beagled/Lucene.Net/Store/IndexOutput.cs

   1 /*
   2  * Copyright 2005 The Apache Software Foundation
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  * http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16 using System;
  17 namespace Lucene.Net.Store
  18 {
  19
  20     /// <summary>Abstract base class for output to a file in a Directory.  A random-access
  21     /// output stream.  Used for all Lucene index output operations.
  22     /// </summary>
  23     /// <seealso cref="Directory">
  24     /// </seealso>
  25     /// <seealso cref="IndexInput">
  26     /// </seealso>
  27     public abstract class IndexOutput
  28     {
  29
  30         /// <summary>Writes a single byte.</summary>
  31         /// <seealso cref="IndexInput#ReadByte()">
  32         /// </seealso>
  33         public abstract void  WriteByte(byte b);
  34
  35         /// <summary>Writes an array of bytes.</summary>
  36         /// <param name="b">the bytes to write
  37         /// </param>
  38         /// <param name="length">the number of bytes to write
  39         /// </param>
  40         /// <seealso cref="IndexInput#ReadBytes(byte[],int,int)">
  41         /// </seealso>
  42         public abstract void  WriteBytes(byte[] b, int length);
  43
  44         /// <summary>Writes an int as four bytes.</summary>
  45         /// <seealso cref="IndexInput#ReadInt()">
  46         /// </seealso>
  47         public virtual void  WriteInt(int i)
  48         {
  49             WriteByte((byte) (i >> 24));
  50             WriteByte((byte) (i >> 16));
  51             WriteByte((byte) (i >> 8));
  52             WriteByte((byte) i);
  53         }
  54
  55         /// <summary>Writes an int in a variable-length format.  Writes between one and
  56         /// five bytes.  Smaller values take fewer bytes.  Negative numbers are not
  57         /// supported.
  58         /// </summary>
  59         /// <seealso cref="IndexInput#ReadVInt()">
  60         /// </seealso>
  61         public virtual void  WriteVInt(int i)
  62         {
  63             while ((i & ~ 0x7F) != 0)
  64             {
  65                 WriteByte((byte) ((i & 0x7f) | 0x80));
  66                 i = (int) (((uint) i) >> 7);
  67             }
  68             WriteByte((byte) i);
  69         }
  70
  71         /// <summary>Writes a long as eight bytes.</summary>
  72         /// <seealso cref="IndexInput#ReadLong()">
  73         /// </seealso>
  74         public virtual void  WriteLong(long i)
  75         {
  76             WriteInt((int) (i >> 32));
  77             WriteInt((int) i);
  78         }
  79
  80         /// <summary>Writes an long in a variable-length format.  Writes between one and five
  81         /// bytes.  Smaller values take fewer bytes.  Negative numbers are not
  82         /// supported.
  83         /// </summary>
  84         /// <seealso cref="IndexInput#ReadVLong()">
  85         /// </seealso>
  86         public virtual void  WriteVLong(long i)
  87         {
  88             while ((i & ~ 0x7F) != 0)
  89             {
  90                 WriteByte((byte) ((i & 0x7f) | 0x80));
  91                 i = (int) (((uint) i) >> 7);
  92             }
  93             WriteByte((byte) i);
  94         }
  95
  96         /// <summary>Writes a string.</summary>
  97         /// <seealso cref="IndexInput#ReadString()">
  98         /// </seealso>
  99         public virtual void  WriteString(System.String s)
 100         {
 101             int length = s.Length;
 102             WriteVInt(length);
 103             WriteChars(s, 0, length);
 104         }
 105
 106         /// <summary>Writes a sequence of UTF-8 encoded characters from a string.</summary>
 107         /// <param name="s">the source of the characters
 108         /// </param>
 109         /// <param name="start">the first character in the sequence
 110         /// </param>
 111         /// <param name="length">the number of characters in the sequence
 112         /// </param>
 113         /// <seealso cref="IndexInput#ReadChars(char[],int,int)">
 114         /// </seealso>
 115         public virtual void  WriteChars(System.String s, int start, int length)
 116         {
 117             int end = start + length;
 118             for (int i = start; i < end; i++)
 119             {
 120                 int code = (int) s[i];
 121                 if (code >= 0x01 && code <= 0x7F)
 122                     WriteByte((byte) code);
 123                 else if (((code >= 0x80) && (code <= 0x7FF)) || code == 0)
 124                 {
 125                     WriteByte((byte) (0xC0 | (code >> 6)));
 126                     WriteByte((byte) (0x80 | (code & 0x3F)));
 127                 }
 128                 else
 129                 {
 130                     WriteByte((byte) (0xE0 | ((int) (((uint) code) >> 12))));
 131                     WriteByte((byte) (0x80 | ((code >> 6) & 0x3F)));
 132                     WriteByte((byte) (0x80 | (code & 0x3F)));
 133                 }
 134             }
 135         }
 136
 137         /// <summary>Forces any buffered output to be written. </summary>
 138         public abstract void  Flush();
 139
 140         /// <summary>Closes this stream to further operations. </summary>
 141         public abstract void  Close();
 142
 143         /// <summary>Returns the current position in this file, where the next write will
 144         /// occur.
 145         /// </summary>
 146         /// <seealso cref="#Seek(long)">
 147         /// </seealso>
 148         public abstract long GetFilePointer();
 149
 150         /// <summary>Sets current position in this file, where the next write will occur.</summary>
 151         /// <seealso cref="#GetFilePointer()">
 152         /// </seealso>
 153         public abstract void  Seek(long pos);
 154
 155         /// <summary>The number of bytes in the file. </summary>
 156         public abstract long Length();
 157     }
 158 }