Java RandomAccessFile.getFilePointer方法代码示例

import java.io.RandomAccessFile; //导入方法依赖的package包/类
private Date extractDate(RandomAccessFile raf) throws IOException {
	Date date = null;
	long pos = raf.getFilePointer();
	String line = readSubLine(raf);
	
	while (line != null && pos < Long.MAX_VALUE) {
		date = parseDate(line);
		
		if (date == null) {
			int c = goToNextLine(raf);
			pos = raf.getFilePointer();
			line = c != -1 ? readSubLine(raf) : null;
		} else {
			line = null;
		}
	}
	
	raf.seek(pos);
	
	return date;
}
 

import java.io.RandomAccessFile; //导入方法依赖的package包/类
public static void insertContent(String path, long offset, byte[] content) throws IOException {
  RandomAccessFile sourceRaf = new RandomAccessFile(path, "rw");
  File tempFile = FileUtil.createFile(path + ".tmp");
  RandomAccessFile tempRaf = new RandomAccessFile(tempFile, "rw");
  long fileSize = sourceRaf.length();
  FileChannel sourceChannel = sourceRaf.getChannel();
  FileChannel targetChannel = tempRaf.getChannel();
  long remaining = fileSize - offset;
  long position = offset;
  while (remaining > 0) {
    long transferred = sourceChannel.transferTo(position, remaining, targetChannel);
    remaining -= transferred;
    position += transferred;
  }
  sourceChannel.truncate(offset);
  sourceRaf.seek(offset);
  sourceRaf.write(content);
  long newOffset = sourceRaf.getFilePointer();
  targetChannel.position(0);
  sourceChannel.transferFrom(targetChannel, newOffset, (fileSize - offset));
  sourceChannel.close();
  targetChannel.close();
  FileUtil.deleteIfExists(tempFile);
}
 

import java.io.RandomAccessFile; //导入方法依赖的package包/类
/** todo - take account of incomplete addition of block due to lack of disk */

    // buggy database files had size == position == 0 at the end
    public static void restoreFile(String sourceName,
                                   String destName) throws IOException {

        RandomAccessFile source = new RandomAccessFile(sourceName, "r");
        RandomAccessFile dest   = new RandomAccessFile(destName, "rw");

        while (source.getFilePointer() != source.length()) {
            int    size     = source.readInt();
            long   position = source.readLong();
            byte[] buffer   = new byte[size];

            source.read(buffer);
            dest.seek(position);
            dest.write(buffer);
        }
        source.close();
        dest.close();
    }
 

import java.io.RandomAccessFile; //导入方法依赖的package包/类
public static RealChunk readChunk(RandomAccessFile raf)
		throws CannotReadException, IOException {
	final String id = Utils.readString(raf, 4);
	final int size = (int)Utils.readUint32(raf);
	if (size < 8) {
		throw new CannotReadException(
				"Corrupt file: RealAudio chunk length at position "
						+ (raf.getFilePointer() - 4)
						+ " cannot be less than 8");
	}
	if (size > (raf.length() - raf.getFilePointer() + 8)) {
		throw new CannotReadException(
				"Corrupt file: RealAudio chunk length of " + size
						+ " at position " + (raf.getFilePointer() - 4)
						+ " extends beyond the end of the file");
	}
	final byte[] bytes = new byte[size - 8];
	raf.readFully(bytes);
	return new RealChunk(id, size, bytes);
}
 

import java.io.RandomAccessFile; //导入方法依赖的package包/类
/**
 * get the next Packet from the RandomAccessFile
 * 
 * @param raf
 * @return - the Packet
 * @throws Exception
 */
public PacketSeek nextPacket(RandomAccessFile raf) throws Exception {
  String line = null;
  int count = 0;
  long pos = raf.getFilePointer();
  while ((line = raf.readLine()) != null) {
    Packet p = LogReader.lineAsPacket(line);
    if (p != null) {
      PacketSeek packetSeek = new PacketSeek();
      packetSeek.packet = p;
      packetSeek.pos = pos;
      return packetSeek;
    }
    pos = raf.getFilePointer();
    if (checkCountLimit("line", count++, false))
      return null;
  } // while
  return null;
}
 

import java.io.RandomAccessFile; //导入方法依赖的package包/类
public static MSPartialFile recreate(File file) throws IOException {
    if (!file.exists())
        throw new IOException("File does not exist");

