|
1
30 package org.objectweb.asm.jbfc;
31
32 import java.io.IOException  ;
33 import java.io.Reader ;
34 import java.util.Stack ;
35
36 import org.objectweb.asm.ClassVisitor;
37 import org.objectweb.asm.Label;
38 import org.objectweb.asm.MethodVisitor;
39 import org.objectweb.asm.Opcodes;
40
41
47 public class BFCompiler implements Opcodes {
48
49 private static final int V_IS = 0;
50
51 private static final int V_OS = 1;
52
53 private static final int V_P = 2;
54
55 private static final int V_D = 3;
56
57 public void compile(
58 Reader r,
59 String className,
60 String sourceName,
61 ClassVisitor cv) throws IOException
62 {
63 cv.visit(Opcodes.V1_3,
64 ACC_PUBLIC,
65 className.replace('.', '/'),
66 null,
67 "java/lang/Object",
68 null);
69 cv.visitSource(sourceName, null);
70
71 MethodVisitor mv;
72 {
73 mv = cv.visitMethod(ACC_PUBLIC, "<init>", "()V", null, null);
74 mv.visitCode();
75 mv.visitVarInsn(ALOAD, 0);
76 mv.visitMethodInsn(INVOKESPECIAL,
77 "java/lang/Object",
78 "<init>",
79 "()V");
80 mv.visitInsn(RETURN);
81 mv.visitMaxs(1, 1);
82 mv.visitEnd();
83 }
84
85 {
86
92 mv = cv.visitMethod(ACC_PUBLIC + ACC_STATIC,
93 "main",
94 "([Ljava/lang/String;)V",
95 null,
96 null);
97 mv.visitCode();
98
99 mv.visitFieldInsn(GETSTATIC,
100 "java/lang/System",
101 "in",
102 "Ljava/io/InputStream;");
103 mv.visitVarInsn(ASTORE, V_IS);
104
105 mv.visitFieldInsn(GETSTATIC,
106 "java/lang/System",
107 "out",
108 "Ljava/io/PrintStream;");
109 mv.visitVarInsn(ASTORE, V_OS);
110
111 mv.visitInsn(ICONST_0);
112 mv.visitVarInsn(ISTORE, V_P);
113
114 mv.visitIntInsn(SIPUSH, 30000);
115 mv.visitIntInsn(NEWARRAY, T_INT);
116 mv.visitVarInsn(ASTORE, V_D);
117
118 Stack labels = new Stack ();
119
120 int d = 0;
121 int p = 0;
122
123 int c;
124 while ((c = r.read()) != -1) {
125 switch (c) {
126 case '>':
127 d = storeD(mv, d);
128 p++;
129 break;
130
131 case '<':
132 d = storeD(mv, d);
133 p--;
134 break;
135
136 case '+':
137 p = storeP(mv, p);
138 d++;
139 break;
140
141 case '-':
142 p = storeP(mv, p);
143 d--;
144 break;
145
146 case '.':
147 p = storeP(mv, p);
148 d = storeD(mv, d);
149
150 mv.visitVarInsn(ALOAD, V_OS);
151 mv.visitVarInsn(ALOAD, V_D);
152 mv.visitVarInsn(ILOAD, V_P);
153 mv.visitInsn(IALOAD);
154 mv.visitMethodInsn(INVOKEVIRTUAL,
155 "java/io/OutputStream",
156 "write",
157 "(I)V");
158 break;
159
160 case ',':
161 p = storeP(mv, p);
162 d = storeD(mv, d);
163
164 mv.visitVarInsn(ALOAD, V_D);
165 mv.visitVarInsn(ILOAD, V_P);
166 mv.visitVarInsn(ALOAD, V_IS);
167 mv.visitMethodInsn(INVOKEVIRTUAL,
168 "java/io/InputStream",
169 "read",
170 "()I");
171 mv.visitInsn(IASTORE);
172 break;
173
174 case '[':
175 p = storeP(mv, p);
176 d = storeD(mv, d);
177
178 Label ls = new Label();
179 Label le = new Label();
180 labels.push(ls);
181 labels.push(le);
182 mv.visitJumpInsn(GOTO, le);
183 mv.visitLabel(ls);
184 break;
185
186 case ']':
187 p = storeP(mv, p);
188 d = storeD(mv, d);
189
190 mv.visitLabel((Label) labels.pop());
191 mv.visitVarInsn(ALOAD, V_D);
192 mv.visitVarInsn(ILOAD, V_P);
193 mv.visitInsn(IALOAD);
194 mv.visitJumpInsn(IFNE, (Label) labels.pop());
195 break;
196 }
197 }
198
199 mv.visitInsn(RETURN);
200
201 mv.visitMaxs(1, 1);
202 mv.visitEnd();
203 }
204
205 }
206
207 private int storeD(MethodVisitor mv, int d) {
208 if (d != 0) {
209 mv.visitVarInsn(ALOAD, V_D);
210 mv.visitVarInsn(ILOAD, V_P);
211 mv.visitInsn(DUP2);
212 mv.visitInsn(IALOAD);
213 mv.visitIntInsn(SIPUSH, d);
214 mv.visitInsn(IADD);
215 mv.visitInsn(IASTORE);
216 }
217 return 0;
218 }
219
220 private int storeP(MethodVisitor mv, int p) {
221 if (p != 0) {
222 mv.visitIincInsn(V_P, p);
223 }
224 return 0;
225 }
226
227 }
228 |
Popular Tags |
Java API By Example, From Geeks To Geeks.