Package ghidra.app.util.bin

Class GhidraRandomAccessFile

java.lang.Object

ghidra.app.util.bin.GhidraRandomAccessFile

All Implemented Interfaces:

java.lang.AutoCloseable

public class GhidraRandomAccessFile
extends java.lang.Object
implements java.lang.AutoCloseable

Instances of this class support both reading and writing to a random access file. A random access file behaves like a large array of bytes stored in the file system. There is a kind of cursor, or index into the implied array, called the file pointer. This implementation relies on java.net.RandomAccessFile, but adds buffering to limit the amount.

Constructor Summary

Constructors

Constructor	Description
GhidraRandomAccessFile(java.io.File file, java.lang.String mode)	Creates a random access file stream to read from, and optionally to write to, the file specified by the File argument.

Method Summary

Modifier and Type	Method	Description
void	close()	Closes this random access file stream and releases any system resources associated with the stream.
protected void	finalize()
long	length()	Returns the length of this file.
int	read(byte[] b)	Reads up to b.length bytes of data from this file into an array of bytes.
int	read(byte[] b, int offset, int length)	Reads up to length bytes of data from this file into an array of bytes.
byte	readByte()	This method reads a byte from the file, starting from the current file pointer.
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	write(byte b)	Writes a byte to this file, starting at the current file pointer.
void	write(byte[] b)	Writes b.length bytes from the specified byte array to this file, starting at the current file pointer.
void	write(byte[] b, int offset, int length)	Writes a sub array as a sequence of bytes.

Methods inherited from class java.lang.Object

clone, equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Constructor Detail

GhidraRandomAccessFile

public GhidraRandomAccessFile(java.io.File file,
                              java.lang.String mode)
                       throws java.io.FileNotFoundException

Creates a random access file stream to read from, and optionally to write to, the file specified by the File argument. A new FileDescriptor object is created to represent this file connection.

This implementation relies on java.net.RandomAccessFile, but adds buffering to limit the amount.

The mode argument specifies the access mode in which the file is to be opened. The permitted values and their meanings are:

Access mode permitted values and meanings

Value	Meaning
"r"	Open for reading only. Invoking any of the write methods of the resulting object will cause an IOException to be thrown.
"rw"	Open for reading and writing. If the file does not already exist then an attempt will be made to create it.
"rws"	Open for reading and writing, as with "rw", and also require that every update to the file's content or metadata be written synchronously to the underlying storage device.
"rwd"	Open for reading and writing, as with "rw", and also require that every update to the file's content be written synchronously to the underlying storage device.

Parameters:

file - the file object

mode - the access mode, as described above

Throws:

java.lang.IllegalArgumentException - if the mode argument is not equal to one of "r", "rw", "rws", or "rwd"

java.io.FileNotFoundException - that name cannot be created, or if some other error occurs while opening or creating the file

Method Detail

finalize

protected void finalize()

Overrides:

finalize in class java.lang.Object

close

public void close()
           throws java.io.IOException

Closes this random access file stream and releases any system resources associated with the stream. A closed random access file cannot perform input or output operations and cannot be reopened.

If this file has an associated channel then the channel is closed as well.

Specified by:

close in interface java.lang.AutoCloseable

Throws:

java.io.IOException - if an I/O error occurs.

length

public long length()
            throws java.io.IOException

Returns the length of this file.

Returns:

the length of this file, measured in bytes.

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.

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.

readByte

public byte readByte()
              throws java.io.IOException

This method reads a byte from the file, starting from the current file pointer.

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

Returns:

the next byte of this file as a signed eight-bit byte.

Throws:

java.io.EOFException - if this file has reached the end.

java.io.IOException - if an I/O error occurs.

read

public int read(byte[] b)
         throws java.io.IOException

Reads up to b.length bytes of data from this file into an array of bytes. This method blocks until at least one byte of input is available.

Parameters:

b - the buffer into which the data is read.

Returns:

the total number of bytes read into the buffer, or -1 if there is no more data because the end of this file has been reached.

Throws:

java.io.IOException - if an I/O error occurs.

read

public int read(byte[] b,
                int offset,
                int length)
         throws java.io.IOException

Reads up to length bytes of data from this file into an array of bytes. This method blocks until at least one byte of input is available.

Parameters:

b - the buffer into which the data is read.

offset - the start offset of the data.

length - 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 file has been reached.

Throws:

java.io.IOException - if an I/O error occurs.

write

public void write(byte b)
           throws java.io.IOException

Writes a byte to this file, starting at the current file pointer.

Parameters:

b - the data.

Throws:

java.io.IOException - if an I/O error occurs.

write

public void write(byte[] b)
           throws java.io.IOException

Writes b.length bytes from the specified byte array to this file, starting at the current file pointer.

Parameters:

b - the data.

Throws:

java.io.IOException - if an I/O error occurs.

write

public void write(byte[] b,
                  int offset,
                  int length)
           throws java.io.IOException

Writes a sub array as a sequence of bytes.

Parameters:

b - the data to be written

offset - the start offset in the data

length - the number of bytes that are written

Throws:

java.io.IOException - If an I/O error has occurred.