Java Code Examples for java.nio.MappedByteBuffer#position()

private void save()
{
  Assert.assertTrue(max_data_size >= getMinAlloc());
  Assert.assertNotEquals(0, data_loc);
  Assert.assertNotNull(key);
  Assert.assertNotNull(value);


  int file = (int) (data_loc / SEGMENT_FILE_SIZE);
  MappedByteBuffer mbb = getBufferMap(file);
  int offset = (int) (data_loc % SEGMENT_FILE_SIZE);
  synchronized(mbb)
  {
    mbb.position(offset);
    mbb.putInt(max_data_size);
    mbb.putShort((short)key.size());
    mbb.put(key.toByteArray());
    mbb.putInt(value.size());
    mbb.put(value.toByteArray());
  }

}
 

private void damageCommitlog(long offset) throws Exception {
    MessageStoreConfig messageStoreConfig = new MessageStoreConfig();
    File file = new File(messageStoreConfig.getStorePathCommitLog() + File.separator + "00000000000000000000");

    FileChannel fileChannel = new RandomAccessFile(file, "rw").getChannel();
    MappedByteBuffer mappedByteBuffer = fileChannel.map(FileChannel.MapMode.READ_WRITE, 0, 1024 * 1024 * 10);

    int bodyLen = mappedByteBuffer.getInt((int) offset + 84);
    int topicLenIndex = (int) offset + 84 + bodyLen + 4;
    mappedByteBuffer.position(topicLenIndex);
    mappedByteBuffer.putInt(0);
    mappedByteBuffer.putInt(0);
    mappedByteBuffer.putInt(0);
    mappedByteBuffer.putInt(0);

    mappedByteBuffer.force();
    fileChannel.force(true);
    fileChannel.close();
}
 

private synchronized void grow() {
    try {
        long start = this.units.size() * Unit.SIZE;
        MappedByteBuffer mmf = this.ch.map(MapMode.READ_WRITE, start, Unit.SIZE * 100);
        this.mmfs.add(mmf);
        mmf.order(ByteOrder.nativeOrder());
        for (int i=0; i<100; i++) {
            Unit ii = new Unit();
            mmf.position(i * Unit.SIZE);
            mmf.limit(mmf.position() + Unit.SIZE);
            ii.buf = mmf.slice();
            ii.addr = UberUtil.getAddress(ii.buf);
            this.units.add(ii);
        }
    }
    catch (Exception ignored) {
        // if it fails then nothing is logged
    }
}
 

private static void resetSymbolAddressesInSymbolTable(
    MappedByteBuffer machoBuffer, MachoSymTabCommand symTabCommand) {
  machoBuffer.position(symTabCommand.getSymbolTableOffset());

  for (int i = 0; i < symTabCommand.getNumberOfSymbolTableEntries(); ++i) {
    // struct nlist_64 {
    //     union {
    //         uint32_t  n_strx;  // index into the string table
    //     } n_un;
    //     uint8_t n_type;        // type flag, see below
    //     uint8_t n_sect;        // section number or NO_SECT
    //     uint16_t n_desc;       // see <mach-o/stab.h>
    //     uint64_t n_value;      // value of this symbol (or stab offset)
    // };
    ObjectFileScrubbers.getLittleEndianInt(machoBuffer); // n_strx
    machoBuffer.get(); // n_type
    machoBuffer.get(); // n_sect
    ObjectFileScrubbers.getLittleEndianShort(machoBuffer); // n_desc
    ObjectFileScrubbers.putLittleEndianLong(machoBuffer, 0x0); // n_value
  }
}
 

public void putBytes(long position, byte[] buff)
{
  long t1 = System.nanoTime();
  //Assert.assertTrue(position >= 0);
  //Assert.assertTrue(position + buff.length <= total_size);

  int to_write=buff.length;

  int start_file = (int) (position / MAP_SIZE);
  int start_offset = (int) (position % MAP_SIZE);

