1/*
2** $Id: lstrlib.c,v 1.254.1.1 2017/04/19 17:29:57 roberto Exp $
3** Standard library for string operations and pattern-matching
4** See Copyright Notice in lua.h
5*/
6
7#define lstrlib_c
8#define LUA_LIB
9
10#include "lprefix.h"
11
12
13#include <ctype.h>
14#include <float.h>
15#include <limits.h>
16#include <locale.h>
17#include <stddef.h>
18#include <stdio.h>
19#include <stdlib.h>
20#include <string.h>
21
22#include "lua.h"
23
24#include "lauxlib.h"
25#include "lualib.h"
26
27
28/*
29** maximum number of captures that a pattern can do during
30** pattern-matching. This limit is arbitrary, but must fit in
31** an unsigned char.
32*/
33#if !defined(LUA_MAXCAPTURES)
34#define LUA_MAXCAPTURES 32
35#endif
36
37
38/* macro to 'unsign' a character */
39#define uchar(c) ((unsigned char)(c))
40
41
42/*
43** Some sizes are better limited to fit in 'int', but must also fit in
44** 'size_t'. (We assume that 'lua_Integer' cannot be smaller than 'int'.)
45*/
46#define MAX_SIZET ((size_t)(~(size_t)0))
47
48#define MAXSIZE \
49 (sizeof(size_t) < sizeof(int) ? MAX_SIZET : (size_t)(INT_MAX))
50
51
52
53
54static int str_len (lua_State *L) {
55 size_t l;
56 luaL_checklstring(L, 1, &l);
57 lua_pushinteger(L, (lua_Integer)l);
58 return 1;
59}
60
61
62/* translate a relative string position: negative means back from end */
63static lua_Integer posrelat (lua_Integer pos, size_t len) {
64 if (pos >= 0) return pos;
65 else if (0u - (size_t)pos > len) return 0;
66 else return (lua_Integer)len + pos + 1;
67}
68
69
70static int str_sub (lua_State *L) {
71 size_t l;
72 const char *s = luaL_checklstring(L, 1, &l);
73 lua_Integer start = posrelat(luaL_checkinteger(L, 2), l);
74 lua_Integer end = posrelat(luaL_optinteger(L, 3, -1), l);
75 if (start < 1) start = 1;
76 if (end > (lua_Integer)l) end = l;
77 if (start <= end)
78 lua_pushlstring(L, s + start - 1, (size_t)(end - start) + 1);
79 else lua_pushliteral(L, "");
80 return 1;
81}
82
83
84static int str_reverse (lua_State *L) {
85 size_t l, i;
86 luaL_Buffer b;
87 const char *s = luaL_checklstring(L, 1, &l);
88 char *p = luaL_buffinitsize(L, &b, l);
89 for (i = 0; i < l; i++)
90 p[i] = s[l - i - 1];
91 luaL_pushresultsize(&b, l);
92 return 1;
93}
94
95
96static int str_lower (lua_State *L) {
97 size_t l;
98 size_t i;
99 luaL_Buffer b;
100 const char *s = luaL_checklstring(L, 1, &l);
101 char *p = luaL_buffinitsize(L, &b, l);
102 for (i=0; i<l; i++)
103 p[i] = tolower(uchar(s[i]));
104 luaL_pushresultsize(&b, l);
105 return 1;
106}
107
108
109static int str_upper (lua_State *L) {
110 size_t l;
111 size_t i;
112 luaL_Buffer b;
113 const char *s = luaL_checklstring(L, 1, &l);
114 char *p = luaL_buffinitsize(L, &b, l);
115 for (i=0; i<l; i++)
116 p[i] = toupper(uchar(s[i]));
117 luaL_pushresultsize(&b, l);
118 return 1;
119}
120
121
122static int str_rep (lua_State *L) {
123 size_t l, lsep;
124 const char *s = luaL_checklstring(L, 1, &l);
125 lua_Integer n = luaL_checkinteger(L, 2);
126 const char *sep = luaL_optlstring(L, 3, "", &lsep);
127 if (n <= 0) lua_pushliteral(L, "");
128 else if (l + lsep < l || l + lsep > MAXSIZE / n) /* may overflow? */
129 return luaL_error(L, "resulting string too large");
130 else {
131 size_t totallen = (size_t)n * l + (size_t)(n - 1) * lsep;
132 luaL_Buffer b;
133 char *p = luaL_buffinitsize(L, &b, totallen);
134 while (n-- > 1) { /* first n-1 copies (followed by separator) */
135 memcpy(p, s, l * sizeof(char)); p += l;
136 if (lsep > 0) { /* empty 'memcpy' is not that cheap */
137 memcpy(p, sep, lsep * sizeof(char));
138 p += lsep;
139 }
140 }
141 memcpy(p, s, l * sizeof(char)); /* last copy (not followed by separator) */
142 luaL_pushresultsize(&b, totallen);
143 }
144 return 1;
145}
146
147
148static int str_byte (lua_State *L) {
149 size_t l;
150 const char *s = luaL_checklstring(L, 1, &l);
151 lua_Integer posi = posrelat(luaL_optinteger(L, 2, 1), l);
152 lua_Integer pose = posrelat(luaL_optinteger(L, 3, posi), l);
153 int n, i;
154 if (posi < 1) posi = 1;
155 if (pose > (lua_Integer)l) pose = l;
156 if (posi > pose) return 0; /* empty interval; return no values */
157 if (pose - posi >= INT_MAX) /* arithmetic overflow? */
158 return luaL_error(L, "string slice too long");
159 n = (int)(pose - posi) + 1;
160 luaL_checkstack(L, n, "string slice too long");
161 for (i=0; i<n; i++)
162 lua_pushinteger(L, uchar(s[posi+i-1]));
163 return n;
164}
165
166
167static int str_char (lua_State *L) {
168 int n = lua_gettop(L); /* number of arguments */
169 int i;
170 luaL_Buffer b;
171 char *p = luaL_buffinitsize(L, &b, n);
172 for (i=1; i<=n; i++) {
173 lua_Integer c = luaL_checkinteger(L, i);
174 luaL_argcheck(L, uchar(c) == c, i, "value out of range");
175 p[i - 1] = uchar(c);
176 }
177 luaL_pushresultsize(&b, n);
178 return 1;
179}
180
181
182static int writer (lua_State *L, const void *b, size_t size, void *B) {
183 (void)L;
184 luaL_addlstring((luaL_Buffer *) B, (const char *)b, size);
185 return 0;
186}
187
188
189static int str_dump (lua_State *L) {
190 luaL_Buffer b;
191 int strip = lua_toboolean(L, 2);
192 luaL_checktype(L, 1, LUA_TFUNCTION);
193 lua_settop(L, 1);
194 luaL_buffinit(L,&b);
195 if (lua_dump(L, writer, &b, strip) != 0)
196 return luaL_error(L, "unable to dump given function");
197 luaL_pushresult(&b);
198 return 1;
199}
200
201
202
203/*
204** {======================================================
205** PATTERN MATCHING
206** =======================================================
207*/
208
209
210#define CAP_UNFINISHED (-1)
211#define CAP_POSITION (-2)
212
213
214typedef struct MatchState {
215 const char *src_init; /* init of source string */
216 const char *src_end; /* end ('\0') of source string */
217 const char *p_end; /* end ('\0') of pattern */
218 lua_State *L;
