wordanalyse.java

操作系统中的语法分析,主要是判断语言是否合乎语言规范

import java.io.*;
class WordAnalyse
{
	int cc=0,ll,kk=0,sym=0,num=0,row=0,err=0;
	char ch;
	int wsym[]=new  int[15];
	int ssym[]=new  int[65536];
	String KeyWord[]=new String[15];
	char line[]=new char[81];
	int flag=0;
	StringBuffer strid=new StringBuffer();
	String inputstr=new String();
	InputStreamReader in;
	RandomAccessFile infile;
	OutputStreamWriter write;
	String str=new String();
    //内部码对照
        final static int PROGRAM=1;
		final static int CONST=2;
		final static int VAR=3;
		final static int INTEGER=4;
		final static int LONG=5;
		final static int PROCEDURE=6;
		final static int IF=7;
		final static int THEN=8;
		final static int WHILE=9;
		final static int DO=10;
		final static int READ=11;
		final static int WRITE=12;
		final static int BEGIN=13;
		final static int END=14;
		final static int ODD=15;
		final static int PLUS=16;
		final static int MINUS=17;
		final static int TIMES=18;
		final static int SLASH=19;
		final static int EQL=20;
		final static int NLEQ=21;
		final static int LSS=22;
		final static int LEQ=23;
		final static int GTR=24;
		final static int GEQ=25;
		final static int PERIOD=26;
		final static int COMMA=27;
		final static int SEMICOLON=28;
		final static int COLON=29;
		final static int BECOMES=30;
		final static int LPAREN=31;
		final static int RPAREN=32;
		final static int USNUMBER=33;
		final static int IDENT=34;
		final static int NEQ=35;
		//关键字的个数
        final static int NORW=15;
        //符号的最大长度
        final static int  AL=20;
        //number的最大位数
        final static int NMAX=14;
        
    //构造函数
    public WordAnalyse()
    {
         SetStringToInt();
         SetSym();
         SetKeyWord();
    }
        
	public void SetStringToInt()
	{
	wsym[0]=BEGIN;	
	wsym[1]=CONST;
	wsym[2]=DO;
	wsym[3]=END;
	wsym[4]=IF;
	wsym[5]=INTEGER;
	wsym[6]=LONG;
	wsym[7]=ODD;
	wsym[8]=PROCEDURE;
	wsym[9]=PROGRAM;
	wsym[10]=READ;
	wsym[11]=THEN;
	wsym[12]=VAR;
    wsym[13]=WHILE;
	wsym[14]=WRITE;
	}		
	//设置单字符符号
	public void	SetSym()
	{
	//初始化单符号数组
	//for(int i=0;i<=255;i++) ssym[i]=0;
	
	ssym['+']=PLUS;
	ssym['-']=MINUS;
	ssym['*']=TIMES;
	ssym['/']=SLASH;
	ssym['(']=LPAREN;
	ssym[')']=RPAREN;
	ssym['=']=EQL;
	ssym[',']=COMMA;
	ssym['.']=PERIOD;
	ssym['#']=NEQ;
	ssym[';']=SEMICOLON;
	}
	//设置要进行读的文件路径
	public boolean OpenFile(String path)
	{
		try
		{
			in=new InputStreamReader(new FileInputStream(path));
		}
		catch(FileNotFoundException e)
		{
		 e.printStackTrace();
		}
		catch(IOException e1)
		{
			e1.printStackTrace();
		}
		return true;
	}
	public int FileIsEnd()
	{
		return flag;
	}
	//设置要将文件写入文件
	public boolean WriteFile(String path)
	{
		try
		{
			FileOutputStream output=new FileOutputStream(new File(path));
		//infile=new RandomAccessFile(new File("F//java",path),"rw");
		    write=new OutputStreamWriter(output);	
		}
		catch(FileNotFoundException e)
	    {
		e.printStackTrace();
	    }
	    return true;
	}
	//设置关键字
	public void SetKeyWord()
	{
	
	KeyWord[0]="BEGIN";
	KeyWord[1]="CONST";
	KeyWord[2]="DO";
	KeyWord[3]="END";
	KeyWord[4]="IF";
	KeyWord[5]="INTEGER";
	KeyWord[6]="LONG";
	KeyWord[7]="ODD";
	KeyWord[8]="PROCEDURE";
	KeyWord[9]="PROGRAM";
	KeyWord[10]="READ";
	KeyWord[11]="THEN";
	KeyWord[12]="VAR";
	KeyWord[13]="WHILE";
	KeyWord[14]="WRITE";
	}
	//供GetSym取一个字符，每次读一行，存入line缓冲区，line被getsym取空时 再读一行
	public int GetChar()
	{
		
	if(cc==ll)
	{
		if(flag==-1)
		{
			System.out.println("program incomplete");
			return -1;
		}
		ll=0;
		cc=0;
		ch=' ';
		while(ch!='\n'&&ch!='\r')
		{
		try
		{
			flag=in.read();
			if(flag==-1)
			{
				System.out.println("program incomplete");
			    return -1;	
			} 
			
			ch=(char)flag;
			line[ll]=ch;
			ll++;
		}
		catch(IOException e)
			{
				e.printStackTrace();
			}
					
