DataInput and DataOutput interfaces to allow
* the reading and writing of Java primitives.
*
* @version 0.0
*
* @author Aaron M. Renn (arenn@urbanophile.com)
*/
public class RandomAccessFile implements DataOutput, DataInput
{
static
{
if (Configuration.INIT_LOAD_LIBRARY)
{
System.loadLibrary ("java-io");
}
}
/*************************************************************************/
/*
* Instance Variables
*/
/**
* The native file descriptor for this file
*/
private int native_fd;
/**
* Whether or not this file is open in read only mode
*/
private boolean read_only;
/*************************************************************************/
/*
* Constructors
*/
/**
* This method initializes a new instance of RandomAccessFile
* to read from the specified file name with the specified access mode.
* The access mode is either "r" for read only access or "rw" for read
* write access.
*
* Note that a SecurityManager check is made prior to
* opening the file to determine whether or not this file is allowed to
* be read or written.
*
* @param name The name of the file to read and/or write
* @param mode "r" for read only or "rw" for read-write access to the file
*
* @exception IllegalArgumentException If mode has an illegal value
* @exception SecurityException If the requested access to the file is not allowed
* @exception IOException If any other error occurs
*/
public
RandomAccessFile(String name, String mode) throws IllegalArgumentException,
SecurityException,
IOException
{
this(new File(name), mode);
}
/*************************************************************************/
/**
* This method initializes a new instance of RandomAccessFile
* to read from the specified File object with the specified
* access mode. The access mode is either "r" for read only access or "rw"
* for read-write access.
*
* Note that a SecurityManager check is made prior to
* opening the file to determine whether or not this file is allowed to
* be read or written.
*
* @param file The File object to read and/or write.
* @param mode "r" for read only or "rw" for read-write access to the file
*
* @exception IllegalArgumentException If mode has an illegal value
* @exception SecurityException If the requested access to the file is not allowed
* @exception IOException If any other error occurs
*/
public
RandomAccessFile(File file, String mode) throws IllegalArgumentException,
SecurityException,
IOException
{
// Check the mode
if (!mode.equals("r") && !mode.equals("rw"))
throw new IllegalArgumentException("Bad mode value: " + mode);
// The obligatory SecurityManager stuff
SecurityManager sm = System.getSecurityManager();
if (sm != null)
{
if (mode.equals("r"))
sm.checkRead(file.getPath());
else if (mode.equals("rw"))
sm.checkWrite(file.getPath());
}
if (mode.equals("r"))
read_only = true;
if (read_only)
native_fd = open(file.getPath(), true);
else
native_fd = open(file.getPath(), false);
}
/*************************************************************************/
/*
* Instance Methods
*/
/**
* This native method opens the file with the desired access mode
*/
private native int
open(String name, boolean read_only) throws IOException;
/*************************************************************************/
/**
* This method closes the file and frees up all file related system
* resources. Since most operating systems put a limit on how many files
* may be opened at any given time, it is a good idea to close all files
* when no longer needed to avoid hitting this limit
*/
public void
close() throws IOException
{
closeInternal(native_fd);
}
/*************************************************************************/
/**
* Native methods that actually closes the file
*/
private native void
closeInternal(int native_fd) throws IOException;
/*************************************************************************/
/**
* This method returns a FileDescriptor object that
* represents the native file handle for this file.
*
* @return The FileDescriptor object for this file
*
* @exception IOException If an error occurs
*/
public final FileDescriptor
getFD() throws IOException
{
return(new FileDescriptor(native_fd));
}
/*************************************************************************/
/**
* This method returns the current offset in the file at which the next
* read or write will occur
*
* @return The current file position
*
* @exception IOException If an error occurs
*/
public long
getFilePointer() throws IOException
{
return(getFilePointerInternal(native_fd));
}
/*************************************************************************/
/**
* This native method actually retrieves the file pointer
*/
private native long
getFilePointerInternal(int native_fd) throws IOException;
/*************************************************************************/
/**
* This method returns the length of the file in bytes
*
* @return The length of the file
*
* @exception IOException If an error occurs
*/
public long
length() throws IOException
{
return(lengthInternal(native_fd));
}
/*************************************************************************/
/**
* This native method determines the actual file length
*/
private native long
lengthInternal(int native_fd) throws IOException;
/*************************************************************************/
/**
* This method sets the current file position to the specified offset
* from the beginning of the file. Note that some operating systems will
* allow the file pointer to be set past the current end of the file.
