merge dasher which has been introduced in BRANCH first (wtf?) into HEAD

1 files changed, 309 insertions, 0 deletions

diff --git a/inputmethods/dasher/PPMLanguageModel.cpp b/inputmethods/dasher/PPMLanguageModel.cpp
new file mode 100644
index 0000000..b725a2b
--- a/dev/null
+++ b/inputmethods/dasher/PPMLanguageModel.cpp
@@ -0,0 +1,309 @@
+// PPMLanguageModel.h
+//
+/////////////////////////////////////////////////////////////////////////////
+//
+// Copyright (c) 1999-2002 David Ward
+//
+/////////////////////////////////////////////////////////////////////////////
+
+#include <math.h>
+#include "PPMLanguageModel.h"
+
+using namespace Dasher;
+using namespace std;
+
+// static TCHAR debug[256];
+typedef unsigned long ulong;
+
+////////////////////////////////////////////////////////////////////////
+/// PPMnode definitions 
+////////////////////////////////////////////////////////////////////////
+
+CPPMLanguageModel::CPPMnode *CPPMLanguageModel::CPPMnode::find_symbol(int sym)
+// see if symbol is a child of node
+{
+	//  printf("finding symbol %d at node %d\n",sym,node->id);
+	CPPMnode *found=child;
+	while (found) {
+		if (found->symbol==sym)
+			return found;
+		found=found->next;
+	}
+	return 0;
+}
+
+
+CPPMLanguageModel::CPPMnode * CPPMLanguageModel::CPPMnode::add_symbol_to_node(int sym,int *update)
+{
+	CPPMnode *born,*search;
+	search=find_symbol(sym);
+	if (!search) {
+		born = new CPPMnode(sym);
+		born->next=child;
+		child=born;
+		//   node->count=1;
+		return born;		
+	} else {
+		if (*update) {   // perform update exclusions
+			search->count++;
+			*update=0;
+		}
+		return search;
+	}
+	
+}
+
+
+/////////////////////////////////////////////////////////////////////
+// CPPMLanguageModel defs
+/////////////////////////////////////////////////////////////////////
+
+CPPMLanguageModel::CPPMLanguageModel(CAlphabet *_alphabet,int _normalization)
+	: CLanguageModel(_alphabet,_normalization)
+{
+	root=new CPPMnode(-1);
+	m_rootcontext=new CPPMContext(root,0);
+}
+
+
+CPPMLanguageModel::~CPPMLanguageModel()
+{
+	delete root;
+}
+
+
+bool CPPMLanguageModel::GetProbs(CContext *context,vector<unsigned int> &probs,double addprob)
+	// get the probability distribution at the context
+{
+	// seems like we have to have this hack for VC++
+	CPPMContext *ppmcontext=static_cast<CPPMContext *> (context);
+	
+	
+	int modelchars=GetNumberModelChars();
+	int norm=CLanguageModel::normalization();
+	probs.resize(modelchars);
+	CPPMnode *temp,*s; 
+	int loop,total;
+	int sym; 
+	ulong spent=0; 
+	ulong size_of_slice;
+	bool *exclusions=new bool [modelchars];
+	ulong uniform=modelchars;
+	ulong tospend=norm-uniform;
+	temp=ppmcontext->head;
+	for (loop=0; loop <modelchars; loop++) {   /* set up the exclusions array */
+		probs[loop]=0;
+		exclusions[loop]=0;
+	}
+	while (temp!=0) {
+		//	Usprintf(debug,TEXT("tospend %u\n"),tospend);
+		//	DebugOutput(TEXT("round\n"));
+		total=0;
+		s=temp->child;
+		while (s) {
+			sym=s->symbol; 
+			if (!exclusions[s->symbol])
+				total=total+s->count;
+			s=s->next;
+		}
+		if (total) {
+			//	Usprintf(debug,TEXT"escape %u\n"),tospend*
+			size_of_slice=tospend;
+			s=temp->child;
+			while (s) {
+				if (!exclusions[s->symbol]) {
+					exclusions[s->symbol]=1;
+					ulong p=size_of_slice*(2*s->count-1)/2/ulong(total);
+					probs[s->symbol]+=p;
+					tospend-=p;		
+				}
+				//				Usprintf(debug,TEXT("sym %u counts %d p %u tospend %u \n"),sym,s->count,p,tospend);	 
+				//				DebugOutput(debug);
+				s=s->next;
+			}
+		}
+		temp = temp->vine;
+	}
+	//	Usprintf(debug,TEXT("Norm %u tospend %u\n"),Norm,tospend);
+	//	DebugOutput(debug);
+	
+	size_of_slice=tospend;
+	int symbolsleft=0;
+	for (sym=1;sym<modelchars;sym++)
+		if (!probs[sym])
+			symbolsleft++;
+		for (sym=1;sym<modelchars;sym++) 
+			if (!probs[sym]) {
+				ulong p=size_of_slice/symbolsleft;
+				probs[sym]+=p;
+				tospend-=p;
+			}
+			
+			// distribute what's left evenly	
+			tospend+=uniform;
+			for (sym=1;sym<modelchars;sym++) {
+				ulong p=tospend/(modelchars-sym);
+				probs[sym]+=p;
+				tospend-=p;
+			}
+			//	Usprintf(debug,TEXT("finaltospend %u\n"),tospend);
+			//	DebugOutput(debug);
+			
+			// free(exclusions); // !!!
