Automated [] rollback of [].

*** Reason for rollback ***

New ZipCombiner creates malformed output ZIP files when input ZIP files contain more than 65535 entries, the maximum amount for non-64-bit ZIP files.

*** Original change description ***

Rewrite of ZipCombiner to improve performance and maintainability. Added devtools/build/zip to allow reading and writing of ZIP files without requiring decompressing file data to manipulate them.

ZipCombiner API has some changes. ZipCombiner#addZip takes a File instead of InputStream. ZipCombiner#addFile takes a ZipFileEntry instead of DirectoryEntryInfo

--
MOS_MIGRATED_REVID=90279976

12 files changed, 1409 insertions, 2069 deletions

diff --git a/src/java_tools/singlejar/java/com/google/devtools/build/zip/ExtraData.java b/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/ExtraData.java
index 7bbe0c3dd9..2e8cb75e02 100644
--- a/src/java_tools/singlejar/java/com/google/devtools/build/zip/ExtraData.java
+++ b/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/ExtraData.java
@@ -12,7 +12,7 @@
 // See the License for the specific language governing permissions and
 // limitations under the License.
 
-package com.google.devtools.build.zip;
+package com.google.devtools.build.singlejar;
 
 /**
  * A holder class for extra data in a ZIP entry.
@@ -21,7 +21,7 @@ package com.google.devtools.build.zip;
  * byte array passed into this class or returned from this class may not be
  * modified.
  */
-public final class ExtraData {
+final class ExtraData {
 
   private final short id;
   private final byte[] data;
diff --git a/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/JarUtils.java b/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/JarUtils.java
index a21f58307d..a9c8ee3f65 100644
--- a/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/JarUtils.java
+++ b/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/JarUtils.java
@@ -14,8 +14,6 @@
 
 package com.google.devtools.build.singlejar;
 
-import com.google.devtools.build.zip.ExtraData;
-
 import java.io.IOException;
 import java.util.Date;
 
diff --git a/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/JavaIoFileSystem.java b/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/JavaIoFileSystem.java
index f66f23dba2..0da6e33040 100644
--- a/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/JavaIoFileSystem.java
+++ b/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/JavaIoFileSystem.java
@@ -37,11 +37,6 @@ public final class JavaIoFileSystem implements SimpleFileSystem {
   }
 
   @Override
-  public File getFile(String filename) throws IOException {
-    return new File(filename);
-  }
-
-  @Override
   public boolean delete(String filename) {
     return new File(filename).delete();
   }
diff --git a/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/SimpleFileSystem.java b/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/SimpleFileSystem.java
index 1bacc3c529..844f12b714 100644
--- a/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/SimpleFileSystem.java
+++ b/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/SimpleFileSystem.java
@@ -16,7 +16,6 @@ package com.google.devtools.build.singlejar;
 
 import com.google.devtools.build.singlejar.OptionFileExpander.OptionFileProvider;
 
-import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
@@ -37,11 +36,6 @@ public interface SimpleFileSystem extends OptionFileProvider {
   OutputStream getOutputStream(String filename) throws IOException;
 
   /**
-   * Returns the File object in the file system for this filename.
-   */
-  File getFile(String filename) throws IOException;
-
-  /**
    * Delete the file with the given name and return whether deleting it was
    * successfull.
    */
diff --git a/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/SingleJar.java b/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/SingleJar.java
index 8fd677e1b7..4551fd1813 100644
--- a/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/SingleJar.java
+++ b/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/SingleJar.java
@@ -19,7 +19,6 @@ import com.google.devtools.build.singlejar.ZipCombiner.OutputMode;
 
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
-import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.util.ArrayList;
@@ -81,10 +80,10 @@ public class SingleJar {
   protected boolean includeBuildData = true;
 
   /** List of build information properties files */
-  protected List<String> buildInformationFiles = new ArrayList<>();
+  protected List<String> buildInformationFiles = new ArrayList<String>();
 
   /** Extraneous build informations (key=value) */
-  protected List<String> buildInformations = new ArrayList<>();
+  protected List<String> buildInformations = new ArrayList<String>();
 
   /** The (optional) native executable that will be prepended to this JAR. */
   private String launcherBin = null;
@@ -224,8 +223,21 @@ public class SingleJar {
 
       // Copy the jars into the jar file.
       for (String inputJar : inputJars) {
-        File jar = fileSystem.getFile(inputJar);
-        combiner.addZip(jar);
+        InputStream in = fileSystem.getInputStream(inputJar);
+        try {
+          combiner.addZip(inputJar, in);
+          InputStream inToClose = in;
+          in = null;
+          inToClose.close();
+        } finally {
+          if (in != null) {
+            try {
+              in.close();
+            } catch (IOException e) {
+              // Preserve original exception.
+            }
+          }
+        }
       }
 
       // Close the output file. If something goes wrong here, delete the file.
diff --git a/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/ZipCombiner.java b/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/ZipCombiner.java
index e64d4b82c5..d38c6d4493 100644
--- a/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/ZipCombiner.java
+++ b/src/java_tools/singlejar/java/com/google/devtools/build/singlejar/ZipCombiner.java
@@ -14,45 +14,44 @@
 
 package com.google.devtools.build.singlejar;
 
+import static java.nio.charset.StandardCharsets.ISO_8859_1;
 import static java.nio.charset.StandardCharsets.UTF_8;
 
 import com.google.devtools.build.singlejar.ZipEntryFilter.CustomMergeStrategy;
 import com.google.devtools.build.singlejar.ZipEntryFilter.StrategyCallback;
-import com.google.devtools.build.zip.ExtraData;
-import com.google.devtools.build.zip.ZipFileEntry;
-import com.google.devtools.build.zip.ZipFileEntry.Compression;
-import com.google.devtools.build.zip.ZipReader;
-import com.google.devtools.build.zip.ZipUtil;
-import com.google.devtools.build.zip.ZipWriter;
 
 import java.io.BufferedOutputStream;
 import java.io.ByteArrayInputStream;
 import java.io.ByteArrayOutputStream;
-import java.io.File;
+import java.io.EOFException;
+import java.io.FilterOutputStream;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.OutputStream;
-import java.nio.file.Files;
-import java.nio.file.StandardCopyOption;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Calendar;
 import java.util.Date;
+import java.util.GregorianCalendar;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
-import java.util.Map.Entry;
 import java.util.concurrent.atomic.AtomicBoolean;
 import java.util.zip.CRC32;
+import java.util.zip.DataFormatException;
 import java.util.zip.Deflater;
-import java.util.zip.DeflaterInputStream;
 import java.util.zip.Inflater;
-import java.util.zip.InflaterInputStream;
 
 import javax.annotation.Nullable;
+import javax.annotation.concurrent.NotThreadSafe;
 
 /**
  * An object that combines multiple ZIP files into a single file. It only
  * supports a subset of the ZIP format, specifically:
  * <ul>
  *   <li>It only supports STORE and DEFLATE storage methods.</li>
- *   <li>It only supports 32-bit ZIP files.</li>
+ *   <li>There may be no data before the first file or between files.</li>
+ *   <li>It ignores any data after the last file.</li>
  * </ul>
  *
  * <p>These restrictions are also present in the JDK implementations
@@ -69,554 +68,1551 @@ import javax.annotation.Nullable;
  * <p>Also see:
  * <a href="http://www.pkware.com/documents/casestudies/APPNOTE.TXT">ZIP format</a>
  */
-public class ZipCombiner implements AutoCloseable {
-  public static final Date DOS_EPOCH = new Date(ZipUtil.DOS_EPOCH);
+@NotThreadSafe
+public final class ZipCombiner implements AutoCloseable {
+
+  /**
+   * A Date set to the 1/1/1980, 00:00:00, the minimum value that can be stored
+   * in a ZIP file.
+   */
+  public static final Date DOS_EPOCH = new GregorianCalendar(1980, 0, 1, 0, 0, 0).getTime();
+
+  private static final int DEFAULT_CENTRAL_DIRECTORY_BLOCK_SIZE = 1048576; // 1 MB for each block
+
+  // The following constants are ZIP-specific.
+  private static final int LOCAL_FILE_HEADER_MARKER = 0x04034b50;
+  private static final int DATA_DESCRIPTOR_MARKER = 0x08074b50;
+  private static final int CENTRAL_DIRECTORY_MARKER = 0x02014b50;
+  private static final int END_OF_CENTRAL_DIRECTORY_MARKER = 0x06054b50;
+
+  private static final int FILE_HEADER_BUFFER_SIZE = 30;
+
+  private static final int VERSION_TO_EXTRACT_OFFSET = 4;
+  private static final int GENERAL_PURPOSE_FLAGS_OFFSET = 6;
+  private static final int COMPRESSION_METHOD_OFFSET = 8;
+  private static final int MTIME_OFFSET = 10;
+  private static final int MDATE_OFFSET = 12;
+  private static final int CRC32_OFFSET = 14;
+  private static final int COMPRESSED_SIZE_OFFSET = 18;
+  private static final int UNCOMPRESSED_SIZE_OFFSET = 22;
+  private static final int FILENAME_LENGTH_OFFSET = 26;
+  private static final int EXTRA_LENGTH_OFFSET = 28;
+
+  private static final int DIRECTORY_ENTRY_BUFFER_SIZE = 46;
+
+  // Set if the size, compressed size and CRC are set to zero, and present in
+  // the data descriptor after the data.
+  private static final int SIZE_MASKED_FLAG = 1 << 3;
+
+  private static final int STORED_METHOD = 0;
+  private static final int DEFLATE_METHOD = 8;
+
+  private static final int VERSION_STORED = 10; // Version 1.0
+  private static final int VERSION_DEFLATE = 20; // Version 2.0
+
+  private static final long MAXIMUM_DATA_SIZE = 0xffffffffL;
+
+  // This class relies on the buffer to have sufficient space for a complete
+  // file name. 2^16 is the maximum number of bytes in a file name.
+  private static final int BUFFER_SIZE = 65536;
+
+  /** An empty entry used to skip files that have already been copied (or skipped). */
+  private static final FileEntry COPIED_FILE_ENTRY = new FileEntry(null, null, 0);
+
+  /** An empty entry used to mark files that have already been renamed. */
+  private static final FileEntry RENAMED_FILE_ENTRY = new FileEntry(null, null, 0);
+
+  /** A zero length array of ExtraData. */
+  public static final ExtraData[] NO_EXTRA_ENTRIES = new ExtraData[0];
+
   /**
    * Whether to compress or decompress entries.
    */
   public enum OutputMode {
+
     /**
      * Output entries using any method.
      */
     DONT_CARE,
+
     /**
-     * Output all entries using DEFLATE method, except directory entries. It is always more
-     * efficient to store directory entries uncompressed.
+     * Output all entries using DEFLATE method, except directory entries. It is
+     * always more efficient to store directory entries uncompressed.
      */
     FORCE_DEFLATE,
+
     /**
      * Output all entries using STORED method.
      */
-    FORCE_STORED,
+    FORCE_STORED;
   }
 
-  /**
-   * The type of action to take for a ZIP file entry.
-   */
-  private enum ActionType {
-    /**
-     * Skip the entry.
-     */
-    SKIP,
+  // A two-element enum for copyOrSkip type methods.
+  private static enum SkipMode {
+
     /**
-     * Copy the entry.
+     * Copy the read data to the output stream.
      */
     COPY,
+
     /**
-     * Rename the entry.
-     */
-    RENAME,
-    /**
-     * Merge the entry.
+     * Do not write anything to the output stream.
      */
-    MERGE;
+    SKIP;
   }
 
   /**
-   * The action to take for a ZIP file entry.
+   * Stores internal information about merges or skips.
    */
-  private static final class EntryAction {
-    private final ActionType type;
-    @Nullable private final Date date;
-    @Nullable private final String newName;
-    @Nullable private final CustomMergeStrategy strategy;
-    @Nullable private final ByteArrayOutputStream mergeBuffer;
+  private static final class FileEntry {
 
-    /**
-     * Create an action of the specified type with no extra details.
-     *
-     * @param type the type of action
-     */
-    public EntryAction(ActionType type) {
-      this(type, null, null, null, null);
+    /** If null, the file should be skipped. Otherwise, it should be merged. */
+    private final CustomMergeStrategy mergeStrategy;
+    private final ByteArrayOutputStream outputBuffer;
+    private final int dosTime;
+
+    private FileEntry(CustomMergeStrategy mergeStrategy, ByteArrayOutputStream outputBuffer,
+        int dosTime) {
+      this.mergeStrategy = mergeStrategy;
+      this.outputBuffer = outputBuffer;
+      this.dosTime = dosTime;
     }
+  }
 
-    /**
-     * Create a duplicate action with a different {@link ActionType}.
-     *
-     * @param type the type of action
-     * @param action the action to copy
-     */
-    public EntryAction(ActionType type, EntryAction action) {
-      this(type, action.getDate(), action.getNewName(), action.getStrategy(),
-          action.getMergeBuffer());
+  /**
+   * The directory entry info used for files whose extra directory entry info is not given
+   * explicitly. It uses {@code -1} for {@link DirectoryEntryInfo#withMadeByVersion(short)}, which
+   * indicates it will be set to the same version as "needed to extract."
+   *
+   * <p>The {@link DirectoryEntryInfo#withExternalFileAttribute(int)} value is set to {@code 0},
+   * whose meaning depends on the value of {@code madeByVersion}, but is usually a reasonable
+   * default.
+   */
+  public static final DirectoryEntryInfo DEFAULT_DIRECTORY_ENTRY_INFO =
+      new DirectoryEntryInfo((short) -1, 0);
+
+  /**
+   * Contains information related to a zip entry that is stored in the central directory record.
+   * This does not contain all the information stored in the central directory record, only the
+   * information that can be customized and is not automatically calculated or detected.
+   */
+  public static final class DirectoryEntryInfo {
+    private final short madeByVersion;
+    private final int externalFileAttribute;
+
+    private DirectoryEntryInfo(short madeByVersion, int externalFileAttribute) {
+      this.madeByVersion = madeByVersion;
+      this.externalFileAttribute = externalFileAttribute;
     }
 
     /**
-     * Create an action of the specified type and details.
-     *
-     * @param type the type of action
-     * @param date the custom date to set on the entry
-     * @param newName the custom name to create the entry as
-     * @param strategy the {@link CustomMergeStrategy} to use for merging this entry
-     * @param mergeBuffer the output stream to use for merge results
+     * This will be written as "made by" version in the central directory.
+     * If -1 (default) then "made by" will be the same to version "needed to extract".
      */
-    public EntryAction(ActionType type, Date date, String newName, CustomMergeStrategy strategy,
-        ByteArrayOutputStream mergeBuffer) {
-      checkArgument(!(type == ActionType.RENAME && newName == null),
-          "NewName must not be null if the ActionType is RENAME.");
-      checkArgument(!(type == ActionType.MERGE && strategy == null),
-          "Strategy must not be null if the ActionType is MERGE.");
-      checkArgument(!(type == ActionType.MERGE && mergeBuffer == null),
-          "MergeBuffer must not be null if the ActionType is MERGE.");
-      this.type = type;
-      this.date = date;
-      this.newName = newName;
-      this.strategy = strategy;
-      this.mergeBuffer = mergeBuffer;
+    public DirectoryEntryInfo withMadeByVersion(short madeByVersion) {
+      return new DirectoryEntryInfo(madeByVersion, externalFileAttribute);
     }
 
     /**
-     * @return the type
+     * This will be written as external file attribute. The meaning of this depends upon the value
+     * set with {@link #withMadeByVersion(short)}. If that value indicates a Unix source, then this
+     * value has the file mode and permission bits in the upper two bytes (e.g. possibly
+     * {@code 0100644} for a regular file).
      */
-    public ActionType getType() {
-      return type;
+    public DirectoryEntryInfo withExternalFileAttribute(int externalFileAttribute) {
+      return new DirectoryEntryInfo(madeByVersion, externalFileAttribute);
     }
-    /**
-     * @return the date
-     */
-    public Date getDate() {
-      return date;
+  }
+
+  /**
+   * The central directory, which is grown as required; instead of using a single large buffer, we
+   * store a sequence of smaller buffers. With a single large buffer, whenever we grow the buffer by
+   * 2x, we end up requiring 3x the memory temporarily, which can lead to OOM problems even if there
+   * would still be enough memory.
+   *
+   * <p>The invariants for the fields are as follows:
+   * <ul>
+   *   <li>All blocks must have the same size.
+   *   <li>The list of blocks must contain all blocks, including the current block (even if empty).
+   *   <li>The current block offset must apply to the last block in the list, which is
+   *       simultaneously the current block.
+   *   <li>The current block may only be {@code null} if the list is empty.
+   * </ul>
+   */
+  private static final class CentralDirectory {
+    private final int blockSize; // We allow this to be overridden for testing.
+    private List<byte[]> blockList = new ArrayList<>();
+    private byte[] currentBlock;
+    private int currentBlockOffset = 0;
+    private int size = 0;
+
+    CentralDirectory(int centralDirectoryBlockSize) {
+      this.blockSize = centralDirectoryBlockSize;
     }
+
     /**
-     * @return the new name
+     * Appends the given data to the central directory and returns the start
+     * offset within the central directory to allow back-patching.
      */
-    public String getNewName() {
-      return newName;
+    int writeToCentralDirectory(byte[] b, int off, int len) {
+      checkArgument(len >= 0);
+      int offsetStarted = size;
+      while (len > 0) {
+        if (currentBlock == null
+            || currentBlockOffset >= currentBlock.length) {
+          currentBlock = new byte[blockSize];
+          currentBlockOffset = 0;
+          blockList.add(currentBlock);
+        }
+        int maxCopy = Math.min(blockSize - currentBlockOffset, len);
+        System.arraycopy(b, off, currentBlock, currentBlockOffset, maxCopy);
+        off += maxCopy;
+        len -= maxCopy;
+        size += maxCopy;
+        currentBlockOffset += maxCopy;
+      }
+      return offsetStarted;
+    }
+
+    /** Calls through to {@link #writeToCentralDirectory(byte[], int, int)}. */
+    int writeToCentralDirectory(byte[] b) {
+      return writeToCentralDirectory(b, 0, b.length);
     }
+
     /**
-     * @return the strategy
+     * Writes an unsigned int in little-endian byte order to the central directory at the
+     * given offset. Does not perform range checking.
      */
-    public CustomMergeStrategy getStrategy() {
-      return strategy;
+    void setUnsignedInt(int offset, int value) {
+      blockList.get(cdIndex(offset + 0))[cdOffset(offset + 0)] = (byte) (value & 0xff);
+      blockList.get(cdIndex(offset + 1))[cdOffset(offset + 1)] = (byte) ((value >> 8) & 0xff);
+      blockList.get(cdIndex(offset + 2))[cdOffset(offset + 2)] = (byte) ((value >> 16) & 0xff);
+      blockList.get(cdIndex(offset + 3))[cdOffset(offset + 3)] = (byte) ((value >> 24) & 0xff);
+    }
+
+    private int cdIndex(int offset) {
+      return offset / blockSize;
     }
+
+    private int cdOffset(int offset) {
+      return offset % blockSize;
+    }
+
     /**
-     * @return the mergeBuffer
+     * Writes the central directory to the given output stream and returns the size, i.e., the
+     * number of bytes written.
      */
-    public ByteArrayOutputStream getMergeBuffer() {
-      return mergeBuffer;
+    int writeTo(OutputStream out) throws IOException {
+      for (int i = 0; i < blockList.size() - 1; i++) {
+        out.write(blockList.get(i));
+      }
+      if (currentBlock != null) {
+        out.write(currentBlock, 0, currentBlockOffset);
+      }
+      return size;
     }
   }
 
