Recreated the PiecesTracker for optimal performance.

src/com/frostwire/jlibtorrent/FileEntry.java

@@ -32,7 +32,7 @@ public String getPath() {
 
     /**
      * The path which this is a symlink to, or empty if this is
-     * not a symlink. This field is only used if the ``symlink_attribute`` is set.
+     * not a symlink. This field is only used if the {@code symlink_attribute} is set.
      *
      * @return
      */
@@ -50,7 +50,7 @@ public long getOffset() {
     }
 
     /**
-     * the size of the file (in bytes) and ``offset`` is the byte offset
+     * The size of the file (in bytes) and {@code offset} is the byte offset
      * of the file within the torrent. i.e. the sum of all the sizes of the files
      * before it in the list.
      *
@@ -61,10 +61,10 @@ public long getSize() {
     }
 
     /**
-     * the offset in the file where the storage should start. The normal
+     * The offset in the file where the storage should start. The normal
      * case is to have this set to 0, so that the storage starts saving data at the start
      * if the file. In cases where multiple files are mapped into the same file though,
-     * the ``file_base`` should be set to an offset so that the different regions do
+     * the {@code file_base} should be set to an offset so that the different regions do
      * not overlap. This is used when mapping "unselected" files into a so-called part
      * file.
      *
@@ -75,7 +75,7 @@ public long getFileBase() {
     }
 
     /**
-     * the modification time of this file specified in posix time.
+     * The modification time of this file specified in posix time.
      *
      * @return
      */
@@ -84,7 +84,7 @@ public int getMTime() {
     }
 
     /**
-     * a sha-1 hash of the content of the file, or zeroes, if no
+     * The sha-1 hash of the content of the file, or zeroes, if no
      * file hash was present in the torrent file. It can be used to potentially
      * find alternative sources for the file.
      *
@@ -95,9 +95,9 @@ public Sha1Hash getFileHash() {
     }
 
     /**
-     * set to true for files that are not part of the data of the torrent.
+     * Set to true for files that are not part of the data of the torrent.
      * They are just there to make sure the next file is aligned to a particular byte offset
-     * or piece boundry. These files should typically be hidden from an end user. They are
+     * or piece boundary. These files should typically be hidden from an end user. They are
      * not written to disk.
      *
      * @return
@@ -107,7 +107,7 @@ public boolean isPadFile() {
     }
 
     /**
-     * true if the file was marked as hidden (on windows).
+     * True if the file was marked as hidden (on windows).
      *
      * @return
      */
@@ -116,7 +116,7 @@ public boolean hasHiddenAttribute() {
     }
 
     /**
-     * true if the file was marked as executable (posix)
+     * True if the file was marked as executable (posix)
      *
      * @return
      */
@@ -125,8 +125,8 @@ public boolean hasExecutableAttribute() {
     }
 
     /**
-     * true if the file was a symlink. If this is the case
-     * the ``symlink_index`` refers to a string which specifies the original location
+     * True if the file was a symlink. If this is the case
+     * the {@code symlink_index} refers to a string which specifies the original location
      * where the data for this file was found.
      *
      * @return