219 int matchdepth; /* control for recursive depth (to avoid C stack overflow) */
220 unsigned char level; /* total number of captures (finished or unfinished) */
221 struct {
222 const char *init;
223 ptrdiff_t len;
224 } capture[LUA_MAXCAPTURES];
225} MatchState;
226
227
228/* recursive function */
229static const char *match (MatchState *ms, const char *s, const char *p);
230
231
232/* maximum recursion depth for 'match' */
233#if !defined(MAXCCALLS)
234#define MAXCCALLS 200
235#endif
236
237
238#define L_ESC '%'
239#define SPECIALS "^$*+?.([%-"
240
241
242static int check_capture (MatchState *ms, int l) {
243 l -= '1';
244 if (l < 0 || l >= ms->level || ms->capture[l].len == CAP_UNFINISHED)
245 return luaL_error(ms->L, "invalid capture index %%%d", l + 1);
246 return l;
247}
248
249
250static int capture_to_close (MatchState *ms) {
251 int level = ms->level;
252 for (level--; level>=0; level--)
253 if (ms->capture[level].len == CAP_UNFINISHED) return level;
254 return luaL_error(ms->L, "invalid pattern capture");
255}
256
257
258static const char *classend (MatchState *ms, const char *p) {
259 switch (*p++) {
260 case L_ESC: {
261 if (p == ms->p_end)
262 luaL_error(ms->L, "malformed pattern (ends with '%%')");
263 return p+1;
264 }
265 case '[': {
266 if (*p == '^') p++;
267 do { /* look for a ']' */
268 if (p == ms->p_end)
269 luaL_error(ms->L, "malformed pattern (missing ']')");
270 if (*(p++) == L_ESC && p < ms->p_end)
271 p++; /* skip escapes (e.g. '%]') */
272 } while (*p != ']');
273 return p+1;
274 }
275 default: {
276 return p;
277 }
278 }
279}
280
281
282static int match_class (int c, int cl) {
283 int res;
284 switch (tolower(cl)) {
285 case 'a' : res = isalpha(c); break;
286 case 'c' : res = iscntrl(c); break;
287 case 'd' : res = isdigit(c); break;
288 case 'g' : res = isgraph(c); break;
289 case 'l' : res = islower(c); break;
290 case 'p' : res = ispunct(c); break;
291 case 's' : res = isspace(c); break;
292 case 'u' : res = isupper(c); break;
293 case 'w' : res = isalnum(c); break;
294 case 'x' : res = isxdigit(c); break;
295 case 'z' : res = (c == 0); break; /* deprecated option */
296 default: return (cl == c);
297 }
298 return (islower(cl) ? res : !res);
299}
300
301
302static int matchbracketclass (int c, const char *p, const char *ec) {
303 int sig = 1;
304 if (*(p+1) == '^') {
305 sig = 0;
306 p++; /* skip the '^' */
307 }
308 while (++p < ec) {
309 if (*p == L_ESC) {
310 p++;
311 if (match_class(c, uchar(*p)))
312 return sig;
313 }
314 else if ((*(p+1) == '-') && (p+2 < ec)) {
315 p+=2;
316 if (uchar(*(p-2)) <= c && c <= uchar(*p))
317 return sig;
318 }
319 else if (uchar(*p) == c) return sig;
320 }
321 return !sig;
322}
323
324
325static int singlematch (MatchState *ms, const char *s, const char *p,
326 const char *ep) {
327 if (s >= ms->src_end)
328 return 0;
329 else {
330 int c = uchar(*s);
331 switch (*p) {
332 case '.': return 1; /* matches any char */
333 case L_ESC: return match_class(c, uchar(*(p+1)));
334 case '[': return matchbracketclass(c, p, ep-1);
335 default: return (uchar(*p) == c);
336 }
337 }
338}
339
340
341static const char *matchbalance (MatchState *ms, const char *s,
342 const char *p) {
343 if (p >= ms->p_end - 1)
344 luaL_error(ms->L, "malformed pattern (missing arguments to '%%b')");
345 if (*s != *p) return NULL;
346 else {
347 int b = *p;
348 int e = *(p+1);
349 int cont = 1;
350 while (++s < ms->src_end) {
351 if (*s == e) {
352 if (--cont == 0) return s+1;
353 }
354 else if (*s == b) cont++;
355 }
356 }
357 return NULL; /* string ends out of balance */
358}
359
360
361static const char *max_expand (MatchState *ms, const char *s,
362 const char *p, const char *ep) {
363 ptrdiff_t i = 0; /* counts maximum expand for item */
364 while (singlematch(ms, s + i, p, ep))
365 i++;
366 /* keeps trying to match with the maximum repetitions */
367 while (i>=0) {
368 const char *res = match(ms, (s+i), ep+1);
369 if (res) return res;
370 i--; /* else didn't match; reduce 1 repetition to try again */
371 }
372 return NULL;
373}
374
375
376static const char *min_expand (MatchState *ms, const char *s,
377 const char *p, const char *ep) {
378 for (;;) {
379 const char *res = match(ms, s, ep+1);
380 if (res != NULL)
381 return res;
382 else if (singlematch(ms, s, p, ep))
383 s++; /* try with one more repetition */
384 else return NULL;
385 }
386}
387
388
389static const char *start_capture (MatchState *ms, const char *s,
390 const char *p, int what) {
391 const char *res;
392 int level = ms->level;
393 if (level >= LUA_MAXCAPTURES) luaL_error(ms->L, "too many captures");
394 ms->capture[level].init = s;
395 ms->capture[level].len = what;
396 ms->level = level+1;
397 if ((res=match(ms, s, p)) == NULL) /* match failed? */
398 ms->level--; /* undo capture */
399 return res;
400}
401
402
403static const char *end_capture (MatchState *ms, const char *s,
404 const char *p) {
405 int l = capture_to_close(ms);
406 const char *res;
407 ms->capture[l].len = s - ms->capture[l].init; /* close capture */
408 if ((res = match(ms, s, p)) == NULL) /* match failed? */
409 ms->capture[l].len = CAP_UNFINISHED; /* undo capture */
410 return res;
411}
412
413
414static const char *match_capture (MatchState *ms, const char *s, int l) {
415 size_t len;
416 l = check_capture(ms, l);
417 len = ms->capture[l].len;
418 if ((size_t)(ms->src_end-s) >= len &&
419 memcmp(ms->capture[l].init, s, len) == 0)
420 return s+len;
421 else return NULL;
422}
423
424
425static const char *match (MatchState *ms, const char *s, const char *p) {
426 if (ms->matchdepth-- == 0)
427 luaL_error(ms->L, "pattern too complex");
428 init: /* using goto's to optimize tail recursion */
429 if (p != ms->p_end) { /* end of pattern? */
430 switch (*p) {
431 case '(': { /* start capture */
