1
/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
2
* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
4
* Copyright (C) 2008 Sun Microsystems
6
* This program is free software; you can redistribute it and/or modify
7
* it under the terms of the GNU General Public License as published by
8
* the Free Software Foundation; version 2 of the License.
10
* This program is distributed in the hope that it will be useful,
11
* but WITHOUT ANY WARRANTY; without even the implied warranty of
12
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13
* GNU General Public License for more details.
15
* You should have received a copy of the GNU General Public License
16
* along with this program; if not, write to the Free Software
17
* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
22
#include <drizzled/function/str/substr.h>
31
String *Item_func_substr::val_str(String *str)
34
String *res = args[0]->val_str(str);
35
/* must be int64_t to avoid truncation */
36
int64_t start= args[1]->val_int();
37
/* Assumes that the maximum length of a String is < INT32_MAX. */
38
/* Limit so that code sees out-of-bound value properly. */
39
int64_t length= arg_count == 3 ? args[2]->val_int() : INT32_MAX;
42
if ((null_value=(args[0]->null_value || args[1]->null_value ||
43
(arg_count == 3 && args[2]->null_value))))
46
/* Negative or zero length, will return empty string. */
47
if ((arg_count == 3) && (length <= 0) &&
48
(length == 0 || !args[2]->unsigned_flag))
49
return &my_empty_string;
51
/* Assumes that the maximum length of a String is < INT32_MAX. */
52
/* Set here so that rest of code sees out-of-bound value as such. */
53
if ((length <= 0) || (length > INT32_MAX))
56
/* if "unsigned_flag" is set, we have a *huge* positive number. */
57
/* Assumes that the maximum length of a String is < INT32_MAX. */
58
if ((!args[1]->unsigned_flag && (start < INT32_MIN || start > INT32_MAX)) ||
59
(args[1]->unsigned_flag && ((uint64_t) start > INT32_MAX)))
60
return &my_empty_string;
62
start= ((start < 0) ? res->numchars() + start : start - 1);
63
start= res->charpos((int) start);
64
if ((start < 0) || ((uint) start + 1 > res->length()))
65
return &my_empty_string;
67
length= res->charpos((int) length, (uint32_t) start);
68
tmp_length= res->length() - start;
69
length= min(length, tmp_length);
71
if (!start && (int64_t) res->length() == length)
73
tmp_value.set(*res, (uint32_t) start, (uint32_t) length);
77
void Item_func_substr::fix_length_and_dec()
79
max_length=args[0]->max_length;
81
collation.set(args[0]->collation);
82
if (args[1]->const_item())
84
int32_t start= (int32_t) args[1]->val_int();
86
max_length= ((uint)(-start) > max_length) ? 0 : (uint)(-start);
88
max_length-= min((uint)(start - 1), max_length);
90
if (arg_count == 3 && args[2]->const_item())
92
int32_t length= (int32_t) args[2]->val_int();
96
set_if_smaller(max_length,(uint) length);
98
max_length*= collation.collation->mbmaxlen;
102
void Item_func_substr_index::fix_length_and_dec()
104
max_length= args[0]->max_length;
106
if (agg_arg_charsets(collation, args, 2, MY_COLL_CMP_CONV, 1))
111
String *Item_func_substr_index::val_str(String *str)
114
String *res= args[0]->val_str(str);
115
String *delimiter= args[1]->val_str(&tmp_value);
116
int32_t count= (int32_t) args[2]->val_int();
119
if (args[0]->null_value || args[1]->null_value || args[2]->null_value)
120
{ // string and/or delim are null
125
uint32_t delimiter_length= delimiter->length();
126
if (!res->length() || !delimiter_length || !count)
127
return &my_empty_string; // Wrong parameters
129
res->set_charset(collation.collation);
131
if (use_mb(res->charset()))
133
const char *ptr= res->ptr();
134
const char *strend= ptr+res->length();
135
const char *end= strend-delimiter_length+1;
136
const char *search= delimiter->ptr();
137
const char *search_end= search+delimiter_length;
138
int32_t n=0,c=count,pass;
140
for (pass=(count>0);pass<2;++pass)
147
i=(char*) ptr+1; j=(char*) search+1;
148
while (j != search_end)
149
if (*i++ != *j++) goto skip;
151
else if (!--c) break;
152
ptr+= delimiter_length;
156
if ((l=my_ismbchar(res->charset(), ptr,strend))) ptr+=l;
158
} /* either not found or got total number when count<0 */
159
if (pass == 0) /* count<0 */
162
if (c<=0) return res; /* not found, return original string */
167
if (c) return res; /* Not found, return original string */
168
if (count>0) /* return left part */
170
tmp_value.set(*res,0,(ulong) (ptr-res->ptr()));
172
else /* return right part */
174
ptr+= delimiter_length;
175
tmp_value.set(*res,(ulong) (ptr-res->ptr()), (ulong) (strend-ptr));
183
{ // start counting from the beginning
184
for (offset=0; ; offset+= delimiter_length)
186
if ((int) (offset= res->strstr(*delimiter, offset)) < 0)
187
return res; // Didn't find, return org string
190
tmp_value.set(*res,0,offset);
198
Negative index, start counting at the end
200
for (offset=res->length(); offset ;)
203
this call will result in finding the position pointing to one
204
address space less than where the found substring is located
207
if ((int) (offset= res->strrstr(*delimiter, offset)) < 0)
208
return res; // Didn't find, return org string
210
At this point, we've searched for the substring
211
the number of times as supplied by the index value
215
offset+= delimiter_length;
216
tmp_value.set(*res,offset,res->length()- offset);
223
We always mark tmp_value as const so that if val_str() is called again
224
on this object, we don't disrupt the contents of tmp_value when it was
225
derived from another String.
227
tmp_value.mark_as_const();
231
} /* namespace drizzled */
added
removed
drizzled/function/str/substr.cc