*
* @param pos The offset from the beginning of the file at which to set the file pointer
*
* @exception IOException If an error occurs
*/
public void
seek(long pos) throws IOException
{
seekInternal(native_fd, pos);
}
/*************************************************************************/
/**
* This native method does the actual file offset seeking
*/
private native void
seekInternal(int native_fd, long pos) throws IOException;
/*************************************************************************/
/**
* This method sets the length of the file to the specified length. If
* the currently length of the file is longer than the specified length,
* then the file is truncated to the specified length. If the current
* length of the file is shorter than the specified length, the file
* is extended with bytes of an undefined value.
*
* The file must be open for write access for this operation to succeed.
*
* @param newlen The new length of the file
*
* @exception IOException If an error occurs
*/
public void
setLength(long newlen) throws IOException
{
if (read_only)
throw new IOException("File is open read only");
setLengthInternal(native_fd, newlen);
}
/*************************************************************************/
/**
* This native method does the actual work of setting the file length
*/
private native void
setLengthInternal(int native_fd, long newlen) throws IOException;
/*************************************************************************/
/**
* This method reads a single byte of data from the file and returns it
* as an integer.
*
* @return The byte read as an int, or -1 if the end of the file was reached.
*
* @exception IOException If an error occurs
*/
public int
read() throws IOException
{
byte[] buf = new byte[1];
int rc = readInternal(native_fd, buf, 0, buf.length);
if (rc == 0)
return(-1);
return(buf[0] & 0xFF);
}
/*************************************************************************/
/**
* This method reads bytes from the file into the specified array. The
* bytes are stored starting at the beginning of the array and up to
* buf.length bytes can be read.
*
* @param buf The buffer to read bytes from the file into
*
* @return The actual number of bytes read or -1 if end of file
*
* @exception IOException If an error occurs
*/
public int
read(byte[] buf) throws IOException
{
int rc = readInternal(native_fd, buf, 0, buf.length);
if (rc == 0)
return(-1);
else
return(rc);
}
/*************************************************************************/
/**
* This methods reads up to len bytes from the file into the s
* pecified array starting at position offset into the array.
*
* @param buf The array to read the bytes into
* @param offset The index into the array to start storing bytes
* @param len The requested number of bytes to read
*
* @param len The actual number of bytes read, or -1 if end of file
*
* @exception IOException If an error occurs
*/
public int
read(byte[] buf, int offset, int len) throws IOException
{
int rc = readInternal(native_fd, buf, offset, len);
if (rc == 0)
return(-1);
else
return(rc);
}
/*************************************************************************/
/**
* This native method actually reads the bytes from the file
*/
private native int
readInternal(int native_fd, byte[] buf, int offset, int len);
/*************************************************************************/
/**
* This method reads a Java boolean value from an input stream. It does
* so by reading a single byte of data. If that byte is zero, then the
* value returned is false If the byte is non-zero, then
* the value returned is true
*
* This method can read a boolean written by an object implementing the
* writeBoolean() method in the DataOutput interface.
*
* @return The boolean value read
*
* @exception EOFException If end of file is reached before reading the boolean
* @exception IOException If any other error occurs
*/
public final boolean
readBoolean() throws EOFException, IOException
{
int byte_read = read();
if (byte_read == -1)
throw new EOFException("Unexpected end of stream");
return(DataInputStream.convertToBoolean(byte_read));
}
/*************************************************************************/
/**
* This method reads a Java byte value from an input stream. The value
* is in the range of -128 to 127.
*
* This method can read a byte written by an object implementing the
* writeByte() method in the DataOutput interface.
