java.io.InputStream#mark ( )源码实例Demo

/**
 * Makes sure that the header bytes are copied when creating a new buffer
 * to hold all the required bytes when the stream has been marked.
 * This will only happen the first time the buffer is filled, i.e. when the
 * stream is marked before the first read (mark at position zero).
 *
 * @throws IOException if something goes wrong
 */
public void testHeaderPresentInStream_Internal()
        throws IOException {
    final int valueLen = DEFAULT_INTERNAL_BUFFER_SIZE + 5*1024;
    InputStream is = getStream(valueLen);
    is.mark(valueLen - 1024);
    // Obtain a header generator to compare with.
    ClobStreamHeaderGenerator hdrGen = new ClobStreamHeaderGenerator(false);
    byte[] hdrTmp = new byte[100];
    int headerLen = hdrGen.generateInto(hdrTmp, 0, valueLen);
    byte[] hdr1 = new byte[headerLen];
    System.arraycopy(hdrTmp, 0, hdr1, 0, headerLen);
    byte[] hdr2 = new byte[headerLen];
    // Get the first bytes from the stream being tested.
    assertEquals(headerLen, is.read(hdr2));
    assertEquals(new ByteArrayInputStream(hdr1),
                 new ByteArrayInputStream(hdr2));
}
 

/** Load lua source or lua binary from an input stream into a Prototype. 
 * The InputStream is either a binary lua chunk starting with the lua binary chunk signature, 
 * or a text input file.  If it is a text input file, it is interpreted as a UTF-8 byte sequence.  
 * @param is Input stream containing a lua script or compiled lua"
 * @param chunkname Name that will be used within the chunk as the source.
 * @param mode String containing 'b' or 't' or both to control loading as binary or text or either.
 */
public Prototype loadPrototype(InputStream is, String chunkname, String mode) throws IOException {
	if (mode.indexOf('b') >= 0) {
		if (undumper == null)
			error("No undumper.");
		if (!is.markSupported())
			is = new BufferedStream(is);
		is.mark(4);
		final Prototype p = undumper.undump(is, chunkname);
		if (p != null)
			return p;
		is.reset();
	}
	if (mode.indexOf('t') >= 0) {
		return compilePrototype(is, chunkname);
	}
	error("Failed to load prototype "+chunkname+" using mode '"+mode+"'");
	return null;
}
 

private void testMarkAndReset(TransferKind transferKind) throws IOException {
    MockResponse response = new MockResponse();
    transferKind.setBody(response, "ABCDEFGHIJKLMNOPQRSTUVWXYZ", 1024);
    server.enqueue(response);
    server.enqueue(response);
    server.play();

    InputStream in = server.getUrl("/").openConnection().getInputStream();
    assertFalse("This implementation claims to support mark().", in.markSupported());
    in.mark(5);
    assertEquals("ABCDE", readAscii(in, 5));
    try {
        in.reset();
        fail();
    } catch (IOException expected) {
    }
    assertEquals("FGHIJKLMNOPQRSTUVWXYZ", readAscii(in, Integer.MAX_VALUE));
    assertContent("ABCDEFGHIJKLMNOPQRSTUVWXYZ", server.getUrl("/").openConnection());
}
 

private FeedReader createFeedReader(InputStream in) throws Exception {
    in.mark(8);
    byte [] b = new byte[2];
    int numRead = readExact(in, b);
    in.reset();
    if (numRead != b.length) {
        throw new IllegalArgumentException("Need to read " + b.length + " bytes to detect format. Got " + numRead + " bytes.");
    }
    if (b[0] == '[') {
        return new JsonFeedReader(in, docTypeMgr);
    } else if ((b[0] == 'V') && (b[1] == '1')) {
        return new VespaV1FeedReader(in, docTypeMgr);
    } else {
         return new VespaXMLFeedReader(in, docTypeMgr);
    }
}
 

