com.bigzip.plugin.compression.io
Class IOStream

java.lang.Object
  |
  +--com.bigzip.plugin.compression.io.AbstractStream
        |
        +--com.bigzip.plugin.compression.io.IOStream

public class IOStream
extends AbstractStream

This class is used for writing to and reading from data files. It also supports writing and reading in little endian bit order. These methods that support this order are denoted by an LE extension.
The .zip file format and compression scheme is the copyright of PKWARE, Inc.

See Also:

Field Summary
static int BIG_ENDIAN
           
static int LITTLE_ENDIAN
           
static int LONG32_INT16
           
static int LONG64_INT32
           
 
Fields inherited from class com.bigzip.plugin.compression.io.AbstractStream
clientStream
 
Constructor Summary
IOStream(java.io.RandomAccessFile raf)
          Creates an IO stream built on top of the specified underlying random access stream.
IOStream(java.io.RandomAccessFile raf, int typeSize, int typeFormat)
          Creates an IO stream built on top of the specified underlying random access stream.
 
Method Summary
 void close()
          Closes this random access stream and releases any system resources associated with the stream.
 void ensureOpen()
          Check to make sure that this stream has not been closed
 void finish()
          Required only to catch the the calls to super by inhereting streams.
 long getFilePointer()
          Returns the current offset in this file.
 java.io.RandomAccessFile getRandomAccessFile()
          Provides access the specified underlying random access stream.
 boolean isClosed()
           
 long length()
          Returns the length of this file.
 int read()
          Reads the next byte of data from this random access stream.
 int read(byte[] b, int off, int len)
          Reads up to len bytes of data from this random access stream into an array of bytes.
 boolean readBoolean()
          Reads a boolean from this file.
 byte readByte()
          Reads a signed 8-bit value from this file.
 char readChar()
          Reads a Unicode character from this file.
 int readDirect(byte[] b, int off, int len)
           
 double readDouble()
          Reads a double from this file.
 float readFloat()
          Reads a float from this file.
 void readFully(byte[] b, int off, int len)
          Reads exactly len bytes from this file into the byte array.
 int readInt()
          Reads a signed 32/16-bit integer from this file.
 int readInt(byte[] b, int off)
          Reads a signed 32/16-bit integer from a buffer.
 java.lang.String readLine()
          Reads the next line of text from this file.
 long readLong()
          Reads a signed 64/32-bit long from this file.
 long readLong(byte[] b, int off)
          Reads a signed 64/32-bit long from a buffer.
 short readShort()
          Reads a signed 16-bit number from this file.
 int readUnsignedByte()
          Reads an unsigned 8-bit number from this file.
 int readUnsignedShort()
          Reads an unsigned 16-bit number from this file.
 java.lang.String readUTF()
          Reads in a string from this file.
 void seek(long pos)
          Sets the file-pointer offset, measured from the beginning of this file, at which the next read or write occurs.
 void setClosed(boolean b)
          Sets the closed status of the file.
 void setRandomAccessFile(java.io.RandomAccessFile raf)
          Assigns a different IO stream built on top of the specified underlying random access stream.
 int skipBytes(int n)
          Attempts to skip over n bytes of input discarding the skipped bytes.
 void write(byte[] b)
          Writes b.length bytes to this random access stream.
 void write(byte[] b, int off, int len)
          Writes len bytes from the specified byte array starting at offset off to this random access stream.
 void write(int b)
          Writes the specified byte to this random access stream.
 void writeBoolean(boolean v)
          Writes a boolean to the file as a 1-byte value.
 void writeByte(int v)
          Writes a byte to the file as a 1-byte value.
 void writeBytes(java.lang.String s)
          Writes the string to the file as a sequence of bytes.
 void writeChar(int v)
          Writes a char to the file as a 2-byte value, high byte first.
 void writeChars(java.lang.String s)
          Writes a string to the file as a sequence of characters.
 void writeDirect(byte[] b, int off, int len)
           
 void writeDouble(double v)
          Converts the double argument to a long using the doubleToLongBits method in class Double, and then writes that long value to the file as an 8 or 4-byte quantity, high byte first.
 void writeFloat(float v)
          Converts the float argument to an int using the floatToIntBits method in class Float, and then writes that int value to the file as a 4 or 2-byte quantity, high byte first.
 void writeFully(byte[] b, int off, int len)
          Writes len bytes from the specified byte array starting at offset off to this random access stream.
 void writeInt(int v)
          Writes an int to the file.
 void writeLong(long v)
          Writes a long to the file.
 void writeShort(int v)
          Writes a short to the file as two bytes, high byte first.
 void writeUTF(java.lang.String str)
          Writes a string to the file using UTF-8 encoding in a machine-independent manner.
 
