diff --git a/components/net/sf/briar/transport/FrameWindow.java b/components/net/sf/briar/transport/FrameWindow.java
index dcb1d75a9e81b78df78113940e8ab8c61355b2aa..85e162b1f1cc90c909dfe91ead44e7b933606953 100644
--- a/components/net/sf/briar/transport/FrameWindow.java
+++ b/components/net/sf/briar/transport/FrameWindow.java
@@ -2,21 +2,15 @@ package net.sf.briar.transport;
interface FrameWindow {
+ /** Returns true if the given number is too high to fit in the window. */
+ boolean isTooHigh(long frameNumber);
+
/** Returns true if the given number is in the window. */
boolean contains(long frameNumber);
/**
- * Advances the window so it is centred on the given number, unless the
- * centre is already greater than the number. Returns false if the window
- * is unmodifiable.
- */
- boolean advance(long frameNumber);
-
- /**
- * Removes the given number from the window and, if the number is greater
- * than or equal to the window's centre, advances the centre to one greater
- * than the given number. Returns false if the given number is not in the
- * window or the window is unmodifiable.
+ * Removes the given number from the window and advances the window.
+ * Returns false if the given number is not in the window.
*/
boolean remove(long frameNumber);
}
diff --git a/components/net/sf/briar/transport/FrameWindowImpl.java b/components/net/sf/briar/transport/FrameWindowImpl.java
index 3348ce73f4fe18a16d86fb9ab3922638b1f16fb8..ddf3e71cf65793dca4c97199dba7bcbfc09afd9f 100644
--- a/components/net/sf/briar/transport/FrameWindowImpl.java
+++ b/components/net/sf/briar/transport/FrameWindowImpl.java
@@ -5,59 +5,57 @@ import static net.sf.briar.util.ByteUtils.MAX_32_BIT_UNSIGNED;
import java.util.Collection;
import java.util.HashSet;
-import java.util.Iterator;
class FrameWindowImpl implements FrameWindow {
private final Collection<Long> window;
- private long centre;
+ private long base;
FrameWindowImpl() {
window = new HashSet<Long>();
- for(long l = 0; l < FRAME_WINDOW_SIZE / 2; l++) window.add(l);
- centre = 0;
+ fill(0, FRAME_WINDOW_SIZE);
+ base = 0;
}
- public boolean contains(long frameNumber) {
+ public boolean isTooHigh(long frameNumber) {
if(frameNumber < 0 || frameNumber > MAX_32_BIT_UNSIGNED)
throw new IllegalArgumentException();
- return window.contains(frameNumber);
+ return frameNumber >= base + FRAME_WINDOW_SIZE;
}
- public boolean advance(long frameNumber) {
+ public boolean contains(long frameNumber) {
if(frameNumber < 0 || frameNumber > MAX_32_BIT_UNSIGNED)
throw new IllegalArgumentException();
- if(frameNumber <= centre) return true;
- // Remove values that have passed out of the window
- long newBottom = getBottom(frameNumber);
- Iterator<Long> it = window.iterator();
- while(it.hasNext()) if(it.next() < newBottom) it.remove();
- // Add values that have passed into the window
- long fillFrom = Math.max(newBottom, getTop(centre) + 1);
- long newTop = getTop(frameNumber);
- for(long l = fillFrom; l <= newTop; l++) window.add(l);
- centre = frameNumber;
- return true;
+ return window.contains(frameNumber);
}
public boolean remove(long frameNumber) {
if(frameNumber < 0 || frameNumber > MAX_32_BIT_UNSIGNED)
throw new IllegalArgumentException();
if(!window.remove(frameNumber)) return false;
- if(frameNumber >= centre && frameNumber < MAX_32_BIT_UNSIGNED)
- advance(frameNumber + 1);
+ if(frameNumber == base) {
+ // Find the new base
+ if(window.isEmpty()) {
+ base += FRAME_WINDOW_SIZE;
+ fill(base, base + FRAME_WINDOW_SIZE);
+ } else {
+ for(long l = base; l < base + FRAME_WINDOW_SIZE; l++) {
+ if(window.contains(l)) {
+ fill(base + FRAME_WINDOW_SIZE, l + FRAME_WINDOW_SIZE);
+ base = l;
+ break;
+ }
+ }
+ }
+ }
return true;
}
- // Returns the lowest value contained in a window with the given centre
- private static long getBottom(long centre) {
- return Math.max(0, centre - FRAME_WINDOW_SIZE / 2);
- }
-