432 if (*(p + 1) == ')') /* position capture? */
433 s = start_capture(ms, s, p + 2, CAP_POSITION);
434 else
435 s = start_capture(ms, s, p + 1, CAP_UNFINISHED);
436 break;
437 }
438 case ')': { /* end capture */
439 s = end_capture(ms, s, p + 1);
440 break;
441 }
442 case '$': {
443 if ((p + 1) != ms->p_end) /* is the '$' the last char in pattern? */
444 goto dflt; /* no; go to default */
445 s = (s == ms->src_end) ? s : NULL; /* check end of string */
446 break;
447 }
448 case L_ESC: { /* escaped sequences not in the format class[*+?-]? */
449 switch (*(p + 1)) {
450 case 'b': { /* balanced string? */
451 s = matchbalance(ms, s, p + 2);
452 if (s != NULL) {
453 p += 4; goto init; /* return match(ms, s, p + 4); */
454 } /* else fail (s == NULL) */
455 break;
456 }
457 case 'f': { /* frontier? */
458 const char *ep; char previous;
459 p += 2;
460 if (*p != '[')
461 luaL_error(ms->L, "missing '[' after '%%f' in pattern");
462 ep = classend(ms, p); /* points to what is next */
463 previous = (s == ms->src_init) ? '\0' : *(s - 1);
464 if (!matchbracketclass(uchar(previous), p, ep - 1) &&
465 matchbracketclass(uchar(*s), p, ep - 1)) {
466 p = ep; goto init; /* return match(ms, s, ep); */
467 }
468 s = NULL; /* match failed */
469 break;
470 }
471 case '0': case '1': case '2': case '3':
472 case '4': case '5': case '6': case '7':
473 case '8': case '9': { /* capture results (%0-%9)? */
474 s = match_capture(ms, s, uchar(*(p + 1)));
475 if (s != NULL) {
476 p += 2; goto init; /* return match(ms, s, p + 2) */
477 }
478 break;
479 }
480 default: goto dflt;
481 }
482 break;
483 }
484 default: dflt: { /* pattern class plus optional suffix */
485 const char *ep = classend(ms, p); /* points to optional suffix */
486 /* does not match at least once? */
487 if (!singlematch(ms, s, p, ep)) {
488 if (*ep == '*' || *ep == '?' || *ep == '-') { /* accept empty? */
489 p = ep + 1; goto init; /* return match(ms, s, ep + 1); */
490 }
491 else /* '+' or no suffix */
492 s = NULL; /* fail */
493 }
494 else { /* matched once */
495 switch (*ep) { /* handle optional suffix */
496 case '?': { /* optional */
497 const char *res;
498 if ((res = match(ms, s + 1, ep + 1)) != NULL)
499 s = res;
500 else {
501 p = ep + 1; goto init; /* else return match(ms, s, ep + 1); */
502 }
503 break;
504 }
505 case '+': /* 1 or more repetitions */
506 s++; /* 1 match already done */
507 /* FALLTHROUGH */
508 case '*': /* 0 or more repetitions */
509 s = max_expand(ms, s, p, ep);
510 break;
511 case '-': /* 0 or more repetitions (minimum) */
512 s = min_expand(ms, s, p, ep);
513 break;
514 default: /* no suffix */
515 s++; p = ep; goto init; /* return match(ms, s + 1, ep); */
516 }
517 }
518 break;
519 }
520 }
521 }
522 ms->matchdepth++;
523 return s;
524}
525
526
527
528static const char *lmemfind (const char *s1, size_t l1,
529 const char *s2, size_t l2) {
530 if (l2 == 0) return s1; /* empty strings are everywhere */
531 else if (l2 > l1) return NULL; /* avoids a negative 'l1' */
532 else {
533 const char *init; /* to search for a '*s2' inside 's1' */
534 l2--; /* 1st char will be checked by 'memchr' */
535 l1 = l1-l2; /* 's2' cannot be found after that */
536 while (l1 > 0 && (init = (const char *)memchr(s1, *s2, l1)) != NULL) {
537 init++; /* 1st char is already checked */
538 if (memcmp(init, s2+1, l2) == 0)
539 return init-1;
540 else { /* correct 'l1' and 's1' to try again */
541 l1 -= init-s1;
542 s1 = init;
543 }
544 }
545 return NULL; /* not found */
546 }
547}
548
549
550static void push_onecapture (MatchState *ms, int i, const char *s,
551 const char *e) {
552 if (i >= ms->level) {
553 if (i == 0) /* ms->level == 0, too */
554 lua_pushlstring(ms->L, s, e - s); /* add whole match */
555 else
556 luaL_error(ms->L, "invalid capture index %%%d", i + 1);
557 }
558 else {
559 ptrdiff_t l = ms->capture[i].len;
560 if (l == CAP_UNFINISHED) luaL_error(ms->L, "unfinished capture");
561 if (l == CAP_POSITION)
562 lua_pushinteger(ms->L, (ms->capture[i].init - ms->src_init) + 1);
563 else
564 lua_pushlstring(ms->L, ms->capture[i].init, l);
565 }
566}
567
568
569static int push_captures (MatchState *ms, const char *s, const char *e) {
570 int i;
571 int nlevels = (ms->level == 0 && s) ? 1 : ms->level;
572 luaL_checkstack(ms->L, nlevels, "too many captures");
573 for (i = 0; i < nlevels; i++)
574 push_onecapture(ms, i, s, e);
575 return nlevels; /* number of strings pushed */
576}
577
578
579/* check whether pattern has no special characters */
580static int nospecials (const char *p, size_t l) {
581 size_t upto = 0;
582 do {
583 if (strpbrk(p + upto, SPECIALS))
584 return 0; /* pattern has a special character */
585 upto += strlen(p + upto) + 1; /* may have more after \0 */
586 } while (upto <= l);
587 return 1; /* no special chars found */
588}
589
590
591static void prepstate (MatchState *ms, lua_State *L,
592 const char *s, size_t ls, const char *p, size_t lp) {
593 ms->L = L;
594 ms->matchdepth = MAXCCALLS;
595 ms->src_init = s;
596 ms->src_end = s + ls;
597 ms->p_end = p + lp;
598}
599
600
601static void reprepstate (MatchState *ms) {
602 ms->level = 0;
603 lua_assert(ms->matchdepth == MAXCCALLS);
604}
605
606
607static int str_find_aux (lua_State *L, int find) {
608 size_t ls, lp;
609 const char *s = luaL_checklstring(L, 1, &ls);
610 const char *p = luaL_checklstring(L, 2, &lp);
611 lua_Integer init = posrelat(luaL_optinteger(L, 3, 1), ls);
612 if (init < 1) init = 1;
613 else if (init > (lua_Integer)ls + 1) { /* start after string's end? */
614 lua_pushnil(L); /* cannot find anything */
615 return 1;
616 }
617 /* explicit request or no special characters? */
618 if (find && (lua_toboolean(L, 4) || nospecials(p, lp))) {
619 /* do a plain search */
620 const char *s2 = lmemfind(s + init - 1, ls - (size_t)init + 1, p, lp);
621 if (s2) {
