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package persistence.antlr;
/* ANTLR Translator Generator
* Project led by Terence Parr at http://www.jGuru.com
* Software rights: http://www.antlr.org/license.html
*/
import persistence.antlr.collections.impl.BitSet;
import java.util.*;
/** This token stream tracks the *entire* token stream coming from
* a lexer, but does not pass on the whitespace (or whatever else
* you want to discard) to the parser.
*
* This class can then be asked for the ith token in the input stream.
* Useful for dumping out the input stream exactly after doing some
* augmentation or other manipulations. Tokens are index from 0..n-1
*
* You can insert stuff, replace, and delete chunks. Note that the
* operations are done lazily--only if you convert the buffer to a
* String. This is very efficient because you are not moving data around
* all the time. As the buffer of tokens is converted to strings, the
* toString() method(s) check to see if there is an operation at the
* current index. If so, the operation is done and then normal String
* rendering continues on the buffer. This is like having multiple Turing
* machine instruction streams (programs) operating on a single input tape. :)
*
* Since the operations are done lazily at toString-time, operations do not
* screw up the token index values. That is, an insert operation at token
* index i does not change the index values for tokens i+1..n-1.
*
* Because operations never actually alter the buffer, you may always get
* the original token stream back without undoing anything. Since
* the instructions are queued up, you can easily simulate transactions and
* roll back any changes if there is an error just by removing instructions.
* For example,
*
* TokenStreamRewriteEngine rewriteEngine =
* new TokenStreamRewriteEngine(lexer);
* JavaRecognizer parser = new JavaRecognizer(rewriteEngine);
* ...
* rewriteEngine.insertAfter("pass1", t, "foobar");}
* rewriteEngine.insertAfter("pass2", u, "start");}
* System.out.println(rewriteEngine.toString("pass1"));
* System.out.println(rewriteEngine.toString("pass2"));
*
* You can also have multiple "instruction streams" and get multiple
* rewrites from a single pass over the input. Just name the instruction
* streams and use that name again when printing the buffer. This could be
* useful for generating a C file and also its header file--all from the
* same buffer.
*
* If you don't use named rewrite streams, a "default" stream is used.
*
* Terence Parr, [email protected]
* University of San Francisco
* February 2004
*/
public class TokenStreamRewriteEngine implements TokenStream {
public static final int MIN_TOKEN_INDEX = 0;
static class RewriteOperation {
protected int index;
protected String text;
protected RewriteOperation(int index, String text) {
this.index = index;
this.text = text;
}
/** Execute the rewrite operation by possibly adding to the buffer.
* Return the index of the next token to operate on.
*/
public int execute(StringBuffer buf) {
return index;
}
}
static class InsertBeforeOp extends RewriteOperation {
public InsertBeforeOp(int index, String text) {
super(index,text);
}
public int execute(StringBuffer buf) {
buf.append(text);
return index;
}
}
static class ReplaceOp extends RewriteOperation {
protected int lastIndex;
public ReplaceOp(int from, int to, String text) {
super(from,text);
lastIndex = to;
}
public int execute(StringBuffer buf) {
if ( text!=null ) {
buf.append(text);
}
return lastIndex+1;
}
}
static class DeleteOp extends ReplaceOp {
public DeleteOp(int from, int to) {
super(from, to, null);
}
}
public static final String DEFAULT_PROGRAM_NAME = "default";
public static final int PROGRAM_INIT_SIZE = 100;
/** Track the incoming list of tokens */
protected List tokens;
/** You may have multiple, named streams of rewrite operations.
* I'm calling these things "programs."
* Maps String (name) -> rewrite (List)
*/
protected Map programs = null;
/** Map String (program name) -> Integer index */
protected Map lastRewriteTokenIndexes = null;
/** track index of tokens */
protected int index = MIN_TOKEN_INDEX;
/** Who do we suck tokens from? */
protected TokenStream stream;
/** Which (whitespace) token(s) to throw out */
protected BitSet discardMask = new BitSet();
public TokenStreamRewriteEngine(TokenStream upstream) {
this(upstream,1000);
}
public TokenStreamRewriteEngine(TokenStream upstream, int initialSize) {
stream = upstream;
tokens = new ArrayList(initialSize);
programs = new HashMap();
programs.put(DEFAULT_PROGRAM_NAME,
new ArrayList(PROGRAM_INIT_SIZE));
lastRewriteTokenIndexes = new HashMap();
}
public Token nextToken() throws TokenStreamException {
TokenWithIndex t;
// suck tokens until end of stream or we find a non-discarded token
do {
t = (TokenWithIndex)stream.nextToken();
if ( t!=null ) {
t.setIndex(index); // what is t's index in list?
