select 函数实现 三种拓扑结构 n个客户端的异步通信 （完全图+线性链表+无环图）

http://blog.csdn.net/u011239443/article/details/51655257

一、这里只介绍简单的三个客户端异步通信（完全图拓扑结构）

1 1 //建立管道2 2 mkfifo 12 13 21 23 31 32

open顺序：cl1 读 ， cl2 cl3 向 cl1写cl2 读 ， cl1 cl3 向 cl2写cl3 读 ， cl1 cl2 向 cl3写顺序的规律就是 第i个 客户端读 其他各个客户端 ，其他的各个客户端 向 i 写 ，i 从 1 到 3.cl1 代码：

 1 #include<stdio.h>2 #include<stdlib.h>3 #include<string.h>4 #include<unistd.h>5 #include<sys/stat.h>6 #include<sys/types.h>7 #include<fcntl.h>8  #include <sys/time.h>9 #include<sys/select.h>10  #include <sys/select.h>1112        /* According to earlier standards */13        #include <sys/time.h>14        #include <sys/types.h>15        #include <unistd.h>1617 int main(int argc, char* argv[])//2118 {1920     int fd21, fd31,fd12,fd13 ;21     fd21 = open("21", O_RDONLY);22     fd31 = open("31", O_RDONLY);2324     fd12 = open("12",O_WRONLY);2526     fd13 = open("13",O_WRONLY);27     printf("OK!\n");282930     printf("OK!\n");31     fd_set read_sets ;32     fd_set write_sets ;33     int iret,iwrt ;34     char buf[1024] ;35     struct timeval tm ;36     while(1)37     {3839         tm.tv_sec = 1 ;40         tm.tv_usec = 0 ;41         FD_ZERO(&read_sets);42         FD_ZERO(&write_sets);4344         FD_SET(fd21, &read_sets);45         FD_SET(fd31, &read_sets);46         FD_SET( 0, &write_sets);47         //FD_SET(fd12, &write_sets);48         //FD_SET(fd13, &write_sets);4950         iret = select(10, &read_sets, NULL, NULL, &tm);51         iwrt = select(10,&write_sets,NULL,NULL,&tm);5253         //读54         if(iret != 0)55         {56             printf("active: %d\n", iret);5758             if(FD_ISSET(fd21, &read_sets))59             {60                 memset(buf, 0, 1024);61                 read(fd21, buf, 1023);62                 printf("from 2: %s\n", buf);63             }64             if(FD_ISSET(fd31, &read_sets))65             {66                 memset(buf, 0, 1024);67                 read(fd31, buf, 1023);68                 printf("from 3: %s\n", buf);69             }70         }717273         // write74         if(iwrt != 0)75         {76             printf("active: %d\n", iwrt);77             if(FD_ISSET( 0 /*fd12*/, &write_sets))78             {79                 memset(buf, 0, 128);80                 read(0, buf, 127) ;81                 write(fd12, buf, strlen(buf));82                 write(fd13, buf, strlen(buf));83             }84             /*if(FD_ISSET(fd13, &write_sets))85             {86                 memset(buf, 0, 128);87                 read(0, buf, 127) ;88                 write(fd13, buf, strlen(buf));89             }*/90         }9192     }93     return 0 ;94 }

