コード例 #1
1
ファイル: MapTest.java プロジェクト: FauxFaux/jdk9-jdk
  /**
   * Maps blah file with a random offset and checks to see if read from the ByteBuffer gets the
   * right line number
   */
  private static void testRead() throws Exception {
    StringBuilder sb = new StringBuilder();
    sb.setLength(4);

    for (int x = 0; x < 1000; x++) {
      try (FileInputStream fis = new FileInputStream(blah)) {
        FileChannel fc = fis.getChannel();

        long offset = generator.nextInt(10000);
        long expectedResult = offset / CHARS_PER_LINE;
        offset = expectedResult * CHARS_PER_LINE;

        MappedByteBuffer b = fc.map(MapMode.READ_ONLY, offset, 100);

        for (int i = 0; i < 4; i++) {
          byte aByte = b.get(i);
          sb.setCharAt(i, (char) aByte);
        }

        int result = Integer.parseInt(sb.toString());
        if (result != expectedResult) {
          err.println("I expected " + expectedResult);
          err.println("I got " + result);
          throw new Exception("Read test failed");
        }
      }
    }
  }
コード例 #2
1
ファイル: MapTest.java プロジェクト: FauxFaux/jdk9-jdk
  /**
   * Maps blah file with a random offset and checks to see if data written out to the file can be
   * read back in
   */
  private static void testWrite() throws Exception {
    StringBuilder sb = new StringBuilder();
    sb.setLength(4);

    for (int x = 0; x < 1000; x++) {
      try (RandomAccessFile raf = new RandomAccessFile(blah, "rw")) {
        FileChannel fc = raf.getChannel();

        long offset = generator.nextInt(1000);
        MappedByteBuffer b = fc.map(MapMode.READ_WRITE, offset, 100);

        for (int i = 0; i < 4; i++) {
          b.put(i, (byte) ('0' + i));
        }

        for (int i = 0; i < 4; i++) {
          byte aByte = b.get(i);
          sb.setCharAt(i, (char) aByte);
        }
        if (!sb.toString().equals("0123")) throw new Exception("Write test failed");
      }
    }
  }
コード例 #3
0
ファイル: UseCharsets.java プロジェクト: clonegod/app-samples
  public static void main(String args[]) throws Exception {
    String inputFile = "samplein.txt";
    String outputFile = "sampleout.txt";

    RandomAccessFile inf = new RandomAccessFile(inputFile, "r");
    RandomAccessFile outf = new RandomAccessFile(outputFile, "rw");
    long inputLength = new File(inputFile).length();

    FileChannel inc = inf.getChannel();
    FileChannel outc = outf.getChannel();

    MappedByteBuffer inputData = inc.map(FileChannel.MapMode.READ_ONLY, 0, inputLength);

    Charset latin1 = Charset.forName("ISO-8859-1");
    CharsetDecoder decoder = latin1.newDecoder();
    CharsetEncoder encoder = latin1.newEncoder();

    CharBuffer cb = decoder.decode(inputData);

    // Process char data here

    ByteBuffer outputData = encoder.encode(cb);

    outc.write(outputData);

    inf.close();
    outf.close();
  }
コード例 #4
0
ファイル: MapTest.java プロジェクト: FauxFaux/jdk9-jdk
 /**
  * Checks that FileChannel map throws one of the expected exceptions when invoked with the given
  * inputs.
  */
 private static void checkException(
     FileChannel fc, MapMode mode, long position, long size, Class<?>... expected)
     throws IOException {
   Exception exc = null;
   try {
     fc.map(mode, position, size);
   } catch (Exception actual) {
     exc = actual;
   }
   if (exc != null) {
     for (Class<?> clazz : expected) {
       if (clazz.isInstance(exc)) {
         return;
       }
     }
   }
   System.err.println("Expected one of");
   for (Class<?> clazz : expected) {
     System.out.println(clazz);
   }
   if (exc == null) {
     throw new RuntimeException("No expection thrown");
   } else {
     throw new RuntimeException("Unexpected exception thrown", exc);
   }
 }
コード例 #5
0
 public static void main(String[] args) throws Exception {
   fc = new RandomAccessFile("test.dat", "rw").getChannel();
   MappedByteBuffer out = fc.map(FileChannel.MapMode.READ_WRITE, 0, LENGTH);
   for (int i = 0; i < LENGTH; i++) out.put((byte) 'x');
   new LockAndModify(out, 0, 0 + LENGTH / 3);
   new LockAndModify(out, LENGTH / 2, LENGTH / 2 + LENGTH / 4);
 }
コード例 #6
0
  /**
   * Creates and initializes an SPV block store. Will create the given file if it's missing. This
   * operation will block on disk.
   */
  public SPVBlockStore(NetworkParameters params, File file) throws BlockStoreException {
    checkNotNull(file);
    this.params = checkNotNull(params);
    try {
      this.numHeaders = DEFAULT_NUM_HEADERS;
      boolean exists = file.exists();
      // Set up the backing file.
      randomAccessFile = new RandomAccessFile(file, "rw");
      long fileSize = getFileSize();
      if (!exists) {
        log.info("Creating new SPV block chain file " + file);
        randomAccessFile.setLength(fileSize);
      } else if (randomAccessFile.length() != fileSize) {
        throw new BlockStoreException(
            "File size on disk does not match expected size: "
                + randomAccessFile.length()
                + " vs "
                + fileSize);
      }

      FileChannel channel = randomAccessFile.getChannel();
      fileLock = channel.tryLock();
      if (fileLock == null)
        throw new BlockStoreException("Store file is already locked by another process");