*
* @return The byte value read
*
* @exception EOFException If end of file is reached before reading the byte
* @exception IOException If any other error occurs
*
* @see DataOutput
*/
public final byte
readByte() throws EOFException, IOException
{
int byte_read = read();
if (byte_read == -1)
throw new EOFException("Unexpected end of stream");
return(DataInputStream.convertToByte(byte_read));
}
/*************************************************************************/
/**
* This method reads 8 unsigned bits into a Java int value from the
* stream. The value returned is in the range of 0 to 255.
*
* This method can read an unsigned byte written by an object implementing the
* writeUnsignedByte() method in the DataOutput interface.
*
* @return The unsigned bytes value read as a Java int
*
* @exception EOFException If end of file is reached before reading the value
* @exception IOException If any other error occurs
*
* @see DataOutput
*/
public final int
readUnsignedByte() throws EOFException, IOException
{
int byte_read = read();
if (byte_read == -1)
throw new EOFException("Unexpected end of stream");
return(DataInputStream.convertToUnsignedByte(byte_read));
}
/*************************************************************************/
/**
* This method reads a Java char value from an input stream.
* It operates by reading two bytes from the stream and converting them to
* a single 16-bit Java char The two bytes are stored most
* significant byte first (i.e., "big endian") regardless of the native
* host byte ordering.
*
* As an example, if byte1 and code{byte2 represent the first
* and second byte read from the stream respectively, they will be
* transformed to a char in the following manner:
*
* (char)(((byte1 & 0xFF) << 8) | (byte2 & 0xFF)
*
* This method can read a char written by an object implementing the
* writeChar() method in the DataOutput interface.
*
* @return The char value read
*
* @exception EOFException If end of file is reached before reading the char
* @exception IOException If any other error occurs
*
* @see DataOutput
*/
public final char
readChar() throws EOFException, IOException
{
byte[] buf = new byte[2];
readFully(buf);
return(DataInputStream.convertToChar(buf));
}
/*************************************************************************/
/**
* This method reads a signed 16-bit value into a Java in from the stream.
* It operates by reading two bytes from the stream and converting them to
* a single 16-bit Java short The two bytes are stored most
* significant byte first (i.e., "big endian") regardless of the native
* host byte ordering.
*
* As an example, if byte1 and code{byte2 represent the first
* and second byte read from the stream respectively, they will be
* transformed to a short in the following manner:
*
* (short)(((byte1 & 0xFF) << 8) | (byte2 & 0xFF)
*
* The value returned is in the range of -32768 to 32767. *
* This method can read a short written by an object implementing the
* writeShort() method in the DataOutput interface.
*
* @return The short value read
*
* @exception EOFException If end of file is reached before reading the value
* @exception IOException If any other error occurs
*
* @see DataOutput
*/
public final short
readShort() throws EOFException, IOException
{
byte[] buf = new byte[2];
readFully(buf);
return(DataInputStream.convertToShort(buf));
}
/*************************************************************************/
/**
* This method reads 16 unsigned bits into a Java int value from the stream.
* It operates by reading two bytes from the stream and converting them to
* a single Java int The two bytes are stored most
* significant byte first (i.e., "big endian") regardless of the native
* host byte ordering.
*
* As an example, if byte1 and code{byte2 represent the first
* and second byte read from the stream respectively, they will be
* transformed to an int in the following manner:
*
* (int)(((byte1 & 0xFF) << 8) + (byte2 & 0xFF))
*
* The value returned is in the range of 0 to 65535. *
* This method can read an unsigned short written by an object implementing
* the writeUnsignedShort() method in the DataOutput interface.
*
* @return The unsigned short value read as a Java int
*
* @exception EOFException If end of file is reached before reading the value
* @exception IOException If any other error occurs
*/
public final int
readUnsignedShort() throws EOFException, IOException
{
byte[] buf = new byte[2];
readFully(buf);
return(DataInputStream.convertToUnsignedShort(buf));
}
/*************************************************************************/
/**
* This method reads a Java int value from an input stream
* It operates by reading four bytes from the stream and converting them to
* a single Java int The bytes are stored most
* significant byte first (i.e., "big endian") regardless of the native
* host byte ordering.