cl2 代码：

 1 #include<stdio.h>2 #include<stdlib.h>3 #include<string.h>4 #include<unistd.h>5 #include<sys/stat.h>6 #include<sys/types.h>7 #include<fcntl.h>8 #include<sys/select.h>9 int main(int argc, char* argv[])//2110 {11     int fd12, fd32,fd21,fd23 ;12     fd21 = open("21",O_WRONLY);1314     fd12 = open("12", O_RDONLY);15     fd32 = open("32", O_RDONLY);1617     fd23 = open("23",O_WRONLY);181920     fd_set read_sets ,write_sets ;21     int iret ,iwrt;22     char buf[1024] ;23     struct timeval tm ;24     while(1)25     {2627         tm.tv_sec = 1 ;28         tm.tv_usec = 0 ;29         FD_ZERO(&read_sets);30         FD_ZERO(&write_sets);31         FD_SET(fd12, &read_sets);32         FD_SET(fd32, &read_sets);33         FD_SET( 0, &write_sets);34         //FD_SET(fd21,&write_sets);35         //FD_SET(fd23,&write_sets);3637         iret = select(10, &read_sets, NULL, NULL, &tm);38             iwrt = select(10,&write_sets,NULL,NULL,&tm);3940         if(iret != 0)41         {42             printf("active: %d\n", iret);4344             if(FD_ISSET(fd12, &read_sets))45             {46                 memset(buf, 0, 1024);47                 read(fd12, buf, 1023);48                 printf("from 1: %s\n", buf);49             }50             if(FD_ISSET(fd32, &read_sets))51             {52                 memset(buf, 0, 1024);53                 read(fd32, buf, 1023);54                 printf("from 3: %s\n", buf);55             }56         }575859         // write60         if(iwrt != 0)61         {62             printf("active: %d\n", iwrt);63             if(FD_ISSET( 0 , &write_sets))64             {65                 memset(buf, 0, 128);66                 read(0, buf, 127) ;67                 write(fd21, buf, strlen(buf));68                 write(fd23, buf, strlen(buf));69             }70         /*    if(FD_ISSET(fd23, &write_sets))71             {72                 memset(buf, 0, 128);73                 read(0, buf, 127) ;74                 write(fd23, buf, strlen(buf));75             }*/76         }7778     }79     return 0 ;80 }

cl3 代码：

 1 #include<stdio.h>2 #include<stdlib.h>3 #include<string.h>4 #include<unistd.h>5 #include<sys/stat.h>6 #include<sys/types.h>7 #include<fcntl.h>8 #include<sys/select.h>9 int main(int argc, char* argv[])//3110 {11     int fd13, fd23,fd31,fd32 ;12     fd31 = open("31",O_WRONLY);1314     fd32 = open("32",O_WRONLY);1516     fd13 = open("13", O_RDONLY);17     fd23 = open("23", O_RDONLY);1819     printf("OK!\n");20     fd_set read_sets ,write_sets ;21     int iret,iwrt ;22     char buf[1024] ;23     struct timeval tm ;24     while(1)25     {2627         tm.tv_sec = 1 ;28         tm.tv_usec = 0 ;29         FD_ZERO(&read_sets);30         FD_ZERO(&write_sets);31         FD_SET(fd13, &read_sets);32         FD_SET(fd23, &read_sets);33         //FD_SET(fd31,&write_sets);34         //FD_SET(fd32,&write_sets);35         FD_SET( 0, &write_sets);3637         iret = select(10, &read_sets, NULL, NULL, &tm);38         iwrt = select(10,&write_sets,NULL,NULL,&tm);3940         //读41     if(iret != 0)42         {43             printf("active: %d\n", iret);4445             if(FD_ISSET(fd13, &read_sets))46             {47                 memset(buf, 0, 1024);48                 read(fd13, buf, 1023);49                 printf("from 1: %s\n", buf);50             }51             if(FD_ISSET(fd23, &read_sets))52             {53                 memset(buf, 0, 1024);54                 read(fd23, buf, 1023);55                 printf("from 2: %s\n", buf);56             }57         }585960         // write61         if(iwrt != 0)62         {63             printf("active: %d\n", iwrt);64             if(FD_ISSET( 0 , &write_sets))65             {66                 memset(buf, 0, 128);67                 read(0, buf, 127) ;68                 write(fd31, buf, strlen(buf));69                  write(fd32, buf, strlen(buf));70             }71             /*if(FD_ISSET(fd32, &write_sets))72             {73                 memset(buf, 0, 128);74                 read(0, buf, 127) ;75                 write(fd32, buf, strlen(buf));76             }*/77         }78     }7980     return 0 ;81 }

二 、n个客户端异步通信 （线性链表的拓扑结构）

很显然的，如果用上述的方法需要每个客户端和其他客户端都直接相邻，即完全图。建立n个客户端通信，需要 2*(（n-1）+（n-2）+（n-3）+……3+2+1) = 2*（n-1 + 1）*(n -1)/2 =n * (n-1) 根管道，这么多的管道连接会使得代码实现变得非常冗杂、而且系统浪费资源管道。这里，用线性链表的拓扑结构，可以解决这个问题：1、 客户端以线性存储2、 当 pre 发来数据时， 打印出来，并且转发给next（若next存在）。3、 当 next 发来数据时， 打印出来，并且转发给pre（若pre存在）。4、 当键盘发来数据时，转发给next（若next存在），转发给pre（若pre存在）。例子：

