/*
* 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 java.nio.IntBuffer;
import java.util.ArrayList;
import java.util.List;
import org.apache.fop.complexscripts.util.GlyphSequence;
import org.apache.fop.complexscripts.util.ScriptContextTester;
// CSOFF: LineLengthCheck
// CSOFF: NoWhitespaceAfterCheck
/**
* <p>The <code>GlyphSubstitutionState</code> implements an state object used during glyph substitution
* processing.</p>
*
* <p>This work was originally authored by Glenn Adams (gadams@apache.org).</p>
*/
public class GlyphSubstitutionState extends GlyphProcessingState {
/** alternates index */
private int[] alternatesIndex;
/** current output glyph sequence */
private IntBuffer ogb;
/** current output glyph to character associations */
private List oal;
/** character association predications */
private boolean predications;
/**
* Construct glyph substitution state.
* @param gs input glyph sequence
* @param script script identifier
* @param language language identifier
* @param feature feature identifier
* @param sct script context tester (or null)
*/
public GlyphSubstitutionState ( GlyphSequence gs, String script, String language, String feature, ScriptContextTester sct ) {
super ( gs, script, language, feature, sct );
this.ogb = IntBuffer.allocate ( gs.getGlyphCount() );
this.oal = new ArrayList ( gs.getGlyphCount() );
this.predications = gs.getPredications();
}
/**
* Construct glyph substitution state using an existing state object using shallow copy
* except as follows: input glyph sequence is copied deep except for its characters array.
* @param ss existing positioning state to copy from
*/
public GlyphSubstitutionState ( GlyphSubstitutionState ss ) {
super ( ss );
this.ogb = IntBuffer.allocate ( indexLast );
this.oal = new ArrayList ( indexLast );
}
/**
* Set alternates indices.
* @param alternates array of alternates indices ordered by coverage index
*/
public void setAlternates ( int[] alternates ) {
this.alternatesIndex = alternates;
}
/**
* Obtain alternates index associated with specified coverage index. An alternates
* index is used to select among stylistic alternates of a glyph at a particular
* coverage index. This information must be provided by the document itself (in the
* form of an extension attribute value), since a font has no way to determine which
* alternate the user desires.
* @param ci coverage index
* @return an alternates index
*/
public int getAlternatesIndex ( int ci ) {
if ( alternatesIndex == null ) {
return 0;
} else if ( ( ci < 0 ) || ( ci > alternatesIndex.length ) ) {
return 0;
} else {
return alternatesIndex [ ci ];
}
}
/**
* Put (write) glyph into glyph output buffer.
* @param glyph to write
* @param a character association that applies to glyph
* @param predication a predication value to add to association A if predications enabled
*/
public void putGlyph ( int glyph, GlyphSequence.CharAssociation a, Object predication ) {
if ( ! ogb.hasRemaining() ) {
ogb = growBuffer ( ogb );
}
ogb.put ( glyph );
if ( predications && ( predication != null ) ) {
a.setPredication ( feature, predication );
}
oal.add ( a );
}
/**
* Put (write) array of glyphs into glyph output buffer.
* @param glyphs to write
* @param associations array of character associations that apply to glyphs
* @param predication optional predicaion object to be associated with glyphs' associations
*/
public void putGlyphs ( int[] glyphs, GlyphSequence.CharAssociation[] associations, Object predication ) {
assert glyphs != null;
assert associations != null;
assert associations.length >= glyphs.length;
for ( int i = 0, n = glyphs.length; i < n; i++ ) {
putGlyph ( glyphs [ i ], associations [ i ], predication );
}
}
/**
* Obtain output glyph sequence.
* @return newly constructed glyph sequence comprised of original
* characters, output glyphs, and output associations
*/
public GlyphSequence getOutput() {
int position = ogb.position();
if ( position > 0 ) {
ogb.limit ( position );
ogb.rewind();
return new GlyphSequence ( igs.getCharacters(), ogb, oal );
} else {
return igs;
}
}
/**
* Apply substitution subtable to current state at current position (only),
* resulting in the consumption of zero or more input glyphs, and possibly
* replacing the current input glyphs starting at the current position, in
* which case it is possible that indexLast is altered to be either less than
* or greater than its value prior to this application.
* @param st the glyph substitution subtable to apply
* @return true if subtable applied, or false if it did not (e.g., its
* input coverage table did not match current input context)
*/
public boolean apply ( GlyphSubstitutionSubtable st ) {
assert st != null;
updateSubtableState ( st );
boolean applied = st.substitute ( this );
resetSubtableState();
return applied;
}
/**
* Apply a sequence of matched rule lookups to the <code>nig</code> input glyphs
* starting at the current position. If lookups are non-null and non-empty, then
* all input glyphs specified by <code>nig</code> are consumed irregardless of
* whether any specified lookup applied.
* @param lookups array of matched lookups (or null)
* @param nig number of glyphs in input sequence, starting at current position, to which
* the lookups are to apply, and to be consumed once the application has finished
* @return true if lookups are non-null and non-empty; otherwise, false
*/
public boolean apply ( GlyphTable.RuleLookup[] lookups, int nig ) {
// int nbg = index;
int nlg = indexLast - ( index + nig );
int nog = 0;
if ( ( lookups != null ) && ( lookups.length > 0 ) ) {
// apply each rule lookup to extracted input glyph array
for ( int i = 0, n = lookups.length; i < n; i++ ) {
GlyphTable.RuleLookup l = lookups [ i ];
if ( l != null ) {
GlyphTable.LookupTable lt = l.getLookup();
if ( lt != null ) {
// perform substitution on a copy of previous state
GlyphSubstitutionState ss = new GlyphSubstitutionState ( this );
// apply lookup table substitutions
GlyphSequence gs = lt.substitute ( ss, l.getSequenceIndex() );
// replace current input sequence starting at current position with result
if ( replaceInput ( 0, -1, gs ) ) {
nog = gs.getGlyphCount() - nlg;
}
}
}
}
// output glyphs and associations
putGlyphs ( getGlyphs ( 0, nog, false, null, null, null ), getAssociations ( 0, nog, false, null, null, null ), null );
// consume replaced input glyphs
consume ( nog );
return true;
} else {
return false;
}
}
/**
* Apply default application semantices; namely, consume one input glyph,
* writing that glyph (and its association) to the output glyphs (and associations).
*/
public void applyDefault() {
super.applyDefault();
int gi = getGlyph();
if ( gi != 65535 ) {
putGlyph ( gi, getAssociation(), null );
}
}
private static IntBuffer growBuffer ( IntBuffer ib ) {
int capacity = ib.capacity();
int capacityNew = capacity * 2;
IntBuffer ibNew = IntBuffer.allocate ( capacityNew );
ib.rewind();
return ibNew.put ( ib );
}
}