+			// !!! NB by IAM: p577 Stroustrup 3rd Edition: "Allocating an object using new and deleting it using free() is asking for trouble"
+			delete[] exclusions;
+			return true;
+}
+
+
+void CPPMLanguageModel::AddSymbol(CPPMLanguageModel::CPPMContext &context,int symbol)
+	// add symbol to the context
+	// creates new nodes, updates counts
+	// and leaves 'context' at the new context
+{
+	// sanity check
+	if (symbol==0 || symbol>=GetNumberModelChars())
+		return;
+	
+	CPPMnode *vineptr,*temp;
+	int updatecnt=1;
+	
+	temp=context.head->vine;
+	context.head=context.head->add_symbol_to_node(symbol,&updatecnt);
+	vineptr=context.head;
+	context.order++;
+	
+	while (temp!=0) {
+		vineptr->vine=temp->add_symbol_to_node(symbol,&updatecnt);    
+		vineptr=vineptr->vine;
+		temp=temp->vine;
+	}
+	vineptr->vine=root;
+	if (context.order>MAX_ORDER){
+		context.head=context.head->vine;
+		context.order--;
+	}
+}
+
+
+// update context with symbol 'Symbol'
+void CPPMLanguageModel::EnterSymbol(CContext* Context, modelchar Symbol)
+{
+	CPPMLanguageModel::CPPMContext& context = * static_cast<CPPMContext *> (Context);
+	
+	CPPMnode *find;
+	CPPMnode *temp=context.head;
+	
+	while (context.head) {
+		find =context.head->find_symbol(Symbol);
+		if (find) {
+			context.order++;
+			context.head=find;
+			//	Usprintf(debug,TEXT("found context %x order %d\n"),head,order);
+			//	DebugOutput(debug);
+			return;
+		}
+		context.order--;
+		context.head=context.head->vine;
+	}
+	
+	if (context.head==0) {
+		context.head=root;
+		context.order=0;
+	}
+	
+}
+
+
+void CPPMLanguageModel::LearnSymbol(CContext* Context, modelchar Symbol)
+{
+	CPPMLanguageModel::CPPMContext& context = * static_cast<CPPMContext *> (Context);
+	AddSymbol(context, Symbol);
+}
+
+
+void CPPMLanguageModel::dumpSymbol(int symbol)
+{
+	if ((symbol <= 32) || (symbol >= 127))
+		printf( "<%d>", symbol );
+	else
+		printf( "%c", symbol );
+}
+
+
+void CPPMLanguageModel::dumpString( char *str, int pos, int len )
+	// Dump the string STR starting at position POS
+{
+	char cc;
+	int p;
+	for (p = pos; p<pos+len; p++) {
+		cc = str [p];
+		if ((cc <= 31) || (cc >= 127))
+			printf( "<%d>", cc );
+		else
+			printf( "%c", cc );
+	}
+}
+
+
+void CPPMLanguageModel::dumpTrie( CPPMLanguageModel::CPPMnode *t, int d )
+	// diagnostic display of the PPM trie from node t and deeper
+{
+//TODO
+/*
+	dchar debug[256];
+	int sym;
+	CPPMnode *s;
+	Usprintf( debug,TEXT("%5d %7x "), d, t );
+	//TODO: Uncomment this when headers sort out
+	//DebugOutput(debug);
+	if (t < 0) // pointer to input
+		printf( "                     <" );
+	else {
+		Usprintf(debug,TEXT( " %3d %5d %7x  %7x  %7x    <"), t->symbol,t->count, t->vine, t->child, t->next );
+		//TODO: Uncomment this when headers sort out
+		//DebugOutput(debug);
+	}
+	
+	dumpString( dumpTrieStr, 0, d );
+	Usprintf( debug,TEXT(">\n") );
+	//TODO: Uncomment this when headers sort out
+	//DebugOutput(debug);
+	if (t != 0) {
+		s = t->child;
+		while (s != 0) {
+			sym =s->symbol;
+			
+			dumpTrieStr [d] = sym;
+			dumpTrie( s, d+1 );
+			s = s->next;
+		}
+	}
+*/
+}
+
+
+void CPPMLanguageModel::dump()
+	// diagnostic display of the whole PPM trie
+{
+// TODO:
+/*
+	dchar debug[256];
+	Usprintf(debug,TEXT(  "Dump of Trie : \n" ));
+	//TODO: Uncomment this when headers sort out
+	//DebugOutput(debug);
+	Usprintf(debug,TEXT(   "---------------\n" ));
+	//TODO: Uncomment this when headers sort out
+	//DebugOutput(debug);
+	Usprintf( debug,TEXT(  "depth node     symbol count  vine   child      next   context\n") );
+	//TODO: Uncomment this when headers sort out
+	//DebugOutput(debug);
+	dumpTrie( root, 0 );
+	Usprintf( debug,TEXT(  "---------------\n" ));
+	//TODO: Uncomment this when headers sort out
+	//DebugOutput(debug);
+	Usprintf(debug,TEXT( "\n" ));
+	//TODO: Uncomment this when headers sort out
+	//DebugOutput(debug);
+*/
+}