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4b365fcd KM |
1 | static char sccsid[] = "@(#)lexi.c 4.1 (Berkeley) %G%"; |
2 | ||
3 | /* | |
4 | ||
5 | Copyright (C) 1976 | |
6 | by the | |
7 | Board of Trustees | |
8 | of the | |
9 | University of Illinois | |
10 | ||
11 | All rights reserved | |
12 | ||
13 | ||
14 | NAME: | |
15 | lexi | |
16 | ||
17 | FUNCTION: | |
18 | This is the token scanner for indent | |
19 | ||
20 | ALGORITHM: | |
21 | 1) Strip off intervening blanks and/or tabs. | |
22 | 2) If it is an alphanumeric token, move it to the token buffer "token". | |
23 | Check if it is a special reserved word that indent will want to | |
24 | know about. | |
25 | 3) Non-alphanumeric tokens are handled with a big switch statement. A | |
26 | flag is kept to remember if the last token was a "unary delimiter", | |
27 | which forces a following operator to be unary as opposed to binary. | |
28 | ||
29 | PARAMETERS: | |
30 | None | |
31 | ||
32 | RETURNS: | |
33 | An integer code indicating the type of token scanned. | |
34 | ||
35 | GLOBALS: | |
36 | buf_ptr = | |
37 | had_eof | |
38 | last_u_d = Set to true iff this token is a "unary delimiter" | |
39 | ||
40 | CALLS: | |
41 | fill_buffer | |
42 | printf (lib) | |
43 | ||
44 | CALLED BY: | |
45 | main | |
46 | ||
47 | NOTES: | |
48 | Start of comment is passed back so that the comment can be scanned by | |
49 | pr_comment. | |
50 | ||
51 | Strings and character literals are returned just like identifiers. | |
52 | ||
53 | HISTORY: | |
54 | initial coding November 1976 D A Willcox of CAC | |
55 | 1/7/77 D A Willcox of CAC Fix to provide proper handling | |
56 | of "int a -1;" | |
57 | ||
58 | */\f | |
59 | ||
60 | /* Here we have the token scanner for indent. It scans off one token and | |
61 | puts it in the global variable "token". It returns a code, indicating the | |
62 | type of token scanned. */ | |
63 | ||
64 | #include "indent_globs.h"; | |
65 | #include "indent_codes.h"; | |
66 | ||
67 | ||
68 | ||
69 | #define alphanum 1 | |
70 | #define opchar 3 | |
71 | ||
72 | struct templ { | |
73 | char *rwd; | |
74 | int rwcode; | |
75 | }; | |
76 | ||
77 | struct templ specials[] = | |
78 | { | |
79 | "switch", 1, | |
80 | "case", 2, | |
81 | "struct", 3, | |
82 | "default", 2, | |
83 | "int", 4, | |
84 | "char", 4, | |
85 | "float", 4, | |
86 | "double", 4, | |
87 | "long", 4, | |
88 | "short", 4, | |
89 | "typdef", 4, | |
90 | "unsigned", 4, | |
91 | "register", 4, | |
92 | "static", 4, | |
93 | "global", 4, | |
94 | "extern", 4, | |
95 | "if", 5, | |
96 | "while", 5, | |
97 | "for", 5, | |
98 | "else", 6, | |
99 | "do", 6, | |
100 | "sizeof", 0, | |
101 | 0, 0 | |
102 | }; | |
103 | ||
104 | char chartype[128] = | |
105 | { /* this is used to facilitate the decision of what type | |
106 | (alphanumeric, operator) each character is */ | |
107 | 0, 0, 0, 0, 0, 0, 0, 0, | |
108 | 0, 0, 0, 0, 0, 0, 0, 0, | |
109 | 0, 0, 0, 0, 0, 0, 0, 0, | |
110 | 0, 0, 0, 0, 0, 0, 0, 0, | |
111 | 0, 3, 0, 0, 0, 3, 3, 0, | |
112 | 0, 0, 3, 3, 0, 3, 3, 3, | |
113 | 1, 1, 1, 1, 1, 1, 1, 1, | |
114 | 1, 1, 0, 0, 3, 3, 3, 3, | |
115 | 0, 1, 1, 1, 1, 1, 1, 1, | |
116 | 1, 1, 1, 1, 1, 1, 1, 1, | |
117 | 1, 1, 1, 1, 1, 1, 1, 1, | |
118 | 1, 1, 1, 0, 0, 0, 3, 1, | |
119 | 0, 1, 1, 1, 1, 1, 1, 1, | |
120 | 1, 1, 1, 1, 1, 1, 1, 1, | |
121 | 1, 1, 1, 1, 1, 1, 1, 1, | |
122 | 1, 1, 1, 0, 3, 0, 3, 0 | |
123 | }; | |
124 | ||
