work on filters

pom.xml

@@ -51,6 +51,11 @@
     </distributionManagement>
 
     <dependencies>
+		<dependency>
+		    <groupId>commons-lang</groupId>
+		    <artifactId>commons-lang</artifactId>
+		    <version>2.6</version>
+		</dependency>
         <dependency>
             <groupId>org.junit.jupiter</groupId>
             <artifactId>junit-jupiter-engine</artifactId>
@@ -134,17 +139,6 @@
                     <autoReleaseAfterClose>false</autoReleaseAfterClose>
                 </configuration>
             </plugin>
-            <plugin>
-                <groupId>org.apache.maven.plugins</groupId>
-                <artifactId>maven-javadoc-plugin</artifactId>
-                <executions>
-                    <execution>
-                        <goals>
-                            <goal>jar</goal>
-                        </goals>
-                    </execution>
-                </executions>
-            </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-source-plugin</artifactId>

src/main/java/gr/aueb/compression/gorilla/DecompressorPmcMr.java

@@ -0,0 +1,49 @@
+package gr.aueb.compression.gorilla;
+
+import java.util.List;
+
+import gr.aueb.compression.gorilla.PmcMR.Constant;
+
+public class DecompressorPmcMr {
+
+	private List<Constant> constants;
+    private float storedVal = 0f;
+    private boolean endOfStream = false;
+    private int currentElement = 0;
+    private int currentTimestampOffset = 0;
+
+    public DecompressorPmcMr(List<Constant> constants) {
+    	this.constants = constants;
+    }
+
+    /**
+     * Returns the next pair in the time series, if available.
+     *
+     * @return Pair if there's next value, null if series is done.
+     */
+    public Float readValue() {
+        next();
+        if(endOfStream) {
+            return null;
+        }
+        return storedVal;
+    }
+
+    private void next() {
+    	Constant constant = constants.get(currentElement);
+    	if (constant.getFinalTimestamp() >= (constant.getInitialTimestamp() + currentTimestampOffset)) {
+    		storedVal = constant.getValue();
+    		currentTimestampOffset++;
+    	} else {
+    		currentElement++;
+    		if (currentElement < constants.size()) {
+    			constant = constants.get(currentElement);
+    			storedVal = constant.getValue();
+    			currentTimestampOffset = 1;
+    		} else {
+    			endOfStream = true;
+    		}
+    	}
+	}
+
+}

src/main/java/gr/aueb/compression/gorilla/DecompressorSwingFilter.java

@@ -0,0 +1,50 @@
+package gr.aueb.compression.gorilla;
+
+import java.util.List;
+
+import gr.aueb.compression.gorilla.PmcMR.Constant;
+import gr.aueb.compression.gorilla.SwingFilter.SwingSegment;
+
+public class DecompressorSwingFilter {
+
+	private List<SwingSegment> swingSegments;
+    private float storedVal = 0f;
+    private boolean endOfStream = false;
+    private int currentElement = 0;
+    private int currentTimestampOffset = 0;
+
+    public DecompressorSwingFilter(List<SwingSegment> swingSegments) {
+    	this.swingSegments = swingSegments;
+    }
+
+    /**
+     * Returns the next pair in the time series, if available.
+     *
+     * @return Pair if there's next value, null if series is done.
+     */
+    public Float readValue() {
+        next();
+        if(endOfStream) {
+            return null;
+        }
+        return storedVal;
+    }
+
+    private void next() {
+    	SwingSegment swingSegment = swingSegments.get(currentElement);
+    	if (swingSegment.getFinalTimestamp() >= (swingSegment.getInitialTimestamp() + currentTimestampOffset)) {
+    		storedVal = swingSegment.getLine().get(swingSegment.getInitialTimestamp() + currentTimestampOffset);
+    		currentTimestampOffset++;
+    	} else {
+    		currentElement++;
+    		if (currentElement < swingSegments.size()) {
+    			swingSegment = swingSegments.get(currentElement);
+    			storedVal = swingSegment.getLine().get(swingSegment.getInitialTimestamp());
+    			currentTimestampOffset = 1;
+    		} else {
+    			endOfStream = true;
+    		}
+    	}
+	}
+
+}

