merge 5.0-bugteam to 5.1-bugteam

mysql-test/r/myisampack.result

@@ -54,3 +54,14 @@ test.t1	repair	error	Table 'test.t1' is read only
 Warnings:
 Error	1036	Table 't1' is read only
 drop table t1;
+#
+# BUG#41541 - Valgrind warnings on packed MyISAM table
+#
+CREATE TABLE  t1(f1 VARCHAR(200), f2 TEXT);
+INSERT INTO  t1 VALUES ('foo', 'foo1'), ('bar', 'bar1');
+FLUSH TABLE t1;
+# Compress the table using MYISAMPACK tool
+SELECT COUNT(*) FROM t1;
+COUNT(*)
+1024
+DROP TABLE t1;

mysql-test/t/myisampack.test

@@ -61,3 +61,23 @@ let $MYSQLD_DATADIR= `select @@datadir`;
 optimize table t1;
 repair table t1;
 drop table t1;
+
+--echo #
+--echo # BUG#41541 - Valgrind warnings on packed MyISAM table
+--echo #
+CREATE TABLE  t1(f1 VARCHAR(200), f2 TEXT);
+INSERT INTO  t1 VALUES ('foo', 'foo1'), ('bar', 'bar1');
+let $i=9;
+--disable_query_log
+while ($i)
+{
+ INSERT INTO t1 SELECT * FROM t1; 
+ dec $i; 
+}
+--enable_query_log
+FLUSH TABLE t1; 
+--echo # Compress the table using MYISAMPACK tool
+let $MYSQLD_DATADIR= `select @@datadir`;
+--exec $MYISAMPACK $MYSQLD_DATADIR/test/t1
+SELECT COUNT(*) FROM t1;
+DROP TABLE t1; 

storage/myisam/mi_packrec.c

@@ -1431,6 +1431,32 @@ static void fill_buffer(MI_BIT_BUFF *bit_buff)
     bit_buff->current_byte=0;
     return;
   }
+  else
+  {
+    uint len= 0;
+    uint i= 0;
+    /*
+      Check if the remaining buffer/record to read is less than the word size.
+      If so read byte by byte
+
+      Note: if this branch becomes a bottleneck it can be removed, assuming
+      that the second memory segment allocates 7 extra bytes (see
+      _mi_read_pack_info()).
+    */
+    len= bit_buff->end - bit_buff->pos;
+    if (len < (BITS_SAVED / 8))
+    {
+      bit_buff->current_byte= 0;
+      for (i=0 ; i < len ; i++)
+      {
+        bit_buff->current_byte+= (((uint) ((uchar) bit_buff->pos[len - i - 1]))
+                                                                    << (8 * i));
+      }
+      bit_buff->pos= bit_buff->end;
+      return;
+    }
+  }
+
 #if BITS_SAVED == 64
   bit_buff->current_byte=  ((((uint) ((uchar) bit_buff->pos[7]))) +
 			     (((uint) ((uchar) bit_buff->pos[6])) << 8) +