org.antlr.v4.runtime

Class ANTLRInputStream

java.lang.Object

org.antlr.v4.runtime.ANTLRInputStream

All Implemented Interfaces:

CharStream, IntStream

Direct Known Subclasses:

ANTLRFileStream

public class ANTLRInputStream
extends Object
implements CharStream

Vacuum all input from a Reader/InputStream and then treat it like a char[] buffer. Can also pass in a String or char[] to use.

If you need encoding, pass in stream/reader with correct encoding.

Field Summary

Fields

Modifier and Type	Field and Description
protected char[]	data The data being scanned
static int	INITIAL_BUFFER_SIZE
protected int	n How many characters are actually in the buffer
String	name What is name or source of this char stream?
protected int	p 0..n-1 index into string of next char
static int	READ_BUFFER_SIZE

Fields inherited from interface org.antlr.v4.runtime.IntStream

EOF, UNKNOWN_SOURCE_NAME

Constructor Summary

Constructors

Constructor and Description
ANTLRInputStream()
ANTLRInputStream(char[] data, int numberOfActualCharsInArray) This is the preferred constructor for strings as no data is copied
ANTLRInputStream(InputStream input)
ANTLRInputStream(InputStream input, int initialSize)
ANTLRInputStream(InputStream input, int initialSize, int readChunkSize)
ANTLRInputStream(Reader r)
ANTLRInputStream(Reader r, int initialSize)
ANTLRInputStream(Reader r, int initialSize, int readChunkSize)
ANTLRInputStream(String input) Copy data in string to a local char array

Method Summary

Methods

Modifier and Type	Method and Description
void	consume() Consumes the current symbol in the stream.
String	getSourceName() Gets the name of the underlying symbol source.
String	getText(Interval interval) This method returns the text for a range of characters within this input stream.
int	index() Return the current input symbol index 0..n where n indicates the last symbol has been read.
int	LA(int i) Gets the value of the symbol at offset i from the current position.
void	load(Reader r, int size, int readChunkSize)
int	LT(int i)
int	mark() mark/release do nothing; we have entire buffer
void	release(int marker) This method releases a marked range created by a call to mark().
void	reset() Reset the stream so that it's in the same state it was when the object was created *except* the data array is not touched.
void	seek(int index) consume() ahead until p==index; can't just set p=index as we must update line and charPositionInLine.
int	size() Returns the total number of symbols in the stream, including a single EOF symbol.
String	toString()

Methods inherited from class java.lang.Object

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

Field Detail

READ_BUFFER_SIZE

public static final int READ_BUFFER_SIZE

See Also:

Constant Field Values

INITIAL_BUFFER_SIZE

public static final int INITIAL_BUFFER_SIZE

See Also:

Constant Field Values

data

protected char[] data

The data being scanned

n

protected int n

How many characters are actually in the buffer

p

protected int p

0..n-1 index into string of next char

name

public String name

What is name or source of this char stream?

Constructor Detail

ANTLRInputStream

public ANTLRInputStream()

ANTLRInputStream

public ANTLRInputStream(String input)

Copy data in string to a local char array

ANTLRInputStream

public ANTLRInputStream(char[] data,
                int numberOfActualCharsInArray)

This is the preferred constructor for strings as no data is copied

ANTLRInputStream

public ANTLRInputStream(Reader r)
                 throws IOException

Throws:

IOException

ANTLRInputStream

public ANTLRInputStream(Reader r,
                int initialSize)
                 throws IOException

Throws:

IOException

ANTLRInputStream

public ANTLRInputStream(Reader r,
                int initialSize,
                int readChunkSize)
                 throws IOException

Throws:

IOException

ANTLRInputStream

public ANTLRInputStream(InputStream input)
                 throws IOException

Throws:

IOException

ANTLRInputStream

public ANTLRInputStream(InputStream input,
                int initialSize)
                 throws IOException

Throws:

