Reading deleted records - PageHeader v3

Hi,

So first I'm a pgsql hacker newbie and I've been reading up on the storage
structure:

http://www.postgresql.org/docs/8.2/interactive/storage-page-layout.html

I'm trying to recover deleted records from a page file (postgresql 8.2) :
i.e. base/dbId/20132

I am able to successfully read all the header data I need (PageHeaderData,
ItemIdData , HeapTupleHeaderData)

but I hit a wall when I try to start reading user data.

This has helped:

http://anoncvs.postgresql.org/cvsweb.cgi/pgsql/src/include/postgres.h?rev=1.
77;content-type=text%2Fplain

I've read and understood fairly well how varlena structures are stored
(plain, compressed, external/toast) but so far I can't seem to read a plain
inline value.

I think part of my problem is I haven't really understood what 'Then make
sure you have the right alignment' means.

My approach currently is:

After reading HeapTupleHeaderData (23 bytes), I advance another 4 bytes
(hoff) and try to read a 32 bit integer (first attribute).

I am expecting to get an integer value 1 but I get 512 .

Am I doing this wrong?

Could someone point me to the pgsql code pieces I should be looking at?

If useful, this is the information I have before reading the 'user data':

object(PostgreSQL_HeapTupleHeaderData)#14 (7) {

["xmin"]=>

string(5) "13824"

["xmax"]=>

string(1) "0"

["cid"]=>

string(1) "0"

["ctid"]=>

object(PostgreSQL_ItemPointerData)#16 (2) {

["blockId"]=>

string(1) "0"

["posId"]=>

int(0)

}

["infomask2"]=>

int(0)

["infomask"]=>

int(2)

["hoff"]=>

int(4)

}

object(PostgreSQL_Attribute)#7 (6) {

["name"]=>

string(7) "book_id"

["relid"]=>

int(20132)

["len"]=>

int(4)

["num"]=>

int(1)

["ndims"]=>

int(0)

["align"]=>

string(1) "i"

}

array(1) {

["book_id"]=>

int(512)

}