This should be the API Arthur needs.

src/LedgerEntrySet.h

@@ -0,0 +1,54 @@
+#ifndef __LEDGERENTRYSET__
+#define __LEDGERENTRYSET__
+
+#include "SerializedLedger.h"
+
+enum LedgerEntryAction
+{
+	taaNONE,
+	taaCACHED,	// Unmodified.
+	taaMODIFY,	// Modifed, must have previously been taaCACHED.
+	taaDELETE,	// Delete, must have previously been taaDELETE or taaMODIFY.
+	taaCREATE,	// Newly created.
+}
+
+class LedgerEntrySetEntry
+{
+public:
+	SLE::pointer		mEntry;
+	LedgerEntryAction	mAction;
+	int					mSeq;
+
+};
+
+class LedgerEntrySet
+{
+protected:
+	boost::unordered_map<uint256, LedgerEntrySetEntry>	mEntries;
+	int mSeq;
+
+public:
+	LedgerEntrySet() : mSeq(0) { ; }
+
+	// set functions
+	LedgerEntrySet duplicate();			// Make a duplicate of this set
+	void setTo(LedgerEntrySet&);		// Set this set to have the same contents as another
+	void swapWith(LedgerEntrySet&);		// Swap the contents of two sets
+
+	// basic entry functions
+	SLE::pointer getEntry(const uint256& index, LedgerEntryAction&);
+	LedgerEntryAction hasEntry(const uint256& index) const;
+	void entryCache(SLE::pointer);		// Add this entry to the cache
+	void entryCreate(SLE::pointer);		// This entry will be created
+	void entryDelete(SLE::pointer);		// This entry will be deleted
+	void entryModify(SLE::pointer);		// This entry will be modified
+
+	// iterator functions
+	bool isEmpty() const;
+	boost::unordered_map<uint256, LedgerEntrySetEntry>::const_iterator begin() const;
+	boost::unordered_map<uint256, LedgerEntrySetEntry>::const_iterator end() const;
+	boost::unordered_map<uint256, LedgerEntrySetEntry>::iterator begin();
+	boost::unordered_map<uint256, LedgerEntrySetEntry>::iterator end();
+};
+
+#endif