Driver::NV::Api Class Reference

This class defines the interface for a platform independent Non-volatile storage driver. More...

Detailed Description

This class defines the interface for a platform independent Non-volatile storage driver.

Only basic read/write operations are defined. How the NV storage is used is left the application and/or upper layers

The Interface assumes a paradigm of the NV storage is broken up into N pages where each page contains M bytes.

The interface itself is NOT thread safe. It is the responsibility of the users/clients of the driver to handle any threading issues.

#include <Api.h>

Inheritance diagram for Driver::NV::Api:

Public Member Functions
virtual bool	start () noexcept=0
	This method is used initialize/start the driver.
virtual void	stop () noexcept=0
	This method is used to stop/shutdown the driver.
virtual bool	write (size_t dstOffset, const void *srcData, size_t numBytesToWrite) noexcept=0
	This method writes N bytes from 'srcData' starting at the storage offset of 'dstOffset'.
virtual bool	read (size_t srcOffset, void *dstData, size_t numBytesToRead) noexcept=0
	This method reads N bytes starting at the storage offset of 'srcOffset' and stores the bytes into 'dstData'.
virtual size_t	getNumPages () const noexcept=0
	This method returns the total number of NV storage pages.
virtual size_t	getPageSize () const noexcept=0
	This method returns the NV storage page size.
virtual size_t	getTotalSize () const noexcept
	The method that returns the total storage size in bytes.
virtual	~Api ()
	Virtual destructor.

Constructor & Destructor Documentation

~Api()

virtual Driver::NV::Api::~Api ( )

inlinevirtual

Virtual destructor.

Member Function Documentation

getNumPages()

virtual size_t Driver::NV::Api::getNumPages ( ) const

pure virtualnoexcept

This method returns the total number of NV storage pages.

A Page is defined as the boundary/maximum amount of data that can be written in a single physical update of the NV storage

NOTE: ALWAYS use the getTotalSize() method for querying/determining the total available storage size.

Implemented in Driver::NV::File::Cpl::Api, Driver::NV::Gang, Driver::NV::Null, and Driver::NV::Onsemi::CAT24C512::Api.

getPageSize()

virtual size_t Driver::NV::Api::getPageSize ( ) const

pure virtualnoexcept

This method returns the NV storage page size.

See getNumPages() for more details about the definition of a page.

NOTE: ALWAYS use the getTotalSize() method for querying/determining the total available storage size.

Implemented in Driver::NV::File::Cpl::Api, Driver::NV::Gang, Driver::NV::Null, and Driver::NV::Onsemi::CAT24C512::Api.

getTotalSize()

virtual size_t Driver::NV::Api::getTotalSize ( ) const

inlinevirtualnoexcept

The method that returns the total storage size in bytes.

Note: This is canonical source of truth for the total available storage, i.e, if the driver instance is a 'Gang' driver instance then the method CAN return a different result from: getNumPages() * getPageSize()

Reimplemented in Driver::NV::Gang.

read()

virtual bool Driver::NV::Api::read ( size_t  srcOffset, void *  dstData, size_t  numBytesToRead  )

pure virtualnoexcept

This method reads N bytes starting at the storage offset of 'srcOffset' and stores the bytes into 'dstData'.

The application is responsible for ensuring that the size 'dstData' is at least 'numBytesToRead' in length.

The method returns true if operation was successful; else false is returned.

Implemented in Driver::NV::File::Cpl::Api, Driver::NV::Gang, Driver::NV::Null, and Driver::NV::Onsemi::CAT24C512::Api.

start()

virtual bool Driver::NV::Api::start ( )

pure virtualnoexcept

This method is used initialize/start the driver.

To 'restart' the driver, the application must call stop(), then start().

The method returns true if successful; else false is returned when an error occurred. If false is returned, future read/write calls will always return false.

Implemented in Driver::NV::File::Cpl::Api, Driver::NV::Gang, Driver::NV::Null, and Driver::NV::Onsemi::CAT24C512::Api.

stop()

virtual void Driver::NV::Api::stop ( )

pure virtualnoexcept

This method is used to stop/shutdown the driver.

Implemented in Driver::NV::File::Cpl::Api, Driver::NV::Gang, Driver::NV::Null, and Driver::NV::Onsemi::CAT24C512::Api.

write()

virtual bool Driver::NV::Api::write ( size_t  dstOffset, const void *  srcData, size_t  numBytesToWrite  )

pure virtualnoexcept

This method writes N bytes from 'srcData' starting at the storage offset of 'dstOffset'.

The application is responsible for ensuring that the size 'srcData' is at least 'numBytesToWrite' in length.

This write() method itself is synchronous, but the physically writing of the data to the NV storage is not guaranteed to synchronous, i.e. the physical write operation can completed AFTER the write() method returns. If a second write() call is made and the physical storage is still being updated from the first write() call, the second call will wait until the first physical write operation completes. There is no defined semantics for the waiting (i.e. it could be a blocking wait or a busy wait)

The method returns true if operation was successful; else false is returned.

Implemented in Driver::NV::File::Cpl::Api, Driver::NV::Gang, Driver::NV::Null, and Driver::NV::Onsemi::CAT24C512::Api.

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The documentation for this class was generated from the following file:

• Driver/NV/Api.h