/*
 * 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: CharacterSetBuilder.java 1761020 2016-09-16 11:17:35Z ssteiner $ */

package org.apache.fop.afp.fonts;

import java.awt.Rectangle;
import java.io.IOException;
import java.io.InputStream;
import java.net.MalformedURLException;
import java.net.URI;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import java.util.WeakHashMap;

import org.apache.commons.logging.Log;
import org.apache.commons.logging.LogFactory;

import org.apache.xmlgraphics.image.loader.util.SoftMapCache;

import org.apache.fop.afp.AFPConstants;
import org.apache.fop.afp.AFPEventProducer;
import org.apache.fop.afp.util.AFPResourceAccessor;
import org.apache.fop.afp.util.StructuredFieldReader;
import org.apache.fop.apps.io.InternalResourceResolver;
import org.apache.fop.fonts.Typeface;

The CharacterSetBuilder is responsible building the a CharacterSet instance that holds
the font metric data.  The data is either read from disk and passed to a CharacterSet (*)
or a FopCharacterSet is instantiated that is composed of a Typeface instance configured
with this data.

-*- For referenced fonts CharacterSetBuilder is responsible for reading the font attributes
from binary code page files and the character set metric files. In IBM font structure, a
code page maps each character of text to the characters in a character set.
Each character is translated into a code point. When the character is
printed, each code point is matched to a character ID on the code page
specified. The character ID is then matched to the image (raster pattern or
outline pattern) of the character in the character set specified. The image
in the character set is the image that is printed in the document. To be a
valid code page for a particular character set, all character IDs in the code
page must be included in that character set.

This class will read the font information from the binary code page files and character
set metric files in order to determine the correct metrics to use when rendering the
formatted object.
/**
 * The CharacterSetBuilder is responsible building the a CharacterSet instance that holds
 * the font metric data.  The data is either read from disk and passed to a CharacterSet (*)
 * or a FopCharacterSet is instantiated that is composed of a Typeface instance configured
 * with this data.<br>
 * -*- For referenced fonts CharacterSetBuilder is responsible for reading the font attributes
 * from binary code page files and the character set metric files. In IBM font structure, a
 * code page maps each character of text to the characters in a character set.
 * Each character is translated into a code point. When the character is
 * printed, each code point is matched to a character ID on the code page
 * specified. The character ID is then matched to the image (raster pattern or
 * outline pattern) of the character in the character set specified. The image
 * in the character set is the image that is printed in the document. To be a
 * valid code page for a particular character set, all character IDs in the code
 * page must be included in that character set.<br>
 * This class will read the font information from the binary code page files and character
 * set metric files in order to determine the correct metrics to use when rendering the
 * formatted object.
 */
public abstract class CharacterSetBuilder {

    
Static logging instance
/**
     * Static logging instance
     */
    protected static final Log LOG = LogFactory.getLog(CharacterSetBuilder.class);

    
Template used to convert lists to arrays.
/**
     * Template used to convert lists to arrays.
     */
    private static final CharacterSetOrientation[] EMPTY_CSO_ARRAY = new CharacterSetOrientation[0];

    
Codepage MO:DCA structured field. /** Codepage MO:DCA structured field. */
    private static final byte[] CODEPAGE_SF = new byte[] {
        (byte) 0xD3, (byte) 0xA8, (byte) 0x87};

    
Character table MO:DCA structured field. /** Character table MO:DCA structured field. */
    private static final byte[] CHARACTER_TABLE_SF = new byte[] {
        (byte) 0xD3, (byte) 0x8C, (byte) 0x87};

    
Font descriptor MO:DCA structured field. /** Font descriptor MO:DCA structured field. */
    private static final byte[] FONT_DESCRIPTOR_SF = new byte[] {
        (byte) 0xD3, (byte) 0xA6, (byte) 0x89 };

    
Font control MO:DCA structured field. /** Font control MO:DCA structured field. */
    private static final byte[] FONT_CONTROL_SF = new byte[] {
        (byte) 0xD3, (byte) 0xA7, (byte) 0x89 };

    
Font orientation MO:DCA structured field. /** Font orientation MO:DCA structured field. */
    private static final byte[] FONT_ORIENTATION_SF = new byte[] {
        (byte) 0xD3, (byte) 0xAE, (byte) 0x89 };