  MappedByteBuffer map = map_list.get(start_file);

  map.position(start_offset);
  int len = Math.min(to_write, (int) (MAP_SIZE - start_offset));

  map.put(buff, 0, len);
  if (len < to_write)
  {
    map = map_list.get(start_file + 1);
    map.position(0);
    map.put(buff, len, to_write - len);
  }
  TimeRecord.record(t1, "long_map_put_bytes");
}
 

public synchronized void getBytes(long position, byte[] buff)
{
  long t1 = System.nanoTime();

  //Assert.assertTrue(position >= 0);
  //Assert.assertTrue(position + buff.length <= total_size);

  int to_read=buff.length;

  int start_file = (int) (position / MAP_SIZE);
  int start_offset = (int) (position % MAP_SIZE);

  MappedByteBuffer map = map_list.get(start_file);

  map.position(start_offset);
  int len = Math.min(to_read, (int) (MAP_SIZE - start_offset));

  map.get(buff, 0, len);
  if (len < to_read)
  {
    map = map_list.get(start_file + 1);
    map.position(0);
    map.get(buff, len, to_read - len);
  }
  TimeRecord.record(t1, "long_map_get_bytes");
}
 

@Override
public StepExecutionResult execute(ExecutionContext context) throws IOException {
  try (FileChannel channel =
      FileChannel.open(
          getFilesystem().resolve(getPath()),
          StandardOpenOption.READ,
          StandardOpenOption.WRITE)) {
    MappedByteBuffer buffer = channel.map(READ_WRITE, 0, channel.size());
    Elf elf = new Elf(buffer);
    Preconditions.checkState(
        elf.header.e_phoff == (int) elf.header.e_phoff,
        "program headers are expected to be within 4GB of beginning of file");
    buffer.position((int) elf.header.e_phoff);
    for (int index = 0; index < elf.header.e_phnum * elf.header.e_phentsize; index++) {
      buffer.put((byte) 0);
    }
  }
  return StepExecutionResults.SUCCESS;
}
 

public ByteBuffer getBuffer(DumpIndex idx) throws IOException {
    if (cache.containsKey(idx)) {
        MappedByteBuffer b = cache.get(idx);
        b.position(0);
        return b.duplicate().order(b.order());
    }
    FileChannel channel = dump.getChannel();
    MappedByteBuffer res = channel.map(FileChannel.MapMode.READ_ONLY, idx.filePos, idx.size);
    res.order(ByteOrder.LITTLE_ENDIAN);
    cache.put(idx, res);
    return res.duplicate().order(res.order());
}
 

private void open(boolean write) throws IOException {
    if (this.raf != null) {
        return;
    }
    
    // rename the existing file so we dont accidently lose previous crash scene
    if (write && file.exists()) {
        String filename = file.getName();
        filename = System.currentTimeMillis() + "-" + filename;
        File backup = new File(file.getParentFile(), filename);
        file.renameTo(backup);
    }
    
    // open it
    this.raf = new RandomAccessFile(file, write ? "rw" : "r");
    this.ch = this.raf.getChannel();
    
    // map units if this is read only
    if (!write) {
        int nbuffers = (int)(this.file.length() / Unit.SIZE); 
        MappedByteBuffer mmf = raf.getChannel().map(MapMode.READ_ONLY, 0, Unit.SIZE * nbuffers);
        this.mmfs.add(mmf);
        mmf.order(ByteOrder.nativeOrder());
        for (int i=0; i<nbuffers; i++) {
            Unit ii = new Unit();
            mmf.position(i * Unit.SIZE);
            mmf.limit(mmf.position() + Unit.SIZE);
            ii.buf = mmf.slice();
            ii.addr = UberUtil.getAddress(ii.buf);
            this.units.add(ii);
        }
        this.ch.close();
        this.raf.close();
    }
}
 

