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/* 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 org.brotli.dec;
/**
* Contains a collection of huffman trees with the same alphabet size.
*/
final class HuffmanTreeGroup {
/**
* The maximal alphabet size in this group.
*/
private int alphabetSize;
/**
* Storage for Huffman lookup tables.
*/
int[] codes;
/**
* Offsets of distinct lookup tables in {@link #codes} storage.
*/
int[] trees;
/**
* Initializes the Huffman tree group.
*
* @param group POJO to be initialised
* @param alphabetSize the maximal alphabet size in this group
* @param n number of Huffman codes
*/
static void init(HuffmanTreeGroup group, int alphabetSize, int n) {
group.alphabetSize = alphabetSize;
group.codes = new int[n * Huffman.HUFFMAN_MAX_TABLE_SIZE];
group.trees = new int[n];
}
/**
* Decodes Huffman trees from input stream and constructs lookup tables.
*
* @param group target POJO
* @param br data source
*/
static void decode(HuffmanTreeGroup group, BitReader br) {
int next = 0;
int n = group.trees.length;
for (int i = 0; i < n; i++) {
group.trees[i] = next;
Decode.readHuffmanCode(group.alphabetSize, group.codes, next, br);
next += Huffman.HUFFMAN_MAX_TABLE_SIZE;
}
}
}
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