com.ibm.icu.text.RBBINode Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of icu4j Show documentation
Show all versions of icu4j Show documentation
International Component for Unicode for Java (ICU4J) is a mature, widely used Java library
providing Unicode and Globalization support
// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html#License
/********************************************************************
* COPYRIGHT:
* Copyright (c) 2001-2016, International Business Machines Corporation and
* others. All Rights Reserved.
********************************************************************/
package com.ibm.icu.text;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import com.ibm.icu.impl.Assert;
/**
* This class represents a node in the parse tree created by the RBBI Rule compiler.
*/
class RBBINode {
// enum NodeType {
static final int setRef = 0;
static final int uset = 1;
static final int varRef = 2;
static final int leafChar = 3;
static final int lookAhead = 4;
static final int tag = 5;
static final int endMark = 6;
static final int opStart = 7;
static final int opCat = 8;
static final int opOr = 9;
static final int opStar = 10;
static final int opPlus = 11;
static final int opQuestion = 12;
static final int opBreak = 13;
static final int opReverse = 14;
static final int opLParen = 15;
static final int nodeTypeLimit = 16; // For Assertion checking only.
static final String [] nodeTypeNames = {
"setRef",
"uset",
"varRef",
"leafChar",
"lookAhead",
"tag",
"endMark",
"opStart",
"opCat",
"opOr",
"opStar",
"opPlus",
"opQuestion",
"opBreak",
"opReverse",
"opLParen"
};
// enum OpPrecedence {
static final int precZero = 0;
static final int precStart = 1;
static final int precLParen = 2;
static final int precOpOr = 3;
static final int precOpCat = 4;
int fType; // enum NodeType
RBBINode fParent;
RBBINode fLeftChild;
RBBINode fRightChild;
UnicodeSet fInputSet; // For uset nodes only.
int fPrecedence = precZero; // enum OpPrecedence, For binary ops only.
String fText; // Text corresponding to this node.
// May be lazily evaluated when (if) needed
// for some node types.
int fFirstPos; // Position in the rule source string of the
// first text associated with the node.
// If there's a left child, this will be the same
// as that child's left pos.
int fLastPos; // Last position in the rule source string
// of any text associated with this node.
// If there's a right child, this will be the same
// as that child's last postion.
boolean fNullable; // See Aho DFA table generation algorithm
int fVal; // For leafChar nodes, the value.
// Values are the character category,
// corresponds to columns in the final
// state transition table.
boolean fLookAheadEnd; // For endMark nodes, set TRUE if
// marking the end of a look-ahead rule.
boolean fRuleRoot; // True if this node is the root of a rule.
boolean fChainIn; // True if chaining into this rule is allowed
// (no '^' present).
Set fFirstPosSet; // See Aho DFA table generation algorithm
Set fLastPosSet; // See Aho.
Set fFollowPos; // See Aho.
int fSerialNum; // Debugging aids. Each node gets a unique serial number.
static int gLastSerial;
RBBINode(int t) {
Assert.assrt(t < nodeTypeLimit);
fSerialNum = ++gLastSerial;
fType = t;
fFirstPosSet = new HashSet();
fLastPosSet = new HashSet();
fFollowPos = new HashSet();
if (t == opCat) {
fPrecedence = precOpCat;
} else if (t == opOr) {
fPrecedence = precOpOr;
} else if (t == opStart) {
fPrecedence = precStart;
} else if (t == opLParen) {
fPrecedence = precLParen;
} else {
fPrecedence = precZero;
}
}
RBBINode(RBBINode other) {
fSerialNum = ++gLastSerial;
fType = other.fType;
fInputSet = other.fInputSet;
fPrecedence = other.fPrecedence;
fText = other.fText;
fFirstPos = other.fFirstPos;
fLastPos = other.fLastPos;
fNullable = other.fNullable;
fVal = other.fVal;
fRuleRoot = false;
fChainIn = other.fChainIn;
fFirstPosSet = new HashSet(other.fFirstPosSet);
fLastPosSet = new HashSet(other.fLastPosSet);
fFollowPos = new HashSet(other.fFollowPos);
}
//-------------------------------------------------------------------------
//
// cloneTree Make a copy of the subtree rooted at this node.
// Discard any variable references encountered along the way,
// and replace with copies of the variable's definitions.
// Used to replicate the expression underneath variable
// references in preparation for generating the DFA tables.
//
//-------------------------------------------------------------------------
RBBINode cloneTree() {
RBBINode n;
if (fType == RBBINode.varRef) {
// If the current node is a variable reference, skip over it
// and clone the definition of the variable instead.
n = fLeftChild.cloneTree();
} else if (fType == RBBINode.uset) {
n = this;
} else {
n = new RBBINode(this);
if (fLeftChild != null) {
n.fLeftChild = fLeftChild.cloneTree();
n.fLeftChild.fParent = n;
}
if (fRightChild != null) {
n.fRightChild = fRightChild.cloneTree();
n.fRightChild.fParent = n;
}
}
return n;
}
//-------------------------------------------------------------------------
//
// flattenVariables Walk a parse tree, replacing any variable
// references with a copy of the variable's definition.