private byte[] getBytes(
    long offset, int nameLength, int cenExtLength, long size, boolean deflate) {
  if (size > Integer.MAX_VALUE) {
    throw new IllegalArgumentException("unsupported zip entry size: " + size);
  }
  try {
    MappedByteBuffer fc =
        chan.map(
            MapMode.READ_ONLY,
            offset,
            Math.min(
                LOCHDR + nameLength + cenExtLength + size + EXTRA_FIELD_SLACK,
                chan.size() - offset));
    fc.order(ByteOrder.LITTLE_ENDIAN);
    checkSignature(path, fc, /* index= */ 0, 3, 4, "LOCSIG");
    int locExtLength = fc.getChar(LOCEXT);
    if (locExtLength > cenExtLength + EXTRA_FIELD_SLACK) {
      // If the local header's extra fields don't match the central directory and we didn't
      // leave enough slac, re-map the data section with the correct extra field length.
      fc = chan.map(MapMode.READ_ONLY, offset + LOCHDR + nameLength + locExtLength, size);
      fc.order(ByteOrder.LITTLE_ENDIAN);
    } else {
      // Otherwise seek past the local header, name, and extra fields to the data.
      fc.position(LOCHDR + nameLength + locExtLength);
      fc.limit((int) (LOCHDR + nameLength + locExtLength + size));
    }
    byte[] bytes = new byte[(int) size];
    fc.get(bytes);
    if (deflate) {
      bytes =
          ByteStreams.toByteArray(
              new InflaterInputStream(
                  new ByteArrayInputStream(bytes), new Inflater(/*nowrap=*/ true)));
    }
    return bytes;
  } catch (IOException e) {
    throw new IOError(e);
  }
}
 

private void flush(T entry) throws IOException {
    Queue<T> inMemQueue = getInMemoryQueue();
    int resultSize = sizeOf(entry);
    maxResultSize = Math.max(maxResultSize, resultSize);
    totalResultSize = hasMaxQueueSize ? maxResultSize * inMemQueue.size() : (totalResultSize + resultSize);
    if (totalResultSize >= thresholdBytes) {
        this.file = File.createTempFile(UUID.randomUUID().toString(), null);
        RandomAccessFile af = new RandomAccessFile(file, "rw");
        FileChannel fc = af.getChannel();
        int writeIndex = 0;
        mappingSize = Math.min(Math.max(maxResultSize, DEFAULT_MAPPING_SIZE), totalResultSize);
        MappedByteBuffer writeBuffer = fc.map(MapMode.READ_WRITE, writeIndex, mappingSize);

        int resSize = inMemQueue.size();
        for (int i = 0; i < resSize; i++) {                
            T e = inMemQueue.poll();
            writeToBuffer(writeBuffer, e);
            // buffer close to exhausted, re-map.
            if (mappingSize - writeBuffer.position() < maxResultSize) {
                writeIndex += writeBuffer.position();
                writeBuffer = fc.map(MapMode.READ_WRITE, writeIndex, mappingSize);
            }
        }
        writeBuffer.putInt(EOF); // end
        fc.force(true);
        fc.close();
        af.close();
        flushedCount = resSize;
        inMemQueue.clear();
        flushBuffer = true;
    }
}
 

protected void writeLong(long position, long value)
{
  int file = (int) (position / SEGMENT_FILE_SIZE);
  int offset_in_file = (int) (position % SEGMENT_FILE_SIZE);
  MappedByteBuffer mbb = getBufferMap(file);
  synchronized(mbb)
  {
    mbb.position(offset_in_file);
    mbb.putLong(value);
  }
}
 

protected Map<String, Integer> loadTroughMap()
{
  TreeMap<String,Integer> map = new TreeMap<>();

