10 #define MAX(a, b) ((a) < (b) ? (b) : (a))
11 #define LEN(a) (sizeof(a) / sizeof((a)[0]))
13 /* regular expressions atoms */
14 #define RA_CHR '\0' /* character literal */
15 #define RA_BEG '^' /* string start */
16 #define RA_END '$' /* string end */
17 #define RA_ANY '.' /* any character */
18 #define RA_BRK '[' /* bracket expression */
19 #define RA_WBEG '<' /* word start */
20 #define RA_WEND '>' /* word end */
22 /* regular expression node types */
23 #define RN_ATOM '\0' /* regular expression */
24 #define RN_CAT 'c' /* concatenation */
25 #define RN_ALT '|' /* alternate expressions */
26 #define RN_GRP '(' /* pattern group */
28 /* regular expression program instructions */
29 #define RI_ATOM '\0' /* regular expression */
30 #define RI_FORK 'f' /* fork the execution */
31 #define RI_JUMP 'j' /* jump to the given instruction */
32 #define RI_MARK 'm' /* mark the current position */
33 #define RI_MATCH 'q' /* the pattern is matched */
35 /* regular expression atom */
37 int ra
; /* atom type (RA_*) */
38 char *s
; /* atom argument */
41 /* regular expression instruction */
43 int ri
; /* instruction type (RI_*) */
44 struct ratom ra
; /* regular expression atom (RI_ATOM) */
45 int a1
, a2
; /* destination of RE_FORK and RI_JUMP */
46 int mark
; /* mark (RI_MARK) */
49 /* regular expression program */
51 struct rinst
*p
; /* the program */
52 int n
; /* number of instructions */
53 int grpcnt
; /* number of groups */
54 int flg
; /* regcomp() flags */
57 /* regular expression matching state */
59 int mark
[NGRPS
* 2]; /* marks for RI_MARK */
60 int pc
; /* program counter */
61 char *s
; /* the current position in the string */
62 char *o
; /* the beginning of the string */
63 int flg
; /* flags passed to regcomp() and regexec() */
66 /* regular expression tree; used for parsing */
68 int rn
; /* node type (RN_*) */
69 struct ratom ra
; /* regular expression atom (RN_ATOM) */
70 int mincnt
, maxcnt
; /* number of repetitions */
71 struct rnode
*c1
, *c2
; /* children */
74 static struct rnode
*rnode_make(int rn
, struct rnode
*c1
, struct rnode
*c2
)
76 struct rnode
*rnode
= malloc(sizeof(*rnode
));
77 memset(rnode
, 0, sizeof(*rnode
));
86 static void rnode_free(struct rnode
*rnode
)
89 rnode_free(rnode
->c1
);
91 rnode_free(rnode
->c2
);
96 static int uc_len(char *s
)
98 int c
= (unsigned char) s
[0];
99 if (~c
& 0x80) /* ASCII */
101 if (~c
& 0x40) /* invalid UTF-8 */
112 static int uc_dec(char *s
)
117 return (unsigned char) *s
;
118 result
= (0x3f >> --l
) & (unsigned char) *s
++;
120 result
= (result
<< 6) | ((unsigned char) *s
++ & 0x3f);
124 static void ratom_copy(struct ratom
*dst
, struct ratom
*src
)
129 int len
= strlen(src
->s
);
130 dst
->s
= malloc(len
+ 1);
131 memcpy(dst
->s
, src
->s
, len
