Regarding the correct and best way to fetching a tablename in contrib module

Hi ,

I have developed a new data type in PostgreSQL. The handler associated with
this data type is written in C language. This handler encrypts the column
data. I need help on figuring out how to get the table name when my
handler code is called during CRUD and Alter table operations.

let me elaborate a bit about the things i am gonna do here , So the thing
is i am developing a contrib module and wants to capture table name inside
that contrib module .

question:

1. Is there any way to capture a table name during CRUD and alter table ?
I have seen some of the triggers but not able to make it (i don't thing
there is any create table trigger exist ). in case If it is possible tell
me a way to achieve it.

2. I though of extracting meta-data using pg_class but not helping it seems
because i have to give explicitly a rel-name(table-name) in where clause
do you think any other way to achieve it ? please elaborate if any and
please let me know.

3. Is there any callback functions available so that i can call those
callback functions inside a code and if yes at what level we get tablename
attached with new datatype .

Here is some example which will make you understand a bit about the things
i am gonna do .

create table new_table(name varchar , newdata newdatatype) ;

insert into new_table values('abcdefghijkl' , '5004');

create table new_table1(name1 varchar , newdata newdatatype ) ;

insert into new_table1 values('mnopqrst' , 'abcde');

So my extension should extact a tablename ,means i should know tablename
with the built-in datatype I have declared .

here what i expect as a output :

create extension table_name-extract;

select extract_tablename();

table-name datatype-name

new_table newdatatype
new_table1 newdatatype

extract_tablename : this function should give me a table name with new data
type inside contrib module so that i can use in the extension .

Any help would be much appropriated .

Thanks and Regards,
Gaurav Mishra