Drizzled Public API Documentation

left.cc

00001 /* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
00002  *  vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
00003  *
00004  *  Copyright (C) 2008 Sun Microsystems, Inc.
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; version 2 of the License.
00009  *
00010  *  This program is distributed in the hope that it will be useful,
00011  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
00012  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00013  *  GNU General Public License for more details.
00014  *
00015  *  You should have received a copy of the GNU General Public License
00016  *  along with this program; if not, write to the Free Software
00017  *  Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
00018  */
00019 
00020 #include <config.h>
00021 
00022 #include <drizzled/function/str/left.h>
00023 
00024 namespace drizzled
00025 {
00026 
00027 String *Item_func_left::val_str(String *str)
00028 {
00029   assert(fixed == 1);
00030   String *res= args[0]->val_str(str);
00031 
00032   /* must be int64_t to avoid truncation */
00033   int64_t length= args[1]->val_int();
00034   uint32_t char_pos;
00035 
00036   if ((null_value=(args[0]->null_value || args[1]->null_value)))
00037     return 0;
00038 
00039   /* if "unsigned_flag" is set, we have a *huge* positive number. */
00040   if ((length <= 0) && (!args[1]->unsigned_flag))
00041     return &my_empty_string;
00042 
00043   if ((res->length() <= (uint64_t) length) ||
00044       (res->length() <= (char_pos= res->charpos((int) length))))
00045     return res;
00046 
00047   tmp_value.set(*res, 0, char_pos);
00048   return &tmp_value;
00049 }
00050 
00051 void Item_func_left::fix_length_and_dec()
00052 {
00053   collation.set(args[0]->collation);
00054   left_right_max_length();
00055 }
00056 
00057 } /* namespace drizzled */