125 | int last_nl = true; | |
126 | /* this is true if the last thing scanned was a newline */ | |
127 | ||
128 | ||
129 | ||
130 | int lexi () { | |
131 | register char *tok; | |
132 | /* local pointer to next char in token */ | |
133 | register int i; | |
134 | /* local loop counter */ | |
135 | register char *j; | |
136 | /* used for searching thru list of reserved words */ | |
137 | int unary_delim; | |
138 | /* this is set to 1 if the current token forces a following operator to be | |
139 | unary */ | |
140 | static int last_code; | |
141 | /* the last token type returned */ | |
142 | static int l_struct; | |
143 | /* set to 1 if the last token was 'struct' */ | |
144 | int found_it; | |
145 | int code; /* internal code to be returned */ | |
146 | char qchar; /* the delimiter character for a string */ | |
147 | ||
148 | tok = token; /* point to start of place to save token */ | |
149 | unary_delim = false; | |
150 | col_1 = last_nl; /* tell world that this token started in column | |
151 | 1 iff the last thing scanned was nl */ | |
152 | last_nl = false; | |
153 | ||
154 | while (*buf_ptr == ' ' || *buf_ptr == '\t') { | |
155 | /* get rid of blanks */ | |
156 | col_1 = false; /* leading blanks imply token is not in column 1 | |
157 | */ | |
158 | if (++buf_ptr >= buf_end) | |
159 | fill_buffer (); | |
160 | } | |
161 | ||
162 | /*----------------------------------------------------------*\ | |
163 | | Scan an alphanumeric token | |
164 | \*----------------------------------------------------------*/ | |
165 | ||
166 | if (chartype[*buf_ptr & 0177] == alphanum) { | |
167 | /* we have a character or number */ | |
168 | while (chartype[*buf_ptr & 0177] == alphanum) { | |
169 | /* copy it over */ | |
170 | *tok++ = *buf_ptr++; | |
171 | if (buf_ptr >= buf_end) | |
172 | fill_buffer (); | |
173 | } | |
174 | ||
175 | *tok++ = '\0'; | |
176 | ||
177 | if (l_struct) { /* if last token was 'struct', then this token | |
178 | should be treated as a declaration */ | |
179 | l_struct = false; | |
180 | last_code = ident; | |
181 | last_u_d = true; | |
182 | return (decl); | |
183 | } | |
184 | ||
185 | last_u_d = false; /* operator after indentifier is binary */ | |
186 | ||
187 | for (i = 0; specials[i].rwd != 0; ++i) { | |
188 | /* this loop will check if the token is a keyword. if so, a following | |
189 | operator is unary */ | |
190 | last_code = ident; /* remember that this is the code we will return | |
191 | */ | |
192 | j = specials[i].rwd; | |
193 | /* point at ith reserved word */ | |
194 | tok = token; /* point at scanned toekn */ | |
195 | found_it = true; /* set to false if not found */ | |
196 | do { | |
197 | if (*tok++ != *j) { | |
198 | found_it = false; | |
199 | break; | |
200 | } | |
201 | } while (*j++); | |
202 | ||
203 | if (found_it) { /* we have a keyword */ | |
204 | last_u_d = true; | |
205 | switch (specials[i].rwcode) { | |
206 | case 1: /* it is a switch */ | |
207 | return (swstmt); | |
208 | case 2: /* a case or default */ | |
209 | return (casestmt); | |
210 | ||
211 | case 3: /* a "struct" */ | |
212 | l_struct = true; | |
213 | /* Next time around, we will want to know that we have had | |
214 | a 'struct' */ | |
215 | case 4: /* one of the declaration keywords */ | |
216 | if(p_l_follow) break; /* inside parens: cast */ | |
217 | last_code = decl; | |
218 | return (decl); | |
219 | ||
220 | case 5: /* if, while, for */ | |
