Key Word List

Key Words with Descriptions

Key Word

Description

ALSO

Chains together RETRIEVE, FORMAT or VERIFY statements

ALWAYS_ASK

Used in conjunction with the PARAMETER keyword. Forces the user to enter the parameter every time the decoder is loaded.

APPEND_ONLY

Used in conjunction with TABLE. Causes the protocol stack to automatically traverse to your protocols and use your custom decoders when relevant.

APPEND_AND_ OVERWRITE

Used in conjunction with TABLE. Causes the protocol stack to automatically traverse to your protocols but will overwrite table properties. Use with caution.

ASK_IF_NOT_ DEFINED

Used in conjunction with the PARAMETER keyword. Asks the user for the parameter the first time the decoder is loaded, and doesn't ask again after that.

BRANCH

Causes control to pass to one of several places depending on the results of the Branch method.

BYTE_STREAM_ FRAMER

Reference section keyword followed by a byte stream framer method. Works in a similar fashion to a frame recognizer, except that it operates only on the data found at the current layer.

COUNT

Used with REPEAT clauses to repeat the group X number of times.

DECODE

Begins the decoder.

DEFAULT

Specifies the default entry for tables.

ELSE_SKIP

Used with a Size method to skip a specified amount of data if a conditional fails. If the ELSE_SKIP is not present, no data is skipped.

END_MAIN_PATH

Ends the decoder. At this statement decoding of this layer stops.

ENDTABLE

Specifies the end of a table.

FIELD

The main component of the decoder.

FRAME_AFTER_ DECODING

Reference section keyword followed by a frame transformer method that processes the frame after it has been decoded.

FRAME_BEFORE_ DECODING

Reference section keyword followed by a frame transformer method that processes the frame before it is decoded.

FIXED

In a FIELD will return a fixed number of bit, bytes, or other units specified.

GROUP

Used to group together FIELDs for a variety of reasons. Groups can be the destination of a branch, they can have conditionals placed on them or REPEAT clauses such that the fields in the group are executed multiple times.

HOST_DATA_ORDER

Can be placed either after the decoder ID at the top of the decoder, in which case all fields are interpreted in host data order, or at the end of a field statement, in which case just that field is interpreted in host data order. See The Header Section for more information.

IF

Conditional. Used with Boolean methods.

IGNORE_BRANCH_ FIELDS

This lets you use a table across multiple decoders without bringing in all of the DecoderScript to satisfy the Branch fields in TABLEs.

IN_COLLAPSED

Places the results of the field just in the summary line of a collapsed protocol in the Protocol Navigator.

IN_SUMMARY

Places the results of the field in the Summary pane on the Frame Display and in the summary line of a collapsed protocol in the Protocol Navigator.

IN_SUMMARY_ONLY

Places the results of the field in just the Summary pane on the Frame Display

INCLUDE

Inserts the named file at this location in the decoder.

INCLUDE_IF_EXISTS

Inserts the named file at this location in the decoder if the file exists, otherwise it is not included.

INFO

Causes the field output to be displayed in an Information line at the top of the Decode pane in addition to its normal location in the decode.

LIST

Defines a list of legal values that a parameter can take. Used in conjunction with the PARAMETER keyword.

MARGIN_TEXT

Causes the field output to be appended to the margin text in the Protocol Navigator.

NETWORK_DATA_ ORDER

Can be placed either after the decoder ID at the top of the decoder, in which case all fields are interpreted in network data order, or at the end of a field statement, in which case just that field is interpreted in network data order. See The Header Section for more information.

NEVER_ASK

Used in conjunction with the PARAMETER keyword. Never asks the user for the parameter value. Useful when the parameter has a good default value that may need to be changed only rarely.

NEXT_PROTOCOL

Reference section keyword followed by a Next Protocol method. Determines the next protocol in the stack.

NEXT_PROTOCOL_ OFFSET

Reference section keyword followed by a Next Protocol Offset method. Determines the number of bytes between the end of the current layer and the beginning of the next.

NEXT_PROTOCOL_ SIZE

Reference section keyword followed by a Next Protocol Size method. Determines the size of the next layer in bytes.

NO_MOVE

Tells the protocol analyzer not to move the bit pointer after decoding the field.

NOT

Reverses the results of a Boolean or Verify method. Often used in IF clauses.

PARAMETER

Defines a runtime parameter for the decoder. Allows the user to give information to the decoder that can be used for decision making or for field definitions.

PAYLOAD_IS_BYTE_ STREAM

Reference section keyword. Tells the next protocol in the stack to treat the payload of all subsequent frames as a continuous byte stream. Used in conjunction with the BYTE_STREAM_FRAMER keyword.

POSTPROCESSING

Reference section keyword followed by a method that does things after the layer is decoded. Note that these methods cannot change the data in the frame.

PREPROCESSING

Reference section keyword followed by a method that does things before the layer is decoded. Note that these methods cannot change the data in the frame.

PROCESSING

Allows you to gain control when the frame is first compiled and is useful on frames larger than 64 bits. PROCESSING clauses can be strung together.

PRINT_IF

Followed by a Boolean method. Prints the value of the field in the Decode pane only if the method returns true.

RECOGNIZER

Reference section keyword. Identifier the frame recognizer for the protocol.

REPEAT

Followed by a SIZE, COUNT or UNTIL keyword. Used with groups to cause the group to be repeated.

RESERVED

Used with Size methods to skip a specified amount of data.

RETRIEVE

Used with Retrieve methods, which usually manipulate the contents of the field before displaying it.

SIZE

Followed by a Size method. Used with the REPEAT keyword on groups to repeat the group until the number of bits specified in the Size method have been used up.

START_BIT

Followed by a Start bit method to alter the location of the bit pointer.

STORE

Followed by a name. Stores the field contents under this name so other methods can reference it.

SUMMARY_ COLUMNS

Followed by a list of Summary Pane Column names and their default widths. Allows you to define the order of the Summary Pane entries.

SUPPRESS_DETAIL

Prevents the field from being displayed in the Decode pane.

SUPPRESS_IF_ VERIFIED

Prevents the field from being displayed in the Decode pane only if the Verify passes. The field is shown if the Verify fails.

TABLE

Begins a table.

TAG

Followed by a Tag method. Used to tag a field for filtering, tracking and other purposes.

TRUNCATED_FIELD_ OK

Suppresses an error if a group is truncated, usually an indication of a faulty decoder or damaged frame.

UNTIL

Followed by a Boolean method. Used with the REPEAT keyword on groups to repeat the group until the Boolean method returns true.

VERIFY

A clause placed at the end of FIELD statement to compare the field value with a constant using for example FieldIs or FielsIsBetween.