1、客户端拓扑结构为 1——3——2——4

在文件存储如下：

2、我还编写一个读取topo.txt 文件 ，自动生成管道的代码：

BuildFIFO.cpp 如下：

 1 #include<stdio.h>2 #include<stdlib.h>3 #include<string.h>4 #include<string>5 #include<unistd.h>6 #include<sys/stat.h>7 #include<sys/types.h>8 #include<fcntl.h>9 #include <sys/time.h>10 #include<sys/select.h>11 using namespace std;12 int main(int argc, char* argv[])//2113 {1415     FILE* topu = fopen("topo.txt","r");16     int fir = 1;17     char dir[5],DIR[11];18     string str1,str2,str ;19     while(!feof(topu))20     {21         fscanf(topu ,"%s\n",dir);22         str1 = dir;23         if(fir)24         {25             fir =0 ;26             str2=str1;27             continue;28         }29         str=str1+"T"+str2;30         strcpy(DIR,str.c_str());31         mkfifo(DIR,0777);3233         str=str2+"T"+str1;34         strcpy(DIR,str.c_str());35         mkfifo(DIR,0777);36         str2 = str1;37     }3839     fclose(topu);4041     return 0;42 }

3、从客户端3键盘输入数据后，发送到各个客户端：

4、这里也有个 open 的 顺序的问题，但其实这种拓扑结构很好解决这个问题：

只需要每个相邻的客户端 读写顺序相反就能解决了如下：

 1 if(count & 1== 1) //判断节点的位置是奇数 还是 偶数 ，如果是 奇数 就 先读后写2     {3         if(strcmp("-1",pre->val)!=0)4         {56             fdReadFromPre = My_Open(pre->val,p->val,0);7             fdWriteToPre = My_Open(p->val,pre->val,1);8         }910         if(p->next!=NULL)11         {12             fdReadFromNext = My_Open(p->next->val,p->val,0);13             fdWriteToNext = My_Open(p->val,p->next->val,1);14         }15     }16     else                         //如果是偶数，先写后读17     {18         if(strcmp("-1",pre->val)!=0)19         {20             fdWriteToPre = My_Open(p->val,pre->val,1);21             fdReadFromPre = My_Open(pre->val,p->val,0);22         }2324         if(p->next!=NULL)25         {26             fdWriteToNext = My_Open(p->val,p->next->val,1);27             fdReadFromNext = My_Open(p->next->val,p->val,0);28         }2930     }

5、各客户端代码：

这里只发 cl1.cpp（其他客户端就是

1  while( strcmp("1",p->val)!=0)

1  char tembuf[1024] = "Form1 :";

这两句代码不一样而已）如下:

  1 #include<stdio.h>2 #include<stdlib.h>3 #include<string.h>4 #include<unistd.h>5 #include<sys/stat.h>6 #include<sys/types.h>7 #include<fcntl.h>8  #include <sys/time.h>9 #include<sys/select.h>101112 #define fdNULL -99991314 struct node15 {16     char val[5];17     node* next;18 };1920 int My_Open(char A[],char B[],int type)21 {22     char Cstr[11];23     memset( Cstr, '\0', sizeof(Cstr) );24     strcat(Cstr,A);25     strcat(Cstr,"T");26     strcat(Cstr,B);27     if(type == 0) return open(Cstr, O_RDONLY);28     else return open(Cstr, O_WRONLY);29 }303132 int main(int argc, char* argv[])//2133 {3435     FILE* topu = fopen("/home/soso/Desktop/1-30/LineSelect/topo.txt","r");36     char a[5];3738     node* L = (node*)calloc(1, sizeof(node)); //save topo39     strcpy(L->val,"-1");40     L->next = NULL;41     node* tem , *p ,*pre;42     p=L;43     while(!feof(topu))44     {45         fscanf(topu ,"%s\n",a);46         tem=  (node*)calloc(1, sizeof(node));47         strcpy(tem->val,a);48         tem->next = NULL;49         p->next=tem;50         p=p->next;51     }52     fclose(topu);5354     pre=L;55     p= L->next;56     int count = 1;57     while( strcmp("1",p->val)!=0)58     {59         p=p->next;60         pre=pre->next;61         ++count;62     }6364     int fdReadFromPre,fdReadFromNext,fdWriteToPre,fdWriteToNext ;65     fdReadFromPre=fdReadFromNext=fdWriteToPre=fdWriteToNext=fdNULL;66     if(count & 1== 1) //判断节点的位置是奇数 还是 偶数 ，如果是 奇数 就 先读后写67     {68         if(strcmp("-1",pre->val)!=0)69         {7071             fdReadFromPre = My_Open(pre->val,p->val,0);72             fdWriteToPre = My_Open(p->val,pre->val,1);73         }7475         if(p->next!=NULL)76         {77             fdReadFromNext = My_Open(p->next->val,p->val,0);78             fdWriteToNext = My_Open(p->val,p->next->val,1);79         }80     }81     else                         //如果是偶数，先写后读82     {83         if(strcmp("-1",pre->val)!=0)84         {85             fdWriteToPre = My_Open(p->val,pre->val,1);86             fdReadFromPre = My_Open(pre->val,p->val,0);87         }8889         if(p->next!=NULL)90         {91             fdWriteToNext = My_Open(p->val,p->next->val,1);92             fdReadFromNext = My_Open(p->next->val,p->val,0);93         }9495     }9697     printf("OK!\n");9899     fd_set read_sets ;100     fd_set write_sets ;101     int iret,iwrt ;102     char buf[1024] ;103     struct timeval tm ;104     while(1)105     {106107         tm.tv_sec = 1 ;108         tm.tv_usec = 0 ;109         FD_ZERO(&read_sets);110         FD_ZERO(&write_sets);111         if(fdReadFromPre != fdNULL)112             FD_SET(fdReadFromPre, &read_sets);113         if(fdReadFromNext != fdNULL)114             FD_SET(fdReadFromNext, &read_sets);115         FD_SET( 0, &write_sets);116117118         iret = select(10, &read_sets, NULL, NULL, &tm);119         iwrt = select(10,&write_sets,NULL,NULL,&tm);120121         //读122         if(iret != 0)123         {124125             if(FD_ISSET(fdReadFromPre, &read_sets))126             {127                 memset(buf, 0, 1024);128                 read(fdReadFromPre, buf, 1023);129                 if(fdWriteToNext!=fdNULL)             //把从pre读过来的数据转发到next去130                 write(fdWriteToNext, buf, strlen(buf));131                 printf("%s\n" ,buf);132             }133             if(FD_ISSET(fdReadFromNext, &read_sets))134             {135                 memset(buf, 0, 1024);136                 read(fdReadFromNext, buf, 1023);137                 if(fdWriteToPre!=fdNULL)             //把从next读过来的数据转发到pre去138                 write(fdWriteToPre, buf, strlen(buf));139                 printf("%s\n", buf);140             }141         }142143144         // write145         if(iwrt != 0)146         {147148             if(FD_ISSET( 0 , &write_sets))149             {150                 memset(buf, 0, 128);151                 read(0, buf, 127) ;152                 char tembuf[1024] = "Form1 :";153                 strcat(tembuf,buf);154                 if(fdWriteToNext!=fdNULL)               //把从键盘输入的数据向next、pre 转发155                 write(fdWriteToNext, tembuf, strlen(tembuf));156                 if(fdWriteToPre!=fdNULL)157                 write(fdWriteToPre, tembuf, strlen(tembuf));158             }159         }160161     }162     return 0;163 }

6、添加的客户端

1、在topo.txt 添加 客户名 再 换行2、再按一下 已经生成的 BuildFIFO 可执行文件，及自动生成所需的管道3、vim 出客户端，代码只需 改动两处（见5） 便可以完成客户端的添加。

三 、n个客户端异步通信 （无环图的拓扑结构）

线性拓扑结构有个很大的缺陷如图：客户端1 发送消息，要经过 3、2 的转发才能到达 4。当客户端数量很大时，链表前部和后部之间的通信的延迟会很大。如果改进，用树形拓扑机构就会很大的缓解这个问题。