    
Font position MO:DCA structured field. /** Font position MO:DCA structured field. */
    private static final byte[] FONT_POSITION_SF = new byte[] {
        (byte) 0xD3, (byte) 0xAC, (byte) 0x89 };

    
Font index MO:DCA structured field. /** Font index MO:DCA structured field. */
    private static final byte[] FONT_INDEX_SF = new byte[] {
        (byte) 0xD3, (byte) 0x8C, (byte) 0x89 };

    
The collection of code pages
/**
     * The collection of code pages
     */
    private final Map<String, Map<String, String>> codePagesCache
            = Collections.synchronizedMap(new WeakHashMap<String, Map<String, String>>());

    
Cache of charactersets
/**
     * Cache of charactersets
     */
    private final SoftMapCache characterSetsCache = new SoftMapCache(true);

    
Default constructor. /** Default constructor. */
    private CharacterSetBuilder() {
    }

    
Factory method for the single-byte implementation of AFPFontReader.
Returns:
AFPFontReader/**
     * Factory method for the single-byte implementation of AFPFontReader.
     * @return AFPFontReader
     */
    public static CharacterSetBuilder getSingleByteInstance() {
        return SingleByteLoader.getInstance();
    }

    
Factory method for the double-byte (CID Keyed font (Type 0)) implementation of AFPFontReader.
Returns:
AFPFontReader/**
     * Factory method for the double-byte (CID Keyed font (Type 0)) implementation of AFPFontReader.
     * @return AFPFontReader
     */
    public static CharacterSetBuilder getDoubleByteInstance() {
        return DoubleByteLoader.getInstance();
    }


    
Returns an InputStream to a given file path and filename
Params:
accessor – the resource accessor
uriStr – the URI
eventProducer – for handling AFP related events
Throws:
IOException – in the event that an I/O exception of some sort has occurred
Returns:
an inputStream/**
     * Returns an InputStream to a given file path and filename
     *
     * @param accessor the resource accessor
     * @param uriStr the URI
     * @param eventProducer for handling AFP related events
     * @return an inputStream
     * @throws IOException in the event that an I/O exception of some sort has occurred
     */
    private InputStream openInputStream(AFPResourceAccessor accessor, String uriStr,
            AFPEventProducer eventProducer)
            throws IOException {
        URI uri;
        try {
            uri = InternalResourceResolver.cleanURI(uriStr.trim());
        } catch (URISyntaxException e) {
            throw new MalformedURLException("Invalid uri: " + uriStr + " (" + e.getMessage() + ")");
        }
        if (LOG.isDebugEnabled()) {
            LOG.debug("Opening " + uri);
        }
        return accessor.createInputStream(uri);
    }

    
Closes the inputstream
Params:
inputStream – the inputstream to close/**
     * Closes the inputstream
     *
     * @param inputStream the inputstream to close
     */
    private void closeInputStream(InputStream inputStream) {
        try {
            if (inputStream != null) {
                inputStream.close();
            }
        } catch (Exception ex) {
            // Lets log at least!
            LOG.error(ex.getMessage());
        }
    }

    
Load the font details and metrics into the CharacterSetMetric object, this will use the
actual afp code page and character set files to load the object with the necessary metrics.
Params:
characterSetName – name of the characterset
codePageName – name of the code page file
encoding – encoding name
accessor – used to load codepage and characterset
eventProducer – for handling AFP related events
Throws:
IOException – if an I/O error occurs
Returns:
CharacterSet object/**
     * Load the font details and metrics into the CharacterSetMetric object, this will use the
     * actual afp code page and character set files to load the object with the necessary metrics.
     *
     * @param characterSetName name of the characterset
     * @param codePageName name of the code page file
     * @param encoding encoding name
     * @param accessor used to load codepage and characterset
     * @param eventProducer for handling AFP related events
     * @return CharacterSet object
     * @throws IOException if an I/O error occurs
     */
    public CharacterSet buildSBCS(String characterSetName, String codePageName, String encoding,
            AFPResourceAccessor accessor, AFPEventProducer eventProducer) throws IOException {
        return processFont(characterSetName, codePageName, encoding, CharacterSetType.SINGLE_BYTE,
                accessor, eventProducer);
    }