622 lua_pushinteger(L, (s2 - s) + 1);
623 lua_pushinteger(L, (s2 - s) + lp);
624 return 2;
625 }
626 }
627 else {
628 MatchState ms;
629 const char *s1 = s + init - 1;
630 int anchor = (*p == '^');
631 if (anchor) {
632 p++; lp--; /* skip anchor character */
633 }
634 prepstate(&ms, L, s, ls, p, lp);
635 do {
636 const char *res;
637 reprepstate(&ms);
638 if ((res=match(&ms, s1, p)) != NULL) {
639 if (find) {
640 lua_pushinteger(L, (s1 - s) + 1); /* start */
641 lua_pushinteger(L, res - s); /* end */
642 return push_captures(&ms, NULL, 0) + 2;
643 }
644 else
645 return push_captures(&ms, s1, res);
646 }
647 } while (s1++ < ms.src_end && !anchor);
648 }
649 lua_pushnil(L); /* not found */
650 return 1;
651}
652
653
654static int str_find (lua_State *L) {
655 return str_find_aux(L, 1);
656}
657
658
659static int str_match (lua_State *L) {
660 return str_find_aux(L, 0);
661}
662
663
664/* state for 'gmatch' */
665typedef struct GMatchState {
666 const char *src; /* current position */
667 const char *p; /* pattern */
668 const char *lastmatch; /* end of last match */
669 MatchState ms; /* match state */
670} GMatchState;
671
672
673static int gmatch_aux (lua_State *L) {
674 GMatchState *gm = (GMatchState *)lua_touserdata(L, lua_upvalueindex(3));
675 const char *src;
676 gm->ms.L = L;
677 for (src = gm->src; src <= gm->ms.src_end; src++) {
678 const char *e;
679 reprepstate(&gm->ms);
680 if ((e = match(&gm->ms, src, gm->p)) != NULL && e != gm->lastmatch) {
681 gm->src = gm->lastmatch = e;
682 return push_captures(&gm->ms, src, e);
683 }
684 }
685 return 0; /* not found */
686}
687
688
689static int gmatch (lua_State *L) {
690 size_t ls, lp;
691 const char *s = luaL_checklstring(L, 1, &ls);
692 const char *p = luaL_checklstring(L, 2, &lp);
693 GMatchState *gm;
694 lua_settop(L, 2); /* keep them on closure to avoid being collected */
695 gm = (GMatchState *)lua_newuserdata(L, sizeof(GMatchState));
696 prepstate(&gm->ms, L, s, ls, p, lp);
697 gm->src = s; gm->p = p; gm->lastmatch = NULL;
698 lua_pushcclosure(L, gmatch_aux, 3);
699 return 1;
700}
701
702
703static void add_s (MatchState *ms, luaL_Buffer *b, const char *s,
704 const char *e) {
705 size_t l, i;
706 lua_State *L = ms->L;
707 const char *news = lua_tolstring(L, 3, &l);
708 for (i = 0; i < l; i++) {
709 if (news[i] != L_ESC)
710 luaL_addchar(b, news[i]);
711 else {
712 i++; /* skip ESC */
713 if (!isdigit(uchar(news[i]))) {
714 if (news[i] != L_ESC)
715 luaL_error(L, "invalid use of '%c' in replacement string", L_ESC);
716 luaL_addchar(b, news[i]);
717 }
718 else if (news[i] == '0')
719 luaL_addlstring(b, s, e - s);
720 else {
721 push_onecapture(ms, news[i] - '1', s, e);
722 luaL_tolstring(L, -1, NULL); /* if number, convert it to string */
723 lua_remove(L, -2); /* remove original value */
724 luaL_addvalue(b); /* add capture to accumulated result */
725 }
726 }
727 }
728}
729
730
731static void add_value (MatchState *ms, luaL_Buffer *b, const char *s,
732 const char *e, int tr) {
733 lua_State *L = ms->L;
734 switch (tr) {
735 case LUA_TFUNCTION: {
736 int n;
737 lua_pushvalue(L, 3);
738 n = push_captures(ms, s, e);
739 lua_call(L, n, 1);
740 break;
741 }
742 case LUA_TTABLE: {
743 push_onecapture(ms, 0, s, e);
744 lua_gettable(L, 3);
745 break;
746 }
747 default: { /* LUA_TNUMBER or LUA_TSTRING */
748 add_s(ms, b, s, e);
749 return;
750 }
751 }
752 if (!lua_toboolean(L, -1)) { /* nil or false? */
753 lua_pop(L, 1);
754 lua_pushlstring(L, s, e - s); /* keep original text */
755 }
756 else if (!lua_isstring(L, -1))
757 luaL_error(L, "invalid replacement value (a %s)", luaL_typename(L, -1));
758 luaL_addvalue(b); /* add result to accumulator */
759}
760
761
762static int str_gsub (lua_State *L) {
763 size_t srcl, lp;
764 const char *src = luaL_checklstring(L, 1, &srcl); /* subject */
765 const char *p = luaL_checklstring(L, 2, &lp); /* pattern */
766 const char *lastmatch = NULL; /* end of last match */
767 int tr = lua_type(L, 3); /* replacement type */
768 lua_Integer max_s = luaL_optinteger(L, 4, srcl + 1); /* max replacements */
769 int anchor = (*p == '^');
770 lua_Integer n = 0; /* replacement count */
771 MatchState ms;
772 luaL_Buffer b;
773 luaL_argcheck(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||
774 tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3,
775 "string/function/table expected");
776 luaL_buffinit(L, &b);
777 if (anchor) {
778 p++; lp--; /* skip anchor character */
779 }
780 prepstate(&ms, L, src, srcl, p, lp);
781 while (n < max_s) {
782 const char *e;
783 reprepstate(&ms); /* (re)prepare state for new match */
784 if ((e = match(&ms, src, p)) != NULL && e != lastmatch) { /* match? */
785 n++;
786 add_value(&ms, &b, src, e, tr); /* add replacement to buffer */
787 src = lastmatch = e;
788 }
789 else if (src < ms.src_end) /* otherwise, skip one character */
790 luaL_addchar(&b, *src++);
791 else break; /* end of subject */
792 if (anchor) break;
793 }
794 luaL_addlstring(&b, src, ms.src_end-src);
795 luaL_pushresult(&b);
796 lua_pushinteger(L, n); /* number of substitutions */
797 return 2;
798}
799
800/* }====================================================== */
801
802
803
804/*
805** {======================================================
806** STRING FORMAT
807** =======================================================
808*/
809
810#if !defined(lua_number2strx) /* { */
811
812/*
813** Hexadecimal floating-point formatter
814*/
815
816#include <math.h>
817
818#define SIZELENMOD (sizeof(LUA_NUMBER_FRMLEN)/sizeof(char))
819
820
821/*
822** Number of bits that goes into the first digit. It can be any value
823** between 1 and 4; the following definition tries to align the number
824** to nibble boundaries by making what is left after that first digit a
825** multiple of 4.
