/*
 * @(#)$Id: TotalDigitsFacet.java,v 1.14 2002/10/18 03:14:11 kk122374 Exp $
 *
 * Copyright 2001 Sun Microsystems, Inc. All Rights Reserved.
 * 
 * This software is the proprietary information of Sun Microsystems, Inc.  
 * Use is subject to license terms.
 * 
 */
package com.sun.msv.datatype.xsd;

import org.relaxng.datatype.DatatypeException;
import org.relaxng.datatype.ValidationContext;

/**
 * 'totalDigits' facet.
 *
 * this class holds these facet information and performs validation.
 * 
 * @author <a href="mailto:kohsuke.kawaguchi@eng.sun.com">Kohsuke KAWAGUCHI</a>
 */
public class TotalDigitsFacet extends DataTypeWithLexicalConstraintFacet {
	/** maximum number of total digits. */
	public final int		precision;

	public TotalDigitsFacet( String nsUri, String typeName, XSDatatypeImpl baseType, TypeIncubator facets )
		throws DatatypeException {
		super( nsUri, typeName, baseType, FACET_TOTALDIGITS, facets );
		
		precision = facets.getPositiveInteger(FACET_TOTALDIGITS);
		
		// loosened facet check
		DataTypeWithFacet o = baseType.getFacetObject(FACET_TOTALDIGITS);
		if(o!=null && ((TotalDigitsFacet)o).precision < this.precision )
			throw new DatatypeException( localize( ERR_LOOSENED_FACET,
				FACET_TOTALDIGITS, o.displayName() ) );
		
		// consistency with scale is checked in XSDatatypeImpl.derive method.
	}

	protected boolean checkLexicalConstraint( String content ) {
		return countPrecision(content)<=precision;
	}
	
	protected void diagnoseByFacet(String content, ValidationContext context) throws DatatypeException {
		final int cnt = countPrecision(content);
		if( cnt<=precision )	return;
		
		throw new DatatypeException( DatatypeException.UNKNOWN,
			localize(ERR_TOO_MUCH_PRECISION, new Integer(cnt), new Integer(precision)) );
	}
	
	/** counts the number of digits */
	protected static int countPrecision( String literal ) {
		final int len = literal.length();
		boolean skipMode = true;
        boolean seenDot = false;
        
		int count=0;
		int trailingZero=0;
		
		for( int i=0; i<len; i++ ) {
			final char ch = literal.charAt(i);
            
            if(ch=='.') {
                skipMode = false;// digits after '.' is considered significant.
                seenDot = true;
            }
            
			if( skipMode ) {
				// in skip mode, leading zeros are skipped
				if( '1'<=ch && ch<='9' ) {
					count++;
					skipMode = false;
				}
			} else {
				if( seenDot && ch=='0' )    trailingZero++;
				else			            trailingZero=0;
				
				if( '0'<=ch && ch<='9' )
					count++;
			}
		}
		
		return count-trailingZero;
	}
}