Methods inherited from class com.bigzip.plugin.compression.io.AbstractStream
read, readDirect, setClientStream, writeDirect
 
Methods inherited from class java.lang.Object
clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait
 

Field Detail

LONG32_INT16

public static final int LONG32_INT16

LONG64_INT32

public static final int LONG64_INT32

LITTLE_ENDIAN

public static final int LITTLE_ENDIAN

BIG_ENDIAN

public static final int BIG_ENDIAN
Constructor Detail

IOStream

public IOStream(java.io.RandomAccessFile raf)
Creates an IO stream built on top of the specified underlying random access stream. Bit size is set to 16 for int and 32 for long and data type byte format is set to little endian.

The stream will default to java standard bits and order for data types. ie. BIG_ENDIAN and LONG64_INT32

Parameters:
raf - the underlying random access stream to be assigned to the field this.raf for later use.

IOStream

public IOStream(java.io.RandomAccessFile raf,
                int typeSize,
                int typeFormat)
Creates an IO stream built on top of the specified underlying random access stream.
Parameters:
raf - the underlying random access stream to be assigned to the field this.raf for later use.
typeSize - the bit size of integers and longs.
typeFormat - the byte format of data types, little or big endian.
See Also:
bigzip.plugin.compression.io.IOStream#LONG64_INT32, bigzip.plugin.compression.io.IOStream#LONG32_INT16, bigzip.plugin.compression.io.IOStream#BIG_ENDIAN, bigzip.plugin.compression.io.IOStream#LITTLE_ENDIAN
Method Detail

getRandomAccessFile

public java.io.RandomAccessFile getRandomAccessFile()
Provides access the specified underlying random access stream.
Returns:
raf the underlying random access stream assigned to the field this.raf.

setRandomAccessFile

public void setRandomAccessFile(java.io.RandomAccessFile raf)
Assigns a different IO stream built on top of the specified underlying random access stream.
Parameters:
raf - the underlying random access stream to be assigned to the field this.raf for later use.

isClosed

public boolean isClosed()
Overrides:
isClosed in class AbstractStream
Returns:
the closed status of the file.

setClosed

public void setClosed(boolean b)
Sets the closed status of the file.
Overrides:
setClosed in class AbstractStream
Parameters:
b - closed status.

ensureOpen

public void ensureOpen()
                throws java.io.IOException
Check to make sure that this stream has not been closed
Overrides:
ensureOpen in class AbstractStream
Throws:
java.io.IOException - If the stream is no longer opened

read

public int read()
         throws java.io.IOException
Reads the next byte of data from this random access stream. The value byte is returned as an int in the range 0 to 255. If no byte is available because the end of the stream has been reached, the value -1 is returned. This method blocks until input data is available, the end of the stream is detected, or an exception is thrown.

This method simply performs raf.read() and returns the result.

Overrides:
read in class AbstractStream
Returns:
the next byte of data, or -1 if the end of the stream is reached.
Throws:
java.io.IOException - if an I/O error occurs.
See Also:
com.shaik.bigzip.archive.zip.IOStream#raf

read

public int read(byte[] b,
                int off,
                int len)
         throws java.io.IOException
Reads up to len bytes of data from this random access stream into an array of bytes. This method blocks until some input is available.

This method simply performs raf.read(b, off, len) and returns the result.

Overrides:
read in class AbstractStream
Parameters:
b - the buffer into which the data is read.
off - the start offset of the data.
len - the maximum number of bytes read.
Returns:
the total number of bytes read into the buffer, or -1 if there is no more data because the end of the stream has been reached.
Throws:
java.io.IOException - if an I/O error occurs.
See Also:
com.shaik.bigzip.archive.zip.IOStream#in

readFully

public void readFully(byte[] b,
                      int off,
                      int len)
               throws java.io.IOException
Reads exactly len bytes from this file into the byte array. This method reads repeatedly from the file until all the bytes are read. This method blocks until all the bytes are read, the end of the stream is detected, or an exception is thrown.
Overrides:
readFully in class AbstractStream
Parameters:
b - the buffer into which the data is read.
off - the start offset of the data.
len - the number of bytes to read.
Throws:
java.io.EOFException - if this file reaches the end before reading all the bytes.
java.io.IOException - if an I/O error occurs.

readDirect

public int readDirect(byte[] b,
                      int off,
                      int len)
               throws java.io.IOException
Overrides:
readDirect in class AbstractStream

write

public void write(int b)
           throws java.io.IOException
Writes the specified byte to this random access stream.

