Examples of Adler32

com.sleepycat.je.utilint.Adler32
Adler32 checksum implementation. This class is used rather than the native java.util.zip.Adler32 class because we have seen a JIT problem when calling the Adler32 class using the Server JVM on Linux and Solaris. Specifically, we suspect this may be Bug Parade number 4965907. See SR [#9376]. We also believe that this bug is fixed in Java 5 and therefore only use this class conditionally if we find that we're in a 1.4 JVM. [#13354]. The Adler32 checksum is discussed in RFC1950. The sample implementation from this RFC is shown below:
```
 #define BASE 65521  largest prime smaller than 65536 unsigned long update_adler32(unsigned long adler, unsigned char *buf, int len) { unsigned long s1 = adler & 0xffff; unsigned long s2 = (adler >> 16) & 0xffff; int n; for (n = 0; n < len; n++) { s1 = (s1 + buf[n]) % BASE; s2 = (s2 + s1)     % BASE; } return (s2 << 16) + s1; } unsigned long adler32(unsigned char *buf, int len) { return update_adler32(1L, buf, len); } 
```
The NMAX optimization is so that we don't have to do modulo calculations on every iteration. NMAX is the max number of additions to make before you have to perform the modulo calculation.
java.util.zip.Adler32
A class that can be used to compute the Adler-32 checksum of a data stream. An Adler-32 checksum is almost as reliable as a CRC-32 but can be computed much faster. @see Checksum @version 1.29, 11/17/05 @author David Connelly

Examples of java.util.zip.Adler32

        /**
         * create a checksum algorithm
         * @return the checksum algorithm
         */
        protected Checksum makeChecksumAlgorithm(){
            return new Adler32();
        }

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Examples of java.util.zip.Adler32

                // Using Adler-32 instead of CRC-32 because it's much faster and
                // it's
                // weakness for short messages with few hundred bytes is not a
                // factor in this case since we know
                // our write batches are going to much larger.
                Checksum checksum = new Adler32();
                for (PageWrite w : batch) {
                    try {
                        checksum.update(w.diskBound, 0, pageSize);
                    } catch (Throwable t) {
                        throw IOExceptionSupport.create(
                                "Cannot create recovery file. Reason: " + t, t);
                    }
                }


                // Can we shrink the recovery buffer??
                if (recoveryPageCount > recoveryFileMaxPageCount) {
                    int t = Math.max(recoveryFileMinPageCount, batch.size());
                    recoveryFile.setLength(recoveryFileSizeForPages(t));
                }


                // Record the page writes in the recovery buffer.
                recoveryFile.seek(0);
                // Store the next tx id...
                recoveryFile.writeLong(nextTxid.get());
                // Store the checksum for thw write batch so that on recovery we
                // know if we have a consistent
                // write batch on disk.
                recoveryFile.writeLong(checksum.getValue());
                // Write the # of pages that will follow
                recoveryFile.writeInt(batch.size());


                // Write the pages.
                recoveryFile.seek(RECOVERY_FILE_HEADER_SIZE);

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Examples of java.util.zip.Adler32

        long nextTxId = recoveryFile.readLong();
        long expectedChecksum = recoveryFile.readLong();
        int pageCounter = recoveryFile.readInt();
        
        recoveryFile.seek(RECOVERY_FILE_HEADER_SIZE);
        Checksum checksum = new Adler32();
        LinkedHashMap<Long, byte[]> batch = new LinkedHashMap<Long, byte[]>();
        try {
            for (int i = 0; i < pageCounter; i++) {
                long offset = recoveryFile.readLong();
                byte []data = new byte[pageSize];
                if( recoveryFile.read(data, 0, pageSize) != pageSize ) {
                    // Invalid recovery record, Could not fully read the data". Probably due to a partial write to the recovery buffer
                    return nextTxId;
                }
                checksum.update(data, 0, pageSize);
                batch.put(offset, data);
            }
        } catch (Exception e) {
            // If an error occurred it was cause the redo buffer was not full written out correctly.. so don't redo it. 
            // as the pages should still be consistent.
            LOG.debug("Redo buffer was not fully intact: ", e);
            return nextTxId;
        }
        
        recoveryPageCount = pageCounter;
        
        // If the checksum is not valid then the recovery buffer was partially written to disk.
        if( checksum.getValue() != expectedChecksum ) {
            return nextTxId;
        }
        
