diff --git a/src/scratchpad/src/org/apache/poi/hdgf/HDGFLZW.java b/src/scratchpad/src/org/apache/poi/hdgf/HDGFLZW.java
index 91ae1a24e..2b1280837 100644
--- a/src/scratchpad/src/org/apache/poi/hdgf/HDGFLZW.java
+++ b/src/scratchpad/src/org/apache/poi/hdgf/HDGFLZW.java
@@ -40,7 +40,7 @@ public class HDGFLZW {
  *  the wrapping.
  * This is a convenience method
  */
-public byte fromInt(int b) {
+public static byte fromInt(int b) {
 	if(b < 128) return (byte)b;
 	return (byte)(b - 256);
 }
@@ -49,11 +49,21 @@ public byte fromInt(int b) {
  *  and 255 (i.e. handle the unwrapping).
  * This is a convenience method
  */
-public int fromByte(byte b) {
+public static int fromByte(byte b) {
 	if(b >= 0) return (int)b;
 	return (int)(b + 256);
 }
 
+/**
+ * Compress the given input stream, returning the array of bytes
+ *  of the compressed input
+ */
+public byte[] compress(InputStream src) throws IOException {
+	ByteArrayOutputStream res = new ByteArrayOutputStream();
+	compress(src,res);
+    return res.toByteArray();
+}
+
 /**
  * Decompresses the given input stream, returning the array of bytes
  *  of the decompressed input.
@@ -135,7 +145,7 @@ public void decode(InputStream src, OutputStream res) throws IOException {
 				//  length is the last 4 bits)
 				len = (dataIPt2 & 15) + 3;
 				pntr = (dataIPt2 & 240)*16 + dataIPt1;
-                
+
 				// If the pointer happens to be passed the end
 				//  of our buffer, then wrap around
 				if(pntr > 4078) {
@@ -158,4 +168,88 @@ public void decode(InputStream src, OutputStream res) throws IOException {
     }
 }
 
+/**
+ * Performs the Visio compatible streaming LZW compression.
+ * Works by:
+ * 1) ???
+ * 2) ???
+ * TODO - Finish
+ */
+public void compress(InputStream src, OutputStream res) throws IOException {
+	// We use 12 bit codes:
+	// * 0-255 are real bytes
+	// * 256-4095 are the substring codes
+	// Java handily initialises our buffer / dictionary
+	//  to all zeros
+	byte[] dict = new byte[4096];
+	// The next block of data to be written out, minus
+	//  its mask byte
+	byte[] buffer = new byte[16];
+	// And how long it is
+	// (Un-compressed codes are 1 byte each, compressed codes
+	//   are two)
+	int bufferLen = 0;
+	
+	// How far through the input and output streams we are
+	int posInp = 0;
+	int posOut = 0;
+	
+	// What the next mask byte to output will be
+	int nextMask = 0;
+	// And how many bits we've already set
+	int maskBitsSet = 0;
+	
+	// This is a byte as looked up in the dictionary
+	// It needs to be signed, as it'll get passed on to
+	//  the output stream
+	byte dataB;
+	// This is an unsigned byte read from the stream
+	// It needs to be unsigned, so that bit stuff works
+	int dataI;
+	
+	// Have we hit the end of the file yet?
+	boolean going = true;
+	
+	while( going ) {
+		dataI = src.read();
+		posInp++;
+		if(dataI == -1) { going = false; }
+		
+		// Decide if we're going to output uncompressed or compressed
+		//  for this byte
+		// (It takes 2 bytes to hold a compressed code, so it's only
+		//  worth doing for 3+ byte long sequences)
+		// TODO
+		
+		boolean compressThis = true;
+		if(compressThis) {
+			// Set the mask bit for us 
+			nextMask += (1<<maskBitsSet);
+			
+			// And add us to the buffer + dictionary
+			buffer[bufferLen] = fromInt(dataI);
+			bufferLen++;
+			dict[(posOut&4095)] = fromInt(dataI);
+			posOut++;
+		} else {
+			// ????
+		}
+		// Increment the mask bit count, we've done another code
+		maskBitsSet++;
+		
+		// If we've just done the 8th bit, or reached the end
+		//  of the stream, output our mask and data
+		if(maskBitsSet == 8 || !going) {
+			// Output
+			res.write(new byte[] { fromInt(nextMask) } );
+			res.write(buffer, 0, bufferLen);
+			
+			// Reset things
+			nextMask = 0;
+			maskBitsSet = 0;
+			bufferLen = 0;
+		}
+	}
+}
+
 }
\ No newline at end of file
diff --git a/src/scratchpad/testcases/org/apache/poi/hdgf/TestHDGFLZW.java b/src/scratchpad/testcases/org/apache/poi/hdgf/TestHDGFLZW.java
index 3e3986eee..f8f0f2555 100644
--- a/src/scratchpad/testcases/org/apache/poi/hdgf/TestHDGFLZW.java
+++ b/src/scratchpad/testcases/org/apache/poi/hdgf/TestHDGFLZW.java
@@ -22,10 +22,34 @@ import junit.framework.TestCase;
 
