diff --git a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/pdom/tests/DBTest.java b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/pdom/tests/DBTest.java
index cb7f52904ee..9fcf58d4d31 100644
--- a/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/pdom/tests/DBTest.java
+++ b/core/org.eclipse.cdt.core.tests/parser/org/eclipse/cdt/internal/pdom/tests/DBTest.java
@@ -236,7 +236,7 @@ public class DBTest extends BaseTestCase {
 		doTrials(600, ShortString.MAX_LENGTH+1, ShortString.MAX_LENGTH*2, r, true);
 		doTrials(600, ShortString.MAX_LENGTH+1, ShortString.MAX_LENGTH*2, r, false);
 	}
-	
+		
 	private void doTrials(int n, int min, int max, Random r, boolean caseSensitive) throws CoreException {
 		long start = System.currentTimeMillis();
 		for(int i=0; i<n; i++) {
@@ -273,6 +273,16 @@ public class DBTest extends BaseTestCase {
 		IString aisc = db.newString(acs);
 		IString bisc = db.newString(bcs);
 		
+		assertEquals(a.hashCode(), aiss.hashCode());
+		assertEquals(a.hashCode(), aisc.hashCode());
+		assertEquals(b.hashCode(), biss.hashCode());
+		assertEquals(b.hashCode(), bisc.hashCode());
+		
+		assertEquals(aiss, a);
+		assertEquals(aisc, a);
+		assertEquals(biss, b);
+		assertEquals(bisc, b);
+		
 		assertSignEquals(expected, aiss.compare(bcs, caseSensitive));
 		assertSignEquals(expected, aiss.compare(biss, caseSensitive));
 		assertSignEquals(expected, aiss.compare(bisc, caseSensitive));
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/db/LongString.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/db/LongString.java
index 54de8293e1d..b68dedb7d3b 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/db/LongString.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/db/LongString.java
@@ -15,7 +15,7 @@ package org.eclipse.cdt.internal.core.pdom.db;
 
 import java.util.NoSuchElementException;
 
-import org.eclipse.cdt.internal.core.pdom.dom.PDOMNotImplementedError;
+import org.eclipse.cdt.core.CCorePlugin;
 import org.eclipse.core.runtime.CoreException;
 
 /**
@@ -28,7 +28,8 @@ import org.eclipse.core.runtime.CoreException;
 public class LongString implements IString {
 
 	private final Database db;
-	private final int record1;
+	private final int record;
+	private int hash;
 
 	// Additional fields of first record
 	private static final int LENGTH = 0; // must be first to match ShortString
@@ -43,9 +44,9 @@ public class LongString implements IString {
 	
 	private static final int NUM_CHARSN = (Database.MAX_SIZE - CHARSN) / 2;
 	
-	public LongString(Database db, int record1) {
+	public LongString(Database db, int record) {
 		this.db = db;
-		this.record1 = record1;
+		this.record = record;
 	}
 	
 	private interface IWriter {
@@ -81,7 +82,7 @@ public class LongString implements IString {
 	
 	public LongString(Database db, final String string) throws CoreException {
 		this.db = db;
-		this.record1 = createString(string.length(), new IWriter() {
+		this.record = createString(string.length(), new IWriter() {
 			public void writeChars(int start, int length, int p) throws CoreException {
 				for (int i = start; i < start + length; ++i) {
 					LongString.this.db.putChar(p, string.charAt(i));
@@ -93,7 +94,7 @@ public class LongString implements IString {
 	
 	public LongString(Database db, final char[] chars) throws CoreException {
 		this.db = db;
-		this.record1 = createString(chars.length, new IWriter() {
+		this.record = createString(chars.length, new IWriter() {
 			public void writeChars(int start, int length, int p) throws CoreException {
 				for (int i = start; i < start + length; ++i) {
 					LongString.this.db.putChar(p, chars[i]);
@@ -104,13 +105,13 @@ public class LongString implements IString {
 	}
 	
 	public int getRecord() {
-		return record1;
+		return record;
 	}
 
 	public void delete() throws CoreException {
-		int length = db.getInt(record1 + LENGTH) - NUM_CHARS1;
-		int nextRecord = db.getInt(record1 + NEXT1);
-		db.free(record1);
+		int length = db.getInt(record + LENGTH) - NUM_CHARS1;
+		int nextRecord = db.getInt(record + NEXT1);
+		db.free(record);
 		
