学步园

搞通信的经常需要画消息序列图（Message Sequence Chart, MSC）。Windows下的Visio和Linux下的Dia能够画很好的MSC。但有时为了方便想画纯字符的MSC。我曾经用Python写过一个简单的工具来帮助实现这样的功能，工具的名字叫seqChart。

下图就是seqChart画的图（请用等宽字符字体察看，Monospaced
Font）。                     

<br /> |-----| |---|<br /> |ALICE| |BOB|<br /> |-----| |---|<br /> | |<br /> -----INVITE----><br /> | |<br /> | |<br /> | |<br /> <-----100-------<br /> | |<br /> | |<br /> | |<br /> <-----180-------<br /> | |<br /> | |<br /> | |<br /> <-----200-------<br /> | |<br /> | |<br /> | |<br /> ------ACK------><br /> | |<br /> | |<br /> | |<br /> (~~~~~~~~~~~) (~~~~~~~~~~~)<br /> (MID_SESSION) (MID_SESSION)<br /> (~~~~~~~~~~~) (~~~~~~~~~~~)<br /> | |<br /> <-----BYE-------<br /> | |<br /> | |<br /> | |<br /> ------200------><br /> | |<br /> | |<br /> | |<br /> | |<br /> v v </p> <p>              

下面就是生成此图用到的命令

SND ALICE BOB INVITE<br /> RCV ALICE BOB 100<br /> SND BOB ALICE 180<br /> SND BOB ALICE 200<br /> SND ALICE BOB ACK<br /> STATE ALICE MID_SESSION<br /> STATE BOB MID_SESSION<br /> RCV ALICE BOB BYE<br /> SND ALICE BOB 200                          

把命令序列保存为文件，然后执行下面的命令，即可生成图到文件中。

seqChart.py seqChart.input > seqChart.output

seqChart共有4条命令SND，RCV，STATE，LST，其中RCV和SND只是参数的顺序不同，可互换。发送接收消息的实体定义为Process，Process的数量可以是无限多。Process在图上出现的顺序即命令出现的顺序。命令的参数个数是固定的必备的。SND，RCV和STATE都是自解释的。LST不参与画图，只用来察看当前的命令序列产生的中间状态。

