check-part ( header trailer part bytes -- )

Vocabulary

yenc.private

Inputs

header	an object
trailer	an object
part	an object
bytes	an object

Outputs

None

Definition

USING: assocs kernel math sequences yenc ;

IN: yenc.private

:: check-part ( header trailer part bytes -- )
    header "part" metadata-number :> number number 0 >
    [ "Invalid part number" invalid-yenc ] unless
    number trailer "part" metadata-number check-size
    "total" header at [
        drop header "total" metadata-number
        :> total number total <=
        [ "Invalid part count" invalid-yenc ] unless
        "total" trailer key?
        [ total trailer "total" metadata-number check-size ]
        when
    ] when* part "begin" metadata-number
    :> first part "end" metadata-number
    :> last header "size" metadata-number :> size first 1 >=
    last first >= and last size <= and
    [ "Invalid part range" invalid-yenc ] unless last first -
    1 + bytes length check-size "pcrc32" trailer key?
    [ "Missing part CRC32" invalid-yenc ] unless
    bytes trailer "pcrc32" check-crc first 1 = last size = and
    [ bytes trailer "crc32" check-crc ] when ;