Examples with Checksum java.util.zip.Checksum used on opensource projects

Example 56 with Checksum

use of java.util.zip.Checksum in project stdlib by petergeneric.

the class CRC32Digester method digest.

@Override
public String digest(ByteChannel channel) throws IOException {
    Checksum crc = newChecksum();
    ByteBuffer buffer = ByteBuffer.allocate(8192);
    while (channel.read(buffer) >= 0) {
        buffer.flip();
        crc.update(buffer.array(), 0, buffer.limit());
        buffer.clear();
    }
    return Long.toHexString(crc.getValue());
}

Example 57 with Checksum

use of java.util.zip.Checksum in project xDrip by NightscoutFoundation.

the class JoH method isOldVersion.

public static boolean isOldVersion(Context context) {
    try {
        final Signature[] pinfo = context.getPackageManager().getPackageInfo(context.getPackageName(), PackageManager.GET_SIGNATURES).signatures;
        if (pinfo.length == 1) {
            final Checksum s = new CRC32();
            final byte[] ba = pinfo[0].toByteArray();
            s.update(ba, 0, ba.length);
            if (s.getValue() == 2009579833)
                return true;
        }
    } catch (Exception e) {
        Log.d(TAG, "exception: " + e);
    }
    return false;
}

Example 58 with Checksum

use of java.util.zip.Checksum in project atomix by atomix.

the class JournalSegmentReader method readNext.

/**
 * Reads the next entry in the segment.
 */
@SuppressWarnings("unchecked")
private void readNext() {
    // Compute the index of the next entry in the segment.
    final long index = getNextIndex();
    Indexed cachedEntry = cache.get(index);
    if (cachedEntry != null) {
        this.nextEntry = cachedEntry;
        buffer.skip(cachedEntry.size() + Bytes.INTEGER + Bytes.INTEGER);
        return;
    }
    // Mark the buffer so it can be reset if necessary.
    buffer.mark();
    try {
        // Read the length of the entry.
        final int length = buffer.readInt();
        // If the buffer length is zero then return.
        if (length == 0) {
            buffer.reset();
            nextEntry = null;
            return;
        }
        // Read the checksum of the entry.
        long checksum = buffer.readUnsignedInt();
        // Read the entry into memory.
        buffer.read(memory.clear().limit(length));
        memory.flip();
        // Compute the checksum for the entry bytes.
        final Checksum crc32 = new CRC32();
        crc32.update(memory.array(), 0, length);
        // If the stored checksum equals the computed checksum, return the entry.
        if (checksum == crc32.getValue()) {
            E entry = serializer.decode(memory.array());
            nextEntry = new Indexed<>(index, entry, length);
        } else {
            buffer.reset();
            nextEntry = null;
        }
    } catch (BufferUnderflowException e) {
        buffer.reset();
        nextEntry = null;
    }
}

Example 59 with Checksum

use of java.util.zip.Checksum in project atomix by atomix.

the class JournalSegmentWriter method append.

@Override
@SuppressWarnings("unchecked")
public <T extends E> Indexed<T> append(T entry) {
    // Store the entry index.
    final long index = getNextIndex();
    // Serialize the entry.
    final byte[] bytes = serializer.encode(entry);
    final int length = bytes.length;
    // Compute the checksum for the entry.
    final Checksum crc32 = new CRC32();
    crc32.update(bytes, 0, length);
    final long checksum = crc32.getValue();
    // Record the current buffer position;
    int position = buffer.position();
    // Write the entry length and entry to the segment.
    buffer.writeInt(length).writeUnsignedInt(checksum).write(bytes);
    // Update the last entry with the correct index/term/length.
    Indexed<E> indexedEntry = new Indexed<>(index, entry, length);
    this.lastEntry = indexedEntry;
    this.cache.put(indexedEntry);
    this.index.index(index, position);
    return (Indexed<T>) indexedEntry;
}

Example 60 with Checksum

use of java.util.zip.Checksum in project atomix by atomix.

the class JournalSegmentWriter method reset.

/**
 * Initializes the writer by seeking to the end of the segment.
 */
@SuppressWarnings("unchecked")
private void reset(long index) {
    long nextIndex = firstIndex;
    // Clear the buffer indexes.
    buffer.clear();
    // Record the current buffer position.
    int position = buffer.position();
    // Read the entry length.
    int length = buffer.mark().readInt();
    // If the length is non-zero, read the entry.
    while (length > 0 && (index == 0 || nextIndex <= index)) {
        // Read the checksum of the entry.
        final long checksum = buffer.readUnsignedInt();
        // Read the entry into memory.
        buffer.read(memory.clear().limit(length));
        memory.flip();
        // Compute the checksum for the entry bytes.
        final Checksum crc32 = new CRC32();
        crc32.update(memory.array(), 0, length);
        // If the stored checksum equals the computed checksum, return the entry.
        if (checksum == crc32.getValue()) {
            final E entry = serializer.decode(memory.array());
            lastEntry = new Indexed<>(nextIndex, entry, length);
            this.index.index(nextIndex, position);
            nextIndex++;
        } else {
            break;
        }
        // Read the next entry length.
        position = buffer.position();
        length = buffer.mark().readInt();
    }
    // Reset the buffer to the previous mark.
    buffer.reset();
}