+ 1);
135 static int brk_len(char *s
)
138 if (s
[n
] == '^') /* exclusion mark */
140 if (s
[n
] == ']') /* handling []a] */
142 while (s
[n
] && s
[n
] != ']') {
143 if (s
[n
] == '[' && (s
[n
+ 1] == ':' || s
[n
+ 1] == '='))
144 while (s
[n
] && s
[n
] != ']')
149 return s
[n
] == ']' ? n
+ 1 : n
;
152 static void ratom_readbrk(struct ratom
*ra
, char **pat
)
154 int len
= brk_len(*pat
);
156 ra
->s
= malloc(len
+ 1);
157 memcpy(ra
->s
, *pat
, len
);
162 static void ratom_read(struct ratom
*ra
, char **pat
)
165 switch ((unsigned char) **pat
) {
179 ratom_readbrk(ra
, pat
);
182 if ((*pat
)[1] == '<' || (*pat
)[1] == '>') {
183 ra
->ra
= (*pat
)[1] == '<' ? RA_WBEG
: RA_WEND
;
192 memcpy(ra
->s
, *pat
, len
);
198 static char *uc_beg(char *beg
, char *s
)
200 while (s
> beg
&& (((unsigned char) *s
) & 0xc0) == 0x80)
205 static int isword(char *s
)
207 int c
= (unsigned char) s
[0];
208 return isalnum(c
) || c
== '_' || c
> 127;
211 static char *brk_classes
[][2] = {
212 {":alnum:", "a-zA-Z0-9"},
213 {":alpha:", "a-zA-Z"},
217 {":print:", "\x20-\x7e"},
218 {":punct:", "][!\"#$%&'()*+,./:;<=>?@\\^_`{|}~-"},
219 {":space:", " \t\r\n\v\f"},
221 {":word:", "a-zA-Z0-9_"},
222 {":xdigit:", "a-fA-F0-9"},
225 static int brk_match(char *brk
, int c
, int flg
)
229 int not = brk
[0] == '^';
230 char *p
= not ? brk
+ 1 : brk
;
232 if (flg
& REG_ICASE
&& c
< 128 && isupper(c
))
234 while (*p
&& (p
== p0
|| *p
!= ']')) {
235 if (p
[0] == '[' && p
[1] == ':') {
236 for (i
= 0; i
< LEN(brk_classes
); i
++) {
237 char *cc
= brk_classes
[i
][0];
238 char *cp
= brk_classes
[i
][1];
239 if (!strncmp(cc
, p
+ 1, strlen(cc
)))
240 if (!brk_match(cp
, c
, flg
))
249 if (p
[0] == '-' && p
[1] && p
[1] != ']') {
254 if (flg
& REG_ICASE
&& beg
< 128 && isupper(beg
))
256 if (flg
& REG_ICASE
&& end
< 128 && isupper(end
))
258 if (c
>= beg
&& c
<= end
)
264 static int ratom_match(struct ratom
*ra
, struct rstate
*rs
)
266 if (ra
->ra
== RA_CHR
) {
267 int c1
= uc_dec(ra
->s
);
268 int c2
= uc_dec(rs
->s
);
269 if (rs
->flg
& REG_ICASE
&& c1
< 128 && isupper(c1
))
271 if (rs
->flg
& REG_ICASE
&& c2
< 128 && isupper(c2
))
275 rs
->s
+= uc_len(ra
->s
);
278 if (ra
->ra
== RA_ANY
) {
281 rs
->s
+= uc_len(rs
->s
);
284 if (ra
->ra
== RA_BRK
) {
285 int c
= uc_dec(rs
->s
);
288 rs
->s
+= uc_len(rs
->s
);
289 return brk_match(ra
->s
+ 1, c
, rs
->flg
);
291 if (ra
->ra
== RA_BEG
&& !(rs
->flg
& REG_NOTBOL
))
292 return !(rs
->s
== rs
->o
|| rs
->s
[-1] == '\n');
293 if (ra
->ra
== RA_END
&& !(rs
->flg
& REG_NOTEOL
))
294 return rs
->s
[0] != '\0' && rs
->s
[0] != '\n';
295 if (ra
->ra
== RA_WBEG
)
296 return !((rs
->s
== rs
->o
|| !isword(uc_beg(rs
->o
, rs
->s
- 1))) &&
298 if (ra
->ra
== RA_WEND
)
299 return !(rs
->s
!= rs
->o