The write method of IOStream calls the write method of its underlying random access stream, that is, it performs raf.write(b).

Implements the write method of RandomAccessFile.

Overrides:
write in class AbstractStream
Parameters:
b - the byte.
Throws:
java.io.IOException - if an I/O error occurs.

write

public void write(byte[] b)
           throws java.io.IOException
Writes b.length bytes to this random access stream.

The write method of IOStream calls its write method of three arguments with the arguments b, 0, and b.length.

Note that this method does not call the one-argument write method of its underlying stream with the single argument b.

Overrides:
write in class AbstractStream
Parameters:
b - the data to be written.
Throws:
java.io.IOException - if an I/O error occurs.
See Also:
com.shaik.bigzip.archive.zip.IOStream#write(byte[], int, int)

write

public void write(byte[] b,
                  int off,
                  int len)
           throws java.io.IOException
Writes len bytes from the specified byte array starting at offset off to this random access stream.

The write method of IOStream calls the write method of one argument on each byte to output.

Note that this method does not call the write method of its underlying random access stream with the same arguments. Subclasses of IOStream should provide a more efficient implementation of this method.

Overrides:
write in class AbstractStream
Parameters:
b - the data.
off - the start offset in the data.
len - the number of bytes to write.
Throws:
java.io.IOException - if an I/O error occurs.
See Also:
com.shaik.bigzip.archive.zip.IOStream#write(int)

writeFully

public void writeFully(byte[] b,
                       int off,
                       int len)
                throws java.io.IOException
Writes len bytes from the specified byte array starting at offset off to this random access stream.

The write method of IOStream calls the write method of one argument on each byte to output.

Note that this method does not call the write method of its underlying random access stream with the same arguments. Subclasses of IOStream should provide a more efficient implementation of this method.

Overrides:
writeFully in class AbstractStream
Parameters:
b - the data.
off - the start offset in the data.
len - the number of bytes to write.
Throws:
java.io.IOException - if an I/O error occurs.
See Also:
com.shaik.bigzip.archive.zip.IOStream#write(int)

writeDirect

public void writeDirect(byte[] b,
                        int off,
                        int len)
                 throws java.io.IOException
Overrides:
writeDirect in class AbstractStream

skipBytes

public int skipBytes(int n)
              throws java.io.IOException
Attempts to skip over n bytes of input discarding the skipped bytes.

This method may skip over some smaller number of bytes, possibly zero. This may result from any of a number of conditions; reaching end of file before n bytes have been skipped is only one possibility. This method never throws an EOFException. The actual number of bytes skipped is returned. If n is negative, no bytes are skipped.

Overrides:
skipBytes in class AbstractStream
Parameters:
n - the number of bytes to be skipped.
Returns:
the actual number of bytes skipped.
Throws:
java.io.IOException - if an I/O error occurs.

close

public void close()
           throws java.io.IOException
Closes this random access stream and releases any system resources associated with the stream.

The close method of IOStream calls its flush method, and then calls the close method of its underlying random access stream.

Overrides:
close in class AbstractStream
Throws:
java.io.IOException - if an I/O error occurs.

getFilePointer

public long getFilePointer()
                    throws java.io.IOException
Returns the current offset in this file.
Overrides:
getFilePointer in class AbstractStream
Returns:
the offset from the beginning of the file, in bytes, at which the next read or write occurs.
Throws:
java.io.IOException - if an I/O error occurs.

seek

public void seek(long pos)
          throws java.io.IOException
Sets the file-pointer offset, measured from the beginning of this file, at which the next read or write occurs. The offset may be set beyond the end of the file. Setting the offset beyond the end of the file does not change the file length. The file length will change only by writing after the offset has been set beyond the end of the file.
Overrides:
seek in class AbstractStream
Parameters:
pos - the offset position, measured in bytes from the beginning of the file, at which to set the file pointer.
Throws:
java.io.IOException - if pos is less than 0 or if an I/O error occurs.

length

public long length()
            throws java.io.IOException
Returns the length of this file.
Overrides:
length in class AbstractStream
Returns:
the length of this file, measured in bytes.
Throws:
java.io.IOException - if an I/O error occurs.