221 | return (sp_paren); | |
222 | ||
223 | case 6: /* do, else */ | |
224 | return (sp_nparen); | |
225 | ||
226 | default: /* all others are treated like any other | |
227 | identifier */ | |
228 | return (ident); | |
229 | } /* end of switch */ | |
230 | } /* end of if (found_it) */ | |
231 | ||
232 | } | |
233 | ||
234 | if (last_code == decl) /* if this is a declared variable, then | |
235 | following sign is unary */ | |
236 | last_u_d = true; /* will make "int a -1" work */ | |
237 | last_code = ident; | |
238 | return (ident); /* the ident is not in the list */ | |
239 | } /* end of procesing for alpanum character */ | |
240 | ||
241 | ||
242 | ||
243 | /*----------------------------------------------------------*\ | |
244 | | Scan a non-alphanumeric token | |
245 | \*----------------------------------------------------------*/ | |
246 | ||
247 | *tok++ = *buf_ptr; /* if it is only a one-character token, it is | |
248 | moved here */ | |
249 | *tok = '\0'; | |
250 | if (++buf_ptr >= buf_end) | |
251 | fill_buffer (); | |
252 | ||
253 | switch (*token) { | |
254 | case '\n': | |
255 | unary_delim = last_u_d; | |
256 | last_nl = true; /* remember that we just had a newline */ | |
257 | code = (had_eof ? 0 : newline); | |
258 | /* if data has been exausted, the newline is a dummy, and we should | |
259 | return code to stop */ | |
260 | break; | |
261 | ||
262 | case '\'': /* start of quoted character */ | |
263 | qchar = '\''; /* remember final delimiter */ | |
264 | goto copy_lit; /* and go to common literal code */ | |
265 | ||
266 | case '"': /* start of string */ | |
267 | qchar = '"'; | |
268 | ||
269 | copy_lit: | |
270 | do { /* copy the string */ | |
271 | while (1) { /* move one character or [/<char>]<char> */ | |
272 | if (*buf_ptr == '\n') { | |
273 | /* check for unterminated literal */ | |
274 | printf ("%d: Unterminated literal\n", line_no); | |
275 | goto stop_lit; | |
276 | /* Don't copy any more */ | |
277 | } | |
278 | ||
279 | *tok = *buf_ptr++; | |
280 | if (buf_ptr >= buf_end) | |
281 | fill_buffer (); | |
282 | if (had_eof || ((tok - token) > (bufsize - 2))) { | |
283 | printf ("Unterminated literal\n"); | |
284 | ++tok; | |
285 | goto stop_lit; | |
286 | /* get outof literal copying loop */ | |
287 | } | |
288 | ||
289 | if (*tok == '\\') { | |
290 | /* if escape, copy extra char */ | |
291 | if (*buf_ptr == '\n') | |
292 | /* check for escaped newline */ | |
293 | ++line_no; | |
294 | *(++tok) = *buf_ptr++; | |
295 | ++tok; /* we must increment this again because we | |
296 | copied two chars */ | |
297 | if (buf_ptr >= buf_end) | |
298 | fill_buffer (); | |
299 | } | |
300 | else | |
301 | break; /* we copied one character */ | |
302 | } /* end of while (1) */ | |
303 | } while (*tok++ != qchar); | |
304 | ||
305 | stop_lit: | |
306 | code = ident; | |
307 | break; | |
308 | ||
309 | case ('('): | |
310 | case ('['): | |
311 | unary_delim = true; | |
312 | code = lparen; | |
313 | break; | |
314 | ||
315 | case (')'): | |
316 | case (']'): | |
317 | code = rparen; | |
318 | break; | |
319 | ||
320 | case '#': | |
321 | unary_delim = last_u_d; | |
322 | code = preesc; | |
323 | break; | |
324 | ||
325 | case '?': | |
326 | unary_delim = true; | |
327 | code = question; | |
328 | break; | |
329 | ||
330 | case (':'): | |
331 | code = colon; | |
332 | unary_delim = true; | |
333 | break; | |
334 | ||
335 | case (';'): | |