826*/
827#define L_NBFD ((l_mathlim(MANT_DIG) - 1)%4 + 1)
828
829
830/*
831** Add integer part of 'x' to buffer and return new 'x'
832*/
833static lua_Number adddigit (char *buff, int n, lua_Number x) {
834 lua_Number dd = l_mathop(floor)(x); /* get integer part from 'x' */
835 int d = (int)dd;
836 buff[n] = (d < 10 ? d + '0' : d - 10 + 'a'); /* add to buffer */
837 return x - dd; /* return what is left */
838}
839
840
841static int num2straux (char *buff, int sz, lua_Number x) {
842 /* if 'inf' or 'NaN', format it like '%g' */
843 if (x != x || x == (lua_Number)HUGE_VAL || x == -(lua_Number)HUGE_VAL)
844 return l_sprintf(buff, sz, LUA_NUMBER_FMT, (LUAI_UACNUMBER)x);
845 else if (x == 0) { /* can be -0... */
846 /* create "0" or "-0" followed by exponent */
847 return l_sprintf(buff, sz, LUA_NUMBER_FMT "x0p+0", (LUAI_UACNUMBER)x);
848 }
849 else {
850 int e;
851 lua_Number m = l_mathop(frexp)(x, &e); /* 'x' fraction and exponent */
852 int n = 0; /* character count */
853 if (m < 0) { /* is number negative? */
854 buff[n++] = '-'; /* add signal */
855 m = -m; /* make it positive */
856 }
857 buff[n++] = '0'; buff[n++] = 'x'; /* add "0x" */
858 m = adddigit(buff, n++, m * (1 << L_NBFD)); /* add first digit */
859 e -= L_NBFD; /* this digit goes before the radix point */
860 if (m > 0) { /* more digits? */
861 buff[n++] = lua_getlocaledecpoint(); /* add radix point */
862 do { /* add as many digits as needed */
863 m = adddigit(buff, n++, m * 16);
864 } while (m > 0);
865 }
866 n += l_sprintf(buff + n, sz - n, "p%+d", e); /* add exponent */
867 lua_assert(n < sz);
868 return n;
869 }
870}
871
872
873static int lua_number2strx (lua_State *L, char *buff, int sz,
874 const char *fmt, lua_Number x) {
875 int n = num2straux(buff, sz, x);
876 if (fmt[SIZELENMOD] == 'A') {
877 int i;
878 for (i = 0; i < n; i++)
879 buff[i] = toupper(uchar(buff[i]));
880 }
881 else if (fmt[SIZELENMOD] != 'a')
882 return luaL_error(L, "modifiers for format '%%a'/'%%A' not implemented");
883 return n;
884}
885
886#endif /* } */
887
888
889/*
890** Maximum size of each formatted item. This maximum size is produced
891** by format('%.99f', -maxfloat), and is equal to 99 + 3 ('-', '.',
892** and '\0') + number of decimal digits to represent maxfloat (which
893** is maximum exponent + 1). (99+3+1 then rounded to 120 for "extra
894** expenses", such as locale-dependent stuff)
895*/
896#define MAX_ITEM (120 + l_mathlim(MAX_10_EXP))
897
898
899/* valid flags in a format specification */
900#define FLAGS "-+ #0"
901
902/*
903** maximum size of each format specification (such as "%-099.99d")
904*/
905#define MAX_FORMAT 32
906
907
908static void addquoted (luaL_Buffer *b, const char *s, size_t len) {
909 luaL_addchar(b, '"');
910 while (len--) {
911 if (*s == '"' || *s == '\\' || *s == '\n') {
912 luaL_addchar(b, '\\');
913 luaL_addchar(b, *s);
914 }
915 else if (iscntrl(uchar(*s))) {
916 char buff[10];
917 if (!isdigit(uchar(*(s+1))))
918 l_sprintf(buff, sizeof(buff), "\\%d", (int)uchar(*s));
919 else
920 l_sprintf(buff, sizeof(buff), "\\%03d", (int)uchar(*s));
921 luaL_addstring(b, buff);
922 }
923 else
924 luaL_addchar(b, *s);
925 s++;
926 }
927 luaL_addchar(b, '"');
928}
929
930
931/*
932** Ensures the 'buff' string uses a dot as the radix character.
933*/
934static void checkdp (char *buff, int nb) {
935 if (memchr(buff, '.', nb) == NULL) { /* no dot? */
936 char point = lua_getlocaledecpoint(); /* try locale point */
937 char *ppoint = (char *)memchr(buff, point, nb);
938 if (ppoint) *ppoint = '.'; /* change it to a dot */
939 }
940}
941
942
943static void addliteral (lua_State *L, luaL_Buffer *b, int arg) {
944 switch (lua_type(L, arg)) {
945 case LUA_TSTRING: {
946 size_t len;
947 const char *s = lua_tolstring(L, arg, &len);
948 addquoted(b, s, len);
949 break;
950 }
951 case LUA_TNUMBER: {
952 char *buff = luaL_prepbuffsize(b, MAX_ITEM);
953 int nb;
954 if (!lua_isinteger(L, arg)) { /* float? */
955 lua_Number n = lua_tonumber(L, arg); /* write as hexa ('%a') */
956 nb = lua_number2strx(L, buff, MAX_ITEM, "%" LUA_NUMBER_FRMLEN "a", n);
957 checkdp(buff, nb); /* ensure it uses a dot */
958 }
959 else { /* integers */
960 lua_Integer n = lua_tointeger(L, arg);
961 const char *format = (n == LUA_MININTEGER) /* corner case? */
962 ? "0x%" LUA_INTEGER_FRMLEN "x" /* use hexa */
963 : LUA_INTEGER_FMT; /* else use default format */
964 nb = l_sprintf(buff, MAX_ITEM, format, (LUAI_UACINT)n);
965 }
966 luaL_addsize(b, nb);
967 break;
968 }
969 case LUA_TNIL: case LUA_TBOOLEAN: {
970 luaL_tolstring(L, arg, NULL);
971 luaL_addvalue(b);
972 break;
973 }
974 default: {
975 luaL_argerror(L, arg, "value has no literal form");
976 }
977 }
978}
979
980
981static const char *scanformat (lua_State *L, const char *strfrmt, char *form) {
982 const char *p = strfrmt;
983 while (*p != '\0' && strchr(FLAGS, *p) != NULL) p++; /* skip flags */
984 if ((size_t)(p - strfrmt) >= sizeof(FLAGS)/sizeof(char))
985 luaL_error(L, "invalid format (repeated flags)");
986 if (isdigit(uchar(*p))) p++; /* skip width */
987 if (isdigit(uchar(*p))) p++; /* (2 digits at most) */
988 if (*p == '.') {
989 p++;
990 if (isdigit(uchar(*p))) p++; /* skip precision */
991 if (isdigit(uchar(*p))) p++; /* (2 digits at most) */
992 }
993 if (isdigit(uchar(*p)))
994 luaL_error(L, "invalid format (width or precision too long)");
995 *(form++) = '%';
996 memcpy(form, strfrmt, ((p - strfrmt) + 1) * sizeof(char));