-  private final class FilterCallback implements StrategyCallback {
-    private String filename;
-    private final AtomicBoolean called = new AtomicBoolean();
+  /**
+   * An output stream that counts how many bytes were written.
+   */
+  private static final class ByteCountingOutputStream extends FilterOutputStream {
+    private long bytesWritten = 0L;
 
-    public void resetForFile(String filename) {
-      this.filename = filename;
-      this.called.set(false);
+    ByteCountingOutputStream(OutputStream out) {
+      super(out);
     }
 
-    @Override public void skip() throws IOException {
-      checkCall();
-      actions.put(filename, new EntryAction(ActionType.SKIP));
+    @Override
+    public void write(byte[] b, int off, int len) throws IOException {
+      out.write(b, off, len);
+      bytesWritten += len;
     }
 
-    @Override public void copy(Date date) throws IOException {
-      checkCall();
-      actions.put(filename, new EntryAction(ActionType.COPY, date, null, null, null));
+    @Override
+    public void write(int b) throws IOException {
+      out.write(b);
+      bytesWritten++;
     }
+  }
 
-    @Override public void rename(String newName, Date date) throws IOException {
-      checkCall();
-      actions.put(filename, new EntryAction(ActionType.RENAME, date, newName, null, null));
-    }
+  private final OutputMode mode;
+  private final ZipEntryFilter entryFilter;
 
-    @Override public void customMerge(Date date, CustomMergeStrategy strategy) throws IOException {
-      checkCall();
-      actions.put(filename, new EntryAction(ActionType.MERGE, date, null, strategy,
-          new ByteArrayOutputStream()));
+  private final ByteCountingOutputStream out;
+
+  // An input buffer to allow reading blocks of data. Keeping it here avoids
+  // another copy operation that would be required by the BufferedInputStream.
+  // The valid data is between bufferOffset and bufferOffset+bufferLength (exclusive).
+  private final byte[] buffer = new byte[BUFFER_SIZE];
+  private int bufferOffset = 0;
+  private int bufferLength = 0;
+
+  private String currentInputFile;
+
+  // An intermediate buffer for the file header data. Keeping it here avoids
+  // creating a new buffer for every entry.
+  private final byte[] headerBuffer = new byte[FILE_HEADER_BUFFER_SIZE];
+
+  // An intermediate buffer for a central directory entry. Keeping it here
+  // avoids creating a new buffer for every entry.
+  private final byte[] directoryEntryBuffer = new byte[DIRECTORY_ENTRY_BUFFER_SIZE];
+
+  // The Inflater is a class member to avoid creating a new instance for every
+  // entry in the ZIP file.
+  private final Inflater inflater = new Inflater(true);
+
+  // The contents of this buffer are never read. The Inflater is only used to
+  // determine the length of the compressed data, and the buffer is a throw-
+  // away buffer for the decompressed data.
+  private final byte[] inflaterBuffer = new byte[BUFFER_SIZE];
+
+  private final Map<String, FileEntry> fileNames = new HashMap<>();
+
+  private final CentralDirectory centralDirectory;
+  private int fileCount = 0;
+
+  private boolean finished = false;
+
+  // Package private for testing.
+  ZipCombiner(OutputMode mode, ZipEntryFilter entryFilter, OutputStream out,
+      int centralDirectoryBlockSize) {
+    this.mode = mode;
+    this.entryFilter = entryFilter;
+    this.out = new ByteCountingOutputStream(new BufferedOutputStream(out));
+    this.centralDirectory = new CentralDirectory(centralDirectoryBlockSize);
+  }
+
+  /**
+   * Creates a new instance with the given parameters. The {@code entryFilter}
+   * is called for every entry in the ZIP files and the combined ZIP file is
+   * written to {@code out}. The output mode determines whether entries must be
+   * written in compressed or decompressed form. Note that the result is
+   * invalid if an exception is thrown from any of the methods in this class,
+   * and before a call to {@link #close} or {@link #finish}.
+   */
+  public ZipCombiner(OutputMode mode, ZipEntryFilter entryFilter, OutputStream out) {
+    this(mode, entryFilter, out, DEFAULT_CENTRAL_DIRECTORY_BLOCK_SIZE);
+  }
+
+  /**
+   * Creates a new instance with the given parameters and the DONT_CARE mode.
+   */
+  public ZipCombiner(ZipEntryFilter entryFilter, OutputStream out) {
+    this(OutputMode.DONT_CARE, entryFilter, out);
+  }
+
+  /**
+   * Creates a new instance with the {@link CopyEntryFilter} as the filter and
+   * the given mode and output stream.
+   */
+  public ZipCombiner(OutputMode mode, OutputStream out) {
+    this(mode, new CopyEntryFilter(), out);
+  }
+
+  /**
+   * Creates a new instance with the {@link CopyEntryFilter} as the filter, the
+   * DONT_CARE mode and the given output stream.
+   */
+  public ZipCombiner(OutputStream out) {
+    this(OutputMode.DONT_CARE, new CopyEntryFilter(), out);
+  }
+
+  /**
+   * Returns whether the output zip already contains a file or directory with
+   * the given name.
+   */
+  public boolean containsFile(String filename) {
+    return fileNames.containsKey(filename);
+  }
+
+  /**
+   * Makes a write call to the output stream, and updates the current offset.
+   */
+  private void write(byte[] b, int off, int len) throws IOException {
+    out.write(b, off, len);
+  }
+
+  /** Calls through to {@link #write(byte[], int, int)}. */
+  private void write(byte[] b) throws IOException {
+    write(b, 0, b.length);
+  }
+
+  /**
+   * Reads at least one more byte into the internal buffer. This method must
+   * only be called when more data is necessary to correctly decode the ZIP
+   * format.
+   *
+   * <p>This method automatically compacts the existing data in the buffer by
+   * moving it to the beginning of the buffer.
+   *
+   * @throws EOFException if no more data is available from the input stream
+   * @throws IOException if the underlying stream throws one
+   */
+  private void readMoreData(InputStream in) throws IOException {
+    if ((bufferLength > 0) && (bufferOffset > 0)) {
+      System.arraycopy(buffer, bufferOffset, buffer, 0, bufferLength);
+    }
+    if (bufferLength >= buffer.length) {
+      // The buffer size is specifically chosen to avoid this situation.
+      throw new AssertionError("Internal error: buffer overrun.");
     }
+    bufferOffset = 0;
+    int bytesRead = in.read(buffer, bufferLength, buffer.length - bufferLength);
+    if (bytesRead <= 0) {
+      throw new EOFException();
+    }
+    bufferLength += bytesRead;
+  }
 
-    private void checkCall() {
-      checkState(called.compareAndSet(false, true), "The callback was already called once.");
+  /**
+   * Reads data until the buffer is filled with at least {@code length} bytes.
+   *
+   * @throws IllegalArgumentException if not 0 <= length <= buffer.length
+   * @throws IOException if the underlying input stream throws one or the end
+   *                     of the input stream is reached before the required
+   *                     number of bytes is read
+   */
+  private void readFully(InputStream in, int length) throws IOException {
+    checkArgument(length >= 0, "length too small: %s", length);
+    checkArgument(length <= buffer.length, "length too large: %s", length);
+    while (bufferLength < length) {
+      readMoreData(in);
     }
   }
 
-  /** Returns a {@link Deflater} for performing ZIP compression. */
-  private static Deflater getDeflater() {
-    return new Deflater(Deflater.DEFAULT_COMPRESSION, true);
+  /**
+   * Reads an unsigned short in little-endian byte order from the buffer at the
+   * given offset. Does not perform range checking.
+   */
+  private int getUnsignedShort(byte[] source, int offset) {
+    int a = source[offset + 0] & 0xff;
+    int b = source[offset + 1] & 0xff;
+    return (b << 8) | a;
   }
 
-  /** Returns a {@link Inflater} for performing ZIP decompression. */
-  private static Inflater getInflater() {
-    return new Inflater(true);
+  /**
+   * Reads an unsigned int in little-endian byte order from the buffer at the
+   * given offset. Does not perform range checking.
+   */
+  private long getUnsignedInt(byte[] source, int offset) {
+    int a = source[offset + 0] & 0xff;
+    int b = source[offset + 1] & 0xff;
+    int c = source[offset + 2] & 0xff;
+    int d = source[offset + 3] & 0xff;
+    return ((d << 24) | (c << 16) | (b << 8) | a) & 0xffffffffL;
   }
 
-  /** Copies all data from the input stream to the output stream. */
-  private static long copyStream(InputStream from, OutputStream to) throws IOException {
-    byte[] buf = new byte[0x1000];
-    long total = 0;
-    int r;
-    while ((r = from.read(buf)) != -1) {
-      to.write(buf, 0, r);
-      total += r;
-    }
-    return total;
+  /**
+   * Writes an unsigned short in little-endian byte order to the buffer at the
+   * given offset. Does not perform range checking.
+   */
+  private void setUnsignedShort(byte[] target, int offset, short value) {
+    target[offset + 0] = (byte) (value & 0xff);
+    target[offset + 1] = (byte) ((value >> 8) & 0xff);
   }
 
-  private final OutputMode mode;
-  private final ZipEntryFilter entryFilter;
-  private final FilterCallback callback;
-  private final ZipWriter out;
+  /**
+   * Writes an unsigned int in little-endian byte order to the buffer at the
+   * given offset. Does not perform range checking.
+   */
+  private void setUnsignedInt(byte[] target, int offset, int value) {
+    target[offset + 0] = (byte) (value & 0xff);
+    target[offset + 1] = (byte) ((value >> 8) & 0xff);
+    target[offset + 2] = (byte) ((value >> 16) & 0xff);
+    target[offset + 3] = (byte) ((value >> 24) & 0xff);
+  }
 
-  private final Map<String, ZipFileEntry> entries;
-  private final Map<String, EntryAction> actions;
+  /**
+   * Copies or skips {@code length} amount of bytes from the input stream to the
+   * output stream. If the internal buffer is not empty, those bytes are copied
+   * first. When the method returns, there may be more bytes remaining in the
+   * buffer.
+   *
+   * @throws IOException if the underlying stream throws one
+   */
+  private void copyOrSkipData(InputStream in, long length, SkipMode skip) throws IOException {
+    checkArgument(length >= 0);
+    while (length > 0) {
+      if (bufferLength == 0) {
+        readMoreData(in);
+      }
+      int bytesToWrite = (length < bufferLength) ? (int) length : bufferLength;
+      if (skip == SkipMode.COPY) {
+        write(buffer, bufferOffset, bytesToWrite);
+      }
+      bufferOffset += bytesToWrite;
+      bufferLength -= bytesToWrite;
+      length -= bytesToWrite;
+    }
+  }
 
   /**
-   * Creates a {@link ZipCombiner} for combining ZIP files using the specified {@link OutputMode},
-   * {@link ZipEntryFilter}, and destination {@link OutputStream}.
+   * Copies or skips {@code length} amount of bytes from the input stream to the
+   * output stream. If the internal buffer is not empty, those bytes are copied
+   * first. When the method returns, there may be more bytes remaining in the
+   * buffer. In addition to writing to the output stream, it also writes to the
+   * central directory.
    *
-   * @param mode the compression preference for the output ZIP file
-   * @param entryFilter the filter to use when adding ZIP files to the combined output
-   * @param out the {@link OutputStream} for writing the combined ZIP file
+   * @throws IOException if the underlying stream throws one
    */
-  public ZipCombiner(OutputMode mode, ZipEntryFilter entryFilter, OutputStream out) {
-    this.mode = mode;
-    this.entryFilter = entryFilter;
-    this.callback = new FilterCallback();
-    this.out = new ZipWriter(new BufferedOutputStream(out), UTF_8);
-    this.entries = new HashMap<>();
-    this.actions = new HashMap<>();
+  private void forkOrSkipData(InputStream in, long length, SkipMode skip) throws IOException {
+    checkArgument(length >= 0);
+    while (length > 0) {
+      if (bufferLength == 0) {
+        readMoreData(in);
+      }
+      int bytesToWrite = (length < bufferLength) ? (int) length : bufferLength;
+      if (skip == SkipMode.COPY) {
+        write(buffer, bufferOffset, bytesToWrite);
+        centralDirectory.writeToCentralDirectory(buffer, bufferOffset, bytesToWrite);
+      }
+      bufferOffset += bytesToWrite;
+      bufferLength -= bytesToWrite;
+      length -= bytesToWrite;
+    }
   }
 
   /**
-   * Creates a {@link ZipCombiner} for combining ZIP files using the specified
-   * {@link ZipEntryFilter}, and destination {@link OutputStream}. Uses the DONT_CARE
-   * {@link OutputMode}.
+   * A mutable integer reference value to allow returning two values from a
+   * method.
+   */
+  private static class MutableInt {
+
+    private int value;
+
+    MutableInt(int initialValue) {
+      this.value = initialValue;
+    }
+
+    public void setValue(int value) {
+      this.value = value;
+    }
+
+    public int getValue() {
+      return value;
+    }
+  }
+
+  /**
+   * Uses the inflater to decompress some data into the given buffer. This
+   * method performs no error checking on the input parameters and also does
+   * not update the buffer parameters of the input buffer (such as bufferOffset
+   * and bufferLength). It's only here to avoid code duplication.
    *
-   * @param entryFilter the filter to use when adding ZIP files to the combined output
-   * @param out the {@link OutputStream} for writing the combined ZIP file
+   * <p>The Inflater may not be in the finished state when this method is
+   * called.
+   *
+   * <p>This method returns 0 if it read data and reached the end of the
+   * DEFLATE stream without producing output. In that case, {@link
+   * Inflater#finished} is guaranteed to return true.
+   *
+   * @throws IOException if the underlying stream throws an IOException or if
+   *                     illegal data is encountered
    */
-  public ZipCombiner(ZipEntryFilter entryFilter, OutputStream out) {
-    this(OutputMode.DONT_CARE, entryFilter, out);
+  private int inflateData(InputStream in, byte[] dest, int off, int len, MutableInt consumed)
+      throws IOException {
+    // Defend against Inflater.finished() returning true.
+    consumed.setValue(0);
+    int bytesProduced = 0;
+    int bytesConsumed = 0;
+    while ((bytesProduced == 0) && !inflater.finished()) {
+      inflater.setInput(buffer, bufferOffset + bytesConsumed, bufferLength - bytesConsumed);
+      int remainingBefore = inflater.getRemaining();
+      try {
+        bytesProduced = inflater.inflate(dest, off, len);
+      } catch (DataFormatException e) {
+        throw new IOException("Invalid deflate stream in ZIP file.", e);
+      }
+      bytesConsumed += remainingBefore - inflater.getRemaining();
+      consumed.setValue(bytesConsumed);
+      if (bytesProduced == 0) {
+        if (inflater.needsDictionary()) {
+          // The DEFLATE algorithm as used in the ZIP file format does not
+          // require an additional dictionary.
+          throw new AssertionError("Inflater unexpectedly requires a dictionary.");
+        } else if (inflater.needsInput()) {
+          readMoreData(in);
+        } else if (inflater.finished()) {
+          return 0;
+        } else {
+          // According to the Inflater specification, this cannot happen.
+          throw new AssertionError("Inflater unexpectedly produced no output.");
+        }
+      }
+    }
+    return bytesProduced;
   }
 
   /**
-   * Creates a {@link ZipCombiner} for combining ZIP files using the specified {@link OutputMode},
-   * and destination {@link OutputStream}. Uses a {@link CopyEntryFilter} as the
-   * {@link ZipEntryFilter}.
+   * Copies or skips data from the input stream to the output stream. To
+   * determine the length of the data, the data is decompressed with the
+   * DEFLATE algorithm, which stores the length implicitly as part of the
+   * compressed data, using a combination of end markers and length indicators.
    *
-   * @param mode the compression preference for the output ZIP file
-   * @param out the {@link OutputStream} for writing the combined ZIP file
+   * @see <a href="http://www.ietf.org/rfc/rfc1951.txt">RFC 1951</a>
+   *
+   * @throws IOException if the underlying stream throws an IOException
    */
-  public ZipCombiner(OutputMode mode, OutputStream out) {
-    this(mode, new CopyEntryFilter(), out);
+  private long copyOrSkipDeflateData(InputStream in, SkipMode skip) throws IOException {
+    long bytesCopied = 0;
+    inflater.reset();
+    MutableInt consumedBytes = new MutableInt(0);
+    while (!inflater.finished()) {
+      // Neither the uncompressed data nor the length of it is used. The
+      // decompression is only required to determine the correct length of the
+      // compressed data to copy.
+      inflateData(in, inflaterBuffer, 0, inflaterBuffer.length, consumedBytes);
+      int bytesRead = consumedBytes.getValue();
+      if (skip == SkipMode.COPY) {
+        write(buffer, bufferOffset, bytesRead);
+      }
+      bufferOffset += bytesRead;
+      bufferLength -= bytesRead;
+      bytesCopied += bytesRead;
+    }
+    return bytesCopied;
   }
 
   /**
-   * Creates a {@link ZipCombiner} for combining ZIP files using the specified destination
-   * {@link OutputStream}. Uses the DONT_CARE {@link OutputMode} and a {@link CopyEntryFilter} as
-   * the {@link ZipEntryFilter}.
+   * Returns a 32-bit integer containing a ZIP-compatible encoding of the given
+   * date. Only dates between 1980 and 2107 (inclusive) are supported.
+   *
+   * <p>The upper 16 bits contain the year, month, and day. The lower 16 bits
+   * contain the hour, minute, and second. The resolution of the second field
+   * is only 4 bits, which means that the only even second values can be
+   * stored - this method rounds down to the nearest even value.
    *
-   * @param out the {@link OutputStream} for writing the combined ZIP file
+   * @throws IllegalArgumentException if the given date is outside the
+   *                                  supported range
    */
-  public ZipCombiner(OutputStream out) {
-    this(OutputMode.DONT_CARE, new CopyEntryFilter(), out);
+  // Only visible for testing.
+  static int dateToDosTime(Date date) {
+    Calendar calendar = new GregorianCalendar();
+    calendar.setTime(date);
+    int year = calendar.get(Calendar.YEAR);
+    if (year < 1980) {
+      throw new IllegalArgumentException("date must be in or after 1980");
+    }
+    // The ZIP format only provides 7 bits for the year.
+    if (year > 2107) {
+      throw new IllegalArgumentException("date must before 2107");
+    }
+    int month = calendar.get(Calendar.MONTH) + 1; // Months from Calendar are zero-based.
+    int day = calendar.get(Calendar.DAY_OF_MONTH);
+    int hour = calendar.get(Calendar.HOUR_OF_DAY);
+    int minute = calendar.get(Calendar.MINUTE);
+    int second = calendar.get(Calendar.SECOND);
+    return ((year - 1980) << 25) | (month << 21) | (day << 16)
+        | (hour << 11) | (minute << 5) | (second >> 1);
   }
 
