//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 java.util.Map;
//import java.util.Set;
//
//import org.apache.lucene.util.BytesRef;
//import org.apache.lucene.util.UnicodeUtil;
//
///**
// * Abstract base class for performing write operations of Lucene's low-level
// * data types.
//
// * <p>{@code DataOutput} may only be used from one thread, because it is not
// * thread safe (it keeps internal state like file position).
// */
//public abstract class DataOutput {
//
// /** Writes a single byte.
// * <p>
// * The most primitive data type is an eight-bit byte. Files are
// * accessed as sequences of bytes. All other data types are defined
// * as sequences of bytes, so file formats are byte-order independent.
// *
// * @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 DataInput#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 DataInput#readBytes(byte[],int,int)
// */
// public abstract void writeBytes(byte[] b, int offset, int length) throws IOException;
//
// /** Writes an int as four bytes.
// * <p>
// * 32-bit unsigned integer written as four bytes, high-order bytes first.
// *
// * @see DataInput#readInt()
// */
// public void writeInt(int i) throws IOException {
// writeByte((byte)(i >> 24));
// writeByte((byte)(i >> 16));
// writeByte((byte)(i >> 8));
// writeByte((byte) i);
// }
//
// /** Writes a short as two bytes.
// * @see DataInput#readShort()
// */
// public void writeShort(short i) throws IOException {
// 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
// * supported, but should be avoided.
// * <p>VByte is a variable-length format for positive integers is defined where the
// * high-order bit of each byte indicates whether more bytes remain to be read. The
// * low-order seven bits are appended as increasingly more significant bits in the
// * resulting integer value. Thus values from zero to 127 may be stored in a single
// * byte, values from 128 to 16,383 may be stored in two bytes, and so on.</p>
// * <p>VByte Encoding Example</p>
// * <table cellspacing="0" cellpadding="2" border="0">
// * <col width="64*">
// * <col width="64*">
// * <col width="64*">
// * <col width="64*">
// * <tr valign="top">
// * <th align="left" width="25%">Value</th>
// * <th align="left" width="25%">Byte 1</th>
// * <th align="left" width="25%">Byte 2</th>
// * <th align="left" width="25%">Byte 3</th>
// * </tr>
// * <tr valign="bottom">
// * <td width="25%">0</td>
// * <td width="25%"><kbd>00000000</kbd></td>
// * <td width="25%"></td>
// * <td width="25%"></td>
// * </tr>
// * <tr valign="bottom">
// * <td width="25%">1</td>
// * <td width="25%"><kbd>00000001</kbd></td>
// * <td width="25%"></td>
// * <td width="25%"></td>
// * </tr>
// * <tr valign="bottom">
// * <td width="25%">2</td>
// * <td width="25%"><kbd>00000010</kbd></td>
// * <td width="25%"></td>
// * <td width="25%"></td>
// * </tr>
// * <tr>
// * <td valign="top" width="25%">...</td>
// * <td valign="bottom" width="25%"></td>
// * <td valign="bottom" width="25%"></td>
// * <td valign="bottom" width="25%"></td>
// * </tr>
// * <tr valign="bottom">
// * <td width="25%">127</td>
// * <td width="25%"><kbd>01111111</kbd></td>
// * <td width="25%"></td>
// * <td width="25%"></td>
// * </tr>
// * <tr valign="bottom">
// * <td width="25%">128</td>
// * <td width="25%"><kbd>10000000</kbd></td>
// * <td width="25%"><kbd>00000001</kbd></td>
// * <td width="25%"></td>
// * </tr>
// * <tr valign="bottom">
// * <td width="25%">129</td>
// * <td width="25%"><kbd>10000001</kbd></td>
// * <td width="25%"><kbd>00000001</kbd></td>
// * <td width="25%"></td>
// * </tr>
// * <tr valign="bottom">
// * <td width="25%">130</td>
// * <td width="25%"><kbd>10000010</kbd></td>
// * <td width="25%"><kbd>00000001</kbd></td>
// * <td width="25%"></td>
// * </tr>
// * <tr>