&& isword(uc_beg(rs
->o
, rs
->s
- 1)) &&
300 (!rs
->s
[0] || !isword(rs
->s
)));
304 static struct rnode
*rnode_parse(char **pat
);
306 static struct rnode
*rnode_grp(char **pat
)
309 if ((*pat
)[0] != '(')
312 rnode
= rnode_parse(pat
);
315 if ((*pat
)[0] != ')') {
320 return rnode_make(RN_GRP
, rnode
, NULL
);
323 static struct rnode
*rnode_atom(char **pat
)
328 if ((*pat
)[0] == '|' || (*pat
)[0] == ')')
330 if ((*pat
)[0] == '(') {
331 rnode
= rnode_grp(pat
);
333 rnode
= rnode_make(RN_ATOM
, NULL
, NULL
);
334 ratom_read(&rnode
->ra
, pat
);
338 if ((*pat
)[0] == '*' || (*pat
)[0] == '?') {
340 rnode
->maxcnt
= (*pat
)[0] == '*' ? -1 : 1;
343 if ((*pat
)[0] == '+') {
345 rnode
->maxcnt
= NREPS
;
348 if ((*pat
)[0] == '{') {
352 while (isdigit((unsigned char) **pat
))
353 rnode
->mincnt
= rnode
->mincnt
* 10 + *(*pat
)++ - '0';
356 if ((*pat
)[0] == '}')
357 rnode
->maxcnt
= NREPS
;
358 while (isdigit((unsigned char) **pat
))
359 rnode
->maxcnt
= rnode
->maxcnt
* 10 + *(*pat
)++ - '0';
361 rnode
->maxcnt
= rnode
->mincnt
;
364 if (rnode
->mincnt
> NREPS
|| rnode
->maxcnt
> NREPS
) {
372 static struct rnode
*rnode_seq(char **pat
)
374 struct rnode
*c1
= rnode_atom(pat
);
379 return c2
? rnode_make(RN_CAT
, c1
, c2
) : c1
;
382 static struct rnode
*rnode_parse(char **pat
)
384 struct rnode
*c1
= rnode_seq(pat
);
386 if ((*pat
)[0] != '|')
389 c2
= rnode_parse(pat
);
390 return c2
? rnode_make(RN_ALT
, c1
, c2
) : c1
;
393 static int rnode_count(struct rnode
*rnode
)
398 if (rnode
->rn
== RN_CAT
)
399 n
= rnode_count(rnode
->c1
) + rnode_count(rnode
->c2
);
400 if (rnode
->rn
== RN_ALT
)
401 n
= rnode_count(rnode
->c1
) + rnode_count(rnode
->c2
) + 2;
402 if (rnode
->rn
== RN_GRP
)
403 n
= rnode_count(rnode
->c1
) + 2;
404 if (rnode
->mincnt
== 0 && rnode
->maxcnt
== 0)
406 if (rnode
->mincnt
== 1 && rnode
->maxcnt
== 1)
408 if (rnode
->maxcnt
< 0) {
409 n
= (rnode
->mincnt
+ 1) * n
+ 1;
411 n
= (rnode
->mincnt
+ rnode
->maxcnt
) * n
+
412 rnode
->maxcnt
- rnode
->mincnt
;
419 static int re_insert(struct regex
*p
, int ri
)
421 p
->p
[p
->n
++].ri
= ri
;
425 static void rnode_emit(struct rnode
*n
, struct regex
*p
);
427 static void rnode_emitnorep(struct rnode
*n
, struct regex
*p
)
429 int fork
, done
, mark
;
430 if (n
->rn
== RN_ALT
) {
431 fork
= re_insert(p
, RI_FORK
);
432 p
->p
[fork
].a1
= p
->n
;
433 rnode_emit(n
->c1
, p
);
434 done
= re_insert(p
, RI_JUMP
);
435 p
->p
[fork
].a2
= p
->n
;
436 rnode_emit(n
->c2
, p
);
437 p
->p
[done
].a1
= p
->n
;
439 if (n
->rn
== RN_CAT
) {
440 rnode_emit(n
->c1
, p
);
441 rnode_emit(n
->c2
, p
);
443 if (n
->rn
== RN_GRP
) {
444 int grp
= p
->grpcnt
++ + 1;
445 mark
= re_insert(p
, RI_MARK
);
446 p
->p
[mark
].mark
= 2 * grp
;
447 rnode_emit(n
->c1
, p
);
448 mark