/**
 * XMLEntityManager cares about endian-ness, since it creates its own optimized
 * readers. Since we're just using generic Java readers for now, we're not caring
 * about endian-ness.  If this changes, even more code needs to be copied from
 * XMLEntity manager. -- PJM
 */
protected String getEncodingName(InputStream stream) throws IOException {
    final byte[] b4 = new byte[4];
    String encoding = null;

    // this has the potential to throw an exception
    // it will be fixed when we ensure the stream is rewindable (see note above)
    stream.mark(4);
    int count = stream.read(b4, 0, 4);
    stream.reset();
    if (count == 4) {
        encoding = getEncodingName(b4);
    }

    return encoding;
}
 

public void testNewInput_skip() throws IOException {
  InputStream input = stringUnderTest.newInput();
  int stringSize = stringUnderTest.size();
  int nearEndIndex = stringSize * 2 / 3;
  long skipped1 = input.skip(nearEndIndex);
  assertEquals("InputStream.skip()", skipped1, nearEndIndex);
  assertEquals("InputStream.available()",
      stringSize - skipped1, input.available());
  assertTrue("InputStream.mark() is available", input.markSupported());
  input.mark(0);
  assertEquals("InputStream.skip(), read()",
      stringUnderTest.byteAt(nearEndIndex) & 0xFF, input.read());
  assertEquals("InputStream.available()",
               stringSize - skipped1 - 1, input.available());
  long skipped2 = input.skip(stringSize);
  assertEquals("InputStream.skip() incomplete",
      skipped2, stringSize - skipped1 - 1);
  assertEquals("InputStream.skip(), no more input", 0, input.available());
  assertEquals("InputStream.skip(), no more input", -1, input.read());
  input.reset();
  assertEquals("InputStream.reset() succeded",
               stringSize - skipped1, input.available());
  assertEquals("InputStream.reset(), read()",
      stringUnderTest.byteAt(nearEndIndex) & 0xFF, input.read());
}
 

private SortedMap parseDictionary(InputStream is) throws IOException {
    SortedMap<ByteBuffer, Object> map = new TreeMap<ByteBuffer, Object>(new DictionaryComparator());
    is.mark(0);
    int readChar = is.read();
    while (readChar != 'e') {
        if (readChar < 0) {
            throw new IOException("Unexpected EOF found");
        }
        is.reset();
        map.put(parseByteString(is), parse(is));
        is.mark(0);
        readChar = is.read();
    }

    return map;
}
 

public static final MidiEvent parseEvent(long tick, long delta, InputStream in) throws IOException
{
    in.mark(1);
    boolean reset = false;

    int id = in.read();
    if(!verifyIdentifier(id))
    {
        in.reset();
        reset = true;
    }

    if(sType >= 0x8 && sType <= 0xE)
    {
        return ChannelEvent.parseChannelEvent(tick, delta, sType, sChannel, in);
    }
    else if(sId == 0xFF)
    {
        return MetaEvent.parseMetaEvent(tick, delta, in);
    }
    else if(sId == 0xF0 || sId == 0xF7)
    {
        VariableLengthInt size = new VariableLengthInt(in);
        byte[] data = new byte[size.getValue()];
        in.read(data);
        return new SystemExclusiveEvent(sId, tick, delta, data);
    }
    else
    {
        System.out.println("Unable to handle status byte, skipping: " + sId);
        if(reset)
        {
            in.read();
        }
    }

    return null;
}
 

/**
 * Tries to read a data model version using each VersionedSerializer, in descending version order.
 * If no version could be read from any serializer, then a SerializationException is thrown.
 *
 * When deserializing, clients are expected to call this method to obtain the version, then call
 * {@method isProcessGroupVersion}, which then determines if {@method deserializeProcessGroup}
 * should be used, or if {@method deserializeFlowContent} should be used.
 *
 * @param input the input stream containing serialized flow content
 * @return the data model version from the input stream
 * @throws SerializationException if the data model version could not be read with any serializer
 */
public int readDataModelVersion(final InputStream input) throws SerializationException {
    final InputStream markSupportedInput = input.markSupported() ? input : new BufferedInputStream(input);

