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- Committer: Stewart Smith
- Date: 2010-02-15 03:55:09 UTC
- mto: (1273.13.96 build)
- mto: This revision was merged to the branch mainline in revision 1308.
- Revision ID: stewart@flamingspork.com-20100215035509-y6sry4q4yymph2by
move SUBSTR, SUBSTRING and SUBSTR_INDEX to plugins. add parser hooks for substr being a plugin now.
- files added:
- plugin/substr_functions
- files removed:
- drizzled/function/str/substr.cc
- files modified:
- drizzled/include.am
added
removed
drizzled/function/str/substr.cc
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/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
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* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
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*
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* Copyright (C) 2008 Sun Microsystems
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; version 2 of the License.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#include "config.h"
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#include <drizzled/function/str/substr.h>
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#include <algorithm>
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using namespace std;
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namespace drizzled
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{
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String *Item_func_substr::val_str(String *str)
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{
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assert(fixed == 1);
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String *res = args[0]->val_str(str);
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/* must be int64_t to avoid truncation */
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int64_t start= args[1]->val_int();
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/* Assumes that the maximum length of a String is < INT32_MAX. */
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/* Limit so that code sees out-of-bound value properly. */
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int64_t length= arg_count == 3 ? args[2]->val_int() : INT32_MAX;
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int64_t tmp_length;
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if ((null_value=(args[0]->null_value || args[1]->null_value ||
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(arg_count == 3 && args[2]->null_value))))
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return 0;
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/* Negative or zero length, will return empty string. */
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if ((arg_count == 3) && (length <= 0) &&
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(length == 0 || !args[2]->unsigned_flag))
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return &my_empty_string;
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/* Assumes that the maximum length of a String is < INT32_MAX. */
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/* Set here so that rest of code sees out-of-bound value as such. */
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if ((length <= 0) || (length > INT32_MAX))
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length= INT32_MAX;
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/* if "unsigned_flag" is set, we have a *huge* positive number. */
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/* Assumes that the maximum length of a String is < INT32_MAX. */
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if ((!args[1]->unsigned_flag && (start < INT32_MIN || start > INT32_MAX)) ||
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(args[1]->unsigned_flag && ((uint64_t) start > INT32_MAX)))
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return &my_empty_string;
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start= ((start < 0) ? res->numchars() + start : start - 1);
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start= res->charpos((int) start);
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if ((start < 0) || ((uint) start + 1 > res->length()))
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return &my_empty_string;
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length= res->charpos((int) length, (uint32_t) start);
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tmp_length= res->length() - start;
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length= min(length, tmp_length);
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if (!start && (int64_t) res->length() == length)
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return res;
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tmp_value.set(*res, (uint32_t) start, (uint32_t) length);
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return &tmp_value;
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}
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void Item_func_substr::fix_length_and_dec()
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{
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max_length=args[0]->max_length;
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collation.set(args[0]->collation);
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if (args[1]->const_item())
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{
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int32_t start= (int32_t) args[1]->val_int();
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if (start < 0)
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max_length= ((uint)(-start) > max_length) ? 0 : (uint)(-start);
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else
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max_length-= min((uint)(start - 1), max_length);
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}
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if (arg_count == 3 && args[2]->const_item())
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{
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int32_t length= (int32_t) args[2]->val_int();
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if (length <= 0)
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max_length=0;
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else
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set_if_smaller(max_length,(uint) length);
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}
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max_length*= collation.collation->mbmaxlen;
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}
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void Item_func_substr_index::fix_length_and_dec()
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{
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max_length= args[0]->max_length;
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if (agg_arg_charsets(collation, args, 2, MY_COLL_CMP_CONV, 1))
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return;
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}
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String *Item_func_substr_index::val_str(String *str)
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{
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assert(fixed == 1);
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String *res= args[0]->val_str(str);
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String *delimiter= args[1]->val_str(&tmp_value);
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int32_t count= (int32_t) args[2]->val_int();
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uint32_t offset;
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if (args[0]->null_value || args[1]->null_value || args[2]->null_value)
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{ // string and/or delim are null
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null_value=1;
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return 0;
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}
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null_value=0;
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uint32_t delimiter_length= delimiter->length();
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if (!res->length() || !delimiter_length || !count)
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return &my_empty_string; // Wrong parameters
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res->set_charset(collation.collation);
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if (use_mb(res->charset()))
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{
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const char *ptr= res->ptr();
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const char *strend= ptr+res->length();
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const char *end= strend-delimiter_length+1;
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const char *search= delimiter->ptr();
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const char *search_end= search+delimiter_length;
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int32_t n=0,c=count,pass;
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register uint32_t l;
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for (pass=(count>0);pass<2;++pass)
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{
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while (ptr < end)
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{
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if (*ptr == *search)
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{
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register char *i,*j;
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i=(char*) ptr+1; j=(char*) search+1;
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while (j != search_end)
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if (*i++ != *j++) goto skip;
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if (pass==0) ++n;
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else if (!--c) break;
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ptr+= delimiter_length;
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continue;
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}
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skip:
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if ((l=my_ismbchar(res->charset(), ptr,strend))) ptr+=l;
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else ++ptr;
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} /* either not found or got total number when count<0 */
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if (pass == 0) /* count<0 */
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{
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c+=n+1;
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if (c<=0) return res; /* not found, return original string */
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ptr=res->ptr();
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}
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else
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{
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if (c) return res; /* Not found, return original string */
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if (count>0) /* return left part */
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{
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tmp_value.set(*res,0,(ulong) (ptr-res->ptr()));
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}
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else /* return right part */
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{
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ptr+= delimiter_length;
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tmp_value.set(*res,(ulong) (ptr-res->ptr()), (ulong) (strend-ptr));
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}
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}
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}
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}
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else
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{
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if (count > 0)
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{ // start counting from the beginning
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for (offset=0; ; offset+= delimiter_length)
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{
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if ((int) (offset= res->strstr(*delimiter, offset)) < 0)
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return res; // Didn't find, return org string
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if (!--count)
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{
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tmp_value.set(*res,0,offset);
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break;
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}
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}
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}
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else
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{
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/*
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Negative index, start counting at the end
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*/
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for (offset=res->length(); offset ;)
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{
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/*
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this call will result in finding the position pointing to one
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address space less than where the found substring is located
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in res
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*/
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if ((int) (offset= res->strrstr(*delimiter, offset)) < 0)
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return res; // Didn't find, return org string
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/*
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At this point, we've searched for the substring
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the number of times as supplied by the index value
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*/
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if (!++count)
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{
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offset+= delimiter_length;
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tmp_value.set(*res,offset,res->length()- offset);
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break;
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}
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}
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}
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}
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/*
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We always mark tmp_value as const so that if val_str() is called again
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on this object, we don't disrupt the contents of tmp_value when it was
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derived from another String.
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*/
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tmp_value.mark_as_const();
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return (&tmp_value);
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}
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} /* namespace drizzled */
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