Add unpacktool

unpacktool/LZW.cpp

@@ -0,0 +1,159 @@
+#include "LZW.h"
+#include <stdlib.h>
+
+LZW *AllocLZW(int maxsymbols,int reservedsymbols)
+{
+	LZW *self=(LZW *)malloc(sizeof(LZW)+sizeof(LZWTreeNode)*(maxsymbols - 1));
+	if(!self) return 0;
+
+	self->maxsymbols=maxsymbols;
+	self->reservedsymbols=reservedsymbols;
+
+	self->buffer=NULL;
+	self->buffersize=0;
+
+	for(int i=0;i<256;i++)
+	{
+		self->nodes[i].chr=i;
+		self->nodes[i].parent=-1;
+	}
+
+	ClearLZWTable(self);
+
+	return self;
+}
+
+void FreeLZW(LZW *self)
+{
+	if(self)
+	{
+		free(self->buffer);
+		free(self);
+	}
+}
+
+void ClearLZWTable(LZW *self)
+{
+	self->numsymbols=256+self->reservedsymbols;
+	self->prevsymbol=-1;
+	self->symbolsize=9; // TODO: technically this depends on reservedsymbols
+}
+
+static uint8_t FindFirstByte(LZWTreeNode *nodes,int symbol)
+{
+	while(nodes[symbol].parent>=0) symbol=nodes[symbol].parent;
+	return nodes[symbol].chr;
+}
+
+int NextLZWSymbol(LZW *self,int symbol)
+{
+	if(self->prevsymbol<0)
+	{
+		if(symbol>=self->numsymbols) return LZWInvalidCodeError;
+		self->prevsymbol=symbol;
+
+		return LZWNoError;
+	}
+
+	int postfixbyte;
+	if(symbol<self->numsymbols) postfixbyte=FindFirstByte(self->nodes,symbol);
+	else if(symbol==self->numsymbols) postfixbyte=FindFirstByte(self->nodes,self->prevsymbol);
+	else return LZWInvalidCodeError;
+
+	int parent=self->prevsymbol;
+	self->prevsymbol=symbol;
+
+	if(!LZWSymbolListFull(self))
+	{
+		self->nodes[self->numsymbols].parent=parent;
+		self->nodes[self->numsymbols].chr=postfixbyte;
+		self->numsymbols++;
+
+		if(!LZWSymbolListFull(self))
+		if((self->numsymbols&self->numsymbols-1)==0) self->symbolsize++;
+
+		return LZWNoError;
+	}
+	else
+	{
+		return LZWTooManyCodesError;
+	}
+}
+
+int ReplaceLZWSymbol(LZW *self,int oldsymbol,int symbol)
+{
+	if(symbol>=self->numsymbols) return LZWInvalidCodeError;
+
+	self->nodes[oldsymbol].parent=self->prevsymbol;
+	self->nodes[oldsymbol].chr=FindFirstByte(self->nodes,symbol);
+
+	self->prevsymbol=symbol;
+
+	return LZWNoError;
+}
+
+int LZWOutputLength(LZW *self)
+{
+	int symbol=self->prevsymbol;
+	int n=0;
+
+	while(symbol>=0)
+	{
+		symbol=self->nodes[symbol].parent;
+		n++;
+	}
+
+	return n;
+}
+
+int LZWOutputToBuffer(LZW *self,uint8_t *buffer)
+{
+	int symbol=self->prevsymbol;
+	int n=LZWOutputLength(self);
+	buffer+=n;
+
+	while(symbol>=0)
+	{
+		*--buffer=self->nodes[symbol].chr;
+		symbol=self->nodes[symbol].parent;
+	}
+
+	return n;
+}
+
+int LZWReverseOutputToBuffer(LZW *self,uint8_t *buffer)
+{
+	int symbol=self->prevsymbol;
+	int n=0;
+
+	while(symbol>=0)
+	{
+		*buffer++=self->nodes[symbol].chr;
+		symbol=self->nodes[symbol].parent;
+		n++;
+	}
+
+	return n;
+}
+
+int LZWOutputToInternalBuffer(LZW *self)
+{
+	int symbol=self->prevsymbol;
+	int n=LZWOutputLength(self);
+
+	if(n>self->buffersize)
+	{
+		free(self->buffer);
+		self->buffersize+=1024;
+		self->buffer=static_cast<uint8_t*>(malloc(self->buffersize));
+	}
+
+	uint8_t *buffer=self->buffer+n;
+	while(symbol>=0)
+	{
+		*--buffer=self->nodes[symbol].chr;
+		symbol=self->nodes[symbol].parent;
+	}
+
+	return n;
+}