997 form += (p - strfrmt) + 1;
998 *form = '\0';
999 return p;
1000}
1001
1002
1003/*
1004** add length modifier into formats
1005*/
1006static void addlenmod (char *form, const char *lenmod) {
1007 size_t l = strlen(form);
1008 size_t lm = strlen(lenmod);
1009 char spec = form[l - 1];
1010 strcpy(form + l - 1, lenmod);
1011 form[l + lm - 1] = spec;
1012 form[l + lm] = '\0';
1013}
1014
1015
1016static int str_format (lua_State *L) {
1017 int top = lua_gettop(L);
1018 int arg = 1;
1019 size_t sfl;
1020 const char *strfrmt = luaL_checklstring(L, arg, &sfl);
1021 const char *strfrmt_end = strfrmt+sfl;
1022 luaL_Buffer b;
1023 luaL_buffinit(L, &b);
1024 while (strfrmt < strfrmt_end) {
1025 if (*strfrmt != L_ESC)
1026 luaL_addchar(&b, *strfrmt++);
1027 else if (*++strfrmt == L_ESC)
1028 luaL_addchar(&b, *strfrmt++); /* %% */
1029 else { /* format item */
1030 char form[MAX_FORMAT]; /* to store the format ('%...') */
1031 char *buff = luaL_prepbuffsize(&b, MAX_ITEM); /* to put formatted item */
1032 int nb = 0; /* number of bytes in added item */
1033 if (++arg > top)
1034 luaL_argerror(L, arg, "no value");
1035 strfrmt = scanformat(L, strfrmt, form);
1036 switch (*strfrmt++) {
1037 case 'c': {
1038 nb = l_sprintf(buff, MAX_ITEM, form, (int)luaL_checkinteger(L, arg));
1039 break;
1040 }
1041 case 'd': case 'i':
1042 case 'o': case 'u': case 'x': case 'X': {
1043 lua_Integer n = luaL_checkinteger(L, arg);
1044 addlenmod(form, LUA_INTEGER_FRMLEN);
1045 nb = l_sprintf(buff, MAX_ITEM, form, (LUAI_UACINT)n);
1046 break;
1047 }
1048 case 'a': case 'A':
1049 addlenmod(form, LUA_NUMBER_FRMLEN);
1050 nb = lua_number2strx(L, buff, MAX_ITEM, form,
1051 luaL_checknumber(L, arg));
1052 break;
1053 case 'e': case 'E': case 'f':
1054 case 'g': case 'G': {
1055 lua_Number n = luaL_checknumber(L, arg);
1056 addlenmod(form, LUA_NUMBER_FRMLEN);
1057 nb = l_sprintf(buff, MAX_ITEM, form, (LUAI_UACNUMBER)n);
1058 break;
1059 }
1060 case 'q': {
1061 addliteral(L, &b, arg);
1062 break;
1063 }
1064 case 's': {
1065 size_t l;
1066 const char *s = luaL_tolstring(L, arg, &l);
1067 if (form[2] == '\0') /* no modifiers? */
1068 luaL_addvalue(&b); /* keep entire string */
1069 else {
1070 luaL_argcheck(L, l == strlen(s), arg, "string contains zeros");
1071 if (!strchr(form, '.') && l >= 100) {
1072 /* no precision and string is too long to be formatted */
1073 luaL_addvalue(&b); /* keep entire string */
1074 }
1075 else { /* format the string into 'buff' */
1076 nb = l_sprintf(buff, MAX_ITEM, form, s);
1077 lua_pop(L, 1); /* remove result from 'luaL_tolstring' */
1078 }
1079 }
1080 break;
1081 }
1082 default: { /* also treat cases 'pnLlh' */
1083 return luaL_error(L, "invalid option '%%%c' to 'format'",
1084 *(strfrmt - 1));
1085 }
1086 }
1087 lua_assert(nb < MAX_ITEM);
1088 luaL_addsize(&b, nb);
1089 }
1090 }
1091 luaL_pushresult(&b);
1092 return 1;
1093}
1094
1095/* }====================================================== */
1096
1097
1098/*
1099** {======================================================
1100** PACK/UNPACK
1101** =======================================================
1102*/
1103
1104
1105/* value used for padding */
1106#if !defined(LUAL_PACKPADBYTE)
1107#define LUAL_PACKPADBYTE 0x00
1108#endif
1109
1110/* maximum size for the binary representation of an integer */
1111#define MAXINTSIZE 16
1112
1113/* number of bits in a character */
1114#define NB CHAR_BIT
1115
1116/* mask for one character (NB 1's) */
1117#define MC ((1 << NB) - 1)
1118
1119/* size of a lua_Integer */
1120#define SZINT ((int)sizeof(lua_Integer))
1121
1122
1123/* dummy union to get native endianness */
1124static const union {
1125 int dummy;
1126 char little; /* true iff machine is little endian */
1127} nativeendian = {1};
1128
1129
1130/* dummy structure to get native alignment requirements */
1131struct cD {
1132 char c;
1133 union { double d; void *p; lua_Integer i; lua_Number n; } u;
1134};
1135
1136#define MAXALIGN (offsetof(struct cD, u))
1137
1138
1139/*
1140** Union for serializing floats
1141*/
1142typedef union Ftypes {
1143 float f;
1144 double d;
1145 lua_Number n;
1146 char buff[5 * sizeof(lua_Number)]; /* enough for any float type */
1147} Ftypes;
1148
1149
1150/*
1151** information to pack/unpack stuff
1152*/
1153typedef struct Header {
1154 lua_State *L;
1155 int islittle;
1156 int maxalign;
1157} Header;
1158
1159
1160/*
1161** options for pack/unpack
1162*/
1163typedef enum KOption {
1164 Kint, /* signed integers */
1165 Kuint, /* unsigned integers */
1166 Kfloat, /* floating-point numbers */
1167 Kchar, /* fixed-length strings */
1168 Kstring, /* strings with prefixed length */
1169 Kzstr, /* zero-terminated strings */
1170 Kpadding, /* padding */
1171 Kpaddalign, /* padding for alignment */
1172 Knop /* no-op (configuration or spaces) */
1173} KOption;
1174
1175
1176/*
1177** Read an integer numeral from string 'fmt' or return 'df' if
1178** there is no numeral
1179*/
1180static int digit (int c) { return '0' <= c && c <= '9'; }
1181
1182static int getnum (const char **fmt, int df) {
1183 if (!digit(**fmt)) /* no number? */
1184 return df; /* return default value */
1185 else {
1186 int a = 0;
1187 do {
1188 a = a*10 + (*((*fmt)++) - '0');
1189 } while (digit(**fmt) && a <= ((int)MAXSIZE - 9)/10);
1190 return a;
1191 }
1192}
1193
1194
1195/*
1196** Read an integer numeral and raises an error if it is larger
1197** than the maximum size for integers.