    RandomAccessFile maskFile = new RandomAccessFile(file, "rw");

    RobustMML mml;
    try {
        mml = new RobustMML(maskFile.readUTF());
    } catch (MMLException ex) {
        throw new IOException("MML Meta data was badly formed. This file is corrupt.");
    }

    return new MSPartialFile(file, maskFile, new PartialFileHeader(mml, (int) maskFile
            .getFilePointer()));
}
 

import java.io.RandomAccessFile; //导入方法依赖的package包/类
private int readWordIndex(RandomAccessFile raf) throws IOException {
	String word = readWord(raf);
	if(raf.length()==raf.getFilePointer()) {
		return -1;
	}
	return searchVocab(word);
}
 

import java.io.RandomAccessFile; //导入方法依赖的package包/类
public static String readLineWithEOL(
                                      RandomAccessFile raf ) throws IOException {

    StringBuilder line = new StringBuilder();
    int c = -1;
    boolean eol = false;
    while (!eol) {
        switch (c = raf.read()) {
            case -1:
                eol = true;
                break;
            case '\n':
                eol = true;
                line.append('\n');
                break;
            case '\r':
                eol = true;
                line.append('\r');
                long cur = raf.getFilePointer();
                if ( (raf.read()) != '\n') {
                    raf.seek(cur);
                } else {
                    line.append('\n');
                }
                break;
            default:
                line.append((char) c);
                break;
        }
    }
    if (c == -1 && line.length() == 0) {
        return null;
    }
    return line.toString();
}
 

import java.io.RandomAccessFile; //导入方法依赖的package包/类
/**
 * Summarize all the ogg headers in a file
 * <p/>
 * A useful utility function
 *
 * @param oggFile
 * @throws CannotReadException
 * @throws IOException
 */
public void summarizeOggPageHeaders(File oggFile) throws CannotReadException, IOException {
    RandomAccessFile raf = new RandomAccessFile(oggFile, "r");

    while (raf.getFilePointer() < raf.length()) {
        System.out.println("pageHeader starts at absolute file position:" + raf.getFilePointer());
        OggPageHeader pageHeader = OggPageHeader.read(raf);
        System.out.println("pageHeader finishes at absolute file position:" + raf.getFilePointer());
        System.out.println(pageHeader + "\n");
        raf.seek(raf.getFilePointer() + pageHeader.getPageLength());
    }
    System.out.println("Raf File Pointer at:" + raf.getFilePointer() + "File Size is:" + raf.length());
    raf.close();
}
 

import java.io.RandomAccessFile; //导入方法依赖的package包/类
public void loadAllReferences() {
	try {
		RandomAccessFile raf = new RandomAccessFile(daaFile, "r");
		try {

			raf.seek(getLocationOfBlockInFile(refNamesBlockIndex));

			referenceNames = new byte[(int) dbSeqsUsed][];
			referenceLocations = new long[1 + ((int) dbSeqsUsed >>> referenceLocationChunkBits)];
			for (int i = 0; i < (int) dbSeqsUsed; i++) {
				if ((i & (referenceLocationChunkSize - 1)) == 0) {
					referenceLocations[i >>> referenceLocationChunkBits] = raf.getFilePointer();
				}
				int c = raf.read();
				while (c != 0)
					c = raf.read();
			}

			refLengths = new int[(int) dbSeqsUsed];
			for (int i = 0; i < dbSeqsUsed; i++) {
				ByteBuffer buffer = ByteBuffer.allocate(4);
				buffer.order(ByteOrder.LITTLE_ENDIAN);
				raf.read(buffer.array());
				refLengths[i] = buffer.getInt();
			}

