com.itextpdf.io.codec.brotli.dec.Dictionary Maven / Gradle / Ivy
/* Copyright 2015 Google Inc. All Rights Reserved.
Distributed under MIT license.
See file LICENSE for detail or copy at https://opensource.org/licenses/MIT
*/
package com.itextpdf.io.codec.brotli.dec;
import java.nio.ByteBuffer;
/**
* Collection of static dictionary words.
*
* Dictionary content is loaded from binary resource when {@link #getData()} is executed for the
* first time. Consequently, it saves memory and CPU in case dictionary is not required.
*
*
One possible drawback is that multiple threads that need dictionary data may be blocked (only
* once in each classworld). To avoid this, it is enough to call {@link #getData()} proactively.
*/
public final class Dictionary {
private static volatile ByteBuffer data;
private static class DataLoader {
static final boolean OK;
static {
boolean ok = true;
try {
Class.forName(Dictionary.class.getPackage().getName() + ".DictionaryData");
} catch (Throwable ex) {
ok = false;
}
OK = ok;
}
}
public static void setData(ByteBuffer data) {
Dictionary.data = data;
}
public static ByteBuffer getData() {
if (data != null) {
return data;
}
if (!DataLoader.OK) {
throw new BrotliRuntimeException("brotli dictionary is not set");
}
/* Might have been set when {@link DictionaryData} was loaded.*/
return data;
}
static final int[] OFFSETS_BY_LENGTH = {
0, 0, 0, 0, 0, 4096, 9216, 21504, 35840, 44032, 53248, 63488, 74752, 87040, 93696, 100864,
104704, 106752, 108928, 113536, 115968, 118528, 119872, 121280, 122016
};
static final int[] SIZE_BITS_BY_LENGTH = {
0, 0, 0, 0, 10, 10, 11, 11, 10, 10, 10, 10, 10, 9, 9, 8, 7, 7, 8, 7, 7, 6, 6, 5, 5
};
static final int MIN_WORD_LENGTH = 4;
static final int MAX_WORD_LENGTH = 24;
static final int MAX_TRANSFORMED_WORD_LENGTH = 5 + MAX_WORD_LENGTH + 8;
}