pathfinding

2025-12-06 17:27:55 +00:00 · 2012-08-23 14:01:39 -07:00
parent cedb9d08fa
commit 27490e1f0b
6 changed files with 392 additions and 0 deletions
--- a/src/Pathfinder.cpp
+++ b/src/Pathfinder.cpp
@@ -0,0 +1,202 @@
+#include "Pathfinder.h"
+#include "Application.h"
+#include "RippleLines.h"
+#include "Log.h"
+#include <boost/foreach.hpp>
+
+/*
+JED: V IIII
+
+we just need to find a succession of the highest quality paths there until we find enough width
+
+Don't do branching within each path
+
+We have a list of paths we are working on but how do we compare the ones that are terminating in a different currency?
+
+Loops
+
+TODO: what is a good way to come up with multiple paths?
+	Maybe just change the sort criteria?
+	first a low cost one and then a fat short one?
+
+
+OrderDB:
+	getXNSOffers(); 
+	
+	// return list of all orderbooks that want XNS 
+	// return list of all orderbooks that want IssuerID
+	// return list of all orderbooks that want this issuerID and currencyID
+*/
+
+/*
+Test sending to XNS
+Test XNS to XNS
+Test offer in middle
+Test XNS to USD
+Test USD to EUR
+*/
+
+
+// we sort the options by:
+//    cost of path
+//    length of path
+//    width of path
+//    correct currency at the end
+
+
+
+bool sortPathOptions(PathOption::pointer first, PathOption::pointer second)
+{
+	if(first->mTotalCost<second->mTotalCost) return(true);
+	if(first->mTotalCost>second->mTotalCost) return(false);
+	
+	if(first->mCorrectCurrency && !second->mCorrectCurrency) return(true);
+	if(!first->mCorrectCurrency && second->mCorrectCurrency) return(false);
+
+	if(first->mPath.getElementCount()<second->mPath.getElementCount()) return(true);
+	if(first->mPath.getElementCount()>second->mPath.getElementCount()) return(false);
+
+	if(first->mMinWidth<second->mMinWidth) return true;
+	
+	return false;
+}
+
+PathOption::PathOption(uint160& srcAccount,uint160& srcCurrencyID,const uint160& dstCurrencyID)
+{
+	mCurrentAccount=srcAccount;
+	mCurrencyID=srcCurrencyID;
+	mCorrectCurrency=(srcCurrencyID==dstCurrencyID);
+	mQuality=0;
+	mMinWidth=STAmount(dstCurrencyID,99999,80);   // this will get lowered when we convert back to the correct currency
+}
+
+PathOption::PathOption(PathOption::pointer other)
+{
+	// TODO:
+}
+
+
+Pathfinder::Pathfinder(NewcoinAddress& srcAccountID, NewcoinAddress& dstAccountID, uint160& srcCurrencyID, STAmount dstAmount) : 
+	mSrcAccountID(srcAccountID.getAccountID()) , mDstAccountID(dstAccountID.getAccountID()), mSrcCurrencyID(srcCurrencyID) , mDstAmount(dstAmount), mOrderBook(theApp->getMasterLedger().getCurrentLedger())
+{
+	mLedger=theApp->getMasterLedger().getCurrentLedger();
+}
+
+bool Pathfinder::findPaths(int maxSearchSteps, int maxPay, STPathSet& retPathSet)
+{
+	if(mLedger)
+	{
+		PathOption::pointer head(new PathOption(mSrcAccountID,mSrcCurrencyID,mDstAmount.getCurrency()));
+		addOptions(head);
+
+		for(int n=0; n<maxSearchSteps; n++)
+		{
+			std::list<PathOption::pointer> tempPaths=mBuildingPaths;
+			mBuildingPaths.clear();
+			BOOST_FOREACH(PathOption::pointer path,tempPaths)
+			{
+				addOptions(path);
+			}
+			if(checkComplete(retPathSet)) return(true);
+		}
+		
+	}
+	
+	return(false);
+}
+
+bool Pathfinder::checkComplete(STPathSet& retPathSet)
+{
+	if(mCompletePaths.size())
+	{ // TODO: look through these and pick the most promising
+		int count=0;
+		BOOST_FOREACH(PathOption::pointer pathOption,mCompletePaths)
+		{
+			retPathSet.addPath(pathOption->mPath);
+			count++;
+			if(count>2) return(true);
+		}
+		return(true);
+	}
+	return(false);
+}
+
+
+// get all the options from this accountID
+//   if source is XNS
+//		every offer that wants XNS
+//   else 
+//		every ripple line that starts with the source currency 
+//		every offer that we can take that wants the source currency
+
+void Pathfinder::addOptions(PathOption::pointer tail)
+{
+	if(!tail->mCurrencyID)
+	{ // source XNS
+		BOOST_FOREACH(OrderBook::pointer book,mOrderBook.getXNSInBooks())
+		{
+			PathOption::pointer pathOption(new PathOption(tail));
+
+			STPathElement ele(uint160(), book->getCurrencyOut(), book->getIssuerOut());
+			pathOption->mPath.addElement(ele);
+
+			pathOption->mCurrentAccount=book->getIssuerOut();
+			pathOption->mCurrencyID=book->getCurrencyOut();
+			addPathOption(pathOption);
+		}
+	}else
+	{ // ripple
+		RippleLines rippleLines(tail->mCurrentAccount);
+		BOOST_FOREACH(RippleState::pointer line,rippleLines.getLines())
+		{
+			// TODO: make sure we can move in the correct direction
+			STAmount balance=line->getBalance();  
+			if(balance.getCurrency()==tail->mCurrencyID)
+			{  // we have a ripple line from the tail to somewhere else
+				PathOption::pointer pathOption(new PathOption(tail));
+
+				STPathElement ele(line->getAccountIDPeer().getAccountID(), uint160(),uint160());
+				pathOption->mPath.addElement(ele);
+
+
+				pathOption->mCurrentAccount=line->getAccountIDPeer().getAccountID();
+				addPathOption(pathOption);
+			}	
+		}
+
+		// every offer that wants the source currency
+		std::vector<OrderBook::pointer> books;
+		mOrderBook.getBooks(tail->mCurrentAccount, tail->mCurrencyID, books);
+
+		BOOST_FOREACH(OrderBook::pointer book,books)
+		{
+			PathOption::pointer pathOption(new PathOption(tail));
+
+			STPathElement ele(uint160(), book->getCurrencyOut(), book->getIssuerOut());
+			pathOption->mPath.addElement(ele);
+
+			pathOption->mCurrentAccount=book->getIssuerOut();
+			pathOption->mCurrencyID=book->getCurrencyOut();
+			addPathOption(pathOption);
+		}
+	}
+}
+
+void Pathfinder::addPathOption(PathOption::pointer pathOption)
+{
+	if(pathOption->mCurrencyID==mDstAmount.getCurrency()) 
+	{
+		pathOption->mCorrectCurrency=true;
+
+		if(pathOption->mCurrentAccount==mDstAccountID)
+		{ // this path is complete
+			mCompletePaths.push_back(pathOption);
+		}else mBuildingPaths.push_back(pathOption);
+	}else 
+	{
+		pathOption->mCorrectCurrency=false;
+		mBuildingPaths.push_back(pathOption);
+	}
+}
+
+