/*
 * DSI utilities
 *
 * Copyright (C) 2010-2020 Sebastiano Vigna
 *
 *  This library is free software; you can redistribute it and/or modify it
 *  under the terms of the GNU Lesser General Public License as published by the Free
 *  Software Foundation; either version 3 of the License, or (at your option)
 *  any later version.
 *
 *  This library is distributed in the hope that it will be useful, but
 *  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
 *  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser General Public License
 *  for more details.
 *
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with this program; if not, see <http://www.gnu.org/licenses/>.
 *
 */

package it.unimi.dsi.compression;

import static org.junit.Assert.assertEquals;

import java.io.IOException;
import java.util.Random;

import it.unimi.dsi.bits.BitVector;
import it.unimi.dsi.fastutil.booleans.BooleanArrayList;
import it.unimi.dsi.fastutil.booleans.BooleanIterator;
import it.unimi.dsi.fastutil.io.FastByteArrayOutputStream;
import it.unimi.dsi.io.InputBitStream;
import it.unimi.dsi.io.OutputBitStream;

public abstract class CodecTestCase {
	protected static void checkPrefixCodec(final PrefixCodec codec, final Random r) throws IOException {
		final int[] symbol = new int[100];
		final BooleanArrayList bits = new BooleanArrayList();
		for(int i = 0; i < symbol.length; i++) symbol[i] = r.nextInt(codec.size());
		for (final int element : symbol) {
			final BitVector word = codec.codeWords()[element];
			for(long j = 0; j < word.length(); j++) bits.add(word.getBoolean(j));
		}

		final BooleanIterator booleanIterator = bits.iterator();
		final Decoder decoder = codec.decoder();
		for (final int element : symbol) {
			assertEquals(element, decoder.decode(booleanIterator));
		}

		final FastByteArrayOutputStream fbaos = new FastByteArrayOutputStream();
		@SuppressWarnings("resource")
		final
		OutputBitStream obs = new OutputBitStream(fbaos, 0);
		obs.write(bits.iterator());
		obs.flush();
		final InputBitStream ibs = new InputBitStream(fbaos.array);

		for (final int element : symbol) {
			assertEquals(element, decoder.decode(ibs));
		}
	}

	protected void checkLengths(final int[] frequency, final int[] codeLength, final BitVector[] codeWord) {
		for(int i = 0; i < frequency.length; i++)
			assertEquals(Integer.toString(i), codeLength[i], codeWord[i].length());
	}
}