test/jdk/java/io/InputStreamReader/ReadCharBuffer.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * This code is free software; you can redistribute it and/or modify it
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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/*
 * @test
 * @bug 4926314 8287003
 * @summary Test for InputStreamReader#read(CharBuffer).
 * @run testng ReadCharBuffer
 */

import org.testng.annotations.DataProvider;
import org.testng.annotations.Test;


import java.io.ByteArrayInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.Reader;
import java.nio.ByteBuffer;
import java.nio.CharBuffer;
import java.nio.charset.CodingErrorAction;
import java.util.Arrays;

import static java.nio.charset.StandardCharsets.US_ASCII;
import static java.nio.charset.StandardCharsets.UTF_8;
import static org.testng.Assert.assertEquals;

public class ReadCharBuffer {

    private static final int BUFFER_SIZE = 24;

    @DataProvider(name = "buffers")
    public Object[][] createBuffers() {
        // test both on-heap and off-heap buffers as they make use different code paths
        return new Object[][]{
                new Object[]{CharBuffer.allocate(BUFFER_SIZE)},
                new Object[]{ByteBuffer.allocateDirect(BUFFER_SIZE * 2).asCharBuffer()}
        };
    }

    private void fillBuffer(CharBuffer buffer) {
        char[] filler = new char[BUFFER_SIZE];
        Arrays.fill(filler, 'x');
        buffer.put(filler);
        buffer.clear();
    }

    @Test(dataProvider = "buffers")
    public void read(CharBuffer buffer) throws IOException {
        fillBuffer(buffer);

        try (Reader reader = new InputStreamReader(new ByteArrayInputStream("ABCDEFGHIJKLMNOPQRTUVWXYZ".getBytes(US_ASCII)), US_ASCII)) {
            buffer.limit(7);
            buffer.position(1);
            assertEquals(reader.read(buffer), 6);
            assertEquals(buffer.position(), 7);
            assertEquals(buffer.limit(), 7);

            buffer.limit(16);
            buffer.position(8);
            assertEquals(reader.read(buffer), 8);
            assertEquals(buffer.position(), 16);
            assertEquals(buffer.limit(), 16);
        }

        buffer.clear();
        assertEquals(buffer.toString(), "xABCDEFxGHIJKLMNxxxxxxxx");
    }

    @Test
    public void readLeftover() throws IOException {
        byte[] b = new byte[] {'a', 'b', (byte) 0xC2};
        ByteArrayInputStream bais = new ByteArrayInputStream(b);
        InputStreamReader r = new InputStreamReader(bais,
            UTF_8.newDecoder().onMalformedInput(CodingErrorAction.IGNORE));
        int n = r.read();
        assertEquals((char)n, 'a');
        char[] c = new char[3];
        n = r.read(c, 0, 3);
        assertEquals(n, 1);
        assertEquals((char)c[0], 'b');
        n = r.read();
        assertEquals(n, -1);
    }
}