Java FileInputStream.skip方法代码示例

import java.io.FileInputStream; //导入方法依赖的package包/类
public void WriteFile(File outputFile, int startFrame, int numFrames)
        throws java.io.IOException {
    outputFile.createNewFile();
    FileInputStream in = new FileInputStream(mInputFile);
    FileOutputStream out = new FileOutputStream(outputFile);
    int maxFrameLen = 0;
    for (int i = 0; i < numFrames; i++) {
        if (mFrameLens[startFrame + i] > maxFrameLen)
            maxFrameLen = mFrameLens[startFrame + i];
    }
    byte[] buffer = new byte[maxFrameLen];
    int pos = 0;
    for (int i = 0; i < numFrames; i++) {
        int skip = mFrameOffsets[startFrame + i] - pos;
        int len = mFrameLens[startFrame + i];
        if (skip > 0) {
            in.skip(skip);
            pos += skip;
        }
        in.read(buffer, 0, len);
        out.write(buffer, 0, len);
        pos += len;
    }
    in.close();
    out.close();
}
 

import java.io.FileInputStream; //导入方法依赖的package包/类
/**
 *  Skip toSkip number of bytes and return the remaining bytes of the file.
 */
private static long skipBytes(FileInputStream fis, int toSkip, long space)
        throws IOException {
    long skip = fis.skip(toSkip);
    if (skip != toSkip) {
        throw new RuntimeException("skip() returns " + skip
                                   + " but expected " + toSkip);
    }
    long newSpace = space - toSkip;
    long remaining = newSpace > 0 ? newSpace : 0;
    int avail = fis.available();
    if (avail != remaining) {
        throw new RuntimeException("available() returns " + avail
                                   + " but expected " + remaining);
    }

    System.out.println("Skipped " + skip + " bytes "
                       + " available() returns " + avail);
    return newSpace;
}
 

import java.io.FileInputStream; //导入方法依赖的package包/类
private static byte[] read(String inputFileName, int start, int end)
    throws FileNotFoundException, IOException {
  File theFile = new File(inputFileName);
  FileInputStream input = new FileInputStream(theFile);
  int skipped = 0;
  while (skipped < start) {
    skipped += input.skip(start - skipped);
  }
  int length = (int) (Math.min(end, theFile.length()) - start);
  byte[] bytes = new byte[length];
  int bytesRead = 0;
  while (bytesRead < bytes.length) {
    bytesRead = input.read(bytes, bytesRead, bytes.length - bytesRead);
    if (bytesRead == -1) {
      break;
    }
  }
  return bytes;
}
 

import java.io.FileInputStream; //导入方法依赖的package包/类
InputStreamAdapter(final File file, final long pos,
                   final long length)
                   throws FileNotFoundException, IOException {

    if (file == null) {
        throw new NullPointerException("file");
    }

    if (pos < 0) {
        throw new IllegalArgumentException("pos: " + pos);
    }

    if (length < 0) {
        throw new IllegalArgumentException("length: " + length);
    }

    final FileInputStream fis = new FileInputStream(file);

    if (pos > 0) {
        final long actualPos = fis.skip(pos);
    }

    final BufferedInputStream  bis = new BufferedInputStream(fis);
    final CountdownInputStream cis = new CountdownInputStream(bis);

    cis.setCount(length);

    m_countdownInputStream = cis;
}
 

import java.io.FileInputStream; //导入方法依赖的package包/类
@Override
public long open(DataSpec dataSpec) throws ContentDataSourceException {
  try {
    uriString = dataSpec.uri.toString();
    AssetFileDescriptor assetFd = resolver.openAssetFileDescriptor(dataSpec.uri, "r");
    inputStream = new FileInputStream(assetFd.getFileDescriptor());
    long skipped = inputStream.skip(dataSpec.position);
    if (skipped < dataSpec.position) {
      // We expect the skip to be satisfied in full. If it isn't then we're probably trying to
      // skip beyond the end of the data.
      throw new EOFException();
    }
    if (dataSpec.length != C.LENGTH_UNBOUNDED) {
      bytesRemaining = dataSpec.length;
    } else {
      bytesRemaining = inputStream.available();
      if (bytesRemaining == 0) {
        // FileInputStream.available() returns 0 if the remaining length cannot be determined, or
        // if it's greater than Integer.MAX_VALUE. We don't know the true length in either case,
        // so treat as unbounded.
        bytesRemaining = C.LENGTH_UNBOUNDED;
      }
    }
  } catch (IOException e) {
    throw new ContentDataSourceException(e);
  }