if ( t.getType()!=Token.EOF_TYPE ) {
tokens.add(t); // track all tokens except EOF
}
index++; // move to next position
}
} while ( t!=null && discardMask.member(t.getType()) );
return t;
}
public void rollback(int instructionIndex) {
rollback(DEFAULT_PROGRAM_NAME, instructionIndex);
}
/** Rollback the instruction stream for a program so that
* the indicated instruction (via instructionIndex) is no
* longer in the stream. UNTESTED!
*/
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);
}
/** Reset the program so that no instructions exist */
public void deleteProgram(String programName) {
rollback(programName, MIN_TOKEN_INDEX);
}
/** If op.index > lastRewriteTokenIndexes, just add to the end.
* Otherwise, do linear */
protected void addToSortedRewriteList(RewriteOperation op) {
addToSortedRewriteList(DEFAULT_PROGRAM_NAME, op);
}
protected void addToSortedRewriteList(String programName, RewriteOperation op) {
List rewrites = getProgram(programName);
// if at or beyond last op's index, just append
if ( op.index>=getLastRewriteTokenIndex(programName) ) {
rewrites.add(op); // append to list of operations
// record the index of this operation for next time through
setLastRewriteTokenIndex(programName, op.index);
return;
}
// not after the last one, so must insert to ordered list
Comparator comparator = new Comparator() {
public int compare(Object o, Object o1) {
RewriteOperation a = (RewriteOperation)o;
RewriteOperation b = (RewriteOperation)o1;
if ( a.indexb.index ) return 1;
return 0;
}
};
int pos = Collections.binarySearch(rewrites, op, comparator);
if ( pos<0 ) {
rewrites.add(-pos-1, op);
}
}
public void insertAfter(Token t, String text) {
insertAfter(DEFAULT_PROGRAM_NAME, t, text);
}
public void insertAfter(int index, String text) {
insertAfter(DEFAULT_PROGRAM_NAME, index, text);
}
public void insertAfter(String programName, Token t, String text) {
insertAfter(programName,((TokenWithIndex)t).getIndex(), text);
}
public void insertAfter(String programName, int index, String text) {
// to insert after, just insert before next index (even if past end)
insertBefore(programName,index+1, text);
}
public void insertBefore(Token t, String text) {
insertBefore(DEFAULT_PROGRAM_NAME, t, text);
}
public void insertBefore(int index, String text) {
insertBefore(DEFAULT_PROGRAM_NAME, index, text);
}
public void insertBefore(String programName, Token t, String text) {
insertBefore(programName, ((TokenWithIndex)t).getIndex(), text);
}
public void insertBefore(String programName, int index, String text) {
addToSortedRewriteList(programName, new InsertBeforeOp(index,text));
}
public void replace(int index, String text) {
replace(DEFAULT_PROGRAM_NAME, index, index, text);
}
public void replace(int from, int to, String text) {
replace(DEFAULT_PROGRAM_NAME, from, to, text);
}
public void replace(Token indexT, String text) {
replace(DEFAULT_PROGRAM_NAME, indexT, indexT, text);
}
public void replace(Token from, Token to, String text) {
replace(DEFAULT_PROGRAM_NAME, from, to, text);
}
public void replace(String programName, int from, int to, String text) {
addToSortedRewriteList(new ReplaceOp(from, to, text));
}
public void replace(String programName, Token from, Token to, String text) {
replace(programName,
((TokenWithIndex)from).getIndex(),
((TokenWithIndex)to).getIndex(),
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 void discard(int ttype) {
discardMask.add(ttype);
}
public TokenWithIndex getToken(int i) {
return (TokenWithIndex)tokens.get(i);
}
public int getTokenStreamSize() {
return tokens.size();
}
public String toOriginalString() {
return toOriginalString(MIN_TOKEN_INDEX, getTokenStreamSize()-1);
}
public String toOriginalString(int start, int end) {
StringBuffer buf = new StringBuffer();
for (int i=start; i>=MIN_TOKEN_INDEX && i<=end && i=MIN_TOKEN_INDEX &&
tokenCursor<=end &&
tokenCursor=MIN_TOKEN_INDEX && i<=end && i
