow(2, 8);
power = 1;
while(power!=maxpower)
{
resb = data.val & data.position;
data.position >>= 1;
if (data.position == 0)
{
data.position = resetValue;
data.val = getNextValue(data.index++);
}
bits |= (resb > 0 ? 1 : 0) * power;
power <<= 1;
}
dictionary[dictSize++] = f(bits).ToString();
c = dictSize - 1;
enlargeIn--;
break;
case 1:
bits = 0;
maxpower = (int)Math.Pow(2, 16);
power = 1;
while(power!=maxpower)
{
resb = data.val & data.position;
data.position >>= 1;
if (data.position == 0)
{
data.position = resetValue;
data.val = getNextValue(data.index++);
}
bits |= (resb > 0 ? 1 : 0) * power;
power <<= 1;
}
dictionary[dictSize++] = f(bits).ToString();
c = dictSize - 1;
enlargeIn--;
break;
case 2:
return result.ToString();
}
if(enlargeIn==0)
{
enlargeIn = (int)Math.Pow(2, numBits);
numBits++;
}
if(dictionary.ContainsKey(c))
{
entry = dictionary[c];
}
else
{
if(c==dictSize)
{
entry = w + w[0].ToString();
}
else
{
return null;
}
}
result.Append(entry);
//Add w+entry[0] to the dictionary.
dictionary[dictSize++] = w + entry[0].ToString();
enlargeIn--;
w = entry;
if(enlargeIn ==0)
{
enlargeIn = (int)Math.Pow(2, numBits);
numBits++;
}
}
}
