Allows iteration through the list of message headers received in the control parameter of the socket_sendto_control / socket_recvfrom_control methods. More...

#include <MsgHeader.h>

Public Member Functions
	MsgHeaderIterator (nsapi_msghdr_t *hdr, nsapi_size_t size)
	Create a MsgHeaderIterator over given nsapi_msghdr_t list. More...

bool	has_next ()
	Checks if the next address of the iterator is a valid list member. More...

nsapi_msghdr_t *	next ()
	Returns next element of the list. More...

Detailed Description

Allows iteration through the list of message headers received in the control parameter of the socket_sendto_control / socket_recvfrom_control methods.

Members types

MsgHeaderIterator works on the list which members are of type nsapi_msghdr_t or other types extending this struct. For example nsapi_pktinfo:

typedef struct nsapi_pktinfo {
    nsapi_msghdr_t hdr;
    nsapi_addr_t   ipi_addr;
    int            ipi_ifindex;
    void          *network_interface;
} nsapi_pktinfo_t;

There are two requirements for such structures to work well with MsgHeaderIterator.

First element needs to be of type nsapi_msghdr_t.
Value of the field len of the nsapi_msghdr_t needs to bet set to the size of the whole extending type. For example:

nsapi_pktinfo_t pkt_info;

pkt_info.hdr.len = sizeof(nsapi_pktinfo_t);

This value is used in the MsgHeaderIterator to calculate proper addresses of the list elements.

Example

Code presenting minimal usage example.

struct default_buffer_t {
    default_buffer_t()
    {
        el1.hdr.len = sizeof(nsapi_pktinfo_t);
        el2.len = sizeof(nsapi_msghdr_t);
        el3.len = sizeof(nsapi_msghdr_t);
        el4.hdr.len = sizeof(nsapi_pktinfo_t);
    }
    nsapi_pktinfo_t el1;
    nsapi_msghdr_t el2;
    nsapi_msghdr_t el3;
    nsapi_pktinfo_t el4;
};
default_buffer buff;
nsapi_msghdr_t *hdr_p = reinterpret_cast<nsapi_msghdr_t *>(&buff);
MsgHeaderIterator it(hdr_p, sizeof(buff));
it.has_next() // returns true
auto p1 = it.next()  // returns pointer to el1
auto p2 = it.next()  // returns pointer to el2
auto p3 = it.next()  // returns pointer to el3
auto p4 = it.next()  // returns pointer to el4
it.has_next() // returns false
 auto p5 = it.next() // returns nullptr

Note: More usage examples are implemented in the MsgHeaderIterator unit test in netsocket/tests/UNITTESTS/NetworkStack/test_MsgHeaderIterator.cpp

Definition at line 91 of file MsgHeader.h.

Constructor & Destructor Documentation

MsgHeaderIterator	(	nsapi_msghdr_t *	hdr,
		nsapi_size_t	size
	)

Create a MsgHeaderIterator over given nsapi_msghdr_t list.

Parameters

hdr	Pointer to the first list element.
size	Size of the whole list.

Definition at line 97 of file MsgHeader.h.

Member Function Documentation

bool has_next ( )

Checks if the next address of the iterator is a valid list member.

Return values

True	if the next address is a valid member.
False	otherwise.

Definition at line 108 of file MsgHeader.h.

nsapi_msghdr_t* next ( )

Returns next element of the list.

Return values

nullptr	if the list doesn't contain next element.
Pointer	to the next element otherwise.

Definition at line 134 of file MsgHeader.h.

Public Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation

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