C语言词法分析:C#源码
今天继续研究代码解析的算法
这个是算法流程图
有图解可能更直观一点；
以下是c#源码：
1
using System;
2using System.IO;
3using System.Text;
4using System.Windows.Forms;
5using System.Collections;
6
7
namespace CodeFormatter 
{
8
/**//// <summary>
9
/// CodeFormatterFactory 的摘要说明。
10 /// c 代码解析,不支持中文
11
/// </summary>
12 public class CodeFormatterFactory {
13 /**//*源代码*/
14 private string sourceCode = "";
15
16 /**//*C语言所有关键字，共32个*/
17 ArrayList KeyWordList = new ArrayList();
18
19 /**//*运算、限界符*/
20 ArrayList LimitList = new ArrayList();
21
22 /**//*常量表*/
23 ArrayList ConstList = new ArrayList();
24
25 /**//*标识符*/
26 ArrayList IdentifierList = new ArrayList();
27
28 /**//*输出*/
29 ArrayList OutputList = new ArrayList();
30
31 public CodeFormatterFactory() {
32 //
33 // TODO: 在此处添加构造函数逻辑
34 //
35 init();
36 }
37
38 public string SourceCode{
39 get{return this.sourceCode;}
40 set{this.sourceCode =value;}
41 }
42
43 public string ParseMessages{
44 get{
45 string pm = "";
46
47 IEnumerator ie = this.OutputList.GetEnumerator();
48 while ( ie.MoveNext() )
49 pm += ie.Current.ToString() + "\r\n";
50 return pm;
51 }
52 }
53
54 private void init() {
55 /**//*C语言所有关键字，共32个*/
56 string[] key=new string[]{" ","auto","break","case","char","const","continue","default","do","double",
57 "else","enum","extern","float","for","goto","if","int","long","register",
58 "return","short","signed","sizeof","static","struct","switch","typedef",
59 "union","unsigned","void","volatile","while"};
60 /**//*运算、限界符*/
61 string[] limit=new string[]{" ","(",")","[","]","->",".","!","++","--","&","~",
62 "*","/","%","+","-","<<",">>","<","<=",">",">=","==","!=","&&","||",
63 "=","+=","-=","*=","/=",",",";","{","}","#","_","'"};
64
65 this.KeyWordList.Clear();
66 this.KeyWordList.TrimToSize();
67 for(int i=1;i<key.Length;i++)
68 this.KeyWordList.Add(key[i]);
69
70 this.LimitList.Clear();
71 this.LimitList.TrimToSize();
72 for(int i=1;i<limit.Length;i++)
73 this.LimitList.Add(limit[i]);
74
75 this.ConstList.Clear();
76 this.ConstList.TrimToSize();
77
78 this.IdentifierList.Clear();
79 this.IdentifierList.TrimToSize();
80
81 this.OutputList.Clear();
82 this.OutputList.TrimToSize();
83 }
84
85 /**//*******************************************
86 * 十进制转二进制函数
87 *******************************************/
88 private string dtb(string buf){
89 int[] temp= new int[20];
90 string binary = "";
91 int val=0,i=0;
92
93 /**//*先将字符转化为十进制数*/
94 try{
95 val = Convert.ToInt32(buf);
96 }catch{
97 val = 0;
98 }
99
100 if(val==0) {
101 return(val.ToString());
102 }
103
104 i=0;
105 while(val!=0) {
106 temp[i++]=val%2;
107 val/=2;
108 }
109
110 binary = "";
111 for(int j=0;j<=i-1;j++)
112 binary += (char)(temp[i-j-1]+48);
113
114 return(binary);
115 }
116
117 /**//*******************************************
118 * 根据不同命令查表或造表函数
119 *******************************************/
120 private int find(string buf,int type,int command){
121 int number=0;
122 string temp;
123
