/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/* $Id$ */

package org.apache.fop.complexscripts.fonts;

import org.apache.fop.complexscripts.util.GlyphSequence;
import org.apache.fop.complexscripts.util.ScriptContextTester;

// CSOFF: LineLengthCheck

The GlyphPositioningSubtable implements an abstract base of a glyph subtable,
providing a default implementation of the GlyphPositioning interface.
This work was originally authored by Glenn Adams (gadams@apache.org).
/**
 * <p>The <code>GlyphPositioningSubtable</code> implements an abstract base of a glyph subtable,
 * providing a default implementation of the <code>GlyphPositioning</code> interface.</p>
 *
 * <p>This work was originally authored by Glenn Adams (gadams@apache.org).</p>
 */
public abstract class GlyphPositioningSubtable extends GlyphSubtable implements GlyphPositioning {

    private static final GlyphPositioningState STATE = new GlyphPositioningState();

    
Instantiate a GlyphPositioningSubtable.
Params:
id – subtable identifier
sequence – subtable sequence
flags – subtable flags
format – subtable format
coverage – subtable coverage table/**
     * Instantiate a <code>GlyphPositioningSubtable</code>.
     * @param id subtable identifier
     * @param sequence subtable sequence
     * @param flags subtable flags
     * @param format subtable format
     * @param coverage subtable coverage table
     */
    protected GlyphPositioningSubtable(String id, int sequence, int flags, int format, GlyphCoverageTable coverage) {
        super(id, sequence, flags, format, coverage);
    }

    
{@inheritDoc} /** {@inheritDoc} */
    public int getTableType() {
        return GlyphTable.GLYPH_TABLE_TYPE_POSITIONING;
    }

    
{@inheritDoc} /** {@inheritDoc} */
    public String getTypeName() {
        return GlyphPositioningTable.getLookupTypeName(getType());
    }

    
{@inheritDoc} /** {@inheritDoc} */
    public boolean isCompatible(GlyphSubtable subtable) {
        return subtable instanceof GlyphPositioningSubtable;
    }

    
{@inheritDoc} /** {@inheritDoc} */
    public boolean usesReverseScan() {
        return false;
    }

    
{@inheritDoc} /** {@inheritDoc} */
    public boolean position(GlyphPositioningState ps) {
        return false;
    }

    
Apply positioning using specified state and subtable array. For each position in input sequence,
apply subtables in order until some subtable applies or none remain. If no subtable applied or no
input was consumed for a given position, then apply default action (no adjustments and advance).
If sequenceIndex is non-negative, then apply subtables only when current position
matches sequenceIndex in relation to the starting position. Furthermore, upon
successful application at sequenceIndex, then discontinue processing the remaining
Params:
ps – positioning state
sta – array of subtables to apply
sequenceIndex – if non negative, then apply subtables only at specified sequence index
Returns:
true if a non-zero adjustment occurred/**
     * Apply positioning using specified state and subtable array. For each position in input sequence,
     * apply subtables in order until some subtable applies or none remain. If no subtable applied or no
     * input was consumed for a given position, then apply default action (no adjustments and advance).
     * If <code>sequenceIndex</code> is non-negative, then apply subtables only when current position
     * matches <code>sequenceIndex</code> in relation to the starting position. Furthermore, upon
     * successful application at <code>sequenceIndex</code>, then discontinue processing the remaining
     * @param ps positioning state
     * @param sta array of subtables to apply
     * @param sequenceIndex if non negative, then apply subtables only at specified sequence index
     * @return true if a non-zero adjustment occurred
     */
    public static final boolean position(GlyphPositioningState ps, GlyphPositioningSubtable[] sta, int sequenceIndex) {
        int sequenceStart = ps.getPosition();
        boolean appliedOneShot = false;
        while (ps.hasNext()) {
            boolean applied = false;
            if (!appliedOneShot && ps.maybeApplicable()) {
                for (int i = 0, n = sta.length; !applied && (i < n); i++) {
                    if (sequenceIndex < 0) {
                        applied = ps.apply(sta [ i ]);
                    } else if (ps.getPosition() == (sequenceStart + sequenceIndex)) {
                        applied = ps.apply(sta [ i ]);
                        if (applied) {
                            appliedOneShot = true;
                        }
                    }
                }
            }
            if (!applied || !ps.didConsume()) {
                ps.applyDefault();
            }
            ps.next();
        }
        return ps.getAdjusted();
    }

    
Apply positioning.
Params:
gs – input glyph sequence
script – tag
language – tag
feature – tag
fontSize – the font size
sta – subtable array
widths – array
adjustments – array (receives output adjustments)
sct – script context tester
Returns:
true if a non-zero adjustment occurred/**
     * Apply positioning.
     * @param gs input glyph sequence
     * @param script tag
     * @param language tag
     * @param feature tag
     * @param fontSize the font size
     * @param sta subtable array
     * @param widths array
     * @param adjustments array (receives output adjustments)
     * @param sct script context tester
     * @return true if a non-zero adjustment occurred
     */
    public static final boolean position(GlyphSequence gs, String script, String language, String feature, int fontSize, GlyphPositioningSubtable[] sta, int[] widths, int[][] adjustments, ScriptContextTester sct) {
        synchronized (STATE) {
            return position(STATE.reset(gs, script, language, feature, fontSize, widths, adjustments, sct), sta, -1);
        }
    }

}