*
* As an example, if byte1 through byte4 represent the first
* four bytes read from the stream, they will be
* transformed to an int in the following manner:
*
* (int)(((byte1 & 0xFF) << 24) + ((byte2 & 0xFF) << 16) +
* ((byte3 & 0xFF) << 8) + (byte4 & 0xFF)))
*
* The value returned is in the range of 0 to 65535. *
* This method can read an int written by an object implementing the
* writeInt() method in the DataOutput interface.
*
* @return The int value read
*
* @exception EOFException If end of file is reached before reading the int
* @exception IOException If any other error occurs
*
* @see DataOutput
*/
public final int
readInt() throws EOFException, IOException
{
byte[] buf = new byte[4];
readFully(buf);
return(DataInputStream.convertToInt(buf));
}
/*************************************************************************/
/**
* This method reads a Java long value from an input stream
* It operates by reading eight bytes from the stream and converting them to
* a single Java long The bytes are stored most
* significant byte first (i.e., "big endian") regardless of the native
* host byte ordering.
*
* As an example, if byte1 through byte8 represent the first
* eight bytes read from the stream, they will be
* transformed to an long in the following manner:
*
* (long)((((long)byte1 & 0xFF) << 56) + (((long)byte2 & 0xFF) << 48) +
* (((long)byte3 & 0xFF) << 40) + (((long)byte4 & 0xFF) << 32) +
* (((long)byte5 & 0xFF) << 24) + (((long)byte6 & 0xFF) << 16) +
* (((long)byte7 & 0xFF) << 8) + ((long)byte9 & 0xFF)))
*
* The value returned is in the range of 0 to 65535. *
* This method can read an long written by an object implementing the
* writeLong() method in the DataOutput interface.
*
* @return The long value read
*
* @exception EOFException If end of file is reached before reading the long
* @exception IOException If any other error occurs
*
* @see DataOutput
*/
public final long
readLong() throws EOFException, IOException
{
byte[] buf = new byte[8];
readFully(buf);
return(DataInputStream.convertToLong(buf));
}
/*************************************************************************/
/**
* This method reads a Java float value from an input stream. It operates
* by first reading an int value from the stream by calling the
* readInt() method in this interface, then converts that int
* to a float using the intBitsToFloat method in
* the class java.lang.Float
*
* This method can read a float written by an object implementing the
* writeFloat() method in the DataOutput interface.
*
* @return The float value read
*
* @exception EOFException If end of file is reached before reading the float
* @exception IOException If any other error occurs
*
* @see java.lang.Float
* @see DataOutput
*/
public final float
readFloat() throws EOFException, IOException
{
int val = readInt();
return(Float.intBitsToFloat(val));
}
/*************************************************************************/
/**
* This method reads a Java double value from an input stream. It operates
* by first reading a logn value from the stream by calling the
* readLong() method in this interface, then converts that long
* to a double using the longBitsToDouble method in
* the class java.lang.Double
*
* This method can read a double written by an object implementing the
* writeDouble() method in the DataOutput interface.
*
* @return The double value read
*
* @exception EOFException If end of file is reached before reading the double
* @exception IOException If any other error occurs
*
* @see java.lang.Double
* @see DataOutput
*/
public final double
readDouble() throws EOFException, IOException
{
long val = readLong();
return(Double.longBitsToDouble(val));
}
/*************************************************************************/
/**
* This method reads the next line of text data from an input stream.
* It operates by reading bytes and converting those bytes to char
* values by treating the byte read as the low eight bits of the char
* and using 0 as the high eight bits. Because of this, it does
* not support the full 16-bit Unicode character set.
*
* The reading of bytes ends when either the end of file or a line terminator
* is encountered. The bytes read are then returned as a String
* A line terminator is a byte sequence consisting of either
* \r \n or \r\n These termination charaters are
* discarded and are not returned as part of the string.