124 IEnumerator ie = null;
125 ArrayList al = null;
126 switch(type){
127 case 1://关键字表
128 ie = this.KeyWordList.GetEnumerator();
129 break;
130 case 2://标识符表
131 ie = this.IdentifierList.GetEnumerator();
132 break;
133 case 3://常数表
134 ie = this.ConstList.GetEnumerator();
135 break;
136 case 4://运算、限界符表
137 ie = this.LimitList.GetEnumerator();
138 break;
139 }
140
141 if(ie!=null)
142 while (ie.MoveNext()){
143 temp = ie.Current.ToString();
144 if(temp.Trim().ToLower()==buf.Trim().ToLower()){
145 return number;
146 }
147 number ++;
148 }
149
150 if(command==1){
151 /**//*找不到，当只需查表，返回0，否则还需造表*/
152 return 0;
153 }
154
155 switch(type){
156 case 1: al = this.KeyWordList;break;
157 case 2: al = this.IdentifierList;break;
158 case 3: al = this.ConstList;break;
159 case 4: al = this.LimitList;break;
160 }
161 if(al!=null)
162 al.Add(buf);
163
164 return number + 1;
165 }
166 /**//*******************************************
167 * 数字串处理函数
168 *******************************************/
169 private void cs_manage(string buffer){
170 string binary = dtb(buffer);
171 int result = find(binary,3,2);
172 this.OutputList.Add(String.Format("{0}\t\t\t3\t\t\t{1}",buffer,result));
173 }
174
175 /**//*******************************************
176 * 字符串处理函数
177 *******************************************/
178 private void ch_manage(string buffer) {
179 int result = find(buffer,1,1);
180 if(result!=0){
181 this.OutputList.Add(String.Format("{0}\t\t\t1\t\t\t{1}",buffer,result));
182 }else{
183 result = find(buffer,2,2);
184 this.OutputList.Add(String.Format("{0}\t\t\t2\t\t\t{1}",buffer,result));
185 }
186 }
187
188 /**//*******************************************
189 * 出错处理函数
190 *******************************************/
191 private void er_manage(char error,int lineno) {
192 this.OutputList.Add(String.Format("错误关键字: {0} ，所在行: {1}",error,lineno));
193 }
194
195 /**//*******************************************
196 * 转换Char数组为string
197 ******************************************/
198 private string joinString(char[] array,int Length){
199 string s = "";
200 if(array.Length>0)
201 for(int i=0;i<Length;i++){
202 if(array[i]!='\0') {
203 s+=array[i];
204 }else{
205 break;
206 }
207 }
208 return s;
209 }
210
211 private char getchc(ref int n){
212 char[] c = sourceCode.ToCharArray();
213 if(n<c.Length){
214 char r = c[n];
215 n++;
216 return r;
217 }
218 return sourceCode[sourceCode.Length-1];
219 }
220 /**//*******************************************
221 * 扫描程序
222 ********************************************/
223 public void Parse() {
224 //StreamWriter fpout = null;
225 char ch ;
226 int i=0,line=1;
227 int count,result,errorno=0;
228 char[] array = new char[30];
229 string word= "";
230
231 /**//*按字符依次扫描源程序，直至结束*/
232 int n = 0;
233
234 while(n<sourceCode.Length-1){
235 i = 0;
236 ch = getchc(ref n);
237 /**//*以字母开头*/
238 if(((ch>='A')&&(ch<='Z'))||((ch>='a')&&(ch<='z'))||(ch=='_')) {