1、 《计算机网络》的OSPF路由算法里面提到的泛洪法+无环图拓扑结构

如图 为Zhu客户端键盘输入数据：

2、存储结构

在文件topo.txt 中以类似于邻接的方式存储：topo文件格式为：顶点 节点个数 节点1 节点2 ……如图：客户端读取文件后的邻接表存储代码：

 1 map<string,bool> visit;23 struct TreeLine4 {5     vector<string> TreeNode;6     int level;  //层号7 };8910 map<string,TreeLine> Tree;

 1     FILE* topu = fopen("topo.txt","r");2     int fir = 1;3     int i,j;4     char strtem[5],strtem2[5],tem,Lval[5];5     int num;6     while(!feof(topu))7     {8         fscanf(topu ,"%s %d",strtem,&num);9         if(fir)                               //记录第一个客户端的名称10         {11             fir = 0;12             strcpy(Lval,strtem);13         }141516         TreeLine TemLine;17         for(int i =0 ;i< num;i++)18         {19             fscanf(topu," %s",strtem2);20             TemLine.TreeNode.push_back(strtem2);21         }22         fgetc(topu);2324         Tree[strtem]=TemLine;25         visit[strtem] = false; //初始化访问位26     }27     fclose(topu);

3、DFS来标注奇偶层号，判断open顺序（只要奇偶层顺序相反）

 1 void DFS(string val,int level)2 {3     visit[val] = true ;4     Tree[val].level = level;5     //cout<<val<<":"<<level<<"  "<<Tree[val].TreeNode.size()<<endl;6     int i;7     for(i = 0;i<Tree[val].TreeNode.size();++i)8     {9         if(visit[Tree[val].TreeNode[i]] == false)10             DFS(Tree[val].TreeNode[i],level+1);11     }12 }

 1 int level = 1;2     DFS(Lval,level);34     vector<int> fdReadOpen,fdWriteOpen;567          string TemString;8         if(Tree[UserName].level & 1 == 1)                //判断层号 奇数先读后写9         {10             for(i= 0 ;i<Tree[UserName].TreeNode.size();++i)11             {12             TemString=Tree[UserName].TreeNode[i]+"TO"+UserName;13             fdReadOpen.push_back(open(TemString.c_str(), O_RDONLY));14             }1516             for(i= 0 ;i<Tree[UserName].TreeNode.size();++i)17             {18             TemString = UserName;19             TemString+="TO"+Tree[UserName].TreeNode[i];20             fdWriteOpen.push_back(open(TemString.c_str(),O_WRONLY));21             }2223         }24         else                                             //判断层号 偶数数先写后读25         {26             for(i= 0 ;i<Tree[UserName].TreeNode.size();++i)27             {28             TemString = UserName;29             TemString+="TO"+Tree[UserName].TreeNode[i];30             fdWriteOpen.push_back(open(TemString.c_str(),O_WRONLY));31             }3233             for(i= 0 ;i<Tree[UserName].TreeNode.size();++i)34             {35             TemString=Tree[UserName].TreeNode[i]+"TO"+UserName;36             fdReadOpen.push_back(open(TemString.c_str(), O_RDONLY));37             }38         }

3、各客户端代码：

这次用了宏定义，每个客户端只需修改:

1 #define UserName "Ye"