      // Map it into memory read/write. The kernel will take care of flushing writes to disk at the
      // most
      // efficient times, which may mean that until the map is deallocated the data on disk is
      // randomly
      // inconsistent. However the only process accessing it is us, via this mapping, so our own
      // view will
      // always be correct. Once we establish the mmap the underlying file and channel can go away.
      // Note that
      // the details of mmapping vary between platforms.
      buffer = channel.map(FileChannel.MapMode.READ_WRITE, 0, fileSize);

      // Check or initialize the header bytes to ensure we don't try to open some random file.
      byte[] header;
      if (exists) {
        header = new byte[4];
        buffer.get(header);
        if (!new String(header, "US-ASCII").equals(HEADER_MAGIC))
          throw new BlockStoreException("Header bytes do not equal " + HEADER_MAGIC);
      } else {
        initNewStore(params);
      }
    } catch (Exception e) {
      try {
        if (randomAccessFile != null) randomAccessFile.close();
      } catch (IOException e2) {
        throw new BlockStoreException(e2);
      }
      throw new BlockStoreException(e);
    }
  }
コード例 #7
0
ファイル: MapTest.java プロジェクト: FauxFaux/jdk9-jdk
  private static void testHighOffset() throws Exception {
    StringBuilder sb = new StringBuilder();
    sb.setLength(4);

    for (int x = 0; x < 1000; x++) {
      try (RandomAccessFile raf = new RandomAccessFile(blah, "rw")) {
        FileChannel fc = raf.getChannel();
        long offset = 66000;
        MappedByteBuffer b = fc.map(MapMode.READ_WRITE, offset, 100);
      }
    }
  }
コード例 #8
0
  /**
   * Read the contents of a text file using a memory-mapped byte buffer.
   *
   * <p>A MappedByteBuffer, is simply a special ByteBuffer. MappedByteBuffer maps a region of a file
   * directly in memory. Typically, that region comprises the entire file, although it could map a
   * portion. You must, therefore, specify what part of the file to map. Moreover, as with the other
   * Buffer objects, no constructor exists; you must ask the java.nio.channels.FileChannel for its
   * map() method to get a MappedByteBuffer.
   *
   * <p>Direct buffers allocate their data directly in the runtime environment memory, bypassing the
   * JVM|OS boundary, usually doubling file copy speed. However, they generally cost more to
   * allocate.
   */
  private static String fastStreamCopy(String filename) {
    String s = "";
    FileChannel fc = null;
    try {
      fc = new FileInputStream(filename).getChannel();

      // int length = (int)fc.size();

      MappedByteBuffer byteBuffer = fc.map(FileChannel.MapMode.READ_ONLY, 0, fc.size());
      // CharBuffer charBuffer =
      // Charset.forName("ISO-8859-1").newDecoder().decode(byteBuffer);

      // ByteBuffer byteBuffer = ByteBuffer.allocate(length);
      // ByteBuffer byteBuffer = ByteBuffer.allocateDirect(length);
      // CharBuffer charBuffer = byteBuffer.asCharBuffer();

      // CharBuffer charBuffer =
      // ByteBuffer.allocateDirect(length).asCharBuffer();
      /*
       * int size = charBuffer.length(); if (size > 0) { StringBuffer sb =
       * new StringBuffer(size); for (int count=0; count<size; count++)
       * sb.append(charBuffer.get()); s = sb.toString(); }
       *
       * if (length > 0) { StringBuffer sb = new StringBuffer(length); for
       * (int count=0; count<length; count++) {
       * sb.append(byteBuffer.get()); } s = sb.toString(); }
       */
      int size = byteBuffer.capacity();
      if (size > 0) {
        // Retrieve all bytes in the buffer
        byteBuffer.clear();
        byte[] bytes = new byte[size];
        byteBuffer.get(bytes, 0, bytes.length);
        s = new String(bytes);
      }

      fc.close();
    } catch (FileNotFoundException fnfx) {
      System.err.println("File not found: " + fnfx);
    } catch (IOException iox) {
      System.err.println("I/O problems: " + iox);
    } finally {
      if (fc != null) {
        try {
          fc.close();
        } catch (IOException ignore) {
          // ignore
        }
      }
    }
    return s;
  }
コード例 #9
0
  public static long checksumMappedFile(Path filename) throws IOException {
    try (FileChannel channel = FileChannel.open(filename)) {
      CRC32 crc = new CRC32();
      int length = (int) channel.size();
      MappedByteBuffer buffer = channel.map(FileChannel.MapMode.READ_ONLY, 0, length);

      for (int p = 0; p < length; p++) {
        int c = buffer.get(p);
        crc.update(c);
      }
      return crc.getValue();
    }
  }
コード例 #10
0
ファイル: DDSImage.java プロジェクト: shamanDevel/shaman.rpg
 private void readFromFile(File file) throws IOException {
   fis = new FileInputStream(file);
   chan = fis.getChannel();
   ByteBuffer buf = chan.map(FileChannel.MapMode.READ_ONLY, 0, (int) file.length());
   readFromBuffer(buf);
 }
コード例 #11
0
ファイル: MapTest.java プロジェクト: FauxFaux/jdk9-jdk
 /** Tests zero size file mapping */
 private static void testZero() throws Exception {
   try (FileInputStream fis = new FileInputStream(blah)) {
     FileChannel fc = fis.getChannel();
     MappedByteBuffer b = fc.map(MapMode.READ_ONLY, 0, 0);
   }
 }