239 while(((ch>='A')&&(ch<='Z'))||((ch>='a')&&(ch<='z'))||(ch=='_')||((ch>='0')&&(ch<='9'))) {
240 array[i++]=ch;
241 ch = getchc(ref n);
242 }
243 array[i++] = '\0';
244 word = joinString(array,array.Length);
245 ch_manage(word);
246 if(n<sourceCode.Length)n--;
247 }else if(ch>='0'&&ch<='9') {
248 /**//*以数字开头*/
249 while(ch>='0'&&ch<='9') {
250 array[i++]=ch;
251 ch = getchc(ref n);
252 }
253 array[i++] = '\0';
254 word=joinString(array,array.Length);
255 cs_manage(word);
256 if(n<sourceCode.Length)n--;
257 }
258 else if((ch==' ')||(ch=='\t'))
259 /**//*消除空格符和水平制表符*/
260 ;
261 else if(ch=='\n')
262 /**//*消除回车并记录行数*/
263 line++;
264 else if(ch=='/') {
265 /**//*消除注释*/
266 ch = getchc(ref n);
267 if(ch=='=') {
268 /**//*判断是否为‘/=’符号*/
269 this.OutputList.Add(String.Format("/=\t\t\t4\t\t\t32"));
270 }
271 else if(ch!='*') {
272 /**//*若为除号，写入输出*/
273 this.OutputList.Add(String.Format("/\t\t\t4\t\t\t13"));
274 n--;
275 } else if(ch=='*') {
276 /**//*若为注释的开始，消除包含在里面的所有字符*/
277 count=0;
278 ch = getchc(ref n);
279 while(count!=2) {
280 /**//*当扫描到‘*’且紧接着下一个字符为‘/’才是注释的结束*/
281 count=0;
282 while(ch!='*')
283 ch = getchc(ref n);
284 count++;
285 ch = getchc(ref n);
286 if(ch=='/')
287 count++;
288 else
289 ch = getchc(ref n);
290 }
291 }
292 }
293 else if(ch=='"') {
294 /**//*消除包含在双引号中的字符串常量*/
295 this.OutputList.Add(String.Format("{0}\t\t\t4\t\t\t37",ch));
296 while(ch!='"')
297 ch = getchc(ref n);
298 this.OutputList.Add(String.Format("{0}\t\t\t4\t\t\t37",ch));
299 }
300 else {
301 /**//*首字符为其它字符,即运算限界符或非法字符*/
302 array[0]=ch;
303 /**//*再读入下一个字符，判断是否为双字符运算、限界符*/
304 ch = getchc(ref n);
305 /**//*若该字符非结束符*/
306 if(n<sourceCode.Length) {
307 array[1]=ch;
308 array[2] = '\0';
309 word = joinString(array,2);
310 result=find(word,4,1); /**//*先检索是否为双字符运算、限界符*/
311 if(result==0) {
312 /**//*若不是*/
313 array[2] = '\0';
314 word = joinString(array,1);
315 result=find(word,4,1);
316 /**//*检索是否为单字符运算、限界符*/
317 if(result==0) {
318 /**//*若还不是，则为非法字符*/
319 er_manage(array[0],line);
320 errorno++;
321 n--;
322 }
323 else {
324 /**//*若为单字符运算、限界符，写入输出并将扫描指针回退一个字符*/
325 this.OutputList.Add(String.Format("{0}\t\t\t4\t\t\t{1}\t",word,result));
326 n--;
327 }
328 }
329 else {
330 /**//*若为双字符运算、限界符，写输出*/
331 this.OutputList.Add(String.Format("{0}\t\t\t4\t\t\t{1}",word,result));
332 }
333 }
334 else {
335 /**//*若读入的下一个字符为结束符*/
336 array[2] = '\0';
337 word = joinString(array,1);
338 /**//*只考虑是否为单字符运算、限界符*/
339 result=find(word,4,1);
340 /**//*若不是，转出错处理*/
341 if(result==0)
342 er_manage(array[0],line);
343 else {
344 /**//*若是，写输出*/
345 this.OutputList.Add(String.Format("{0}\t\t\t4\t\t\t{1}",word,result));
346 }
347 }
348 }
349 ch = getchc(ref n);
350 }
351 /**//*报告错误字符个数*/
352 this.OutputList.Add(String.Format("\n共有 {0} 个错误.\n",errorno));
353 }
354
355 }
356
}
357
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代码可能似曾相识，因为我是参考的一篇C的代码；
这里下载工程源码（带C代码）
2005年4月22日 S.F.
出处：http://www.cnblogs.com/chinasf/archive/2005/04/22/143449.html