   /**
-   * Write all contents from the {@link InputStream} as a prefix file for the combined ZIP file.
+   * Fills the directory entry, using the information from the header buffer,
+   * and writes it to the central directory. It returns the offset into the
+   * central directory that can be used for patching the entry. Requires that
+   * the entire entry header is present in {@link #headerBuffer}. It also uses
+   * the {@link ByteCountingOutputStream#bytesWritten}, so it must be called
+   * just before the header is written to the output stream.
    *
-   * @param in the {@link InputStream} containing the prefix file data
-   * @throws IOException if there is an error writing the prefix file
+   * @throws IOException if the current offset is too large for the ZIP format
+   */
+  private int fillDirectoryEntryBuffer(
+      DirectoryEntryInfo directoryEntryInfo) throws IOException {
+    // central file header signature
+    setUnsignedInt(directoryEntryBuffer, 0, CENTRAL_DIRECTORY_MARKER);
+    short version = (short) getUnsignedShort(headerBuffer, VERSION_TO_EXTRACT_OFFSET);
+    short curMadeMyVersion = (directoryEntryInfo.madeByVersion == -1)
+        ? version : directoryEntryInfo.madeByVersion;
+    setUnsignedShort(directoryEntryBuffer, 4, curMadeMyVersion); // version made by
+    // version needed to extract
+    setUnsignedShort(directoryEntryBuffer, 6, version);
+    // general purpose bit flag
+    setUnsignedShort(directoryEntryBuffer, 8,
+        (short) getUnsignedShort(headerBuffer, GENERAL_PURPOSE_FLAGS_OFFSET));
+    // compression method
+    setUnsignedShort(directoryEntryBuffer, 10,
+        (short) getUnsignedShort(headerBuffer, COMPRESSION_METHOD_OFFSET));
+    // last mod file time, last mod file date
+    setUnsignedShort(directoryEntryBuffer, 12,
+        (short) getUnsignedShort(headerBuffer, MTIME_OFFSET));
+    setUnsignedShort(directoryEntryBuffer, 14,
+        (short) getUnsignedShort(headerBuffer, MDATE_OFFSET));
+    // crc-32
+    setUnsignedInt(directoryEntryBuffer, 16, (int) getUnsignedInt(headerBuffer, CRC32_OFFSET));
+    // compressed size
+    setUnsignedInt(directoryEntryBuffer, 20,
+        (int) getUnsignedInt(headerBuffer, COMPRESSED_SIZE_OFFSET));
+    // uncompressed size
+    setUnsignedInt(directoryEntryBuffer, 24,
+        (int) getUnsignedInt(headerBuffer, UNCOMPRESSED_SIZE_OFFSET));
+    // file name length
+    setUnsignedShort(directoryEntryBuffer, 28,
+        (short) getUnsignedShort(headerBuffer, FILENAME_LENGTH_OFFSET));
+    // extra field length
+    setUnsignedShort(directoryEntryBuffer, 30,
+        (short) getUnsignedShort(headerBuffer, EXTRA_LENGTH_OFFSET));
+    setUnsignedShort(directoryEntryBuffer, 32, (short) 0); // file comment length
+    setUnsignedShort(directoryEntryBuffer, 34, (short) 0); // disk number start
+    setUnsignedShort(directoryEntryBuffer, 36, (short) 0); // internal file attributes
+    setUnsignedInt(directoryEntryBuffer, 38, directoryEntryInfo.externalFileAttribute);
+    if (out.bytesWritten >= MAXIMUM_DATA_SIZE) {
+      throw new IOException("Unable to handle files bigger than 2^32 bytes.");
+    }
+    // relative offset of local header
+    setUnsignedInt(directoryEntryBuffer, 42, (int) out.bytesWritten);
+    fileCount++;
+    return centralDirectory.writeToCentralDirectory(directoryEntryBuffer);
+  }
+
+  /**
+   * Fix the directory entry with the correct crc32, compressed size, and
+   * uncompressed size.
    */
-  public void prependExecutable(InputStream in) throws IOException {
-    out.startPrefixFile();
-    copyStream(in, out);
-    out.endPrefixFile();
+  private void fixDirectoryEntry(int offset, long crc32, long compressedSize,
+      long uncompressedSize) {
+    // The constants from the top don't apply here, because this is the central directory entry.
+    centralDirectory.setUnsignedInt(offset + 16, (int) crc32); // crc-32
+    centralDirectory.setUnsignedInt(offset + 20, (int) compressedSize); // compressed size
+    centralDirectory.setUnsignedInt(offset + 24, (int) uncompressedSize); // uncompressed size
   }
 
   /**
-   * Adds a directory entry to the combined ZIP file using the specified filename and date.
+   * (Un)Compresses and copies the current ZIP file entry. Requires that the
+   * entire entry header is present in {@link #headerBuffer}. It currently
+   * drops the extra data in the process.
    *
-   * @param filename the name of the directory to create
-   * @param date the modified time to assign to the directory
-   * @throws IOException if there is an error writing the directory entry
+   * @throws IOException if the underlying stream throws an IOException
    */
-  public void addDirectory(String filename, Date date) throws IOException {
-    addDirectory(filename, date, new ExtraData[0]);
+  private void modifyAndCopyEntry(String filename, InputStream in, int dosTime)
+      throws IOException {
+    final int method = getUnsignedShort(headerBuffer, COMPRESSION_METHOD_OFFSET);
+    final int flags = getUnsignedShort(headerBuffer, GENERAL_PURPOSE_FLAGS_OFFSET);
+    final int fileNameLength = getUnsignedShort(headerBuffer, FILENAME_LENGTH_OFFSET);
+    final int extraFieldLength = getUnsignedShort(headerBuffer, EXTRA_LENGTH_OFFSET);
+    // TODO(bazel-team): Read and copy the extra data if present.
+
+    forkOrSkipData(in, fileNameLength, SkipMode.SKIP);
+    forkOrSkipData(in, extraFieldLength, SkipMode.SKIP);
+    if (method == STORED_METHOD) {
+      long compressedSize = getUnsignedInt(headerBuffer, COMPRESSED_SIZE_OFFSET);
+      copyStreamToEntry(filename, new FixedLengthInputStream(in, compressedSize), dosTime,
+          NO_EXTRA_ENTRIES, true, DEFAULT_DIRECTORY_ENTRY_INFO);
+    } else if (method == DEFLATE_METHOD) {
+      inflater.reset();
+      copyStreamToEntry(filename, new DeflateInputStream(in), dosTime, NO_EXTRA_ENTRIES, false,
+          DEFAULT_DIRECTORY_ENTRY_INFO);
+      if ((flags & SIZE_MASKED_FLAG) != 0) {
+        copyOrSkipData(in, 16, SkipMode.SKIP);
+      }
+    } else {
+      throw new AssertionError("This should have been checked in validateHeader().");
+    }
   }
 
   /**
-   * Adds a directory entry to the combined ZIP file using the specified filename, date, and extra
-   * data.
+   * Copies or skips the current ZIP file entry. Requires that the entire entry
+   * header is present in {@link #headerBuffer}. It uses the current mode to
+   * decide whether to compress or decompress the entry.
    *
-   * @param filename the name of the directory to create
-   * @param date the modified time to assign to the directory
-   * @param extra the extra field data to add to the directory entry
-   * @throws IOException if there is an error writing the directory entry
+   * @throws IOException if the underlying stream throws an IOException
    */
-  public void addDirectory(String filename, Date date, ExtraData[] extra) throws IOException {
-    checkArgument(filename.endsWith("/"), "Directory names must end with a /");
-    checkState(!entries.containsKey(filename),
-        "Zip already contains a directory named %s", filename);
+  private void copyOrSkipEntry(String filename, InputStream in, SkipMode skip, Date date,
+      DirectoryEntryInfo directoryEntryInfo) throws IOException {
+    copyOrSkipEntry(filename, in, skip, date, directoryEntryInfo, false);
+  }
 
-    ZipFileEntry entry = new ZipFileEntry(filename);
-    entry.setMethod(Compression.STORED);
-    entry.setCrc(0);
-    entry.setSize(0);
-    entry.setCompressedSize(0);
-    entry.setTime(date != null ? date.getTime() : new Date().getTime());
-    entry.setExtra(extra);
-    out.putNextEntry(entry);
-    out.closeEntry();
-    entries.put(filename, entry);
+  /**
+   * Renames and otherwise copies the current ZIP file entry. Requires that the entire
+   * entry header is present in {@link #headerBuffer}. It uses the current mode to
+   * decide whether to compress or decompress the entry.
+   *
+   * @throws IOException if the underlying stream throws an IOException
+   */
+  private void renameEntry(String filename, InputStream in, Date date,
+      DirectoryEntryInfo directoryEntryInfo) throws IOException {
+    copyOrSkipEntry(filename, in, SkipMode.COPY, date, directoryEntryInfo, true);
   }
 
   /**
-   * Adds a file with the specified name to the combined ZIP file.
+   * Copies or skips the current ZIP file entry. Requires that the entire entry
+   * header is present in {@link #headerBuffer}. It uses the current mode to
+   * decide whether to compress or decompress the entry.
    *
-   * @param filename the name of the file to create
-   * @param in the {@link InputStream} containing the file data
-   * @throws IOException if there is an error writing the file entry
-   * @throws IllegalArgumentException if the combined ZIP file already contains a file of the same
-   *     name.
+   * @throws IOException if the underlying stream throws an IOException
    */
-  public void addFile(String filename, InputStream in) throws IOException {
-    addFile(filename, null, in);
+  private void copyOrSkipEntry(String filename, InputStream in, SkipMode skip, Date date,
+      DirectoryEntryInfo directoryEntryInfo, boolean rename) throws IOException {
+    final int method = getUnsignedShort(headerBuffer, COMPRESSION_METHOD_OFFSET);
+
+    // We can cast here, because the result is only treated as a bitmask.
+    int dosTime = date == null ? (int) getUnsignedInt(headerBuffer, MTIME_OFFSET)
+        : dateToDosTime(date);
+    if (skip == SkipMode.COPY) {
+      if ((mode == OutputMode.FORCE_DEFLATE) && (method == STORED_METHOD)
+          && !filename.endsWith("/")) {
+        modifyAndCopyEntry(filename, in, dosTime);
+        return;
+      } else if ((mode == OutputMode.FORCE_STORED) && (method == DEFLATE_METHOD)) {
+        modifyAndCopyEntry(filename, in, dosTime);
+        return;
+      }
+    }
+
+    int directoryOffset = copyOrSkipEntryHeader(filename, in, date, directoryEntryInfo,
+        skip, rename);
+
+    copyOrSkipEntryData(filename, in, skip, directoryOffset);
   }
 
   /**
-   * Adds a file with the specified name and date to the combined ZIP file.
+   * Copies or skips the header of an entry, including filename and extra data.
+   * Requires that the entire entry header is present in {@link #headerBuffer}.
    *
-   * @param filename the name of the file to create
-   * @param date the modified time to assign to the file
-   * @param in the {@link InputStream} containing the file data
-   * @throws IOException if there is an error writing the file entry
-   * @throws IllegalArgumentException if the combined ZIP file already contains a file of the same
-   *     name.
+   * @returns the enrty offset in the central directory
+   * @throws IOException if the underlying stream throws an IOException
    */
-  public void addFile(String filename, Date date, InputStream in) throws IOException {
-    ZipFileEntry entry = new ZipFileEntry(filename);
-    entry.setTime(date != null ? date.getTime() : new Date().getTime());
-    addFile(entry, in);
+  private int copyOrSkipEntryHeader(String filename, InputStream in, Date date,
+      DirectoryEntryInfo directoryEntryInfo, SkipMode skip, boolean rename)
+      throws IOException {
+    final int fileNameLength = getUnsignedShort(headerBuffer, FILENAME_LENGTH_OFFSET);
+    final int extraFieldLength = getUnsignedShort(headerBuffer, EXTRA_LENGTH_OFFSET);
+
+    byte[] fileNameAsBytes = null;
+    if (rename) {
+      // If the entry is renamed, we patch the filename length in the buffer
+      // before it's copied, and before writing to the central directory.
+      fileNameAsBytes = filename.getBytes(UTF_8);
+      checkArgument(fileNameAsBytes.length <= 65535,
+          "File name too long: %s bytes (max. 65535)", fileNameAsBytes.length);
+      setUnsignedShort(headerBuffer, FILENAME_LENGTH_OFFSET, (short) fileNameAsBytes.length);
+    }
+
+    int directoryOffset = 0;
+    if (skip == SkipMode.COPY) {
+      if (date != null) {
+        int dosTime = dateToDosTime(date);
+        setUnsignedShort(headerBuffer, MTIME_OFFSET, (short) dosTime); // lower 16 bits
+        setUnsignedShort(headerBuffer, MDATE_OFFSET, (short) (dosTime >> 16)); // upper 16 bits
+      }
+      // Call this before writing the data out, so that we get the correct offset.
+      directoryOffset = fillDirectoryEntryBuffer(directoryEntryInfo);
+      write(headerBuffer, 0, FILE_HEADER_BUFFER_SIZE);
+    }
+    if (!rename) {
+      forkOrSkipData(in, fileNameLength, skip);
+    } else {
+      forkOrSkipData(in, fileNameLength, SkipMode.SKIP);
+      write(fileNameAsBytes);
+      centralDirectory.writeToCentralDirectory(fileNameAsBytes);
+    }
+    forkOrSkipData(in, extraFieldLength, skip);
+    return directoryOffset;
   }
 
   /**
-   * Adds a file with attributes specified by the {@link ZipFileEntry} to the combined ZIP file.
+   * Copy or skip the data of an entry. Requires that the
+   * entire entry header is present in {@link #headerBuffer}.
    *
-   * @param entry the {@link ZipFileEntry} containing the entry meta-data
-   * @param in the {@link InputStream} containing the file data
-   * @throws IOException if there is an error writing the file entry
-   * @throws IllegalArgumentException if the combined ZIP file already contains a file of the same
-   *     name.
+   * @throws IOException if the underlying stream throws an IOException
+   */
+  private void copyOrSkipEntryData(String filename, InputStream in, SkipMode skip,
+      int directoryOffset) throws IOException {
+    final int flags = getUnsignedShort(headerBuffer, GENERAL_PURPOSE_FLAGS_OFFSET);
+    final int method = getUnsignedShort(headerBuffer, COMPRESSION_METHOD_OFFSET);
+    if ((flags & SIZE_MASKED_FLAG) != 0) {
+      // The compressed data size is unknown.
+      if (method != DEFLATE_METHOD) {
+        throw new AssertionError("This should have been checked in validateHeader().");
+      }
+      copyOrSkipDeflateData(in, skip);
+      // The flags indicate that a data descriptor must follow the data.
+      readFully(in, 16);
+      if (getUnsignedInt(buffer, bufferOffset) != DATA_DESCRIPTOR_MARKER) {
+        throw new IOException("Missing data descriptor for " + filename + " in " + currentInputFile
+            + ".");
+      }
+      long crc32 = getUnsignedInt(buffer, bufferOffset + 4);
+      long compressedSize = getUnsignedInt(buffer, bufferOffset + 8);
+      long uncompressedSize = getUnsignedInt(buffer, bufferOffset + 12);
+      if (skip == SkipMode.COPY) {
+        fixDirectoryEntry(directoryOffset, crc32, compressedSize, uncompressedSize);
+      }
+      copyOrSkipData(in, 16, skip);
+    } else {
+      // The size value is present in the header, so just copy that amount.
+      long compressedSize = getUnsignedInt(headerBuffer, COMPRESSED_SIZE_OFFSET);
+      copyOrSkipData(in, compressedSize, skip);
+    }
+  }
+
+  /**
+   * An input stream that reads a fixed number of bytes from the given input
+   * stream before it returns end-of-input. It uses the local buffer, so it
+   * can't be static.
    */
-  public void addFile(ZipFileEntry entry, InputStream in) throws IOException {
-    checkNotNull(entry, "Zip entry must not be null.");
-    checkNotNull(in, "Input stream must not be null.");
-    checkArgument(!entries.containsKey(entry.getName()), "Zip already contains a file named '%s'.",
-        entry.getName());
+  private class FixedLengthInputStream extends InputStream {
+
+    private final InputStream in;
+    private long remainingBytes;
+    private final byte[] singleByteBuffer = new byte[1];
 
-    ByteArrayOutputStream uncompressed = new ByteArrayOutputStream();
-    copyStream(in, uncompressed);
+    FixedLengthInputStream(InputStream in, long remainingBytes) {
+      this.in = in;
+      this.remainingBytes = remainingBytes;
+    }
 
-    writeEntryFromBuffer(new ZipFileEntry(entry), uncompressed.toByteArray());
+    @Override
+    public int read() throws IOException {
+      int bytesRead = read(singleByteBuffer, 0, 1);
+      return (bytesRead == -1) ? -1 : singleByteBuffer[0];
+    }
+
+    @Override
+    public int read(byte b[], int off, int len) throws IOException {
+      checkArgument(len >= 0);
+      checkArgument(off >= 0);
+      checkArgument(off + len <= b.length);
+      if (remainingBytes == 0) {
+        return -1;
+      }
+      if (bufferLength == 0) {
+        readMoreData(in);
+      }
+      int bytesToCopy = len;
+      if (remainingBytes < bytesToCopy) {
+        bytesToCopy = (int) remainingBytes;
+      }
+      if (bufferLength < bytesToCopy) {
+        bytesToCopy = bufferLength;
+      }
+      System.arraycopy(buffer, bufferOffset, b, off, bytesToCopy);
+      bufferOffset += bytesToCopy;
+      bufferLength -= bytesToCopy;
+      remainingBytes -= bytesToCopy;
+      return bytesToCopy;
+    }
   }
 
