countinginputstreamtest.java

java 的io 操作类 java 的io 操作类

/*
 * 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.commons.io.input;

import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.OutputStream;

import junit.framework.TestCase;

import org.apache.commons.io.IOUtils;
import org.apache.commons.io.output.NullOutputStream;

/**
 * Tests the CountingInputStream.
 *
 * @author Marcelo Liberato
 * @author Stephen Colebourne
 * @version $Id: CountingInputStreamTest.java 606381 2007-12-22 02:03:16Z ggregory $
 */
public class CountingInputStreamTest extends TestCase {

    public CountingInputStreamTest(String name) {
        super(name);
    }

    public void testCounting() throws Exception {
        String text = "A piece of text";
        byte[] bytes = text.getBytes();
        ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
        CountingInputStream cis = new CountingInputStream(bais);

        // have to declare this larger as we're going to read 
        // off the end of the stream and input stream seems 
        // to do bounds checking
        byte[] result = new byte[21];

        byte[] ba = new byte[5];
        int found = cis.read(ba);
        System.arraycopy(ba, 0, result, 0, 5);
        assertEquals( found, cis.getCount() );

        int value = cis.read();
        found++; 
        result[5] = (byte)value;
        assertEquals( found, cis.getCount() );

        found += cis.read(result, 6, 5);
        assertEquals( found, cis.getCount() );

        found += cis.read(result, 11, 10); // off the end
        assertEquals( found, cis.getCount() );

        // trim to get rid of the 6 empty values
        String textResult = new String(result).trim();
        assertEquals(textResult, text);
    }


    /**
     * Test for files > 2GB in size - see issue IO-84
     */
    public void testLargeFiles_IO84() throws Exception {
        long size = (long)Integer.MAX_VALUE + (long)1;
        NullInputStream mock    = new NullInputStream(size);
        CountingInputStream cis = new CountingInputStream(mock);
        OutputStream out        = new NullOutputStream();

        // Test integer methods
        IOUtils.copyLarge(cis, out);
        try {
            cis.getCount();
            fail("Expected getCount() to throw an ArithmeticException");
        } catch (ArithmeticException ae) {
            // expected result
        }
        try {
            cis.resetCount();
            fail("Expected resetCount() to throw an ArithmeticException");
        } catch (ArithmeticException ae) {
            // expected result
        }

        mock.close();

        // Test long methods
        IOUtils.copyLarge(cis, out);
        assertEquals("getByteCount()",   size, cis.getByteCount());
        assertEquals("resetByteCount()", size, cis.resetByteCount());
    }

    public void testResetting() throws Exception {
        String text = "A piece of text";
        byte[] bytes = text.getBytes();
        ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
        CountingInputStream cis = new CountingInputStream(bais);

        byte[] result = new byte[bytes.length];

        int found = cis.read(result, 0, 5);
        assertEquals( found, cis.getCount() );

        int count = cis.resetCount();
        found = cis.read(result, 6, 5);
        assertEquals( found, count );
    }
    
    public void testZeroLength1() throws Exception {
        ByteArrayInputStream bais = new ByteArrayInputStream(new byte[0]);
        CountingInputStream cis = new CountingInputStream(bais);

        int found = cis.read();
        assertEquals(-1, found);
        assertEquals(0, cis.getCount());
    }

    public void testZeroLength2() throws Exception {
        ByteArrayInputStream bais = new ByteArrayInputStream(new byte[0]);
        CountingInputStream cis = new CountingInputStream(bais);

        byte[] result = new byte[10];

        int found = cis.read(result);
        assertEquals(-1, found);
        assertEquals(0, cis.getCount());
    }

    public void testZeroLength3() throws Exception {
        ByteArrayInputStream bais = new ByteArrayInputStream(new byte[0]);
        CountingInputStream cis = new CountingInputStream(bais);

        byte[] result = new byte[10];

        int found = cis.read(result, 0, 5);
        assertEquals(-1, found);
        assertEquals(0, cis.getCount());
    }

    public void testEOF1() throws Exception {
        ByteArrayInputStream bais = new ByteArrayInputStream(new byte[2]);
        CountingInputStream cis = new CountingInputStream(bais);

        int found = cis.read();
        assertEquals(0, found);
        assertEquals(1, cis.getCount());
        found = cis.read();
        assertEquals(0, found);
        assertEquals(2, cis.getCount());
        found = cis.read();
        assertEquals(-1, found);
        assertEquals(2, cis.getCount());
    }

    public void testEOF2() throws Exception {
        ByteArrayInputStream bais = new ByteArrayInputStream(new byte[2]);
        CountingInputStream cis = new CountingInputStream(bais);

        byte[] result = new byte[10];

        int found = cis.read(result);
        assertEquals(2, found);
        assertEquals(2, cis.getCount());
    }

    public void testEOF3() throws Exception {
        ByteArrayInputStream bais = new ByteArrayInputStream(new byte[2]);
        CountingInputStream cis = new CountingInputStream(bais);

        byte[] result = new byte[10];

        int found = cis.read(result, 0, 5);
        assertEquals(2, found);
        assertEquals(2, cis.getCount());
    }
    
    public void testSkipping() throws IOException {
        String text = "Hello World!";
        byte[] bytes = text.getBytes();
        ByteArrayInputStream bais = new ByteArrayInputStream(bytes);
        CountingInputStream cis = new CountingInputStream(bais);
        
        assertEquals(6,cis.skip(6));
        assertEquals(6,cis.getCount());
        final byte[] result = new byte[6];
        cis.read(result);
        
        assertEquals("World!",new String(result));
        assertEquals(12,cis.getCount());
    }

}