  MappedByteBuffer mbb = getBufferMap(0);
  synchronized(mbb)
  {
    for(int i=0; i<MAX_TROUGHS; i++)
    {
      mbb.position( (int)(LOCATION_TROUGH_TABLE_START + (8 + MAX_TROUGH_NAME_LEN) * i));
      long ptr = mbb.getLong();
      byte[] name = new byte[MAX_TROUGH_NAME_LEN];
      mbb.get(name);
      int len =0;
      for(int j=0; (j<MAX_TROUGH_NAME_LEN) && (name[j] != 0); j++)
      {
        len++;
      }
      if (len > 0)
      {
        String name_str = new String(name, 0, len);
        map.put(name_str, i);
      }
      else
      {
        map.put("__FREE", i);
      }
    }
  }
  return map;
}
 

protected void writeInt(long position, int value)
{
  int file = (int) (position / SEGMENT_FILE_SIZE);
  int offset_in_file = (int) (position % SEGMENT_FILE_SIZE);
  MappedByteBuffer mbb = getBufferMap(file);
  synchronized(mbb)
  {
    mbb.position(offset_in_file);
    mbb.putInt(value);
  }
}
 

@Override
public StepExecutionResult execute(ExecutionContext context) throws IOException {
  try (FileChannel channel =
      FileChannel.open(
          getFilesystem().resolve(getPath()),
          StandardOpenOption.READ,
          StandardOpenOption.WRITE)) {
    MappedByteBuffer buffer = channel.map(READ_WRITE, 0, channel.size());
    Elf elf = new Elf(buffer);

    ImmutableList<SectionUsingDynamicStrings> processors = getSectionProcesors(elf);

    // Load the dynamic string table.
    Elf.ElfSectionLookupResult dynStrSection = elf.getMandatorySectionByName(getPath(), DYNSTR);
    byte[] dynStr = new byte[dynStrSection.getSection().body.remaining()];
    dynStrSection.getSection().body.get(dynStr);

    // Collect all the string references from the section processors.
    ImmutableList<Long> stringIndices =
        RichStream.from(processors)
            .flatMap(p -> p.getStringReferences().stream())
            .toImmutableList();

    // Write the new dynamic string table out to a byte array and get the new string indices
    // corresponding to the order of the collected string indices.
    ByteArrayOutputStream newDynStrStream = new ByteArrayOutputStream();
    ImmutableList<Integer> newStringIndices =
        ElfStringTable.writeStringTableFromStringTable(
            dynStr,
            RichStream.from(stringIndices).map(i -> (int) (long) i).toImmutableList(),
            newDynStrStream);
    Preconditions.checkState(stringIndices.size() == newStringIndices.size());
    byte[] newDynStr = newDynStrStream.toByteArray();
    Preconditions.checkState(dynStrSection.getSection().header.sh_size >= newDynStr.length);

    // Generate a map from old to new string indices which sections can use to update themselves.
    Map<Long, Long> newStringIndexMapBuilder = new HashMap<>();
    for (int i = 0; i < stringIndices.size(); i++) {
      newStringIndexMapBuilder.put(stringIndices.get(i), (long) newStringIndices.get(i));
    }
    ImmutableMap<Long, Long> newStringIndexMap = ImmutableMap.copyOf(newStringIndexMapBuilder);

    // Call back into the processors to update themselves with the new string indices.
    processors.forEach(p -> p.processNewStringReferences(newDynStr.length, newStringIndexMap));

    // Rewrite the dynamic string section.
    dynStrSection.getSection().body.rewind();
    dynStrSection.getSection().body.put(newDynStr);

    // Fixup the version section header with the new size and write it out.
    buffer.position(
        (int) (elf.header.e_shoff + dynStrSection.getIndex() * elf.header.e_shentsize));
    dynStrSection
        .getSection()
        .header
        .withSize(dynStrSection.getSection().body.position())
        .write(elf.header.ei_class, buffer);
  }
  return StepExecutionResults.SUCCESS;
}
 

