Java Code Examples for java.nio.CharBuffer#slice()

@Test
public void testCopy() {
  CharBuffer sb = CharBuffer.allocate(64);
  sb.position(32);
  CharBuffer slice = sb.slice();
  CharBuffer dest = CharBuffer.allocate(64);
  for(int k = 0; k < 32; ++k)
    slice.put(k, (char) k);
  BufferUtil.arraycopy(slice, 16, dest, 16, 16);
  for(int k = 16; k < 32; ++k)
    assertEquals((char)k,dest.get(k));
  BufferUtil.arraycopy(slice, 0, dest, 16, 16);
  for(int k = 16; k < 32; ++k)
    assertEquals((char)(k-16),dest.get(k));
  BufferUtil.arraycopy(slice, 16, dest, 0, 16);
  for(int k = 0; k < 16; ++k)
    assertEquals((char)(k+16),dest.get(k));

}
 

/**
 * Creates a new big-endian buffer whose content is a subregion of
 * the specified {@code string} encoded in the specified {@code charset}.
 * The new buffer's {@code readerIndex} and {@code writerIndex} are
 * {@code 0} and the length of the encoded string respectively.创建一个新的big-endian缓冲区，其内容是指定字符集中编码的指定字符串的子区域。新缓冲区的readerIndex和writerIndex分别为0和编码字符串的长度。
 */
public static ByteBuf copiedBuffer(
        CharSequence string, int offset, int length, Charset charset) {
    if (string == null) {
        throw new NullPointerException("string");
    }
    if (length == 0) {
        return EMPTY_BUFFER;
    }

    if (string instanceof CharBuffer) {
        CharBuffer buf = (CharBuffer) string;
        if (buf.hasArray()) {
            return copiedBuffer(
                    buf.array(),
                    buf.arrayOffset() + buf.position() + offset,
                    length, charset);
        }

        buf = buf.slice();
        buf.limit(length);
        buf.position(offset);
        return copiedBuffer(buf, charset);
    }

    return copiedBuffer(CharBuffer.wrap(string, offset, offset + length), charset);
}
 

private static void assertRoundTrips(String refStr, int refSubCharLen, int offsetBytes,
    int utf8LengthBytes, byte[] refByteArr, Memory refMem, WritableMemory dstMem)
        throws IOException {
  StringBuilder sb = new StringBuilder();

  int charPos = refMem.getCharsFromUtf8(offsetBytes, utf8LengthBytes, sb);
  checkStrings(sb.toString(), new String(refByteArr, offsetBytes, utf8LengthBytes, UTF_8));
  assertEquals(charPos, refSubCharLen);

  CharBuffer cb = CharBuffer.allocate(refByteArr.length + 1);
  cb.position(1);
  // Make CharBuffer 1-based, to check correct offset handling
  cb = cb.slice();
  refMem.getCharsFromUtf8(offsetBytes, utf8LengthBytes, cb);
  cb.flip();
  checkStrings(cb.toString(), new String(refByteArr, offsetBytes, utf8LengthBytes, UTF_8));

  long encodedUtf8Bytes = dstMem.putCharsToUtf8(0, refStr); //encodes entire refStr
  assertEquals(encodedUtf8Bytes, refByteArr.length); //compares bytes length
  //compare the actual bytes encoded
  assertEquals(0, dstMem.compareTo(0, refByteArr.length, refMem, 0, refByteArr.length));

  // Test write overflow
  WritableMemory writeMem2 = WritableMemory.allocate(refByteArr.length - 1);
  try {
    writeMem2.putCharsToUtf8(0, refStr);
    fail();
  } catch (Utf8CodingException e) {
    // Expected.
  }
}
 

/**
 * Creates a new big-endian buffer whose content is a subregion of
 * the specified {@code string} encoded in the specified {@code charset}.
 * The new buffer's {@code readerIndex} and {@code writerIndex} are
 * {@code 0} and the length of the encoded string respectively.
 */
public static ByteBuf copiedBuffer(
        CharSequence string, int offset, int length, Charset charset) {
    if (string == null) {
        throw new NullPointerException("string");
    }
    if (length == 0) {
        return EMPTY_BUFFER;
    }

    if (string instanceof CharBuffer) {
        CharBuffer buf = (CharBuffer) string;
        if (buf.hasArray()) {
            return copiedBuffer(
                    buf.array(),
                    buf.arrayOffset() + buf.position() + offset,
                    length, charset);
        }

        buf = buf.slice();
        buf.limit(length);
        buf.position(offset);
        return copiedBuffer(buf, charset);
    }

    return copiedBuffer(CharBuffer.wrap(string, offset, offset + length), charset);
}
 

public void testBufferWithNonZeroOffset() {
    CharsetDecoder decoder = Charset.forName("UTF-8").newDecoder();
    CharBuffer cb = CharBuffer.allocate(128);
    cb.position(42);
    CharBuffer out = cb.slice();
    CoderResult cr = decoder.decode(
            ByteBuffer.wrap(new byte[] { 'h', 'e', 'l', 'l', 'o'}), out, false);
    assertTrue(cr.isUnderflow());
    assertEquals(5, out.position());
}
 