*
* This method can read data that was written by an object implementing the
* writeLine() method in DataOutput
*
* @return The line read as a String
*
* @exception IOException If an error occurs
*
* @see DataOutput
*
* @deprecated
*/
public synchronized final String
readLine()
throws IOException
{
StringBuffer sb = new StringBuffer("");
for (;;)
{
int byte_read = read();
if (byte_read == -1)
return(sb.toString());
char c = (char)byte_read;
if (c == '\r')
{
byte_read = read();
if (((char)byte_read) != '\n')
seek(getFilePointer() - 1);
return(sb.toString());
}
if (c == '\n')
return(sb.toString());
sb.append(c);
}
}
/*************************************************************************/
/**
* This method reads a String from an input stream that is encoded in
* a modified UTF-8 format. This format has a leading two byte sequence
* that contains the remaining number of bytes to read. This two byte
* sequence is read using the readUnsignedShort() method of this
* interface.
*
* After the number of remaining bytes have been determined, these bytes
* are read an transformed into char values. These char values
* are encoded in the stream using either a one, two, or three byte format.
* The particular format in use can be determined by examining the first
* byte read.
*
* If the first byte has a high order bit of 0 then
* that character consists on only one byte. This character value consists
* of seven bits that are at positions 0 through 6 of the byte. As an
* example, if byte1 is the byte read from the stream, it would
* be converted to a char like so:
*
* (char)byte1
*
* If the first byte has 110 as its high order bits, then the
* character consists of two bytes. The bits that make up the character
* value are in positions 0 through 4 of the first byte and bit positions
* 0 through 5 of the second byte. (The second byte should have
* 10 as its high order bits). These values are in most significant
* byte first (i.e., "big endian") order.
*
* As an example, if byte1 and byte2 are the first two bytes
* read respectively, and the high order bits of them match the patterns
* which indicate a two byte character encoding, then they would be
* converted to a Java char like so:
*
* (char)(((byte1 & 0x1F) << 6) | (byte2 & 0x3F))
*
* If the first byte has a 1110 as its high order bits, then the
* character consists of three bytes. The bits that make up the character
* value are in positions 0 through 3 of the first byte and bit positions
* 0 through 5 of the other two bytes. (The second and third bytes should
* have 10 as their high order bits). These values are in most
* significant byte first (i.e., "big endian") order.
*
* As an example, if byte1 byte2 and byte3 are the
* three bytes read, and the high order bits of them match the patterns
* which indicate a three byte character encoding, then they would be
* converted to a Java char like so:
*
* (char)(((byte1 & 0x0F) << 12) | ((byte2 & 0x3F) << 6) | (byte3 & 0x3F))
*
* Note that all characters are encoded in the method that requires the
* fewest number of bytes with the exception of the character with the
* value of \u0000 which is encoded as two bytes. This is a
* modification of the UTF standard used to prevent C language style
* NUL values from appearing in the byte stream.
*
* This method can read data that was written by an object implementing the
* writeUTF() method in DataOutput
*
* @return The String read
*
* @exception EOFException If end of file is reached before reading the String
* @exception UTFDataFormatException If the data is not in UTF-8 format
* @exception IOException If any other error occurs
*
* @see DataOutput
*/
public synchronized final String
readUTF()
throws EOFException, UTFDataFormatException, IOException
{
StringBuffer sb = new StringBuffer("");
int num_bytes = readUnsignedShort();
byte[] buf = new byte[num_bytes];
readFully(buf);
return(DataInputStream.convertFromUTF(buf));
}
/*************************************************************************/
/**
* This method reads raw bytes into the passed array until the array is
* full. Note that this method blocks until the data is available and
* throws an exception if there is not enough data left in the stream to
* fill the buffer
*
* @param buf The buffer into which to read the data
*
* @exception EOFException If end of file is reached before filling the buffer
* @exception IOException If any other error occurs
*/
public final void
readFully(byte[] buf) throws EOFException, IOException
{
readFully(buf, 0, buf.length);
}
/*************************************************************************/
/**
* This method reads raw bytes into the passed array buf starting
* offset bytes into the buffer. The number of bytes read will be
* exactly len Note that this method blocks until the data is
* available and * throws an exception if there is not enough data left in
* the stream to read len bytes.
