Class ElfZipFileChannel

java/com/facebook/soloader/ElfZipFileChannel.java:26–159

import javax.annotation.Nullable;

public class ElfZipFileChannel implements ElfByteChannel {

  private @Nullable InputStream mIs;
  private final ZipEntry mZipEntry;
  private final ZipFile mZipFile;
  private final long mLength;
  private boolean mOpened;
  private long mPos;

  public ElfZipFileChannel(ZipFile zipFile, ZipEntry zipEntry) throws IOException {
    mZipFile = zipFile;
    mZipEntry = zipEntry;

    mOpened = true;
    mPos = 0;
    mLength = mZipEntry.getSize();
    mIs = mZipFile.getInputStream(mZipEntry);
    if (mIs == null) {
      throw new IOException(mZipEntry.getName() + "'s InputStream is null");
    }
  }

  @Override
  public long position() throws IOException {
    return mPos;
  }

  @Override
  public ElfByteChannel position(long newPosition) throws IOException {
    if (mIs == null) {
      throw new IOException(mZipEntry.getName() + "'s InputStream is null");
    }

    if (newPosition == mPos) {
      return this;
    }

    if (newPosition > mLength) {
      newPosition = mLength;
    }
    if (newPosition >= mPos) {
      mIs.skip(newPosition - mPos);
    } else {
      mIs.close();
      mIs = mZipFile.getInputStream(mZipEntry);
      if (mIs == null) {
        throw new IOException(mZipEntry.getName() + "'s InputStream is null");
      }
      mIs.skip(newPosition);
    }
    mPos = newPosition;
    return this;
  }

  /**
   * Reads a sequence of bytes from this channel into the given buffer. Bytes are read starting at
   * this channel's current file position, and then the file position is updated with the number of
   * bytes actually read.