 		// Middle records
 		while (length > NUM_CHARSN) {
@@ -125,11 +126,57 @@ public class LongString implements IString {
 	}
 	
 	public boolean equals(Object obj) {
-		throw new PDOMNotImplementedError();
+		if (obj == this)
+			return true;
+		try {
+			if (obj instanceof LongString) {
+				LongString lstr = (LongString)obj;
+				if (db == lstr.db && record == lstr.record)
+					return true;
+				return compare(lstr, true) == 0;
+			}
+			if (obj instanceof char[]) {
+				return compare((char[]) obj, true) == 0;
+			}
+			if (obj instanceof String) {
+				return compare((String) obj, true) == 0;
+			}
+		} catch (CoreException e) {
+			CCorePlugin.log(e);
+		}
+		return false;
 	}
 	
+	
+	private class HashCodeComputer implements IReader {
+		private int fHashcode= 0;
+
+		public int getHashcode() {
+			return fHashcode;
+		}
+
+		public void appendChar(char c) {
+			fHashcode = 31*fHashcode + c;
+		}
+	}
+	
+	/**
+	 * Compatible with {@link String#hashCode()}
+	 */
 	public int hashCode() {
-		return record1;
+		int h = hash;
+		if (h == 0) {
+			HashCodeComputer hcc;
+			try {
+				int length = db.getInt(record + LENGTH);
+				hcc = new HashCodeComputer();
+				readChars(length, hcc);
+				h= hcc.getHashcode();
+				hash = h;
+			} catch (CoreException e) {
+			}
+		}
+		return h;
 	}
 	
 	public int compare(IString string, boolean caseSensitive) throws CoreException {
@@ -246,13 +293,13 @@ public class LongString implements IString {
 	
 	private void readChars(int length, IReader reader) throws CoreException {
 		// First record
-		int p = record1 + CHARS1;
+		int p = record + CHARS1;
 		for (int i = 0; i < NUM_CHARS1; ++i) {
 			reader.appendChar(db.getChar(p));
 			p += 2;
 		}
 		length -= NUM_CHARS1;
-		int nextRecord = db.getInt(record1 + NEXT1);
+		int nextRecord = db.getInt(record + NEXT1);
 		
 		// Middle records
 		while (length > NUM_CHARSN) {
@@ -282,8 +329,8 @@ public class LongString implements IString {
 		int length;
 		
 		public CharIterator() throws CoreException {
-			p = record1 + CHARS1;
-			length =  db.getInt(record1 + LENGTH);
+			p = record + CHARS1;
+			length =  db.getInt(record + LENGTH);
 		}
 		
 		public char next() throws CoreException {
@@ -294,10 +341,10 @@ public class LongString implements IString {
 				throw new NoSuchElementException();
 			}
 			if(count == NUM_CHARS1) {
-				p = db.getInt(record1 + NEXT1) + CHARSN;
+				p = db.getInt(record + NEXT1) + CHARSN;
 			}
 			if(count > NUM_CHARS1 && ((count-NUM_CHARS1) % NUM_CHARSN)==0) {
-				p = db.getInt(record1 + NEXTN) + CHARSN;
+				p = db.getInt(p-(NUM_CHARSN*2)-4) + CHARSN;
 			}
 			return result;
 		}
@@ -308,7 +355,7 @@ public class LongString implements IString {
 	}
 	
 	public char[] getChars() throws CoreException {
-		int length = db.getInt(record1 + LENGTH);
+		int length = db.getInt(record + LENGTH);
 		final char[] chars = new char[length];
 		readChars(length, new IReader() {
 			int cp = 0;
@@ -320,7 +367,7 @@ public class LongString implements IString {
 	}
 
 	public String getString() throws CoreException {
-		int length = db.getInt(record1 + LENGTH);
+		int length = db.getInt(record + LENGTH);
 		final StringBuffer buffer = new StringBuffer(length);
 		readChars(length, new IReader() {
 			public void appendChar(char c) {
diff --git a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/db/ShortString.java b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/db/ShortString.java
index f632da91e3f..cb10ec93137 100644
--- a/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/db/ShortString.java
+++ b/core/org.eclipse.cdt.core/parser/org/eclipse/cdt/internal/core/pdom/db/ShortString.java
@@ -25,6 +25,7 @@ public class ShortString implements IString {
 	
 	private final Database db;
 	private final int record;
+	private int hash;
 	
 	private static final int LENGTH = 0;
 	private static final int CHARS = 4;
@@ -152,9 +153,24 @@ public class ShortString implements IString {
 		return false;
 	}
 	
+	/**
+	 * Compatible with {@link String#hashCode()}
+	 */
 	public int hashCode() {
-		// Custom hash code function to allow DBStrings in hashmaps.
-		return record;
+		int h = hash;
+		if (h == 0) {
+			char chars[];
+			try {
+				chars = getChars();
+				final int len = chars.length;
+				for (int i = 0; i < len; i++) {
+					h = 31*h + chars[i];
+				}
+			} catch (CoreException e) {
+			}
+			hash = h;
+		}
+		return h;
 	}
 	
 	public int compare(char[] other, boolean caseSensitive) throws CoreException {