   /**
-   * Adds the contents of a ZIP file to the combined ZIP file using the specified
-   * {@link ZipEntryFilter} to determine the appropriate action for each file. 
+   * An input stream that reads from a given input stream, decoding that data
+   * according to the DEFLATE algorithm. The DEFLATE data stream implicitly
+   * contains its own end-of-input marker. It uses the local buffer, so it
+   * can't be static.
+   */
+  private class DeflateInputStream extends InputStream {
+
+    private final InputStream in;
+    private final byte[] singleByteBuffer = new byte[1];
+    private final MutableInt consumedBytes = new MutableInt(0);
+
+    DeflateInputStream(InputStream in) {
+      this.in = in;
+    }
+
+    @Override
+    public int read() throws IOException {
+      int bytesRead = read(singleByteBuffer, 0, 1);
+      // Do an unsigned cast on the byte from the buffer if it exists.
+      return (bytesRead == -1) ? -1 : (singleByteBuffer[0] & 0xff);
+    }
+
+    @Override
+    public int read(byte b[], int off, int len) throws IOException {
+      if (inflater.finished()) {
+        return -1;
+      }
+      int length = inflateData(in, b, off, len, consumedBytes);
+      int bytesRead = consumedBytes.getValue();
+      bufferOffset += bytesRead;
+      bufferLength -= bytesRead;
+      return length == 0 ? -1 : length;
+    }
+  }
+
+  /**
+   * Handles a custom merge operation with the given strategy. This method
+   * creates an appropriate input stream and hands it to the strategy for
+   * processing. Requires that the entire entry header is present in {@link
+   * #headerBuffer}.
    *
-   * @param in the InputStream of the ZIP file to add to the combined ZIP file
-   * @throws IOException if there is an error reading the ZIP file or writing entries to the
-   *     combined ZIP file
+   * @throws IOException if one of the underlying stream throws an IOException,
+   *                     if the ZIP entry data is inconsistent, or if the
+   *                     implementation cannot handle the compression method
+   *                     given in the ZIP entry
    */
-  @Deprecated
-  public void addZip(InputStream in) throws IOException {
-    File file = Files.createTempFile(null, null).toFile();
-    Files.copy(in, file.toPath(), StandardCopyOption.REPLACE_EXISTING);
-    addZip(file);
-    file.deleteOnExit();
-  }
-
-  /**
-   * Adds the contents of a ZIP file to the combined ZIP file using the specified
-   * {@link ZipEntryFilter} to determine the appropriate action for each file. 
-   *
-   * @param zipFile the ZIP file to add to the combined ZIP file
-   * @throws IOException if there is an error reading the ZIP file or writing entries to the
-   *     combined ZIP file
-   */
-  public void addZip(File zipFile) throws IOException {
-    try (ZipReader zip = new ZipReader(zipFile)) {
-      for (ZipFileEntry entry : zip.entries()) {
-        String filename = entry.getName();
-        EntryAction action = getAction(filename);
-        switch (action.getType()) {
-          case SKIP:
-            break;
-          case COPY:
-          case RENAME:
-            writeEntry(zip, entry, action);
-            break;
-          case MERGE:
-            entries.put(filename, null);
-            InputStream in = zip.getRawInputStream(entry);
-            if (entry.getMethod() == Compression.DEFLATED) {
-              in = new InflaterInputStream(in, getInflater());
-            }
-            action.getStrategy().merge(in, action.getMergeBuffer());
-            break;
-        }
+  private void handleCustomMerge(final InputStream in, CustomMergeStrategy mergeStrategy,
+      ByteArrayOutputStream outputBuffer) throws IOException {
+    final int flags = getUnsignedShort(headerBuffer, GENERAL_PURPOSE_FLAGS_OFFSET);
+    final int method = getUnsignedShort(headerBuffer, COMPRESSION_METHOD_OFFSET);
+    final long compressedSize = getUnsignedInt(headerBuffer, COMPRESSED_SIZE_OFFSET);
+
+    final int fileNameLength = getUnsignedShort(headerBuffer, FILENAME_LENGTH_OFFSET);
+    final int extraFieldLength = getUnsignedShort(headerBuffer, EXTRA_LENGTH_OFFSET);
+
+    copyOrSkipData(in, fileNameLength, SkipMode.SKIP);
+    copyOrSkipData(in, extraFieldLength, SkipMode.SKIP);
+    if (method == STORED_METHOD) {
+      mergeStrategy.merge(new FixedLengthInputStream(in, compressedSize), outputBuffer);
+    } else if (method == DEFLATE_METHOD) {
+      inflater.reset();
+      // TODO(bazel-team): Defend against the mergeStrategy not reading the complete input.
+      mergeStrategy.merge(new DeflateInputStream(in), outputBuffer);
+      if ((flags & SIZE_MASKED_FLAG) != 0) {
+        copyOrSkipData(in, 16, SkipMode.SKIP);
       }
+    } else {
+      throw new AssertionError("This should have been checked in validateHeader().");
     }
   }
 
-  /** Returns the action to take for a file of the given filename. */
-  private EntryAction getAction(String filename) throws IOException {
-    // If this filename has not been encountered before (no entry for filename) or this filename
-    // has been renamed (RENAME entry for filename), the desired action should be recomputed.
-    if (!actions.containsKey(filename) || actions.get(filename).getType() == ActionType.RENAME) {
-      callback.resetForFile(filename);
-      entryFilter.accept(filename, callback);
+  /**
+   * Implementation of the strategy callback.
+   */
+  private class TheStrategyCallback implements StrategyCallback {
+
+    private String filename;
+    private final InputStream in;
+
+    // Use an atomic boolean to make sure that only a single call goes
+    // through, even if there are multiple concurrent calls. Paranoid
+    // defensive programming.
+    private final AtomicBoolean callDone = new AtomicBoolean();
+
+    TheStrategyCallback(String filename, InputStream in) {
+      this.filename = filename;
+      this.in = in;
     }
-    checkState(actions.containsKey(filename),
-        "Action for file '%s' should have been set by ZipEntryFilter.", filename);
 
-    EntryAction action = actions.get(filename);
-    // Only copy if this is the first instance of filename.
-    if (action.getType() == ActionType.COPY && entries.containsKey(filename)) {
-      action = new EntryAction(ActionType.SKIP, action);
-      actions.put(filename, action);
+    // Verify that this is the first call and throw an exception if not.
+    private void checkCall() {
+      checkState(callDone.compareAndSet(false, true), "The callback was already called once.");
     }
-    // Only rename if there is not already an entry with filename or filename's action is SKIP.
-    if (action.getType() == ActionType.RENAME) {
-      if (actions.containsKey(action.getNewName())
-          && actions.get(action.getNewName()).getType() == ActionType.SKIP) {
-        action = new EntryAction(ActionType.SKIP, action);
+
+    @Override
+    public void copy(Date date) throws IOException {
+      checkCall();
+      if (!containsFile(filename)) {
+        fileNames.put(filename, COPIED_FILE_ENTRY);
+        copyOrSkipEntry(filename, in, SkipMode.COPY, date, DEFAULT_DIRECTORY_ENTRY_INFO);
+      } else { // can't copy, name already used for renamed entry
+        copyOrSkipEntry(filename, in, SkipMode.SKIP, null, DEFAULT_DIRECTORY_ENTRY_INFO);
       }
-      if (entries.containsKey(action.getNewName())) {
-        action = new EntryAction(ActionType.SKIP, action);
+    }
+
+    @Override
+    public void rename(String newName, Date date) throws IOException {
+      checkCall();
+      if (!containsFile(newName)) {
+        fileNames.put(newName, RENAMED_FILE_ENTRY);
+        renameEntry(newName, in, date, DEFAULT_DIRECTORY_ENTRY_INFO);
+      } else {
+        copyOrSkipEntry(filename, in, SkipMode.SKIP, null, DEFAULT_DIRECTORY_ENTRY_INFO);
+      }
+      filename = newName;
+    }
+
+    @Override
+    public void skip() throws IOException {
+      checkCall();
+      if (!containsFile(filename)) {// don't overwrite possible RENAMED_FILE_ENTRY value
+        fileNames.put(filename, COPIED_FILE_ENTRY);
       }
+      copyOrSkipEntry(filename, in, SkipMode.SKIP, null, DEFAULT_DIRECTORY_ENTRY_INFO);
+    }
+
+    @Override
+    public void customMerge(Date date, CustomMergeStrategy strategy) throws IOException {
+      checkCall();
+      ByteArrayOutputStream outputBuffer = new ByteArrayOutputStream();
+      fileNames.put(filename, new FileEntry(strategy, outputBuffer, dateToDosTime(date)));
+      handleCustomMerge(in, strategy, outputBuffer);
+    }
+  }
+
+  /**
+   * Validates that the current entry obeys all the restrictions of this implementation.
+   *
+   * @throws IOException if the current entry doesn't obey the restrictions
+   */
+  private void validateHeader() throws IOException {
+    // We only handle DEFLATE and STORED, like java.util.zip.
+    final int method = getUnsignedShort(headerBuffer, COMPRESSION_METHOD_OFFSET);
+    if ((method != DEFLATE_METHOD) && (method != STORED_METHOD)) {
+      throw new IOException("Unable to handle compression methods other than DEFLATE!");
+    }
+
+    // If the method is STORED, then the size must be available in the header.
+    final int flags = getUnsignedShort(headerBuffer, GENERAL_PURPOSE_FLAGS_OFFSET);
+    if ((method == STORED_METHOD) && ((flags & SIZE_MASKED_FLAG) != 0)) {
+      throw new IOException("If the method is STORED, then the size must be available in the"
+          + " header!");
+    }
+
+    // If the method is STORED, the compressed and uncompressed sizes must be equal.
+    final long compressedSize = getUnsignedInt(headerBuffer, COMPRESSED_SIZE_OFFSET);
+    final long uncompressedSize = getUnsignedInt(headerBuffer, UNCOMPRESSED_SIZE_OFFSET);
+    if ((method == STORED_METHOD) && (compressedSize != uncompressedSize)) {
+      throw new IOException("Compressed and uncompressed sizes for STORED entry differ!");
+    }
+
+    // The compressed or uncompressed size being set to 0xffffffff is a strong indicator that the
+    // ZIP file is in ZIP64 mode, which supports files larger than 2^32.
+    // TODO(bazel-team): Support the ZIP64 extension.
+    if ((compressedSize == MAXIMUM_DATA_SIZE) || (uncompressedSize == MAXIMUM_DATA_SIZE)) {
+      throw new IOException("Unable to handle ZIP64 compressed files.");
     }
-    return action;
   }
 
-  /** Writes an entry with the given name, date and external file attributes from the buffer. */
-  private void writeEntryFromBuffer(ZipFileEntry entry, byte[] uncompressed) throws IOException {
-    CRC32 crc = new CRC32();
-    crc.update(uncompressed);
+  /**
+   * Reads a file entry from the input stream, calls the entryFilter to
+   * determine what to do with the entry, and performs the requested operation.
+   * Returns true if the input stream contained another entry.
+   *
+   * @throws IOException if one of the underlying stream throws an IOException,
+   *                     if the ZIP contains unsupported, inconsistent or
+   *                     incomplete data or if the filter throws an IOException
+   */
+  private boolean handleNextEntry(final InputStream in) throws IOException {
+    // Just try to read the complete header and fail if it didn't work.
+    try {
+      readFully(in, FILE_HEADER_BUFFER_SIZE);
+    } catch (EOFException e) {
+      return false;
+    }
+
+    System.arraycopy(buffer, bufferOffset, headerBuffer, 0, FILE_HEADER_BUFFER_SIZE);
+    bufferOffset += FILE_HEADER_BUFFER_SIZE;
+    bufferLength -= FILE_HEADER_BUFFER_SIZE;
+    if (getUnsignedInt(headerBuffer, 0) != LOCAL_FILE_HEADER_MARKER) {
+      return false;
+    }
+    validateHeader();
 
-    entry.setCrc(crc.getValue());
-    entry.setSize(uncompressed.length);
-    if (mode == OutputMode.FORCE_STORED) {
-      entry.setMethod(Compression.STORED);
-      entry.setCompressedSize(uncompressed.length);
-      writeEntry(entry, new ByteArrayInputStream(uncompressed));
+    final int fileNameLength = getUnsignedShort(headerBuffer, FILENAME_LENGTH_OFFSET);
+    readFully(in, fileNameLength);
+    // TODO(bazel-team): If I read the spec correctly, this should be UTF-8 rather than ISO-8859-1.
+    final String filename = new String(buffer, bufferOffset, fileNameLength, ISO_8859_1);
+
+    FileEntry handler = fileNames.get(filename);
+    // The handler is null if this is the first time we see an entry with this filename,
+    // or if all previous entries with this name were renamed by the filter (and we can
+    // pretend we didn't encounter the name yet).
+    // If the handler is RENAMED_FILE_ENTRY, a previous entry was renamed as filename,
+    // in which case the filter should now be invoked for this name for the first time,
+    // giving the filter a chance to choose an unique name.
+    if (handler == null || handler == RENAMED_FILE_ENTRY) {
+      TheStrategyCallback callback = new TheStrategyCallback(filename, in);
+      entryFilter.accept(filename, callback);
+      if (fileNames.get(callback.filename) == null && fileNames.get(filename) == null) {
+        throw new IllegalStateException();
+      }
+    } else if (handler.mergeStrategy == null) {
+      copyOrSkipEntry(filename, in, SkipMode.SKIP, null, DEFAULT_DIRECTORY_ENTRY_INFO);
     } else {
-      ByteArrayOutputStream compressed = new ByteArrayOutputStream();
-      copyStream(new DeflaterInputStream(new ByteArrayInputStream(uncompressed), getDeflater()),
-          compressed);
-      entry.setMethod(Compression.DEFLATED);
-      entry.setCompressedSize(compressed.size());
-      writeEntry(entry, new ByteArrayInputStream(compressed.toByteArray()));
+      handleCustomMerge(in, handler.mergeStrategy, handler.outputBuffer);
     }
+    return true;
   }
 
   /**
-   * Writes an entry from the specified source {@link ZipReader} and {@link ZipFileEntry} using the
-   * specified {@link EntryAction}.
-   * 
-   *  <p>Writes the output entry from the input entry performing inflation or deflation as needed
-   *  and applies any values from the {@link EntryAction} as needed.
+   * Clears the internal buffer.
    */
-  private void writeEntry(ZipReader zip, ZipFileEntry entry, EntryAction action)
+  private void clearBuffer() {
+    bufferOffset = 0;
+    bufferLength = 0;
+  }
+
+  /**
+   * Copies another ZIP file into the output. If multiple entries with the same
+   * name are present, the first such entry is copied, but the others are
+   * ignored. This is also true for multiple invocations of this method. The
+   * {@code inputName} parameter is used to provide better error messages in the
+   * case of a failure to decode the ZIP file.
+   *
+   * @throws IOException if one of the underlying stream throws an IOException,
+   *                     if the ZIP contains unsupported, inconsistent or
+   *                     incomplete data or if the filter throws an IOException
+   */
+  public void addZip(String inputName, InputStream in) throws IOException {
+    if (finished) {
+      throw new IllegalStateException();
+    }
+    if (in == null) {
+      throw new NullPointerException();
+    }
+    clearBuffer();
+    currentInputFile = inputName;
+    while (handleNextEntry(in)) {/*handleNextEntry has side-effect.*/}
+  }
+
+  public void addZip(InputStream in) throws IOException {
+    addZip(null, in);
+  }
+
+  private void copyStreamToEntry(String filename, InputStream in, int dosTime,
+      ExtraData[] extraDataEntries, boolean compress, DirectoryEntryInfo directoryEntryInfo)
       throws IOException {
-    checkArgument(action.getType() != ActionType.SKIP,
-        "Cannot write a zip entry whose action is of type SKIP.");
-
-    ZipFileEntry outEntry = new ZipFileEntry(entry);
-    if (action.getType() == ActionType.RENAME) {
-      checkNotNull(action.getNewName(),
-          "ZipEntryFilter actions of type RENAME must not have a null filename.");
-      outEntry.setName(action.getNewName());
-    }
-
-    if (action.getDate() != null) {
-      outEntry.setTime(action.getDate().getTime());
-    }
-
-    InputStream data;
-    if (mode == OutputMode.FORCE_DEFLATE && entry.getMethod() != Compression.DEFLATED) {
-      // The output mode is deflate, but the entry compression is not. Create a deflater stream
-      // from the raw file data and deflate to a temporary byte array to determine the deflated
-      // size. Then use this byte array as the input stream for writing the entry.
-      ByteArrayOutputStream tmp = new ByteArrayOutputStream();
-      copyStream(new DeflaterInputStream(zip.getRawInputStream(entry), getDeflater()), tmp);
-      data = new ByteArrayInputStream(tmp.toByteArray());
-      outEntry.setMethod(Compression.DEFLATED);
-      outEntry.setCompressedSize(tmp.size());
-    } else if (mode == OutputMode.FORCE_STORED && entry.getMethod() != Compression.STORED) {
-      // The output mode is stored, but the entry compression is not; create an inflater stream
-      // from the raw file data. 
-      data = new InflaterInputStream(zip.getRawInputStream(entry), getInflater());
-      outEntry.setMethod(Compression.STORED);
-      outEntry.setCompressedSize(entry.getSize());
+    fileNames.put(filename, COPIED_FILE_ENTRY);
+
+    byte[] fileNameAsBytes = filename.getBytes(UTF_8);
+    checkArgument(fileNameAsBytes.length <= 65535,
+        "File name too long: %s bytes (max. 65535)", fileNameAsBytes.length);
+
+    // Note: This method can be called with an input stream that uses the buffer field of this
+    // class. We use a local buffer here to avoid conflicts.
+    byte[] localBuffer = new byte[4096];
+
+    byte[] uncompressedData = null;
+    if (!compress) {
+      ByteArrayOutputStream temp = new ByteArrayOutputStream();
+      int bytesRead;
+      while ((bytesRead = in.read(localBuffer)) != -1) {
+        temp.write(localBuffer, 0, bytesRead);
+      }
+      uncompressedData = temp.toByteArray();
+    }
+    byte[] extraData = null;
+    if (extraDataEntries.length != 0) {
+      int totalLength = 0;
+      for (ExtraData extra : extraDataEntries) {
+        int length = extra.getData().length;
+        if (totalLength > 0xffff - 4 - length) {
+          throw new IOException("Total length of extra data too big.");
+        }
+        totalLength += length + 4;
+      }
+      extraData = new byte[totalLength];
+      int position = 0;
+      for (ExtraData extra : extraDataEntries) {
+        byte[] data = extra.getData();
+        setUnsignedShort(extraData, position + 0, extra.getId());
+        setUnsignedShort(extraData, position + 2, (short) data.length);
+        System.arraycopy(data, 0, extraData, position + 4, data.length);
+        position += data.length + 4;
+      }
+    }
+
+    // write header
+    Arrays.fill(headerBuffer, (byte) 0);
+    setUnsignedInt(headerBuffer, 0, LOCAL_FILE_HEADER_MARKER); // file header signature
+    if (compress) {
+      setUnsignedShort(headerBuffer, 4, (short) VERSION_DEFLATE); // version to extract
+      setUnsignedShort(headerBuffer, 6, (short) SIZE_MASKED_FLAG); // general purpose bit flag
+      setUnsignedShort(headerBuffer, 8, (short) DEFLATE_METHOD); // compression method
+    } else {
+      setUnsignedShort(headerBuffer, 4, (short) VERSION_STORED); // version to extract
+      setUnsignedShort(headerBuffer, 6, (short) 0); // general purpose bit flag
+      setUnsignedShort(headerBuffer, 8, (short) STORED_METHOD); // compression method
+    }
+    setUnsignedShort(headerBuffer, 10, (short) dosTime); // mtime
+    setUnsignedShort(headerBuffer, 12, (short) (dosTime >> 16)); // mdate
+    if (uncompressedData != null) {
+      CRC32 crc = new CRC32();
+      crc.update(uncompressedData);
+      setUnsignedInt(headerBuffer, 14, (int) crc.getValue()); // crc32
+      setUnsignedInt(headerBuffer, 18, uncompressedData.length); // compressed size
+      setUnsignedInt(headerBuffer, 22, uncompressedData.length); // uncompressed size
+    } else {
+      setUnsignedInt(headerBuffer, 14, 0); // crc32
+      setUnsignedInt(headerBuffer, 18, 0); // compressed size
+      setUnsignedInt(headerBuffer, 22, 0); // uncompressed size
+    }
+    setUnsignedShort(headerBuffer, 26, (short) fileNameAsBytes.length); // file name length
+    if (extraData != null) {
+      setUnsignedShort(headerBuffer, 28, (short) extraData.length); // extra field length
+    } else {
+      setUnsignedShort(headerBuffer, 28, (short) 0); // extra field length
+    }
+
+    // This call works for both compressed or uncompressed entries.
+    int directoryOffset = fillDirectoryEntryBuffer(directoryEntryInfo);
+    write(headerBuffer);
+    write(fileNameAsBytes);
+    centralDirectory.writeToCentralDirectory(fileNameAsBytes);
+    if (extraData != null) {
+      write(extraData);
+      centralDirectory.writeToCentralDirectory(extraData);
+    }
+
+    // write data
+    if (uncompressedData != null) {
+      write(uncompressedData);
     } else {
-      // Entry compression agrees with output mode; use the raw file data as is.
-      data = zip.getRawInputStream(entry);
+      try (DeflaterOutputStream deflaterStream = new DeflaterOutputStream()) {
+        int bytesRead;
+        while ((bytesRead = in.read(localBuffer)) != -1) {
+          deflaterStream.write(localBuffer, 0, bytesRead);
+        }
+        deflaterStream.finish();
+
+        // write data descriptor
+        Arrays.fill(headerBuffer, (byte) 0);
+        setUnsignedInt(headerBuffer, 0, DATA_DESCRIPTOR_MARKER);
+        setUnsignedInt(headerBuffer, 4, deflaterStream.getCRC()); // crc32
+        setUnsignedInt(headerBuffer, 8, deflaterStream.getCompressedSize()); // compressed size
+        setUnsignedInt(headerBuffer, 12, deflaterStream.getUncompressedSize()); // uncompressed size
+        write(headerBuffer, 0, 16);
+        fixDirectoryEntry(directoryOffset, deflaterStream.getCRC(),
+            deflaterStream.getCompressedSize(), deflaterStream.getUncompressedSize());
+      }
     }
-    writeEntry(outEntry, data);
   }
 
