Example usage for java.nio.channels SeekableByteChannel read

List of usage examples for java.nio.channels SeekableByteChannel read

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Introduction

In this page you can find the example usage for java.nio.channels SeekableByteChannel read.

Prototype

@Override
int read(ByteBuffer dst) throws IOException;

Source Link

Document

Reads a sequence of bytes from this channel into the given buffer.

Usage

From source file:Main.java

public static void readData(SeekableByteChannel seekableChannel, Charset cs) throws IOException {
    ByteBuffer byteBuffer = ByteBuffer.allocate(128);
    String encoding = System.getProperty("file.encoding");
    while (seekableChannel.read(byteBuffer) > 0) {
        byteBuffer.rewind();//from w  w  w  . j  a  va 2 s .  c o m
        CharBuffer charBuffer = cs.decode(byteBuffer);
        System.out.print(charBuffer);
        byteBuffer.flip();
    }
}

From source file:internal.diff.aws.service.AmazonS3ETagFileChecksumServiceImpl.java

@Override
public String calculateChecksum(Path file) throws IOException {

    long fileSize = Files.size(file);

    int parts = (int) (fileSize / S3_MULTIPART_SIZE_LIMIT_IN_BYTES);
    parts += fileSize % S3_MULTIPART_SIZE_LIMIT_IN_BYTES > 0 ? 1 : 0;

    ByteBuffer checksumBuffer = ByteBuffer.allocate(parts * 16);

    SeekableByteChannel byteChannel = Files.newByteChannel(file);

    for (int part = 0; part < parts; part++) {

        int partSizeInBytes;

        if (part < parts - 1 || fileSize % S3_MULTIPART_SIZE_LIMIT_IN_BYTES == 0) {
            partSizeInBytes = S3_MULTIPART_SIZE_LIMIT_IN_BYTES;
        } else {//w  ww.  ja va2  s .  c  om
            partSizeInBytes = (int) (fileSize % S3_MULTIPART_SIZE_LIMIT_IN_BYTES);
        }

        ByteBuffer partBuffer = ByteBuffer.allocate(partSizeInBytes);

        boolean endOfFile;
        do {
            endOfFile = byteChannel.read(partBuffer) == -1;
        } while (!endOfFile && partBuffer.hasRemaining());

        checksumBuffer.put(DigestUtils.md5(partBuffer.array()));
    }

    if (parts > 1) {
        return DigestUtils.md5Hex(checksumBuffer.array()) + "-" + parts;
    } else {
        return Hex.encodeHexString(checksumBuffer.array());
    }
}

From source file:org.cryptomator.crypto.aes256.Aes256Cryptor.java

@Override
public Long decryptedContentLength(SeekableByteChannel encryptedFile) throws IOException {
    // skip 128bit IV + 256 bit MAC:
    encryptedFile.position(48);//w w w.  j a v  a  2  s . co  m

    // read encrypted value:
    final ByteBuffer encryptedFileSizeBuffer = ByteBuffer.allocate(AES_BLOCK_LENGTH);
    final int numFileSizeBytesRead = encryptedFile.read(encryptedFileSizeBuffer);

    // return "unknown" value, if EOF
    if (numFileSizeBytesRead != encryptedFileSizeBuffer.capacity()) {
        return null;
    }

    // decrypt size:
    try {
        final Cipher sizeCipher = aesEcbCipher(primaryMasterKey, Cipher.DECRYPT_MODE);
        final byte[] decryptedFileSize = sizeCipher.doFinal(encryptedFileSizeBuffer.array());
        final ByteBuffer fileSizeBuffer = ByteBuffer.wrap(decryptedFileSize);
        return fileSizeBuffer.getLong();
    } catch (IllegalBlockSizeException | BadPaddingException e) {
        throw new IllegalStateException(e);
    }
}

From source file:com.arpnetworking.metrics.common.tailer.StatefulTailer.java

private boolean readLines(final SeekableByteChannel reader) throws IOException {
    // Compute the hash if not already set
    if (!_hash.isPresent() && reader.size() >= REQUIRED_BYTES_FOR_HASH) {
        _hash = computeHash(reader, REQUIRED_BYTES_FOR_HASH);
    }/*from www .  j a v  a 2s .  c o m*/

    // Track current position in file and next read position
    // NOTE: The next read position is always the beginning of a line
    long position = reader.position();
    long nextReadPosition = position;

