itemsubgroup.dbss

Binary layout, intrinsic member variants, subgroup semantics, and exact snapshot evidence for the itemsubgroup.dbss decoder in calpheonlabs.

Investigation status

Status	Value
Evidence state	Reconciled
Coverage	100%
Iteration	5
Last reviewed	2026-07-31
Captures examined	Build 2938; `Paz/pad00000.meta` SHA-256 `b7eefe6059818f84c0545f10020fe93bd3bd5d0647e043120caf78726ccafe8f`
Primary bytes	13,275,148; SHA-256 `2d004d69f7142f5d9c9ae932986ff9aa4458d5d1d8e8f7d3a5895ea4ae50ef47`
Snapshot proof	16,428 groups / 96,144 members; normalized SHA-256 `b73281a8809f6f3b134bbdf84ac5bd3f786d96deed960c2ff8b1a5889d0e903b`
Variant coverage	75,061 `empty`; 20,835 `sentinel`; 247 `trade`; 1 `single_flag`
Decoder	`packages/scraper/src/tables/itemsubgroup.dbss.ts`
Remaining blockers	None

See Decoder methodology. The former itemsubgroupoffset.dbss dependency is now migration evidence only: embedded counts and fixed 135-byte members frame this decoder intrinsically.

Field ledger

Field/path	Offset and width	Representation	Claimed meaning	Physical confidence	Representation confidence	Semantic confidence	Evidence	Status
`groupCount`, `groups[]`	file `+0`, 4; variable groups	retained `u32`, counted array	Subgroup count and physical groups	Certain	Certain	High	16,428 groups consume through EOF; identifiers are checked unique	Closed
`groups[].groupId`	group `+0`, 4	`u32`	Item-subgroup identifier	Certain	Certain	Certain	Main-group references and all offset-directory identities agree	Closed
`groups[].reserved`	group `+4..+13`, 10	zero-checked `bytes(10).reserved()`	Byte-only empty header range	Certain	Certain	Unknown	Explicitly validated, consumed, and intentionally omitted	Closed
`groups[].memberCount`, `members[]`	group `+14`, 4; then 135 each	retained `u32`, counted union	Member count and ordered members	Certain	Certain	Certain	96,144 members derive every group span and match the offset evidence exactly	Closed
all `type`	derived, 0 bytes	`literal` from ordered union	Physical member layout	Certain	Certain	High	Intrinsic markers and zero regions select all four observed branches	Closed
all `itemId`	member `+0`, 3	`u24`	Item-family identifier	Certain	Certain	Certain	Low packed bytes resolve exact item identities	Closed
all `enhancementLevel`	member `+3`, 1	`u8`	Enhancement discriminator	Certain	Certain	Certain	High packed byte resolves exact item/enhancement identities	Closed
all `reserved04`	member `+4..+15`, 12	zero-checked `bytes(12).reserved()`	Byte-only empty range	Certain	Certain	Unknown	Validated in every branch and omitted only as bytes	Closed
all `field46`, `field47`	member `+46`, 1; `+47`, 1	`u8`	Neutral controls	Certain	Certain	Unknown	Full captured values retained without former Boolean/domain restrictions	Closed
all `reserved48`	member `+48..+50`, 3	zero-checked `bytes(3).reserved()`	Byte-only alignment	Certain	Certain	Unknown	Validated in all 96,144 members	Closed
all `field51`	member `+51`, 4	`u32`	Neutral control	Certain	Certain	Unknown	Exact scalar retained; no universal chance/rate interpretation survives	Closed
`empty.auxiliary`, `empty.reserved55`	`+16..+45`, 30; `+55..+134`, 80	zero-checked reserved bytes	Empty-layout regions	Certain	Certain	Unknown	75,061 members select this branch only when both ranges are empty	Closed
`single_flag.auxiliary.flag`	member `+16`, 1	nonzero-checked `u8`	Neutral auxiliary discriminator	Certain	Certain	Unknown	The sole captured member contains the only nonempty byte in this layout	Closed
`single_flag.auxiliary.reserved`, `reserved55`	`+17..+45`, 29; `+55..+134`, 80	zero-checked reserved bytes	Empty-layout regions	Certain	Certain	Unknown	Intrinsic zero checks distinguish the branch without an external type code	Closed
`sentinel.auxiliary.field16`	member `+16`, 2	retained `u16().is(0)`	Structural zero word	Certain	Certain	Unknown	Required by all 20,835 sentinel members and retained as a scalar	Closed
`sentinel.auxiliary.sentinels`	member `+18..+33`, 16	eight retained `u16().is(0xffff)`	Unset-slot sentinel pattern	Certain	Certain	Unknown	Exhaustive intrinsic branch evidence	Closed
`sentinel.auxiliary.signedValue34`	member `+34`, 2	`i16`	Neutral signed value	Certain	Certain	Unknown	Both signs and zero are retained without a captured allow-list	Closed