= re_insert(p
, RI_MARK
);
449 p
->p
[mark
].mark
= 2 * grp
+ 1;
451 if (n
->rn
== RN_ATOM
) {
452 int atom
= re_insert(p
, RI_ATOM
);
453 ratom_copy(&p
->p
[atom
].ra
, &n
->ra
);
457 static void rnode_emit(struct rnode
*n
, struct regex
*p
)
465 if (n
->mincnt
== 0 && n
->maxcnt
== 0)
467 if (n
->mincnt
== 1 && n
->maxcnt
== 1) {
468 rnode_emitnorep(n
, p
);
471 if (n
->mincnt
== 0) {
472 int fork
= re_insert(p
, RI_FORK
);
473 p
->p
[fork
].a1
= p
->n
;
474 jmpend
[jmpend_cnt
++] = fork
;
476 for (i
= 0; i
< MAX(1, n
->mincnt
); i
++) {
478 rnode_emitnorep(n
, p
);
482 fork
= re_insert(p
, RI_FORK
);
483 p
->p
[fork
].a1
= last
;
484 p
->p
[fork
].a2
= p
->n
;
486 for (i
= MAX(1, n
->mincnt
); i
< n
->maxcnt
; i
++) {
487 int fork
= re_insert(p
, RI_FORK
);
488 p
->p
[fork
].a1
= p
->n
;
489 jmpend
[jmpend_cnt
++] = fork
;
490 rnode_emitnorep(n
, p
);
492 for (i
= 0; i
< jmpend_cnt
; i
++)
493 p
->p
[jmpend
[i
]].a2
= p
->n
;
496 int regcomp(regex_t
*preg
, char *pat
, int flg
)
498 struct rnode
*rnode
= rnode_parse(&pat
);
500 int n
= rnode_count(rnode
) + 3;
504 re
= malloc(sizeof(*re
));
505 memset(re
, 0, sizeof(*re
));
506 re
->p
= malloc(n
* sizeof(re
->p
[0]));
507 memset(re
->p
, 0, n
* sizeof(re
->p
[0]));
508 mark
= re_insert(re
, RI_MARK
);
509 re
->p
[mark
].mark
= 0;
510 rnode_emit(rnode
, re
);
511 mark
= re_insert(re
, RI_MARK
);
512 re
->p
[mark
].mark
= 1;
513 mark
= re_insert(re
, RI_MATCH
);
520 void regfree(regex_t
*preg
)
522 struct regex
*re
= *preg
;
524 for (i
= 0; i
< re
->n
; i
++)
525 if (re
->p
[i
].ri
== RI_ATOM
)
531 static int re_rec(struct regex
*re
, struct rstate
*rs
)
533 struct rinst
*ri
= &re
->p
[rs
->pc
];
534 if (ri
->ri
== RI_ATOM
) {
535 if (ratom_match(&ri
->ra
, rs
))
538 return re_rec(re
, rs
);
540 if (ri
->ri
== RI_MARK
) {
541 if (ri
->mark
< NGRPS
)
542 rs
->mark
[ri
->mark
] = rs
->s
- rs
->o
;
544 return re_rec(re
, rs
);
546 if (ri
->ri
== RI_JUMP
) {
548 return re_rec(re
, rs
);
550 if (ri
->ri
== RI_FORK
) {
551 struct rstate base
= *rs
;
557 return re_rec(re
, rs
);
559 if (ri
->ri
== RI_MATCH
)
564 static int re_recmatch(struct regex
*re
, struct rstate
*rs
, int nsub
, regmatch_t
*psub
)
568 for (i
= 0; i
< LEN(rs
->mark
); i
++)
570 if (!re_rec(re
, rs
)) {
571 for (i
= 0; i
< nsub
; i
++) {
572 psub
[i
].rm_so
= i
* 2 < LEN(rs
->mark
) ? rs
->mark
[i
* 2] : -1;
573 psub
[i
].rm_eo
= i
* 2 < LEN(rs
->mark
) ? rs
->mark
[i
* 2 + 1] : -1;
580 int regexec(regex_t
*preg
, char *s
, int nsub
, regmatch_t psub
[], int flg
)
582 struct regex
*re
= *preg
;
584 memset(&rs
, 0, sizeof(rs
));
585 rs
.flg
= re
->flg
| flg
;
590 if (!re_recmatch(re
, &rs
, flg
& REG_NOSUB
? 0 : nsub
, psub
))
596 int regerror(int errcode
, regex_t
*preg
, char *errbuf
, int errbuf_size
)