    
Load the font details and metrics into the CharacterSetMetric object, this will use the
actual afp code page and character set files to load the object with the necessary metrics.
This method is to be used for double byte character sets (DBCS).
Params:
characterSetName – name of the characterset
codePageName – name of the code page file
encoding – encoding name
charsetType – the characterset type
accessor – used to load codepage and characterset
eventProducer – for handling AFP related events
Throws:
IOException – if an I/O error occurs
Returns:
CharacterSet object/**
     * Load the font details and metrics into the CharacterSetMetric object, this will use the
     * actual afp code page and character set files to load the object with the necessary metrics.
     * This method is to be used for double byte character sets (DBCS).
     *
     * @param characterSetName name of the characterset
     * @param codePageName name of the code page file
     * @param encoding encoding name
     * @param charsetType the characterset type
     * @param accessor used to load codepage and characterset
     * @param eventProducer for handling AFP related events
     * @return CharacterSet object
     * @throws IOException if an I/O error occurs
     */
    public CharacterSet buildDBCS(String characterSetName, String codePageName, String encoding,
            CharacterSetType charsetType, AFPResourceAccessor accessor, AFPEventProducer eventProducer)
            throws IOException {
        return processFont(characterSetName, codePageName, encoding, charsetType, accessor,
                eventProducer);
    }

    
Load the font details and metrics into the CharacterSetMetric object, this will use the
actual afp code page and character set files to load the object with the necessary metrics.
Params:
characterSetName – the CharacterSetMetric object to populate
codePageName – the name of the code page to use
encoding – name of the encoding in use
typeface – base14 font name
eventProducer – for handling AFP related events
Throws:
IOException – if an I/O error occurs
Returns:
CharacterSet object/**
     * Load the font details and metrics into the CharacterSetMetric object, this will use the
     * actual afp code page and character set files to load the object with the necessary metrics.
     *
     * @param characterSetName the CharacterSetMetric object to populate
     * @param codePageName the name of the code page to use
     * @param encoding name of the encoding in use
     * @param typeface base14 font name
     * @param eventProducer for handling AFP related events
     * @return CharacterSet object
     * @throws IOException if an I/O error occurs
     */
    public CharacterSet build(String characterSetName, String codePageName, String encoding,
            Typeface typeface, AFPEventProducer eventProducer) throws IOException {
        return new FopCharacterSet(codePageName, encoding, characterSetName, typeface,
                eventProducer);
    }

    public CharacterSet build(String characterSetName, String codePageName, String encoding,
                              Typeface typeface, AFPResourceAccessor accessor, AFPEventProducer eventProducer)
        throws IOException {
        return new FopCharacterSet(codePageName, encoding, characterSetName, typeface, accessor, eventProducer);
    }

    private CharacterSet processFont(String characterSetName, String codePageName, String encoding,
            CharacterSetType charsetType, AFPResourceAccessor accessor, AFPEventProducer eventProducer)
            throws IOException {
        // check for cached version of the characterset
        URI charSetURI = accessor.resolveURI(characterSetName);
        String cacheKey = charSetURI.toASCIIString() + "_" + characterSetName + "_" + codePageName;
        CharacterSet characterSet = (CharacterSet) characterSetsCache.get(cacheKey);
        if (characterSet != null) {
            return characterSet;
        }

        // characterset not in the cache, so recreating
        characterSet = new CharacterSet(codePageName, encoding, charsetType, characterSetName,
                accessor, eventProducer);

        InputStream inputStream = null;

        try {

            /**
             * Get the code page which contains the character mapping
             * information to map the unicode character id to the graphic
             * chracter global identifier.
             */
            Map<String, String> codePage;
            // TODO: This could have performance implications if several threads want to use the
            // codePagesCache to retrieve different codepages.
            synchronized (codePagesCache) {
                codePage = codePagesCache.get(codePageName);

                if (codePage == null) {
                    codePage = loadCodePage(codePageName, encoding, accessor, eventProducer);
                    codePagesCache.put(codePageName, codePage);
                }
            }

            inputStream = openInputStream(accessor, characterSetName, eventProducer);

            StructuredFieldReader structuredFieldReader = new StructuredFieldReader(inputStream);