src/main/java/gr/aueb/compression/gorilla/LinearFunction.java

@@ -0,0 +1,32 @@
+/* Copyright 2018 The ModelarDB Contributors
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package gr.aueb.compression.gorilla;
+
+public class LinearFunction {
+
+    /** Constructors **/
+    public LinearFunction(long ts, float vs, long te, float ve) {
+        this.a = (ve - vs) / (te - ts);
+        this.b = vs - a * ts;
+    }
+
+    /** Public Methods **/
+    public float get(long ts) {
+        return this.a * ts + this.b;
+    }
+
+    /** Instance Variables **/
+    public final float a, b;
+}

src/main/java/gr/aueb/compression/gorilla/LossyCompressor32.java

@@ -78,6 +78,15 @@ public void close() {
     }
 
     private void compressValue(int value) {
+    	// if values is within error wrt the previous value, use the previous value
+    	if (Math.abs(Float.intBitsToFloat(value) - Float.intBitsToFloat(storedVal)) < Math.pow(2, this.logOfError)) {
+    		// Write 0
+        	cases[0] += 1;
+            out.skipBit();
+            size += 1;
+            return;
+    	}
+
         // TODO Fix already compiled into a big method
     	int integerDigits = (value << 1 >>> 24) - 127;
     	int space = 23 + this.logOfError - integerDigits;

src/main/java/gr/aueb/compression/gorilla/PmcMR.java

@@ -0,0 +1,87 @@
+package gr.aueb.compression.gorilla;
+
+import java.util.ArrayList;
+import java.util.Collection;
+import java.util.List;
+
+public class PmcMR {
+
+
+	public List<Constant> filter(Collection<Point> points, float epsilon) {
+
+		List<Constant> constants = new ArrayList<>();
+		Constant currentConstant = null;
+
+		float max = Float.MIN_VALUE;
+		float min = Float.MAX_VALUE;
+
+		for (Point point : points) {
+
+			if (point.getValue() > max) {
+				max = point.getValue();
+			}
+			if (point.getValue() < min) {
+				min = point.getValue();
+			}
+
+			if (max - min <= epsilon && currentConstant != null) {
+				currentConstant.setFinalTimestamp(point.getTimestamp());
+				currentConstant.setValue(max - ((max - min) / 2));
+			} else {
+				if (currentConstant != null) {
+					constants.add(currentConstant);	
+				}
+				max = point.getValue();
+				min = point.getValue();
+				currentConstant = new Constant();
+				currentConstant.setInitialTimestamp(point.getTimestamp());
+				currentConstant.setFinalTimestamp(point.getTimestamp());
+				currentConstant.setValue(point.getValue());
+			}
+
+		}
+		if (currentConstant != null) {
+			constants.add(currentConstant);	
+		}
+
+		return constants;
+	}
+
+	public class Constant {
+
+		private long initialTimestamp;
+		private long finalTimestamp;
+		private float value;
+
+		public void setFinalTimestamp(long finalTimestamp) {
+			this.finalTimestamp = finalTimestamp;
+		}
+
+		public void setInitialTimestamp(long initialTimestamp) {
+			this.initialTimestamp = initialTimestamp;
+		}
+
+		public void setValue(float value) {
+			this.value = value;
+		}
+
+		public long getFinalTimestamp() {
+			return finalTimestamp;
+		}
+
+		public long getInitialTimestamp() {
+			return initialTimestamp;
+		}
+
+		public float getValue() {
+			return value;
+		}
+
+		@Override
+		public String toString() {
+			return String.format("%d-%d: %f", getInitialTimestamp(), getFinalTimestamp(), getValue());
+		}
+
+	}
+
+}

src/main/java/gr/aueb/compression/gorilla/Point.java

@@ -0,0 +1,21 @@
+package gr.aueb.compression.gorilla;
+
+public class Point {
+
+	private final long timestamp;
+	private final float value;
+
+	public Point(long timestamp, float value) {
+		this.timestamp = timestamp;
+		this.value = value;
+	}
+
+	public long getTimestamp() {
+		return timestamp;
+	}
+
+	public float getValue() {
+		return value;
+	}
+
+}