    // Reset buffers
    _buffer.clear();
    _lineBuffer.reset();

    // Process available data
    int bufferSize = reader.read(_buffer);
    boolean hasData = false;
    boolean hasCR = false;
    while (isRunning() && bufferSize != -1) {
        hasData = true;
        for (int i = 0; i < bufferSize; i++) {
            final byte ch = _buffer.get(i);
            switch (ch) {
            case '\n':
                hasCR = false;
                handleLine();
                nextReadPosition = position + i + 1;
                updateCheckpoint(nextReadPosition);
                break;
            case '\r':
                if (hasCR) {
                    _lineBuffer.write('\r');
                }
                hasCR = true;
                break;
            default:
                if (hasCR) {
                    hasCR = false;
                    handleLine();
                    nextReadPosition = position + i + 1;
                    updateCheckpoint(nextReadPosition);
                }
                _lineBuffer.write(ch);
            }
        }
        position = reader.position();
        _buffer.clear();
        bufferSize = reader.read(_buffer);
    }

    reader.position(nextReadPosition);
    return hasData;
}

From source file:com.arpnetworking.tsdcore.tailer.StatefulTailer.java

private Optional<String> computeHash(final SeekableByteChannel reader, final int hashSize) throws IOException {
    // Don't hash empty data sets
    if (hashSize <= 0) {
        return Optional.absent();
    }/*w  w  w. j  a  v a2s.  co m*/

    // Validate sufficient data to compute the hash
    final long oldPosition = reader.position();
    reader.position(0);
    if (reader.size() < hashSize) {
        reader.position(oldPosition);
        LOGGER.trace(String.format("Reader size insufficient to compute hash; hashSize=%s, hashSize=%d",
                Integer.valueOf(hashSize), Long.valueOf(reader.size())));
        return Optional.absent();
    }

    // Read the data to hash
    final ByteBuffer buffer = ByteBuffer.allocate(hashSize);
    int totalBytesRead = 0;
    while (totalBytesRead < hashSize) {
        final int bytesRead = reader.read(buffer);
        if (bytesRead < 0) {
            LOGGER.warn(String.format("Unexpected end of file reached; totalBytesRead=%d",
                    Long.valueOf(totalBytesRead)));
            return Optional.absent();
        }
        totalBytesRead += bytesRead;
    }

    // Compute the hash
    _md5.reset();
    final byte[] digest = _md5.digest(buffer.array());
    final String hash = Hex.encodeHexString(digest);
    LOGGER.trace(String.format("Computed hash; hash=%s, bytes=%s", hash, Hex.encodeHexString(buffer.array())));

    // Return the reader to its original state
    reader.position(oldPosition);
    return Optional.of(hash);
}

From source file:com.arpnetworking.metrics.common.tailer.StatefulTailer.java

private Optional<String> computeHash(final SeekableByteChannel reader, final int hashSize) throws IOException {
    // Don't hash empty data sets
    if (hashSize <= 0) {
        return Optional.empty();
    }//from w  ww .ja  va 2s.c o m

    // Validate sufficient data to compute the hash
    final long oldPosition = reader.position();
    reader.position(0);
    if (reader.size() < hashSize) {
        reader.position(oldPosition);
        LOGGER.trace().setMessage("Reader size insufficient to compute hash").addData("hashSize", hashSize)
                .addData("readerSize", reader.size()).log();
        return Optional.empty();
    }

    // Read the data to hash
    final ByteBuffer buffer = ByteBuffer.allocate(hashSize);
    int totalBytesRead = 0;
    while (totalBytesRead < hashSize) {
        final int bytesRead = reader.read(buffer);
        if (bytesRead < 0) {
            LOGGER.warn().setMessage("Unexpected end of file reached").addData("totalBytesRead", totalBytesRead)
                    .log();
            return Optional.empty();
        }
        totalBytesRead += bytesRead;
    }

    // Compute the hash
    _md5.reset();
    final byte[] digest = _md5.digest(buffer.array());
    final String hash = Hex.encodeHexString(digest);
    LOGGER.trace().setMessage("Computed hash").addData("hash", hash).log();

    // Return the reader to its original state
    reader.position(oldPosition);
    return Optional.of(hash);
}