*
* @param buf The buffer into which to read the data
* @param offset The offset into the buffer to start storing data
* @param len The number of bytes to read into the buffer
*
* @exception EOFException If end of file is reached before filling the buffer
* @exception IOException If any other error occurs
*/
public synchronized final void
readFully(byte[] buf, int offset, int len)
throws EOFException, IOException
{
int total_read = 0;
while (total_read < len)
{
int bytes_read = read(buf, offset + total_read, len - total_read);
if (bytes_read == -1)
throw new EOFException("Unexpected end of stream");
total_read += bytes_read;
}
}
/*************************************************************************/
/**
* This method attempts to skip and discard the specified number of bytes
* in the input stream. It may actually skip fewer bytes than requested.
* The actual number of bytes skipped is returned. This method will not
* skip any bytes if passed a negative number of bytes to skip.
*
* @param num_bytes The requested number of bytes to skip.
*
* @return The number of bytes actually skipped.
*
* @exception IOException If an error occurs.
*/
public int
skipBytes(int n) throws EOFException, IOException
{
if (n <= 0)
return(0);
long total_skipped = skipInternal(native_fd, n);
return((int)n);
}
/*************************************************************************/
/*
* Native method that does the actual byte skipping.
*/
private native int
skipInternal(int native_fd, int n);
/*************************************************************************/
/**
* This method writes a single byte of data to the file. The file must
* be open for read-write in order for this operation to succeed.
*
* @param The byte of data to write, passed as an int.
*
* @exception IOException If an error occurs
*/
public void
write(int b) throws IOException
{
if (read_only)
throw new IOException("File is open read only");
byte[] buf = new byte[1];
buf[0] = (byte)b;
writeInternal(native_fd, buf, 0, buf.length);
}
/*************************************************************************/
/**
* This method writes all the bytes in the specified array to the file.
* The file must be open read-write in order for this operation to succeed.
*
* @param buf The array of bytes to write to the file
*/
public void
write(byte[] buf) throws IOException
{
if (read_only)
throw new IOException("File is open read only");
writeInternal(native_fd, buf, 0, buf.length);
}
/*************************************************************************/
/**
* This method writes len bytes to the file from the specified
* array starting at index offset into the array.
*
* @param buf The array of bytes to write to the file
* @param offset The index into the array to start writing file
* @param len The number of bytes to write
*
* @exception IOException If an error occurs
*/
public void
write(byte[] buf, int offset, int len) throws IOException
{
if (read_only)
throw new IOException("File is open read only");
writeInternal(native_fd, buf, offset, len);
}
/*************************************************************************/
/**
* This native method does the actual writing of the bytes
*/
private native void
writeInternal(int native_fd, byte[] buf, int offset, int len);
/*************************************************************************/
/**
* This method writes a Java boolean to the underlying output
* stream. For a value of true, 1 is written to the stream.
* For a value of false, 0 is written.
*
* @param b The boolean value to write to the stream
*
* @exception IOException If an error occurs
*/
public final void
writeBoolean(boolean b) throws IOException
{
int bool = DataOutputStream.convertFromBoolean(b);
write(bool);
}
/*************************************************************************/
/**
* This method writes a Java byte value to the underlying
* output stream.
*
* @param b The byte to write to the stream, passed as an int.
*
* @exception IOException If an error occurs
*/
public final void
writeByte(int b) throws IOException
{
write(b);
}
/*************************************************************************/
/**
* This method writes all the bytes in a String out to the
* stream. One byte is written for each character in the String.
* The high eight bits of each character are discarded.
*
* @param s The String to write to the stream
*
* @exception IOException If an error occurs
*/
public synchronized final void
writeBytes(String s)
throws IOException
{
if (s.length() == 0)
return;
byte[] buf = new byte[s.length()];
for (int i = 0; i < s.length(); i++)
buf[i] = (byte)(s.charAt(i) & 0xFF);
write(buf);
}
/*************************************************************************/
/**
* This method writes a single char value to the stream,
* high byte first.
*
* @param c The char value to write, passed as an int.
*
* @exception IOException If an error occurs
*/
public final void
writeChar(int c) throws IOException
{
write(DataOutputStream.convertFromChar(c));
}
/*************************************************************************/
/**
* This method writes all the characters in a String to the
* stream. There will be two bytes for each character value. The high
* byte of the character will be written first.
*
* @param s The String to write to the stream.