		} finally {
			raf.close();
		}
	} catch (Exception e) {
		// TODO Auto-generated catch block
		e.printStackTrace();
	}
}
 

import java.io.RandomAccessFile; //导入方法依赖的package包/类
public static int fastSignInfo(File file) {
    int v1 = SIGNED_NOT;
    int v2 = SIGNED_NOT;
    try {
        ZipFile zip = new ZipFile(file);
        if (zip.getEntry("META-INF/CERT.RSA") != null) {
            v1 = SIGNED_V1;
        }
        Field archiveField = ZipFile.class.getDeclaredField("archive");
        archiveField.setAccessible(true);
        final RandomAccessFile archive = (RandomAccessFile) archiveField.get(zip);
        Method positionAtCentralDirectory = ZipFile.class.getDeclaredMethod("positionAtCentralDirectory");
        positionAtCentralDirectory.setAccessible(true);
        positionAtCentralDirectory.invoke(zip);
        long centralDirectoryOffset = archive.getFilePointer();
        archive.seek(centralDirectoryOffset - 24);
        byte[] buffer = new byte[24];
        archive.readFully(buffer);
        zip.close();
        ByteBuffer footer = ByteBuffer.wrap(buffer);
        footer.order(ByteOrder.LITTLE_ENDIAN);
        if ((footer.getLong(8) == APK_SIG_BLOCK_MAGIC_LO)
                && (footer.getLong(16) == APK_SIG_BLOCK_MAGIC_HI)) {
            v2 = SIGNED_V2;
        }

    } catch (IOException | NoSuchFieldException | SecurityException | IllegalArgumentException | IllegalAccessException | NoSuchMethodException | InvocationTargetException ex) {
    }
    return v1 | v2;
}
 

import java.io.RandomAccessFile; //导入方法依赖的package包/类
/**
 * Read next PageHeader from file
 *
 * @param raf
 * @return
 * @throws IOException
 * @throws CannotReadException
 */
public static OggPageHeader read(RandomAccessFile raf) throws IOException, CannotReadException {
    long start = raf.getFilePointer();
    logger.fine("Trying to read OggPage at:" + start);

    byte[] b = new byte[OggPageHeader.CAPTURE_PATTERN.length];
    raf.read(b);
    if (!(Arrays.equals(b, OggPageHeader.CAPTURE_PATTERN))) {
        raf.seek(start);
        if (AbstractID3v2Tag.isId3Tag(raf)) {
            logger.warning(ErrorMessage.OGG_CONTAINS_ID3TAG.getMsg(raf.getFilePointer() - start));
            raf.read(b);
            if ((Arrays.equals(b, OggPageHeader.CAPTURE_PATTERN))) {
                //Go to the end of the ID3 header
                start = raf.getFilePointer() - OggPageHeader.CAPTURE_PATTERN.length;
            }
        } else {
            throw new CannotReadException(ErrorMessage.OGG_HEADER_CANNOT_BE_FOUND.getMsg(new String(b)));
        }
    }

    raf.seek(start + OggPageHeader.FIELD_PAGE_SEGMENTS_POS);
    int pageSegments = raf.readByte() & 0xFF; //unsigned
    raf.seek(start);

    b = new byte[OggPageHeader.OGG_PAGE_HEADER_FIXED_LENGTH + pageSegments];
    raf.read(b);


    OggPageHeader pageHeader = new OggPageHeader(b);
    pageHeader.setStartByte(start);
    //Now just after PageHeader, ready for Packet Data
    return pageHeader;
}
 

import java.io.RandomAccessFile; //导入方法依赖的package包/类
/**
 * If Size is not even then we skip a byte, because chunks have to be aligned
 *
 * @param raf
 * @param chunkHeader
 * @throws java.io.IOException
 */
public static void ensureOnEqualBoundary(final RandomAccessFile raf,ChunkHeader chunkHeader) throws IOException
{
    if (Utils.isOddLength(chunkHeader.getSize()))
    {
        // Must come out to an even byte boundary unless at end of file
        if(raf.getFilePointer()<raf.length())
        {
            logger.config("Skipping Byte because on odd boundary");
            raf.skipBytes(1);
        }
    }
}
 

import java.io.RandomAccessFile; //导入方法依赖的package包/类
private boolean handleNextRecord(RecordUpdater recordUpdater, RandomAccessFile raf) throws IOException {
    // populate bytes
    if (raf.read(messageOffset) == -1) {
        // eof
        return false;
    }

    final long offset = getLong(messageOffset);

    raf.read(messageLength);

    final long crcOffset = raf.getFilePointer();
    raf.read(messageCrc);
    messageMagicValue = (byte) raf.read();

