Svc::BufferRepeater: Buffer Repeater (Passive Component)

1. Introduction

The BufferRepeater component is designed to take in an Fw::buffer port call and repeat it to multiple output ports. New memory is allocated from a Svc::BufferManager and the data is copied to ensure that each downstream component has full ownership of its data. The original buffer is deallocated. Users call configure to set the response of the component when allocation requests fail.

2. Requirements

Name	Description	Validation
BUFFER_REPEATER_01	The buffer repeater shall accept incoming `Fw::Buffer` port calls	Unit Test
BUFFER_REPEATER_02	The buffer repeater shall copy the incoming data before each repeated send	Unit Test
BUFFER_REPEATER_03	The buffer repeater shall only send a copy to connected components	Unit Test
BUFFER_REPEATER_04	The buffer repeater shall have a configurable response to allocation failures	Unit Test

3. Design

The buffer repeater has a single portIn port of type Fw.BufferSend and an array of portOut ports of the same type. Each port call received on portIn is repeated to each connected portOut port. These repetitions emit a copy of the Fw::Buffer data.

3.1 Ports

Svc::BufferRepeater has the following ports:

Kind	Name	Port Type	Usage
`sync input`	`portIn`	`Fw.BufferSend`	Port for receiving initial Fw::Buffer
`output`	`portOut`	`[BufferRepeaterOutputPorts] Fw.BufferSend`	Port array for repeating Fw::Buffers
`output`	`deallocate`	`Fw.BufferSend`	Deallocate the original buffer
`output`	`allocate`	`Fw.BufferGet`	Port for allocating new memory
`event`	`Log`	`Fw.Log`	Port for emitting events
`text event`	`LogText`	`Fw.LogText`	Port for emitting text events
`time get`	`Time`	`Fw.Time`	Port for getting the time

3.1.1 portIn handler

The portIn port handler receives an Fw::Buffer data type and a port number. For each connected portOut port it allocates new memory large enough to hold a copy of the Fw::Buffer data via the allocate port, copies the data to the new invocation, and sends it to the active portOut port. This continues until each portOut port has been tried and at the end it returns the original buffer via deallocate.

Should an allocation fail, portOut is not called and an event may be emitted (see below).

3.2 Events

Name	Description
AllocationSoftFailure	WARNING_HI indicating allocation failure when configured to WARNING_ON_OUT_OF_MEMORY
AllocationHardFailure	FATAL indicating allocation failure when configured to FATAL_ON_OUT_OF_MEMORY

4. Configuration

Buffer repeater maximum output ports are configured using AcConstants.fpp as shown below:

constant BufferRepeaterOutputPorts = 10

The component's response to allocation failures is configured with a call to the configure method during system initialization. Possible values include:

Setting	Description
NO_RESPONSE_ON_OUT_OF_MEMORY	The component drops the `portOut` call and otherwise takes no response action
WARNING_ON_OUT_OF_MEMORY	The component drops the `portOut` call and emits a WARNING_HI event
FATAL_ON_OUT_OF_MEMORY	The component drops the `portOut` call and emits a FATAL event

{c++}

bufferRepeater.configure(Svc::BufferRepeater::FATAL_ON_OUT_OF_MEMORY);