/**
 * Compute lenght of this sequence - quite expensive operation, indeed.
 */
@Override
public int length() {
    if (length != -1) {
        return length;
    }
    long start = System.currentTimeMillis();
    int charactersRead = 0;
    long bytesRead = 0;
    MappedByteBuffer mappedByteBuffer = null;
    CharBuffer charBuffer = CharBuffer.allocate(SIZE_LIMIT);
    CharsetDecoder decoder = prepareDecoder(charset);
    decoder.onUnmappableCharacter(CodingErrorAction.IGNORE);

    try {
        while (bytesRead < fileSize) {
            mappedByteBuffer = fileChannel.map(
                    FileChannel.MapMode.READ_ONLY, bytesRead,
                    Math.min(SIZE_LIMIT, fileSize - bytesRead));
            CoderResult result;
            do {
                charBuffer.clear();
                result = decoder.decode(
                        mappedByteBuffer, charBuffer,
                        bytesRead + SIZE_LIMIT >= fileSize);
                if (result.isUnmappable() || result.isMalformed()
                        || result.isError()) {
                    throw new IOException("Error decoding file: "
                            + result.toString() + " ");
                }
                if (bytesRead + SIZE_LIMIT >= fileSize) {
                    LOG.info("Coding end");
                }
                charactersRead += charBuffer.position();
            } while (result.isOverflow());

            int readNow = mappedByteBuffer.position();
            bytesRead += readNow;
            unmap(mappedByteBuffer);
        }
        charBuffer.clear();
        boolean repeat;
        do {
            repeat = decoder.flush(charBuffer).isOverflow();
            charactersRead += charBuffer.position();
            charBuffer.clear();
        } while (repeat);
    } catch (IOException ex) {
        if (mappedByteBuffer != null) {
            unmap(mappedByteBuffer);
        }
        Exceptions.printStackTrace(ex);
    }
    length = charactersRead;
    LOG.log(Level.INFO, "Length computed in {0} ms.", //NOI18N
            System.currentTimeMillis() - start);
    return length;
}
 

public static void main(String[] args) throws Exception {
    File file = new File(
            "c:\\Program Files (x86)\\Bethesda.net Launcher\\games\\Fallout76\\Data\\SeventySix.esm");

    Set<String> editorIds = new HashSet<>();
    /*
     * char[4] = 'EDID'
     * uint16 = length
     * uint8[length] = characters
     */
    int i = 1;
    try (RandomAccessFile raf = new RandomAccessFile(file, "r")) {

        MappedByteBuffer mbb = raf.getChannel().map(MapMode.READ_ONLY, 0, raf.length());
        
        while (mbb.remaining() > 0) {
            if (mbb.get() == 'E') {
                if (mbb.get() == 'D') {
                    if (mbb.get() == 'I') {
                        if (mbb.get() == 'D') {
                            int len = Short.reverseBytes(mbb.getShort()) & 0xFFFF;
                            byte[] data = new byte[len];
                            mbb.get(data);
                            editorIds.add(new String(data, StandardCharsets.ISO_8859_1));
                            if (i % 100 == 0) {
                                System.out.println("Records so far: " + i);
                            }
                            i++;
                        } else {
                            mbb.position(mbb.position() - 3);
                        }
                    } else {
                        mbb.position(mbb.position() - 2);
                    }
                } else {
                    mbb.position(mbb.position() - 1);
                }
            }
        }
    }
    
    SwingUtilities.invokeLater(() -> {
        JFrame frame = new JFrame();
        frame.setTitle("Find Editor IDs");
        frame.setDefaultCloseOperation(JFrame.DISPOSE_ON_CLOSE);
        frame.setSize(1000, 800);
        
        frame.setLocationRelativeTo(null);
        
        JTextField search = new JTextField();
        frame.add(search, BorderLayout.PAGE_START);
        Font f = new Font(Font.SANS_SERIF, Font.PLAIN, 22);
        search.setFont(f);
        
        JTextPane text = new JTextPane();
        JScrollPane scroll = new JScrollPane(text);
        frame.add(scroll, BorderLayout.CENTER);
        f = new Font(Font.MONOSPACED, Font.PLAIN, 22);
        text.setFont(f);
        
        frame.setVisible(true);
        
        search.addActionListener(e -> {
            text.setText("");
            
            String find = search.getText().trim().toLowerCase();
            String[] ands = find.split("\\s+");
            