/**
 * Creates a new buffer with the specified {@code endianness} whose
 * content is a subregion of the specified {@code string} encoded in the
 * specified {@code charset}.  The new buffer's {@code readerIndex} and
 * {@code writerIndex} are {@code 0} and the length of the encoded string
 * respectively.
 */
public static ChannelBuffer copiedBuffer(
        ByteOrder endianness, CharSequence string, int offset, int length, Charset charset) {
    if (string == null) {
        throw new NullPointerException("string");
    }
    if (length == 0) {
        return EMPTY_BUFFER;
    }

    if (string instanceof CharBuffer) {
        CharBuffer buf = (CharBuffer) string;
        if (buf.hasArray()) {
            return copiedBuffer(
                    endianness,
                    buf.array(),
                    buf.arrayOffset() + buf.position() + offset,
                    length, charset);
        }

        buf = buf.slice();
        buf.limit(length);
        buf.position(offset);
        return copiedBuffer(endianness, buf, charset);
    }

    return copiedBuffer(
            endianness, CharBuffer.wrap(string, offset, offset + length),
            charset);
}
 

/**
 * Creates a new buffer with the specified {@code endianness} whose
 * content is a subregion of the specified {@code string} encoded in the
 * specified {@code charset}.  The new buffer's {@code readerIndex} and
 * {@code writerIndex} are {@code 0} and the length of the encoded string
 * respectively.
 */
public static ChannelBuffer copiedBuffer(
        ByteOrder endianness, CharSequence string, int offset, int length, Charset charset) {
    if (string == null) {
        throw new NullPointerException("string");
    }
    if (length == 0) {
        return EMPTY_BUFFER;
    }

    if (string instanceof CharBuffer) {
        CharBuffer buf = (CharBuffer) string;
        if (buf.hasArray()) {
            return copiedBuffer(
                    endianness,
                    buf.array(),
                    buf.arrayOffset() + buf.position() + offset,
                    length, charset);
        }

        buf = buf.slice();
        buf.limit(length);
        buf.position(offset);
        return copiedBuffer(endianness, buf, charset);
    }

    return copiedBuffer(
            endianness, CharBuffer.wrap(string, offset, offset + length),
            charset);
}
 

/**
 *
 * @param args
 */
public static void main(String args[]) {
    CharBuffer charBuffer = CharBuffer.allocate(BUF_SIZE);
    File file = new File("temp.txt");
    file.deleteOnExit();

    charBuffer.put(str);
    charBuffer.flip();
    checkFileContent(charBuffer, file, str);
    charBuffer.position(10);
    checkFileContent(charBuffer, file, str.substring(10));
    charBuffer.position(charBuffer.limit());
    checkFileContent(charBuffer, file, str.substring(charBuffer.limit()));

    char arr[] = new char[BUF_SIZE];
    charBuffer = CharBuffer.wrap(arr);
    charBuffer.put(str);
    charBuffer.flip();
    checkFileContent(charBuffer, file, str);
    charBuffer.position(10);
    checkFileContent(charBuffer, file, str.substring(10));
    charBuffer.position(charBuffer.limit());
    checkFileContent(charBuffer, file, str.substring(charBuffer.limit()));

    char secArr[] = new char[BUF_SIZE];
    charBuffer = CharBuffer.wrap(secArr);
    charBuffer.put(str);
    charBuffer.position(5);
    charBuffer.limit(str.length() - 7);
    charBuffer = charBuffer.slice();
    checkFileContent(charBuffer, file, str.substring(5, (str.length() - 7)));
    charBuffer.position(10);
    checkFileContent(charBuffer, file, str.substring(15, (str.length() - 7)));
    charBuffer.position(charBuffer.limit());
    checkFileContent(charBuffer, file, str.substring(charBuffer.limit()));

    charBuffer = ByteBuffer.allocate(BUF_SIZE).asCharBuffer();
    charBuffer.put(str);
    charBuffer.flip();
    checkFileContent(charBuffer, file, str);
    charBuffer.position(10);
    checkFileContent(charBuffer, file, str.substring(10));
    charBuffer.position(charBuffer.limit());
    checkFileContent(charBuffer, file, str.substring(charBuffer.limit()));

    charBuffer = ByteBuffer.allocateDirect(1024).asCharBuffer();
    charBuffer.put(str);
    charBuffer.flip();
    checkFileContent(charBuffer, file, str);
    charBuffer.position(10);
    checkFileContent(charBuffer, file, str.substring(10));
    charBuffer.position(charBuffer.limit());
    checkFileContent(charBuffer, file, str.substring(charBuffer.limit()));
}
 

public CharBufferStream(CharBuffer buf) {
    this.buf = buf.slice();
    this.n = this.buf.limit();
}
 

public static String toString(CharBuffer buffer) {
  buffer = buffer.slice();
  char [] buf = new char [buffer.remaining()];
  buffer.get(buf);
  return new String(buf);
}