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UnbufferedTokenStream (ANTLR 4 Runtime (Optimized) 4.7.3 API)
org.antlr.v4.runtime
Class UnbufferedTokenStream
- java.lang.Object
-
- org.antlr.v4.runtime.UnbufferedTokenStream
-
- All Implemented Interfaces:
- IntStream, TokenStream
public class UnbufferedTokenStream
extends Object
implements TokenStream
-
-
Field Summary
Fields
Modifier and Type
Field and Description
protected int
currentTokenIndex
Absolute token index.
protected Token
lastToken
This is the LT(-1)
token for the current position.
protected Token
lastTokenBufferStart
protected int
n
The number of tokens currently in tokens
.
protected int
numMarkers
protected int
p
0..n-1 index into tokens
of next token.
protected Token[]
tokens
A moving window buffer of the data being scanned.
protected TokenSource
tokenSource
-
Fields inherited from interface org.antlr.v4.runtime.IntStream
EOF, UNKNOWN_SOURCE_NAME
-
Constructor Summary
Constructors
Constructor and Description
UnbufferedTokenStream(TokenSource tokenSource)
UnbufferedTokenStream(TokenSource tokenSource,
int bufferSize)
-
Method Summary
Methods
Modifier and Type
Method and Description
protected void
add(Token t)
void
consume()
Consumes the current symbol in the stream.
protected int
fill(int n)
Add n
elements to the buffer.
Token
get(int i)
Gets the Token
at the specified index
in the stream.
protected int
getBufferStartIndex()
String
getSourceName()
Gets the name of the underlying symbol source.
String
getText()
Return the text of all tokens in the stream.
String
getText(Interval interval)
Return the text of all tokens within the specified interval
.
String
getText(Object start,
Object stop)
Return the text of all tokens in this stream between start
and
stop
(inclusive).
String
getText(RuleContext ctx)
Return the text of all tokens in the source interval of the specified
context.
TokenSource
getTokenSource()
Gets the underlying TokenSource
which provides tokens for this
stream.
int
index()
Return the index into the stream of the input symbol referred to by
LA(1)
.
int
LA(int i)
Gets the value of the symbol at offset i
from the current
position.
Token
LT(int i)
int
mark()
Return a marker that we can release later.
void
release(int marker)
This method releases a marked range created by a call to
mark()
.
void
seek(int index)
Set the input cursor to the position indicated by index
.
int
size()
Returns the total number of symbols in the stream, including a single EOF
symbol.
protected void
sync(int want)
Make sure we have 'need' elements from current position p
.
-
-
Field Detail
-
tokenSource
protected TokenSource tokenSource
-
tokens
protected Token[] tokens
A moving window buffer of the data being scanned. While there's a marker,
we keep adding to buffer. Otherwise, consume()
resets so
we start filling at index 0 again.
-
n
protected int n
The number of tokens currently in tokens
.
This is not the buffer capacity, that's tokens.length
.
-
p
protected int p
0..n-1 index into tokens
of next token.
The LT(1)
token is tokens[p]
. If p == n
, we are
out of buffered tokens.
-
numMarkers
protected int numMarkers
-
lastToken
protected Token lastToken
This is the LT(-1)
token for the current position.
-
lastTokenBufferStart
protected Token lastTokenBufferStart
When numMarkers > 0
, this is the LT(-1)
token for the
first token in tokens
. Otherwise, this is null
.
-
currentTokenIndex
protected int currentTokenIndex
Absolute token index. It's the index of the token about to be read via
LT(1)
. Goes from 0 to the number of tokens in the entire stream,
although the stream size is unknown before the end is reached.
This value is used to set the token indexes if the stream provides tokens
that implement WritableToken
.
-
Constructor Detail
-
UnbufferedTokenStream
public UnbufferedTokenStream(TokenSource tokenSource)
-
UnbufferedTokenStream
public UnbufferedTokenStream(TokenSource tokenSource,
int bufferSize)
-
Method Detail
-
get
public Token get(int i)
Description copied from interface: TokenStream
Gets the Token
at the specified index
in the stream. When
the preconditions of this method are met, the return value is non-null.
The preconditions for this method are the same as the preconditions of
IntStream.seek(int)
. If the behavior of seek(index)
is
unspecified for the current state and given index
, then the
behavior of this method is also unspecified.
The symbol referred to by index
differs from seek()
only
in the case of filtering streams where index
lies before the end
of the stream. Unlike seek()
, this method does not adjust
index
to point to a non-ignored symbol.
- Specified by:
get
in interface TokenStream
-
LT
public Token LT(int i)
Description copied from interface: TokenStream
Get the Token
instance associated with the value returned by
LA(k)
. This method has the same pre- and post-conditions as
IntStream.LA(int)
. In addition, when the preconditions of this method
are met, the return value is non-null and the value of
LT(k).getType()==LA(k)
.
