database/mariadb
1
0
Fork 0
mirror of https://github.com/MariaDB/server.git synced 2025-08-01 03:47:19 +03:00
Code Activity

A fix (bug #5497: COMPRESS() returns NULL for large strings).

Browse Source
This commit is contained in:
ram@gw.mysql.r18.ru
2004-09-13 18:43:59 +05:00
parent ca0fc0b4f4
commit a3a6b7fa25
3 changed files with 20 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
mysql-test/r/func_compress.result
View File

@ -68,3 +68,7 @@ Warnings:
Error 1259 ZLIB: Input data corrupted
Error 1256 Uncompressed data size too large; the maximum size is 1048576 (probably, length of uncompressed data was corrupted)
drop table t1;
set @@max_allowed_packet=1048576*100;
select length(compress(repeat('aaaaaaaaaa', 10000000)));
length(compress(repeat('aaaaaaaaaa', 10000000)))
97214

7
mysql-test/t/func_compress.test
View File

@ -35,3 +35,10 @@ select length(a) from t1;
select length(uncompress(a)) from t1;
drop table t1;
#
# Bug #5497: a problem with large strings
#
set @@max_allowed_packet=1048576*100;
select length(compress(repeat('aaaaaaaaaa', 10000000)));

12
sql/item_strfunc.cc
View File

@ -2723,12 +2723,18 @@ String *Item_func_compress::val_str(String *str)
compress(compress(compress(...)))
I.e. zlib give number 'at least'..
*/
ulong new_size= (ulong)((res->length()*120)/100)+12;
ulong new_size= res->length() + res->length() / 5 + 12;
// Will check new_size overflow: new_size <= res->length()
if (((uint32) new_size <= res->length()) ||
buffer.realloc((uint32) new_size + 4 + 1))
{
null_value= 1;
return 0;
}
buffer.realloc((uint32)new_size + 4 + 1);
Byte *body= ((Byte*)buffer.ptr()) + 4;
// As far as we have checked res->is_empty() we can use ptr()
if ((err= compress(body, &new_size,
(const Bytef*)res->ptr(), res->length())) != Z_OK)