Groupsock (netaddress)--live555 source Read (iv) network

Groupsock (netaddress)--live555 source Read (iv) network

• Groupsock (netaddress)--live555 source Read (iv) network
  • Brief introduction
  • 1) netaddress Network address class Brief
  • Here is its definition
  • Assign method (allocated space)
  • The structure of netaddress
  • Clean method (cleanup) and destruction
  • Operate= Overloaded Assignment operation

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This article by Mob Lym fabricated, welcome reprintmy.oschina.net/oloroso

Brief introduction

A network connection that uses a socket, usually consisting of an address ( IP ) and a port ( port ).
Some data types are defined in live555, indicating the type of network address currently supported.

1 // Definition of a type representing a low-level network address. 2 // at present, which is the 32-bits, for IPV4.  Later, generalize it,3// to allow for IPv6. 4 // a representation of the underlying network address definition. Currently, it defaults to 32 bits, IPv4. In the future, IPV6 can be extended to support.  5typedef u_int32_t netaddressbits; 6 typedef u_int16_t Portnumbits;

defined in the filelive555sourcecontrol\groupsock\include\NetAddress.hh

1) netaddress Network address class Brief

NetAddressis a class that holds the network address, which is not the encapsulation of the pair struct sockaddr . It internally defines two data members, each of which is used to hold address data u_int8_t* fData and to indicate the length of the address unsigned fLength .

Here is its definition

1 classnetaddress {2      Public:3Netaddress (u_int8_tConst*data,4unsigned length =4 /*default:32 bits IPv4*/);5netaddress (Unsigned length =4);//sets address data to All-zeros6Netaddress (netaddressConst&orig);7netaddress&operator= (netaddressConst&rightside);8     Virtual~netaddress ();9 TenUnsigned length ()Const{returnflength;} Oneu_int8_tConst* Data ()Const //Always in network byte order A{returnFData;} -  -     Private: the     voidAssign (u_int8_tConst*data, unsigned length); -     voidClean (); -  - unsigned flength; +u_int8_t*FData; -};

definition of netaddress

Assign method (allocated space)

This is not a constructor, because this method is a key method. The constructor also uses it.
assignfDatadynamically allocates memory space and copies data to members. Parameters are length used to determine the size of the allocated space, and the parameters are data copied to the requested new space as a data source. It is important to note that the permissions of this method are private correct, so no check is data==NULL possible.
The interesting thing about C + + here is that it is new分配失败不是返回NULL 抛出异常(std::bad_alloc e) . Unless it is overloaded with new or uses no throw new (std::nothrow) . However, earlier implementations of the C + + compiler might be the same as new and the malloc behavior, all of which return null.

1 //request a length byte memory space for FDate and copy data to the new space2 voidNetaddress::assign (u_int8_tConst*data, unsigned length) {3FData =NewU_int8_t[length];4   if(FData = =NULL) {5Flength =0;6     return;7   }8 9    for(Unsigned i =0; i < length; ++i) Fdata[i] =Data[i];TenFlength =length; One}

The structure of netaddress

NetAddressThree constructors are defined, two common parameter constructs and one copy construction (copy construction is also a kind of parameter structure).
The consistent feature of the three constructors is that the fData memory space is applied dynamically for the member. The code is simple, not detailed.

1 //constructor to request a length byte memory space for fdate and to copy data to the new space2Netaddress::netaddress (u_int8_tConst*data, unsigned length) {3 assign (data, length);4 }5 //request a length byte memory space for FDate and clear the new space by 06 netaddress::netaddress (unsigned length) {7FData =NewU_int8_t[length];8   if(FData = =NULL) {9Flength =0;Ten     return; One   } A  -    for(Unsigned i =0; i < length; ++i) Fdata[i] =0; -Flength =length; the } -  - //Copy Construction -Netaddress::netaddress (netaddressConst&orig) { + Assign (Orig.data (), orig.length ()); -}

constructor FunctionClean method (cleanup) and destruction

cleanmethod is used to fData dispose of the memory space that is pointed to. is to NetAddress save the object 数据给清理掉 , note that this method is private permission.

Off-topic: clean and clear mean a little bit different.

1 // Clear Address Data 2 void Netaddress::clean () {3   Delete [] fData; FData = NULL; 4   0 ; 5 }

A destructor is a call to clean.

1 // Destruction 2 netaddress::~netaddress () {3clean  (); 4 }

Operate= Overloaded Assignment operation

This is very simple, not detailed.

1 //overloading = Assignment2netaddress& netaddress::operator= (netaddressConst&rightside) {3   if(&rightside! = This) {4 Clean ();5 Assign (Rightside.data (), rightside.length ());6   }7   return* This;8}

Groupsock (netaddress)--live555 source Read (iv) network