            List<String> found = new ArrayList<>();
            if (find.length() > 0) {
                for (String s : editorIds) {
                    boolean has = true;
                    for (String a : ands) {
                        if (!s.toLowerCase().contains(a)) {
                            has = false;
                            break;
                        }
                    }
                    if (has) {
                        found.add(s);
                    }
                }
                
                if (found.size() == 0) {
                    text.setText("<not found>");
                } else {
                    Collections.sort(found, String.CASE_INSENSITIVE_ORDER);
                    text.setText(String.join("\r\n", found));
                    text.setCaretPosition(0);
                }
            }
        });
    });
}
 

public ZipIterable(Path path) throws IOException {
  this.path = path;
  this.chan = FileChannel.open(path, StandardOpenOption.READ);
  // Locate the EOCD
  long size = chan.size();
  if (size < ENDHDR) {
    throw new ZipException("invalid zip archive");
  }
  long eocdOffset = size - ENDHDR;
  MappedByteBuffer eocd = chan.map(MapMode.READ_ONLY, eocdOffset, ENDHDR);
  eocd.order(ByteOrder.LITTLE_ENDIAN);
  int index = 0;
  int commentSize = 0;
  if (!isSignature(eocd, 0, 5, 6)) {
    // The archive may contain a zip file comment; keep looking for the EOCD.
    long start = Math.max(0, size - ENDHDR - 0xFFFF);
    eocd = chan.map(MapMode.READ_ONLY, start, (size - start));
    eocd.order(ByteOrder.LITTLE_ENDIAN);
    index = (int) ((size - start) - ENDHDR);
    while (index > 0) {
      index--;
      eocd.position(index);
      if (isSignature(eocd, index, 5, 6)) {
        commentSize = (int) ((size - start) - ENDHDR) - index;
        eocdOffset = start + index;
        break;
      }
    }
  }
  checkSignature(path, eocd, index, 5, 6, "ENDSIG");
  int totalEntries = eocd.getChar(index + ENDTOT);
  long cdsize = UnsignedInts.toLong(eocd.getInt(index + ENDSIZ));
  int actualCommentSize = eocd.getChar(index + ENDCOM);
  if (commentSize != actualCommentSize) {
    throw new ZipException(
        String.format(
            "zip file comment length was %d, expected %d", commentSize, actualCommentSize));
  }
  // If the number of entries is 0xffff, check if the archive has a zip64 EOCD locator.
  if (totalEntries == ZIP64_MAGICCOUNT) {
    // Assume the zip64 EOCD has the usual size; we don't support zip64 extensible data sectors.
    long zip64eocdOffset = size - ENDHDR - ZIP64_LOCHDR - ZIP64_ENDHDR;
    MappedByteBuffer zip64eocd = chan.map(MapMode.READ_ONLY, zip64eocdOffset, ZIP64_ENDHDR);
    zip64eocd.order(ByteOrder.LITTLE_ENDIAN);
    // Note that zip reading is necessarily best-effort, since an archive could contain 0xFFFF
    // entries and the last entry's data could contain a ZIP64_ENDSIG. Some implementations
    // read the full EOCD records and compare them.
    if (zip64eocd.getInt(0) == ZIP64_ENDSIG) {
      cdsize = zip64eocd.getLong(ZIP64_ENDSIZ);
      eocdOffset = zip64eocdOffset;
    }
  }
  this.cd = chan.map(MapMode.READ_ONLY, eocdOffset - cdsize, cdsize);
  cd.order(ByteOrder.LITTLE_ENDIAN);
}
 

@Override
public StepExecutionResult execute(ExecutionContext context) throws IOException {
  try (FileChannel channel =
      FileChannel.open(
          getFilesystem().resolve(getPath()),
          StandardOpenOption.READ,
          StandardOpenOption.WRITE)) {
    MappedByteBuffer buffer = channel.map(READ_WRITE, 0, channel.size());
    Elf elf = new Elf(buffer);
    Elf.ElfSectionLookupResult sectionResult = elf.getMandatorySectionByName(getPath(), SECTION);
    int sectionIndex = sectionResult.getIndex();
    ElfSection section = sectionResult.getSection();

