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package com.thealgorithms.io;
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import org.junit.jupiter.api.Test;
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import static org.junit.jupiter.api.Assertions.*;
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import java.io.ByteArrayInputStream;
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import java.io.ByteArrayOutputStream;
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import java.io.IOException;
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import java.util.*;
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import static org.junit.jupiter.api.Assertions.*;
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import org.junit.jupiter.api.Test;
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class BufferedReaderTest {
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@Test
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public void testPeeks() throws IOException {
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String text = "Hello!\nWorld!";
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int len = text.length();
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byte[] bytes = text.getBytes();
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@Test
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public void testPeeks() throws IOException {
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String text = "Hello!\nWorld!";
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int len = text.length();
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byte[] bytes = text.getBytes();
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ByteArrayInputStream input = new ByteArrayInputStream(bytes);
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BufferedReader reader = new BufferedReader(input);
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ByteArrayInputStream input = new ByteArrayInputStream(bytes);
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BufferedReader reader = new BufferedReader(input);
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// read the first letter
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assertEquals(reader.read(), 'H');
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len--;
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assertEquals(reader.available(), len);
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// read the first letter
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assertEquals(reader.read(), 'H');
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len--;
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assertEquals(reader.available(), len);
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// position: H[e]llo!\nWorld!
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// reader.read() will be == 'e'
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assertEquals(reader.peek(1), 'l');
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assertEquals(reader.peek(2), 'l'); // second l
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assertEquals(reader.peek(3), 'o');
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}
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@Test
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public void testMixes() throws IOException {
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String text = "Hello!\nWorld!";
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int len = text.length();
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byte[] bytes = text.getBytes();
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ByteArrayInputStream input = new ByteArrayInputStream(bytes);
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BufferedReader reader = new BufferedReader(input);
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// read the first letter
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assertEquals(reader.read(), 'H'); // first letter
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len--;
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assertEquals(reader.peek(1), 'l'); // third later (second letter after 'H')
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assertEquals(reader.read(), 'e'); // second letter
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len--;
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assertEquals(reader.available(), len);
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// position: H[e]llo!\nWorld!
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assertEquals(reader.peek(2), 'o'); // second l
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assertEquals(reader.peek(3), '!');
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assertEquals(reader.peek(4), '\n');
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assertEquals(reader.read(), 'l'); // third letter
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assertEquals(reader.peek(1), 'o'); // fourth letter
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for (int i = 0; i < 6; i++)
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reader.read();
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try {
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System.out.println((char) reader.peek(4));
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} catch (Exception ignored) {
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System.out.println("[cached intentional error]");
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// intentional, for testing purpose
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// position: H[e]llo!\nWorld!
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// reader.read() will be == 'e'
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assertEquals(reader.peek(1), 'l');
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assertEquals(reader.peek(2), 'l'); // second l
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assertEquals(reader.peek(3), 'o');
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}
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}
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@Test
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public void testBlockPractical() throws IOException {
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String text = "!Hello\nWorld!";
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byte[] bytes = text.getBytes();
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int len = bytes.length;
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@Test
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public void testMixes() throws IOException {
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String text = "Hello!\nWorld!";
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int len = text.length();
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byte[] bytes = text.getBytes();
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ByteArrayInputStream input = new ByteArrayInputStream(bytes);
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BufferedReader reader = new BufferedReader(input);
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ByteArrayInputStream input = new ByteArrayInputStream(bytes);
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BufferedReader reader = new BufferedReader(input);
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// read the first letter
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assertEquals(reader.read(), 'H'); // first letter
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len--;
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assertEquals(reader.peek(), 'H');
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assertEquals(reader.read(), '!'); // read the first letter
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len--;
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assertEquals(reader.peek(1), 'l'); // third later (second letter after 'H')
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assertEquals(reader.read(), 'e'); // second letter
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len--;
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assertEquals(reader.available(), len);
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// this only reads the next 5 bytes (Hello) because
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// the default buffer size = 5
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assertEquals(new String(reader.readBlock()), "Hello");
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len -= 5;
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assertEquals(reader.available(), len);
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// position: H[e]llo!\nWorld!
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assertEquals(reader.peek(2), 'o'); // second l
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assertEquals(reader.peek(3), '!');
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assertEquals(reader.peek(4), '\n');
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// maybe kind of a practical demonstration / use case
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if (reader.read() == '\n') {
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assertEquals(reader.read(), 'W');
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assertEquals(reader.read(), 'o');
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assertEquals(reader.read(), 'l'); // third letter
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assertEquals(reader.peek(1), 'o'); // fourth letter
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// the rest of the blocks
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assertEquals(new String(reader.readBlock()), "rld!");
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} else {
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// should not reach
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throw new IOException("Something not right");
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for (int i = 0; i < 6; i++) reader.read();
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try {
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System.out.println((char) reader.peek(4));
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} catch (Exception ignored) {
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System.out.println("[cached intentional error]");
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// intentional, for testing purpose
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}
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}
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@Test
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public void testBlockPractical() throws IOException {
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String text = "!Hello\nWorld!";
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byte[] bytes = text.getBytes();
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int len = bytes.length;
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ByteArrayInputStream input = new ByteArrayInputStream(bytes);
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BufferedReader reader = new BufferedReader(input);
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assertEquals(reader.peek(), 'H');
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assertEquals(reader.read(), '!'); // read the first letter
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len--;
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// this only reads the next 5 bytes (Hello) because
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// the default buffer size = 5
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assertEquals(new String(reader.readBlock()), "Hello");
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len -= 5;
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assertEquals(reader.available(), len);
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// maybe kind of a practical demonstration / use case
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if (reader.read() == '\n') {
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assertEquals(reader.read(), 'W');
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assertEquals(reader.read(), 'o');
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// the rest of the blocks
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assertEquals(new String(reader.readBlock()), "rld!");
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} else {
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// should not reach
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throw new IOException("Something not right");
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}
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}
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}
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}
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