package org.apache.lucene.store;/** * 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. */import java.io.IOException;import org.apache.lucene.util.UnicodeUtil;/** Abstract base class for output to a file in a Directory.  A random-access * output stream.  Used for all Lucene index output operations. * @see Directory * @see IndexInput */public abstract class IndexOutput {  private UnicodeUtil.UTF8Result utf8Result = new UnicodeUtil.UTF8Result();  /** Writes a single byte.   * @see IndexInput#readByte()   */  public abstract void writeByte(byte b) throws IOException;  /** Writes an array of bytes.   * @param b the bytes to write   * @param length the number of bytes to write   * @see IndexInput#readBytes(byte[],int,int)   */  public void writeBytes(byte[] b, int length) throws IOException {    writeBytes(b, 0, length);  }  /** Writes an array of bytes.   * @param b the bytes to write   * @param offset the offset in the byte array   * @param length the number of bytes to write   * @see IndexInput#readBytes(byte[],int,int)   */  public abstract void writeBytes(byte[] b, int offset, int length) throws IOException;  /** Writes an int as four bytes.   * @see IndexInput#readInt()   */  public void writeInt(int i) throws IOException {    writeByte((byte)(i >> 24));    writeByte((byte)(i >> 16));    writeByte((byte)(i >>  8));    writeByte((byte) i);  }  /** Writes an int in a variable-length format.  Writes between one and   * five bytes.  Smaller values take fewer bytes.  Negative numbers are not   * supported.   * @see IndexInput#readVInt()   */  public void writeVInt(int i) throws IOException {    while ((i & ~0x7F) != 0) {      writeByte((byte)((i & 0x7f) | 0x80));      i >>>= 7;    }    writeByte((byte)i);  }  /** Writes a long as eight bytes.   * @see IndexInput#readLong()   */  public void writeLong(long i) throws IOException {    writeInt((int) (i >> 32));    writeInt((int) i);  }  /** Writes an long in a variable-length format.  Writes between one and five   * bytes.  Smaller values take fewer bytes.  Negative numbers are not   * supported.   * @see IndexInput#readVLong()   */  public void writeVLong(long i) throws IOException {    while ((i & ~0x7F) != 0) {      writeByte((byte)((i & 0x7f) | 0x80));      i >>>= 7;    }    writeByte((byte)i);  }  /** Writes a string.   * @see IndexInput#readString()   */  public void writeString(String s) throws IOException {    UnicodeUtil.UTF16toUTF8(s, 0, s.length(), utf8Result);    writeVInt(utf8Result.length);    writeBytes(utf8Result.result, 0, utf8Result.length);  }  /** Writes a sub sequence of characters from s as the old   *  format (modified UTF-8 encoded bytes).   * @param s the source of the characters   * @param start the first character in the sequence   * @param length the number of characters in the sequence   * @deprecated -- please pre-convert to utf8 bytes   * instead or use {@link #writeString}   */  public void writeChars(String s, int start, int length)       throws IOException {    final int end = start + length;    for (int i = start; i < end; i++) {      final int code = (int)s.charAt(i);      if (code >= 0x01 && code <= 0x7F)	writeByte((byte)code);      else if (((code >= 0x80) && (code <= 0x7FF)) || code == 0) {	writeByte((byte)(0xC0 | (code >> 6)));	writeByte((byte)(0x80 | (code & 0x3F)));      } else {	writeByte((byte)(0xE0 | (code >>> 12)));	writeByte((byte)(0x80 | ((code >> 6) & 0x3F)));	writeByte((byte)(0x80 | (code & 0x3F)));      }    }  }  /** Writes a sub sequence of characters from char[] as   *  the old format (modified UTF-8 encoded bytes).   * @param s the source of the characters   * @param start the first character in the sequence   * @param length the number of characters in the sequence   * @deprecated -- please pre-convert to utf8 bytes instead or use {@link #writeString}   */  public void writeChars(char[] s, int start, int length)    throws IOException {    final int end = start + length;    for (int i = start; i < end; i++) {      final int code = (int)s[i];      if (code >= 0x01 && code <= 0x7F)	writeByte((byte)code);      else if (((code >= 0x80) && (code <= 0x7FF)) || code == 0) {	writeByte((byte)(0xC0 | (code >> 6)));	writeByte((byte)(0x80 | (code & 0x3F)));      } else {	writeByte((byte)(0xE0 | (code >>> 12)));	writeByte((byte)(0x80 | ((code >> 6) & 0x3F)));	writeByte((byte)(0x80 | (code & 0x3F)));      }    }  }  private static int COPY_BUFFER_SIZE = 16384;  private byte[] copyBuffer;  /** Copy numBytes bytes from input to ourself. */  public void copyBytes(IndexInput input, long numBytes) throws IOException {    long left = numBytes;    if (copyBuffer == null)      copyBuffer = new byte[COPY_BUFFER_SIZE];    while(left > 0) {      final int toCopy;      if (left > COPY_BUFFER_SIZE)        toCopy = COPY_BUFFER_SIZE;      else        toCopy = (int) left;      input.readBytes(copyBuffer, 0, toCopy);      writeBytes(copyBuffer, 0, toCopy);      left -= toCopy;    }  }  /** Forces any buffered output to be written. */  public abstract void flush() throws IOException;  /** Closes this stream to further operations. */  public abstract void close() throws IOException;  /** Returns the current position in this file, where the next write will   * occur.   * @see #seek(long)   */  public abstract long getFilePointer();  /** Sets current position in this file, where the next write will occur.   * @see #getFilePointer()   */  public abstract void seek(long pos) throws IOException;  /** The number of bytes in the file. */  public abstract long length() throws IOException;  /** Set the file length. By default, this method does   * nothing (it's optional for a Directory to implement   * it).  But, certain Directory implementations (for   * example @see FSDirectory) can use this to inform the   * underlying IO system to pre-allocate the file to the   * specified size.  If the length is longer than the   * current file length, the bytes added to the file are   * undefined.  Otherwise the file is truncated.   * @param length file length   */  public void setLength(long length) throws IOException {};}