finish

public void finish()
            throws java.io.IOException
Required only to catch the the calls to super by inhereting streams.
Overrides:
finish in class AbstractStream

readBoolean

public boolean readBoolean()
                    throws java.io.IOException
Reads a boolean from this file. This method reads a single byte from the file. A value of 0 represents false. Any other value represents true. This method blocks until the byte is read, the end of the stream is detected, or an exception is thrown.
Overrides:
readBoolean in class AbstractStream
Returns:
the boolean value read.
Throws:
java.io.EOFException - if this file has reached the end.
java.io.IOException - if an I/O error occurs.

readByte

public byte readByte()
              throws java.io.IOException
Reads a signed 8-bit value from this file. This method reads a byte from the file. If the byte read is b, where 0 <= b <= 255, then the result is:

This method blocks until the byte is read, the end of the stream is detected, or an exception is thrown.

Overrides:
readByte in class AbstractStream
Returns:
the next byte of this file as a signed 8-bit byte.
Throws:
java.io.EOFException - if this file has reached the end.
java.io.IOException - if an I/O error occurs.

readUnsignedByte

public int readUnsignedByte()
                     throws java.io.IOException
Reads an unsigned 8-bit number from this file. This method reads a byte from this file and returns that byte.

This method blocks until the byte is read, the end of the stream is detected, or an exception is thrown.

Overrides:
readUnsignedByte in class AbstractStream
Returns:
the next byte of this file, interpreted as an unsigned 8-bit number.
Throws:
java.io.EOFException - if this file has reached the end.
java.io.IOException - if an I/O error occurs.
Since:
JDK1.0

readShort

public final short readShort()
                      throws java.io.IOException
Reads a signed 16-bit number from this file. The method reads 2 bytes from this file.

This method blocks until the two bytes are read, the end of the stream is detected, or an exception is thrown.

Overrides:
readShort in class AbstractStream
Returns:
the next two bytes of this file, interpreted as a signed 16-bit number.
Throws:
java.io.EOFException - if this file reaches the end before reading two bytes.
java.io.IOException - if an I/O error occurs.

readUnsignedShort

public final int readUnsignedShort()
                            throws java.io.IOException
Reads an unsigned 16-bit number from this file. This method reads two bytes from the file.

This method blocks until the two bytes are read, the end of the stream is detected, or an exception is thrown.

Overrides:
readUnsignedShort in class AbstractStream
Returns:
the next two bytes of this file, interpreted as an unsigned 16-bit integer.
Throws:
java.io.EOFException - if this file reaches the end before reading two bytes.
java.io.IOException - if an I/O error occurs.

readChar

public char readChar()
              throws java.io.IOException
Reads a Unicode character from this file. This method reads two bytes from the file.

This method blocks until the two bytes are read, the end of the stream is detected, or an exception is thrown.

Overrides:
readChar in class AbstractStream
Returns:
the next two bytes of this file as a Unicode character.
Throws:
java.io.EOFException - if this file reaches the end before reading two bytes.
java.io.IOException - if an I/O error occurs.

readInt

public final int readInt()
                  throws java.io.IOException
Reads a signed 32/16-bit integer from this file. This method reads 4/2 bytes from the file.

This method blocks until the four bytes are read, the end of the stream is detected, or an exception is thrown.

Overrides:
readInt in class AbstractStream
Returns:
the next four bytes of this file, interpreted as an int.
Throws:
java.io.EOFException - if this file reaches the end before reading four bytes.
java.io.IOException - if an I/O error occurs.

readInt

public int readInt(byte[] b,
                   int off)
Reads a signed 32/16-bit integer from a buffer. This method reads 4/2 bytes from the buffer.
Overrides:
readInt in class AbstractStream
Parameters:
b - The byte array containing the value
off - The starting position of the value in the array
Returns:
the next four bytes of this file, interpreted as an int.

readLong

public long readLong()
              throws java.io.IOException
Reads a signed 64/32-bit long from this file. This method reads eight/four bytes from the file.

This method blocks until the eight bytes are read, the end of the stream is detected, or an exception is thrown.