            // Process D3A689 Font Descriptor
            FontDescriptor fontDescriptor = processFontDescriptor(structuredFieldReader);
            characterSet.setNominalVerticalSize(fontDescriptor.getNominalFontSizeInMillipoints());

            // Process D3A789 Font Control
            FontControl fontControl = processFontControl(structuredFieldReader);

            if (fontControl != null) {
                //process D3AE89 Font Orientation
                CharacterSetOrientation[] characterSetOrientations
                    = processFontOrientation(structuredFieldReader);

                double metricNormalizationFactor;
                if (fontControl.isRelative()) {
                    metricNormalizationFactor = 1;
                } else {
                    int dpi = fontControl.getDpi();
                    metricNormalizationFactor = 1000.0d * 72000.0d
                        / fontDescriptor.getNominalFontSizeInMillipoints() / dpi;
                }
                ValueNormalizer normalizer = new ValueNormalizer(metricNormalizationFactor);
                //process D3AC89 Font Position
                processFontPosition(structuredFieldReader, characterSetOrientations, normalizer);
                //process D38C89 Font Index (per orientation)
                for (CharacterSetOrientation characterSetOrientation : characterSetOrientations) {
                    processFontIndex(structuredFieldReader, characterSetOrientation, codePage, normalizer);
                    characterSet.addCharacterSetOrientation(characterSetOrientation);
                }
            } else {
                throw new IOException("Missing D3AE89 Font Control structured field.");
            }

        } finally {
            closeInputStream(inputStream);
        }
        characterSetsCache.put(cacheKey, characterSet);
        return characterSet;
    }

    private static class ValueNormalizer {

        private final double factor;

        public ValueNormalizer(double factor) {
            this.factor = factor;
        }

        public int normalize(int value) {
            return (int) Math.round(value *  factor);
        }
    }

    
Load the code page information from the appropriate file. The file name
to load is determined by the code page name and the file extension 'CDP'.
Params:
codePage – 
           the code page identifier
encoding – 
           the encoding to use for the character decoding
accessor – the resource accessor
eventProducer – for handling AFP related events
Throws:
IOException – if an I/O exception of some sort has occurred.
Returns:
a code page mapping (key: GCGID, value: Unicode character)/**
     * Load the code page information from the appropriate file. The file name
     * to load is determined by the code page name and the file extension 'CDP'.
     *
     * @param codePage
     *            the code page identifier
     * @param encoding
     *            the encoding to use for the character decoding
     * @param accessor the resource accessor
     * @param eventProducer for handling AFP related events
     * @return a code page mapping (key: GCGID, value: Unicode character)
     * @throws IOException if an I/O exception of some sort has occurred.
     */
    protected Map<String, String> loadCodePage(String codePage, String encoding,
            AFPResourceAccessor accessor, AFPEventProducer eventProducer) throws IOException {

        // Create the HashMap to store code page information
        Map<String, String> codePages = new HashMap<String, String>();

        InputStream inputStream = null;
        try {
            inputStream = openInputStream(accessor, codePage.trim(), eventProducer);
        } catch (IOException e) {
            eventProducer.codePageNotFound(this, e);
            throw e;
        }
        try {
            StructuredFieldReader structuredFieldReader = new StructuredFieldReader(inputStream);
            byte[] data = structuredFieldReader.getNext(CHARACTER_TABLE_SF);

            int position = 0;
            byte[] gcgiBytes = new byte[8];
            byte[] charBytes = new byte[1];

            // Read data, ignoring bytes 0 - 2
            for (int index = 3; index < data.length; index++) {
                if (position < 8) {
                    // Build the graphic character global identifier key
                    gcgiBytes[position] = data[index];
                    position++;
                } else if (position == 9) {
                    position = 0;
                    // Set the character
                    charBytes[0] = data[index];
                    String gcgiString = new String(gcgiBytes,
                            AFPConstants.EBCIDIC_ENCODING);
                    //Use the 8-bit char index to find the Unicode character using the Java encoding
                    //given in the configuration. If the code page and the Java encoding don't
                    //match, a wrong Unicode character will be associated with the AFP GCGID.
                    //Idea: we could use IBM's GCGID to Unicode map and build code pages ourselves.
                    String charString = new String(charBytes, encoding);
                    codePages.put(gcgiString, charString);
                } else {
                    position++;
                }
            }
        } finally {
            closeInputStream(inputStream);
        }