IOException

ANTLRInputStream

public ANTLRInputStream(InputStream input,
                int initialSize,
                int readChunkSize)
                 throws IOException

Throws:

IOException

Method Detail

load

public void load(Reader r,
        int size,
        int readChunkSize)
          throws IOException

Throws:

IOException

reset

public void reset()

Reset the stream so that it's in the same state it was when the object was created *except* the data array is not touched.

consume

public void consume()

Description copied from interface: IntStream

Consumes the current symbol in the stream. This method has the following effects:

• Forward movement: The value of index() before calling this method is less than the value of index() after calling this method.
• Ordered lookahead: The value of LA(1) before calling this method becomes the value of LA(-1) after calling this method.

Note that calling this method does not guarantee that index() is incremented by exactly 1, as that would preclude the ability to implement filtering streams (e.g. CommonTokenStream which distinguishes between "on-channel" and "off-channel" tokens).

Specified by:

consume in interface IntStream

LA

public int LA(int i)

Description copied from interface: IntStream

Gets the value of the symbol at offset i from the current position. When i==1, this method returns the value of the current symbol in the stream (which is the next symbol to be consumed). When i==-1, this method returns the value of the previously read symbol in the stream. It is not valid to call this method with i==0, but the specific behavior is unspecified because this method is frequently called from performance-critical code.

This method is guaranteed to succeed if any of the following are true:

• i>0
• i==-1 and index() returns a value greater than the value of index() after the stream was constructed and LA(1) was called in that order. Specifying the current index() relative to the index after the stream was created allows for filtering implementations that do not return every symbol from the underlying source. Specifying the call to LA(1) allows for lazily initialized streams.
• LA(i) refers to a symbol consumed within a marked region that has not yet been released.

If i represents a position at or beyond the end of the stream, this method returns IntStream.EOF.

The return value is unspecified if i<0 and fewer than -i calls to consume() have occurred from the beginning of the stream before calling this method.

Specified by:

LA in interface IntStream

LT

public int LT(int i)

index

public int index()

Return the current input symbol index 0..n where n indicates the last symbol has been read. The index is the index of char to be returned from LA(1).

Specified by:

index in interface IntStream

size

public int size()

Description copied from interface: IntStream

Returns the total number of symbols in the stream, including a single EOF symbol.

Specified by:

size in interface IntStream

mark

public int mark()

mark/release do nothing; we have entire buffer

Specified by:

mark in interface IntStream

Returns:

An opaque marker which should be passed to release() when the marked range is no longer required.

release

public void release(int marker)

Description copied from interface: IntStream

This method releases a marked range created by a call to mark(). Calls to release() must appear in the reverse order of the corresponding calls to mark(). If a mark is released twice, or if marks are not released in reverse order of the corresponding calls to mark(), the behavior is unspecified.

For more information and an example, see IntStream.mark().

Specified by:

release in interface IntStream

Parameters:

marker - A marker returned by a call to mark().

See Also:

IntStream.mark()

seek

public void seek(int index)

consume() ahead until p==index; can't just set p=index as we must update line and charPositionInLine. If we seek backwards, just set p

Specified by:

seek in interface IntStream

Parameters:

index - The absolute index to seek to.

getText

public String getText(Interval interval)

Description copied from interface: CharStream

This method returns the text for a range of characters within this input stream. This method is guaranteed to not throw an exception if the specified interval lies entirely within a marked range. For more information about marked ranges, see IntStream.mark().

Specified by:

getText in interface CharStream

Parameters:

interval - an interval within the stream

Returns:

the text of the specified interval

getSourceName

public String getSourceName()

Description copied from interface: IntStream

Gets the name of the underlying symbol source. This method returns a non-null, non-empty string. If such a name is not known, this method returns IntStream.UNKNOWN_SOURCE_NAME.

Specified by:

getSourceName in interface IntStream

toString

public String toString()

Overrides:

toString in class Object