这4条命令的格式为

SND from-process to-process message

RCV dest-process from-process message

STATE process a-state

LST

为追求简单，seqChart没有考虑异常处理。

附代码：

#<br /> #designed by blog.csdn.net/xuhx www.lingcloud.com www.feexing.com<br /> #<br /> import fileinput<br /> import array</p> <p>gProcesses=[]<br /> gMsgSequence=[]<br /> MESSAGE='MSG'<br /> STATE='STA'<br /> COMMENT='#'</p> <p>def snd(process,toProcess,message):<br /> global gProcesses<br /> global gMsgSequence<br /> if process not in gProcesses:<br /> gProcesses.append(process)<br /> if toProcess not in gProcesses:<br /> gProcesses.append(toProcess)<br /> gMsgSequence.append((MESSAGE,(process,toProcess,message)))</p> <p>def rcv(process,fromProcess,message):<br /> snd(fromProcess,process,message)</p> <p>def state(process,astate):<br /> if process not in gProcesses:<br /> gProcesses.append(process)<br /> gMsgSequence.append((STATE,(process,astate)))</p> <p>def lst():<br /> print 'processes:'<br /> print gProcesses<br /> print<br /> print 'chart:'<br /> for type,content in gMsgSequence:<br /> print type,content </p> <p>def parseCmd(cmd):<br /> cmd=cmd.strip()<br /> if len(cmd)==0:<br /> return True<br /> if cmd.startswith(COMMENT):<br /> return True<br /> cmds=cmd.split()</p> <p> theFunction=cmds[0].lower()<br /> theArgs=cmds[1:]<br /> if theFunction=='snd':<br /> snd(*theArgs)<br /> elif theFunction=='rcv':<br /> rcv(*theArgs)<br /> elif theFunction=='state':<br /> state(*theArgs)<br /> elif theFunction=='lst':<br /> lst(*theArgs)<br /> else:<br /> raise 'cmd wrong'<br /> return False<br /> return True</p> <p>def main():<br /> global gProcesses<br /> global gMsgSequence<br /> for line in fileinput.input():<br /> parseCmd(line)<br /> canvas=ChartCanvas(gProcesses,gMsgSequence)<br /> canvas.draw()<br /> canvas.output()</p> <p>class Canvas:<br /> BLANK=' '<br /> HLINE='-'<br /> VLINE='|'<br /> HLARROW='<'<br /> HRARROW='>'<br /> VUARROW='^'<br /> VDARROW='v'<br /> INTERSECT='+'<br /> XINTERSECT='*'<br /> WAVEVLLINE='('<br /> WAVEVRLINE=')'<br /> WAVEHLINE='~'</p> <p> def __init__(self,col,row):<br /> self.row=row<br /> self.column=col<br /> self.canvas=array.array('c',[self.BLANK]*(row*col))</p> <p> def __draw(self,col,row,char):<br /> self.canvas[self.column*row+col]=char</p> <p> def reset(self):<br /> for i in range(self.column*self.row):<br /> self.canvas[i]=self.BLANK</p> <p> def output(self):<br /> for i in range(self.row):<br /> lineStart=self.column*i<br /> line=self.canvas[lineStart:lineStart+self.column].tostring()<br /> print line</p> <p> def point(self,col,row,char):<br /> self.__draw(col,row,char)</p> <p> def hline(self,col,row,length,direction=None,arrow=None,hChar=HLINE):<br /> start=col<br /> stop=col+length<br /> if direction:<br /> start=col-length+1<br /> stop=col+1</p> <p> for i in range(start,stop):<br /> self.point(i,row,hChar)</p> <p> if arrow:<br /> if direction:<br /> self.point(start,row,self.HLARROW)<br /> else:<br /> self.point(stop-1,row,self.HRARROW)</p> <p> def vline(self,col,row,length,direction=None,arrow=None,vChar=VLINE):<br /> start=row<br /> stop=row+length<br /> if direction:<br /> start=row-length+1<br /> stop=row+1<br /> for i in range(start,stop):<br /> self.point(col,i,vChar)</p> <p> if arrow:<br /> if direction:<br /> self.point(col,start,Canvas.VUARROW)<br /> else:<br /> self.point(col,stop-1,Canvas.VDARROW)</p> <p> def rect(self,col,row,width,height):<br /> self.vline(col,row,height)<br /> self.vline(col+width-1,row,height)<br /> self.hline(col+1,row+height-1,width-2)<br /> self.hline(col+1,row,width-2)</p> <p> def waveRect(self,col,row,width,height):<br /> self.vline(col,row,height,vChar=self.WAVEVLLINE)<br /> self.vline(col+width-1,row,height,vChar=self.WAVEVRLINE)<br /> self.hline(col+1,row+height-1,width-2,hChar=self.WAVEHLINE)<br /> self.hline(col+1,row,width-2,hChar=self.WAVEHLINE)</p> <p> def text(self,col,row,astr,center=None):<br /> left=col<br /> if center:<br /> left=col-len(astr)/2<br /> for i in range(len(astr)):<br /> self.point(left+i,row,astr[i])</p> <p> def __textRect(self,str,width=None):<br /> strlen=len(str)<br /> if not width :<br /> cols=strlen<br /> rows=1<br /> elif strlen<=width:<br /> cols=width<br /> rows=1<br /> else:<br /> cols=width<br /> rows=strlen/width<br /> remain=strlen % width<br /> if remain:<br /> rows +=1<br /> return (cols,rows)</p> <p> def rectText(self,col,row,astr,width=None,center=None):<br /> cols,rows=self.