mcs/class/Npgsql/Npgsql/NpgsqlAsciiRow.cs

   1 // created on 13/6/2002 at 21:06
   2
   3 // Npgsql.NpgsqlAsciiRow.cs
   4 //
   5 // Author:
   6 //      Francisco Jr. (fxjrlists@yahoo.com.br)
   7 //
   8 //      Copyright (C) 2002 The Npgsql Development Team
   9 //      npgsql-general@gborg.postgresql.org
  10 //      http://gborg.postgresql.org/project/npgsql/projdisplay.php
  11 //
  12 // This library is free software; you can redistribute it and/or
  13 // modify it under the terms of the GNU Lesser General Public
  14 // License as published by the Free Software Foundation; either
  15 // version 2.1 of the License, or (at your option) any later version.
  16 //
  17 // This library is distributed in the hope that it will be useful,
  18 // but WITHOUT ANY WARRANTY; without even the implied warranty of
  19 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  20 // Lesser General Public License for more details.
  21 //
  22 // You should have received a copy of the GNU Lesser General Public
  23 // License along with this library; if not, write to the Free Software
  24 // Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  25
  26 using System;
  27 using System.Collections;
  28 using System.IO;
  29 using System.Text;
  30 using System.Net;
  31
  32 using NpgsqlTypes;
  33
  34 namespace Npgsql
  35 {
  36
  37     /// <summary>
  38     /// This class represents the AsciiRow (version 2) and DataRow (version 3+)
  39     /// message sent from the PostgreSQL server.
  40     /// </summary>
  41     internal sealed class NpgsqlAsciiRow : NpgsqlRow
  42     {
  43         // Logging related values
  44         private static readonly String CLASSNAME = "NpgsqlAsciiRow";
  45
  46         private readonly Int16        READ_BUFFER_SIZE = 300; //[FIXME] Is this enough??
  47
  48         public NpgsqlAsciiRow(NpgsqlRowDescription rowDesc, ProtocolVersion protocolVersion)
  49                 : base(rowDesc, protocolVersion)
  50         {
  51             NpgsqlEventLog.LogMethodEnter(LogLevel.Debug, CLASSNAME, CLASSNAME);
  52         }
  53
  54         public override void ReadFromStream(Stream inputStream, Encoding encoding)
  55         {
  56             switch (protocol_version)
  57             {
  58             case ProtocolVersion.Version2 :
  59                 ReadFromStream_Ver_2(inputStream, encoding);
  60                 break;
  61
  62             case ProtocolVersion.Version3 :
  63                 ReadFromStream_Ver_3(inputStream, encoding);
  64                 break;
  65
  66             }
  67         }
  68
  69         private void ReadFromStream_Ver_2(Stream inputStream, Encoding encoding)
  70         {
  71             NpgsqlEventLog.LogMethodEnter(LogLevel.Debug, CLASSNAME, "ReadFromStream_Ver_2");
  72
  73             Byte[]       input_buffer = new Byte[READ_BUFFER_SIZE];
  74             Byte[]       null_map_array = new Byte[(row_desc.NumFields + 7)/8];
  75
  76             Array.Clear(null_map_array, 0, null_map_array.Length);
  77
  78
  79             // Decoders used to get decoded chars when using unicode like encodings which may have chars crossing the byte buffer bounds.
  80
  81             Decoder decoder = encoding.GetDecoder();
  82             Char[] chars = null;
  83             Int32 charCount;
  84
  85
  86             // Read the null fields bitmap.
  87             PGUtil.CheckedStreamRead(inputStream, null_map_array, 0, null_map_array.Length );
  88
  89             // Get the data.
  90             for (Int16 field_count = 0; field_count < row_desc.NumFields; field_count++)
  91             {
  92                 // Check if this field is null
  93                 if (IsBackendNull(null_map_array, field_count))
  94                 {
  95                     data.Add(DBNull.Value);
  96                     continue;
  97                 }
  98
  99                 // Read the first data of the first row.
 100
 101                 PGUtil.CheckedStreamRead(inputStream, input_buffer, 0, 4);
 102
 103                 NpgsqlRowDescriptionFieldData field_descr = row_desc[field_count];
 104                 Int32 field_value_size = IPAddress.NetworkToHostOrder(BitConverter.ToInt32(input_buffer, 0));
 105                 field_value_size -= 4;
 106                 Int32 bytes_left = field_value_size;
 107
 108                 StringBuilder result = new StringBuilder();
 109
 110                 while (bytes_left > READ_BUFFER_SIZE)
 111                 {
 112                     // Now, read just the field value.
 113                     PGUtil.CheckedStreamRead(inputStream, input_buffer, 0, READ_BUFFER_SIZE);
 114
 115                     charCount = decoder.GetCharCount(input_buffer, 0, READ_BUFFER_SIZE);
 116
 117                     chars = new Char[charCount];
 118
 119                     decoder.GetChars(input_buffer, 0, READ_BUFFER_SIZE, chars, 0);
 120
 121                     result.Append(new String(chars));
 122
 123                     bytes_left -= READ_BUFFER_SIZE;
 124                 }
 125
 126                 // Now, read just the field value.