        return codePages;
    }

    
Process the font descriptor details using the structured field reader.
Params:
structuredFieldReader – the structured field reader
Throws:
IOException – if an I/O exception of some sort has occurred.
Returns:
a class representing the font descriptor/**
     * Process the font descriptor details using the structured field reader.
     *
     * @param structuredFieldReader the structured field reader
     * @return a class representing the font descriptor
     * @throws IOException if an I/O exception of some sort has occurred.
     */
    private static FontDescriptor processFontDescriptor(
            StructuredFieldReader structuredFieldReader) throws IOException {

        byte[] fndData = structuredFieldReader.getNext(FONT_DESCRIPTOR_SF);
        return new FontDescriptor(fndData);
    }

    
Process the font control details using the structured field reader.
Params:
structuredFieldReader – 
           the structured field reader
Throws:
IOException – if an I/O exception of some sort has occurred.
Returns:
the FontControl/**
     * Process the font control details using the structured field reader.
     *
     * @param structuredFieldReader
     *            the structured field reader
     * @return the FontControl
     * @throws IOException if an I/O exception of some sort has occurred.
     */
    private FontControl processFontControl(StructuredFieldReader structuredFieldReader)
            throws IOException {

        byte[] fncData = structuredFieldReader.getNext(FONT_CONTROL_SF);

        FontControl fontControl = null;
        if (fncData != null) {
            fontControl = new FontControl();

            if (fncData[7] == (byte) 0x02) {
                fontControl.setRelative(true);
            }
            int metricResolution = getUBIN(fncData, 9);
            if (metricResolution == 1000) {
                //Special case: 1000 units per em (rather than dpi)
                fontControl.setUnitsPerEm(1000);
            } else {
                fontControl.setDpi(metricResolution / 10);
            }
        }
        return fontControl;
    }

    
Process the font orientation details from using the structured field
reader.
Params:
structuredFieldReader – 
           the structured field reader
Throws:
IOException – if an I/O exception of some sort has occurred.
Returns:
CharacterSetOrientation array/**
     * Process the font orientation details from using the structured field
     * reader.
     *
     * @param structuredFieldReader
     *            the structured field reader
     * @return CharacterSetOrientation array
     * @throws IOException if an I/O exception of some sort has occurred.
     */
    private CharacterSetOrientation[] processFontOrientation(
        StructuredFieldReader structuredFieldReader) throws IOException {

        byte[] data = structuredFieldReader.getNext(FONT_ORIENTATION_SF);

        int position = 0;
        byte[] fnoData = new byte[26];

        List<CharacterSetOrientation> orientations = new ArrayList<CharacterSetOrientation>();

        // Read data, ignoring bytes 0 - 2
        for (int index = 3; index < data.length; index++) {
            // Build the font orientation record
            fnoData[position] = data[index];
            position++;

            if (position == 26) {
                position = 0;

                int orientation = determineOrientation(fnoData[2]);
                int spaceIncrement = getUBIN(fnoData, 8);
                int emIncrement = getUBIN(fnoData, 14);
                int nominalCharacterIncrement = getUBIN(fnoData, 20);

                orientations.add(new CharacterSetOrientation(orientation, spaceIncrement,
                        emIncrement, nominalCharacterIncrement));
            }
        }
        return orientations.toArray(EMPTY_CSO_ARRAY);
    }

    
Populate the CharacterSetOrientation object in the suplied array with the
font position details using the supplied structured field reader.
Params:
structuredFieldReader – 
           the structured field reader
characterSetOrientations – 
           the array of CharacterSetOrientation objects
metricNormalizationFactor – factor to apply to the metrics to get normalized
                 font metric values
Throws:
IOException – if an I/O exception of some sort has occurred./**
     * Populate the CharacterSetOrientation object in the suplied array with the
     * font position details using the supplied structured field reader.
     *
     * @param structuredFieldReader
     *            the structured field reader
     * @param characterSetOrientations
     *            the array of CharacterSetOrientation objects
     * @param metricNormalizationFactor factor to apply to the metrics to get normalized
     *                  font metric values
     * @throws IOException if an I/O exception of some sort has occurred.
     */
    private void processFontPosition(StructuredFieldReader structuredFieldReader,
        CharacterSetOrientation[] characterSetOrientations, ValueNormalizer normalizer)
            throws IOException {

        byte[] data = structuredFieldReader.getNext(FONT_POSITION_SF);

        int position = 0;
        byte[] fpData = new byte[26];

        int characterSetOrientationIndex = 0;

