Drizzled Public API Documentation

random_string.cc
00001 /* - mode: c; c-basic-offset: 2; indent-tabs-mode: nil; -*-
00002  *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
00003  *
00004  *  Copyright (C) 2010 Brian Aker
00005  *
00006  *  This program is free software; you can redistribute it and/or modify
00007  *  it under the terms of the GNU General Public License as published by
00008  *  the Free Software Foundation; either version 2 of the License, or
00009  *  (at your option) any later version.
00010  *
00011  *  This program is distributed in the hope that it will be useful,
00012  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
00013  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00014  *  GNU General Public License for more details.
00015  *
00016  *  You should have received a copy of the GNU General Public License
00017  *  along with this program; if not, write to the Free Software
00018  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
00019  */
00020 
00021 #include <config.h>
00022 
00023 #include <plugin/utility_dictionary/dictionary.h>
00024 
00025 #include <drizzled/atomics.h>
00026 #include <drizzled/session.h>
00027 #include <drizzled/sql_lex.h>
00028 
00029 using namespace drizzled;
00030 using namespace std;
00031 
00032 #define LARGEST_RANDOM_STRING 512
00033 
00034 static const char ALPHANUMERICS[]=
00035   "0123456789ABCDEFGHIJKLMNOPQRSTWXYZabcdefghijklmnopqrstuvwxyz";
00036 
00037 #define ALPHANUMERICS_SIZE (sizeof(ALPHANUMERICS)-1)
00038 
00039 static size_t get_alpha_num(void)
00040 { 
00041     return (size_t)random() % ALPHANUMERICS_SIZE;
00042 }
00043 
00044 utility_dictionary::RandomString::RandomString() :
00045   plugin::TableFunction("DATA_DICTIONARY", "RANDOM_STRING")
00046 {
00047   add_field("VALUE", plugin::TableFunction::STRING, LARGEST_RANDOM_STRING, false);
00048 }
00049 
00050 bool utility_dictionary::RandomString::Generator::populate()
00051 {
00052   if (lex().isSumExprUsed() && count > 0)
00053     return false;
00054 
00055   if (lex().current_select->group_list.elements && count > 0)
00056     return false;
00057 
00058   if (lex().current_select->explicit_limit or count == 0)
00059   {
00060     uint32_t random_char_number= random() % LARGEST_RANDOM_STRING;
00061     char buffer[LARGEST_RANDOM_STRING];
00062 
00063     for (uint32_t x= 0; x < random_char_number; x++)
00064       buffer[x]= ALPHANUMERICS[get_alpha_num()];
00065     buffer[random_char_number]= 0;
00066 
00067     push(buffer, random_char_number);
00068   }
00069   else
00070   {
00071     return false;
00072   }
00073 
00074   count++;
00075 
00076   return true;
00077 }