    // Parse the dynamic section.
    ElfDynamicSection dynamic = ElfDynamicSection.parse(elf.header.ei_class, section.body);

    // Generate a new dynamic section with only the whitelisted tags.
    ElfDynamicSection newDynamic =
        new ElfDynamicSection(
            RichStream.from(dynamic.entries)
                .filter(e -> isKeepTag(e.d_tag) || !isRemoveScrubbedTags())
                .map(e -> isKeepTag(e.d_tag) ? e : new ElfDynamicSection.Entry(e.d_tag, 0L))
                .toImmutableList());

    // Write out the new dynamic symbol table.
    section.body.rewind();
    newDynamic.write(elf.header.ei_class, section.body);

    // Update the size in other parts of the ELF file, if necessary.
    if (dynamic.entries.size() != newDynamic.entries.size()) {
      Preconditions.checkState(isRemoveScrubbedTags());

      // Update the section header.
      buffer.position((int) (elf.header.e_shoff + sectionIndex * elf.header.e_shentsize));
      section.header.withSize(section.body.position()).write(elf.header.ei_class, buffer);

      // Update the `_DYNAMIC` symbol in the symbol table.
      Optional<Elf.ElfSectionLookupResult> symtabSection = elf.getSectionByName(".symtab");
      if (symtabSection.isPresent()) {
        ElfSymbolTable symtab =
            ElfSymbolTable.parse(elf.header.ei_class, symtabSection.get().getSection().body);
        ElfSection strtab = elf.getMandatorySectionByName(getPath(), ".strtab").getSection();
        ElfSymbolTable newSymtab =
            new ElfSymbolTable(
                RichStream.from(symtab.entries)
                    .map(
                        entry ->
                            strtab.lookupString(entry.st_name).equals("_DYNAMIC")
                                ? entry.withSize(section.body.position())
                                : entry)
                    .toImmutableList());

        // Write out the new symbol table.
        symtabSection.get().getSection().body.rewind();
        newSymtab.write(elf.header.ei_class, symtabSection.get().getSection().body);
      }
    }
  }
  return StepExecutionResults.SUCCESS;
}
 

public static long countOccurrencesV5(Path path, String text) throws IOException {

        if (path == null || text == null) {
            throw new IllegalArgumentException("Path/text cannot be null");
        }

        if (text.isBlank()) {
            return 0;
        }

        final byte[] texttofind = text.getBytes(StandardCharsets.UTF_8);

        long count = 0;
        try (FileChannel fileChannel = FileChannel.open(path, StandardOpenOption.READ)) {

            long position = 0;
            long length = fileChannel.size();
            while (position < length) {

                long remaining = length - position;
                long bytestomap = (long) Math.min(MAP_SIZE, remaining);
                MappedByteBuffer mbBuffer = fileChannel.map(MapMode.READ_ONLY, position, bytestomap);

                long limit = mbBuffer.limit();
                long lastSpace = -1;
                long firstChar = -1;
                while (mbBuffer.hasRemaining()) {

                    boolean isFirstChar = false;
                    while (firstChar != 0 && mbBuffer.hasRemaining()) {

                        byte currentByte = mbBuffer.get();

                        if (Character.isWhitespace((char) currentByte)) {
                            lastSpace = mbBuffer.position();
                        }

                        if (texttofind[0] == currentByte) {
                            isFirstChar = true;
                            break;
                        }
                    }

                    if (isFirstChar) {

                        boolean isRestOfChars = true;

                        int j;
                        for (j = 1; j < texttofind.length; j++) {
                            if (!mbBuffer.hasRemaining() || texttofind[j] != mbBuffer.get()) {
                                isRestOfChars = false;
                                break;
                            }
                        }

                        if (isRestOfChars) {
                            count++;
                            lastSpace = -1;
                        }

                        firstChar = -1;
                    }
                }

                if (lastSpace > -1) {
                    position = position - (limit - lastSpace);
                }

                position += bytestomap;
            }
        }

        return count;
    }