    // Mark the beginning of the stream.
    markSupportedInput.mark(SerializationConstants.MAX_HEADER_BYTES);

    // Try each serializer in descending version order
    for (final int serializerVersion : descendingVersions) {
        final VersionedSerializer<?> serializer = allSerializers.get(serializerVersion);
        try {
            return serializer.readDataModelVersion(markSupportedInput);
        } catch (SerializationException e) {
            if (logger.isDebugEnabled()) {
                logger.error("Unable to read the data model version due to: {}", e.getMessage());
            }
            continue;
        } finally {
            // Reset the stream position.
            try {
                markSupportedInput.reset();
            } catch (IOException resetException) {
                // Should not happen.
                logger.error("Unable to reset the input stream.", resetException);
            }
        }
    }

    throw new SerializationException("Unable to read the data model version for the flow content.");
}
 

public AudioFileFormat getAudioFileFormat(InputStream stream)
        throws UnsupportedAudioFileException, IOException {

    stream.mark(200);
    AudioFileFormat format;
    try {
        format = internal_getAudioFileFormat(stream);
    } finally {
        stream.reset();
    }
    return format;
}
 

/**
 * Tests an implementation specific feature of ReaderToUTF8Stream, which is
 * that the mark isn't invalidated even though we read past the read ahead
 * limit, given that the internal buffer doesn't have to be refilled.
 * <p>
 * <em>WARNING</em>:This implementation specific feature should not be
 * relied on by the production code! It may change at any time.
 *
 * @throws IOException if something goes wrong
 */
public void testMarkResetExceedReadAheadLimitOK_Internal()
        throws IOException {
    InputStream is = getStream(4*1024+17);
    is.mark(10);
    assertEquals(20, is.read(new byte[20]));
    // Note the following is implementation dependent.
    // Since the bytes are already stored in the internal buffer, we won't
    // fail the reset even though we have exceeded the read ahead limit.
    // With a different stream implementation, this may fail!
    is.reset();
}
 

/**
 * Get the UTrie version from an InputStream containing the serialized form
 * of either a Trie (version 1) or a Trie2 (version 2).
 *
 * @param is   an InputStream containing the serialized form
 *             of a UTrie, version 1 or 2.  The stream must support mark() and reset().
 *             The position of the input stream will be left unchanged.
 * @param littleEndianOk If FALSE, only big-endian (Java native) serialized forms are recognized.
 *                    If TRUE, little-endian serialized forms are recognized as well.
 * @return     the Trie version of the serialized form, or 0 if it is not
 *             recognized as a serialized UTrie
 * @throws     IOException on errors in reading from the input stream.
 */
public static int getVersion(InputStream is, boolean littleEndianOk) throws IOException {
    if (! is.markSupported()) {
        throw new IllegalArgumentException("Input stream must support mark().");
        }
    is.mark(4);
    byte sig[] = new byte[4];
    int read = is.read(sig);
    is.reset();

    if (read != sig.length) {
        return 0;
    }

    if (sig[0]=='T' && sig[1]=='r' && sig[2]=='i' && sig[3]=='e') {
        return 1;
    }
    if (sig[0]=='T' && sig[1]=='r' && sig[2]=='i' && sig[3]=='2') {
        return 2;
    }
    if (littleEndianOk) {
        if (sig[0]=='e' && sig[1]=='i' && sig[2]=='r' && sig[3]=='T') {
            return 1;
        }
        if (sig[0]=='2' && sig[1]=='i' && sig[2]=='r' && sig[3]=='T') {
            return 2;
        }
    }
    return 0;
}
 

protected boolean isData(final InputStream in) throws IOException {
    in.mark(1);
    final int nextByte = in.read();
    in.reset();

    return nextByte > -1;
}
 

private static boolean isMoreData(final InputStream in) throws IOException {
    in.mark(1);
    final int nextByte = in.read();
    if (nextByte == -1) {
        return false;
    }