  opened = true;
  if (listener != null) {
    listener.onTransferStart();
  }

  return bytesRemaining;
}
 

import java.io.FileInputStream; //导入方法依赖的package包/类
public void WriteFile(File outputFile, int startFrame, int numFrames)
        throws java.io.IOException {
    outputFile.createNewFile();
    FileInputStream in = new FileInputStream(mInputFile);
    FileOutputStream out = new FileOutputStream(outputFile);

    byte[] header = new byte[6];
    header[0] = '#';
    header[1] = '!';
    header[2] = 'A';
    header[3] = 'M';
    header[4] = 'R';
    header[5] = '\n';
    out.write(header, 0, 6);

    int maxFrameLen = 0;
    for (int i = 0; i < numFrames; i++) {
        if (mFrameLens[startFrame + i] > maxFrameLen)
            maxFrameLen = mFrameLens[startFrame + i];
    }
    byte[] buffer = new byte[maxFrameLen];
    int pos = 0;
    for (int i = 0; i < numFrames; i++) {
        int skip = mFrameOffsets[startFrame + i] - pos;
        int len = mFrameLens[startFrame + i];
        if (skip < 0) {
            continue;
        }
        if (skip > 0) {
            in.skip(skip);
            pos += skip;
        }
        in.read(buffer, 0, len);
        out.write(buffer, 0, len);
        pos += len;
    }

    in.close();
    out.close();
}
 

import java.io.FileInputStream; //导入方法依赖的package包/类
public String computeMd5OfFirst10Frames()
        throws java.io.FileNotFoundException,
               java.io.IOException,
               java.security.NoSuchAlgorithmException {
    int[] frameOffsets = getFrameOffsets();
    int[] frameLens = getFrameLens();
    int numFrames = frameLens.length;
    if (numFrames > 10) {
        numFrames = 10;
    }

    MessageDigest digest = java.security.MessageDigest.getInstance("MD5");
    FileInputStream in = new FileInputStream(mInputFile);
    int pos = 0;
    for (int i = 0; i < numFrames; i++) {
        int skip = frameOffsets[i] - pos;
        int len = frameLens[i];
        if (skip > 0) {
            in.skip(skip);
            pos += skip;
        }
        byte[] buffer = new byte[len];
        in.read(buffer, 0, len);
        digest.update(buffer);
        pos += len;
    }
    in.close();
    byte[] hash = digest.digest();
    return bytesToHex(hash);
}
 

import java.io.FileInputStream; //导入方法依赖的package包/类
private static void verifyMac(MasterSecret masterSecret, File file) throws IOException {
  Mac             mac        = initializeMac(masterSecret.getMacKey());
  FileInputStream macStream  = new FileInputStream(file);
  InputStream     dataStream = new LimitedInputStream(new FileInputStream(file), file.length() - MAC_LENGTH);
  byte[]          theirMac   = new byte[MAC_LENGTH];

  if (macStream.skip(file.length() - MAC_LENGTH) != file.length() - MAC_LENGTH) {
    throw new IOException("Unable to seek");
  }

  readFully(macStream, theirMac);

  byte[] buffer = new byte[4096];
  int    read;

  while ((read = dataStream.read(buffer)) != -1) {
    mac.update(buffer, 0, read);
  }

  byte[] ourMac = mac.doFinal();

  if (!MessageDigest.isEqual(ourMac, theirMac)) {
    throw new IOException("Bad MAC");
  }

  macStream.close();
  dataStream.close();
}
 

import java.io.FileInputStream; //导入方法依赖的package包/类
@Override
public long open(DataSpec dataSpec) throws ContentDataSourceException {
  try {
    uri = dataSpec.uri;
    assetFileDescriptor = resolver.openAssetFileDescriptor(uri, "r");
    inputStream = new FileInputStream(assetFileDescriptor.getFileDescriptor());
    long skipped = inputStream.skip(dataSpec.position);
    if (skipped < dataSpec.position) {
      // We expect the skip to be satisfied in full. If it isn't then we're probably trying to
      // skip beyond the end of the data.
      throw new EOFException();
    }
    if (dataSpec.length != C.LENGTH_UNSET) {
      bytesRemaining = dataSpec.length;
    } else {
      bytesRemaining = inputStream.available();
      if (bytesRemaining == 0) {
        // FileInputStream.available() returns 0 if the remaining length cannot be determined, or
        // if it's greater than Integer.MAX_VALUE. We don't know the true length in either case,
        // so treat as unbounded.
        bytesRemaining = C.LENGTH_UNSET;
      }
    }
  } catch (IOException e) {
    throw new ContentDataSourceException(e);
  }