// Aside from variables, the tree is not changed.
//
// Return the root of the tree. If the root was not a variable
// reference, it remains unchanged - the root we started with
// is the root we return. If, however, the root was a variable
// reference, the root of the newly cloned replacement tree will
// be returned, and the original tree deleted.
//
// This function works by recursively walking the tree
// without doing anything until a variable reference is
// found, then calling cloneTree() at that point. Any
// nested references are handled by cloneTree(), not here.
//
//-------------------------------------------------------------------------
RBBINode flattenVariables() {
if (fType == varRef) {
RBBINode retNode = fLeftChild.cloneTree();
retNode.fRuleRoot = this.fRuleRoot;
retNode.fChainIn = this.fChainIn;
return retNode;
}
if (fLeftChild != null) {
fLeftChild = fLeftChild.flattenVariables();
fLeftChild.fParent = this;
}
if (fRightChild != null) {
fRightChild = fRightChild.flattenVariables();
fRightChild.fParent = this;
}
return this;
}
//-------------------------------------------------------------------------
//
// flattenSets Walk the parse tree, replacing any nodes of type setRef
// with a copy of the expression tree for the set. A set's
// equivalent expression tree is precomputed and saved as
// the left child of the uset node.
//
//-------------------------------------------------------------------------
void flattenSets() {
Assert.assrt(fType != setRef);
if (fLeftChild != null) {
if (fLeftChild.fType == setRef) {
RBBINode setRefNode = fLeftChild;
RBBINode usetNode = setRefNode.fLeftChild;
RBBINode replTree = usetNode.fLeftChild;
fLeftChild = replTree.cloneTree();
fLeftChild.fParent = this;
} else {
fLeftChild.flattenSets();
}
}
if (fRightChild != null) {
if (fRightChild.fType == setRef) {
RBBINode setRefNode = fRightChild;
RBBINode usetNode = setRefNode.fLeftChild;
RBBINode replTree = usetNode.fLeftChild;
fRightChild = replTree.cloneTree();
fRightChild.fParent = this;
// delete setRefNode;
} else {
fRightChild.flattenSets();
}
}
}
//-------------------------------------------------------------------------
//
// findNodes() Locate all the nodes of the specified type, starting
// at the specified root.
//
//-------------------------------------------------------------------------
void findNodes(List dest, int kind) {
if (fType == kind) {
dest.add(this);
}
if (fLeftChild != null) {
fLeftChild.findNodes(dest, kind);
}
if (fRightChild != null) {
fRightChild.findNodes(dest, kind);
}
}
//-------------------------------------------------------------------------
//
// print. Print out a single node, for debugging.
//
//-------------------------------------------------------------------------
///CLOVER:OFF
static void printNode(RBBINode n) {
if (n==null) {
System.out.print (" -- null --\n");
} else {
RBBINode.printInt( n.fSerialNum, 10);
RBBINode.printString(nodeTypeNames[n.fType], 11);
RBBINode.printInt(n.fParent==null? 0 : n.fParent.fSerialNum, 11);
RBBINode.printInt(n.fLeftChild==null? 0 : n.fLeftChild.fSerialNum, 11);
RBBINode.printInt(n.fRightChild==null? 0 : n.fRightChild.fSerialNum, 12);
RBBINode.printInt(n.fFirstPos, 12);
RBBINode.printInt(n.fVal, 7);
if (n.fType == varRef) {
System.out.print(" " + n.fText);
}
}
System.out.println("");
}
///CLOVER:ON
// Print a String in a fixed field size.
// Debugging function.
///CLOVER:OFF
static void printString(String s, int minWidth) {
for (int i = minWidth; i < 0; i++) {
// negative width means pad leading spaces, not fixed width.
System.out.print(' ');
}
for (int i = s.length(); i < minWidth; i++) {
System.out.print(' ');
}
System.out.print(s);
}
///CLOVER:ON
//
// Print an int in a fixed size field.
// Debugging function.
//
///CLOVER:OFF
static void printInt(int i, int minWidth) {
String s = Integer.toString(i);
printString(s, Math.max(minWidth, s.length() + 1));
}
///CLOVER:ON
///CLOVER:OFF
static void printHex(int i, int minWidth) {
String s = Integer.toString(i, 16);
String leadingZeroes = "00000"
.substring(0, Math.max(0, 5 - s.length()));
s = leadingZeroes + s;
printString(s, minWidth);
}
///CLOVER:ON
// -------------------------------------------------------------------------
//
// print. Print out the tree of nodes rooted at "this"
//
// -------------------------------------------------------------------------
///CLOVER:OFF
void printTree(boolean printHeading) {
if (printHeading) {
System.out.println( "-------------------------------------------------------------------");
System.out.println(" Serial type Parent LeftChild RightChild position value");
}
printNode(this);
// Only dump the definition under a variable reference if asked to.
// Unconditinally dump children of all other node types.
if (fType != varRef) {
if (fLeftChild != null) {
fLeftChild.printTree(false);
}
if (fRightChild != null) {
fRightChild.printTree(false);
}
}
}
///CLOVER:ON
}