1198*/
1199static int getnumlimit (Header *h, const char **fmt, int df) {
1200 int sz = getnum(fmt, df);
1201 if (sz > MAXINTSIZE || sz <= 0)
1202 return luaL_error(h->L, "integral size (%d) out of limits [1,%d]",
1203 sz, MAXINTSIZE);
1204 return sz;
1205}
1206
1207
1208/*
1209** Initialize Header
1210*/
1211static void initheader (lua_State *L, Header *h) {
1212 h->L = L;
1213 h->islittle = nativeendian.little;
1214 h->maxalign = 1;
1215}
1216
1217
1218/*
1219** Read and classify next option. 'size' is filled with option's size.
1220*/
1221static KOption getoption (Header *h, const char **fmt, int *size) {
1222 int opt = *((*fmt)++);
1223 *size = 0; /* default */
1224 switch (opt) {
1225 case 'b': *size = sizeof(char); return Kint;
1226 case 'B': *size = sizeof(char); return Kuint;
1227 case 'h': *size = sizeof(short); return Kint;
1228 case 'H': *size = sizeof(short); return Kuint;
1229 case 'l': *size = sizeof(long); return Kint;
1230 case 'L': *size = sizeof(long); return Kuint;
1231 case 'j': *size = sizeof(lua_Integer); return Kint;
1232 case 'J': *size = sizeof(lua_Integer); return Kuint;
1233 case 'T': *size = sizeof(size_t); return Kuint;
1234 case 'f': *size = sizeof(float); return Kfloat;
1235 case 'd': *size = sizeof(double); return Kfloat;
1236 case 'n': *size = sizeof(lua_Number); return Kfloat;
1237 case 'i': *size = getnumlimit(h, fmt, sizeof(int)); return Kint;
1238 case 'I': *size = getnumlimit(h, fmt, sizeof(int)); return Kuint;
1239 case 's': *size = getnumlimit(h, fmt, sizeof(size_t)); return Kstring;
1240 case 'c':
1241 *size = getnum(fmt, -1);
1242 if (*size == -1)
1243 luaL_error(h->L, "missing size for format option 'c'");
1244 return Kchar;
1245 case 'z': return Kzstr;
1246 case 'x': *size = 1; return Kpadding;
1247 case 'X': return Kpaddalign;
1248 case ' ': break;
1249 case '<': h->islittle = 1; break;
1250 case '>': h->islittle = 0; break;
1251 case '=': h->islittle = nativeendian.little; break;
1252 case '!': h->maxalign = getnumlimit(h, fmt, MAXALIGN); break;
1253 default: luaL_error(h->L, "invalid format option '%c'", opt);
1254 }
1255 return Knop;
1256}
1257
1258
1259/*
1260** Read, classify, and fill other details about the next option.
1261** 'psize' is filled with option's size, 'notoalign' with its
1262** alignment requirements.
1263** Local variable 'size' gets the size to be aligned. (Kpadal option
1264** always gets its full alignment, other options are limited by
1265** the maximum alignment ('maxalign'). Kchar option needs no alignment
1266** despite its size.
1267*/
1268static KOption getdetails (Header *h, size_t totalsize,
1269 const char **fmt, int *psize, int *ntoalign) {
1270 KOption opt = getoption(h, fmt, psize);
1271 int align = *psize; /* usually, alignment follows size */
1272 if (opt == Kpaddalign) { /* 'X' gets alignment from following option */
1273 if (**fmt == '\0' || getoption(h, fmt, &align) == Kchar || align == 0)
1274 luaL_argerror(h->L, 1, "invalid next option for option 'X'");
1275 }
1276 if (align <= 1 || opt == Kchar) /* need no alignment? */
1277 *ntoalign = 0;
1278 else {
1279 if (align > h->maxalign) /* enforce maximum alignment */
1280 align = h->maxalign;
1281 if ((align & (align - 1)) != 0) /* is 'align' not a power of 2? */
1282 luaL_argerror(h->L, 1, "format asks for alignment not power of 2");
1283 *ntoalign = (align - (int)(totalsize & (align - 1))) & (align - 1);
1284 }
1285 return opt;
1286}
1287
1288
1289/*
1290** Pack integer 'n' with 'size' bytes and 'islittle' endianness.
1291** The final 'if' handles the case when 'size' is larger than
1292** the size of a Lua integer, correcting the extra sign-extension
1293** bytes if necessary (by default they would be zeros).
1294*/
1295static void packint (luaL_Buffer *b, lua_Unsigned n,
1296 int islittle, int size, int neg) {
1297 char *buff = luaL_prepbuffsize(b, size);
1298 int i;
1299 buff[islittle ? 0 : size - 1] = (char)(n & MC); /* first byte */
1300 for (i = 1; i < size; i++) {
1301 n >>= NB;
1302 buff[islittle ? i : size - 1 - i] = (char)(n & MC);
1303 }
1304 if (neg && size > SZINT) { /* negative number need sign extension? */
1305 for (i = SZINT; i < size; i++) /* correct extra bytes */
1306 buff[islittle ? i : size - 1 - i] = (char)MC;
1307 }
1308 luaL_addsize(b, size); /* add result to buffer */
1309}
1310
1311
1312/*
1313** Copy 'size' bytes from 'src' to 'dest', correcting endianness if
1314** given 'islittle' is different from native endianness.
