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 using NpgsqlTypes;
  32
  33
  34 namespace Npgsql
  35 {
  36
  37     /// <summary>
  38     /// This class represents the AsciiRow message sent from PostgreSQL
  39     /// server.
  40     /// </summary>
  41     ///
  42     internal sealed class NpgsqlAsciiRow
  43     {
  44         // Logging related values
  45         private static readonly String CLASSNAME = "NpgsqlAsciiRow";
  46
  47         private ArrayList             data;
  48         private readonly Int16        READ_BUFFER_SIZE = 300; //[FIXME] Is this enough??
  49         private NpgsqlRowDescription  row_desc;
  50         private Hashtable             oid_to_name_mapping;
  51         private ProtocolVersion       protocol_version;
  52
  53
  54
  55         public NpgsqlAsciiRow(NpgsqlRowDescription rowDesc, Hashtable oidToNameMapping, ProtocolVersion protocolVersion)
  56         {
  57             NpgsqlEventLog.LogMethodEnter(LogLevel.Debug, CLASSNAME, CLASSNAME);
  58
  59             data = new ArrayList();
  60             row_desc = rowDesc;
  61             oid_to_name_mapping = oidToNameMapping;
  62             protocol_version = protocolVersion;
  63         }
  64
  65         public void ReadFromStream(Stream inputStream, Encoding encoding)
  66         {
  67             switch (protocol_version) {
  68             case ProtocolVersion.Version2 :
  69                 ReadFromStream_Ver_2(inputStream, encoding);
  70                 break;
  71
  72             case ProtocolVersion.Version3 :
  73                 ReadFromStream_Ver_3(inputStream, encoding);
  74                 break;
  75
  76             }
  77         }
  78
  79         private void ReadFromStream_Ver_2(Stream inputStream, Encoding encoding)
  80         {
  81             NpgsqlEventLog.LogMethodEnter(LogLevel.Debug, CLASSNAME, "ReadFromStream_Ver_2");
  82
  83             Byte[]       input_buffer = new Byte[READ_BUFFER_SIZE];
  84             Byte[]       null_map_array = new Byte[(row_desc.NumFields + 7)/8];
  85
  86             Array.Clear(null_map_array, 0, null_map_array.Length);
  87
  88             // Read the null fields bitmap.
  89             PGUtil.CheckedStreamRead(inputStream, null_map_array, 0, null_map_array.Length );
  90
  91             // Get the data.
  92             for (Int16 field_count = 0; field_count < row_desc.NumFields; field_count++)
  93             {
  94
  95                 // Check if this field isn't null
  96                 if (IsBackendNull(null_map_array, field_count))
  97                 {
  98                     // Field is null just keep next field.
  99
 100                     data.Add(DBNull.Value);
 101                     continue;
 102                 }
 103
 104                 // Read the first data of the first row.
 105
 106                 PGUtil.CheckedStreamRead(inputStream, input_buffer, 0, 4);
 107
 108                 Int32 field_value_size = IPAddress.NetworkToHostOrder(BitConverter.ToInt32(input_buffer, 0));
 109                 field_value_size -= 4;
 110                 Int32 bytes_left = field_value_size;
 111
 112                 StringBuilder result = new StringBuilder();
 113
 114                 while (bytes_left > READ_BUFFER_SIZE)
 115                 {
 116                     // Now, read just the field value.
 117                     PGUtil.CheckedStreamRead(inputStream, input_buffer, 0, READ_BUFFER_SIZE);
 118
 119                     // Read the bytes as string.
 120                     result.Append(new String(encoding.GetChars(input_buffer, 0, READ_BUFFER_SIZE)));
 121
 122                     bytes_left -= READ_BUFFER_SIZE;
 123                 }
 124
 125                 // Now, read just the field value.
 126                 PGUtil.CheckedStreamRead(inputStream, input_buffer, 0, bytes_left);
 127
 128                 // Read the bytes as string.
 129                 result.Append(new String(encoding.GetChars(input_buffer, 0, bytes_left)));
 130
 131
 132                 // Add them to the AsciiRow data.
