package client.net.sf.saxon.ce.expr;
import client.net.sf.saxon.ce.expr.sort.AtomicComparer;
import client.net.sf.saxon.ce.expr.sort.CodepointCollator;
import client.net.sf.saxon.ce.expr.sort.GenericAtomicComparer;
import client.net.sf.saxon.ce.functions.NumberFn;
import client.net.sf.saxon.ce.lib.StringCollator;
import client.net.sf.saxon.ce.om.Item;
import client.net.sf.saxon.ce.om.SequenceIterator;
import client.net.sf.saxon.ce.trans.XPathException;
import client.net.sf.saxon.ce.type.BuiltInAtomicType;
import client.net.sf.saxon.ce.type.ItemType;
import client.net.sf.saxon.ce.type.TypeHierarchy;
import client.net.sf.saxon.ce.value.AtomicValue;
import client.net.sf.saxon.ce.value.BooleanValue;
import client.net.sf.saxon.ce.value.DoubleValue;
import client.net.sf.saxon.ce.value.StringValue;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
/**
* GeneralComparison10: a boolean expression that compares two expressions
* for equals, not-equals, greater-than or less-than. This implements the operators
* =, !=, <, >, etc. This version of the class implements general comparisons
* in XPath 1.0 backwards compatibility mode, as defined in the Oct 2004 revision
* of the specifications.
*/
public class GeneralComparison10 extends BinaryExpression {
protected int singletonOperator;
protected AtomicComparer comparer;
private boolean atomize0 = true;
private boolean atomize1 = true;
private boolean maybeBoolean0 = true;
private boolean maybeBoolean1 = true;
/**
* Create a general comparison identifying the two operands and the operator
* @param p0 the left-hand operand
* @param op the operator, as a token returned by the Tokenizer (e.g. Token.LT)
* @param p1 the right-hand operand
*/
public GeneralComparison10(Expression p0, int op, Expression p1) {
super(p0, op, p1);
singletonOperator = getSingletonOperator(op);
}
/**
* Determine the static cardinality. Returns [1..1]
*/
public int computeCardinality() {
return StaticProperty.EXACTLY_ONE;
}
/**
* Type-check the expression
* @return the checked expression
*/
public Expression typeCheck(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException {
operand0 = visitor.typeCheck(operand0, contextItemType);
operand1 = visitor.typeCheck(operand1, contextItemType);
StaticContext env = visitor.getStaticContext();
StringCollator comp = env.getConfiguration().getNamedCollation(env.getDefaultCollationName());
if (comp==null) {
comp = CodepointCollator.getInstance();
}
XPathContext context = env.makeEarlyEvaluationContext();
comparer = new GenericAtomicComparer(comp, context);
// evaluate the expression now if both arguments are constant
if ((operand0 instanceof Literal) && (operand1 instanceof Literal)) {
return Literal.makeLiteral((AtomicValue)evaluateItem(context));
}
return this;
}
public void setAtomicComparer(AtomicComparer comparer) {
this.comparer = comparer;
}
/**
* Optimize the expression
* @return the checked expression
*/
public Expression optimize(ExpressionVisitor visitor, ItemType contextItemType) throws XPathException {
Optimizer opt = visitor.getConfiguration().getOptimizer();
StaticContext env = visitor.getStaticContext();
operand0 = visitor.optimize(operand0, contextItemType);
operand1 = visitor.optimize(operand1, contextItemType);
// Neither operand needs to be sorted
operand0 = ExpressionTool.unsorted(opt, operand0, false);
operand1 = ExpressionTool.unsorted(opt, operand1, false);
// evaluate the expression now if both arguments are constant
if ((operand0 instanceof Literal) && (operand1 instanceof Literal)) {
return Literal.makeLiteral(
(AtomicValue)evaluateItem(env.makeEarlyEvaluationContext()));
}
final TypeHierarchy th = env.getConfiguration().getTypeHierarchy();
ItemType type0 = operand0.getItemType(th);
ItemType type1 = operand1.getItemType(th);
if (type0.isAtomicType()) {
atomize0 = false;
}
if (type1.isAtomicType()) {
atomize1 = false;
}
if (th.relationship(type0, BuiltInAtomicType.BOOLEAN) == TypeHierarchy.DISJOINT) {
