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