| /* |
| [The "BSD license"] |
| Copyright (c) 2005-2009 Terence Parr |
| All rights reserved. |
| |
| Redistribution and use in source and binary forms, with or without |
| modification, are permitted provided that the following conditions |
| are met: |
| 1. Redistributions of source code must retain the above copyright |
| notice, this list of conditions and the following disclaimer. |
| 2. Redistributions in binary form must reproduce the above copyright |
| notice, this list of conditions and the following disclaimer in the |
| documentation and/or other materials provided with the distribution. |
| 3. The name of the author may not be used to endorse or promote products |
| derived from this software without specific prior written permission. |
| |
| THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
| IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
| OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
| IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
| INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
| NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
| THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| package org.antlr.runtime.tree; |
| |
| import org.antlr.runtime.RecognitionException; |
| import org.antlr.runtime.Token; |
| import org.antlr.runtime.TokenStream; |
| import org.antlr.runtime.misc.LookaheadStream; |
| import org.antlr.runtime.misc.IntArray; |
| |
| public class CommonTreeNodeStream extends LookaheadStream<Object> implements TreeNodeStream, PositionTrackingStream<Object> { |
| public static final int DEFAULT_INITIAL_BUFFER_SIZE = 100; |
| public static final int INITIAL_CALL_STACK_SIZE = 10; |
| |
| /** Pull nodes from which tree? */ |
| protected Object root; |
| |
| /** If this tree (root) was created from a {@link TokenStream}, track it. */ |
| protected TokenStream tokens; |
| |
| /** What {@link TreeAdaptor} was used to build these trees */ |
| TreeAdaptor adaptor; |
| |
| /** The {@link TreeIterator} we using. */ |
| protected TreeIterator it; |
| |
| /** Stack of indexes used for push/pop calls. */ |
| protected IntArray calls; |
| |
| /** Tree {@code (nil A B C)} trees like flat {@code A B C} streams */ |
| protected boolean hasNilRoot = false; |
| |
| /** Tracks tree depth. Level=0 means we're at root node level. */ |
| protected int level = 0; |
| |
| /** |
| * Tracks the last node before the start of {@link #data} which contains |
| * position information to provide information for error reporting. This is |
| * tracked in addition to {@link #prevElement} which may or may not contain |
| * position information. |
| * |
| * @see #hasPositionInformation |
| * @see RecognitionException#extractInformationFromTreeNodeStream |
| */ |
| protected Object previousLocationElement; |
| |
| public CommonTreeNodeStream(Object tree) { |
| this(new CommonTreeAdaptor(), tree); |
| } |
| |
| public CommonTreeNodeStream(TreeAdaptor adaptor, Object tree) { |
| this.root = tree; |
| this.adaptor = adaptor; |
| it = new TreeIterator(adaptor,root); |
| } |
| |
| @Override |
| public void reset() { |
| super.reset(); |
| it.reset(); |
| hasNilRoot = false; |
| level = 0; |
| previousLocationElement = null; |
| if ( calls != null ) calls.clear(); |
| } |
| |
| /** Pull elements from tree iterator. Track tree level 0..max_level. |
| * If nil rooted tree, don't give initial nil and DOWN nor final UP. |
| */ |
| @Override |
| public Object nextElement() { |
| Object t = it.next(); |
| //System.out.println("pulled "+adaptor.getType(t)); |
| if ( t == it.up ) { |
| level--; |
| if ( level==0 && hasNilRoot ) return it.next(); // don't give last UP; get EOF |
| } |
| else if ( t == it.down ) level++; |
| if ( level==0 && adaptor.isNil(t) ) { // if nil root, scarf nil, DOWN |
| hasNilRoot = true; |
| t = it.next(); // t is now DOWN, so get first real node next |
| level++; |
| t = it.next(); |
| } |
| return t; |
| } |
| |
| @Override |
| public Object remove() { |
| Object result = super.remove(); |
| if (p == 0 && hasPositionInformation(prevElement)) { |
| previousLocationElement = prevElement; |
| } |
| |
| return result; |
| } |
| |
| @Override |
| public boolean isEOF(Object o) { return adaptor.getType(o) == Token.EOF; } |
| |
| @Override |
| public void setUniqueNavigationNodes(boolean uniqueNavigationNodes) { } |
| |
| @Override |
| public Object getTreeSource() { return root; } |
| |
| @Override |
| public String getSourceName() { return getTokenStream().getSourceName(); } |
| |
| @Override |
| public TokenStream getTokenStream() { return tokens; } |
| |
| public void setTokenStream(TokenStream tokens) { this.tokens = tokens; } |
| |
| @Override |
| public TreeAdaptor getTreeAdaptor() { return adaptor; } |
| |
| public void setTreeAdaptor(TreeAdaptor adaptor) { this.adaptor = adaptor; } |
| |
| @Override |
| public Object get(int i) { |
| throw new UnsupportedOperationException("Absolute node indexes are meaningless in an unbuffered stream"); |
| } |
| |
| @Override |
| public int LA(int i) { return adaptor.getType(LT(i)); } |
| |
| /** Make stream jump to a new location, saving old location. |
| * Switch back with pop(). |
| */ |
| public void push(int index) { |
| if ( calls==null ) { |
| calls = new IntArray(); |
| } |
| calls.push(p); // save current index |
| seek(index); |
| } |
| |
| /** Seek back to previous index saved during last {@link #push} call. |
| * Return top of stack (return index). |
| */ |
| public int pop() { |
| int ret = calls.pop(); |
| seek(ret); |
| return ret; |
| } |
| |
| /** |
| * Returns an element containing position information. If {@code allowApproximateLocation} is {@code false}, then |
| * this method will return the {@code LT(1)} element if it contains position information, and otherwise return {@code null}. |
| * If {@code allowApproximateLocation} is {@code true}, then this method will return the last known element containing position information. |
| * |
| * @see #hasPositionInformation |
| */ |
| @Override |
| public Object getKnownPositionElement(boolean allowApproximateLocation) { |
| Object node = data.get(p); |
| if (hasPositionInformation(node)) { |
| return node; |
| } |
| |
| if (!allowApproximateLocation) { |
| return null; |
| } |
| |
| for (int index = p - 1; index >= 0; index--) { |
| node = data.get(index); |
| if (hasPositionInformation(node)) { |
| return node; |
| } |
| } |
| |
| return previousLocationElement; |
| } |
| |
| @Override |
| public boolean hasPositionInformation(Object node) { |
| Token token = adaptor.getToken(node); |
| if (token == null) { |
| return false; |
| } |
| |
| if (token.getLine() <= 0) { |
| return false; |
| } |
| |
| return true; |
| } |
| |
| // TREE REWRITE INTERFACE |
| |
| @Override |
| public void replaceChildren(Object parent, int startChildIndex, int stopChildIndex, Object t) { |
| if ( parent!=null ) { |
| adaptor.replaceChildren(parent, startChildIndex, stopChildIndex, t); |
| } |
| } |
| |
| @Override |
| public String toString(Object start, Object stop) { |
| // we'll have to walk from start to stop in tree; we're not keeping |
| // a complete node stream buffer |
| return "n/a"; |
| } |
| |
| /** For debugging; destructive: moves tree iterator to end. */ |
| public String toTokenTypeString() { |
| reset(); |
| StringBuilder buf = new StringBuilder(); |
| Object o = LT(1); |
| int type = adaptor.getType(o); |
| while ( type!=Token.EOF ) { |
| buf.append(" "); |
| buf.append(type); |
| consume(); |
| o = LT(1); |
| type = adaptor.getType(o); |
| } |
| return buf.toString(); |
| } |
| } |