 127                 PGUtil.CheckedStreamRead(inputStream, input_buffer, 0, bytes_left);
 128
 129
 130                 charCount = decoder.GetCharCount(input_buffer, 0, bytes_left);
 131                 chars = new Char[charCount];
 132                 decoder.GetChars(input_buffer, 0, bytes_left, chars, 0);
 133
 134                 result.Append(new String(chars));
 135
 136
 137                 // Add them to the AsciiRow data.
 138                 data.Add(NpgsqlTypesHelper.ConvertBackendStringToSystemType(field_descr.type_info, result.ToString(), field_descr.type_size, field_descr.type_modifier));
 139
 140             }
 141         }
 142
 143         private void ReadFromStream_Ver_3(Stream inputStream, Encoding encoding)
 144         {
 145             NpgsqlEventLog.LogMethodEnter(LogLevel.Debug, CLASSNAME, "ReadFromStream_Ver_3");
 146
 147             Byte[] input_buffer = new Byte[READ_BUFFER_SIZE];
 148
 149             PGUtil.ReadInt32(inputStream, input_buffer);
 150             Int16 numCols = PGUtil.ReadInt16(inputStream, input_buffer);
 151
 152             Decoder decoder = encoding.GetDecoder();
 153             Char[] chars = null;
 154             Int32 charCount;
 155
 156             for (Int16 field_count = 0; field_count < numCols; field_count++)
 157             {
 158                 Int32 field_value_size = PGUtil.ReadInt32(inputStream, input_buffer);
 159
 160                 // Check if this field is null
 161                 if (field_value_size == -1) // Null value
 162                 {
 163                     data.Add(DBNull.Value);
 164                     continue;
 165                 }
 166
 167                 NpgsqlRowDescriptionFieldData field_descr = row_desc[field_count];
 168                 Int32           bytes_left = field_value_size;
 169                 StringBuilder   result = new StringBuilder();
 170
 171                 while (bytes_left > READ_BUFFER_SIZE)
 172                 {
 173
 174                     // Now, read just the field value.
 175                     PGUtil.CheckedStreamRead(inputStream, input_buffer, 0, READ_BUFFER_SIZE);
 176
 177                     // Read the bytes as string.
 178                     //result.Append(new String(encoding.GetChars(input_buffer, 0, READ_BUFFER_SIZE)));
 179                     charCount = decoder.GetCharCount(input_buffer, 0, READ_BUFFER_SIZE);
 180
 181                     chars = new Char[charCount];
 182
 183                     decoder.GetChars(input_buffer, 0, READ_BUFFER_SIZE, chars, 0);
 184
 185                     result.Append(new String(chars));
 186
 187                     bytes_left -= READ_BUFFER_SIZE;
 188
 189                     // Now, read just the field value.
 190                     /*PGUtil.CheckedStreamRead(inputStream, input_buffer, 0, READ_BUFFER_SIZE);
 191
 192                     // Read the bytes as string.
 193                     result.Append(new String(encoding.GetChars(input_buffer, 0, READ_BUFFER_SIZE)));
 194
 195                     bytes_left -= READ_BUFFER_SIZE;*/
 196                 }
 197
 198                 // Now, read just the field value.
 199                 PGUtil.CheckedStreamRead(inputStream, input_buffer, 0, bytes_left);
 200
 201                 if (row_desc[field_count].format_code == FormatCode.Text)
 202                 {
 203                     // Read the bytes as string.
 204                     //result.Append(new String(encoding.GetChars(input_buffer, 0, bytes_left)));
 205
 206
 207                     charCount = decoder.GetCharCount(input_buffer, 0, bytes_left);
 208                     chars = new Char[charCount];
 209                     decoder.GetChars(input_buffer, 0, bytes_left, chars, 0);
 210
 211                     result.Append(new String(chars));
 212
 213                     // Add them to the AsciiRow data.
 214                     data.Add(NpgsqlTypesHelper.ConvertBackendStringToSystemType(field_descr.type_info, result.ToString(), field_descr.type_size, field_descr.type_modifier));
 215
 216                 }
 217                 else
 218                     // FIXME: input_buffer isn't holding all the field value. This code isn't handling binary data correctly.
 219                     data.Add(NpgsqlTypesHelper.ConvertBackendBytesToSystemType(field_descr.type_info, input_buffer, encoding, field_value_size, field_descr.type_modifier));
 220             }
 221         }
 222
 223         // Using the given null field map (provided by the backend),
 224         // determine if the given field index is mapped null by the backend.
 225         // We only need to do this for version 2 protocol.
 226         private static Boolean IsBackendNull(Byte[] null_map_array, Int32 index)
 227         {
 228             // Get the byte that holds the bit index position.
 229             Byte test_byte = null_map_array[index/8];
 230
 231             // Now, check if index bit is set.
 232             // To do this, get its position in the byte, shift to
 233             // MSB and test it with the byte 10000000.
 234             return (((test_byte << (index%8)) & 0x80) == 0);
 235         }
 236     }
 237 }