- Specified by:
LT
in interface TokenStream
- See Also:
IntStream.LA(int)
-
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.
-
getTokenSource
public TokenSource getTokenSource()
Description copied from interface: TokenStream
Gets the underlying TokenSource
which provides tokens for this
stream.
- Specified by:
getTokenSource
in interface TokenStream
-
getText
@NotNull
public String getText()
Description copied from interface: TokenStream
Return the text of all tokens in the stream. This method behaves like the
following code, including potential exceptions from the calls to
IntStream.size()
and TokenStream.getText(Interval)
, but may be
optimized by the specific implementation.
TokenStream stream = ...;
String text = stream.getText(new Interval(0, stream.size()));
- Specified by:
getText
in interface TokenStream
- Returns:
- The text of all tokens in the stream.
-
getText
@NotNull
public String getText(RuleContext ctx)
Description copied from interface: TokenStream
Return the text of all tokens in the source interval of the specified
context. This method behaves like the following code, including potential
exceptions from the call to TokenStream.getText(Interval)
, but may be
optimized by the specific implementation.
If ctx.getSourceInterval()
does not return a valid interval of
tokens provided by this stream, the behavior is unspecified.
TokenStream stream = ...;
String text = stream.getText(ctx.getSourceInterval());
- Specified by:
getText
in interface TokenStream
- Parameters:
ctx
- The context providing the source interval of tokens to get
text for.
- Returns:
- The text of all tokens within the source interval of
ctx
.
-
getText
@NotNull
public String getText(Object start,
Object stop)
Description copied from interface: TokenStream
Return the text of all tokens in this stream between start
and
stop
(inclusive).
If the specified start
or stop
token was not provided by
this stream, or if the stop
occurred before the start
token, the behavior is unspecified.
For streams which ensure that the Token.getTokenIndex()
method is
accurate for all of its provided tokens, this method behaves like the
following code. Other streams may implement this method in other ways
provided the behavior is consistent with this at a high level.
TokenStream stream = ...;
String text = "";
for (int i = start.getTokenIndex(); i <= stop.getTokenIndex(); i++) {
text += stream.get(i).getText();
}
- Specified by:
getText
in interface TokenStream
- Parameters:
start
- The first token in the interval to get text for.stop
- The last token in the interval to get text for (inclusive).
- Returns:
- The text of all tokens lying between the specified
start
and stop
tokens.
-
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).
-
sync
protected void sync(int want)
Make sure we have 'need' elements from current position p
. Last valid
p
index is tokens.length-1
. p+need-1
is the tokens index 'need' elements
ahead. If we need 1 element, (p+1-1)==p
must be less than tokens.length
.
-
fill
protected int fill(int n)
Add n
elements to the buffer. Returns the number of tokens
actually added to the buffer. If the return value is less than n
,
then EOF was reached before n
tokens could be added.
-
add
protected void add(@NotNull
Token t)
-
mark
public int mark()
Return a marker that we can release later.
The specific marker value used for this class allows for some level of
protection against misuse where seek()
is called on a mark or
release()
is called in the wrong order.
-
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()
-
index
public int index()
Description copied from interface: IntStream
Return the index into the stream of the input symbol referred to by
LA(1)
.
The behavior of this method is unspecified if no call to an
initializing method
has occurred after this stream was
constructed.
-
seek
public void seek(int index)
Description copied from interface: IntStream
Set the input cursor to the position indicated by index
. If the
specified index lies past the end of the stream, the operation behaves as
though index
was the index of the EOF symbol. After this method
returns without throwing an exception, then at least one of the following
will be true.
index()
will return the index of the first symbol
appearing at or after the specified index
. Specifically,
implementations which filter their sources should automatically
adjust index
forward the minimum amount required for the
operation to target a non-ignored symbol.
LA(1)
returns IntStream.EOF
This operation is guaranteed to not throw an exception if index
lies within a marked region. For more information on marked regions, see
IntStream.mark()
. The behavior of this method is unspecified if no call to
an initializing method
has occurred after this stream
was constructed.
-
size
public int size()
Description copied from interface: IntStream
Returns the total number of symbols in the stream, including a single EOF
symbol.
-
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
-
getText
@NotNull
public String getText(Interval interval)
Description copied from interface: TokenStream
Return the text of all tokens within the specified interval
. This
method behaves like the following code (including potential exceptions
for violating preconditions of TokenStream.get(int)
, but may be optimized by the
specific implementation.
TokenStream stream = ...;
String text = "";
for (int i = interval.a; i <= interval.b; i++) {
text += stream.get(i).getText();
}
- Specified by:
getText
in interface TokenStream
- Parameters:
interval
- The interval of tokens within this stream to get text
for.
- Returns:
- The text of all tokens within the specified interval in this
stream.
-
getBufferStartIndex
protected final int getBufferStartIndex()
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