 133                 data.Add(NpgsqlTypesHelper.ConvertBackendStringToSystemType(oid_to_name_mapping, result.ToString(), row_desc[field_count].type_oid, row_desc[field_count].type_modifier));
 134
 135             }
 136         }
 137
 138         private void ReadFromStream_Ver_3(Stream inputStream, Encoding encoding)
 139         {
 140             NpgsqlEventLog.LogMethodEnter(LogLevel.Debug, CLASSNAME, "ReadFromStream_Ver_3");
 141
 142             Byte[] input_buffer = new Byte[READ_BUFFER_SIZE];
 143
 144             PGUtil.ReadInt32(inputStream, input_buffer);
 145             Int16 numCols = PGUtil.ReadInt16(inputStream, input_buffer);
 146
 147             for (Int16 field_count = 0; field_count < numCols; field_count++)
 148             {
 149                 Int32 field_value_size = PGUtil.ReadInt32(inputStream, input_buffer);
 150
 151                 if (field_value_size == -1) // Null value
 152                 {
 153                     // Field is null just keep next field.
 154
 155                     data.Add(DBNull.Value);
 156                     continue;
 157
 158                 }
 159                 Int32 bytes_left = field_value_size;
 160
 161                 StringBuilder result = new StringBuilder();
 162
 163                 while (bytes_left > READ_BUFFER_SIZE)
 164                 {
 165                     // Now, read just the field value.
 166                     PGUtil.CheckedStreamRead(inputStream, input_buffer, 0, READ_BUFFER_SIZE);
 167
 168                     // Read the bytes as string.
 169                     result.Append(new String(encoding.GetChars(input_buffer, 0, READ_BUFFER_SIZE)));
 170
 171                     bytes_left -= READ_BUFFER_SIZE;
 172                 }
 173
 174                 // Now, read just the field value.
 175                 PGUtil.CheckedStreamRead(inputStream, input_buffer, 0, bytes_left);
 176
 177                 if (row_desc[field_count].format_code == FormatCode.Text)
 178                 {
 179                     // Read the bytes as string.
 180                     result.Append(new String(encoding.GetChars(input_buffer, 0, bytes_left)));
 181                     // Add them to the AsciiRow data.
 182                     data.Add(NpgsqlTypesHelper.ConvertBackendStringToSystemType(oid_to_name_mapping, result.ToString(), row_desc[field_count].type_oid, row_desc[field_count].type_modifier));
 183                 }
 184                 else
 185                     data.Add(NpgsqlTypesHelper.ConvertBackendBytesToStytemType(oid_to_name_mapping, input_buffer, encoding, field_value_size, row_desc[field_count].type_oid, row_desc[field_count].type_modifier));
 186             }
 187         }
 188
 189         // Using the given null field map (provided by the backend),
 190         // determine if the given field index is mapped null by the backend.
 191         // We only need to do this for version 2 protocol.
 192         private static Boolean IsBackendNull(Byte[] null_map_array, Int32 index)
 193         {
 194
 195             // Get the byte that holds the bit index position.
 196             Byte test_byte = null_map_array[index/8];
 197
 198             // Now, check if index bit is set.
 199             // To this, get its position in the byte, shift to
 200             // MSB and test it with the byte 10000000.
 201             return (((test_byte << (index%8)) & 0x80) == 0);
 202         }
 203
 204
 205         public Boolean IsDBNull(Int32 index)
 206         {
 207             NpgsqlEventLog.LogMethodEnter(LogLevel.Debug, CLASSNAME, "IsDBNull", index);
 208
 209             // Check valid index range.
 210             if ((index < 0) || (index >= row_desc.NumFields))
 211                 throw new IndexOutOfRangeException("index");
 212
 213             return (this.data[index] == DBNull.Value);
 214         }
 215
 216         public Object this[Int32 index]
 217         {
 218             get
 219             {
 220
 221                 NpgsqlEventLog.LogIndexerGet(LogLevel.Debug, CLASSNAME, index);
 222
 223                 if ((index < 0) || (index >= row_desc.NumFields))
 224                     throw new IndexOutOfRangeException("this[] index value");
 225
 226                 return data[index];
 227
 228
 229
 230             }
 231         }
 232     }
 233
 234 }