cosmos::IOMemoryRegion< IOVEC > Struct Template Reference

I/O memory region specification used with scatter/gather I/O in StreamIO API. More...

#include <iovector.hxx>

Inheritance diagram for cosmos::IOMemoryRegion< IOVEC >:

Public Types
using	PtrType = decltype(IOVEC::iov_base)

Public Member Functions
auto	getBase ()
auto	getBase () const
void	setBase (PtrType base)
size_t	getLength () const
void	setLength (size_t length)
bool	finished () const
size_t	update (const size_t processed_bytes)
	Update the current memory region to accommodate the given number of processed bytes.

Friends
template<typename ENTRY_TYPE >
class	IOVector

Detailed Description

template<typename IOVEC>
struct cosmos::IOMemoryRegion< IOVEC >

I/O memory region specification used with scatter/gather I/O in StreamIO API.

This structure defines a single memory region to be used for vector read/write on file descriptors. It is used a base class for read/write specializations due to different constness requirements of the underlying data structure.

IOVEC is either the system defined struct iovec or our remodelled struct iovec_const.

Definition at line 49 of file iovector.hxx.

Member Typedef Documentation

PtrType

template<typename IOVEC >

using cosmos::IOMemoryRegion< IOVEC >::PtrType = decltype(IOVEC::iov_base)

Definition at line 57 of file iovector.hxx.

Member Function Documentation

finished()

template<typename IOVEC >

bool cosmos::IOMemoryRegion< IOVEC >::finished ( ) const

inline

Definition at line 67 of file iovector.hxx.

{ return getLength() == 0; }

getBase() [1/2]

template<typename IOVEC >

auto cosmos::IOMemoryRegion< IOVEC >::getBase ( )

inline

Definition at line 60 of file iovector.hxx.

{ return this->iov_base; }

getBase() [2/2]

template<typename IOVEC >

auto cosmos::IOMemoryRegion< IOVEC >::getBase ( ) const

inline

Definition at line 61 of file iovector.hxx.

{ return this->iov_base; }

getLength()

template<typename IOVEC >

size_t cosmos::IOMemoryRegion< IOVEC >::getLength ( ) const

inline

Definition at line 64 of file iovector.hxx.

{ return this->iov_len; }

setBase()

template<typename IOVEC >

void cosmos::IOMemoryRegion< IOVEC >::setBase ( PtrType base )

inline

Definition at line 62 of file iovector.hxx.

{        this->iov_base = base; }

setLength()

template<typename IOVEC >

void cosmos::IOMemoryRegion< IOVEC >::setLength ( size_t length )

inline

Definition at line 65 of file iovector.hxx.

{        this->iov_len = length; }

update()

template<typename IOVEC >

size_t cosmos::IOMemoryRegion< IOVEC >::update ( const size_t processed_bytes )

inline

Update the current memory region to accommodate the given number of processed bytes.

Once a system call processes part or all of an IOVector, use this function to adjust the remaining length and advance the base pointer.

This function returns the number of bytes that account to this IOVector entry. If more bytes have been processed than this entry holds then the next IOVector entry needs to be updated, too.

Definition at line 79 of file iovector.hxx.

                                                    {
                auto to_reduce = std::min(processed_bytes, getLength());
 
                if constexpr (std::is_same_v<IOVEC, struct iovec_const>) {
                        auto data = reinterpret_cast<const char*>(getBase());
                        setBase(reinterpret_cast<PtrType>(data + to_reduce));
                } else {
                        auto data = reinterpret_cast<char*>(getBase());
                        setBase(reinterpret_cast<PtrType>(data + to_reduce));
                }
 
                setLength(getLength() - to_reduce);
                return to_reduce;
        }

Friends And Related Symbol Documentation

IOVector

template<typename IOVEC >

template<typename ENTRY_TYPE >

friend class IOVector

friend

Definition at line 55 of file iovector.hxx.

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

• include/io/iovector.hxx