   /**
-   * Writes the specified {@link ZipFileEntry} using the data from the given {@link InputStream}.
+   * Adds a new entry into the output, by reading the input stream until it
+   * returns end of stream. Equivalent to
+   * {@link #addFile(String, Date, InputStream, DirectoryEntryInfo)}, but uses
+   * {@link #DEFAULT_DIRECTORY_ENTRY_INFO} for the file's directory entry.
    */
-  private void writeEntry(ZipFileEntry entry, InputStream data) throws IOException {
-    out.putNextEntry(entry);
-    copyStream(data, out);
-    out.closeEntry();
-    entries.put(entry.getName(), entry);
+  public void addFile(String filename, Date date, InputStream in) throws IOException {
+    addFile(filename, date, in, DEFAULT_DIRECTORY_ENTRY_INFO);
   }
 
   /**
-   * Returns true if the combined ZIP file already contains a file of the specified file name.
+   * Adds a new entry into the output, by reading the input stream until it
+   * returns end of stream. This method does not call {@link
+   * ZipEntryFilter#accept}.
    *
-   * @param filename the filename of the file whose presence in the combined ZIP file is to be
-   *     tested
-   * @return true if the combined ZIP file contains the specified file
+   * @throws IOException if one of the underlying streams throws an IOException
+   *                     or if the input stream returns more data than
+   *                     supported by the ZIP format
+   * @throws IllegalStateException if an entry with the given name already
+   *                               exists
+   * @throws IllegalArgumentException if the given file name is longer than
+   *                                  supported by the ZIP format
    */
-  public boolean containsFile(String filename) {
-    // TODO(apell): may be slightly different behavior because v1 returns true on skipped names.
-    return entries.containsKey(filename);
+  public void addFile(String filename, Date date, InputStream in,
+      DirectoryEntryInfo directoryEntryInfo) throws IOException {
+    checkNotFinished();
+    if (in == null) {
+      throw new NullPointerException();
+    }
+    if (filename == null) {
+      throw new NullPointerException();
+    }
+    checkState(!fileNames.containsKey(filename),
+        "jar already contains a file named %s", filename);
+    int dosTime = dateToDosTime(date != null ? date : new Date());
+    copyStreamToEntry(filename, in, dosTime, NO_EXTRA_ENTRIES,
+        mode != OutputMode.FORCE_STORED, // Always compress if we're allowed to.
+        directoryEntryInfo);
+  }
+
+  /**
+   * Adds a new directory entry into the output. This method does not call
+   * {@link ZipEntryFilter#accept}. Uses {@link #DEFAULT_DIRECTORY_ENTRY_INFO} for the added
+   * directory entry.
+   *
+   * @throws IOException if one of the underlying streams throws an IOException
+   * @throws IllegalStateException if an entry with the given name already
+   *                               exists
+   * @throws IllegalArgumentException if the given file name is longer than
+   *                                  supported by the ZIP format
+   */
+  public void addDirectory(String filename, Date date, ExtraData[] extraDataEntries)
+      throws IOException {
+    checkNotFinished();
+    checkArgument(filename.endsWith("/")); // Can also throw NPE.
+    checkState(!fileNames.containsKey(filename),
+        "jar already contains a directory named %s", filename);
+    int dosTime = dateToDosTime(date != null ? date : new Date());
+    copyStreamToEntry(filename, new ByteArrayInputStream(new byte[0]), dosTime, extraDataEntries,
+        false, // Never compress directory entries.
+        DEFAULT_DIRECTORY_ENTRY_INFO);
   }
 
   /**
-   * Writes any remaining output data to the output stream and also creates the merged entries by
-   * calling the {@link CustomMergeStrategy} implementations given back from the
-   * {@link ZipEntryFilter}.
+   * Adds a new directory entry into the output. This method does not call
+   * {@link ZipEntryFilter#accept}.
    *
-   * @throws IOException if the output stream or the filter throws an IOException
+   * @throws IOException if one of the underlying streams throws an IOException
+   * @throws IllegalStateException if an entry with the given name already
+   *                               exists
+   * @throws IllegalArgumentException if the given file name is longer than
+   *                                  supported by the ZIP format
+   */
+  public void addDirectory(String filename, Date date)
+      throws IOException {
+    addDirectory(filename, date, NO_EXTRA_ENTRIES);
+  }
+
+  /**
+   * A deflater output stream that also counts uncompressed and compressed
+   * numbers of bytes and computes the CRC so that the data descriptor marker
+   * is written correctly.
+   *
+   * <p>Not static, so it can access the write() methods.
+   */
+  private class DeflaterOutputStream extends OutputStream {
+
+    private final Deflater deflater = new Deflater(Deflater.DEFAULT_COMPRESSION, true);
+    private final CRC32 crc = new CRC32();
+    private final byte[] outputBuffer = new byte[4096];
+    private long uncompressedBytes = 0;
+    private long compressedBytes = 0;
+
+    @Override
+    public void write(int b) throws IOException {
+      byte[] buf = new byte[] { (byte) (b & 0xff) };
+      write(buf, 0, buf.length);
+    }
+
+    @Override
+    public void write(byte b[], int off, int len) throws IOException {
+      checkNotFinished();
+      uncompressedBytes += len;
+      crc.update(b, off, len);
+      deflater.setInput(b, off, len);
+      while (!deflater.needsInput()) {
+        deflate();
+      }
+    }
+
+    @Override
+    public void close() throws IOException {
+      super.close();
+      deflater.end();
+    }
+
+    /**
+     * Writes out the remaining buffered data without closing the output
+     * stream.
+     */
+    public void finish() throws IOException {
+      checkNotFinished();
+      deflater.finish();
+      while (!deflater.finished()) {
+        deflate();
+      }
+      if ((compressedBytes >= MAXIMUM_DATA_SIZE) || (uncompressedBytes >= MAXIMUM_DATA_SIZE)) {
+        throw new IOException("Too much data for ZIP entry.");
+      }
+    }
+
+    private void deflate() throws IOException {
+      int length = deflater.deflate(outputBuffer);
+      ZipCombiner.this.write(outputBuffer, 0, length);
+      compressedBytes += length;
+    }
+
+    public int getCRC() {
+      return (int) crc.getValue();
+    }
+
+    public int getCompressedSize() {
+      return (int) compressedBytes;
+    }
+
+    public int getUncompressedSize() {
+      return (int) uncompressedBytes;
+    }
+
+    private void checkNotFinished() {
+      if (deflater.finished()) {
+        throw new IllegalStateException();
+      }
+    }
+  }
+
+  /**
+   * Writes any remaining output data to the output stream and also creates the
+   * merged entries by calling the {@link CustomMergeStrategy} implementations
+   * given back from the ZIP entry filter.
+   *
+   * @throws IOException if the output stream or the filter throws an
+   *                     IOException
    * @throws IllegalStateException if this method was already called earlier
    */
   public void finish() throws IOException {
-    for (Entry<String, EntryAction> entry : actions.entrySet()) {
+    checkNotFinished();
+    finished = true;
+    for (Map.Entry<String, FileEntry> entry : fileNames.entrySet()) {
       String filename = entry.getKey();
-      EntryAction action = entry.getValue();
-      if (action.getType() == ActionType.MERGE) {
-        ByteArrayOutputStream uncompressed = action.getMergeBuffer();
-        action.getStrategy().finish(uncompressed);
-
-        ZipFileEntry e = new ZipFileEntry(filename);
-        e.setTime(action.getDate() != null ? action.getDate().getTime() : new Date().getTime());
-        writeEntryFromBuffer(e, uncompressed.toByteArray());
+      CustomMergeStrategy mergeStrategy = entry.getValue().mergeStrategy;
+      ByteArrayOutputStream outputBuffer = entry.getValue().outputBuffer;
+      int dosTime = entry.getValue().dosTime;
+      if (mergeStrategy == null) {
+        // Do nothing.
+      } else {
+        mergeStrategy.finish(outputBuffer);
+        copyStreamToEntry(filename, new ByteArrayInputStream(outputBuffer.toByteArray()), dosTime,
+            NO_EXTRA_ENTRIES, true, DEFAULT_DIRECTORY_ENTRY_INFO);
       }
     }
-    out.finish();
+
+    // Write central directory.
+    if (out.bytesWritten >= MAXIMUM_DATA_SIZE) {
+      throw new IOException("Unable to handle files bigger than 2^32 bytes.");
+    }
+    int startOfCentralDirectory = (int) out.bytesWritten;
+    int centralDirectorySize = centralDirectory.writeTo(out);
+
+    // end of central directory signature
+    setUnsignedInt(directoryEntryBuffer, 0, END_OF_CENTRAL_DIRECTORY_MARKER);
+    // number of this disk
+    setUnsignedShort(directoryEntryBuffer, 4, (short) 0);
+    // number of the disk with the start of the central directory
+    setUnsignedShort(directoryEntryBuffer, 6, (short) 0);
+    // total number of entries in the central directory on this disk
+    setUnsignedShort(directoryEntryBuffer, 8, (short) fileCount);
+    // total number of entries in the central directory
+    setUnsignedShort(directoryEntryBuffer, 10, (short) fileCount);
+    // size of the central directory
+    setUnsignedInt(directoryEntryBuffer, 12, centralDirectorySize);
+    // offset of start of central directory with respect to the starting disk number
+    setUnsignedInt(directoryEntryBuffer, 16, startOfCentralDirectory);
+    // .ZIP file comment length
+    setUnsignedShort(directoryEntryBuffer, 20, (short) 0);
+    write(directoryEntryBuffer, 0, 22);
+
+    out.flush();
+  }
+
+  private void checkNotFinished() {
+    if (finished) {
+      throw new IllegalStateException();
+    }
   }
 
   /**
    * Writes any remaining output data to the output stream and closes it.
    *
-   * @throws IOException if the output stream or the filter throws an IOException
+   * @throws IOException if the output stream or the filter throws an
+   *                     IOException
    */
-  @Override public void close() throws IOException {
-    finish();
+  @Override
+  public void close() throws IOException {
+    if (!finished) {
+      finish();
+    }
     out.close();
   }
 
-  /** Ensures the truth of an expression involving one or more parameters to the calling method. */
+  /**
+   * Turns this JAR file into an executable JAR by prepending an executable.
+   * JAR files are placed at the end of a file, and executables are placed
+   * at the beginning, so a file can be both, if desired.
+   *
+   * @param launcherIn   The InputStream, from which the launcher is read.
+   * @throws NullPointerException if launcherIn is null
+   * @throws IOException if reading from launcherIn or writing to the output
+   *                     stream throws an IOException.
+   */
+  public void prependExecutable(InputStream launcherIn) throws IOException {
+    if (launcherIn == null) {
+      throw new NullPointerException("No launcher specified");
+    }
+    byte[] buf = new byte[BUFFER_SIZE];
+    int bytesRead;
+    while ((bytesRead = launcherIn.read(buf)) > 0) {
+      out.write(buf, 0, bytesRead);
+    }
+  }
+
+  /**
+   * Ensures the truth of an expression involving one or more parameters to the calling method.
+   */
   private static void checkArgument(boolean expression,
       @Nullable String errorMessageTemplate,
       @Nullable Object... errorMessageArgs) {
@@ -625,18 +1621,18 @@ public class ZipCombiner implements AutoCloseable {
     }
   }
 
-  /** Ensures that an object reference passed as a parameter to the calling method is not null. */
-  public static <T> T checkNotNull(T reference,
-      @Nullable String errorMessageTemplate,
-      @Nullable Object... errorMessageArgs) {
-    if (reference == null) {
-      // If either of these parameters is null, the right thing happens anyway
-      throw new NullPointerException(String.format(errorMessageTemplate, errorMessageArgs));
+  /**
+   * Ensures the truth of an expression involving one or more parameters to the calling method.
+   */
+  private static void checkArgument(boolean expression) {
+    if (!expression) {
+      throw new IllegalArgumentException();
     }
-    return reference;
   }
 
