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IntStream (ANTLR 4 Runtime (Optimized) 4.7.3 API)













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org.antlr.v4.runtime
Interface IntStream






All Known Subinterfaces:
CharStream, TokenStream, UnicodeCharStream


All Known Implementing Classes:
ANTLRFileStream, ANTLRInputStream, BufferedTokenStream, CodePointCharStream, CommonTokenStream, UnbufferedCharStream, UnbufferedTokenStream




public interface IntStream
A simple stream of symbols whose values are represented as integers. This
 interface provides marked ranges with support for a minimum level
 of buffering necessary to implement arbitrary lookahead during prediction.
 For more information on marked ranges, see mark().

 Initializing Methods: Some methods in this interface have
 unspecified behavior if no call to an initializing method has occurred after
 the stream was constructed. The following is a list of initializing methods:

 
   LA(int)
   consume()
   size()
 











Field Summary

Fields 

Modifier and Type
Field and Description


static int
EOF
The value returned by LA() when the end of the stream is
 reached.



static String
UNKNOWN_SOURCE_NAME
The value returned by getSourceName() when the actual name of the
 underlying source is not known.










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.



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.



int
mark()
A mark provides a guarantee that seek() operations will be
 valid over a "marked range" extending from the index where mark()
 was called to the current index().



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.
















Field Detail





EOF
static final int EOF
The value returned by LA() when the end of the stream is
 reached.
See Also:
Constant Field Values







UNKNOWN_SOURCE_NAME
static final String UNKNOWN_SOURCE_NAME
The value returned by getSourceName() when the actual name of the
 underlying source is not known.
See Also:
Constant Field Values









Method Detail





consume
void consume()
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).
Throws:
IllegalStateException - if an attempt is made to consume the
 end of the stream (i.e. if LA(1)==EOF before calling
 consume).







LA
int LA(int i)
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 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.
Throws:
UnsupportedOperationException - if the stream does not support
 retrieving the value of the specified symbol







mark
int mark()
A mark provides a guarantee that seek() operations will be
 valid over a "marked range" extending from the index where mark()
 was called to the current index(). This allows the use of
 streaming input sources by specifying the minimum buffering requirements
 to support arbitrary lookahead during prediction.

 The returned mark is an opaque handle (type int) which is passed
 to release() when the guarantees provided by the marked
 range are no longer necessary. When calls to
 mark()/release() are nested, the marks must be released
 in reverse order of which they were obtained. Since marked regions are
 used during performance-critical sections of prediction, the specific
 behavior of invalid usage is unspecified (i.e. a mark is not released, or
 a mark is released twice, or marks are not released in reverse order from
 which they were created).

 The behavior of this method is unspecified if no call to an
 initializing method has occurred after this stream was
 constructed.

 This method does not change the current position in the input stream.

 The following example shows the use of mark(),
 release(mark), index(), and
 seek(index) as part of an operation to safely work within a
 marked region, then restore the stream position to its original value and
 release the mark.
  IntStream stream = ...;
 int index = -1;
 int mark = stream.mark();
 try {
   index = stream.index();
   // perform work here...
 } finally {
   if (index != -1) {
     stream.seek(index);
   }
   stream.release(mark);
 }
 
Returns:
An opaque marker which should be passed to
 release() when the marked range is no longer required.







release
void release(int marker)
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 mark().
Parameters:
marker - A marker returned by a call to mark().
See Also:
mark()







index
int index()
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
void seek(int index)
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 EOF
 

 This operation is guaranteed to not throw an exception if index
 lies within a marked region. For more information on marked regions, see
 mark(). The behavior of this method is unspecified if no call to
 an initializing method has occurred after this stream
 was constructed.
Parameters:
index - The absolute index to seek to.
Throws:
IllegalArgumentException - if index is less than 0
UnsupportedOperationException - if the stream does not support
 seeking to the specified index







size
int size()
Returns the total number of symbols in the stream, including a single EOF
 symbol.
Throws:
UnsupportedOperationException - if the size of the stream is
 unknown.







getSourceName
@NotNull
String getSourceName()
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 UNKNOWN_SOURCE_NAME.
















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Copyright © 1992–2019 Tunnel Vision Laboratories, LLC. All rights reserved.

Modifier and Type	Field and Description
`static int`	`EOF` The value returned by `LA()` when the end of the stream is reached.
`static String`	`UNKNOWN_SOURCE_NAME` The value returned by `getSourceName()` when the actual name of the underlying source is not known.

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.
`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.
`int`	`mark()` A mark provides a guarantee that `seek()` operations will be valid over a "marked range" extending from the index where `mark()` was called to the current `index()`.
`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.