		}
		try
		{
			in.skip(1);
		}
	    catch(IOException e)
		{
		   	e.printStackTrace();
		}
		
		row++;	
	}
	ch=line[cc];
	cc++;
	return 0;
    } 
    //测试
  public String Test()
    {
    	return (strid.toString());
    }
    //取一个词
    public int GetSym()
    {
    	int i,j,k;
    	strid=new StringBuffer();
	while(ch==' '||ch==10||ch==9)	// 忽略空格、换行和TAB 
	{
		if(-1==GetChar()) return -1;
	}
	if(ch>='A'&&ch<='Z')
	{			// 名字或保留字以a..z开头 
		k=0;
		do
		{
			if(k<AL)
			{
				strid.append(ch);
				k++;
			}
			if(-1==GetChar()) return -1;
		}
		while(ch>='A'&&ch<='Z'||ch>='0'&&ch<='9');
		i=0;
		j=NORW-1;
		do // 搜索当前符号是否为保留字 
		{
			k=(i+j)/2;
			if(strid.toString().compareTo(KeyWord[k])<=0)j=k-1;
			if(strid.toString().compareTo(KeyWord[k])>=0)i=k+1;
		}
		while(i<=j);
		
		if(i-1>j) sym=wsym[k]; else sym=IDENT; // 搜索失败则，是名字或数字
	}
	else
	{
		if(ch>='0'&&ch<='9')
		{			// 检测是否为数字：以0..9开头
			k=0;
			num=0;
			sym=USNUMBER;
			do
			{
				num=10*num+ch-'0';
				k++;
				if(-1==GetChar()) return -1;
			}
			while(ch>='0'&&ch<='9'); //获取数字的值
			k--;
			if(k>NMAX)  error();
		}
		else
		{
			if(ch==':')		//检测赋值符号 
			{
				if(-1==GetChar()) return -1;
				if(ch=='=')
				{
					sym=BECOMES;
					if(-1==GetChar()) return -1;
				}
				else
				{
					sym=COLON;	
				}
			}
			else
			{
				if(ch=='<')		//检测小于或小于等于符号
				{
					if(-1==GetChar()) return -1;
					if(ch=='=')
					{
						sym=LEQ;
						if(-1==GetChar()) return -1;
					}
					else if(ch=='>')
					{
                     sym=NLEQ;
					 if(-1==GetChar()) return -1;
					}
					else
					{
						sym=LSS;
					}
				}
				else
				{
					if(ch=='>')		// 检测大于或大于等于符号 
					{
						if(-1==GetChar()) return -1;
						if(ch=='=')
						{
							sym=GEQ;
							if(-1==GetChar()) return -1;
						}
						else
						{
							sym=GTR;
						}
					}
					else
					{
						sym=ssym[ch];		//当符号不满足上述条件时，全部按照单字符符号处理 
						if(-1==GetChar()) return -1;
					}
				}
			}
		}
	}
	return 0;
    }
    //错误输出
    public void error()
    { 
	System.out.println("****Error on row="+row+"****Error on column="+cc);
	err++;
	}
	public  String ReadLineFormConsole()
    {
    	String cstr=new String();
        try{
  	        String temp=new String();
  	        BufferedReader in=new BufferedReader(new InputStreamReader(System.in));
  	        temp=in.readLine();
            cstr=temp;
  	       }
  	    catch(IOException e)
  	    {
  		 e.printStackTrace();
  		}
  		return cstr;	
     }
     //取得错误的总数
     public int GetErrorNum()
     {
     	return err;
     }
     public void PrintResult()
     {
     	
     	    if(sym==IDENT)
			{
				inputstr="("+IDENT+","+strid.toString()+")";
				System.out.println(inputstr);
				try
				{
				write.write(row+inputstr+"\r\n");
				write.flush();	
				}
				catch(IOException e)
				{
					e.printStackTrace();
				}
			}
			else if(sym==USNUMBER)
			{
				inputstr="("+USNUMBER+","+num+")";
				System.out.println(inputstr);
				try
				{
				write.write(row+inputstr+"\r\n");
				write.flush();	
				}
				catch(IOException e)
				{
					e.printStackTrace();
				}
			}
			else
			{
				if(0!=sym)
				{
				inputstr="("+sym+","+0+")";
				System.out.println(inputstr);
				try
				{
				 write.write(row+inputstr+"\r\n");
				 write.flush();	
				}
				catch(IOException e)
				{
					e.printStackTrace();
				}
				}
				
				
			}
     }
    //主要函数

}