BIT field woes

* get_rec_bits() was always reading two bytes, even if the bit field contained only of one byte * In various places the code used field->pack_length() bytes starting from field->ptr, while it should be field->pack_length_in_rec() * Field_bit::key_cmp and Field_bit::cmp_max passed field_length as an argument to memcmp(), but field_length is the number of bits!

Author: vuvova

include/my_compare.h

@@ -91,17 +91,19 @@ typedef struct st_HA_KEYSEG	/* Key-portion */
 
 #define size_to_store_key_length(length) ((length) < 255 ? 1 : 3)
 
-#define get_rec_bits(bit_ptr, bit_ofs, bit_len) \
- (((((uint16) (bit_ptr)[1] << 8) | (uint16) (bit_ptr)[0]) >> (bit_ofs)) & \
- ((1 << (bit_len)) - 1))
-
-#define set_rec_bits(bits, bit_ptr, bit_ofs, bit_len) \
-{ \
- (bit_ptr)[0]= ((bit_ptr)[0] & ~(((1 << (bit_len)) - 1) << (bit_ofs))) | \
- ((bits) << (bit_ofs)); \
- if ((bit_ofs) + (bit_len) > 8) \
- (bit_ptr)[1]= ((bit_ptr)[1] & ~((1 << ((bit_len) - 8 + (bit_ofs))) - 1)) | \
- ((bits) >> (8 - (bit_ofs))); \
+static inline uint16 get_rec_bits(const uchar *ptr, uchar ofs, uint len)
+{
+ uint16 val= ptr[0];
+ if (ofs + len > 8)
+ val|= (uint16)(ptr[1]) << 8;
+ return (val >> ofs) & ((1 << len) - 1);
+}
+
+static inline void set_rec_bits(uint16 bits, uchar *ptr, uchar ofs, uint len)
+{
+ ptr[0]= (ptr[0] & ~(((1 << len) - 1) << ofs)) | (bits << ofs);
+ if (ofs + len > 8)
+ ptr[1]= (ptr[1] & ~((1 << (len - 8 + ofs)) - 1)) | (bits >> (8 - ofs));
 }
 
 #define clr_rec_bits(bit_ptr, bit_ofs, bit_len) \

sql/field.cc

@@ -1758,7 +1758,7 @@ uint Field::fill_cache_field(CACHE_FIELD *copy)
 {
  uint store_length;
  copy->str= ptr;
- copy->length= pack_length();
+ copy->length= pack_length_in_rec();
  copy->field= this;
  if (flags & BLOB_FLAG)
  {
@@ -8422,7 +8422,7 @@ int Field_bit::cmp_max(const uchar *a, const uchar *b, uint max_len)
  if ((flag= (int) (bits_a - bits_b)))
  return flag;
  }
- return memcmp(a, b, field_length);
+ return memcmp(a, b, bytes_in_rec);
 }
 
 
@@ -8437,7 +8437,7 @@ int Field_bit::key_cmp(const uchar *str, uint length)
  str++;
  length--;
  }
- return memcmp(ptr, str, length);
+ return memcmp(ptr, str, bytes_in_rec);
 }
 
 

sql/field_conv.cc

@@ -589,7 +589,7 @@ void Copy_field::set(uchar *to,Field *from)
 {
  from_ptr=from->ptr;
  to_ptr=to;
- from_length=from->pack_length();
+ from_length=from->pack_length_in_rec();
  if (from->maybe_null())
  {
  from_null_ptr=from->null_ptr;
@@ -640,9 +640,9 @@ void Copy_field::set(Field *to,Field *from,bool save)
  from_field=from;
  to_field=to;
  from_ptr=from->ptr;
- from_length=from->pack_length();
+ from_length=from->pack_length_in_rec();
  to_ptr= to->ptr;
- to_length=to_field->pack_length();
+ to_length=to_field->pack_length_in_rec();
 
  // set up null handling
  from_null_ptr=to_null_ptr=0;

sql/sql_join_cache.cc

@@ -394,7 +394,7 @@ void JOIN_CACHE::create_flag_fields()
  TABLE *table= tab->table;
 
  /* Create a field for the null bitmap from table if needed */
- if (tab->used_null_fields || tab->used_uneven_bit_fields) 
+ if (tab->used_null_fields || tab->used_uneven_bit_fields)
  length+= add_flag_field_to_join_cache(table->null_flags,
  table->s->null_bytes,
  &copy);

sql/sql_select.cc

@@ -15537,7 +15537,7 @@ create_tmp_table(THD *thd, TMP_TABLE_PARAM *param, List<Item> &fields,
  else
  {
  field->set_notnull();
- memcpy(field->ptr, orig_field->ptr, field->pack_length());
+ memcpy(field->ptr, orig_field->ptr, field->pack_length_in_rec());
  }
  orig_field->move_field_offset(-diff); // Back to record[0]
  }