  opened = true;
  if (listener != null) {
    listener.onTransferStart(this, dataSpec);
  }

  return bytesRemaining;
}
 

import java.io.FileInputStream; //导入方法依赖的package包/类
/**
 * Serves file from homeDir and its' subdirectories (only). Uses only URI,
 * ignores all headers and HTTP parameters.
 */
private Response serveFile(Map<String, String> header, File file, String mime) {
    Response res;
    try {
        // Calculate etag
        String etag = Integer
                .toHexString((file.getAbsolutePath() + file.lastModified() + String.valueOf(file.length()))
                        .hashCode());

        // Support (simple) skipping:
        long startFrom = 0;
        long endAt = -1;
        String range = header.get("range");
        if (range != null && range.startsWith("bytes=")) {
            range = range.substring("bytes=".length());
            int minus = range.indexOf('-');
            try {
                if (minus > 0) {
                    startFrom = Long.parseLong(range.substring(0, minus));
                    endAt = Long.parseLong(range.substring(minus + 1));
                }
            } catch (NumberFormatException ignored) {
            }
        }

        // Change return code and add Content-Range header when skipping is
        // requested
        long fileLen = file.length();
        if (range != null && startFrom >= 0) {
            if (startFrom >= fileLen) {
                res = createResponse(Response.Status.RANGE_NOT_SATISFIABLE,
                        NanoHTTPD.MIME_PLAINTEXT, "");
                res.addHeader("Content-Range", "bytes 0-0/" + fileLen);
                res.addHeader("ETag", etag);
            } else {
                if (endAt < 0) {
                    endAt = fileLen - 1;
                }
                long newLen = endAt - startFrom + 1;
                if (newLen < 0) {
                    newLen = 0;
                }

                final long dataLen = newLen;
                FileInputStream fis = new FileInputStream(file) {
                    @Override
                    public int available() throws IOException {
                        return (int) dataLen;
                    }
                };
                long skipped = fis.skip(startFrom);
                if (skipped != startFrom) {
                    throw new IOException("unable to skip the required " + startFrom + " bytes.");
                }

                res = createResponse(Response.Status.PARTIAL_CONTENT, mime, fis);
                res.addHeader("Content-Length", String.valueOf(dataLen));
                res.addHeader("Content-Range", "bytes " + startFrom + "-" + endAt + "/"
                        + fileLen);
                res.addHeader("ETag", etag);
            }
        } else {
            if (etag.equals(header.get("if-none-match"))) {
                res = createResponse(Response.Status.NOT_MODIFIED, mime, "");
            } else {
                res = createResponse(Response.Status.OK, mime, new FileInputStream(file));
                res.addHeader("Content-Length", String.valueOf(fileLen));
                res.addHeader("ETag", etag);
            }
        }
    } catch (IOException ioe) {
        res = createResponse(Response.Status.FORBIDDEN, NanoHTTPD.MIME_PLAINTEXT,
                "FORBIDDEN: Reading file failed.");
    }

    return res;
}
 

import java.io.FileInputStream; //导入方法依赖的package包/类
/**
 * Serves file from homeDir and its' subdirectories (only). Uses only URI,
 * ignores all headers and HTTP parameters.
 */
Response serveFile(String uri, Map<String, String> header, File file, String mime) {
    Response res;
    try {
        // Calculate etag
        String etag = Integer
                .toHexString((file.getAbsolutePath() + file.lastModified() + String.valueOf(file.length()))
                        .hashCode());

        // Support (simple) skipping:
        long startFrom = 0;
        long endAt = -1;
        String range = header.get("range");
        if (range != null && range.startsWith("bytes=")) {
            range = range.substring("bytes=".length());
            int minus = range.indexOf('-');
            try {
                if (minus > 0) {
                    startFrom = Long.parseLong(range.substring(0, minus));
                    endAt = Long.parseLong(range.substring(minus + 1));
                }
            } catch (NumberFormatException ignored) {
            }
        }

