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

    return album;
  }




  public long calculateChecksum() {
    Adler32 adler = new Adler32();
    for (Track track : tracks) {
      adler.update(track.getUUID());
      adler.update(0x01);
    }
    return adler.getValue();
  }

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Examples of java.util.zip.Adler32

    /** Faster than CRC32, nearly as good.
     * @see Adler32
     */
    public static long adler32(byte[] bytes)
    {
        return crc(new Adler32(), bytes) ;
    }

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Examples of java.util.zip.Adler32

        int blkId = (block==null) ? NoId : block.getId().intValue() ;
        header.putInt(blkId) ;
        header.flip() ;
        channel.write(header) ;
        
        Adler32 adler = new Adler32() ;
        adler.update(header.array()) ;


        if ( len > 0 )
        {
            // Make buffer include it's full length.
            // [TxDEV:TODO] This is the full buffer, junk and all.
            // This makes the system able to check block sizes (BlockAccess checking).
            
            int bufferLimit = buffer.limit() ;
            int bufferPosition = buffer.position() ;
            buffer.position(0) ;
            buffer.limit(bufferCapacity) ;
            // Clear top.
            for ( int i = len ; i < bufferCapacity ; i++ )
                buffer.put(i, (byte)0) ;
            
            // Write all bytes
            channel.write(buffer) ;
            if (buffer.hasArray())
            {
                adler.update(buffer.array()) ;
            }
            else
            {
                byte[] data = new byte[bufferCapacity] ;
                buffer.position(0) ;
                buffer.limit(bufferCapacity) ;
                buffer.get(data) ;
                adler.update(data) ;
            }
            
            buffer.position(bufferPosition) ;
            buffer.limit(bufferLimit) ;
        }


        // checksum
        crcTrailer.clear() ;
        Bytes.setInt((int)adler.getValue(), crcTrailer.array()) ;
        channel.write(crcTrailer) ;


        position += Overhead + len + SizeofCRC ; // header + payload + checksum
        return posn ;
    }

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Examples of java.util.zip.Adler32

        int typeId  = header.getInt() ; 
        int len     = header.getInt() ;
        int ref     = header.getInt() ;
        int blockId = header.getInt() ;
        
        Adler32 adler = new Adler32() ;
        adler.update(header.array()) ;


        ByteBuffer bb = ByteBuffer.allocate(len) ;
        lenRead = channel.read(bb) ;
        if ( lenRead != len)
            throw new TDBTransactionException("Failed to read the journal entry: wanted "+len+" bytes, got "+lenRead) ;
        adler.update(bb.array()) ;
        bb.rewind() ;
        // checksum
        crcTrailer.clear() ;
        lenRead = channel.read(crcTrailer) ;
        if ( lenRead != SizeofCRC )
            throw new TDBTransactionException("Failed to read block checksum (got "+lenRead+" bytes, not "+SizeofCRC+").") ;
        int checksum = Bytes.getInt(crcTrailer.array()) ;
        if ( checksum != (int)adler.getValue() )
          throw new TDBTransactionException("Checksum error reading from the Journal.") ;


        JournalEntryType type = JournalEntryType.type(typeId) ;
        FileRef fileRef = FileRef.get(ref) ;

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Examples of java.util.zip.Adler32

            }


            byte data[] = new byte[size];
            reader.readFully(offset+BATCH_CONTROL_RECORD_SIZE, data);


            Checksum checksum = new Adler32();
            checksum.update(data, 0, data.length);


            if( expectedChecksum!=checksum.getValue() ) {
                return -1;
            }


        }
        return size;

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Examples of java.util.zip.Adler32

            // release the folks that were waiting for those writes to hit disk.
            checkpointLatch = this.checkpointLatch;
            this.checkpointLatch = null;
        }


        Checksum checksum = new Adler32();
        if (enableRecoveryFile) {
            recoveryFile.seek(RECOVERY_FILE_HEADER_SIZE);
        }
        for (PageWrite w : batch) {
            if (enableRecoveryFile) {
                try {
                    checksum.update(w.getDiskBound(), 0, pageSize);
                } catch (Throwable t) {
                    throw IOExceptionSupport.create("Cannot create recovery file. Reason: " + t, t);
                }
                recoveryFile.writeLong(w.page.getPageId());
                recoveryFile.write(w.getDiskBound(), 0, pageSize);
            }


            writeFile.seek(toOffset(w.page.getPageId()));
            writeFile.write(w.getDiskBound(), 0, pageSize);
            w.done();
        }


        try {
            if (enableRecoveryFile) {
                // 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());
            }


            if (enableDiskSyncs) {

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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

                // Now we can fill in the batch control record properly.
                buff.reset();
                buff.skip(5+Journal.BATCH_CONTROL_RECORD_MAGIC.length);
                buff.writeInt(sequence.getLength()-Journal.BATCH_CONTROL_RECORD_SIZE);
                if( journal.isChecksum() ) {
                    Checksum checksum = new Adler32();
                    checksum.update(sequence.getData(), sequence.getOffset()+Journal.BATCH_CONTROL_RECORD_SIZE, sequence.getLength()-Journal.BATCH_CONTROL_RECORD_SIZE);
                    buff.writeLong(checksum.getValue());
                }


                // Now do the 1 big write.
                file.seek(wb.offset);
                if (maxStat > 0) {

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Examples of java.util.zip.Adler32

                // Now we can fill in the batch control record properly. 
                buff.reset();
                buff.skip(5+Journal.BATCH_CONTROL_RECORD_MAGIC.length);
                buff.writeInt(sequence.getLength()-Journal.BATCH_CONTROL_RECORD_SIZE);
                if( journal.isChecksum() ) {
                  Checksum checksum = new Adler32();
                  checksum.update(sequence.getData(), sequence.getOffset()+Journal.BATCH_CONTROL_RECORD_SIZE, sequence.getLength()-Journal.BATCH_CONTROL_RECORD_SIZE);
                  buff.writeLong(checksum.getValue());
                }


                // Now do the 1 big write.
                file.seek(wb.offset);
                if (maxStat > 0) {

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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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