*
* @exception IOException If an error occurs
*/
public final void
writeChars(String s) throws IOException
{
if (s.length() == 0)
return;
byte[] buf = DataOutputStream.getConvertedStringChars(s);
write(buf);
}
/*************************************************************************/
/**
* This method writes a Java short to the stream, high byte
* first. This method requires two bytes to encode the value.
*
* @param s The short value to write to the stream, passed as an int.
*
* @exception IOException If an error occurs
*/
public final void
writeShort(int s) throws IOException
{
write(DataOutputStream.convertFromShort(s));
}
/*************************************************************************/
/**
* This method writes a Java int to the stream, high bytes
* first. This method requires four bytes to encode the value.
*
* @param i The int value to write to the stream.
*
* @exception IOException If an error occurs
*/
public final void
writeInt(int i) throws IOException
{
write(DataOutputStream.convertFromInt(i));
}
/*************************************************************************/
/**
* This method writes a Java long to the stream, high bytes
* first. This method requires eight bytes to encode the value.
*
* @param l The long value to write to the stream.
*
* @exception IOException If an error occurs
*/
public final void
writeLong(long l) throws IOException
{
write(DataOutputStream.convertFromLong(l));
}
/*************************************************************************/
/**
* This method writes a Java float value to the stream. This
* value is written by first calling the method Float.floatToIntBits
* to retrieve an int representing the floating point number,
* then writing this int value to the stream exactly the same
* as the writeInt() method does.
*
* @param f The floating point number to write to the stream.
*
* @exception IOException If an error occurs
*
* @see writeInt
*/
public final void
writeFloat(float f) throws IOException
{
int i = Float.floatToIntBits(f);
writeInt(i);
}
/*************************************************************************/
/**
* This method writes a Java double value to the stream. This
* value is written by first calling the method Double.doubleToLongBits
* to retrieve an long representing the floating point number,
* then writing this long value to the stream exactly the same
* as the writeLong() method does.
*
* @param d The double precision floating point number to write to the stream.
*
* @exception IOException If an error occurs
*
* @see writeLong
*/
public final void
writeDouble(double d) throws IOException
{
long l = Double.doubleToLongBits(d);
writeLong(l);
}
/*************************************************************************/
/**
* This method writes a Java String to the stream in a modified
* UTF-8 format. First, two bytes are written to the stream indicating the
* number of bytes to follow. Note that this is the number of bytes in the
* encoded String not the String length. Next
* come the encoded characters. Each character in the String
* is encoded as either one, two or three bytes. For characters in the
* range of \u0001 to \u007F, one byte is used. The character
* value goes into bits 0-7 and bit eight is 0. For characters in the range
* of \u0080 to \u007FF, two bytes are used. Bits
* 6-10 of the character value are encoded bits 0-4 of the first byte, with
* the high bytes having a value of "110". Bits 0-5 of the character value
* are stored in bits 0-5 of the second byte, with the high bits set to
* "10". This type of encoding is also done for the null character
* \u0000. This eliminates any C style NUL character values
* in the output. All remaining characters are stored as three bytes.
* Bits 12-15 of the character value are stored in bits 0-3 of the first
* byte. The high bits of the first bytes are set to "1110". Bits 6-11
* of the character value are stored in bits 0-5 of the second byte. The
* high bits of the second byte are set to "10". And bits 0-5 of the
* character value are stored in bits 0-5 of byte three, with the high bits
* of that byte set to "10".
*
* @param s The String to write to the output in UTF format
*
* @exception IOException If an error occurs
*/
public synchronized final void
writeUTF(String s)
throws IOException
{
byte[] buf = DataOutputStream.convertToUTF(s);
writeShort(buf.length);
write(buf);
}
/*************************************************************************/
/**
* This method creates a java.nio.channels.FileChannel.
* Nio does not allow one to create a file channel directly.
* A file channel must be created by first creating an instance of
* Input/Output/RandomAccessFile and invoking the getChannel() method on it.
*/
private FileChannel ch; /* cached associated file-channel */
public FileChannel
getChannel()
{
synchronized (this)
{
if (ch == null)
ch = new gnu.java.nio.FileChannelImpl(native_fd,
this);
}
return ch;
}
} // class RandomAccessFile