src/com/frostwire/jlibtorrent/PiecesTracker.java

@@ -0,0 +1,84 @@
+package com.frostwire.jlibtorrent;
+
+import java.util.ArrayList;
+
+/**
+ * @author gubatron
+ * @author aldenml
+ */
+public final class PiecesTracker {
+
+    private final int numFiles;
+    private final int numPieces;
+
+    private final int[][] files;
+    private final long[][] sizes;
+    private final boolean[] complete;
+
+    public PiecesTracker(TorrentInfo ti) {
+        this.numFiles = ti.getNumFiles();
+        this.numPieces = ti.getNumPieces();
+
+        this.files = new int[numFiles][];
+        this.sizes = new long[numFiles][];
+        this.complete = new boolean[numPieces];
+
+        for (int fileIndex = 0; fileIndex < numFiles; fileIndex++) {
+            FileEntry fe = ti.getFileAt(fileIndex);
+            long size = fe.getSize();
+            int firstPiece = ti.mapFile(fileIndex, 0, 1).getPiece();
+            int lastPiece = ti.mapFile(fileIndex, size - 1, 1).getPiece();
+
+            int numSlices = lastPiece - firstPiece + 1;
+            files[fileIndex] = new int[numSlices];
+            sizes[fileIndex] = new long[numSlices];
+
+            for (int pieceIndex = firstPiece; pieceIndex <= lastPiece; pieceIndex++) {
+                int index = pieceIndex - firstPiece;
+
+                files[fileIndex][index] = pieceIndex;
+
+                ArrayList<FileSlice> slices = ti.mapBlock(pieceIndex, 0, ti.getPieceSize(pieceIndex));
+                for (FileSlice slice : slices) {
+                    if (slice.getFileIndex() == fileIndex) {
+                        sizes[fileIndex][index] = slice.getSize();
+                    }
+                }
+            }
+        }
+    }
+
+    public int getNumFiles() {
+        return numFiles;
+    }
+
+    public int getNumPieces() {
+        return numPieces;
+    }
+
+    public boolean isComplete(int pieceIndex) throws IllegalArgumentException {
+        return complete[pieceIndex];
+    }
+
+    public void setComplete(int pieceIndex, boolean complete) throws IllegalArgumentException {
+        this.complete[pieceIndex] = complete;
+    }
+
+    public long getSequentialDownloaded(int fileIndex) {
+        int[] pieces = files[fileIndex];
+
+        long downloaded = 0;
+
+        for (int i = 0; i < pieces.length; i++) {
+            int pieceIndex = pieces[i];
+
+            if (complete[pieceIndex]) {
+                downloaded += sizes[fileIndex][i];
+            } else {
+                break;
+            }
+        }
+
+        return downloaded;
+    }
+}

src/com/frostwire/jlibtorrent/demo/PieceMap.java

@@ -1,11 +1,9 @@
 package com.frostwire.jlibtorrent.demo;
 
-import com.frostwire.jlibtorrent.FileSlice;
-import com.frostwire.jlibtorrent.FileSliceTracker;
+import com.frostwire.jlibtorrent.PiecesTracker;
 import com.frostwire.jlibtorrent.TorrentInfo;
 
 import java.io.File;
-import java.util.ArrayList;
 
 /**
  * @author gubatron
@@ -23,33 +21,19 @@ public static void main(String[] args) throws Throwable {
 
         TorrentInfo ti = new TorrentInfo(torrentFile);
 
+        int numFiles = ti.getNumFiles();
         int numPieces = ti.getNumPieces();
 
         System.out.println("Num Pieces: " + numPieces);
 
-        FileSliceTracker[] trackers = new FileSliceTracker[ti.getNumFiles()];
+        PiecesTracker tracker = new PiecesTracker(ti);
 
-        for (int i = 0; i < numPieces; i++) {
-            ArrayList<FileSlice> slices = ti.mapBlock(i, 0, ti.getPieceSize(i));
-            for (FileSlice slice : slices) {
-                int fileIndex = slice.getFileIndex();
-
-                if (trackers[fileIndex] == null) {
-                    trackers[fileIndex] = new FileSliceTracker(fileIndex);
-                }
-
-                trackers[fileIndex].addSlice(i, slice);
-            }
+        for (int i = 0; i < numPieces / 2; i++) {
+            tracker.setComplete(i, true);
         }
 
-        int totalSlices = 0;
-
-        for (FileSliceTracker tracker : trackers) {
-            int numSlices = tracker.getNumSlices();
-            System.out.println("File Index: " + tracker.getFileIndex() + ", slices: " + numSlices);
-            totalSlices = totalSlices + numSlices;
+        for (int i = 0; i < numFiles; i++) {
+            System.out.println("File index (seq)completed: " + tracker.getSequentialDownloaded(i));
         }
-
-        System.out.println("Total Slices: " + totalSlices);
     }
 }