    // read past the 'attributes' byte which we don't care about
    byte attributes = (byte) raf.read();

    if (messageMagicValue > 0) {
        raf.read(messageTimestamp);
    }
    raf.read(messageKeyLength);

    final long messageKeyOffset = raf.getFilePointer();

    final int keyLength = getInteger(messageKeyLength);
    final byte[] messageKey;
    if (keyLength == -1) {
        messageKey = new byte[0];
    } else {
        messageKey = new byte[keyLength];
        raf.readFully(messageKey);
    }

    raf.readFully(messageValueLength);
    final long messageValueOffset = raf.getFilePointer();

    final int valueLength = getInteger(messageValueLength);
    final byte[] messageValue = new byte[valueLength];
    raf.readFully(messageValue);

    final long existingCrc = getLong(messageCrc);

    if (verifyCrc) {
        // could be turned on for verification
        final long calculatedCrc = calculateCrc(attributes, messageKey, messageValue);
        if (existingCrc != calculatedCrc) {
            throw new IllegalStateException("Invalid CRC value detected. Expected " + calculatedCrc
                    + " (calculated) but found " + existingCrc + " (in file)");
        }
    }

    if (recordUpdater != null && recordUpdater.update(offset, messageKey, messageValue)) {
        // Update CRC
        final long newCrc = calculateCrc(attributes, messageKey, messageValue);
        if (existingCrc != newCrc) {
            raf.seek(crcOffset);
            raf.write(getBytes(newCrc, messageCrc.length));
        }

        raf.seek(messageKeyOffset);
        raf.write(messageKey);
        raf.seek(messageValueOffset);
        raf.write(messageValue);

        logger.debug("Updated record with offset={} in segment file: {}", offset, file);

        recordsUpdated++;
    }
    return true;
}
 

import java.io.RandomAccessFile; //导入方法依赖的package包/类
private boolean getBlob(RandomAccessFile file, int offset,
        LookupRequest req) throws IOException {
    byte[] header = mBlobHeader;
    long oldPosition = file.getFilePointer();
    try {
        file.seek(offset);
        if (file.read(header) != BLOB_HEADER_SIZE) {
            Log.w(TAG, "cannot read blob header");
            return false;
        }
        long blobKey = readLong(header, BH_KEY);
        if (blobKey == 0) {
            return false; // This entry has been cleared.
        }
        if (blobKey != req.key) {
            Log.w(TAG, "blob key does not match: " + blobKey);
            return false;
        }
        int sum = readInt(header, BH_CHECKSUM);
        int blobOffset = readInt(header, BH_OFFSET);
        if (blobOffset != offset) {
            Log.w(TAG, "blob offset does not match: " + blobOffset);
            return false;
        }
        int length = readInt(header, BH_LENGTH);
        if (length < 0 || length > mMaxBytes - offset - BLOB_HEADER_SIZE) {
            Log.w(TAG, "invalid blob length: " + length);
            return false;
        }
        if (req.buffer == null || req.buffer.length < length) {
            req.buffer = new byte[length];
        }

        byte[] blob = req.buffer;
        req.length = length;

        if (file.read(blob, 0, length) != length) {
            Log.w(TAG, "cannot read blob data");
            return false;
        }
        if (checkSum(blob, 0, length) != sum) {
            Log.w(TAG, "blob checksum does not match: " + sum);
            return false;
        }
        return true;
    } catch (Throwable t)  {
        Log.e(TAG, "getBlob failed.", t);
        return false;
    } finally {
        file.seek(oldPosition);
    }
}