org.rigwit.forth

Class ForthStreamReader

java.lang.Object

org.rigwit.forth.ForthReader

org.rigwit.forth.ForthStreamReader

public class ForthStreamReader
extends ForthReader

Read the input from an input stream, buffering one line at a time.

Field Summary

Fields inherited from class org.rigwit.forth.ForthReader

bufferSize, description, lineNumber, position

Constructor Summary

Constructors

Constructor and Description
ForthStreamReader(java.io.Reader reader, java.lang.String title) Initialise the reader with a given input stream and input source description.

Method Summary

Methods

Modifier and Type	Method and Description
protected int	charAt(int off) Return the character at the given offset into the buffer or -1 if the character is unavailable.
void	close() Close the input stream.
int	read() Reads a single character.
boolean	ready() Determines whether this stream is ready to be read.
boolean	refill() Attempt to fill the input buffer from the input source, and return true if successful.
ForthReader	restoreInput(VM vm) Restore the current input environment from the system stack.
void	saveInput(VM vm) Save the current input parameters on the system stack.

Methods inherited from class org.rigwit.forth.ForthReader

backup, getBase, getDescription, getLineNumber, getPosition, isEmpty, setLineNumber, setPosition, size

Methods inherited from class java.lang.Object

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

Constructor Detail

ForthStreamReader

public ForthStreamReader(java.io.Reader reader,
                 java.lang.String title)

Initialise the reader with a given input stream and input source description.

Parameters:

reader - the input reader to be used for input.

title - the input source description to be used in error reports.

Method Detail

read

public int read()
         throws java.io.IOException

Description copied from class: ForthReader

Reads a single character.

Specified by:

read in class ForthReader

Returns:

The character read, as an integer in the range 0x00-0xffff, or -1 if the end of the stream has been reached.

Throws:

java.io.IOException - when there is a problem reading the input stream.

ready

public boolean ready()
              throws java.io.IOException

Description copied from class: ForthReader

Determines whether this stream is ready to be read. The input stream is ready if the buffer is not empty, or if the underlying character stream is ready.

Overrides:

ready in class ForthReader

Returns:

true if the input stream can be read and false if it can not.

Throws:

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

close

public void close()
           throws java.io.IOException

Description copied from class: ForthReader

Close the input stream.

Specified by:

close in class ForthReader

Throws:

java.io.IOException

charAt

protected int charAt(int off)

Description copied from class: ForthReader

Return the character at the given offset into the buffer or -1 if the character is unavailable. A character may be unavailable if the offset is outwith the buffer, or if the input stream is out of characters.

Specified by:

charAt in class ForthReader

Parameters:

off - the offset from the start of the buffer to obtain a character.

Returns:

The character at the given offset or -1 if the character is not available.

saveInput

public void saveInput(VM vm)

Save the current input parameters on the system stack. Called by the save-input function. Place all of the parameters on the data stack followed by the number of parameters.

The mark interface is used if the reader supports it.

Specified by:

saveInput in class ForthReader

Parameters:

vm - the virtual machine to use when saving the current input environment.

restoreInput

public ForthReader restoreInput(VM vm)

Restore the current input environment from the system stack. Called by the restore-input function. This is the counter part to the saveInput() method. The top of the stack holds the number of parameters saved.

The mark interface is used if the reader supports it.

Specified by:

restoreInput in class ForthReader

Parameters:

vm - the virtual machine to recover input parameters form.

Returns:

the ForthReader to use for further input or null if the input environment could not be recovered.

refill

public boolean refill()
               throws java.io.IOException

Description copied from class: ForthReader

Attempt to fill the input buffer from the input source, and return true if successful.

If successful, make the result the input buffer, set position to zero, set bufferSize to the number of bytes read, and return true. Receipt of a line containing no characters is considered successful. If there is no input available return false.

This method is called by the Forth function refill.

Specified by:

refill in class ForthReader

Returns:

true if a line was successfully read into the buffer.

Throws:

java.io.IOException - if there is an error when reading the line.