maybeBoolean0 = false;
}
if (th.relationship(type1, BuiltInAtomicType.BOOLEAN) == TypeHierarchy.DISJOINT) {
maybeBoolean1 = false;
}
if (!maybeBoolean0 && !maybeBoolean1) {
int n0 = th.relationship(type0, BuiltInAtomicType.NUMERIC);
int n1 = th.relationship(type1, BuiltInAtomicType.NUMERIC);
boolean maybeNumeric0 = (n0 != TypeHierarchy.DISJOINT);
boolean maybeNumeric1 = (n1 != TypeHierarchy.DISJOINT);
boolean numeric0 = (n0 == TypeHierarchy.SUBSUMED_BY || n0 == TypeHierarchy.SAME_TYPE);
boolean numeric1 = (n1 == TypeHierarchy.SUBSUMED_BY || n1 == TypeHierarchy.SAME_TYPE);
// Use the 2.0 path if we don't have to deal with the possibility of boolean values,
// or the complications of converting values to numbers
if (operator == Token.EQUALS || operator == Token.NE) {
if ((!maybeNumeric0 && !maybeNumeric1) || (numeric0 && numeric1)) {
GeneralComparison gc = new GeneralComparison20(operand0, operator, operand1);
BinaryExpression binExp = visitor.getConfiguration().getOptimizer().simplifyGeneralComparison(gc, false);
ExpressionTool.copyLocationInfo(this, binExp);
return visitor.optimize(visitor.typeCheck(binExp, contextItemType), contextItemType);
}
} else if (numeric0 && numeric1) {
GeneralComparison gc = new GeneralComparison20(operand0, operator, operand1);
BinaryExpression binExp = visitor.getConfiguration().getOptimizer().simplifyGeneralComparison(gc, false);
ExpressionTool.copyLocationInfo(this, binExp);
return visitor.optimize(visitor.typeCheck(binExp, contextItemType), contextItemType);
}
}
return this;
}
/**
* Evaluate the expression in a given context
* @param context the given context for evaluation
* @return a BooleanValue representing the result of the numeric comparison of the two operands
*/
public Item evaluateItem(XPathContext context) throws XPathException {
return BooleanValue.get(effectiveBooleanValue(context));
}
/**
* Evaluate the expression in a boolean context
* @param context the given context for evaluation
* @return a boolean representing the result of the numeric comparison of the two operands
*/
public boolean effectiveBooleanValue(XPathContext context) throws XPathException {
// If the first operand is a singleton boolean,
// compare it with the effective boolean value of the other operand
SequenceIterator iter0 = null;
if (maybeBoolean0) {
iter0 = operand0.iterate(context);
Item i01 = iter0.next();
Item i02 = (i01 == null ? null : iter0.next());
if (i01 instanceof BooleanValue && i02 == null) {
boolean b = operand1.effectiveBooleanValue(context);
return compare((BooleanValue)i01, singletonOperator, BooleanValue.get(b), comparer, context);
}
if (i01 == null && !maybeBoolean1) {
return false;
}
}
// If the second operand is a singleton boolean,
// compare it with the effective boolean value of the other operand
SequenceIterator iter1 = null;
if (maybeBoolean1) {
iter1 = operand1.iterate(context);
Item i11 = iter1.next();
Item i12 = (i11 == null ? null : iter1.next());
if (i11 instanceof BooleanValue && i12 == null) {
boolean b = operand0.effectiveBooleanValue(context);
return compare(BooleanValue.get(b), singletonOperator, (BooleanValue)i11, comparer, context);
}
if (i11 == null && !maybeBoolean0) {
return false;
}
}
// Atomize both operands where necessary
if (iter0 == null) {
iter0 = operand0.iterate(context);
} else {
iter0 = iter0.getAnother();
}
if (iter1 == null) {
iter1 = operand1.iterate(context);
} else {
iter1 = iter1.getAnother();
}
if (atomize0) {
iter0 = Atomizer.getAtomizingIterator(iter0);
}
if (atomize1) {
iter1 = Atomizer.getAtomizingIterator(iter1);
}
// If the operator is one of <, >, <=, >=, then convert both operands to sequences of xs:double
// using the number() function
if (operator == Token.LT || operator == Token.LE || operator == Token.GT || operator == Token.GE) {
ItemMappingFunction map = new ItemMappingFunction() {
public Item mapItem(Item item) throws XPathException {
return NumberFn.convert((AtomicValue)item);
