return 0; // Not called.
        }
      }
    }
  }

  /** Returns a new CharBuffer identical to buf, except twice the capacity. */
  private static CharBuffer grow(CharBuffer buf) {
    char[] copy = Arrays.copyOf(buf.array(), buf.capacity() * 2);
    CharBuffer bigger = CharBuffer.wrap(copy);
    Java8Compatibility.position(bigger, buf.position());
    Java8Compatibility.limit(bigger, buf.limit());

      builder.append(buf, 0, read);
    }
    assertThat(builder.toString()).isEqualTo(expected);
    assertFullyRead(reader);

    // read all to one CharBuffer
    reader = new CharSequenceReader(charSequence);
    CharBuffer buf2 = CharBuffer.allocate(expected.length());
    assertEquals(expected.isEmpty() ? -1 : expected.length(), reader.read(buf2));
    Java8Compatibility.flip(buf2);

      builder.append(buf, 0, read);
    }
    assertThat(builder.toString()).isEqualTo(expected);
    assertFullyRead(reader);

    // read all to one CharBuffer
    reader = new CharSequenceReader(charSequence);
    CharBuffer buf2 = CharBuffer.allocate(expected.length());
    assertEquals(expected.isEmpty() ? -1 : expected.length(), reader.read(buf2));
    Java8Compatibility.flip(buf2);

@J2ktIncompatible
@GwtIncompatible
public final class CharStreams {

  // 2K chars (4K bytes)
  private static final int DEFAULT_BUF_SIZE = 0x800;

  /** Creates a new {@code CharBuffer} for buffering reads or writes. */
  static CharBuffer createBuffer() {
    return CharBuffer.allocate(DEFAULT_BUF_SIZE);
  }

  private CharStreams() {}

  /**
   * Copies all characters between the {@link Readable} and {@link Appendable} objects. Does not

import com.google.common.annotations.J2ktIncompatible;
import com.google.errorprone.annotations.CanIgnoreReturnValue;
import java.io.IOException;
import java.io.Reader;
import java.nio.CharBuffer;
import java.util.ArrayDeque;
import java.util.Queue;
import org.jspecify.annotations.Nullable;

/**
 * A class for reading lines of text. Provides the same functionality as {@link

import com.google.caliper.Param;
import com.google.caliper.api.VmOptions;
import java.io.IOException;
import java.io.StringReader;
import java.io.StringWriter;
import java.nio.Buffer;
import java.nio.CharBuffer;
import java.util.Random;
import org.jspecify.annotations.NullUnmarked;

/**
 * Benchmarks for {@link CharStreams#copy}.
 *

  }

  @J2ktIncompatible // J2kt CharBuffer does not implement CharSequence so not recognized as empty
  @GwtIncompatible // CharBuffer not available
  public void testToStringOmitEmptyValues_charBuffer() {
    String toTest =
        MoreObjects.toStringHelper(new TestClass())
            .omitEmptyValues()
            .add("field1", "Hello")
            .add("field2", CharBuffer.allocate(0))
            .toString();

import static java.util.Objects.requireNonNull;

import com.google.common.annotations.GwtIncompatible;
import com.google.common.annotations.J2ktIncompatible;
import java.io.IOException;
import java.io.Reader;
import java.nio.CharBuffer;
import org.jspecify.annotations.Nullable;

/**
 * A {@link Reader} that reads the characters in a {@link CharSequence}. Like {@code StringReader},
 * but works with any {@link CharSequence}.
 *

import com.google.common.collect.Lists;
import java.io.BufferedReader;
import java.io.FilterReader;
import java.io.IOException;
import java.io.Reader;
import java.io.StringReader;
import java.nio.CharBuffer;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import org.jspecify.annotations.NullUnmarked;

/**
 * Unit tests for {@link LineBuffer} and {@link LineReader}.
 *

      File file = getFile();
      Reader reader = new InputStreamReader(new FileInputStream(file), UTF_8);
      StringBuilder builder = new StringBuilder();
      CharBuffer buffer = CharBuffer.allocate(100);
      while (reader.read(buffer) != -1) {
        Java8Compatibility.flip(buffer);
        builder.append(buffer);
        Java8Compatibility.clear(buffer);
      }