 public class TestHDGFLZW extends TestCase {
 	public static final byte[] testTrailerComp = new byte[] {
-		123, -60, 2, -21, -16, 1, 0, 0, -72, -13, -16, 78, -32, -5, 1, 
-		0, 3, -21, -16, 10, 5, 4, -21, -16, 21, 9, -21, -16, 103, -21, 
-		-16, 34, -36, -1, 52, 15, 70, 15, 120, 88, 15, -7, -2, -28, -9, 
-		-123, 21, 0, 44, -122, 1, -4, 104, 15, -24, -13, 40, -98, 32, 
+		123,      // *mask bit*
+		-60, 2, 
+		-21, -16, // 3 @ 4093
+		1, 0, 0, -72, 
+		-13, -16, // 3 @ 5
+		78,       // *mask bit*
+		-32, -5,  // 14 @ 4082 
+		1, 0, 3, 
+		-21, -16, // 3 @ 4093
+		10, 5,    // 8 @ 28
+		4, 
+		-21, -16, // 3 @ 4093
+		21,       // *mask bit* 
+		9, 
+		-21, -16, // 3 @ 4093 
+		103, -21, -16, 34, 
+		-36, -1,  // 18 @ 4078
+		52, 15,   // 18 @ 70 
+		70, 15,   // 18 @ 88 
+		120,      // *mask bit*
+		88, 15,   // 18 @ 106 
+		-7, -2,   // 17 @ 11 
+		-28, -9,  // 10 @ 4086
+		-123, 21, 0, 44, 
+		-122, 1,  // 4 @ 152 
+		-4,       // *mask bit* 
+		104, 15,  // 18 @ 122 
+		-24, -13, 40, -98, 32, 
 		78, 102, -67, -1, -2, -30, 64, 40, -67, -113, -73, 116, -98, 
 		-85, 2, 66, 123, 9, 109, -85, 2, -89, 14, -56, -69, -83, -79, 
 		-34, -3, 120, 110, 75, -9, -10, 20, -6, -25, -12, 22, -21, -16, 
@@ -81,6 +105,33 @@ public class TestHDGFLZW extends TestCase {
 		0, 0, 42, 1, 0, 0, 84, 0, 0, 0, 0, 0
 	};
 	
+	public void testFromToInt() throws Exception {
+		byte b255 = -1;
+		assertEquals(255, HDGFLZW.fromByte(b255));
+		assertEquals(-1, HDGFLZW.fromInt( HDGFLZW.fromByte(b255) ));
+		assertEquals(-1, HDGFLZW.fromInt( 255 ));
+		
+		byte b11 = 11;
+		assertEquals(11, HDGFLZW.fromByte(b11));
+		assertEquals(11, HDGFLZW.fromInt( HDGFLZW.fromByte(b11) ));
+		assertEquals(11, HDGFLZW.fromInt( 11 ));
+		
+		byte b0 = 0;
+		assertEquals(0, HDGFLZW.fromByte(b0));
+		assertEquals(0, HDGFLZW.fromInt( HDGFLZW.fromByte(b0) ));
+		assertEquals(0, HDGFLZW.fromInt( 0 ));
+		
+		byte b127 = 127;
+		assertEquals(127, HDGFLZW.fromByte(b127));
+		assertEquals(127, HDGFLZW.fromInt( HDGFLZW.fromByte(b127) ));
+		assertEquals(127, HDGFLZW.fromInt( 127 ));
+		
+		byte b128 = -128;
+		assertEquals(128, HDGFLZW.fromByte(b128));
+		assertEquals(-128, HDGFLZW.fromInt( HDGFLZW.fromByte(b128) ));
+		assertEquals(-128, HDGFLZW.fromInt( 128 ));
+	}
+	
 	public void testCounts() throws Exception {
 		assertEquals(339, testTrailerComp.length);
 		assertEquals(632, testTrailerDecomp.length);
@@ -91,11 +142,45 @@ public class TestHDGFLZW extends TestCase {
 		
 		// Check it's of the right size
 		assertEquals(632, dec.length);
+
+/*		
+		// Encode it again using our engine
+		byte[] comp = lzw.compress(new ByteArrayInputStream(testTrailerDecomp));
 		
-		// Now check it matches
+		// Check it's of the right size
+		assertEquals(339, comp.length);
+*/
+	}
+	
+	public void testDecompress() throws Exception {
+		assertEquals(339, testTrailerComp.length);
+		assertEquals(632, testTrailerDecomp.length);
+		
+		// Decode it using our engine
+		HDGFLZW lzw = new HDGFLZW();
+		byte[] dec = lzw.decode(new ByteArrayInputStream(testTrailerComp));
+		
+		// Now check it's the right data
+		assertEquals(632, dec.length);
 		for(int i=0; i<dec.length; i++) {
 			if(dec[i] != testTrailerDecomp[i]) 
 				System.err.println(i + "\t" + dec[i] + "\t" + testTrailerDecomp[i]);
 		}
 	}
+	
+	public void DISABLEDtestCompress() throws Exception {
+		assertEquals(339, testTrailerComp.length);
+		assertEquals(632, testTrailerDecomp.length);
+		
+		// Compress it using our engine
+		HDGFLZW lzw = new HDGFLZW();
+		byte[] comp = lzw.compress(new ByteArrayInputStream(testTrailerDecomp));
+		
+		// Now check it's the right data
+		assertEquals(339, comp.length);
+		for(int i=0; i<comp.length; i++) {
+			if(comp[i] != testTrailerComp[i]) 
+				System.err.println(i + "\t" + comp[i] + "\t" + testTrailerComp[i]);
+		}
+	}
 }