`sentinel.auxiliary.signedValue36`	member `+36`, 2	`i16` plus relation check	Sign extension of `signedValue34`	Certain	Certain	Certain	Exact sign extension across every sentinel member	Closed
`sentinel.auxiliary.byte38`	member `+38`, 1	retained `u8().is(0)`	Structural zero byte	Certain	Certain	Unknown	Required and retained rather than hidden	Closed
`sentinel.auxiliary.reserved`, `reserved55`	`+39..+45`, 7; `+55..+134`, 80	zero-checked reserved bytes	Empty-layout regions	Certain	Certain	Unknown	Explicitly consumed and intentionally omitted	Closed
`trade.auxiliary.marker`	member `+16`, 2	retained `u16().is(0x0100)`	Trade-family discriminator	Certain	Certain	High	Marker pairs with `tradeMarker` in all 247 trade members	Closed
`trade.auxiliary.sentinels`	member `+18..+33`, 16	eight retained `u16().is(0xffff)`	Unset-slot sentinel pattern	Certain	Certain	Unknown	Exhaustive intrinsic branch evidence	Closed
`trade.auxiliary.field34`	member `+34`, 4	retained `u32().is(0)`	Structural zero word	Certain	Certain	Unknown	Required and retained as a non-byte scalar	Closed
`trade.auxiliary.variantCode`	member `+38`, 1	`u8`	Neutral layout variant	Certain	Certain	Unknown	Full domain retained without a captured allow-list	Closed
`trade.auxiliary.reserved`	member `+39..+45`, 7	zero-checked reserved bytes	Byte-only empty range	Certain	Certain	Unknown	Explicitly consumed and intentionally omitted	Closed
`trade.tradeMarker`	member `+55`, 2	retained `u16().is(0x0101)`	Trade-tail discriminator	Certain	Certain	High	Exact paired marker in every trade member	Closed
`trade.reserved57`	member `+57..+58`, 2	zero-checked reserved bytes	Byte-only alignment	Certain	Certain	Unknown	Explicitly consumed and intentionally omitted	Closed
`trade.baseValue64`	member `+59`, 8	`u64` transformed to decimal string	Base stored value	Certain	Certain	High	Full-width value retained losslessly; overlapping low/high aliases were intentionally removed	Closed
`trade.lowerValue64`	member `+67`, 8	`u64` transformed to decimal string	Lower stored band value	Certain	Certain	High	Full-width value agrees with the transformed reference for all 247 rows	Closed
`trade.upperValue64`	member `+75`, 8	`u64` transformed to decimal string	Upper stored band value	Certain	Certain	High	Full-width value agrees with the transformed reference for all 247 rows	Closed
`trade.signedValue64`	member `+83`, 8	`i64` transformed to decimal string	Neutral signed slot	Certain	Certain	Unknown	Signed full-width value retained without redundant word aliases	Closed
`trade.valueUnit64`	member `+91`, 8	`u64` transformed to decimal string	Stored base/100 value	Certain	Certain	High	`valueUnit64 * 100 === baseValue64` is checked on the full-width values	Closed
`trade.reserved99`	member `+99..+130`, 32	zero-checked reserved bytes	Byte-only empty range	Certain	Certain	Unknown	Explicitly consumed and intentionally omitted	Closed
`trade.field131`	member `+131`, 4	`u32`	Neutral final control	Certain	Certain	Unknown	Exact scalar retained with no speculative availability meaning	Closed
branch/member length validation	every member, 135	`.fixedLength(135)` and ordered `union`	Exact member consumption	Certain	Certain	Certain	Every present branch is exercised and full-table strict decode reaches EOF	Closed

Active assumptions

Findings

ID	Finding	Evidence	Schema/documentation impact	Status
ISG-01	Four layouts are intrinsically distinguishable without the offset directory.	Marker-bearing branches, sign-extension checks, and checked zero regions select all 96,144 members exactly.	Production uses an ordered BSD union: trade, sentinel, single flag, then empty.	Resolved
ISG-02	Packed item/enhancement identity is naturally `u24` plus `u8`.	Every member joins the item-enchant identity namespace and matches the former overlapping `u32` views.	Redundant packed-word aliases were removed from the transformed reference snapshot.	Resolved
ISG-03	The trade band is best retained as five full-width values.	All 247 rows preserve exact 64-bit values and the base/unit relation.	Decimal strings avoid JSON bigint loss while low/high word aliases are intentionally absent.	Resolved
ISG-04	The offset table is falsification evidence, not runtime framing.	Embedded group/member counts reproduce all 16,428 directory widths and strict decode consumes 13,275,148 bytes.	No production import, load, or join to `itemsubgroupoffset.dbss` remains.	Resolved