examples/csharp/excs_btrec/excs_btrec.cs

   1 /*-
   2  * See the file LICENSE for redistribution information.
   3  *
   4  * Copyright (c) 2009, 2012 Oracle and/or its affiliates.  All rights reserved.
   5  *
   6  */
   7 using System;
   8 using System.IO;
   9 using System.Collections.Generic;
  10 using System.Collections;
  11 using System.Diagnostics;
  12 using System.Text;
  13 using System.Runtime.Serialization.Formatters.Binary;
  14 using BerkeleyDB;
  15
  16 namespace excs_btrec {
  17     class Program {
  18         static void Main(string[] args) {
  19             string dbFileName;
  20             string dbName;
  21             string wordFile;
  22
  23             /*
  24              * excs_btrec is meant to be run from build_windows\AnyCPU, in either
  25              * the Debug or Release directory. The required core libraries,
  26              * however, are in either build_windows\Win32 or build_windows\x64,
  27              * depending upon the platform.  That location needs to be added to
  28              * the PATH environment variable for the P/Invoke calls to work.
  29              */
  30             try {
  31                 String pwd = Environment.CurrentDirectory;
  32                 pwd = Path.Combine(pwd, "..");
  33                 pwd = Path.Combine(pwd, "..");
  34                 if (IntPtr.Size == 4)
  35                     pwd = Path.Combine(pwd, "Win32");
  36                 else
  37                     pwd = Path.Combine(pwd, "x64");
  38 #if DEBUG
  39                 pwd = Path.Combine(pwd, "Debug");
  40 #else
  41                 pwd = Path.Combine(pwd, "Release");
  42 #endif
  43                 pwd += ";" + Environment.GetEnvironmentVariable("PATH");
  44                 Environment.SetEnvironmentVariable("PATH", pwd);
  45             } catch (Exception e) {
  46                 Console.WriteLine(
  47                     "Unable to set the PATH environment variable.");
  48                 Console.WriteLine(e.Message);
  49                 return;
  50             }
  51
  52             try {
  53                 dbFileName = args[0];
  54                 dbName = args[1];
  55                 wordFile = args[2];
  56             } catch {
  57                 usage();
  58                 return;
  59             }
  60
  61             excs_btrec(dbFileName, dbName, wordFile);
  62         }
  63
  64         public static int excs_btrec(string dbFileName,
  65             string dbName, string wordFile) {
  66             BTreeCursor dbc;
  67             BTreeDatabase btreeDB;
  68             BTreeDatabaseConfig btreeDBconfig;
  69             DatabaseEntry key, data;
  70             KeyValuePair<DatabaseEntry, DatabaseEntry> pair;
  71             StreamReader wordList;
  72             string buff;
  73             char[] rbuff;
  74             int i, j;
  75             uint cnt;
  76
  77             string progName = "excs_btrec";
  78
  79             /* Check if word list exists. */
  80             if (!File.Exists(wordFile)) {
  81                 Console.WriteLine("Cannot find {0}/{1}.",
  82                     Environment.CurrentDirectory, wordFile);
  83                 return (1);
  84             }
  85
  86             /* Optionally remove the previous database. */
  87             if (File.Exists(dbFileName)) {
  88                 while (true) {
  89                     Console.Write
  90                         ("Database already exists, delete or not (y/n)?");
  91                     buff = Console.ReadLine();
  92                     if (buff == "y" || buff == "n")
  93                         break;
  94                 }
  95
  96                 if (buff == "y") {
  97                     File.Delete(dbFileName);
  98                     Console.WriteLine("The existing {0} is deleted",
  99                         dbName);
 100                 }
 101             }
 102
 103             /* Create and initialize database object, open the database. */
 104             btreeDBconfig = new BTreeDatabaseConfig();
 105             btreeDBconfig.Creation = CreatePolicy.IF_NEEDED;
 106             btreeDBconfig.ErrorPrefix = progName;
 107             btreeDBconfig.UseRecordNumbers = true;
 108             try {
 109                 btreeDB = BTreeDatabase.Open(dbFileName, dbName,
 110                     btreeDBconfig);
 111             } catch {
 112                 Console.WriteLine("Database can not be opened");
 113                 return (1);
 114             }
 115
 116             /*
 117              * Insert records into the database, where the key is the word
 118              * preceded by its record number, and the data is the same,
 119              * but in reverse order.