- // Returns the highest value contained in a window with the given centre
- private static long getTop(long centre) {
- return Math.min(MAX_32_BIT_UNSIGNED,
- centre + FRAME_WINDOW_SIZE / 2 - 1);
+ private void fill(long from, long to) {
+ for(long l = from; l < to; l++) {
+ if(l <= MAX_32_BIT_UNSIGNED) window.add(l);
+ else return;
+ }
}
}
diff --git a/components/net/sf/briar/transport/NullFrameWindow.java b/components/net/sf/briar/transport/NullFrameWindow.java
index c8560de86161b2ecca76a325d2b00255d6bff3c0..c56a78a37dea818d2c0f01109d39d52c378f4b3f 100644
--- a/components/net/sf/briar/transport/NullFrameWindow.java
+++ b/components/net/sf/briar/transport/NullFrameWindow.java
@@ -1,20 +1,28 @@
package net.sf.briar.transport;
+import static net.sf.briar.util.ByteUtils.MAX_32_BIT_UNSIGNED;
+
class NullFrameWindow implements FrameWindow {
- private long centre = 0L;
+ private long base = 0L;
- public boolean contains(long frameNumber) {
- return frameNumber == centre;
+ public boolean isTooHigh(long frameNumber) {
+ if(frameNumber < 0 || frameNumber > MAX_32_BIT_UNSIGNED)
+ throw new IllegalArgumentException();
+ return frameNumber != base;
}
- public boolean advance(long frameNumber) {
- return frameNumber == centre;
+ public boolean contains(long frameNumber) {
+ if(frameNumber < 0 || frameNumber > MAX_32_BIT_UNSIGNED)
+ throw new IllegalArgumentException();
+ return frameNumber == base;
}
public boolean remove(long frameNumber) {
- if(frameNumber != centre) return false;
- centre++;
+ if(frameNumber < 0 || frameNumber > MAX_32_BIT_UNSIGNED)
+ throw new IllegalArgumentException();
+ if(frameNumber != base) return false;
+ base++;
return true;
}
}
diff --git a/components/net/sf/briar/transport/NullIncomingReliabilityLayer.java b/components/net/sf/briar/transport/NullIncomingReliabilityLayer.java
index 3ecd84502c6bd9081f2767c1bfa7a774144903b5..25ddb59d24846c50ac99adc6c5d7b93b07c5dfcc 100644
--- a/components/net/sf/briar/transport/NullIncomingReliabilityLayer.java
+++ b/components/net/sf/briar/transport/NullIncomingReliabilityLayer.java
@@ -15,8 +15,7 @@ class NullIncomingReliabilityLayer implements IncomingReliabilityLayer {
public boolean readFrame(Frame f) throws IOException, InvalidDataException {
if(!in.readFrame(f, window)) return false;
long frameNumber = HeaderEncoder.getFrameNumber(f.getBuffer());
- if(!window.remove(frameNumber) && window.advance(frameNumber))
- throw new RuntimeException();
+ if(!window.remove(frameNumber)) throw new IllegalStateException();
return true;
}
}
diff --git a/test/net/sf/briar/transport/FrameWindowImplTest.java b/test/net/sf/briar/transport/FrameWindowImplTest.java
index 1cc08245701af5501d48d0df6d78d4db22cb7df9..fc8913befca114f27139d541c02111513e5a8eb5 100644
--- a/test/net/sf/briar/transport/FrameWindowImplTest.java
+++ b/test/net/sf/briar/transport/FrameWindowImplTest.java
@@ -1,8 +1,7 @@
package net.sf.briar.transport;
-import net.sf.briar.BriarTestCase;
import static net.sf.briar.api.transport.TransportConstants.FRAME_WINDOW_SIZE;
-import static net.sf.briar.util.ByteUtils.MAX_32_BIT_UNSIGNED;
+import net.sf.briar.BriarTestCase;
import org.junit.Test;
@@ -13,77 +12,71 @@ public class FrameWindowImplTest extends BriarTestCase {
FrameWindow w = new FrameWindowImpl();
for(int i = 0; i < 100; i++) {
assertTrue(w.contains(i));
- w.remove(i);
+ assertTrue(w.remove(i));
assertFalse(w.contains(i));
}
+ for(int i = 100; i < 100 + FRAME_WINDOW_SIZE; i++) {
+ assertTrue(w.contains(i));
+ assertFalse(w.isTooHigh(i));
+ }
+ assertFalse(w.contains(100 + FRAME_WINDOW_SIZE));
+ assertTrue(w.isTooHigh(100 + FRAME_WINDOW_SIZE));
}
@Test
public void testWindowJumping() {
FrameWindow w = new FrameWindowImpl();
- for(int i = 0; i < 100; i += 13) {
+ // Base of the window is 0
+ for(int i = 0; i < FRAME_WINDOW_SIZE; i++) assertTrue(w.contains(i));
+ assertFalse(w.contains(FRAME_WINDOW_SIZE));
