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Bug #24947: REPEAT function returns NULL when passed a field as the count parameter

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Handling of large signed/unsigned values was not consistent, so some string functions could return bogus results.
The current fix is to simply patch up the val_str() methods for those string items.
It would be good clean this code up in general, to make similar problems much harder to make.  This is left as an exercise for the reader.
This commit is contained in:
tsmith/tim@siva.hindu.god
2006-12-19 15:54:12 -07:00
parent 3cc1a4251a
commit 2bc45899c0
3 changed files with 40 additions and 21 deletions
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12
mysql-test/r/func_str.result
View File

@ -1916,4 +1916,16 @@ CHAR(0xff,0x8f USING utf8) IS NULL
Warnings:
Error 1300 Invalid utf8 character string: 'FF8F'
SET SQL_MODE=@orig_sql_mode;
select substring('abc', cast(2 as unsigned int));
substring('abc', cast(2 as unsigned int))
bc
select repeat('a', cast(2 as unsigned int));
repeat('a', cast(2 as unsigned int))
aa
select rpad('abc', cast(5 as unsigned integer), 'x');
rpad('abc', cast(5 as unsigned integer), 'x')
abcxx
select lpad('abc', cast(5 as unsigned integer), 'x');
lpad('abc', cast(5 as unsigned integer), 'x')
xxabc
End of 5.0 tests

8
mysql-test/t/func_str.test
View File

@ -991,5 +991,13 @@ SELECT CHAR(0xff,0x8f USING utf8) IS NULL;
SET SQL_MODE=@orig_sql_mode;
#
# Bug #24947: problem with some string function with unsigned int parameters
#
select substring('abc', cast(2 as unsigned int));
select repeat('a', cast(2 as unsigned int));
select rpad('abc', cast(5 as unsigned integer), 'x');
select lpad('abc', cast(5 as unsigned integer), 'x');
--echo End of 5.0 tests

41
sql/item_strfunc.cc
View File

@ -1166,7 +1166,8 @@ String *Item_func_substr::val_str(String *str)
/* if "unsigned_flag" is set, we have a *huge* positive number. */
/* Assumes that the maximum length of a String is < INT_MAX32. */
if ((args[1]->unsigned_flag) || (start < INT_MIN32) || (start > INT_MAX32))
if ((!args[1]->unsigned_flag && (start < INT_MIN32 || start > INT_MAX32)) ||
(args[1]->unsigned_flag && ((ulonglong) start > INT_MAX32)))
return &my_empty_string;
start= ((start < 0) ? res->numchars() + start : start - 1);
@ -2227,25 +2228,23 @@ String *Item_func_repeat::val_str(String *str)
uint length,tot_length;
char *to;
/* must be longlong to avoid truncation */
longlong tmp_count= args[1]->val_int();
long count= (long) tmp_count;
longlong count= args[1]->val_int();
String *res= args[0]->val_str(str);
/* Assumes that the maximum length of a String is < INT_MAX32. */
/* Bounds check on count: If this is triggered, we will error. */
if ((tmp_count > INT_MAX32) || args[1]->unsigned_flag)
count= INT_MAX32;
if (args[0]->null_value || args[1]->null_value)
goto err; // string and/or delim are null
null_value= 0;
if ((tmp_count <= 0) && !args[1]->unsigned_flag) // For nicer SQL code
if ((count <= 0) && !args[1]->unsigned_flag) // For nicer SQL code
return &my_empty_string;
/* Assumes that the maximum length of a String is < INT_MAX32. */
/* Bounds check on count: If this is triggered, we will error. */
if ((ulonglong) count > INT_MAX32)
count= INT_MAX32;
if (count == 1) // To avoid reallocs
return res;
length=res->length();
// Safe length check
if (length > current_thd->variables.max_allowed_packet/count)
if (length > current_thd->variables.max_allowed_packet / (uint) count)
{
push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
ER_WARN_ALLOWED_PACKET_OVERFLOWED,
@ -2319,15 +2318,14 @@ String *Item_func_rpad::val_str(String *str)
String *res= args[0]->val_str(str);
String *rpad= args[2]->val_str(&rpad_str);
/* Assumes that the maximum length of a String is < INT_MAX32. */
/* Set here so that rest of code sees out-of-bound value as such. */
if ((count > INT_MAX32) || args[1]->unsigned_flag)
count= INT_MAX32;
if (!res || args[1]->null_value || !rpad || count < 0)
if (!res || args[1]->null_value || !rpad ||
((count < 0) && !args[1]->unsigned_flag))
goto err;
null_value=0;
/* Assumes that the maximum length of a String is < INT_MAX32. */
/* Set here so that rest of code sees out-of-bound value as such. */
if ((ulonglong) count > INT_MAX32)
count= INT_MAX32;
if (count <= (res_char_length= res->numchars()))
{ // String to pad is big enough
res->length(res->charpos((int) count)); // Shorten result if longer
@ -2421,14 +2419,15 @@ String *Item_func_lpad::val_str(String *str)
String *res= args[0]->val_str(&tmp_value);
String *pad= args[2]->val_str(&lpad_str);
if (!res || args[1]->null_value || !pad ||
((count < 0) && !args[1]->unsigned_flag))
goto err;
null_value=0;
/* Assumes that the maximum length of a String is < INT_MAX32. */
/* Set here so that rest of code sees out-of-bound value as such. */
if ((count > INT_MAX32) || args[1]->unsigned_flag)
if ((ulonglong) count > INT_MAX32)
count= INT_MAX32;
if (!res || args[1]->null_value || !pad || count < 0)
goto err;
null_value=0;
res_char_length= res->numchars();
if (count <= res_char_length)