    in.reset();
    return true;
}
 

public Soundbank getSoundbank(InputStream stream)
        throws InvalidMidiDataException, IOException {
    try {
        stream.mark(512);
        return new DLSSoundbank(stream);
    } catch (RIFFInvalidFormatException e) {
        stream.reset();
        return null;
    }
}
 

public Soundbank getSoundbank(InputStream stream)
        throws InvalidMidiDataException, IOException {
    try {
        stream.mark(512);
        return new SF2Soundbank(stream);
    } catch (RIFFInvalidFormatException e) {
        stream.reset();
        return null;
    }
}
 

public static AudioFileFormat getAudioFileFormat(InputStream is) throws
    UnsupportedAudioFileException, IOException
{
  try
  {
    //return AudioSystem.getAudioFileFormat(is);
    throw new Exception();
  }
  catch (Exception iae)
  {
    if (DEBUG == true)
    {
      System.err.println("Using AppletVorbisSPIWorkaround to get codec");
    }
    try
    {
      // 2.2 Fix.
      is.mark(4096);
      //Class.forName("javazoom.spi.vorbis.sampled.file.VorbisAudioFileReader");
      Class.forName("org.tritonus.sampled.file.jorbis.JorbisAudioFileReader");
      //return new javazoom.spi.vorbis.sampled.file.VorbisAudioFileReader().
      return new org.tritonus.sampled.file.jorbis.JorbisAudioFileReader().
          getAudioFileFormat(is);
    }
    catch (ClassNotFoundException cnfe)
    {
      throw new IllegalArgumentException(
          "Vorbis codec not properly installed");
    }
  }
  // 2.2 Fix.
  finally
  {
    is.reset();
  }
}
 

@Override
public void readFrom(InputStream in) throws IOException {
  // Skip data type byte (we assume it's already read)
  size = 1;
  InputStream markInputStream = in.markSupported() ? in : new BufferedInputStream(in);

  while (true) {
    // Look for the 3-byte object end marker [0x00 0x00 0x09]
    markInputStream.mark(3);
    byte[] endMarker = new byte[3];
    markInputStream.read(endMarker);

    if (endMarker[0] == OBJECT_END_MARKER[0]
        && endMarker[1] == OBJECT_END_MARKER[1]
        && endMarker[2] == OBJECT_END_MARKER[2]) {
      // End marker found
      size += 3;
      return;
    } else {
      // End marker not found; reset the stream to the marked position and read an AMF property
      markInputStream.reset();
      // Read the property key...
      String key = AmfString.readStringFrom(in, true);
      size += AmfString.sizeOf(key, true);
      // ...and the property value
      AmfData value = AmfDecoder.readFrom(markInputStream);
      size += value.getSize();
      properties.put(key, value);
    }
  }
}
 

/**
 * 
 * Determines the size of an input stream, and optionally calculates the MD5 hash for the stream.
 * 
 * @param sourceStream
 *            A <code>InputStream</code> object that represents the stream to measure.
 * @param writeLength
 *            The number of bytes to read from the stream.
 * @param abandonLength
 *            The number of bytes to read before the analysis is abandoned. Set this value to <code>-1</code> to
 *            force the entire stream to be read. This parameter is provided to support upload thresholds.
 * @param rewindSourceStream
 *            <code>true</code> if the stream should be rewound after it is read; otherwise, <code>false</code>.
 * @param calculateMD5
 *            <code>true</code> if an MD5 hash will be calculated; otherwise, <code>false</code>.
 * 
 * @return A {@link StreamMd5AndLength} object that contains the stream length, and optionally the MD5 hash.
 * 
 * @throws IOException
 *             If an I/O error occurs.
 * @throws StorageException
 *             If a storage service error occurred.
 */
public static StreamMd5AndLength analyzeStream(final InputStream sourceStream, long writeLength,
        long abandonLength, final boolean rewindSourceStream, final boolean calculateMD5) throws IOException,
        StorageException {
    if (abandonLength < 0) {
        abandonLength = Long.MAX_VALUE;
    }

