/Users/parrt/antlr/code/antlr/main/runtime/Java/src/org/antlr/runtime/TokenRewriteStream.java

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/*
 [The "BSD licence"]
 Copyright (c) 2005-2008 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;

import java.util.*;

public class TokenRewriteStream extends CommonTokenStream {
        public static final String DEFAULT_PROGRAM_NAME = "default";
    public static final int PROGRAM_INIT_SIZE = 100;
        public static final int MIN_TOKEN_INDEX = 0;

        // Define the rewrite operation hierarchy

        class RewriteOperation {
        protected int instructionIndex;
        protected int index;
                protected Object text;
                protected RewriteOperation(int index, Object text) {
                        this.index = index;
                        this.text = text;
                }
                public int execute(StringBuffer buf) {
                        return index;
                }
                public String toString() {
                        String opName = getClass().getName();
                        int $index = opName.indexOf('$');
                        opName = opName.substring($index+1, opName.length());
                        return "<"+opName+"@"+index+":\""+text+"\">";                   
                }
        }

        class InsertBeforeOp extends RewriteOperation {
                public InsertBeforeOp(int index, Object text) {
                        super(index,text);
                }
                public int execute(StringBuffer buf) {
                        buf.append(text);
                        buf.append(((Token)tokens.get(index)).getText());                       
                        return index+1;
                }
        }

        class ReplaceOp extends RewriteOperation {
                protected int lastIndex;
                public ReplaceOp(int from, int to, Object text) {
                        super(from,text);
                        lastIndex = to;
                }
                public int execute(StringBuffer buf) {
                        if ( text!=null ) {
                                buf.append(text);
                        }
                        return lastIndex+1;
                }
                public String toString() {
                        return "<ReplaceOp@"+index+".."+lastIndex+":\""+text+"\">";
                }
        }

        class DeleteOp extends ReplaceOp {
                public DeleteOp(int from, int to) {
                        super(from, to, null);
                }
                public String toString() {
                        return "<DeleteOp@"+index+".."+lastIndex+">";
                }
        }

        protected Map programs = null;

        protected Map lastRewriteTokenIndexes = null;

        public TokenRewriteStream() {
                init();
        }

        protected void init() {
                programs = new HashMap();
                programs.put(DEFAULT_PROGRAM_NAME, new ArrayList(PROGRAM_INIT_SIZE));
                lastRewriteTokenIndexes = new HashMap();
        }

        public TokenRewriteStream(TokenSource tokenSource) {
            super(tokenSource);
                init();
        }

        public TokenRewriteStream(TokenSource tokenSource, int channel) {
                super(tokenSource, channel);
                init();
        }

        public void rollback(int instructionIndex) {
                rollback(DEFAULT_PROGRAM_NAME, instructionIndex);
        }

        public void rollback(String programName, int instructionIndex) {
                List is = (List)programs.get(programName);
                if ( is!=null ) {
                        programs.put(programName, is.subList(MIN_TOKEN_INDEX,instructionIndex));
                }
        }

        public void deleteProgram() {
                deleteProgram(DEFAULT_PROGRAM_NAME);
        }

        public void deleteProgram(String programName) {
                rollback(programName, MIN_TOKEN_INDEX);
        }

        public void insertAfter(Token t, Object text) {
                insertAfter(DEFAULT_PROGRAM_NAME, t, text);
        }

        public void insertAfter(int index, Object text) {
                insertAfter(DEFAULT_PROGRAM_NAME, index, text);
        }

        public void insertAfter(String programName, Token t, Object text) {
                insertAfter(programName,t.getTokenIndex(), text);
        }

        public void insertAfter(String programName, int index, Object text) {
                // to insert after, just insert before next index (even if past end)
                insertBefore(programName,index+1, text);
                //addToSortedRewriteList(programName, new InsertAfterOp(index,text));
        }

        public void insertBefore(Token t, Object text) {
                insertBefore(DEFAULT_PROGRAM_NAME, t, text);
        }

        public void insertBefore(int index, Object text) {
                insertBefore(DEFAULT_PROGRAM_NAME, index, text);
        }

        public void insertBefore(String programName, Token t, Object text) {
                insertBefore(programName, t.getTokenIndex(), text);
        }

        public void insertBefore(String programName, int index, Object text) {
                //addToSortedRewriteList(programName, new InsertBeforeOp(index,text));
                RewriteOperation op = new InsertBeforeOp(index,text);
                List rewrites = getProgram(programName);
        op.instructionIndex = rewrites.size();
        rewrites.add(op);               
        }

        public void replace(int index, Object text) {
                replace(DEFAULT_PROGRAM_NAME, index, index, text);
        }

        public void replace(int from, int to, Object text) {
                replace(DEFAULT_PROGRAM_NAME, from, to, text);
        }

        public void replace(Token indexT, Object text) {
                replace(DEFAULT_PROGRAM_NAME, indexT, indexT, text);
        }