__textRect(astr,width)<br /> for i in range(rows):<br /> line=astr[cols*i:cols*i+cols]<br /> if center:<br /> self.text(col,row+1+i,line,center)</p> <p> left=col-cols/2-1<br /> top=row<br /> width=cols+2<br /> height=rows+2<br /> self.rect(left,top,width,height)<br /> else:<br /> self.text(col+1,row+1+i,line,center)</p> <p> left=col<br /> top=row<br /> width=cols+2<br /> height=rows+2<br /> self.rect(left,top,width,height)<br /> return (width,height)</p> <p> def waveRectText(self,col,row,astr,width=None,center=None):<br /> cols,rows=self.__textRect(astr,width)<br /> for i in range(rows):<br /> line=astr[cols*i:cols*i+cols]<br /> if center:<br /> self.text(col,row+1+i,line,center)</p> <p> left=col-cols/2-1<br /> top=row<br /> width=cols+2<br /> height=rows+2<br /> self.waveRect(left,top,width,height)<br /> else:<br /> self.text(col+1,row+1+i,line,center)</p> <p> left=col<br /> top=row<br /> width=cols+2<br /> height=rows+2<br /> self.waveRect(left,top,width,height)<br /> return (width,height)</p> <p>class ChartCanvas(Canvas):<br /> SPAN=4<br /> MARGIN=5<br /> ROWSPAN=4 </p> <p> def __init__(self,process,sequence):<br /> self.process=process<br /> self.sequence=sequence<br /> self.states=[]<br /> self.messages=[]<br /> self.processInfo={}</p> <p> for type,contents in self.sequence:<br /> if type==MESSAGE:<br /> if contents[2] not in self.messages:<br /> self.messages.append(contents[2])<br /> elif type==STATE:<br /> if contents[1] not in self.states:<br /> self.states.append(contents[1])<br /> else:<br /> raise 'type not supported'</p> <p> cols,rows=self.initCanvas()<br /> Canvas.__init__(self,cols,rows)</p> <p> def initCanvas(self):<br /> processCount=len(self.process)<br /> maxTextLen=max([len(l) for l in (self.states+self.messages)])<br /> self.interval=self.SPAN+maxTextLen<br /> #self.currow=self.MARGIN<br /> for i in range(len(self.process)):<br /> p=self.process[i]<br /> col=self.MARGIN+self.interval*(i+1)<br /> row=self.MARGIN<br /> currow=row<br /> self.processInfo[p]=(col,row,currow)<br /> #self.processInfo[p]=(col,row)</p> <p> cols=col+self.interval+self.MARGIN<br /> rows=(len(self.sequence)+5)*self.ROWSPAN+2*self.MARGIN<br /> return (cols,rows)</p> <p> def draw(self):<br /> self.drawHeader()<br /> self.drawSequence()</p> <p> def drawMsg(self,fp,tp,msg):<br /> fcol,frow,fcurrow=self.processInfo[fp]<br /> tcol,trow,tcurrow=self.processInfo[tp]<br /> top=max(fcurrow,tcurrow)<br /> left=min(fcol,tcol)<br /> right=max(fcol,tcol)<br /> if(fcol<tcol):<br /> self.hline(left,top,right-left+1,arrow=True)<br /> else:<br /> self.hline(right,top,right-left+1,direction=True,arrow=True) </p> <p> textLeft=left+((right-left+1)-len(msg))/2<br /> self.text(textLeft,top,msg)<br /> fcurrow=tcurrow=top+self.ROWSPAN<br /> self.processInfo[fp]=fcol,frow,fcurrow<br /> self.processInfo[tp]=tcol,trow,tcurrow</p> <p> for p in self.process:<br /> col,row,currow=self.processInfo[p]<br /> if currow<fcurrow:<br /> currow=fcurrow<br /> self.processInfo[p]=(col,row,currow)</p> <p> def drawState(self,p,s):<br /> col,row,currow=self.processInfo[p]<br /> width,height=self.waveRectText(col,currow,s,center=True)<br /> currow+=self.ROWSPAN<br /> self.processInfo[p]=(col,row,currow)</p> <p> def drawSequence(self):<br /> for type,contents in self.sequence:<br /> if type==MESSAGE:<br /> fromProcess=contents[0]<br /> toProcess=contents[1]<br /> message=contents[2]<br /> self.drawMsg(fromProcess,toProcess,message)<br /> elif type==STATE:<br /> process=contents[0]<br /> state=contents[1]<br /> self.drawState(process,state)<br /> else:<br /> raise 'type not supported'</p> <p> def drawHeader(self):<br /> for p in self.process:<br /> col,row,currow=self.processInfo[p]<br /> #col,row=self.processInfo[p]<br /> width,height=self.rectText(col,currow,p,center=True)<br /> bottom=row+height<br /> currow+=self.ROWSPAN<br /> self.processInfo[p]=(col,row,currow)<br /> #self.processInfo[p]=(col,row)<br /> self.vline(col,bottom,self.row-self.MARGIN-bottom,arrow=True)<br /> #self.currow+=self.ROWSPAN </p> <p>if '__main__'==__name__:<br /> main()<br /> pass