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With inspiration from other libraries
// © 2016 and later: Unicode, Inc. and others.
// License & terms of use: http://www.unicode.org/copyright.html#License
/*
***************************************************************************
* Copyright (C) 2002-2009 International Business Machines Corporation *
* and others. All rights reserved. *
***************************************************************************
*/
package com.ibm.icu.text;
import java.text.ParsePosition;
import java.util.HashMap;
import com.ibm.icu.lang.UCharacter;
class RBBISymbolTable implements SymbolTable{
HashMap fHashTable;
RBBIRuleScanner fRuleScanner;
// These next two fields are part of the mechanism for passing references to
// already-constructed UnicodeSets back to the UnicodeSet constructor
// when the pattern includes $variable references.
String ffffString;
UnicodeSet fCachedSetLookup;
static class RBBISymbolTableEntry {
String key;
RBBINode val;
}
RBBISymbolTable(RBBIRuleScanner rs) {
fRuleScanner = rs;
fHashTable = new HashMap();
ffffString = "\uffff";
}
//
// RBBISymbolTable::lookup This function from the abstract symbol table inteface
// looks up a variable name and returns a UnicodeString
// containing the substitution text.
//
// The variable name does NOT include the leading $.
//
public char[] lookup(String s) {
RBBISymbolTableEntry el;
RBBINode varRefNode;
RBBINode exprNode;
RBBINode usetNode;
String retString;
el = fHashTable.get(s);
if (el == null) {
return null;
}
// Walk through any chain of variable assignments that ultimately resolve to a Set Ref.
varRefNode = el.val;
while (varRefNode.fLeftChild.fType == RBBINode.varRef) {
varRefNode = varRefNode.fLeftChild;
}
exprNode = varRefNode.fLeftChild; // Root node of expression for variable
if (exprNode.fType == RBBINode.setRef) {
// The $variable refers to a single UnicodeSet
// return the ffffString, which will subsequently be interpreted as a
// stand-in character for the set by RBBISymbolTable::lookupMatcher()
usetNode = exprNode.fLeftChild;
fCachedSetLookup = usetNode.fInputSet;
retString = ffffString;
} else {
// The variable refers to something other than just a set.
// This is an error in the rules being compiled. $Variables inside of UnicodeSets
// must refer only to another set, not to some random non-set expression.
// Note: single characters are represented as sets, so they are ok.
fRuleScanner.error(RBBIRuleBuilder.U_BRK_MALFORMED_SET);
retString = exprNode.fText;
fCachedSetLookup = null;
}
return retString.toCharArray();
}
//
// RBBISymbolTable::lookupMatcher This function from the abstract symbol table
// interface maps a single stand-in character to a
// pointer to a Unicode Set. The Unicode Set code uses this
// mechanism to get all references to the same $variable
// name to refer to a single common Unicode Set instance.
//
// This implementation cheats a little, and does not maintain a map of stand-in chars
// to sets. Instead, it takes advantage of the fact that the UnicodeSet
// constructor will always call this function right after calling lookup(),
// and we just need to remember what set to return between these two calls.
public UnicodeMatcher lookupMatcher(int ch) {
UnicodeSet retVal = null;
if (ch == 0xffff) {
retVal = fCachedSetLookup;
fCachedSetLookup = null;
}
return retVal;
}
//
// RBBISymbolTable::parseReference This function from the abstract symbol table interface
// looks for a $variable name in the source text.
// It does not look it up, only scans for it.
// It is used by the UnicodeSet parser.
//
public String parseReference(String text, ParsePosition pos, int limit) {
int start = pos.getIndex();
int i = start;
String result = "";
while (i < limit) {
int c = UTF16.charAt(text, i);
if ((i == start && !UCharacter.isUnicodeIdentifierStart(c))
|| !UCharacter.isUnicodeIdentifierPart(c)) {
break;
}
i += UTF16.getCharCount(c);
}
if (i == start) { // No valid name chars
return result; // Indicate failure with empty string
}
pos.setIndex(i);
result = text.substring(start, i);
return result;
}
//
// RBBISymbolTable::lookupNode Given a key (a variable name), return the
// corresponding RBBI Node. If there is no entry
// in the table for this name, return NULL.
//
RBBINode lookupNode(String key) {
RBBINode retNode = null;
RBBISymbolTableEntry el;
el = fHashTable.get(key);
if (el != null) {
retNode = el.val;
}
return retNode;
}
//
// RBBISymbolTable::addEntry Add a new entry to the symbol table.
// Indicate an error if the name already exists -
// this will only occur in the case of duplicate
// variable assignments.
//
void addEntry(String key, RBBINode val) {
RBBISymbolTableEntry e;
e = fHashTable.get(key);
if (e != null) {
fRuleScanner.error(RBBIRuleBuilder.U_BRK_VARIABLE_REDFINITION);
return;
}
e = new RBBISymbolTableEntry();
e.key = key;
e.val = val;
fHashTable.put(e.key, e);
}
//
// RBBISymbolTable::print Debugging function, dump out the symbol table contents.
//
///CLOVER:OFF
void rbbiSymtablePrint() {
System.out
.print("Variable Definitions\n"
+ "Name Node Val String Val\n"
+ "----------------------------------------------------------------------\n");
RBBISymbolTableEntry[] syms = fHashTable.values().toArray(new RBBISymbolTableEntry[0]);
for (int i = 0; i < syms.length; i++) {
RBBISymbolTableEntry s = syms[i];
System.out.print(" " + s.key + " "); // TODO: format output into columns.
System.out.print(" " + s.val + " ");
System.out.print(s.val.fLeftChild.fText);
System.out.print("\n");
}
System.out.println("\nParsed Variable Definitions\n");
for (int i = 0; i < syms.length; i++) {
RBBISymbolTableEntry s = syms[i];
System.out.print(s.key);
s.val.fLeftChild.printTree(true);
System.out.print("\n");
}
}
///CLOVER:ON
}