org.jpedal.fonts.objects.FontData Maven / Gradle / Ivy

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/*
 * ===========================================
 * Java Pdf Extraction Decoding Access Library
 * ===========================================
 *
 * Project Info:  http://www.idrsolutions.com
 * Help section for developers at http://www.idrsolutions.com/support/
 *
 * (C) Copyright 1997-2017 IDRsolutions and Contributors.
 *
 * This file is part of JPedal/JPDF2HTML5
 *
 @LICENSE@
 *
 * ---------------
 * FontData.java
 * ---------------
 */
package org.jpedal.fonts.objects;

import java.io.IOException;
import java.io.RandomAccessFile;

import org.jpedal.utils.LogWriter;

/**
 * provides access to font data and caches large objects
 */
public class FontData {

    private byte[] fontData;

    /**
     * flag to show if all fontData in memory or just some
     */
    private boolean isInMemory;

    /**
     * real size of font object
     */
    private int fullLength;

    /**
     * offset to actual block loaded
     */
    private int offset;

    /**
     * bytes size of font we keep in memory
     */
    public static int maxSizeAllowedInMemory = -1;

    /**
     * max size of data kept in memory at any one point
     */
    private int blockSize = 8192;

    private RandomAccessFile fontFile;

    /**
     * pass in name of temp file on disk so we can just read part at a time -
     * if not part of PDF user is responsible for deleting
     *
     * @param cachedFile
     */
    public FontData(final String cachedFile) { //, byte[] stream) {

        try {
            fontFile = new RandomAccessFile(cachedFile, "r");
            fullLength = (int) fontFile.length();

        } catch (final Exception e) {
            LogWriter.writeLog("Exception: " + e.getMessage());
        }

        //if small read all
        if (fullLength < maxSizeAllowedInMemory) {

            blockSize = maxSizeAllowedInMemory;

            adjustForCache(0);

            isInMemory = true;

        }
    }

    public byte getByte(int pointer) {

        if (!isInMemory) {
            pointer = adjustForCache(pointer);
        }

        // System.err.println("Now="+pointer+" "+fontData.length+" inMemory="+isInMemory);

        if (pointer >= fontData.length) {
            return 0;
        } else {
            return fontData[pointer];
        }
    }

    /**
     * check block in memory, read if not and
     * adjust pointer
     *
     * @param pointer
     * @return
     */
    private int adjustForCache(final int pointer) {

        //see if in memory and load if not
        if (fontData == null || pointer < offset || pointer >= (offset + blockSize - 1)) {

            try {

                fontFile.seek(pointer);
                fontData = new byte[blockSize];

                fontFile.read(fontData);

            } catch (final IOException e) {
                LogWriter.writeLog("Exception: " + e.getMessage());
            }

            offset = pointer;

        }

        //subtract offset to make it fall in loaded range
        return pointer - offset;
    }

    private int adjustForCache(final int pointer, final int blockSize) {

        //see if in memory and load if not
        //if(fontData==null || pointer=(offset+blockSize-1)){

        try {

            fontFile.seek(pointer);
            fontData = new byte[blockSize];

            fontFile.read(fontData);

        } catch (final IOException e) {
            LogWriter.writeLog("Exception: " + e.getMessage());
        }
        offset = pointer;

        //}

        //subtract offset to make it fall in loaded range
        return pointer - offset;
    }

    public byte[] getBytes(int startPointer, final int length) {

        if (!isInMemory) {
            startPointer = adjustForCache(startPointer, length + 1);
        }

        final byte[] block = new byte[length];
        System.arraycopy(fontData, startPointer, block, 0, length);
        return block;

    }

    /**
     * total length of FontData in bytes
     */
    public int length() {

        if (isInMemory) {
            return fontData.length;
        } else {
            return fullLength;
        }
    }

    public void close() {
        if (fontFile != null) {
            try {
                fontFile.close();
            } catch (final IOException e) {
                LogWriter.writeLog("Exception: " + e.getMessage());
            }
        }
    }
}