+ assertFalse(w.isTooHigh(FRAME_WINDOW_SIZE - 1));
+ assertTrue(w.isTooHigh(FRAME_WINDOW_SIZE));
+ // Remove all numbers except 0 and 5
+ for(int i = 1; i < 5; i++) assertTrue(w.remove(i));
+ for(int i = 6; i < FRAME_WINDOW_SIZE; i++) assertTrue(w.remove(i));
+ // Base of the window should still be 0
+ assertTrue(w.contains(0));
+ for(int i = 1; i < 5; i++) assertFalse(w.contains(i));
+ assertTrue(w.contains(5));
+ for(int i = 6; i < FRAME_WINDOW_SIZE; i++) assertFalse(w.contains(i));
+ assertFalse(w.contains(FRAME_WINDOW_SIZE));
+ assertFalse(w.isTooHigh(FRAME_WINDOW_SIZE - 1));
+ assertTrue(w.isTooHigh(FRAME_WINDOW_SIZE));
+ // Remove 0
+ assertTrue(w.remove(0));
+ // Base of the window should now be 5
+ for(int i = 0; i < 5; i++) assertFalse(w.contains(i));
+ assertTrue(w.contains(5));
+ for(int i = 6; i < FRAME_WINDOW_SIZE; i++) assertFalse(w.contains(i));
+ for(int i = FRAME_WINDOW_SIZE; i < FRAME_WINDOW_SIZE + 5; i++) {
assertTrue(w.contains(i));
- w.remove(i);
+ }
+ assertFalse(w.contains(FRAME_WINDOW_SIZE + 5));
+ assertFalse(w.isTooHigh(FRAME_WINDOW_SIZE + 4));
+ assertTrue(w.isTooHigh(FRAME_WINDOW_SIZE + 5));
+ // Remove all numbers except 5
+ for(int i = FRAME_WINDOW_SIZE; i < FRAME_WINDOW_SIZE + 5; i++) {
+ assertTrue(w.remove(i));
+ }
+ // Base of the window should still be 5
+ assertTrue(w.contains(5));
+ for(int i = 6; i < FRAME_WINDOW_SIZE + 5; i++) {
assertFalse(w.contains(i));
}
- }
-
- @Test
- public void testWindowUpperLimit() {
- FrameWindow w = new FrameWindowImpl();
- // Centre is 0, highest value in window is 15
- for(int i = 0; i < 16; i++) assertTrue(w.contains(i));
- assertFalse(w.remove(16));
- assertTrue(w.remove(15));
- assertFalse(w.remove(15));
- // Centre is 16, highest value in window is 31
- for(int i = 0; i < 32; i++) assertEquals(i != 15, w.contains(i));
- assertFalse(w.remove(32));
- assertTrue(w.remove(31));
- // Values greater than 2^32 - 1 should never be allowed
- assertTrue(w.advance(MAX_32_BIT_UNSIGNED - 1));
- assertTrue(w.remove(MAX_32_BIT_UNSIGNED - 1));
- assertTrue(w.remove(MAX_32_BIT_UNSIGNED));
- try {
- w.remove(MAX_32_BIT_UNSIGNED + 1);
- fail();
- } catch(IllegalArgumentException expected) {}
- }
-
- @Test
- public void testAdvance() {
- FrameWindow w = new FrameWindowImpl();
- long centre = 0;
- for(int i = 0; i < 10; i++) {
- long bottom = Math.max(0, centre - FRAME_WINDOW_SIZE / 2);
- long top = Math.min(MAX_32_BIT_UNSIGNED,
- centre + FRAME_WINDOW_SIZE / 2 - 1);
- if(bottom > 0) assertFalse(w.contains(bottom - 1));
- for(long j = bottom; j <= top; j++) assertTrue(w.contains(j));
- if(top < MAX_32_BIT_UNSIGNED) assertFalse(w.contains(top + 1));
- centre += 12345;
- assertTrue(w.advance(centre));
+ assertFalse(w.contains(FRAME_WINDOW_SIZE + 5));
+ assertFalse(w.isTooHigh(FRAME_WINDOW_SIZE + 4));
+ assertTrue(w.isTooHigh(FRAME_WINDOW_SIZE + 5));
+ // Remove 5
+ assertTrue(w.remove(5));
+ // Base of the window should now be FRAME_WINDOW_SIZE + 5
+ for(int i = 0; i < FRAME_WINDOW_SIZE + 5; i++) {
+ assertFalse(w.contains(i));
}
- }
-
- @Test
- public void testWindowLowerLimit() {
- FrameWindow w = new FrameWindowImpl();
- // Centre is 0, negative values should never be allowed
- try {
- w.remove(-1);
- fail();
- } catch(IllegalArgumentException expected) {}
- // Slide the window twice
- assertTrue(w.remove(15));
- assertTrue(w.remove(16));
- // Centre is 17, lowest value in window is 1
- assertFalse(w.remove(0));
- assertTrue(w.remove(1));
- // Slide the window
- assertTrue(w.remove(25));
- // Centre is 26, lowest value in window is 10
- assertFalse(w.remove(9));
- assertTrue(w.remove(10));
+ for(int i = FRAME_WINDOW_SIZE + 5; i < FRAME_WINDOW_SIZE * 2 + 5; i++) {
+ assertTrue(w.contains(i));
+ }
+ assertFalse(w.contains(FRAME_WINDOW_SIZE * 2 + 5));
+ assertFalse(w.isTooHigh(FRAME_WINDOW_SIZE * 2 + 4));
+ assertTrue(w.isTooHigh(FRAME_WINDOW_SIZE * 2 + 5));
}
}
\ No newline at end of file