}
};
iter0 = new ItemMappingIterator(iter0, map, true);
iter1 = new ItemMappingIterator(iter1, map, true);
}
// Compare all pairs of atomic values in the two atomized sequences
List seq1 = null;
while (true) {
AtomicValue item0 = (AtomicValue)iter0.next();
if (item0 == null) {
return false;
}
if (iter1 != null) {
while (true) {
AtomicValue item1 = (AtomicValue)iter1.next();
if (item1 == null) {
iter1 = null;
if (seq1 == null) {
// second operand is empty
return false;
}
break;
}
try {
if (compare(item0, singletonOperator, item1, comparer, context)) {
return true;
}
if (seq1 == null) {
seq1 = new ArrayList(40);
}
seq1.add(item1);
} catch (XPathException e) {
// re-throw the exception with location information added
e.maybeSetLocation(this.getSourceLocator());
e.maybeSetContext(context);
throw e;
}
}
} else {
//assert seq1 != null;
Iterator listIter1 = seq1.iterator();
while (listIter1.hasNext()) {
AtomicValue item1 = (AtomicValue)listIter1.next();
if (compare(item0, singletonOperator, item1, comparer, context)) {
return true;
}
}
}
}
}
/**
* Compare two atomic values
* @param a0 the first value to be compared
* @param operator the comparison operator
* @param a1 the second value to be compared
* @param comparer the comparer to be used (perhaps including a collation)
* @param context the XPath dynamic context
* @return the result of the comparison
*/
private static boolean compare(AtomicValue a0,
int operator,
AtomicValue a1,
AtomicComparer comparer,
XPathContext context) throws XPathException {
comparer = comparer.provideContext(context);
BuiltInAtomicType t0 = a0.getPrimitiveType();
BuiltInAtomicType t1 = a1.getPrimitiveType();
// If either operand is a number, convert both operands to xs:double using
// the rules of the number() function, and compare them
if (t0.isPrimitiveNumeric() || t1.isPrimitiveNumeric()) {
DoubleValue v0 = NumberFn.convert(a0);
DoubleValue v1 = NumberFn.convert(a1);
return ValueComparison.compare(v0, operator, v1, comparer, false);
}
// If either operand is a string, or if both are untyped atomic, convert
// both operands to strings and compare them
if (t0.equals(BuiltInAtomicType.STRING) || t1.equals(BuiltInAtomicType.STRING) ||
(t0.equals(BuiltInAtomicType.UNTYPED_ATOMIC) && t1.equals(BuiltInAtomicType.UNTYPED_ATOMIC))) {
StringValue s0 = (StringValue)a0.convert(BuiltInAtomicType.STRING, true).asAtomic();
StringValue s1 = (StringValue)a1.convert(BuiltInAtomicType.STRING, true).asAtomic();
return ValueComparison.compare(s0, operator, s1, comparer, false);
}
// If either operand is untyped atomic,
// convert it to the type of the other operand, and compare
if (t0.equals(BuiltInAtomicType.UNTYPED_ATOMIC)) {
a0 = a0.convert(t1, true).asAtomic();
}
if (t1.equals(BuiltInAtomicType.UNTYPED_ATOMIC)) {
a1 = a1.convert(t0, true).asAtomic();
}
return ValueComparison.compare(a0, operator, a1, comparer, false);
}
/**
* Determine the data type of the expression
* @return Type.BOOLEAN
* @param th the type hierarchy cache
*/
public ItemType getItemType(TypeHierarchy th) {
return BuiltInAtomicType.BOOLEAN;
}
/**
* Return the singleton form of the comparison operator, e.g. FEQ for EQUALS, FGT for GT
* @param op the general comparison operator, for example Token.EQUALS
* @return the corresponding value comparison operator, for example Token.FEQ
*/
private static int getSingletonOperator(int op) {
switch (op) {
case Token.EQUALS:
return Token.FEQ;
case Token.GE:
return Token.FGE;
case Token.NE:
return Token.FNE;
case Token.LT:
return Token.FLT;
case Token.GT:
return Token.FGT;
case Token.LE:
return Token.FLE;
default:
return op;
}
}
}
// This Source Code Form is subject to the terms of the Mozilla Public License, v. 2.0.
// If a copy of the MPL was not distributed with this file, You can obtain one at http://mozilla.org/MPL/2.0/.
// This Source Code Form is “Incompatible With Secondary Licenses”, as defined by the Mozilla Public License, v. 2.0.