From source file:io.neba.core.logviewer.Tail.java

@Override
public void run() {
    SeekableByteChannel channel = null;

    try {/*from   w  w w  . j  ava 2s  . com*/
        channel = newByteChannel(this.file.toPath(), READ);

        long availableInByte = this.file.length();
        long startingFromInByte = max(availableInByte - this.bytesToTail, 0);

        channel.position(startingFromInByte);

        long position = startingFromInByte;
        long totalBytesRead = 0L;

        // Read up to this amount of data from the file at once.
        ByteBuffer readBuffer = allocate(4096);
        while (!this.stopped) {

            // The file might be temporarily gone during rotation. Wait, then decide
            // whether the file is considered gone permanently or whether a rotation has occurred.
            if (!this.file.exists()) {
                sleep(AWAIT_FILE_ROTATION_MILLIS);
            }
            if (!this.file.exists()) {
                this.remoteEndpoint.sendString("file not found");
                return;
            }

            if (position > this.file.length()) {
                this.remoteEndpoint.sendString("file rotated");
                position = 0;
                closeQuietly(channel);
                channel = newByteChannel(this.file.toPath(), READ);
            }

            int read = channel.read(readBuffer);

            if (read == -1) {
                if (mode == TAIL) {
                    // EOF, we are done.
                    return;
                }
                // If we are in follow mode, reaching the end of the file might signal a file rotation. Sleep and re-try.
                sleep(TAIL_CHECK_INTERVAL_MILLIS);
                continue;
            }

            totalBytesRead += read;

            position = channel.position();
            readBuffer.flip();
            this.remoteEndpoint.sendBytes(readBuffer);
            readBuffer.clear();

            if (mode == TAIL && totalBytesRead >= this.bytesToTail) {
                return;
            }
        }
    } catch (IOException e) {
        this.logger.error("Unable to tail " + this.file.getAbsolutePath() + ".", e);
    } catch (InterruptedException e) {
        if (!this.stopped) {
            this.logger.error("Stopped tailing " + this.file.getAbsolutePath() + ", got interrupted.", e);
        }
    } finally {
        closeQuietly(channel);
    }
}

From source file:org.cryptomator.crypto.aes256.Aes256Cryptor.java

@Override
public boolean authenticateContent(SeekableByteChannel encryptedFile) throws IOException {
    // init mac:/*from www. j  av a  2  s  .com*/
    final Mac calculatedMac = this.hmacSha256(hMacMasterKey);

    // read stored mac:
    encryptedFile.position(16);
    final ByteBuffer storedMac = ByteBuffer.allocate(calculatedMac.getMacLength());
    final int numMacBytesRead = encryptedFile.read(storedMac);

    // check validity of header:
    if (numMacBytesRead != calculatedMac.getMacLength()) {
        throw new IOException("Failed to read file header.");
    }

    // read all encrypted data and calculate mac:
    encryptedFile.position(64);
    final InputStream in = new SeekableByteChannelInputStream(encryptedFile);
    final InputStream macIn = new MacInputStream(in, calculatedMac);
    IOUtils.copyLarge(macIn, new NullOutputStream());

    // compare (in constant time):
    return MessageDigest.isEqual(storedMac.array(), calculatedMac.doFinal());
}

From source file:org.cryptomator.crypto.aes256.Aes256Cryptor.java

@Override
public Long decryptedFile(SeekableByteChannel encryptedFile, OutputStream plaintextFile) throws IOException {
    // read iv://from  ww  w. j ava  2  s . c om
    encryptedFile.position(0);
    final ByteBuffer countingIv = ByteBuffer.allocate(AES_BLOCK_LENGTH);
    final int numIvBytesRead = encryptedFile.read(countingIv);

    // read file size:
    final Long fileSize = decryptedContentLength(encryptedFile);

    // check validity of header:
    if (numIvBytesRead != AES_BLOCK_LENGTH || fileSize == null) {
        throw new IOException("Failed to read file header.");
    }

    // go to begin of content:
    encryptedFile.position(64);

    // generate cipher:
    final Cipher cipher = this.aesCtrCipher(primaryMasterKey, countingIv.array(), Cipher.DECRYPT_MODE);

    // read content
    final InputStream in = new SeekableByteChannelInputStream(encryptedFile);
    final InputStream cipheredIn = new CipherInputStream(in, cipher);
    return IOUtils.copyLarge(cipheredIn, plaintextFile, 0, fileSize);
}