class/FirebirdSql.Data.Firebird/FirebirdSql.Data.Common/BlobBase.cs

   1 /*
   2  *  Firebird ADO.NET Data provider for .NET and Mono
   3  *
   4  *     The contents of this file are subject to the Initial
   5  *     Developer's Public License Version 1.0 (the "License");
   6  *     you may not use this file except in compliance with the
   7  *     License. You may obtain a copy of the License at
   8  *     http://www.firebirdsql.org/index.php?op=doc&id=idpl
   9  *
  10  *     Software distributed under the License is distributed on
  11  *     an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either
  12  *     express or implied.  See the License for the specific
  13  *     language governing rights and limitations under the License.
  14  *
  15  *  Copyright (c) 2002, 2005 Carlos Guzman Alvarez
  16  *  All Rights Reserved.
  17  */
  18
  19 using System;
  20 using System.Data;
  21 using System.Text;
  22 using System.IO;
  23 using System.Collections;
  24
  25 namespace FirebirdSql.Data.Common
  26 {
  27         internal abstract class BlobBase
  28         {
  29                 #region Fields
  30
  31                 private int             rblFlags;
  32                 private Charset charset;
  33                 private int             segmentSize;
  34
  35                 #endregion
  36
  37                 #region Protected Fields
  38
  39                 protected long  blobId;
  40                 protected int   blobHandle;
  41                 protected int   position;
  42                 protected ITransaction transaction;
  43
  44                 #endregion
  45
  46                 #region Properties
  47
  48                 public int Handle
  49                 {
  50                         get { return this.blobHandle; }
  51                 }
  52
  53                 public long Id
  54                 {
  55                         get { return this.blobId; }
  56                 }
  57
  58                 public bool EOF
  59                 {
  60                         get { return (this.rblFlags & IscCodes.RBL_eof_pending) != 0; }
  61                 }
  62
  63                 #endregion
  64
  65                 #region Protected Properties
  66
  67                 protected int SegmentSize
  68                 {
  69                         get { return this.segmentSize; }
  70                 }
  71
  72                 #endregion
  73
  74                 #region Abstract Properties
  75
  76                 public abstract IDatabase DB
  77                 {
  78                         get;
  79                 }
  80
  81                 #endregion
  82
  83                 #region Constructors
  84
  85                 protected BlobBase(IDatabase db)
  86                 {
  87                         this.segmentSize = db.PacketSize;
  88                         this.charset = db.Charset;
  89                 }
  90
  91                 #endregion
  92
  93                 #region Protected Abstract Methods
  94
  95                 protected abstract void Create();
  96                 protected abstract void Open();
  97                 protected abstract byte[] GetSegment();
  98                 protected abstract void PutSegment(byte[] buffer);
  99                 protected abstract void Seek(int position);
 100                 protected abstract void GetBlobInfo();
 101                 protected abstract void Close();
 102                 protected abstract void Cancel();
 103
 104                 #endregion
 105
 106                 #region Methods
 107
 108                 public string ReadString()
 109                 {
 110                         byte[] buffer = this.Read();
 111                         return this.charset.GetString(buffer, 0, buffer.Length);
 112                 }
 113
 114                 public byte[] Read()
 115                 {
 116                         MemoryStream ms = new MemoryStream();
 117
 118                         try
 119                         {
 120                                 this.Open();
 121
 122                                 while (!EOF)
 123                                 {
 124                                         byte[] segment = this.GetSegment();
 125                                         ms.Write(segment, 0, segment.Length);
 126                                 }
 127
 128                                 this.Close();
 129                         }
 130                         catch (Exception)
 131                         {
 132                                 // Cancel the blob and rethrow the exception
 133                                 this.Cancel();
 134
 135                                 throw;
 136                         }
 137
 138                         return ms.ToArray();
 139                 }
 140
 141                 public void Write(string data)
 142                 {
 143                         this.Write(this.charset.GetBytes(data));
 144                 }
 145
 146                 public void Write(byte[] buffer)
 147                 {
 148                         this.Write(buffer, 0, buffer.Length);
 149                 }
 150
 151                 public void Write(byte[] buffer, int index, int count)
 152                 {
 153                         try
 154                         {
 155                                 this.Create();
 156
 157                                 byte[] tmpBuffer = null;
 158
 159                                 int length      = count;
 160                                 int offset      = index;
 161                                 int chunk       = length >= this.segmentSize ? this.segmentSize : length;
 162
 163                                 tmpBuffer = new byte[chunk];
 164
 165                                 while (length > 0)
 166                                 {
 167                                         if (chunk > length)
 168                                         {
 169                                                 chunk = (int)length;
 170                                                 tmpBuffer = new byte[chunk];
 171                                         }
 172
 173                                         Array.Copy(buffer, offset, tmpBuffer, 0, chunk);
 174                                         this.PutSegment(tmpBuffer);
 175
 176                                         offset += chunk;
 177                                         length -= chunk;
 178                                 }
 179
 180                                 this.Close();
 181                         }
 182                         catch (Exception)
 183                         {
 184                                 // Cancel the blob and rethrow the exception
 185                                 this.Cancel();
 186
 187                                 throw;
 188                         }
 189                 }
 190
 191                 #endregion
 192
 193                 #region Protected Methods
 194
 195                 protected void RblAddValue(int rblValue)
 196                 {
 197                         this.rblFlags |= rblValue;
 198                 }
 199
 200                 protected void RblRemoveValue(int rblValue)
 201                 {
 202                         this.rblFlags &= ~rblValue;
 203                 }
 204
 205                 #endregion
 206         }
 207 }