/* ====================================================================
   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.
==================================================================== */

package org.apache.poi.util;

import junit.framework.TestCase;
import org.apache.poi.util.LittleEndian.BufferUnderrunException;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStream;

/**
 * Class to test LittleEndian functionality
 *
 * @author Marc Johnson
 */
public final class TestLittleEndian extends TestCase {

    /**
     * test the getShort() method
     */
    public void testGetShort() {
        byte[] testdata = new byte[ LittleEndian.SHORT_SIZE + 1 ];

        testdata[0] = 0x01;
        testdata[1] = (byte) 0xFF;
        testdata[2] = 0x02;
        short expected[] = new short[2];

        expected[0] = ( short ) 0xFF01;
        expected[1] = 0x02FF;
        assertEquals(expected[0], LittleEndian.getShort(testdata));
        assertEquals(expected[1], LittleEndian.getShort(testdata, 1));
    }

    public void testGetUShort() {
        byte[] testdata = {
            (byte) 0x01,
            (byte) 0xFF,
            (byte) 0x02,
        };
        byte[] testdata2 = {
            (byte) 0x0D,
            (byte) 0x93,
            (byte) 0xFF,
        };

        int expected0 = 0xFF01;
        int expected1 = 0x02FF;
        int expected2 = 0x930D;
        int expected3 = 0xFF93;
        assertEquals(expected0, LittleEndian.getUShort(testdata));
        assertEquals(expected1, LittleEndian.getUShort(testdata, 1));
        assertEquals(expected2, LittleEndian.getUShort(testdata2));
        assertEquals(expected3, LittleEndian.getUShort(testdata2, 1));

        byte[] testdata3 = new byte[ LittleEndian.SHORT_SIZE + 1 ];
        LittleEndian.putUShort(testdata3, 0, expected2);
        LittleEndian.putUShort(testdata3, 1, expected3);
        assertEquals(testdata3[0], 0x0D);
        assertEquals(testdata3[1], (byte)0x93);
        assertEquals(testdata3[2], (byte)0xFF);
        assertEquals(expected2, LittleEndian.getUShort(testdata3));
        assertEquals(expected3, LittleEndian.getUShort(testdata3, 1));
        
    }

    private static final byte[]   _double_array =
    {
        56, 50, -113, -4, -63, -64, -13, 63, 76, -32, -42, -35, 60, -43, 3, 64
    };
	/** 0x7ff8000000000000 encoded in little endian order */
	private static final byte[] _nan_double_array = HexRead.readFromString("00 00 00 00 00 00 F8 7F");
    private static final double[] _doubles      =
    {
        1.23456, 2.47912, Double.NaN
    };

    /**
     * test the getDouble() method
     */
    public void testGetDouble() {
        assertEquals(_doubles[0], LittleEndian.getDouble(_double_array, 0), 0.000001 );
        assertEquals(_doubles[1], LittleEndian.getDouble( _double_array, LittleEndian.DOUBLE_SIZE), 0.000001);
        assertTrue(Double.isNaN(LittleEndian.getDouble(_nan_double_array, 0)));

        double nan = LittleEndian.getDouble(_nan_double_array, 0);
        byte[] data = new byte[8];
        LittleEndian.putDouble(data, 0, nan);
        for ( int i = 0; i < data.length; i++ ) {
            assertEquals(data[i], _nan_double_array[i]);
        }
    }

    /**
     * test the getInt() method
     */
    public void testGetInt() {
        // reading 4 byte data from a 5 byte buffer
        byte[] testdata = {
                (byte) 0x01,
                (byte) 0xFF,
                (byte) 0xFF,
                (byte) 0xFF,
                (byte) 0x02,
        };

        assertEquals(0xFFFFFF01, LittleEndian.getInt(testdata));
        assertEquals(0x02FFFFFF, LittleEndian.getInt(testdata, 1));
    }

    /**
     * test the getLong method
     */
    public void testGetLong() {

        // reading 8 byte values from a 9 byte buffer
        byte[] testdata = {
            (byte) 0x01,
            (byte) 0xFF,
            (byte) 0xFF,
            (byte) 0xFF,
            (byte) 0xFF,
            (byte) 0xFF,
            (byte) 0xFF,
            (byte) 0xFF,
            (byte) 0x02,
        };

        assertEquals(0xFFFFFFFFFFFFFF01L, LittleEndian.getLong(testdata, 0));
        assertEquals(0x02FFFFFFFFFFFFFFL, LittleEndian.getLong(testdata, 1));
    }

    /**
     * test the PutShort method
     */
    public void testPutShort() {
        byte[] expected = new byte[ LittleEndian.SHORT_SIZE + 1 ];

        expected[0] = 0x01;
        expected[1] = (byte) 0xFF;
        expected[2] = 0x02;
        byte[] received   = new byte[ LittleEndian.SHORT_SIZE + 1 ];
        short  testdata[] = new short[2];

        testdata[0] = ( short ) 0xFF01;
        testdata[1] = 0x02FF;
        LittleEndian.putShort(received, testdata[0]);
        assertTrue(compareByteArrays(received, expected, 0, LittleEndian.SHORT_SIZE));
        LittleEndian.putShort(received, 1, testdata[1]);
        assertTrue(compareByteArrays(received, expected, 1, LittleEndian.SHORT_SIZE));
    }

    /**
     * test the putInt method
     */
    public void testPutInt() {
        // writing 4 byte data to a 5 byte buffer
        byte[] expected = {
                (byte) 0x01,
                (byte) 0xFF,
                (byte) 0xFF,
                (byte) 0xFF,
                (byte) 0x02,
        };
        byte[] received = new byte[ LittleEndian.INT_SIZE + 1 ];