-  /** Ensures the truth of an expression involving state. */
+  /**
+   * Ensures the truth of an expression involving state.
+   */
   private static void checkState(boolean expression,
       @Nullable String errorMessageTemplate,
       @Nullable Object... errorMessageArgs) {
diff --git a/src/java_tools/singlejar/java/com/google/devtools/build/zip/CountingOutputStream.java b/src/java_tools/singlejar/java/com/google/devtools/build/zip/CountingOutputStream.java
deleted file mode 100644
index a08159ff14..0000000000
--- a/src/java_tools/singlejar/java/com/google/devtools/build/zip/CountingOutputStream.java
+++ /dev/null
@@ -1,54 +0,0 @@
-// Copyright 2015 Google Inc. All rights reserved.
-//
-// 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 com.google.devtools.build.zip;
-
-import java.io.FilterOutputStream;
-import java.io.IOException;
-import java.io.OutputStream;
-
-/** An OutputStream that counts the number of bytes written. */
-final class CountingOutputStream extends FilterOutputStream {
-
-  private long count;
-
-  /**
-   * Wraps another output stream, counting the number of bytes written.
-   *
-   * @param out the output stream to be wrapped
-   */
-  public CountingOutputStream(OutputStream out) {
-    super(out);
-  }
-
-  /** Returns the number of bytes written. */
-  public long getCount() {
-    return count;
-  }
-
-  @Override public void write(int b) throws IOException {
-    out.write(b);
-    count++;
-  }
-
-  @Override public void write(byte[] b) throws IOException {
-    out.write(b);
-    count += b.length;
-  }
-
-  @Override public void write(byte[] b, int off, int len) throws IOException {
-    out.write(b, off, len);
-    count += len;
-  }
-}
\ No newline at end of file
diff --git a/src/java_tools/singlejar/java/com/google/devtools/build/zip/README b/src/java_tools/singlejar/java/com/google/devtools/build/zip/README
deleted file mode 100644
index 48d662c547..0000000000
--- a/src/java_tools/singlejar/java/com/google/devtools/build/zip/README
+++ /dev/null
@@ -1,2 +0,0 @@
-Zip is a library for reading and writing zip files, allowing more advanced manipulation than the
-JDK equivalents by providing detailed zip entry data and raw file access.
\ No newline at end of file
diff --git a/src/java_tools/singlejar/java/com/google/devtools/build/zip/ZipFileEntry.java b/src/java_tools/singlejar/java/com/google/devtools/build/zip/ZipFileEntry.java
deleted file mode 100644
index 2b7a410c1f..0000000000
--- a/src/java_tools/singlejar/java/com/google/devtools/build/zip/ZipFileEntry.java
+++ /dev/null
@@ -1,478 +0,0 @@
-// Copyright 2015 Google Inc. All rights reserved.
-//
-// 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 com.google.devtools.build.zip;
-
-import javax.annotation.Nullable;
-
-/**
- * A full representation of a ZIP file entry.
- *
- * <p>See <a href="http://www.pkware.com/documents/casestudies/APPNOTE.TXT">ZIP Format</a> for
- * a description of the entry fields. (Section 4.3.7 and 4.4)
- */
-public final class ZipFileEntry {
-
-  /** Compression method for ZIP entries. */
-  public enum Compression {
-    STORED((short) 0, (short) 0x0a),
-    DEFLATED((short) 8, (short) 0x14);
-
-    public static Compression fromValue(int value) {
-      for (Compression c : Compression.values()) {
-        if (c.getValue() == value) {
-          return c;
-        }
-      }
-      return null;
-    }
-
-    private short value;
-    private short minVersion;
-
-    private Compression(short value, short minVersion) {
-      this.value = value;
-      this.minVersion = minVersion;
-    }
-
-    public short getValue() {
-      return value;
-    }
-
-    public short getMinVersion() {
-      return minVersion;
-    }
-  }
-
-  /** General purpose bit flag for ZIP entries. */
-  public enum Flag {
-    DATA_DESCRIPTOR(3);
-
-    private int bit;
-
-    private Flag(int bit) {
-      this.bit = bit;
-    }
-
-    public int getBit() {
-      return bit;
-    }
-  }
-
-  private String name;
-  private long time = -1;
-  private long crc = -1;
-  private long size = -1;
-  private long csize = -1;
-  private Compression method;
-  private short version = -1;
-  private short versionNeeded = -1;
-  private short flags;
-  private short internalAttributes;
-  private int externalAttributes;
-  private long localHeaderOffset = -1;
-  @Nullable private byte[] extra;
-  @Nullable private String comment;
-
-  /**
-   * Creates a new zip entry with the specified name.
-   *
-   * @param name the entry name
-   * @throws NullPointerException if the entry name is null
-   */
-  public ZipFileEntry(String name) {
-    setName(name);
-  }
-
-  /**
-   * Creates a new zip entry with fields taken from the specified zip entry.
-   *
-   * @param e a zip entry object
-   */
-  public ZipFileEntry(ZipFileEntry e) {
-    if (e == null) {
-      throw new NullPointerException();
-    }
-    this.name = e.getName();
-    this.time = e.getTime();
-    this.crc = e.getCrc();
-    this.size = e.getSize();
-    this.csize = e.getCompressedSize();
-    this.method = e.getMethod();
-    this.version = e.getVersion();
-    this.versionNeeded = e.getVersionNeeded();
-    this.flags = e.getFlags();
-    this.internalAttributes = e.getInternalAttributes();
-    this.externalAttributes = e.getExternalAttributes();
-    this.localHeaderOffset = e.getLocalHeaderOffset();
-    this.extra = e.getExtra();
-    this.comment = e.getComment();
-  }
-
-  /**
-   * Sets the name of the entry.
-   *
-   * @param name the name
-   */
-  public void setName(String name) {
-    if (name == null) {
-      throw new NullPointerException();
-    }
-    this.name = name;
-  }
-
-  /**
-   * Returns the name of the entry.
-   *
-   * @return the name of the entry
-   */
-  public String getName() {
-    return name;
-  }
-
-  /**
-   * Sets the modification time of the entry.
-   *
-   * @param time the entry modification time in number of milliseconds since the epoch
-   */
-  public void setTime(long time) {
-    this.time = time;
-  }
-
-  /**
-   * Returns the modification time of the entry, or -1 if not specified.
-   *
-   * @return the modification time of the entry, or -1 if not specified
-   */
-  public long getTime() {
-    return time;
-  }
-
-  /**
-   * Sets the CRC-32 checksum of the uncompressed entry data.
-   *
-   * @param crc the CRC-32 value
-   * @throws IllegalArgumentException if the specified CRC-32 value is less than 0 or greater than
-   *     0xFFFFFFFF
-   */
-  public void setCrc(long crc) {
-    if (crc < 0 || crc > 0xffffffffL) {
-      throw new IllegalArgumentException("invalid entry crc-32");
-    }
-    this.crc = crc;
-  }
-
-  /**
-   * Returns the CRC-32 checksum of the uncompressed entry data, or -1 if not known.
-   *
-   * @return the CRC-32 checksum of the uncompressed entry data, or -1 if not known
-   */
-  public long getCrc() {
-    return crc;
-  }
-
-  /**
-   * Sets the uncompressed size of the entry data.
-   *
-   * @param size the uncompressed size in bytes
-   * @throws IllegalArgumentException if the specified size is less than 0, is greater than
-   *     0xFFFFFFFF
-   */
-  public void setSize(long size) {
-    if (size < 0 || size > 0xffffffffL) {
-      throw new IllegalArgumentException("invalid entry size");
-    }
-    this.size = size;
-  }
-
-  /**
-   * Returns the uncompressed size of the entry data, or -1 if not known.
-   *
-   * @return the uncompressed size of the entry data, or -1 if not known
-   */
-  public long getSize() {
-    return size;
-  }
-
-  /**
-   * Sets the size of the compressed entry data.
-   *
-   * @param csize the compressed size in bytes
-   * @throws IllegalArgumentException if the specified size is less than 0, is greater than
-   *     0xFFFFFFFF
-   */
-  public void setCompressedSize(long csize) {
-    if (csize < 0 || csize > 0xffffffffL) {
-      throw new IllegalArgumentException("invalid entry size");
-    }
-    this.csize = csize;
-  }
-
-  /**
-   * Returns the size of the compressed entry data, or -1 if not known. In the case of a stored
-   * entry, the compressed size will be the same as the uncompressed size of the entry.
-   *
-   * @return the size of the compressed entry data, or -1 if not known
-   */
-  public long getCompressedSize() {
-    return csize;
-  }
-
-  /**
-   * Sets the compression method for the entry. Increases the version and version needed if the new
-   * compression method requires a higher version.
-   *
-   * @param method the compression method, either STORED or DEFLATED
-   */
-  public void setMethod(Compression method) {
-    if (method == null) {
-      throw new NullPointerException();
-    }
-    this.method = method;
-    short minVersion = method.getMinVersion();
-    version = (short) Math.max(version, minVersion);
-    versionNeeded = (short) Math.max(versionNeeded, minVersion);
-  }
-
-  /**
-   * Returns the compression method of the entry.
-   *
-   * @return the compression method of the entry
-   */
-  public Compression getMethod() {
-    return method;
-  }
-
-  /**
-   * Sets the made by version for the entry.
-   *
-   * @param version the made by version to set
-   * @throws IllegalArgumentException if the specified version is less than the required version for
-   *     the specified compression method
-   */
-  public void setVersion(short version) {
-    if (method != null && version < method.getMinVersion()) {
-      throw new IllegalArgumentException(String.format(
-          "The minimum allowable version for method %s is 0x%02x.",
-          method.name(), method.getMinVersion()));
-    }
-    this.version = version;
-  }
-
-  /**
-   * Returns the made by version of the entry.
-   *
-   * @return the made by version of the entry
-   */
-  public short getVersion() {
-    return version;
-  }
-
-  /**
-   * Sets the version needed to extract the entry.
-   *
-   * @param versionNeeded the version needed to extract to set
-   * @throws IllegalArgumentException if the specified version is less than the required version for
-   *     the specified compression method
-   */
-  public void setVersionNeeded(short versionNeeded) {
-    if (method != null && versionNeeded < method.getMinVersion()) {
-      throw new IllegalArgumentException(String.format(
-          "The minimum allowable version for method %s is 0x%02x.",
-          method.name(), method.getMinVersion()));
-    }
-    this.versionNeeded = versionNeeded;
-  }
-
-  /**
-   * Returns the version needed to extract the entry.
-   *
-   * @return the version needed to extract the entry
-   */
-  public short getVersionNeeded() {
-    return versionNeeded;
-  }
-
-  /**
-   * Sets the general purpose bit flags for the entry.
-   *
-   * @param flags the general purpose bit flags to set
-   */
-  public void setFlags(short flags) {
-    this.flags = flags;
-  }
-
-  /**
-   * Sets or clears the specified bit of the general purpose bit flags.
-   *
-   * @param flag the flag to set or clear
-   * @param set whether the flag is to be set or cleared
-   */
-  public void setFlag(Flag flag, boolean set) {
-    short mask = 0x0000;
-    mask |= 1 << flag.getBit();
-    if (set) {
-      flags |= mask;
-    } else {
-      flags &= ~mask;
-    }
-  }
-
-  /**
-   * Returns the general purpose bit flags of the entry.
-   *
-   * <p>See <a href="http://www.pkware.com/documents/casestudies/APPNOTE.TXT">ZIP Format</a>
-   * section 4.4.4.
-   *
-   * @return the general purpose bit flags of the entry
-   */
-  public short getFlags() {
-    return flags;
-  }
-
-  /**
-   * Sets the internal file attributes of the entry.
-   *
-   * @param internalAttributes the internal file attributes to set
-   */
-  public void setInternalAttributes(short internalAttributes) {
-    this.internalAttributes = internalAttributes;
-  }
-
-  /**
-   * Returns the internal file attributes of the entry.
-   *
-   * @return the internal file attributes of the entry
-   */
-  public short getInternalAttributes() {
-    return internalAttributes;
-  }
-
-  /**
-   * Sets the external file attributes of the entry.
-   *
-   * @param externalAttributes the external file attributes to set
-   */
-  public void setExternalAttributes(int externalAttributes) {
-    this.externalAttributes = externalAttributes;
-  }
-
-  /**
-   * Returns the external file attributes of the entry.
-   *
-   * @return the external file attributes of the entry
-   */
-  public int getExternalAttributes() {
-    return externalAttributes;
-  }
-
-  /**
-   * Sets the file offset, in bytes, of the location of the local file header for the entry.
-   *
-   * <p>See <a href="http://www.pkware.com/documents/casestudies/APPNOTE.TXT">ZIP Format</a>
-   * section 4.4.16
-   *
-   * @param localHeaderOffset the file offset of the local header to set
-   * @throws IllegalArgumentException if the specified local header offset is less than 0 or greater
-   *     than 0xFFFFFFFF
-   */
-  void setLocalHeaderOffset(long localHeaderOffset) {
-    if (localHeaderOffset < 0 || localHeaderOffset > 0xffffffffL) {
-      throw new IllegalArgumentException("invalid local header offset");
-    }
-    this.localHeaderOffset = localHeaderOffset;
-  }
-
-  /**
-   * Returns the file offset of the local header of the entry.
-   *
-   * @return the file offset of the local header of the entry
-   */
-  public long getLocalHeaderOffset() {
-    return localHeaderOffset;
-  }
-
-  /**
-   * Sets the optional extra field data for the entry.
-   *
-   * <p><em>NOTE:</em> This sets the extra field exactly as specified. Use
-   * {@link #setExtra(ExtraData[])} to guarantee well formed extra field entries.
-   *
-   * @param extra the extra field data bytes
-   * @throws IllegalArgumentException if the length of the specified extra field data is greater
-   *    than 0xFFFF bytes
-   */
-  public void setExtra(@Nullable byte[] extra) {
-    if (extra != null && extra.length > 0xffff) {
-      throw new IllegalArgumentException("invalid extra field length");
-    }
-    this.extra = extra;
-  }
-
-  /**
-   * Sets the optional extra field data from the provided {@link ExtraData} array. Performs the
-   * necessary conversion to the raw byte array.
-   *
-   * <p><em>NOTE:</em> This will guarantee well formed extra field entries, but cannot guarantee
-   * usable data if Id or Data is specified incorrectly in {@link ExtraData}.
-   *
-   * @param extra the extra field data
-   * @throws IllegalArgumentException if the length of the specified extra field data is greater
-   *    than 0xFFFF bytes
-   */
-  public void setExtra(ExtraData[] extra) {
-    int extraDataLength = 0;
-    for (ExtraData e : extra) {
-      extraDataLength += 4 + e.getData().length;
-    }
-
-    byte[] rawExtra = new byte[extraDataLength];
-
-    int index = 0;
-    for (ExtraData e : extra) {
-      ZipUtil.shortToLittleEndian(rawExtra, index, e.getId());
-      ZipUtil.shortToLittleEndian(rawExtra, index + 2, (short) (e.getData().length & 0xffff));
-      System.arraycopy(e.getData(), 0, rawExtra, index + 4, e.getData().length);
-      index += 4 + e.getData().length;
-    }
-    setExtra(rawExtra);
-  }
-
-  /**
-   * Returns the extra field data for the entry, or null if none.
-   *
-   * @return the extra field data for the entry, or null if none
-   */
-  public byte[] getExtra() {
-    return extra;
-  }
-
-  /**
-   * Sets the optional comment string for the entry.
-   *
-   * @param comment the comment string
-   */
-  public void setComment(@Nullable String comment) {
-    this.comment = comment;
-  }
-
-  /**
-   * Returns the comment string for the entry, or null if none.
-   *
-   * @return the comment string for the entry, or null if none
-   */
-  public String getComment() {
-    return comment;
-  }
-}
diff --git a/src/java_tools/singlejar/java/com/google/devtools/build/zip/ZipReader.java b/src/java_tools/singlejar/java/com/google/devtools/build/zip/ZipReader.java
deleted file mode 100644
index 66f948e05d..0000000000
--- a/src/java_tools/singlejar/java/com/google/devtools/build/zip/ZipReader.java
+++ /dev/null
@@ -1,472 +0,0 @@
-// Copyright 2015 Google Inc. All rights reserved.
-//
-// 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 com.google.devtools.build.zip;
-
-import static java.nio.charset.StandardCharsets.UTF_8;
-
-import com.google.devtools.build.zip.ZipFileEntry.Compression;
-import com.google.devtools.build.zip.ZipUtil.CentralDirectoryFileHeader;
-import com.google.devtools.build.zip.ZipUtil.EndOfCentralDirectoryRecord;
-import com.google.devtools.build.zip.ZipUtil.LocalFileHeader;
-
-import java.io.BufferedInputStream;
-import java.io.Closeable;
-import java.io.File;
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.RandomAccessFile;
-import java.nio.channels.Channels;
-import java.nio.charset.Charset;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.LinkedHashMap;
-import java.util.Map;
-import java.util.zip.Inflater;
-import java.util.zip.InflaterInputStream;
-import java.util.zip.ZipEntry;
-import java.util.zip.ZipException;
-import java.util.zip.ZipFile;
-
-/**
- * A ZIP file reader.
- *
- * <p>This class provides entry data in the form of {@link ZipFileEntry}, which provides more detail
- * about the entry than the JDK equivalent {@link ZipEntry}. In addition to providing
- * {@link InputStream}s for entries, similar to JDK {@link ZipFile#getInputStream(ZipEntry)}, it
- * also provides access to the raw byte entry data via {@link #getRawInputStream(ZipFileEntry)}.
- *
- * <p>Using the raw access capabilities allows for more efficient ZIP file processing, such as
- * merging, by not requiring each entry's data to be decompressed when read.
- *
- * <p><em>NOTE:</em> The entries are read from the central directory. If the entry is not listed
- * there, it will not be returned from {@link #entries()} or {@link #getEntry(String)}.
- */
-public class ZipReader implements Closeable, AutoCloseable {
-
-  /** An input stream for reading the file data of a ZIP file entry. */
-  private class ZipEntryInputStream extends InputStream {
-    private InputStream stream;
-    private long rem;
-
-    /**
-     * Opens an input stream for reading at the beginning of the ZIP file entry's content.
-     *
-     * @param zipEntry the ZIP file entry to open the input stream for
-     * @throws ZipException if a ZIP format error has occurred
-     * @throws IOException if an I/O error has occurred
-     */
-    private ZipEntryInputStream(ZipFileEntry zipEntry) throws IOException {
-      stream = new BufferedInputStream(Channels.newInputStream(
-          in.getChannel().position(zipEntry.getLocalHeaderOffset())));
-
-      byte[] fileHeader = new byte[LocalFileHeader.FIXED_DATA_SIZE];
-      stream.read(fileHeader);
-
-      if (!ZipUtil.arrayStartsWith(fileHeader,
-          ZipUtil.intToLittleEndian(LocalFileHeader.SIGNATURE))) {
-        throw new ZipException(String.format("The file '%s' is not a correctly formatted zip file: "
-            + "Expected a File Header at file offset %d, but was not present.",
-            file.getName(), zipEntry.getLocalHeaderOffset()));
-      }
-
-      int nameLength = ZipUtil.getUnsignedShort(fileHeader,
-          LocalFileHeader.FILENAME_LENGTH_OFFSET);
-      int extraFieldLength = ZipUtil.getUnsignedShort(fileHeader,
-          LocalFileHeader.EXTRA_FIELD_LENGTH_OFFSET);
-      stream.skip(nameLength + extraFieldLength);
-      rem = zipEntry.getSize();