其他代码都相同。这里分析客户端 Ye 的代码：

  1 #include <vector>2 #include<map>3 #include<string>4 #include<iostream>5 #include<stdio.h>6 #include<stdlib.h>7 #include<string.h>8 #include<unistd.h>9 #include<sys/stat.h>10 #include<sys/types.h>11 #include<fcntl.h>12 #include <sys/time.h>13 #include<sys/select.h>14 using namespace std;1516 #define MaxSize 100001718 #define UserName "Ye"1920 map<string,bool> visit;2122 struct TreeLine23 {24     vector<string> TreeNode;25     int level;  //层号26 };272829 map<string,TreeLine> Tree;3031 void DFS(string val,int level)32 {33     visit[val] = true ;34     Tree[val].level = level;35     //cout<<val<<":"<<level<<"  "<<Tree[val].TreeNode.size()<<endl;36     int i;37     for(i = 0;i<Tree[val].TreeNode.size();++i)38     {39         if(visit[Tree[val].TreeNode[i]] == false)40             DFS(Tree[val].TreeNode[i],level+1);41     }42 }43444546 int main(int argc, char* argv[])47 {4849     FILE* topu = fopen("topo.txt","r");50     int fir = 1;51     int i,j;52     char strtem[5],strtem2[5],tem,Lval[5];53     int num;54     while(!feof(topu))55     {56         fscanf(topu ,"%s %d",strtem,&num);57         if(fir)                               //记录第一个客户端的名称58         {59             fir = 0;60             strcpy(Lval,strtem);61         }626364         TreeLine TemLine;65         for(int i =0 ;i< num;i++)66         {67             fscanf(topu," %s",strtem2);68             TemLine.TreeNode.push_back(strtem2);69         }70         fgetc(topu);7172         Tree[strtem]=TemLine;73         visit[strtem] = false; //初始化访问位74     }75     fclose(topu);7677     int level = 1;78     DFS(Lval,level);7980     vector<int> fdReadOpen,fdWriteOpen;818283     string TemString;84     if(Tree[UserName].level & 1 == 1)                //判断层号 奇数先读后写85     {86         for(i= 0 ;i<Tree[UserName].TreeNode.size();++i)87         {88             TemString=Tree[UserName].TreeNode[i]+"TO"+UserName;89             fdReadOpen.push_back(open(TemString.c_str(), O_RDONLY));90         }9192         for(i= 0 ;i<Tree[UserName].TreeNode.size();++i)93         {94             TemString = UserName;95             TemString+="TO"+Tree[UserName].TreeNode[i];96             fdWriteOpen.push_back(open(TemString.c_str(),O_WRONLY));97         }9899     }100     else                                             //判断层号 偶数数先写后读101     {102         for(i= 0 ;i<Tree[UserName].TreeNode.size();++i)103         {104             TemString = UserName;105             TemString+="TO"+Tree[UserName].TreeNode[i];106             fdWriteOpen.push_back(open(TemString.c_str(),O_WRONLY));107         }108109         for(i= 0 ;i<Tree[UserName].TreeNode.size();++i)110         {111             TemString=Tree[UserName].TreeNode[i]+"TO"+UserName;112             fdReadOpen.push_back(open(TemString.c_str(), O_RDONLY));113         }114     }115116117118119     printf("OK!\n");120121     fd_set read_sets ;122     fd_set write_sets ;123     int iret,iwrt ;124     char buf[1024] ;125     struct timeval tm ;126     while(1)127     {128129         tm.tv_sec = 1 ;130         tm.tv_usec = 0 ;131         FD_ZERO(&read_sets);132         FD_ZERO(&write_sets);133         for(i=0;i<fdReadOpen.size();i++)134             FD_SET(fdReadOpen[i], &read_sets);135         FD_SET( 0, &write_sets);136137         iret = select(1023, &read_sets, NULL, NULL, &tm);138         iwrt = select(1023,&write_sets,NULL,NULL,&tm);139140         //读141         if(iret != 0)142         {143144             for(i=0;i<fdReadOpen.size();i++)               //遍历ReadOpen145             {146                 if(FD_ISSET(fdReadOpen[i], &read_sets))  //当收到ReadOpen[i]时147                 {148                     memset(buf, 0, 1024);149                     read(fdReadOpen[i], buf, 1023);150                     printf("%s\n" ,buf);               //打印出来151                     for(j=0;j<fdWriteOpen.size();j++)   //向其他客户端转发152                     {153                         if(j != i)                                //AtoB 和 BtoA 的fdOpen存储位置是对应的154                             write(fdWriteOpen[j], buf, strlen(buf));155                     }156                 }157             }158         }159160161         // write162         if(iwrt != 0)163         {164             if(FD_ISSET( 0 , &write_sets))165             {166                 memset(buf, 0, 128);167                 read(0, buf, 127) ;168                 char tembuf[1024] = UserName;169                 strcat(tembuf," :");170                 strcat(tembuf,buf);171                 for(i =0 ;i< fdWriteOpen.size();i++)172                     write(fdWriteOpen[i], tembuf, strlen(tembuf));173             }174         }175176     }177178179     return 0;180 }

4、添加的客户端

1、按照输入格式在topo.txt 添加2、再按一下 已经生成的 BuildFIFO 可执行文件，及自动生成所需的管道3、vim 出客户端，代码只需 改动一处（见3） 便可以完成客户端的添加。