        // Change return code and add Content-Range header when skipping is
        // requested
        long fileLen = file.length();
        if (range != null && startFrom >= 0) {
            if (startFrom >= fileLen) {
                res = createResponse(NanoHTTPD.Response.Status.RANGE_NOT_SATISFIABLE,
                        NanoHTTPD.MIME_PLAINTEXT, "");
                res.addHeader("Content-Range", "bytes 0-0/" + fileLen);
                res.addHeader("ETag", etag);
            } else {
                if (endAt < 0) {
                    endAt = fileLen - 1;
                }
                long newLen = endAt - startFrom + 1;
                if (newLen < 0) {
                    newLen = 0;
                }

                final long dataLen = newLen;
                FileInputStream fis = new FileInputStream(file) {
                    @Override
                    public int available() throws IOException {
                        return (int) dataLen;
                    }
                };
                long skipped = fis.skip(startFrom);
                if (skipped != startFrom) {
                    throw new IOException("unable to skip the required " + startFrom + " bytes.");
                }

                res = createResponse(NanoHTTPD.Response.Status.PARTIAL_CONTENT, mime, fis);
                res.addHeader("Content-Length", String.valueOf(dataLen));
                res.addHeader("Content-Range", "bytes " + startFrom + "-" + endAt + "/"
                        + fileLen);
                res.addHeader("ETag", etag);
            }
        } else {
            if (etag.equals(header.get("if-none-match"))) {
                res = createResponse(NanoHTTPD.Response.Status.NOT_MODIFIED, mime, "");
            } else {
                res = createResponse(NanoHTTPD.Response.Status.OK, mime, new FileInputStream(file));
                res.addHeader("Content-Length", String.valueOf(fileLen));
                res.addHeader("ETag", etag);
            }
        }
    } catch (IOException ioe) {
        res = createResponse(NanoHTTPD.Response.Status.FORBIDDEN, NanoHTTPD.MIME_PLAINTEXT,
                "FORBIDDEN: Reading file failed.");
    }

    return res;
}
 

import java.io.FileInputStream; //导入方法依赖的package包/类
public void ReadFile(File inputFile)
        throws java.io.FileNotFoundException,
        java.io.IOException {
    super.ReadFile(inputFile);
    mNumFrames = 0;
    mMaxFrames = 64;  // This will grow as needed
    mFrameOffsets = new int[mMaxFrames];
    mFrameLens = new int[mMaxFrames];
    mFrameGains = new int[mMaxFrames];
    mMinGain = 1000000000;
    mMaxGain = 0;
    mBitRate = 10;
    mOffset = 0;

    // No need to handle filesizes larger than can fit in a 32-bit int
    mFileSize = (int)mInputFile.length();

    if (mFileSize < 128) {
        throw new java.io.IOException("File too small to parse");
    }

    FileInputStream stream = new FileInputStream(mInputFile);
    byte[] header = new byte[12];
    stream.read(header, 0, 6);
    mOffset += 6;
    if (header[0] == '#' &&
        header[1] == '!' &&
        header[2] == 'A' &&
        header[3] == 'M' &&
        header[4] == 'R' &&
        header[5] == '\n') {
        parseAMR(stream, mFileSize - 6);
    }

    stream.read(header, 6, 6);
    mOffset += 6;

    if (header[4] == 'f' &&
        header[5] == 't' &&
        header[6] == 'y' &&
        header[7] == 'p' &&
        header[8] == '3' &&
        header[9] == 'g' &&
        header[10] == 'p' &&
        header[11] == '4') {

        int boxLen =
            ((0xff & header[0]) << 24) |
            ((0xff & header[1]) << 16) |
            ((0xff & header[2]) << 8) |
            ((0xff & header[3]));

        if (boxLen >= 4 && boxLen <= mFileSize - 8) {
            stream.skip(boxLen - 12);
            mOffset += boxLen - 12;
        }

        parse3gpp(stream, mFileSize - boxLen);
    }
}
 

import java.io.FileInputStream; //导入方法依赖的package包/类
/**
 * Test using the raw Inflater codec for reading gzip files.
 */
@Test
public void testPrototypeInflaterGzip() throws IOException {
  CompressionCodec gzip = new GzipCodec();  // used only for file extension
  localFs.delete(workDir, true);            // localFs = FileSystem instance

  System.out.println(COLOR_BR_BLUE + "testPrototypeInflaterGzip() using " +
    "non-native/Java Inflater and manual gzip header/trailer parsing" +
    COLOR_NORMAL);

