How can i make a pl/sql function for BLOB datatype

Question

hi..anyone here who is very familiar about BLOB datatype. i have a COLUMN_ID, COLUMN_A in a certain TABLE_1. COLUMN_A is blob datatype that contains almost 250,000rows
SQL>select column_A from table_1 where column_id=1234567
column_A
00000001000000010000000606D4E833074B69EC06D4E91F074CO18406D50C58074C031E
how can i make a user-defined function to compute and convert this blob datatype into decimal length value. this hex value are points in the map.. the function must contain
1.get the length of a blob then
2.convert blob to variable hexadecimal characters by parsing it into 8
3.to_number function or other function used to convert haxadecimal characters to decimal numbers
4.phythagorean formula to compute length between two points. this is the formula i think LENGTH =
SQRT(power((coordinate_x-prev_coordinate_x),2)+power((coordinate_y-prev_y),2));
after this when i type this
SQL>select user_function(column_A) from table_1 where column_id=1234567
user_functions(column_A)
--output length will be in decimal value already
the function will goes like this
step1 is to get the blob length
00000001000000010000000606D4E833074B69EC06D4E91F074CO18406D50C58074C031E
step2 is parsing of data by eights
00000001 =>1
00000001 =>1
00000006 =>6 (number of coordinates)
06D4E833 => X1
074B69EC => Y1
06D4E91F => X2
074CO184 => Y2
06D50C58 => X3
074C031E => Y3
step3 to_number function used to convert hex char to decimal
step4 compute by phytagorean (NOTE ! when computing length the third parsed eight will tell how many coordinates are there..the number of coordinates is ranging from 2 up to E..above example shows 6 coordinates so it means
LENGTH1 =
SQRT(power((X2-X1),2)+power((Y2-Y1),2));
LENGTH2=
SQRT(power((X3-X2),2)+power((Y3-Y2),2));
TOTAL LENGTH=LENGTH1 + LENGTH2
thanks

Answer 1

its my first time to use that.There's got to be a first tiem for anything. Be brave.
btw if theres more easy suggestion pls feel free..Well of course the easiest solution would be if the calling program passed in the parameters as separate arguments instead of glomming them together in a string that has to be parsed. This sort of kluj really ought not to have survived into C21.
Cheers, APC