 120              */
 121             key = new DatabaseEntry();
 122             data = new DatabaseEntry();
 123             wordList = new StreamReader(wordFile);
 124             for (cnt = 1; cnt <= 1000; cnt++) {
 125                 /* Read one word from word list. */
 126                 try {
 127                     buff = wordList.ReadLine();
 128                 } catch {
 129                     Console.WriteLine("Error when reading word list");
 130                     btreeDB.Close();
 131                     wordList.Close();
 132                     return (1);
 133                 }
 134
 135                 /*
 136                  * Prefix the word with record number and store
 137                  * them in key.
 138                  */
 139                 try {
 140                     buff = cnt.ToString("0000") + buff;
 141                 } catch {
 142                     Console.WriteLine(
 143                         "Wrong format for record number.");
 144                     btreeDB.Close();
 145                     wordList.Close();
 146                     return (1);
 147                 }
 148                 dbtFromString(key, buff);
 149
 150                 /* Reverse buff to rbuff and store them in data. */
 151                 rbuff = new char[buff.Length];
 152                 for (i = 0, j = buff.Length - 1; i < buff.Length; i++, j--)
 153                     rbuff[i] = buff[j];
 154                 dbtFromString(data, new string(rbuff));
 155
 156                 /* Put the key/data pair into database. */
 157                 try {
 158                     btreeDB.PutNoOverwrite(key, data);
 159                 } catch {
 160                     Console.WriteLine("Put error with key::{0} and"
 161                         + "data::{1}", buff, new string(rbuff));
 162                     btreeDB.Close();
 163                     wordList.Close();
 164                     return (1);
 165                 }
 166             }
 167
 168             /* Close the word list. */
 169             wordList.Close();
 170
 171             /* Acquire a cursor for the database. */
 172             dbc = btreeDB.Cursor();
 173
 174             /*
 175              * Input an available record number and get its
 176              * corresponding key/data pair in the database.
 177              */
 178             while (true) {
 179                 Console.WriteLine("Please input record number"
 180                     + ", input 0 to stop");
 181
 182                 while (true) {
 183                     Console.WriteLine("recno #:\t");
 184                     buff = Console.ReadLine();
 185
 186                     try {
 187                         cnt = uint.Parse(buff);
 188                         break;
 189                     } catch {
 190                         Console.WriteLine("Invalid Record Number. "
 191                             + "Try Again.");
 192                     }
 193                 }
 194
 195                 if (cnt == 0)
 196                     break;
 197
 198                 /*
 199                  * Position the cursor at a key/data pair in the database
 200                  * where the record number points to.
 201                  */
 202                 if (!dbc.Move(cnt)) {
 203                     Console.WriteLine("No record is found");
 204                     break;
 205                 }
 206
 207                 /* Get the current key/data pair and display them.*/
 208                 pair = dbc.Current;
 209                 Console.WriteLine("key::{0, 18:G}    data::{1, 18:G}",
 210                     strFromDBT(pair.Key), strFromDBT(pair.Value));
 211
 212                 /* Check if it's the right record number. */
 213                 if (dbc.Recno() != cnt) {
 214                     Console.WriteLine("The current record is not"
 215                         + "the right one of the given record number.");
 216                     btreeDB.Close();
 217                     dbc.Close();
 218                     return (1);
 219                 }
 220
 221                 /* Get the next record. */
 222                 if (!dbc.MoveNext()) {
 223                     Console.WriteLine(
 224                         "Next record is not found");
 225                     break;
 226                 }
 227
 228                 /* Get the current key/data pair and display them.*/
 229                 pair = dbc.Current;
 230                 Console.WriteLine("key::{0, 18:G}    data::{1, 18:G}\n",
 231                     strFromDBT(pair.Key), strFromDBT(pair.Value));
 232
 233             }
 234
 235             /* Close cursor and database. */
 236             dbc.Close();
 237             btreeDB.Close();
 238
 239             return (0);
 240         }
 241
 242         #region Utilities
 243         /* Show the usage. */
 244         public static void usage() {
 245             Console.WriteLine(
 246                 "Usage: [db file name]  [db name] [word list file]");
 247         }
 248
 249         /* Get dbt from string. */
 250         static void dbtFromString(DatabaseEntry dbt, string s) {
 251             dbt.Data = System.Text.Encoding.ASCII.GetBytes(s);
 252         }
 253
 254         /* Get string from dbt. */
 255         public static string strFromDBT(DatabaseEntry dbt) {
 256
 257             System.Text.ASCIIEncoding decode =
 258                 new ASCIIEncoding();
 259             return decode.GetString(dbt.Data);
 260         }
 261         #endregion Utilities
 262     }
 263 }