        LittleEndian.putInt(received, 0xFFFFFF01);
        assertTrue(compareByteArrays(received, expected, 0, LittleEndian.INT_SIZE));
        LittleEndian.putInt(received, 1, 0x02FFFFFF);
        assertTrue(compareByteArrays(received, expected, 1, LittleEndian.INT_SIZE));
    }

    /**
     * test the putDouble methods
     */
    public void testPutDouble() {
        byte[] received = new byte[ LittleEndian.DOUBLE_SIZE + 1 ];

        LittleEndian.putDouble(received, 0, _doubles[0]);
        assertTrue(compareByteArrays(received, _double_array, 0, LittleEndian.DOUBLE_SIZE));
        LittleEndian.putDouble(received, 1, _doubles[1]);
        byte[] expected = new byte[ LittleEndian.DOUBLE_SIZE + 1 ];

        System.arraycopy(_double_array, LittleEndian.DOUBLE_SIZE, expected,
                         1, LittleEndian.DOUBLE_SIZE);
        assertTrue(compareByteArrays(received, expected, 1, LittleEndian.DOUBLE_SIZE));
    }

    /**
     * test the putLong method
     */
    public void testPutLong() {
        // writing 8 byte values to a 9 byte buffer
        byte[] expected = {
            (byte) 0x01,
            (byte) 0xFF,
            (byte) 0xFF,
            (byte) 0xFF,
            (byte) 0xFF,
            (byte) 0xFF,
            (byte) 0xFF,
            (byte) 0xFF,
            (byte) 0x02,
        };
        byte[] received   = new byte[ LittleEndian.LONG_SIZE + 1 ];

        long testdata0 = 0xFFFFFFFFFFFFFF01L;
        long testdata1 = 0x02FFFFFFFFFFFFFFL;
        LittleEndian.putLong(received, 0, testdata0);
        assertTrue(compareByteArrays(received, expected, 0, LittleEndian.LONG_SIZE));
        LittleEndian.putLong(received, 1, testdata1);
        assertTrue(compareByteArrays(received, expected, 1, LittleEndian.LONG_SIZE));
    }

    private static byte[] _good_array = {
        0x01, 0x02, 0x01, 0x02, 
        0x01, 0x02, 0x01, 0x02, 
        0x01, 0x02, 0x01, 0x02,
        0x01, 0x02, 0x01, 0x02,
    };
    private static byte[] _bad_array  = {
        0x01
    };

    /**
     * test the readShort method
     */
    public void testReadShort() throws IOException {
        short       expected_value = 0x0201;
        InputStream stream         = new ByteArrayInputStream(_good_array);
        int         count          = 0;

        while (stream.available() > 0) {
            short value = LittleEndian.readShort(stream);
            assertEquals(value, expected_value);
            count++;
        }
        assertEquals(count,
                     _good_array.length / LittleEndianConsts.SHORT_SIZE);
        stream = new ByteArrayInputStream(_bad_array);
        try {
            LittleEndian.readShort(stream);
            fail("Should have caught BufferUnderrunException");
        } catch (BufferUnderrunException ignored) {
            // as expected
        }
    }

    /**
     * test the readInt method
     */
    public void testReadInt() throws IOException {
        int         expected_value = 0x02010201;
        InputStream stream         = new ByteArrayInputStream(_good_array);
        int         count          = 0;

        while (stream.available() > 0) {
            int value = LittleEndian.readInt(stream);
            assertEquals(value, expected_value);
            count++;
        }
        assertEquals(count, _good_array.length / LittleEndianConsts.INT_SIZE);
        stream = new ByteArrayInputStream(_bad_array);
        try {
            LittleEndian.readInt(stream);
            fail("Should have caught BufferUnderrunException");
        } catch (BufferUnderrunException ignored) {

            // as expected
        }
    }

    /**
     * test the readLong method
     */
    public void testReadLong() throws IOException {
        long        expected_value = 0x0201020102010201L;
        InputStream stream         = new ByteArrayInputStream(_good_array);
        int         count          = 0;

        while (stream.available() > 0) {
            long value = LittleEndian.readLong(stream);
            assertEquals(value, expected_value);
            count++;
        }
        assertEquals(count,
                     _good_array.length / LittleEndianConsts.LONG_SIZE);
        stream = new ByteArrayInputStream(_bad_array);
        try {
            LittleEndian.readLong(stream);
            fail("Should have caught BufferUnderrunException");
        } catch (BufferUnderrunException ignored) {
            // as expected
        }
    }

//    public void testReadFromStream() throws IOException {
//        int actual;
//        actual = LittleEndian.readUShort(new ByteArrayInputStream(new byte[] { 5, -128, }));
//        assertEquals(32773, actual);
//        
//        actual = LittleEndian.readUShort(new ByteArrayInputStream(new byte[] { 1, 2, 3, 4, }));
//        assertEquals(513, actual);
//
//        try {
//            LittleEndian.readInt(new ByteArrayInputStream(new byte[] { 1, 2, 3, }));
//            fail("Should have caught BufferUnderrunException");
//        } catch (BufferUnderrunException ignored) {
//            // as expected
//        }
//    }

    public void testUnsignedByteToInt() {
        assertEquals(255, LittleEndian.ubyteToInt((byte)255));
    }

    private static boolean compareByteArrays(byte [] received, byte [] expected,
                                  int offset, int size) {

        for (int j = offset; j < offset + size; j++) {
            if (received[j] != expected[j]) {
                System.out.println("difference at index " + j);
                return false;
            }
        }
        return true;
    }

    public void testUnsignedShort() {
        assertEquals(0xffff, LittleEndian.getUShort(new byte[] { (byte)0xff, (byte)0xff }, 0));
    }
}