Overrides:
readLong in class AbstractStream
Returns:
the next eight bytes of this file, interpreted as a long.
Throws:
java.io.EOFException - if this file reaches the end before reading eight bytes.
java.io.IOException - if an I/O error occurs.

readLong

public long readLong(byte[] b,
                     int off)
Reads a signed 64/32-bit long from a buffer. This method reads eight/four bytes from the buffer.
Overrides:
readLong in class AbstractStream
Parameters:
b - The byte array containing the value
off - The starting position of the value in the array
Returns:
the next eight bytes of this file, interpreted as a long.

readFloat

public float readFloat()
                throws java.io.IOException
Reads a float from this file. This method reads an int value as if by the readInt method and then converts that int to a float using the intBitsToFloat method in class Float.

This method blocks until the four bytes are read, the end of the stream is detected, or an exception is thrown.

Overrides:
readFloat in class AbstractStream
Returns:
the next four/two bytes of this file, interpreted as a float.

readDouble

public double readDouble()
                  throws java.io.IOException
Reads a double from this file. This method reads a long value as if by the readLong method and then converts that long to a double using the longBitsToDouble method in class Double.

This method blocks until the eight bytes are read, the end of the stream is detected, or an exception is thrown.

Overrides:
readDouble in class AbstractStream
Returns:
the next eight/four bytes of this file, interpreted as a double.

readLine

public java.lang.String readLine()
                          throws java.io.IOException
Reads the next line of text from this file. This method successively reads bytes from the file until it reaches the end of a line of text.

This method blocks until a newline character is read, a carriage return and the byte following it are read (to see if it is a newline), the end of the stream is detected, or an exception is thrown.

Overrides:
readLine in class AbstractStream
Returns:
the next line of text from this file.

readUTF

public java.lang.String readUTF()
                         throws java.io.IOException
Reads in a string from this file. The string has been encoded using a modified UTF-8 format.
Overrides:
readUTF in class AbstractStream
Returns:
a Unicode string.

writeBoolean

public void writeBoolean(boolean v)
                  throws java.io.IOException
Writes a boolean to the file as a 1-byte value. The value true is written out as the value (byte)1; the value false is written out as the value (byte)0.
Overrides:
writeBoolean in class AbstractStream
Parameters:
v - a boolean value to be written.

writeByte

public void writeByte(int v)
               throws java.io.IOException
Writes a byte to the file as a 1-byte value.
Overrides:
writeByte in class AbstractStream
Parameters:
v - a byte value to be written.

writeShort

public void writeShort(int v)
                throws java.io.IOException
Writes a short to the file as two bytes, high byte first.
Overrides:
writeShort in class AbstractStream
Parameters:
v - a short to be written.

writeChar

public void writeChar(int v)
               throws java.io.IOException
Writes a char to the file as a 2-byte value, high byte first.
Overrides:
writeChar in class AbstractStream
Parameters:
v - a char value to be written.

writeInt

public void writeInt(int v)
              throws java.io.IOException
Writes an int to the file.
Overrides:
writeInt in class AbstractStream
Parameters:
v - an int to be written.
Throws:
java.io.IOException - if an I/O error occurs.

writeLong

public void writeLong(long v)
               throws java.io.IOException
Writes a long to the file.
Overrides:
writeLong in class AbstractStream
Parameters:
v - a long to be written.
Throws:
java.io.IOException - if an I/O error occurs.

writeFloat

public void writeFloat(float v)
                throws java.io.IOException
Converts the float argument to an int using the floatToIntBits method in class Float, and then writes that int value to the file as a 4 or 2-byte quantity, high byte first.
Overrides:
writeFloat in class AbstractStream
Parameters:
v - a float value to be written.

writeDouble

public void writeDouble(double v)
                 throws java.io.IOException
Converts the double argument to a long using the doubleToLongBits method in class Double, and then writes that long value to the file as an 8 or 4-byte quantity, high byte first.
Overrides:
writeDouble in class AbstractStream
Parameters:
v - a double value to be written.

writeBytes

public void writeBytes(java.lang.String s)
                throws java.io.IOException
Writes the string to the file as a sequence of bytes. Each character in the string is written out, in sequence, by discarding its high eight bits.
Overrides:
writeBytes in class AbstractStream
Parameters:
s - a string of bytes to be written.

writeChars

public void writeChars(java.lang.String s)
                throws java.io.IOException
Writes a string to the file as a sequence of characters. Each character is written to the data output stream as if by the writeChar method.
Overrides:
writeChars in class AbstractStream
Parameters:
s - a String value to be written.

writeUTF

public void writeUTF(java.lang.String str)
              throws java.io.IOException
Writes a string to the file using UTF-8 encoding in a machine-independent manner.
Overrides:
writeUTF in class AbstractStream
Parameters:
str - a string to be written.