        // Read data, ignoring bytes 0 - 2
        for (int index = 3; index < data.length; index++) {
            if (position < 22) {
                // Build the font orientation record
                fpData[position] = data[index];
                if (position == 9) {
                    CharacterSetOrientation characterSetOrientation
                            = characterSetOrientations[characterSetOrientationIndex];
                    int xHeight = getSBIN(fpData, 2);
                    int capHeight = getSBIN(fpData, 4);
                    int ascHeight = getSBIN(fpData, 6);
                    int dscHeight = getSBIN(fpData, 8);
                    dscHeight = dscHeight * -1;
                    int underscoreWidth = getUBIN(fpData, 17);
                    int underscorePosition = getSBIN(fpData, 20);
                    characterSetOrientation.setXHeight(normalizer.normalize(xHeight));
                    characterSetOrientation.setCapHeight(normalizer.normalize(capHeight));
                    characterSetOrientation.setAscender(normalizer.normalize(ascHeight));
                    characterSetOrientation.setDescender(normalizer.normalize(dscHeight));
                    characterSetOrientation.setUnderscoreWidth(normalizer.normalize(underscoreWidth));
                    characterSetOrientation.setUnderscorePosition(normalizer.normalize(underscorePosition));
                }
            } else if (position == 22) {
                position = 0;
                characterSetOrientationIndex++;
                fpData[position] = data[index];
            }
            position++;
        }

    }


    private void processFontIndex(StructuredFieldReader structuredFieldReader, CharacterSetOrientation cso,
            Map<String, String> codepage, ValueNormalizer normalizer)
            throws IOException {

        byte[] data = structuredFieldReader.getNext(FONT_INDEX_SF);

        int position = 0;

        byte[] gcgid = new byte[8];
        byte[] fiData = new byte[20];

        String firstABCMismatch = null;

        // Read data, ignoring bytes 0 - 2
        for (int index = 3; index < data.length; index++) {
            if (position < 8) {
                gcgid[position] = data[index];
                position++;
            } else if (position < 27) {
                fiData[position - 8] = data[index];
                position++;
            } else if (position == 27) {

                fiData[position - 8] = data[index];

                position = 0;

                String gcgiString = new String(gcgid, AFPConstants.EBCIDIC_ENCODING);

                String idx = codepage.get(gcgiString);

                if (idx != null) {

                    char cidx = idx.charAt(0);
                    int width = getUBIN(fiData, 0);
                    int ascendHt = getSBIN(fiData, 2);
                    int descendDp = getSBIN(fiData, 4);
                    int a = getSBIN(fiData, 10);
                    int b = getUBIN(fiData, 12);
                    int c = getSBIN(fiData, 14);
                    int abc = a + b + c;
                    int diff = Math.abs(abc - width);
                    if (diff != 0 && width != 0) {
                        double diffPercent = 100 * diff / (double) width;
                        if (diffPercent > 2) {
                            if (LOG.isTraceEnabled()) {
                                LOG.trace(gcgiString + ": "
                                        + a + " + " + b + " + " + c + " = " + (a + b + c)
                                        + " but found: " + width);
                            }
                            if (firstABCMismatch == null) {
                                firstABCMismatch = gcgiString;
                            }
                        }
                    }
                    int normalizedWidth = normalizer.normalize(width);
                    int x0 = normalizer.normalize(a);
                    int y0 = normalizer.normalize(-descendDp);
                    int dx = normalizer.normalize(b);
                    int dy = normalizer.normalize(ascendHt + descendDp);
                    cso.setCharacterMetrics(cidx, normalizedWidth, new Rectangle(x0, y0, dx, dy));
                }
            }
        }

        if (LOG.isDebugEnabled() && firstABCMismatch != null) {
            //Debug level because it usually is no problem.
            LOG.debug("Font has metrics inconsitencies where A+B+C doesn't equal the"
                    + " character increment. The first such character found: "
                    + firstABCMismatch);
        }
    }

