cosmos::IOVector< MEMORY_REGION > Class Template Reference

A sequence of IOMemoryRegion specifications for scatter/gather I/O in the StreamIO API. More...

#include <iovector.hxx>

Inheritance diagram for cosmos::IOVector< MEMORY_REGION >:

Public Member Functions
size_t	leftBytes () const
	Returns the accumulated number of unprocessed bytes over the complete vector.

Protected Member Functions
auto	raw ()
bool	update (size_t processed_bytes)
	Update the vector given the number of bytes processed by a system call.

Friends
class	StreamIO
class	SendMessageHeader
class	ReceiveMessageHeader
template<typename MSGHDR >
class	MessageHeaderBase

Detailed Description

template<typename MEMORY_REGION>
class cosmos::IOVector< MEMORY_REGION >

A sequence of IOMemoryRegion specifications for scatter/gather I/O in the StreamIO API.

Definition at line 147 of file iovector.hxx.

Member Function Documentation

leftBytes()

template<typename MEMORY_REGION >

size_t cosmos::IOVector< MEMORY_REGION >::leftBytes ( ) const

inline

Returns the accumulated number of unprocessed bytes over the complete vector.

Definition at line 159 of file iovector.hxx.

                                 {
                size_t ret = 0;
                for (const auto &entry: *this) {
                        ret += entry.getLength();
                }
 
                return ret;
        }

raw()

template<typename MEMORY_REGION >

auto cosmos::IOVector< MEMORY_REGION >::raw ( )

inlineprotected

Definition at line 170 of file iovector.hxx.

{ return this->data()->asIovec(); };

update()

template<typename MEMORY_REGION >

bool cosmos::IOVector< MEMORY_REGION >::update ( size_t processed_bytes )

protected

Update the vector given the number of bytes processed by a system call.

Definition at line 11 of file iovector.cxx.

                                                           {
        // there's two approaches to update an io vector after partial
        // read/write operations:
        // a) removing completely processed entry from the begin of the
        //    vector and update partially processed ones
        // b) only updating pointer and length information but keeping
        //    the entry in the vector.
        // For b) the erase operation on the front of the vector is
        // somewhat expensive. For a) the re-entry into the kernel is
        // somewhat expensive, since the first entries processed will
        // potentially be finished already. For b) the advantage is that even
        // a fixed size std::array would be possible to use.  Currently we
        // follow b).
        bool vec_finished = true;
 
        for (auto &entry: *this) {
                processed_bytes -= entry.update(processed_bytes);
 
                if (!entry.finished()) {
                        vec_finished = false;
                        break;
                }
        }
 
        if (processed_bytes != 0) {
                cosmos_throw (RuntimeError("inconsistency while updating IOVector"));
        }
 
        return vec_finished;
}

Friends And Related Symbol Documentation

MessageHeaderBase

template<typename MEMORY_REGION >

template<typename MSGHDR >

friend class MessageHeaderBase

friend

Definition at line 154 of file iovector.hxx.

ReceiveMessageHeader

template<typename MEMORY_REGION >

friend class ReceiveMessageHeader

friend

Definition at line 152 of file iovector.hxx.

SendMessageHeader

template<typename MEMORY_REGION >

friend class SendMessageHeader

friend

Definition at line 151 of file iovector.hxx.

StreamIO

template<typename MEMORY_REGION >

friend class StreamIO

friend

Definition at line 150 of file iovector.hxx.

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

• include/io/iovector.hxx
• src/io/iovector.cxx