// * <td valign="top" width="25%">...</td>
// * <td width="25%"></td>
// * <td width="25%"></td>
// * <td width="25%"></td>
// * </tr>
// * <tr valign="bottom">
// * <td width="25%">16,383</td>
// * <td width="25%"><kbd>11111111</kbd></td>
// * <td width="25%"><kbd>01111111</kbd></td>
// * <td width="25%"></td>
// * </tr>
// * <tr valign="bottom">
// * <td width="25%">16,384</td>
// * <td width="25%"><kbd>10000000</kbd></td>
// * <td width="25%"><kbd>10000000</kbd></td>
// * <td width="25%"><kbd>00000001</kbd></td>
// * </tr>
// * <tr valign="bottom">
// * <td width="25%">16,385</td>
// * <td width="25%"><kbd>10000001</kbd></td>
// * <td width="25%"><kbd>10000000</kbd></td>
// * <td width="25%"><kbd>00000001</kbd></td>
// * </tr>
// * <tr>
// * <td valign="top" width="25%">...</td>
// * <td valign="bottom" width="25%"></td>
// * <td valign="bottom" width="25%"></td>
// * <td valign="bottom" width="25%"></td>
// * </tr>
// * </table>
// * <p>This provides compression while still being efficient to decode.</p>
// *
// * @param i Smaller values take fewer bytes. Negative numbers are
// * supported, but should be avoided.
// * @throws IOException If there is an I/O error writing to the underlying medium.
// * @see DataInput#readVInt()
// */
// public final 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.
// * <p>
// * 64-bit unsigned integer written as eight bytes, high-order bytes first.
// *
// * @see DataInput#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 nine
// * bytes. Smaller values take fewer bytes. Negative numbers are not
// * supported.
// * <p>
// * The format is described further in {@link DataOutput#writeVInt(int)}.
// * @see DataInput#readVLong()
// */
// public final void writeVLong(long i) throws IOException {
// assert i >= 0L;
// while ((i & ~0x7FL) != 0L) {
// writeByte((byte)((i & 0x7FL) | 0x80L));
// i >>>= 7;
// }
// writeByte((byte)i);
// }
//
// /** Writes a string.
// * <p>
// * Writes strings as UTF-8 encoded bytes. First the length, in bytes, is
// * written as a {@link #writeVInt VInt}, followed by the bytes.
// *
// * @see DataInput#readString()
// */
// public void writeString(String s) throws IOException {
// final BytesRef utf8Result = new BytesRef(10);
// UnicodeUtil.UTF16toUTF8(s, 0, s.length(), utf8Result);
// writeVInt(utf8Result.length);
// writeBytes(utf8Result.bytes, 0, utf8Result.length);
// }
//
// private static int COPY_BUFFER_SIZE = 16384;
// private byte[] copyBuffer;
//
// /** Copy numBytes bytes from input to ourself. */
// public void copyBytes(DataInput input, long numBytes) throws IOException {
// assert numBytes >= 0: "numBytes=" + numBytes;
// 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;
// }
// }
//
// /**
// * Writes a String map.
// * <p>
// * First the size is written as an {@link #writeInt(int) Int32},
// * followed by each key-value pair written as two consecutive
// * {@link #writeString(String) String}s.
// *
// * @param map Input map. May be null (equivalent to an empty map)
// */
// public void writeStringStringMap(Map<String,String> map) throws IOException {
// if (map == null) {
// writeInt(0);
// } else {
// writeInt(map.size());
// for(final Map.Entry<String, String> entry: map.entrySet()) {
// writeString(entry.getKey());
// writeString(entry.getValue());
// }
// }
// }
//
// /**
// * Writes a String set.
// * <p>
// * First the size is written as an {@link #writeInt(int) Int32},
// * followed by each value written as a
// * {@link #writeString(String) String}.
// *
// * @param set Input set. May be null (equivalent to an empty set)
// */
// public void writeStringSet(Set<String> set) throws IOException {
// if (set == null) {
// writeInt(0);
// } else {
// writeInt(set.size());
// for(String value : set) {
// writeString(value);
// }
// }
// }
//}