diff options
Diffstat (limited to 'sql/field.cc')
| -rw-r--r-- | sql/field.cc | 136 |
1 files changed, 136 insertions, 0 deletions
diff --git a/sql/field.cc b/sql/field.cc index 460a3bd514b..e85903d76c6 100644 --- a/sql/field.cc +++ b/sql/field.cc @@ -1273,6 +1273,37 @@ out_of_range: return 1; } + +/** + @brief + Determine the relative position of the field value in a numeric interval + + @details + The function returns a double number between 0.0 and 1.0 as the relative + position of the value of the this field in the numeric interval of [min,max]. + If the value is not in the interval the the function returns 0.0 when + the value is less than min, and, 1.0 when the value is greater than max. + + @param min value of the left end of the interval + @param max value of the right end of the interval + + @return + relative position of the field value in the numeric interval [min,max] +*/ + +double Field_num::pos_in_interval(Field *min, Field *max) +{ + double n, d; + n= val_real() - min->val_real(); + if (n < 0) + return 0.0; + d= max->val_real() - min->val_real(); + if (d <= 0) + return 1.0; + return min(n/d, 1.0); +} + + /** Process decimal library return codes and issue warnings for overflow and truncation. @@ -1344,6 +1375,8 @@ Field::Field(uchar *ptr_arg,uint32 length_arg,uchar *null_ptr_arg, comment.length=0; field_index= 0; is_stat_field= FALSE; + cond_selectivity= 1.0; + next_equal_field= NULL; } @@ -6165,6 +6198,79 @@ int Field_str::store(double nr) return store(buff, length, &my_charset_numeric); } +static +inline ulonglong char_prefix_to_ulonglong(uchar *src) +{ + uint sz= sizeof(ulonglong); + for (uint i= 0; i < sz/2; i++) + { + uchar tmp= src[i]; + src[i]= src[sz-1-i]; + src[sz-1-i]= tmp; + } + return uint8korr(src); +} + +/** + @brief + Determine the relative position of the field value in a string interval + + @details + The function returns a double number between 0.0 and 1.0 as the relative + position of the value of the this field in the string interval of [min,max]. + If the value is not in the interval the the function returns 0.0 when + the value is less than min, and, 1.0 when the value is greater than max. + + @note + To calculate the relative position of the string value v in the interval + [min, max] the function first converts the beginning of these three + strings v, min, max into the strings that are used for byte comparison. + For each string not more sizeof(ulonglong) first bytes are taken + from the result of conversion. Then these bytes are interpreted as the + big-endian representation of an ulonglong integer. The values of these + integer numbers obtained for the strings v, min, max are used to calculate + the position of v in [min,max] in the same way is it's done for numeric + fields (see Field_num::pos_in_interval). + + @todo + Improve the procedure for the case when min and max have the same + beginning + + @param min value of the left end of the interval + @param max value of the right end of the interval + + @return + relative position of the field value in the string interval [min,max] +*/ + +double Field_str::pos_in_interval(Field *min, Field *max) +{ + uchar mp_prefix[sizeof(ulonglong)]; + uchar minp_prefix[sizeof(ulonglong)]; + uchar maxp_prefix[sizeof(ulonglong)]; + ulonglong mp, minp, maxp; + my_strnxfrm(charset(), mp_prefix, sizeof(mp), + ptr + length_size(), + data_length()); + my_strnxfrm(charset(), minp_prefix, sizeof(minp), + min->ptr + length_size(), + min->data_length()); + my_strnxfrm(charset(), maxp_prefix, sizeof(maxp), + max->ptr + length_size(), + max->data_length()); + mp= char_prefix_to_ulonglong(mp_prefix); + minp= char_prefix_to_ulonglong(minp_prefix); + maxp= char_prefix_to_ulonglong(maxp_prefix); + double n, d; + n= mp - minp; + if (n < 0) + return 0.0; + d= maxp - minp; + if (d <= 0) + return 1.0; + return min(n/d, 1.0); +} + uint Field::is_equal(Create_field *new_field) { @@ -8376,6 +8482,36 @@ my_decimal *Field_bit::val_decimal(my_decimal *deciaml_value) } +/** + @brief + Determine the relative position of the field value in a bit interval + + @details + The function returns a double number between 0.0 and 1.0 as the relative + position of the value of the this field in the bit interval of [min,max]. + If the value is not in the interval the the function returns 0.0 when + the value is less than min, and, 1.0 when the value is greater than max. + + @param min value of the left end of the interval + @param max value of the right end of the interval + + @return + relative position of the field value in the bit interval [min,max] +*/ + +double Field_bit::pos_in_interval(Field *min, Field *max) +{ + double n, d; + n= val_real() - min->val_real(); + if (n < 0) + return 0.0; + d= max->val_real() - min->val_real(); + if (d <= 0) + return 1.0; + return min(n/d, 1.0); +} + + /* Compare two bit fields using pointers within the record. SYNOPSIS |