        public void replace(Token from, Token to, Object text) {
                replace(DEFAULT_PROGRAM_NAME, from, to, text);
        }

        public void replace(String programName, int from, int to, Object text) {
                if ( from > to || from<0 || to<0 || to >= tokens.size() ) {
                        throw new IllegalArgumentException("replace: range invalid: "+from+".."+to+"(size="+tokens.size()+")");
                }
                RewriteOperation op = new ReplaceOp(from, to, text);
                List rewrites = getProgram(programName);
        op.instructionIndex = rewrites.size();
        rewrites.add(op);
        }

        public void replace(String programName, Token from, Token to, Object text) {
                replace(programName,
                                from.getTokenIndex(),
                                to.getTokenIndex(),
                                text);
        }

        public void delete(int index) {
                delete(DEFAULT_PROGRAM_NAME, index, index);
        }

        public void delete(int from, int to) {
                delete(DEFAULT_PROGRAM_NAME, from, to);
        }

        public void delete(Token indexT) {
                delete(DEFAULT_PROGRAM_NAME, indexT, indexT);
        }

        public void delete(Token from, Token to) {
                delete(DEFAULT_PROGRAM_NAME, from, to);
        }

        public void delete(String programName, int from, int to) {
                replace(programName,from,to,null);
        }

        public void delete(String programName, Token from, Token to) {
                replace(programName,from,to,null);
        }

        public int getLastRewriteTokenIndex() {
                return getLastRewriteTokenIndex(DEFAULT_PROGRAM_NAME);
        }

        protected int getLastRewriteTokenIndex(String programName) {
                Integer I = (Integer)lastRewriteTokenIndexes.get(programName);
                if ( I==null ) {
                        return -1;
                }
                return I.intValue();
        }

        protected void setLastRewriteTokenIndex(String programName, int i) {
                lastRewriteTokenIndexes.put(programName, new Integer(i));
        }

        protected List getProgram(String name) {
                List is = (List)programs.get(name);
                if ( is==null ) {
                        is = initializeProgram(name);
                }
                return is;
        }

        private List initializeProgram(String name) {
                List is = new ArrayList(PROGRAM_INIT_SIZE);
                programs.put(name, is);
                return is;
        }

        public String toOriginalString() {
                return toOriginalString(MIN_TOKEN_INDEX, size()-1);
        }

        public String toOriginalString(int start, int end) {
                StringBuffer buf = new StringBuffer();
                for (int i=start; i>=MIN_TOKEN_INDEX && i<=end && i<tokens.size(); i++) {
                        buf.append(get(i).getText());
                }
                return buf.toString();
        }

        public String toString() {
                return toString(MIN_TOKEN_INDEX, size()-1);
        }

        public String toString(String programName) {
                return toString(programName, MIN_TOKEN_INDEX, size()-1);
        }

        public String toString(int start, int end) {
                return toString(DEFAULT_PROGRAM_NAME, start, end);
        }

        public String toString(String programName, int start, int end) {
                List rewrites = (List)programs.get(programName);

        // ensure start/end are in range
        if ( end>tokens.size()-1 ) end = tokens.size()-1;
        if ( start<0 ) start = 0;

        if ( rewrites==null || rewrites.size()==0 ) {
                        return toOriginalString(start,end); // no instructions to execute
                }
                StringBuffer buf = new StringBuffer();

                // First, optimize instruction stream
                Map indexToOp = reduceToSingleOperationPerIndex(rewrites);

        // Walk buffer, executing instructions and emitting tokens
        int i = start;
        while ( i <= end && i < tokens.size() ) {
                        RewriteOperation op = (RewriteOperation)indexToOp.get(new Integer(i));
                        indexToOp.remove(new Integer(i)); // remove so any left have index size-1
                        Token t = (Token) tokens.get(i);
                        if ( op==null ) {
                                // no operation at that index, just dump token
                                buf.append(t.getText());
                                i++; // move to next token
                        }
                        else {
                                i = op.execute(buf); // execute operation and skip
                        }
                }

        // include stuff after end if it's last index in buffer
        // So, if they did an insertAfter(lastValidIndex, "foo"), include
        // foo if end==lastValidIndex.
        if ( end==tokens.size()-1 ) {
            // Scan any remaining operations after last token
            // should be included (they will be inserts).
            Iterator it = indexToOp.values().iterator();
            while (it.hasNext()) {
                RewriteOperation op = (RewriteOperation)it.next();
                if ( op.index >= tokens.size()-1 ) buf.append(op.text);
            }
        }
        return buf.toString();
        }

        protected Map reduceToSingleOperationPerIndex(List rewrites) {
                //System.out.println("rewrites="+rewrites);