-      if (zipEntry.getMethod() == Compression.DEFLATED) {
-        stream = new InflaterInputStream(stream, new Inflater(true));
-      }
-    }
-
-    @Override public int available() throws IOException {
-      return rem > Integer.MAX_VALUE ? Integer.MAX_VALUE : (int) rem;
-    }
-
-    @Override public void close() throws IOException {
-    }
-
-    @Override public void mark(int readlimit) {
-    }
-
-    @Override public boolean markSupported() {
-      return false;
-    }
-
-    @Override public int read() throws IOException {
-      byte[] b = new byte[1];
-      if (read(b, 0, 1) == 1) {
-        return b[0] & 0xff;
-      } else {
-        return -1;
-      }
-    }
-
-    @Override public int read(byte[] b) throws IOException {
-      return read(b, 0, b.length);
-    }
-
-    @Override public int read(byte[] b, int off, int len) throws IOException {
-      if (rem == 0) {
-        return -1;
-      }
-      if (len > rem) {
-        len = available();
-      }
-      len = stream.read(b, off, len);
-      rem -= len;
-      return len;
-    }
-
-    @Override public long skip(long n) throws IOException {
-      if (n > rem) {
-        n = rem;
-      }
-      n = stream.skip(n);
-      rem -= n;
-      return n;
-    }
-
-    @Override public void reset() throws IOException {
-      throw new IOException("Reset is not supported on this type of stream.");
-    }
-  }
-
-  /** An input stream for reading the raw file data of a ZIP file entry. */
-  private class RawZipEntryInputStream extends InputStream {
-    private InputStream stream;
-    private long rem;
-
-    /**
-     * Opens an input stream for reading at the beginning of the ZIP file entry's content.
-     *
-     * @param zipEntry the ZIP file entry to open the input stream for
-     * @throws ZipException if a ZIP format error has occurred
-     * @throws IOException if an I/O error has occurred
-     */
-    private RawZipEntryInputStream(ZipFileEntry zipEntry) throws IOException {
-      stream = new BufferedInputStream(Channels.newInputStream(
-          in.getChannel().position(zipEntry.getLocalHeaderOffset())));
-
-      byte[] fileHeader = new byte[LocalFileHeader.FIXED_DATA_SIZE];
-      stream.read(fileHeader);
-
-      if (!ZipUtil.arrayStartsWith(fileHeader,
-          ZipUtil.intToLittleEndian(LocalFileHeader.SIGNATURE))) {
-        throw new ZipException(String.format("The file '%s' is not a correctly formatted zip file: "
-            + "Expected a File Header at file offset %d, but was not present.",
-            file.getName(), zipEntry.getLocalHeaderOffset()));
-      }
-
-      int nameLength = ZipUtil.getUnsignedShort(fileHeader,
-          LocalFileHeader.FILENAME_LENGTH_OFFSET);
-      int extraFieldLength = ZipUtil.getUnsignedShort(fileHeader,
-          LocalFileHeader.EXTRA_FIELD_LENGTH_OFFSET);
-      stream.skip(nameLength + extraFieldLength);
-      rem = zipEntry.getCompressedSize();
-    }
-
-    @Override public int available() throws IOException {
-      return rem > Integer.MAX_VALUE ? Integer.MAX_VALUE : (int) rem;
-    }
-
-    @Override public void close() throws IOException {
-    }
-
-    @Override public void mark(int readlimit) {
-    }
-
-    @Override public boolean markSupported() {
-      return false;
-    }
-
-    @Override public int read() throws IOException {
-      byte[] b = new byte[1];
-      if (read(b, 0, 1) == 1) {
-        return b[0] & 0xff;
-      } else {
-        return -1;
-      }
-    }
-
-    @Override public int read(byte[] b) throws IOException {
-      return read(b, 0, b.length);
-    }
-
-    @Override public int read(byte[] b, int off, int len) throws IOException {
-      if (rem == 0) {
-        return -1;
-      }
-      if (len > rem) {
-        len = available();
-      }
-      len = stream.read(b, off, len);
-      rem -= len;
-      return len;
-    }
-
-    @Override public long skip(long n) throws IOException {
-      if (n > rem) {
-        n = rem;
-      }
-      n = stream.skip(n);
-      rem -= n;
-      return n;
-    }
-
-    @Override public void reset() throws IOException {
-      throw new IOException("Reset is not supported on this type of stream.");
-    }
-  }
-
-  private File file;
-  private Charset charset;
-  private RandomAccessFile in;
-  private Map<String, ZipFileEntry> zipEntries;
-  private String comment;
-
-  /**
-   * Opens a zip file for raw acceess.
-   *
-   * <p>The UTF-8 charset is used to decode the entry names and comments.
-   *
-   * @param file the zip file
-   * @throws ZipException if a ZIP format error has occurred
-   * @throws IOException if an I/O error has occurred
-   */
-  public ZipReader(File file) throws IOException {
-    this(file, UTF_8);
-  }
-
-  /**
-   * Opens a zip file for raw acceess.
-   *
-   * @param file the zip file
-   * @param charset the charset to use to decode the entry names and comments.
-   * @throws ZipException if a ZIP format error has occurred
-   * @throws IOException if an I/O error has occurred
-   */
-  public ZipReader(File file, Charset charset) throws IOException {
-    if (file == null || charset == null) {
-      throw new NullPointerException();
-    }
-    this.file = file;
-    this.charset = charset;
-    this.in = new RandomAccessFile(file, "r");
-    this.zipEntries = readCentralDirectory();
-  }
-
-  /**
-   * Returns the ZIP file comment.
-   *
-   * @return the ZIP file comment
-   */
-  public String getComment() {
-    return comment;
-  }
-
-  /**
-   * Returns a collection of the ZIP file entries.
-   *
-   * @return a collection of the ZIP file entries
-   */
-  public Collection<ZipFileEntry> entries() {
-    return zipEntries.values();
-  }
-
-  /**
-   * Returns the ZIP file entry for the specified name, or null if not found.
-   *
-   * @param name the name of the entry
-   * @return the ZIP file entry, or null if not found
-   */
-  public ZipFileEntry getEntry(String name) {
-    if (zipEntries.containsKey(name)) {
-      return zipEntries.get(name);
-    } else {
-      return null;
-    }
-  }
-
-  /**
-   * Returns an input stream for reading the contents of the specified ZIP file entry.
-   *
-   * <p>Closing this ZIP file will, in turn, close all input streams that have been returned by
-   * invocations of this method.
-   *
-   * @param entry the ZIP file entry
-   * @return the input stream for reading the contents of the specified zip file entry
-   * @throws ZipException if a ZIP format error has occurred
-   * @throws IOException if an I/O error has occurred
-   */
-  public InputStream getInputStream(ZipFileEntry entry) throws IOException {
-    if (!zipEntries.get(entry.getName()).equals(entry)) {
-      throw new ZipException(String.format(
-          "Zip file '%s' does not contain the requested entry '%s'.", file.getName(),
-          entry.getName()));
-    }
-    return new ZipEntryInputStream(entry);
-  }
-
-  /**
-   * Returns an input stream for reading the raw contents of the specified ZIP file entry.
-   *
-   * <p><em>NOTE:</em> No inflating will take place; The data read from the input stream will be
-   * the exact byte content of the ZIP file entry on disk.
-   *
-   * <p>Closing this ZIP file will, in turn, close all input streams that have been returned by
-   * invocations of this method.
-   *
-   * @param entry the ZIP file entry
-   * @return the input stream for reading the contents of the specified zip file entry
-   * @throws ZipException if a ZIP format error has occurred
-   * @throws IOException if an I/O error has occurred
-   */
-  public InputStream getRawInputStream(ZipFileEntry entry) throws IOException {
-    if (!zipEntries.get(entry.getName()).equals(entry)) {
-      throw new ZipException(String.format(
-          "Zip file '%s' does not contain the requested entry '%s'.", file.getName(),
-          entry.getName()));
-    }
-    return new RawZipEntryInputStream(entry);
-  }
-
-  /**
-   * Closes the ZIP file.
-   *
-   * <p>Closing this ZIP file will close all of the input streams previously returned by invocations
-   * of the {@link #getRawInputStream(ZipFileEntry)} method.
-   */
-  @Override public void close() throws IOException {
-    in.close();
-  }
-
-  /**
-   * Finds, reads and parses ZIP file entries from the central directory.
-   *
-   * @return a map of all ZIP file entries read from the central directory and their names
-   * @throws ZipException if a ZIP format error has occurred
-   * @throws IOException if an I/O error has occurred
-   */
-  private Map<String, ZipFileEntry> readCentralDirectory() throws IOException {
-    byte[] eocdRecord = readEndOfCentralDirectoryRecord();
-
-    int commentLength = ZipUtil.getUnsignedShort(eocdRecord,
-        EndOfCentralDirectoryRecord.COMMENT_LENGTH_OFFSET);
-    this.comment = new String(Arrays.copyOfRange(eocdRecord,
-        EndOfCentralDirectoryRecord.FIXED_DATA_SIZE,
-        EndOfCentralDirectoryRecord.FIXED_DATA_SIZE + commentLength), charset);
-
-    int totalEntries = ZipUtil.getUnsignedShort(eocdRecord,
-        EndOfCentralDirectoryRecord.TOTAL_ENTRIES_OFFSET);
-    long cdOffset = ZipUtil.getUnsignedInt(eocdRecord,
-        EndOfCentralDirectoryRecord.CD_OFFSET_OFFSET);
-
-    return readCentralDirectoryFileHeaders(totalEntries, cdOffset);
-  }
-
-  /**
-   * Looks for the target sub array in the buffer scanning backwards starting at offset. Returns the
-   * index where the target is found or -1 if not found.
-   *
-   * @param target the sub array to find
-   * @param buffer the array to scan
-   * @param offset the index of where to begin scanning
-   * @return the index of target within buffer or -1 if not found
-   */
-  private int scanBackwards(byte[] target, byte[] buffer, int offset) {
-    int start = Math.min(offset, buffer.length - target.length);
-    for (int i = start; i >= 0; i--) {
-      for (int j = 0; j < target.length; j++) {
-        if (buffer[i + j] != target[j]) {
-          break;
-        } else if (j == target.length - 1) {
-          return i;
-        }
-      }
-    }
-    return -1;
-  }
-
-  /**
-   * Finds and returns the byte array of the end of central directory record.
-   *
-   * @return the byte array of the end of central directory record
-   * @throws ZipException if a ZIP format error has occurred
-   * @throws IOException if an I/O error has occurred
-   */
-  private byte[] readEndOfCentralDirectoryRecord() throws IOException {
-    byte[] signature = ZipUtil.intToLittleEndian(EndOfCentralDirectoryRecord.SIGNATURE);
-    byte[] buffer = new byte[(int) Math.min(64, in.length())];
-
-    int bytesRead = 0;
-    while (true) {
-      in.seek(in.length() - buffer.length);
-      in.readFully(buffer, 0, buffer.length - bytesRead);
-
-      int signatureLocation = scanBackwards(signature, buffer, buffer.length - bytesRead - 1);
-      while (signatureLocation != -1) {
-        int eocdSize = buffer.length - signatureLocation;
-        if (eocdSize >= EndOfCentralDirectoryRecord.FIXED_DATA_SIZE) {
-          int commentLength = ZipUtil.getUnsignedShort(buffer, signatureLocation
-              + EndOfCentralDirectoryRecord.COMMENT_LENGTH_OFFSET);
-          int readCommentLength = buffer.length - signatureLocation
-              - EndOfCentralDirectoryRecord.FIXED_DATA_SIZE;
-          if (commentLength == readCommentLength) {
-            byte[] eocdRecord = new byte[eocdSize];
-            System.arraycopy(buffer, signatureLocation, eocdRecord, 0, eocdSize);
-            return eocdRecord;
-          }
-        }
-        signatureLocation = scanBackwards(signature, buffer, signatureLocation - 1);
-      }
-      // expand buffer
-      bytesRead = buffer.length;
-      int newLength = (int) Math.min(buffer.length * 2, in.length());
-      if (newLength == buffer.length) {
-        break;
-      }
-      byte[] newBuf = new byte[newLength];
-      System.arraycopy(buffer, 0, newBuf, newBuf.length - buffer.length, buffer.length);
-      buffer = newBuf;
-    }
-    throw new ZipException(String.format("Zip file '%s' is malformed. It does not contain an end"
-        + " of central directory record.", file.getName()));
-  }
-
-  /**
-   * Reads and parses ZIP file entries from the central directory.
-   *
-   * @param count the number of entries in the central directory
-   * @param fileOffset the file offset of the start of the central directory
-   * @return a map of all ZIP file entries read from the central directory and their names
-   * @throws ZipException if a ZIP format error has occurred
-   * @throws IOException if an I/O error has occurred
-   */
-  private Map<String, ZipFileEntry> readCentralDirectoryFileHeaders(int count, long fileOffset)
-      throws IOException {
-
-    InputStream centralDirectory = new BufferedInputStream(
-        Channels.newInputStream(in.getChannel().position(fileOffset)));
-
-    Map<String, ZipFileEntry> entries = new LinkedHashMap<>(count);
-    for (int i = 0; i < count; i++) {
-      ZipFileEntry entry = CentralDirectoryFileHeader.read(centralDirectory, charset);
-      entries.put(entry.getName(), entry);
-    }
-    return entries;
-  }
-}
diff --git a/src/java_tools/singlejar/java/com/google/devtools/build/zip/ZipUtil.java b/src/java_tools/singlejar/java/com/google/devtools/build/zip/ZipUtil.java
deleted file mode 100644
index 740f425ff4..0000000000
--- a/src/java_tools/singlejar/java/com/google/devtools/build/zip/ZipUtil.java
+++ /dev/null
@@ -1,418 +0,0 @@
-// Copyright 2015 Google Inc. All rights reserved.
-//
-// 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 com.google.devtools.build.zip;
-
-import com.google.devtools.build.zip.ZipFileEntry.Compression;
-
-import java.io.IOException;
-import java.io.InputStream;
-import java.io.OutputStream;
-import java.nio.charset.Charset;
-import java.text.DateFormat;
-import java.text.SimpleDateFormat;
-import java.util.Calendar;
-import java.util.Collection;
-import java.util.Date;
-import java.util.GregorianCalendar;
-import java.util.zip.ZipException;
-
-/** A utility class for reading and writing {@link ZipFileEntry}s from byte arrays. */
-public class ZipUtil {
-
-  /**
-   * Midnight Jan 1st 1980. Uses the current time zone as the DOS format does not support time zones
-   * and will always assume the current zone.
-   */
-  public static final long DOS_EPOCH =
-      new GregorianCalendar(1980, Calendar.JANUARY, 1, 0, 0, 0).getTimeInMillis();
-
-  /** 23:59:59 Dec 31st 2107. The maximum date representable in DOS format. */
-  public static final long MAX_DOS_DATE =
-      new GregorianCalendar(2107, Calendar.DECEMBER, 31, 23, 59, 59).getTimeInMillis();
-
-  /** Converts a integral value to the corresponding little endian array. */
-  private static byte[] integerToLittleEndian(byte[] buf, int offset, long value, int numBytes) {
-    for (int i = 0; i < numBytes; i++) {
-      buf[i + offset] = (byte) ((value & (0xffL << (i * 8))) >> (i * 8));
-    }
-    return buf;
-  }
-
-  /** Converts a short to the corresponding 2-byte little endian array. */
-  static byte[] shortToLittleEndian(short value) {
-    return integerToLittleEndian(new byte[2], 0, value, 2);
-  }
-
-  /** Writes a short to the buffer as a 2-byte little endian array starting at offset. */
-  static byte[] shortToLittleEndian(byte[] buf, int offset, short value) {
-    return integerToLittleEndian(buf, offset, value, 2);
-  }
-
-  /** Converts an int to the corresponding 4-byte little endian array. */
-  static byte[] intToLittleEndian(int value) {
-    return integerToLittleEndian(new byte[4], 0, value, 4);
-  }
-
-  /** Writes an int to the buffer as a 4-byte little endian array starting at offset. */
-  static byte[] intToLittleEndian(byte[] buf, int offset, int value) {
-    return integerToLittleEndian(buf, offset, value, 4);
-  }
-
-  /** Converts a long to the corresponding 8-byte little endian array. */
-  static byte[] longToLittleEndian(long value) {
-    return integerToLittleEndian(new byte[8], 0, value, 8);
-  }
-
-  /** Writes a long to the buffer as a 8-byte little endian array starting at offset. */
-  static byte[] longToLittleEndian(byte[] buf, int offset, long value) {
-    return integerToLittleEndian(buf, offset, value, 8);
-  }
-
-  /** Reads 16 bits in little-endian byte order from the buffer at the given offset. */
-  static short get16(byte[] source, int offset) {
-    int a = source[offset + 0] & 0xff;
-    int b = source[offset + 1] & 0xff;
-    return (short) ((b << 8) | a);
-  }
-
-  /** Reads 32 bits in little-endian byte order from the buffer at the given offset. */
-  static int get32(byte[] source, int offset) {
-    int a = source[offset + 0] & 0xff;
-    int b = source[offset + 1] & 0xff;
-    int c = source[offset + 2] & 0xff;
-    int d = source[offset + 3] & 0xff;
-    return (d << 24) | (c << 16) | (b << 8) | a;
-  }
-
-  /**
-   * Reads an unsigned short in little-endian byte order from the buffer at the given offset.
-   * Casts to an int to allow proper numerical comparison.
-   */
-  static int getUnsignedShort(byte[] source, int offset) {
-    return get16(source, offset) & 0xffff;
-  }
-
-  /**
-   * Reads an unsigned int in little-endian byte order from the buffer at the given offset.
-   * Casts to a long to allow proper numerical comparison.
-   */
-  static long getUnsignedInt(byte[] source, int offset) {
-    return get32(source, offset) & 0xffffffffL;
-  }
-
-  /** Checks if the timestamp is representable as a valid DOS timestamp. */
-  private static boolean isValidInDos(long timestamp) {
-    Calendar time = Calendar.getInstance();
-    time.setTimeInMillis(timestamp);
-    Calendar minTime = Calendar.getInstance();
-    minTime.setTimeInMillis(DOS_EPOCH);
-    Calendar maxTime = Calendar.getInstance();
-    maxTime.setTimeInMillis(MAX_DOS_DATE);
-    return (!time.before(minTime) && !time.after(maxTime));
-  }
-
-  /** Converts a unix timestamp into a 32-bit DOS timestamp. */
-  static int unixToDosTime(long timestamp) {
-    Calendar time = Calendar.getInstance();
-    time.setTimeInMillis(timestamp);
-
-    if (!isValidInDos(timestamp)) {
-      DateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
-      throw new IllegalArgumentException(String.format("%s is not representable in the DOS time"
-          + " format. It must be in the range %s to %s", df.format(time.getTime()),
-          df.format(new Date(DOS_EPOCH)), df.format(new Date(MAX_DOS_DATE))));
-    }
-
-    int dos = time.get(Calendar.SECOND) >> 1;
-    dos |= time.get(Calendar.MINUTE) << 5;
-    dos |= time.get(Calendar.HOUR_OF_DAY) << 11;
-    dos |= time.get(Calendar.DAY_OF_MONTH) << 16;
-    dos |= (time.get(Calendar.MONTH) + 1) << 21;
-    dos |= (time.get(Calendar.YEAR) - 1980) << 25;
-    return dos;
-  }
-
-  /** Converts a 32-bit DOS timestamp into a unix timestamp. */
-  static long dosToUnixTime(int timestamp) {
-    Calendar time = Calendar.getInstance();
-    time.clear();
-    time.set(Calendar.SECOND, (timestamp << 1) & 0x3e);
-    time.set(Calendar.MINUTE, (timestamp >> 5) & 0x3f);
-    time.set(Calendar.HOUR_OF_DAY, (timestamp >> 11) & 0x1f);
-    time.set(Calendar.DAY_OF_MONTH, (timestamp >> 16) & 0x1f);
-    time.set(Calendar.MONTH, ((timestamp >> 21) & 0x0f) - 1);
-    time.set(Calendar.YEAR, ((timestamp >> 25) & 0x7f) + 1980);
-    return time.getTimeInMillis();
-  }
-
-  /** Checks if array starts with target. */
-  static boolean arrayStartsWith(byte[] array, byte[] target) {
-    if (array == null) {