        // Re-apply all the writes in the recovery buffer.
        for (Map.Entry<Long, byte[]> e : batch.entrySet()) {

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Examples of java.util.zip.Adler32

        return ((double) nanos) * NANOS_TO_MILLIS;
    }


    public static long toChecksum(Resource resource)
    {
        Adler32 checksum = new Adler32();


        byte[] buffer = new byte[1024];


        InputStream is = null;


        try
        {
            is = resource.openStream();


            while (true)
            {
                int length = is.read(buffer);


                if (length < 0)
                {
                    break;
                }


                checksum.update(buffer, 0, length);
            }


            is.close();


            // Reduces it down to just 32 bits which we express in hex.'
            return checksum.getValue();
        } catch (IOException ex)
        {
            throw new RuntimeException(ex);
        }
    }

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Examples of java.util.zip.Adler32

        output.write(signature);
        output.close();
    }


    private void updateChecksum(@Nonnull DexDataStore dataStore) throws IOException {
        Adler32 a32 = new Adler32();


        byte[] buffer = new byte[4 * 1024];
        InputStream input = dataStore.readAt(HeaderItem.CHECKSUM_DATA_START_OFFSET);
        int bytesRead = input.read(buffer);
        while (bytesRead >= 0) {
            a32.update(buffer, 0, bytesRead);
            bytesRead = input.read(buffer);
        }


        // write checksum, utilizing logic in DexWriter to write the integer value properly
        OutputStream output = dataStore.outputAt(HeaderItem.CHECKSUM_OFFSET);
        DexDataWriter.writeInt(output, (int)a32.getValue());
        output.close();
    }

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Examples of java.util.zip.Adler32

                buffer.array(), buffer.writerIndex(), buffer.writableBytes() - 4);
        message.writeTo(output);
        output.checkNoSpaceLeft();


        buffer.writerIndex(writerIndex + size);
        Adler32 checksum = new Adler32();
        checksum.update(buffer.array(), buffer.arrayOffset(), buffer.readableBytes());
        buffer.writeInt((int) checksum.getValue());
        return buffer;
    }

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Examples of java.util.zip.Adler32

        if (obj instanceof ChannelBuffer) {
            ChannelBuffer buffer = (ChannelBuffer) obj;
            if (buffer.readableBytes() > 8) {
                String version = buffer.toString(buffer.readerIndex(), 4, Charset.defaultCharset());
                if (version.equals("RPC0")) {
                    Adler32 adler32 = new Adler32();
                    adler32.update(buffer.array(),
                            buffer.arrayOffset() + buffer.readerIndex(),
                            buffer.readableBytes() - 4);
                    buffer.markReaderIndex();
                    buffer.readerIndex(buffer.writerIndex() - 4);
                    int checksum = buffer.readInt();
                    if (checksum == (int)adler32.getValue()) {
                        buffer.resetReaderIndex();
                        RpcMessage message = RpcMessage.newBuilder().mergeFrom(
                                buffer.array(),
                                buffer.arrayOffset() + buffer.readerIndex() + 4,
                                buffer.readableBytes() - 8).build();

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Examples of java.util.zip.Adler32

        buffer.writeInt(name.length() + 1);
        buffer.writeBytes(name.getBytes());
        buffer.writeZero(1);
        buffer.writeBytes(message.toByteArray());


        Adler32 checksum = new Adler32();
        checksum.update(buffer.array(), buffer.arrayOffset(), buffer.readableBytes());
        buffer.writeInt((int) checksum.getValue());


        return buffer;
    }

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Examples of java.util.zip.Adler32

        }
        return obj;
    }


    private boolean checksum(ChannelBuffer buffer) {
        Adler32 adler32 = new Adler32();
        adler32.update(buffer.array(),
                buffer.arrayOffset() + buffer.readerIndex(),
                buffer.readableBytes() - 4);
        buffer.markReaderIndex();
        buffer.readerIndex(buffer.writerIndex() - 4);
        int checksum = buffer.readInt();
        buffer.resetReaderIndex();
        return checksum == (int) adler32.getValue();
    }

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Examples of java.util.zip.Adler32

public class ChecksumCalculator extends VisitorAdapter {


  private Adler32 checksum;


  public ChecksumCalculator() {
    checksum = new Adler32();
  }

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