  // copy prebuilt (correct!) version of concat.gz to HDFS
  final String fn = "concat" + gzip.getDefaultExtension();
  Path fnLocal = new Path(System.getProperty("test.concat.data", "/tmp"), fn);
  Path fnHDFS  = new Path(workDir, fn);
  localFs.copyFromLocalFile(fnLocal, fnHDFS);

  final FileInputStream in = new FileInputStream(fnLocal.toString());
  assertEquals("concat bytes available", 148, in.available());

  // should wrap all of this header-reading stuff in a running-CRC wrapper
  // (did so in BuiltInGzipDecompressor; see below)

  byte[] compressedBuf = new byte[256];
  int numBytesRead = in.read(compressedBuf, 0, 10);
  assertEquals("header bytes read", 10, numBytesRead);
  assertEquals("1st byte", 0x1f, compressedBuf[0] & 0xff);
  assertEquals("2nd byte", 0x8b, compressedBuf[1] & 0xff);
  assertEquals("3rd byte (compression method)", 8, compressedBuf[2] & 0xff);

  byte flags = (byte)(compressedBuf[3] & 0xff);
  if ((flags & 0x04) != 0) {   // FEXTRA
    numBytesRead = in.read(compressedBuf, 0, 2);
    assertEquals("XLEN bytes read", 2, numBytesRead);
    int xlen = ((compressedBuf[1] << 8) | compressedBuf[0]) & 0xffff;
    in.skip(xlen);
  }
  if ((flags & 0x08) != 0) {   // FNAME
    while ((numBytesRead = in.read()) != 0) {
      assertFalse("unexpected end-of-file while reading filename",
                  numBytesRead == -1);
    }
  }
  if ((flags & 0x10) != 0) {   // FCOMMENT
    while ((numBytesRead = in.read()) != 0) {
      assertFalse("unexpected end-of-file while reading comment",
                  numBytesRead == -1);
    }
  }
  if ((flags & 0xe0) != 0) {   // reserved
    assertTrue("reserved bits are set??", (flags & 0xe0) == 0);
  }
  if ((flags & 0x02) != 0) {   // FHCRC
    numBytesRead = in.read(compressedBuf, 0, 2);
    assertEquals("CRC16 bytes read", 2, numBytesRead);
    int crc16 = ((compressedBuf[1] << 8) | compressedBuf[0]) & 0xffff;
  }

  // ready to go!  next bytes should be start of deflated stream, suitable
  // for Inflater
  numBytesRead = in.read(compressedBuf);

  // Inflater docs refer to a "dummy byte":  no clue what that's about;
  // appears to work fine without one
  byte[] uncompressedBuf = new byte[256];
  Inflater inflater = new Inflater(true);

  inflater.setInput(compressedBuf, 0, numBytesRead);
  try {
    int numBytesUncompressed = inflater.inflate(uncompressedBuf);
    String outString =
      new String(uncompressedBuf, 0, numBytesUncompressed, "UTF-8");
    System.out.println("uncompressed data of first gzip member = [" +
                       outString + "]");
  } catch (java.util.zip.DataFormatException ex) {
    throw new IOException(ex.getMessage());
  }

  in.close();
}
 

import java.io.FileInputStream; //导入方法依赖的package包/类
public static void
main(
	String[]	args )
{
	try{
		final FileInputStream fis = new FileInputStream( "C:\\temp\\mp.part6.rar" );

		RARTOCDecoder decoder =
			new RARTOCDecoder(
				new DataProvider()
				{
					@Override
					public int
					read(
						byte[]		buffer )

						throws IOException
					{
						return( fis.read( buffer ));
					}

					@Override
					public void
					skip(
						long		bytes )

						throws IOException
					{
						fis.skip( bytes );
					}
				});

		decoder.analyse(
			new TOCResultHandler()
			{
				@Override
				public void
				entryRead(
					String		name,
					long		size,
					boolean		password )
				{
					System.out.println( name + ": " + size + (password?" protected":""));
				}

				@Override
				public void
				complete()
				{
					System.out.println( "complete" );
				}

				@Override
				public void
				failed(
					IOException error )
				{
					System.out.println( "failed: " + Debug.getNestedExceptionMessage( error ));
				}
			});

	}catch( Throwable e ){

		e.printStackTrace();
	}
}
 

import java.io.FileInputStream; //导入方法依赖的package包/类
/**
 * jumps the current chunk
 * @param e	FileInputStream
 * @return	false - always
 * @throws IOException error in FileInputStream
 */
public boolean jumpChunk(FileInputStream e) throws IOException {
	e.skip(length-6);
	return false;
}