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1.1 root 1: /*
2: * Mach Operating System
3: * Copyright (c) 1991,1990 Carnegie Mellon University
4: * All Rights Reserved.
5: *
6: * Permission to use, copy, modify and distribute this software and its
7: * documentation is hereby granted, provided that both the copyright
8: * notice and this permission notice appear in all copies of the
9: * software, derivative works or modified versions, and any portions
10: * thereof, and that both notices appear in supporting documentation.
11: *
12: * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS
13: * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND FOR
14: * ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE.
15: *
16: * Carnegie Mellon requests users of this software to return to
17: *
18: * Software Distribution Coordinator or [email protected]
19: * School of Computer Science
20: * Carnegie Mellon University
21: * Pittsburgh PA 15213-3890
22: *
23: * any improvements or extensions that they make and grant Carnegie the
24: * rights to redistribute these changes.
25: */
26: /*
27: * HISTORY
28: * $Log: db_lex.c,v $
29: * Revision 1.1 1992/03/25 21:45:13 pace
30: * Initial revision
31: *
32: * Revision 2.3 91/02/05 17:06:36 mrt
33: * Changed to new Mach copyright
34: * [91/01/31 16:18:20 mrt]
35: *
36: * Revision 2.2 90/08/27 21:51:10 dbg
37: * Add 'dotdot' token.
38: * [90/08/22 dbg]
39: *
40: * Allow backslash to quote any character into an identifier.
41: * Allow colon in identifier for symbol table qualification.
42: * [90/08/16 dbg]
43: * Reduce lint.
44: * [90/08/07 dbg]
45: * Created.
46: * [90/07/25 dbg]
47: *
48: */
49: /*
50: * Author: David B. Golub, Carnegie Mellon University
51: * Date: 7/90
52: */
53: /*
54: * Lexical analyzer.
55: */
56: #include <ddb/db_lex.h>
57:
58: char db_line[120];
59: char * db_lp, *db_endlp;
60:
61: int
62: db_read_line()
63: {
64: int i;
65:
66: i = db_readline(db_line, sizeof(db_line));
67: if (i == 0)
68: return (0); /* EOI */
69: db_lp = db_line;
70: db_endlp = db_lp + i;
71: return (i);
72: }
73:
74: void
75: db_flush_line()
76: {
77: db_lp = db_line;
78: db_endlp = db_line;
79: }
80:
81: int db_look_char = 0;
82:
83: int
84: db_read_char()
85: {
86: int c;
87:
88: if (db_look_char != 0) {
89: c = db_look_char;
90: db_look_char = 0;
91: }
92: else if (db_lp >= db_endlp)
93: c = -1;
94: else
95: c = *db_lp++;
96: return (c);
97: }
98:
99: void
100: db_unread_char(c)
101: {
102: db_look_char = c;
103: }
104:
105: int db_look_token = 0;
106:
107: void
108: db_unread_token(t)
109: int t;
110: {
111: db_look_token = t;
112: }
113:
114: int
115: db_read_token()
116: {
117: int t;
118:
119: if (db_look_token) {
120: t = db_look_token;
121: db_look_token = 0;
122: }
123: else
124: t = db_lex();
125: return (t);
126: }
127:
128: int db_tok_number;
129: char db_tok_string[TOK_STRING_SIZE];
130:
131: int db_radix = 16;
132:
133: void
134: db_flush_lex()
135: {
136: db_flush_line();
137: db_look_char = 0;
138: db_look_token = 0;
139: }
140:
141: int
142: db_lex()
143: {
144: int c;
145:
146: c = db_read_char();
147: while (c <= ' ' || c > '~') {
148: if (c == '\n' || c == -1)
149: return (tEOL);
150: c = db_read_char();
151: }
152:
153: if (c >= '0' && c <= '9') {
154: /* number */
155: int r, digit;
156:
157: if (c > '0')
158: r = db_radix;
159: else {
160: c = db_read_char();
161: if (c == 'O' || c == 'o')
162: r = 8;
163: else if (c == 'T' || c == 't')
164: r = 10;
165: else if (c == 'X' || c == 'x')
166: r = 16;
167: else {
168: r = db_radix;
169: db_unread_char(c);
170: }
171: c = db_read_char();
172: }
173: db_tok_number = 0;
174: for (;;) {
175: if (c >= '0' && c <= ((r == 8) ? '7' : '9'))
176: digit = c - '0';
177: else if (r == 16 && ((c >= 'A' && c <= 'F') ||
178: (c >= 'a' && c <= 'f'))) {
179: if (c >= 'a')
180: digit = c - 'a' + 10;
181: else if (c >= 'A')
182: digit = c - 'A' + 10;
183: }
184: else
185: break;
186: db_tok_number = db_tok_number * r + digit;
187: c = db_read_char();
188: }
189: if ((c >= '0' && c <= '9') ||
190: (c >= 'A' && c <= 'Z') ||
191: (c >= 'a' && c <= 'z') ||
192: (c == '_'))
193: {
194: db_error("Bad character in number\n");
195: db_flush_lex();
196: return (tEOF);
197: }
198: db_unread_char(c);
199: return (tNUMBER);
200: }
201: if ((c >= 'A' && c <= 'Z') ||
202: (c >= 'a' && c <= 'z') ||
203: c == '_' || c == '\\')
204: {
205: /* string */
206: char *cp;
207:
208: cp = db_tok_string;
209: if (c == '\\') {
210: c = db_read_char();
211: if (c == '\n' || c == -1)
212: db_error("Bad escape\n");
213: }
214: *cp++ = c;
215: while (1) {
216: c = db_read_char();
217: if ((c >= 'A' && c <= 'Z') ||
218: (c >= 'a' && c <= 'z') ||
219: (c >= '0' && c <= '9') ||
220: c == '_' || c == '\\' || c == ':')
221: {
222: if (c == '\\') {
223: c = db_read_char();
224: if (c == '\n' || c == -1)
225: db_error("Bad escape\n");
226: }
227: *cp++ = c;
228: if (cp == db_tok_string+sizeof(db_tok_string)) {
229: db_error("String too long\n");
230: db_flush_lex();
231: return (tEOF);
232: }
233: continue;
234: }
235: else {
236: *cp = '\0';
237: break;
238: }
239: }
240: db_unread_char(c);
241: return (tIDENT);
242: }
243:
244: switch (c) {
245: case '+':
246: return (tPLUS);
247: case '-':
248: return (tMINUS);
249: case '.':
250: c = db_read_char();
251: if (c == '.')
252: return (tDOTDOT);
253: db_unread_char(c);
254: return (tDOT);
255: case '*':
256: return (tSTAR);
257: case '/':
258: return (tSLASH);
259: case '=':
260: return (tEQ);
261: case '%':
262: return (tPCT);
263: case '#':
264: return (tHASH);
265: case '(':
266: return (tLPAREN);
267: case ')':
268: return (tRPAREN);
269: case ',':
270: return (tCOMMA);
271: case '"':
272: return (tDITTO);
273: case '$':
274: return (tDOLLAR);
275: case '!':
276: return (tEXCL);
277: case '<':
278: c = db_read_char();
279: if (c == '<')
280: return (tSHIFT_L);
281: db_unread_char(c);
282: break;
283: case '>':
284: c = db_read_char();
285: if (c == '>')
286: return (tSHIFT_R);
287: db_unread_char(c);
288: break;
289: case -1:
290: return (tEOF);
291: }
292: db_printf("Bad character\n");
293: db_flush_lex();
294: return (tEOF);
295: }
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