    private static int getUBIN(byte[] data, int start) {
        return ((data[start] & 0xFF) << 8) + (data[start + 1] & 0xFF);
    }

    private static int getSBIN(byte[] data, int start) {
        int ubin = ((data[start] & 0xFF) << 8) + (data[start + 1] & 0xFF);
        if ((ubin & 0x8000) != 0) {
            //extend sign
            return ubin | 0xFFFF0000;
        } else {
            return ubin;
        }
    }

    private class FontControl {

        private int dpi;
        private int unitsPerEm;

        private boolean isRelative;

        public int getDpi() {
            return dpi;
        }

        public void setDpi(int i) {
            dpi = i;
        }

        public int getUnitsPerEm() {
            return this.unitsPerEm;
        }

        public void setUnitsPerEm(int value) {
            this.unitsPerEm = value;
        }

        public boolean isRelative() {
            return isRelative;
        }

        public void setRelative(boolean b) {
            isRelative = b;
        }
    }

    private static class FontDescriptor {

        private byte[] data;

        public FontDescriptor(byte[] data) {
            this.data = data;
        }

        public int getNominalFontSizeInMillipoints() {
            int nominalFontSize = 100 * getUBIN(data, 39);
            return nominalFontSize;
        }
    }

    private static final class SingleByteLoader extends CharacterSetBuilder {

        private static final SingleByteLoader INSTANCE = new SingleByteLoader();

        private SingleByteLoader() {
            super();
        }

        private static SingleByteLoader getInstance() {
            return INSTANCE;
        }
    }

    
Double-byte (CID Keyed font (Type 0)) implementation of AFPFontReader.
/**
     * Double-byte (CID Keyed font (Type 0)) implementation of AFPFontReader.
     */
    private static final class DoubleByteLoader extends CharacterSetBuilder {

        private static final DoubleByteLoader INSTANCE = new DoubleByteLoader();

        private DoubleByteLoader() {
        }

        static DoubleByteLoader getInstance() {
            return INSTANCE;
        }

        @Override
        protected Map<String, String> loadCodePage(String codePage, String encoding,
                AFPResourceAccessor accessor, AFPEventProducer eventProducer) throws IOException {
            // Create the HashMap to store code page information
            Map<String, String> codePages = new HashMap<String, String>();
            InputStream inputStream = null;
            try {
                inputStream = super.openInputStream(accessor, codePage.trim(), eventProducer);
            } catch (IOException e) {
                eventProducer.codePageNotFound(this, e);
                throw e;
            }
            try {
                StructuredFieldReader structuredFieldReader = new StructuredFieldReader(inputStream);
                byte[] data;
                while ((data = structuredFieldReader.getNext(CHARACTER_TABLE_SF)) != null) {
                    int position = 0;
                    byte[] gcgiBytes = new byte[8];
                    byte[] charBytes = new byte[2];
                    // Read data, ignoring bytes 0 - 2
                    for (int index = 3; index < data.length; index++) {

                        if (position < 8) {
                            // Build the graphic character global identifier key
                            gcgiBytes[position] = data[index];
                            position++;
                        } else if (position == 9) {
                            // Set the character
                            charBytes[0] = data[index];
                            position++;
                        } else if (position == 10) {
                            position = 0;
                            // Set the character
                            charBytes[1] = data[index];

                            String gcgiString = new String(gcgiBytes,
                                    AFPConstants.EBCIDIC_ENCODING);
                            String charString = new String(charBytes, encoding);
                            codePages.put(gcgiString, charString);
                        } else {
                            position++;
                        }
                    }
                }
            } finally {
                super.closeInputStream(inputStream);
            }
            return codePages;
        }

    }

    private static int determineOrientation(byte orientation) {
        int degrees = 0;

        switch (orientation) {
        case 0x00:
            degrees = 0;
            break;
        case 0x2D:
            degrees = 90;
            break;
        case 0x5A:
            degrees = 180;
            break;
        case (byte) 0x87:
            degrees = 270;
            break;
        default:
            throw new IllegalStateException("Invalid orientation: " + orientation);
        }
        return degrees;
    }
}