-      return false;
-    }
-    if (target == null) {
-      return true;
-    }
-    if (target.length > array.length) {
-      return false;
-    }
-    for (int i = 0; i < target.length; i++) {
-      if (array[i] != target[i]) {
-        return false;
-      }
-    }
-    return true;
-  }
-
-  static class LocalFileHeader {
-    static final int SIGNATURE = 0x04034b50;
-    static final int FIXED_DATA_SIZE = 30;
-    static final int SIGNATURE_OFFSET = 0;
-    static final int VERSION_OFFSET = 4;
-    static final int FLAGS_OFFSET = 6;
-    static final int METHOD_OFFSET = 8;
-    static final int MOD_TIME_OFFSET = 10;
-    static final int CRC_OFFSET = 14;
-    static final int COMPRESSED_SIZE_OFFSET = 18;
-    static final int UNCOMPRESSED_SIZE_OFFSET = 22;
-    static final int FILENAME_LENGTH_OFFSET = 26;
-    static final int EXTRA_FIELD_LENGTH_OFFSET = 28;
-    static final int VARIABLE_DATA_OFFSET = 30;
-
-    /**
-     * Generates the raw byte data of the local file header for the ZipEntry. Uses the specified
-     * charset to encode the file name and comment.
-     */
-    static byte[] create(ZipFileEntry entry, Charset charset) {
-      byte[] name = entry.getName().getBytes(charset);
-      byte[] extra = entry.getExtra() != null ? entry.getExtra() : new byte[]{};
-
-      byte[] buf = new byte[FIXED_DATA_SIZE + name.length + extra.length];
-
-      intToLittleEndian(buf, SIGNATURE_OFFSET, SIGNATURE);
-      shortToLittleEndian(buf, VERSION_OFFSET, entry.getVersionNeeded());
-      shortToLittleEndian(buf, FLAGS_OFFSET, entry.getFlags());
-      shortToLittleEndian(buf, METHOD_OFFSET, (short) (entry.getMethod().getValue() & 0xffff));
-      intToLittleEndian(buf, MOD_TIME_OFFSET, unixToDosTime(entry.getTime()));
-      intToLittleEndian(buf, CRC_OFFSET, (int) (entry.getCrc() & 0xffffffff));
-      intToLittleEndian(buf, COMPRESSED_SIZE_OFFSET,
-          (int) (entry.getCompressedSize() & 0xffffffff));
-      intToLittleEndian(buf, UNCOMPRESSED_SIZE_OFFSET, (int) (entry.getSize() & 0xffffffff));
-      shortToLittleEndian(buf, FILENAME_LENGTH_OFFSET, (short) name.length);
-      shortToLittleEndian(buf, EXTRA_FIELD_LENGTH_OFFSET, (short) extra.length);
-      System.arraycopy(name, 0, buf, FIXED_DATA_SIZE, name.length);
-      System.arraycopy(extra, 0, buf, FIXED_DATA_SIZE + name.length, extra.length);
-
-      return buf;
-    }
-  }
-
-  static class CentralDirectoryFileHeader {
-    static final int SIGNATURE = 0x02014b50;
-    static final int FIXED_DATA_SIZE = 46;
-    static final int SIGNATURE_OFFSET = 0;
-    static final int VERSION_OFFSET = 4;
-    static final int VERSION_NEEDED_OFFSET = 6;
-    static final int FLAGS_OFFSET = 8;
-    static final int METHOD_OFFSET = 10;
-    static final int MOD_TIME_OFFSET = 12;
-    static final int CRC_OFFSET = 16;
-    static final int COMPRESSED_SIZE_OFFSET = 20;
-    static final int UNCOMPRESSED_SIZE_OFFSET = 24;
-    static final int FILENAME_LENGTH_OFFSET = 28;
-    static final int EXTRA_FIELD_LENGTH_OFFSET = 30;
-    static final int COMMENT_LENGTH_OFFSET = 32;
-    static final int DISK_START_OFFSET = 34;
-    static final int INTERNAL_ATTRIBUTES_OFFSET = 36;
-    static final int EXTERNAL_ATTRIBUTES_OFFSET = 38;
-    static final int LOCAL_HEADER_OFFSET_OFFSET = 42;
-
-    /**
-     * Reads a {@link ZipFileEntry} from the input stream, using the specified charset to decode the
-     * filename and comment.
-     */
-    static ZipFileEntry read(InputStream in, Charset charset)
-        throws IOException {
-      byte[] fixedSizeData = new byte[FIXED_DATA_SIZE];
-
-      if (in.read(fixedSizeData) != FIXED_DATA_SIZE) {
-        throw new ZipException(
-            "Unexpected end of file while reading Central Directory File Header.");
-      }
-      if (!arrayStartsWith(fixedSizeData, intToLittleEndian(SIGNATURE))) {
-        throw new ZipException(String.format(
-            "Malformed Central Directory File Header; does not start with %08x", SIGNATURE));
-      }
-
-      byte[] name = new byte[getUnsignedShort(fixedSizeData, FILENAME_LENGTH_OFFSET)];
-      byte[] extraField = new byte[getUnsignedShort(fixedSizeData, EXTRA_FIELD_LENGTH_OFFSET)];
-      byte[] comment = new byte[getUnsignedShort(fixedSizeData, COMMENT_LENGTH_OFFSET)];
-
-      if (name.length > 0 && in.read(name) != name.length) {
-        throw new ZipException(
-            "Unexpected end of file while reading Central Directory File Header.");
-      }
-      if (extraField.length > 0 && in.read(extraField) != extraField.length) {
-        throw new ZipException(
-            "Unexpected end of file while reading Central Directory File Header.");
-      }
-      if (comment.length > 0 && in.read(comment) != comment.length) {
-        throw new ZipException(
-            "Unexpected end of file while reading Central Directory File Header.");
-      }
-
-      ZipFileEntry entry = new ZipFileEntry(new String(name, charset));
-      entry.setVersion(get16(fixedSizeData, VERSION_OFFSET));
-      entry.setVersionNeeded(get16(fixedSizeData, VERSION_NEEDED_OFFSET));
-      entry.setFlags(get16(fixedSizeData, FLAGS_OFFSET));
-      entry.setMethod(Compression.fromValue(get16(fixedSizeData, METHOD_OFFSET)));
-      long time = dosToUnixTime(get32(fixedSizeData, MOD_TIME_OFFSET));
-      entry.setTime(isValidInDos(time) ? time : DOS_EPOCH);
-      entry.setCrc(getUnsignedInt(fixedSizeData, CRC_OFFSET));
-      entry.setCompressedSize(getUnsignedInt(fixedSizeData, COMPRESSED_SIZE_OFFSET));
-      entry.setSize(getUnsignedInt(fixedSizeData, UNCOMPRESSED_SIZE_OFFSET));
-      entry.setInternalAttributes(get16(fixedSizeData, INTERNAL_ATTRIBUTES_OFFSET));
-      entry.setExternalAttributes(get32(fixedSizeData, EXTERNAL_ATTRIBUTES_OFFSET));
-      entry.setLocalHeaderOffset(getUnsignedInt(fixedSizeData, LOCAL_HEADER_OFFSET_OFFSET));
-      entry.setExtra(extraField);
-      entry.setComment(new String(comment, charset));
-
-      return entry;
-    }
-
-    /**
-     * Generates the raw byte data of the central directory file header for the ZipEntry. Uses the
-     * specified charset to encode the file name and comment.
-     */
-    static byte[] create(ZipFileEntry entry, Charset charset) {
-      byte[] name = entry.getName().getBytes(charset);
-      byte[] extra = entry.getExtra() != null ? entry.getExtra() : new byte[]{};
-      byte[] comment = entry.getComment() != null
-          ? entry.getComment().getBytes(charset) : new byte[]{};
-
-      byte[] buf = new byte[FIXED_DATA_SIZE + name.length + extra.length + comment.length];
-
-      fillFixedSizeData(buf, entry, name.length, extra.length, comment.length);
-      System.arraycopy(name, 0, buf, FIXED_DATA_SIZE, name.length);
-      System.arraycopy(extra, 0, buf, FIXED_DATA_SIZE + name.length, extra.length);
-      System.arraycopy(comment, 0, buf, FIXED_DATA_SIZE + name.length + extra.length,
-          comment.length);
-
-      return buf;
-    }
-
-    /**
-     * Writes the central directory file header for the ZipEntry to an output stream. Uses the
-     * specified charset to encode the file name and comment.
-     */
-    static int write(ZipFileEntry entry, Charset charset, byte[] buf,
-        OutputStream stream) throws IOException {
-      if (buf == null || buf.length < FIXED_DATA_SIZE) {
-        buf = new byte[FIXED_DATA_SIZE];
-      }
-
-      byte[] name = entry.getName().getBytes(charset);
-      byte[] extra = entry.getExtra() != null ? entry.getExtra() : new byte[]{};
-      byte[] comment = entry.getComment() != null
-          ? entry.getComment().getBytes(charset) : new byte[]{};
-
-      fillFixedSizeData(buf, entry, name.length, extra.length, comment.length);
-      stream.write(buf, 0, FIXED_DATA_SIZE);
-      stream.write(name);
-      stream.write(extra);
-      stream.write(comment);
-
-      return FIXED_DATA_SIZE + name.length + extra.length + comment.length;
-    }
-
-    /**
-     * Write the fixed size data portion for the specified ZIP entry to the buffer.
-     */
-    private static void fillFixedSizeData(byte[] buf, ZipFileEntry entry, int nameLength,
-        int extraLength, int commentLength) {
-      intToLittleEndian(buf, SIGNATURE_OFFSET, SIGNATURE);
-      shortToLittleEndian(buf, VERSION_OFFSET, entry.getVersion());
-      shortToLittleEndian(buf, VERSION_NEEDED_OFFSET, entry.getVersionNeeded());
-      shortToLittleEndian(buf, FLAGS_OFFSET, entry.getFlags());
-      shortToLittleEndian(buf, METHOD_OFFSET, (short) (entry.getMethod().getValue() & 0xffff));
-      intToLittleEndian(buf, MOD_TIME_OFFSET, unixToDosTime(entry.getTime()));
-      intToLittleEndian(buf, CRC_OFFSET, (int) (entry.getCrc() & 0xffffffff));
-      intToLittleEndian(buf, COMPRESSED_SIZE_OFFSET,
-          (int) (entry.getCompressedSize() & 0xffffffff));
-      intToLittleEndian(buf, UNCOMPRESSED_SIZE_OFFSET, (int) (entry.getSize() & 0xffffffff));
-      shortToLittleEndian(buf, FILENAME_LENGTH_OFFSET, (short) (nameLength & 0xffff));
-      shortToLittleEndian(buf, EXTRA_FIELD_LENGTH_OFFSET, (short) (extraLength & 0xffff));
-      shortToLittleEndian(buf, COMMENT_LENGTH_OFFSET, (short) (commentLength & 0xffff));
-      shortToLittleEndian(buf, DISK_START_OFFSET, (short) 0);
-      shortToLittleEndian(buf, INTERNAL_ATTRIBUTES_OFFSET, entry.getInternalAttributes());
-      intToLittleEndian(buf, EXTERNAL_ATTRIBUTES_OFFSET, entry.getExternalAttributes());
-      intToLittleEndian(buf, LOCAL_HEADER_OFFSET_OFFSET,
-          (int) (entry.getLocalHeaderOffset() & 0xffffffff));
-    }
-  }
-
-  static class EndOfCentralDirectoryRecord {
-    static final int SIGNATURE = 0x06054b50;
-    static final int FIXED_DATA_SIZE = 22;
-    static final int SIGNATURE_OFFSET = 0;
-    static final int DISK_NUMBER_OFFSET = 4;
-    static final int CD_DISK_OFFSET = 6;
-    static final int DISK_ENTRIES_OFFSET = 8;
-    static final int TOTAL_ENTRIES_OFFSET = 10;
-    static final int CD_SIZE_OFFSET = 12;
-    static final int CD_OFFSET_OFFSET = 16;
-    static final int COMMENT_LENGTH_OFFSET = 20;
-
-    /**
-     * Generates the raw byte data of the end of central directory record, given the specifics of
-     * the ZIP file.
-     */
-    static byte[] create(long fileOffset, long size, long numEntries, String fileComment,
-        Charset charset) {
-      byte[] comment = fileComment.getBytes(charset);
-
-      byte[] buf = new byte[FIXED_DATA_SIZE + comment.length];
-
-      intToLittleEndian(buf, SIGNATURE_OFFSET, SIGNATURE);
-      shortToLittleEndian(buf, DISK_NUMBER_OFFSET, (short) 0);
-      shortToLittleEndian(buf, CD_DISK_OFFSET, (short) 0);
-      shortToLittleEndian(buf, DISK_ENTRIES_OFFSET, (short) (numEntries & 0xffff));
-      shortToLittleEndian(buf, TOTAL_ENTRIES_OFFSET, (short) (numEntries & 0xffff));
-      intToLittleEndian(buf, CD_SIZE_OFFSET, (int) (size & 0xffffffff));
-      intToLittleEndian(buf, CD_OFFSET_OFFSET, (int) (fileOffset & 0xffffffff));
-      shortToLittleEndian(buf, COMMENT_LENGTH_OFFSET, (short) (comment.length & 0xffff));
-      System.arraycopy(comment, 0, buf, FIXED_DATA_SIZE, comment.length);
-
-      return buf;
-    }
-  }
-
-  static class CentralDirectory {
-
-    /**
-     * Writes the central directory to an output stream, given the specifics of the ZIP file.
-     */
-    static void write(Collection<ZipFileEntry> entries, String fileComment, long fileOffset,
-        Charset charset, OutputStream stream) throws IOException {
-      long directorySize = 0;
-      byte[] buf = new byte[CentralDirectoryFileHeader.FIXED_DATA_SIZE];
-      for (ZipFileEntry entry : entries) {
-        directorySize += CentralDirectoryFileHeader.write(entry, charset, buf, stream);
-      }
-      stream.write(EndOfCentralDirectoryRecord.create(fileOffset, directorySize, entries.size(),
-          fileComment != null ? fileComment : "", charset));
-    }
-  }
-}
diff --git a/src/java_tools/singlejar/java/com/google/devtools/build/zip/ZipWriter.java b/src/java_tools/singlejar/java/com/google/devtools/build/zip/ZipWriter.java
deleted file mode 100644
index ad8eafc5b8..0000000000
--- a/src/java_tools/singlejar/java/com/google/devtools/build/zip/ZipWriter.java
+++ /dev/null
@@ -1,231 +0,0 @@
-// Copyright 2015 Google Inc. All rights reserved.
-//
-// 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 com.google.devtools.build.zip;
-
-import com.google.devtools.build.zip.ZipFileEntry.Flag;
-import com.google.devtools.build.zip.ZipUtil.CentralDirectory;
-import com.google.devtools.build.zip.ZipUtil.LocalFileHeader;
-
-import java.io.IOException;
-import java.io.OutputStream;
-import java.nio.charset.Charset;
-import java.util.LinkedList;
-import java.util.List;
-import java.util.zip.ZipException;
-
-/**
- * This class implements an output stream filter for writing files in the ZIP file format. It does
- * not perform its own compression and so allows writing of already compressed file data.
- */
-public class ZipWriter extends OutputStream {
-  private CountingOutputStream stream;
-  private Charset charset;
-  private String comment;
-  private boolean writingPrefix;
-  private ZipFileEntry entry;
-  private long bytesWritten;
-  private List<ZipFileEntry> entries;
-  private boolean finished;
-
-  /**
-   * Creates a new raw ZIP output stream.
-   *
-   * @param out the actual output stream
-   * @param charset the {@link Charset} to be used to encode the entry names and comments
-   */
-  public ZipWriter(OutputStream out, Charset charset) {
-    this.stream = new CountingOutputStream(out);
-    this.charset = charset;
-    this.entries = new LinkedList<>();
-    this.finished = false;
-  }
-
-  /**
-   * Sets the ZIP file comment.
-   *
-   * @param comment the ZIP file comment
-   */
-  public void setComment(String comment) {
-    this.comment = comment;
-  }
-
-  /**
-   * Configures the stream to write prefix file data.
-   *
-   * @throws ZipException if other contents have already been written to the output stream
-   */
-  public void startPrefixFile() throws ZipException {
-    checkNotFinished();
-    if (!entries.isEmpty() || entry != null) {
-      throw new ZipException("Cannot add a prefix file after the zip contents have been started.");
-    }
-    writingPrefix = true;
-  }
-
-  /** Closes the prefix file and positions the output stream to write ZIP entries. */
-  public void endPrefixFile() {
-    checkNotFinished();
-    writingPrefix = false;
-  }
-
-  /**
-   * Begins writing a new ZIP file entry and positions the stream to the start of the entry data.
-   * Closes the current entry if still active.
-   *
-   * <p><em>NOTE:</em> No defensive copying is performed on e. The local header offset and flags
-   * will be modified.
-   *
-   * @param e the ZIP entry to be written
-   * @throws IOException if an I/O error occurred
-   */
-  public void putNextEntry(ZipFileEntry e) throws IOException {
-    checkNotFinished();
-    writingPrefix = false;
-    if (entry != null) {
-      finishEntry();
-    }
-    startEntry(e);
-  }
-
-  /**
-   * Closes the current ZIP entry and positions the stream for writing the next entry.
-   *
-   * @throws ZipException if a ZIP format exception occurred
-   * @throws IOException if an I/O error occurred
-   */
-  public void closeEntry() throws IOException {
-    checkNotFinished();
-    if (entry != null) {
-      finishEntry();
-    }
-  }
-
-  @Override public void write(int b) throws IOException {
-    byte[] buf = new byte[1];
-    buf[0] = (byte) (b & 0xff);
-    write(buf);
-  }
-
-  @Override public void write(byte[] b) throws IOException {
-    write(b, 0, b.length);
-  }
-
-  @Override public synchronized void write(byte[] b, int off, int len) throws IOException {
-    checkNotFinished();
-    if (entry == null && !writingPrefix) {
-      throw new ZipException("Cannot write zip contents without first setting a ZipEntry or"
-          + " starting a prefix file.");
-    }
-    stream.write(b, off, len);
-    bytesWritten += len;
-  }
-
-  /**
-   * Finishes writing the contents of the ZIP output stream without closing the underlying stream.
-   * Use this method when applying multiple filters in succession to the same output stream.
-   *
-   * @throws ZipException if a ZIP file error has occurred
-   * @throws IOException if an I/O exception has occurred
-   */
-  public void finish() throws IOException {
-    checkNotFinished();
-    if (entry != null) {
-      finishEntry();
-    }
-    writeCentralDirectory();
-    finished = true;
-  }
-
-  @Override public void close() throws IOException {
-    if (!finished) {
-      finish();
-    }
-    stream.close();
-  }
-
-  /**
-   * Writes the local file header for the ZIP entry and positions the stream to the start of the
-   * entry data.
-   *
-   * @param e the ZIP entry for which to write the local file header
-   * @throws ZipException if a ZIP file error has occurred
-   * @throws IOException if an I/O exception has occurred
-   */
-  private void startEntry(ZipFileEntry e) throws IOException {
-    if (e.getName() == null) {
-      throw new IllegalArgumentException("Zip entry name must not be null");
-    }
-    if (e.getTime() == -1) {
-      throw new IllegalArgumentException("Zip entry last modified time must be set");
-    }
-    if (e.getCrc() == -1) {
-      throw new IllegalArgumentException("Zip entry CRC-32 must be set");
-    }
-    if (e.getSize() == -1) {
-      throw new IllegalArgumentException("Zip entry uncompressed size must be set");
-    }
-    if (e.getCompressedSize() == -1) {
-      throw new IllegalArgumentException("Zip entry compressed size must be set");
-    }
-    if (e.getMethod() == null) {
-      throw new IllegalArgumentException("Zip entry compression method must not be null");
-    }
-    if (e.getVersion() == -1) {
-      throw new IllegalArgumentException("Zip entry version made by must be set");
-    }
-    if (e.getVersionNeeded() == -1) {
-      throw new IllegalArgumentException("Zip entry version needed must be set");
-    }
-    bytesWritten = 0;
-    entry = e;
-    entry.setFlag(Flag.DATA_DESCRIPTOR, false);
-    entry.setLocalHeaderOffset(stream.getCount());
-    stream.write(LocalFileHeader.create(entry, charset));
-  }
-
-  /**
-   * Closes the current ZIP entry and positions the stream for writing the next entry. Checks that
-   * the amount of data written matches the compressed size indicated by the ZipEntry.
-   *
-   * @throws ZipException if a ZIP file error has occurred
-   * @throws IOException if an I/O exception has occurred
-   */
-  private void finishEntry() throws IOException {
-    if (entry.getCompressedSize() != bytesWritten) {
-      throw new ZipException(String.format("Number of bytes written for the entry %s (%d) does not"
-          + " match the reported compressed size (%d).", entry.getName(), bytesWritten,
-          entry.getCompressedSize()));
-    }
-    entries.add(entry);
-    entry = null;
-  }
-
-  /**
-   * Writes the ZIP file's central directory.
-   *
-   * @throws ZipException if a ZIP file error has occurred
-   * @throws IOException if an I/O exception has occurred
-   */
-  private void writeCentralDirectory() throws IOException {
-    CentralDirectory.write(entries, comment, stream.getCount(), charset, stream);
-  }
-
-  /** Checks that the ZIP file has not been finished yet. */
-  private void checkNotFinished() {
-    if (finished) {
-      throw new IllegalStateException();
-    }
-  }
-}