    if (rewindSourceStream) {
        if (!sourceStream.markSupported()) {
            throw new IllegalArgumentException(SR.INPUT_STREAM_SHOULD_BE_MARKABLE);
        }

        sourceStream.mark(Constants.MAX_MARK_LENGTH);
    }

    MessageDigest digest = null;
    if (calculateMD5) {
        try {
            digest = MessageDigest.getInstance("MD5");
        }
        catch (final NoSuchAlgorithmException e) {
            // This wont happen, throw fatal.
            throw Utility.generateNewUnexpectedStorageException(e);
        }
    }

    if (writeLength < 0) {
        writeLength = Long.MAX_VALUE;
    }

    final StreamMd5AndLength retVal = new StreamMd5AndLength();
    int count = -1;
    final byte[] retrievedBuff = new byte[Constants.BUFFER_COPY_LENGTH];

    int nextCopy = (int) Math.min(retrievedBuff.length, writeLength - retVal.getLength());
    count = sourceStream.read(retrievedBuff, 0, nextCopy);

    while (nextCopy > 0 && count != -1) {
        if (calculateMD5) {
            digest.update(retrievedBuff, 0, count);
        }
        retVal.setLength(retVal.getLength() + count);

        if (retVal.getLength() > abandonLength) {
            // Abandon operation
            retVal.setLength(-1);
            retVal.setMd5(null);
            break;
        }

        nextCopy = (int) Math.min(retrievedBuff.length, writeLength - retVal.getLength());
        count = sourceStream.read(retrievedBuff, 0, nextCopy);
    }

    if (retVal.getLength() != -1 && calculateMD5) {
        retVal.setMd5(Base64.encode(digest.digest()));
    }

    if (retVal.getLength() != -1 && writeLength > 0) {
        retVal.setLength(Math.min(retVal.getLength(), writeLength));
    }

    if (rewindSourceStream) {
        sourceStream.reset();
        sourceStream.mark(Constants.MAX_MARK_LENGTH);
    }

    return retVal;
}
 

/**
 * Uploads a blob in a single operation.
 *
 * @param sourceStream
 *            A <code>InputStream</code> object that represents the source stream to upload.
 * @param length
 *            The length, in bytes, of the stream, or -1 if unknown.
 * @param accessCondition
 *            An {@link AccessCondition} object that represents the access conditions for the blob.
 * @param options
 *            A {@link BlobRequestOptions} object that specifies any additional options for the request. Specifying
 *            <code>null</code> will use the default request options from the associated service client (
 *            {@link CloudBlobClient}).
 * @param opContext
 *            An {@link OperationContext} object that represents the context for the current operation. This object
 *            is used to track requests to the storage service, and to provide additional runtime information about
 *            the operation.
 * @throws StorageException
 *             If a storage service error occurred.
 */
@DoesServiceRequest
protected final void uploadFullBlob(final InputStream sourceStream, final long length,
        final AccessCondition accessCondition, final BlobRequestOptions options, final OperationContext opContext)
        throws StorageException {
    assertNoWriteOperationForSnapshot();

    // Mark sourceStream for current position.
    sourceStream.mark(Constants.MAX_MARK_LENGTH);

    if (length < 0 || length > BlobConstants.MAX_SINGLE_UPLOAD_BLOB_SIZE_IN_BYTES) {
        throw new IllegalArgumentException(String.format(SR.INVALID_STREAM_LENGTH,
                BlobConstants.MAX_SINGLE_UPLOAD_BLOB_SIZE_IN_BYTES / Constants.MB));
    }

    ExecutionEngine.executeWithRetry(this.blobServiceClient, this,
            uploadFullBlobImpl(sourceStream, length, accessCondition, options, opContext),
            options.getRetryPolicyFactory(), opContext);
}