Commit 26373380 authored by unknown's avatar unknown
Browse files

fixed substring() length calculation in case of constant negative argument (BUG#10269) 


mysql-test/r/func_str.result:
  Correct length reporting from substring()
mysql-test/t/func_str.test:
  Correct length reporting from substring()
sql/item_strfunc.cc:
  fixed substring() length calculation in case of constant negative argument
parent dadf91f0

mysql-test/r/func_str.result

+15 −0
Original line number Diff line number Diff line
@@ -800,3 +800,18 @@ SELECT * FROM t1, t2 WHERE num=substring(str from 1 for 6); 
str	num

notnumber	0

DROP TABLE t1,t2;

create table t1 (b varchar(5));

insert t1 values ('ab'), ('abc'), ('abcd'), ('abcde');

select *,substring(b,1),substring(b,-1),substring(b,-2),substring(b,-3),substring(b,-4),substring(b,-5) from t1;

b	substring(b,1)	substring(b,-1)	substring(b,-2)	substring(b,-3)	substring(b,-4)	substring(b,-5)

ab	ab	b	ab			

abc	abc	c	bc	abc		

abcd	abcd	d	cd	bcd	abcd	

abcde	abcde	e	de	cde	bcde	abcde

select * from (select *,substring(b,1),substring(b,-1),substring(b,-2),substring(b,-3),substring(b,-4),substring(b,-5) from t1) t;

b	substring(b,1)	substring(b,-1)	substring(b,-2)	substring(b,-3)	substring(b,-4)	substring(b,-5)

ab	ab	b	ab			

abc	abc	c	bc	abc		

abcd	abcd	d	cd	bcd	abcd	

abcde	abcde	e	de	cde	bcde	abcde

drop table t1;

mysql-test/t/func_str.test

+9 −0
Original line number Diff line number Diff line
@@ -541,3 +541,12 @@ SELECT * FROM t1, t2 WHERE num=str; 
SELECT * FROM t1, t2 WHERE num=substring(str from 1 for 6);



DROP TABLE t1,t2;



#

# Correct length reporting from substring() (BUG#10269)

#

create table t1 (b varchar(5));

insert t1 values ('ab'), ('abc'), ('abcd'), ('abcde');

select *,substring(b,1),substring(b,-1),substring(b,-2),substring(b,-3),substring(b,-4),substring(b,-5) from t1;

select * from (select *,substring(b,1),substring(b,-1),substring(b,-2),substring(b,-3),substring(b,-4),substring(b,-5) from t1) t;

drop table t1;

sql/item_strfunc.cc

+2 −1
Original line number Diff line number Diff line
@@ -1065,7 +1065,8 @@ void Item_func_substr::fix_length_and_dec() 
  collation.set(args[0]->collation);

  if (args[1]->const_item())

  {

    int32 start=(int32) args[1]->val_int()-1;

    int32 start= (int32) args[1]->val_int();

    start= (int32)((start < 0) ? max_length + start : start - 1);

    if (start < 0 || start >= (int32) max_length)

      max_length=0; /* purecov: inspected */

    else