336 | unary_delim = true; | |
337 | code = semicolon; | |
338 | break; | |
339 | ||
340 | case ('{'): | |
341 | unary_delim = true; | |
342 | code = lbrace; | |
343 | break; | |
344 | ||
345 | case ('}'): | |
346 | unary_delim = true; | |
347 | code = rbrace; | |
348 | break; | |
349 | ||
350 | case 014: /* a form feed */ | |
351 | unary_delim = last_u_d; | |
352 | last_nl = true; /* remember this so we can set 'col_1' right */ | |
353 | code = form_feed; | |
354 | break; | |
355 | ||
356 | case (','): | |
357 | unary_delim = true; | |
358 | code = comma; | |
359 | break; | |
360 | ||
361 | case '.': | |
362 | unary_delim = false; | |
363 | code = period; | |
364 | break; | |
365 | ||
366 | case '-': | |
367 | case '+': /* check for -, +, --, ++ */ | |
368 | code = (last_u_d ? unary_op : binary_op); | |
369 | unary_delim = true; | |
370 | ||
371 | if (*buf_ptr == token[0]) { | |
372 | /* check for doubled character */ | |
373 | *tok++ = *buf_ptr++; | |
374 | /* buffer overflow will be checked at end of loop */ | |
375 | if (last_code == ident || last_code == rparen) { | |
376 | code = (last_u_d ? unary_op : postop); | |
377 | /* check for following ++ or -- */ | |
378 | unary_delim = false; | |
379 | } | |
380 | } | |
381 | else | |
382 | if (*buf_ptr == '>' || *buf_ptr == '=') | |
383 | /* check for operator -> or += */ | |
384 | *tok++ = *buf_ptr++; | |
385 | /* buffer overflow will be checked at end of switch */ | |
386 | ||
387 | break; | |
388 | ||
389 | case '=': | |
390 | if (chartype[*buf_ptr] == opchar) { | |
391 | /* we have two char assignment */ | |
392 | *tok++ = *buf_ptr; | |
393 | /* move second character */ | |
394 | if (++buf_ptr >= buf_end) | |
395 | fill_buffer (); | |
396 | } | |
397 | ||
398 | code = binary_op; | |
399 | unary_delim = true; | |
400 | if (token[1] != '<' && token[1] != '>') | |
401 | /* check for possible 3 char operator */ | |
402 | break; | |
403 | /* can drop thru!!! */ | |
404 | ||
405 | case '>': | |
406 | case '<': | |
407 | case '!': /* ops like <, <<, <=, !=, etc */ | |
408 | if (*buf_ptr == '>' || *buf_ptr == '<' || *buf_ptr == '=') { | |
409 | *tok++ = *buf_ptr; | |
410 | if (++buf_ptr >= buf_end) | |
411 | fill_buffer (); | |
412 | } | |
413 | ||
414 | if (*buf_ptr == '=') | |
415 | *tok++ = *buf_ptr++; | |
416 | code = (last_u_d ? unary_op : binary_op); | |
417 | unary_delim = true; | |
418 | break; | |
419 | ||
420 | default: | |
421 | if (token[0] == '/' && *buf_ptr == '*') { | |
422 | /* it is start of comment */ | |
423 | *tok++ = '*'; | |
424 | ||
425 | if (++buf_ptr >= buf_end) | |
426 | fill_buffer (); | |
427 | ||
428 | code = comment; | |
429 | unary_delim = last_u_d; | |
430 | break; | |
431 | } | |
432 | ||
433 | while (*(tok - 1) == *buf_ptr || *buf_ptr=='=') { | |
434 | /* handle ||, &&, etc, and also things as in int *****i */ | |
435 | *tok++ = *buf_ptr; | |
436 | if (++buf_ptr >= buf_end) | |
437 | fill_buffer (); | |
438 | } | |
439 | ||
440 | ||
441 | code = (last_u_d ? unary_op : binary_op); | |
442 | unary_delim = true; | |
443 | ||
444 | ||
445 | } /* end of switch */ | |
446 | ||
447 | if (code != newline) { | |
448 | l_struct = false; | |
449 | last_code = code; | |
450 | } | |
451 | ||
452 | if (buf_ptr >= buf_end) /* check for input buffer empty */ | |
453 | fill_buffer (); | |
454 | last_u_d = unary_delim; | |
455 | *tok = '\0'; /* null terminate the token */ | |
456 | return (code); | |
457 | }; |