                // WALK REPLACES
                for (int i = 0; i < rewrites.size(); i++) {
                        RewriteOperation op = (RewriteOperation)rewrites.get(i);
                        if ( op==null ) continue;
                        if ( !(op instanceof ReplaceOp) ) continue;
                        ReplaceOp rop = (ReplaceOp)rewrites.get(i);
                        // Wipe prior inserts within range
                        List inserts = getKindOfOps(rewrites, InsertBeforeOp.class, i);
                        for (int j = 0; j < inserts.size(); j++) {
                                InsertBeforeOp iop = (InsertBeforeOp) inserts.get(j);
                                if ( iop.index >= rop.index && iop.index <= rop.lastIndex ) {
                    // delete insert as it's a no-op.
                    rewrites.set(iop.instructionIndex, null);
                                }
                        }
                        // Drop any prior replaces contained within
                        List prevReplaces = getKindOfOps(rewrites, ReplaceOp.class, i);
                        for (int j = 0; j < prevReplaces.size(); j++) {
                                ReplaceOp prevRop = (ReplaceOp) prevReplaces.get(j);
                                if ( prevRop.index>=rop.index && prevRop.lastIndex <= rop.lastIndex ) {
                    // delete replace as it's a no-op.
                    rewrites.set(prevRop.instructionIndex, null);
                                        continue;
                                }
                                // throw exception unless disjoint or identical
                                boolean disjoint =
                                        prevRop.lastIndex<rop.index || prevRop.index > rop.lastIndex;
                                boolean same =
                                        prevRop.index==rop.index && prevRop.lastIndex==rop.lastIndex;
                                if ( !disjoint && !same ) {
                                        throw new IllegalArgumentException("replace op boundaries of "+rop+
                                                                                                           " overlap with previous "+prevRop);
                                }
                        }
                }

                // WALK INSERTS
                for (int i = 0; i < rewrites.size(); i++) {
                        RewriteOperation op = (RewriteOperation)rewrites.get(i);
                        if ( op==null ) continue;
                        if ( !(op instanceof InsertBeforeOp) ) continue;
                        InsertBeforeOp iop = (InsertBeforeOp)rewrites.get(i);
                        // combine current insert with prior if any at same index
                        List prevInserts = getKindOfOps(rewrites, InsertBeforeOp.class, i);
                        for (int j = 0; j < prevInserts.size(); j++) {
                                InsertBeforeOp prevIop = (InsertBeforeOp) prevInserts.get(j);
                                if ( prevIop.index == iop.index ) { // combine objects
                                        // convert to strings...we're in process of toString'ing
                                        // whole token buffer so no lazy eval issue with any templates
                                        iop.text = catOpText(iop.text,prevIop.text);
                    // delete redundant prior insert
                    rewrites.set(prevIop.instructionIndex, null);
                                }
                        }
                        // look for replaces where iop.index is in range; error
                        List prevReplaces = getKindOfOps(rewrites, ReplaceOp.class, i);
                        for (int j = 0; j < prevReplaces.size(); j++) {
                                ReplaceOp rop = (ReplaceOp) prevReplaces.get(j);
                                if ( iop.index == rop.index ) {
                                        rop.text = catOpText(iop.text,rop.text);
                                        rewrites.set(i, null);  // delete current insert
                                        continue;
                                }
                                if ( iop.index >= rop.index && iop.index <= rop.lastIndex ) {
                                        throw new IllegalArgumentException("insert op "+iop+
                                                                                                           " within boundaries of previous "+rop);
                                }
                        }
                }
                // System.out.println("rewrites after="+rewrites);
                Map m = new HashMap();
                for (int i = 0; i < rewrites.size(); i++) {
                        RewriteOperation op = (RewriteOperation)rewrites.get(i);
                        if ( op==null ) continue; // ignore deleted ops
                        if ( m.get(new Integer(op.index))!=null ) {
                                throw new Error("should only be one op per index");
                        }
                        m.put(new Integer(op.index), op);
                }
                //System.out.println("index to op: "+m);
                return m;
        }

        protected String catOpText(Object a, Object b) {
                String x = "";
                String y = "";
                if ( a!=null ) x = a.toString();
                if ( b!=null ) y = b.toString();
                return x+y;
        }
        protected List getKindOfOps(List rewrites, Class kind) {
                return getKindOfOps(rewrites, kind, rewrites.size());
        }

    protected List getKindOfOps(List rewrites, Class kind, int before) {
                List ops = new ArrayList();
                for (int i=0; i<before && i<rewrites.size(); i++) {
                        RewriteOperation op = (RewriteOperation)rewrites.get(i);
                        if ( op==null ) continue; // ignore deleted
                        if ( op.getClass() == kind ) ops.add(op);
                }               
                return ops;
        }

        public String toDebugString() {
                return toDebugString(MIN_TOKEN_INDEX, size()-1);
        }

        public String toDebugString(int start, int end) {
                StringBuffer buf = new StringBuffer();
                for (int i=start; i>=MIN_TOKEN_INDEX && i<=end && i<tokens.size(); i++) {
                        buf.append(get(i));
                }
                return buf.toString();
        }
}

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