fix for bug #1993 'bit functions do not return unsigned values'

introduced base class Item_func_bit for bit functions

mysql-test/r/func_op.result

@@ -7,3 +7,21 @@ select 1 | (1+1),5 & 3,bit_count(7) ;
 select 1 << 32,1 << 63, 1 << 64, 4 >> 2, 4 >> 63, 1<< 63 >> 60;
 1 << 32	1 << 63	1 << 64	4 >> 2	4 >> 63	1<< 63 >> 60
 4294967296	9223372036854775808	0	1	0	8
+select -1 | 0, -1 ^ 0, -1 & 0;
+-1 | 0	-1 ^ 0	-1 & 0
+18446744073709551615	18446744073709551615	0
+select -1 | 1, -1 ^ 1, -1 & 1;
+-1 | 1	-1 ^ 1	-1 & 1
+18446744073709551615	18446744073709551614	1
+select  1 | -1,  1 ^ -1,  1 & -1;
+1 | -1	1 ^ -1	1 & -1
+18446744073709551615	18446744073709551614	1
+select  0 | -1,  0 ^ -1,  0 & -1;
+0 | -1	0 ^ -1	0 & -1
+18446744073709551615	18446744073709551615	0
+select -1 >> 0, -1 << 0;
+-1 >> 0	-1 << 0
+18446744073709551615	18446744073709551615
+select -1 >> 1, -1 << 1;
+-1 >> 1	-1 << 1
+9223372036854775807	18446744073709551614

mysql-test/t/func_op.test

@@ -5,3 +5,12 @@
 select 1+1,1-1,1+1*2,8/5,8%5,mod(8,5),mod(8,5)|0,-(1+1)*-2;
 select 1 | (1+1),5 & 3,bit_count(7) ;
 select 1 << 32,1 << 63, 1 << 64, 4 >> 2, 4 >> 63, 1<< 63 >> 60;
+#
+# bug #1993: bit functions must be unsigned
+#
+select -1 | 0, -1 ^ 0, -1 & 0;
+select -1 | 1, -1 ^ 1, -1 & 1;
+select  1 | -1,  1 ^ -1,  1 & -1;
+select  0 | -1,  0 ^ -1,  0 & -1;
+select -1 >> 0, -1 << 0;
+select -1 >> 1, -1 << 1;

sql/item_func.h

@@ -642,23 +642,30 @@ class Item_func_find_in_set :public Item_int_func
   unsigned int size_of() { return sizeof(*this);}  
 };
 
+/* Base class for all bit functions: '~', '|', '^', '&', '>>', '<<' */
 
-class Item_func_bit_or :public Item_int_func
+class Item_func_bit: public Item_int_func
 {
 public:
-  Item_func_bit_or(Item *a,Item *b) :Item_int_func(a,b) {}
+  Item_func_bit(Item *a, Item *b) :Item_int_func(a, b) {}
+  Item_func_bit(Item *a) :Item_int_func(a) {}
+  void fix_length_and_dec() { unsigned_flag= 1; }
+};
+
+class Item_func_bit_or :public Item_func_bit
+{
+public:
+  Item_func_bit_or(Item *a, Item *b) :Item_func_bit(a, b) {}
   longlong val_int();
   const char *func_name() const { return "|"; }
-  void fix_length_and_dec() { unsigned_flag=1; }
 };
 
-class Item_func_bit_and :public Item_int_func
+class Item_func_bit_and :public Item_func_bit
 {
 public:
-  Item_func_bit_and(Item *a,Item *b) :Item_int_func(a,b) {}
+  Item_func_bit_and(Item *a, Item *b) :Item_func_bit(a, b) {}
   longlong val_int();
   const char *func_name() const { return "&"; }
-  void fix_length_and_dec() { unsigned_flag=1; }
 };
 
 class Item_func_bit_count :public Item_int_func
@@ -670,30 +677,28 @@ class Item_func_bit_count :public Item_int_func
   void fix_length_and_dec() { max_length=2; }
 };
 
-class Item_func_shift_left :public Item_int_func
+class Item_func_shift_left :public Item_func_bit
 {
 public:
-  Item_func_shift_left(Item *a,Item *b) :Item_int_func(a,b) {}
+  Item_func_shift_left(Item *a, Item *b) :Item_func_bit(a, b) {}
   longlong val_int();
   const char *func_name() const { return "<<"; }
-  void fix_length_and_dec() { unsigned_flag=1; }
 };
 
-class Item_func_shift_right :public Item_int_func
+class Item_func_shift_right :public Item_func_bit
 {
 public:
-  Item_func_shift_right(Item *a,Item *b) :Item_int_func(a,b) {}
+  Item_func_shift_right(Item *a, Item *b) :Item_func_bit(a, b) {}
   longlong val_int();
   const char *func_name() const { return ">>"; }
 };
 
-class Item_func_bit_neg :public Item_int_func
+class Item_func_bit_neg :public Item_func_bit
 {
 public:
-  Item_func_bit_neg(Item *a) :Item_int_func(a) {}
+  Item_func_bit_neg(Item *a) :Item_func_bit(a) {}
   longlong val_int();
   const char *func_name() const { return "~"; }
-  void fix_length_and_dec() { unsigned_flag=1; }
 };
 
 class Item_func_set_last_insert_id :public Item_int_func
@@ -1018,13 +1023,12 @@ enum Item_cast
 Item *create_func_cast(Item *a, Item_cast cast_type);
 
 
-class Item_func_bit_xor : public Item_int_func
+class Item_func_bit_xor : public Item_func_bit
 {
 public:
-  Item_func_bit_xor(Item *a,Item *b) :Item_int_func(a,b) {}
+  Item_func_bit_xor(Item *a, Item *b) :Item_func_bit(a, b) {}
   longlong val_int();
   const char *func_name() const { return "^"; }
-  void fix_length_xor_dec() { unsigned_flag=1; }
 };
 
 class Item_func_is_free_lock :public Item_int_func