1315*/
1316static void copywithendian (volatile char *dest, volatile const char *src,
1317 int size, int islittle) {
1318 if (islittle == nativeendian.little) {
1319 while (size-- != 0)
1320 *(dest++) = *(src++);
1321 }
1322 else {
1323 dest += size - 1;
1324 while (size-- != 0)
1325 *(dest--) = *(src++);
1326 }
1327}
1328
1329
1330static int str_pack (lua_State *L) {
1331 luaL_Buffer b;
1332 Header h;
1333 const char *fmt = luaL_checkstring(L, 1); /* format string */
1334 int arg = 1; /* current argument to pack */
1335 size_t totalsize = 0; /* accumulate total size of result */
1336 initheader(L, &h);
1337 lua_pushnil(L); /* mark to separate arguments from string buffer */
1338 luaL_buffinit(L, &b);
1339 while (*fmt != '\0') {
1340 int size, ntoalign;
1341 KOption opt = getdetails(&h, totalsize, &fmt, &size, &ntoalign);
1342 totalsize += ntoalign + size;
1343 while (ntoalign-- > 0)
1344 luaL_addchar(&b, LUAL_PACKPADBYTE); /* fill alignment */
1345 arg++;
1346 switch (opt) {
1347 case Kint: { /* signed integers */
1348 lua_Integer n = luaL_checkinteger(L, arg);
1349 if (size < SZINT) { /* need overflow check? */
1350 lua_Integer lim = (lua_Integer)1 << ((size * NB) - 1);
1351 luaL_argcheck(L, -lim <= n && n < lim, arg, "integer overflow");
1352 }
1353 packint(&b, (lua_Unsigned)n, h.islittle, size, (n < 0));
1354 break;
1355 }
1356 case Kuint: { /* unsigned integers */
1357 lua_Integer n = luaL_checkinteger(L, arg);
1358 if (size < SZINT) /* need overflow check? */
1359 luaL_argcheck(L, (lua_Unsigned)n < ((lua_Unsigned)1 << (size * NB)),
1360 arg, "unsigned overflow");
1361 packint(&b, (lua_Unsigned)n, h.islittle, size, 0);
1362 break;
1363 }
1364 case Kfloat: { /* floating-point options */
1365 volatile Ftypes u;
1366 char *buff = luaL_prepbuffsize(&b, size);
1367 lua_Number n = luaL_checknumber(L, arg); /* get argument */
1368 if (size == sizeof(u.f)) u.f = (float)n; /* copy it into 'u' */
1369 else if (size == sizeof(u.d)) u.d = (double)n;
1370 else u.n = n;
1371 /* move 'u' to final result, correcting endianness if needed */
1372 copywithendian(buff, u.buff, size, h.islittle);
1373 luaL_addsize(&b, size);
1374 break;
1375 }
1376 case Kchar: { /* fixed-size string */
1377 size_t len;
1378 const char *s = luaL_checklstring(L, arg, &len);
1379 luaL_argcheck(L, len <= (size_t)size, arg,
1380 "string longer than given size");
1381 luaL_addlstring(&b, s, len); /* add string */
1382 while (len++ < (size_t)size) /* pad extra space */
1383 luaL_addchar(&b, LUAL_PACKPADBYTE);
1384 break;
1385 }
1386 case Kstring: { /* strings with length count */
1387 size_t len;
1388 const char *s = luaL_checklstring(L, arg, &len);
1389 luaL_argcheck(L, size >= (int)sizeof(size_t) ||
1390 len < ((size_t)1 << (size * NB)),
1391 arg, "string length does not fit in given size");
1392 packint(&b, (lua_Unsigned)len, h.islittle, size, 0); /* pack length */
1393 luaL_addlstring(&b, s, len);
1394 totalsize += len;
1395 break;
1396 }
1397 case Kzstr: { /* zero-terminated string */
1398 size_t len;
1399 const char *s = luaL_checklstring(L, arg, &len);
1400 luaL_argcheck(L, strlen(s) == len, arg, "string contains zeros");
1401 luaL_addlstring(&b, s, len);
1402 luaL_addchar(&b, '\0'); /* add zero at the end */
1403 totalsize += len + 1;
1404 break;
1405 }
1406 case Kpadding: luaL_addchar(&b, LUAL_PACKPADBYTE); /* FALLTHROUGH */
1407 case Kpaddalign: case Knop:
1408 arg--; /* undo increment */
1409 break;
1410 }
1411 }
1412 luaL_pushresult(&b);
1413 return 1;
1414}
1415
1416
1417static int str_packsize (lua_State *L) {
1418 Header h;
1419 const char *fmt = luaL_checkstring(L, 1); /* format string */
1420 size_t totalsize = 0; /* accumulate total size of result */
1421 initheader(L, &h);
1422 while (*fmt != '\0') {
1423 int size, ntoalign;
1424 KOption opt = getdetails(&h, totalsize, &fmt, &size, &ntoalign);
1425 size += ntoalign; /* total space used by option */
1426 luaL_argcheck(L, totalsize <= MAXSIZE - size, 1,
1427 "format result too large");
1428 totalsize += size;
1429 switch (opt) {
1430 case Kstring: /* strings with length count */
1431 case Kzstr: /* zero-terminated string */
1432 luaL_argerror(L, 1, "variable-length format");
1433 /* call never return, but to avoid warnings: *//* FALLTHROUGH */
1434 default: break;
1435 }
1436 }
1437 lua_pushinteger(L, (lua_Integer)totalsize);
1438 return 1;
1439}
1440
1441
1442/*
1443** Unpack an integer with 'size' bytes and 'islittle' endianness.
1444** If size is smaller than the size of a Lua integer and integer
1445** is signed, must do sign extension (propagating the sign to the
1446** higher bits); if size is larger than the size of a Lua integer,
1447** it must check the unread bytes to see whether they do not cause an
1448** overflow.
1449*/
1450static lua_Integer unpackint (lua_State *L, const char *str,
1451 int islittle, int size, int issigned) {
1452 lua_Unsigned res = 0;
1453 int i;
1454 int limit = (size <= SZINT) ? size : SZINT;
1455 for (i = limit - 1; i >= 0; i--) {
1456 res <<= NB;
1457 res |= (lua_Unsigned)(unsigned char)str[islittle ? i : size - 1 - i];
1458 }
1459 if (size < SZINT) { /* real size smaller than lua_Integer? */
1460 if (issigned) { /* needs sign extension? */
1461 lua_Unsigned mask = (lua_Unsigned)1 << (size*NB - 1);
1462 res = ((res ^ mask) - mask); /* do sign extension */
1463 }
1464 }
1465 else if (size > SZINT) { /* must check unread bytes */
1466 int mask = (!issigned || (lua_Integer)res >= 0) ? 0 : MC;
1467 for (i = limit; i < size; i++) {
1468 if ((unsigned char)str[islittle ? i : size - 1 - i] != mask)
1469 luaL_error(L, "%d-byte integer does not fit into Lua Integer", size);
1470 }
1471 }
1472 return (lua_Integer)res;
1473}
1474
1475
1476static int str_unpack (lua_State *L) {
1477 Header h;
1478 const char *fmt = luaL_checkstring(L, 1);
1479 size_t ld;
1480 const char *data = luaL_checklstring(L, 2, &ld);
1481 size_t pos = (size_t)posrelat(luaL_optinteger(L, 3, 1), ld) - 1;
1482 int n = 0; /* number of results */
1483 luaL_argcheck(L, pos <= ld, 3, "initial position out of string");
1484 initheader(L, &h);
1485 while (*fmt != '\0') {
1486 int size, ntoalign;
1487 KOption opt = getdetails(&h, pos, &fmt, &size, &ntoalign);
1488 if ((size_t)ntoalign + size > ~pos || pos + ntoalign + size > ld)
1489 luaL_argerror(L, 2, "data string too short");
1490 pos += ntoalign; /* skip alignment */
1491 /* stack space for item + next position */
1492 luaL_checkstack(L, 2, "too many results");
1493 n++;
1494 switch (opt) {
1495 case Kint:
1496 case Kuint: {
1497 lua_Integer res = unpackint(L, data + pos, h.islittle, size,
1498 (opt == Kint));
1499 lua_pushinteger(L, res);
1500 break;
1501 }
1502 case Kfloat: {
1503 volatile Ftypes u;
1504 lua_Number num;
1505 copywithendian(u.buff, data + pos, size, h.islittle);
1506 if (size == sizeof(u.f)) num = (lua_Number)u.f;
1507 else if (size == sizeof(u.d)) num = (lua_Number)u.d;
1508 else num = u.n;
1509 lua_pushnumber(L, num);
1510 break;
1511 }
1512 case Kchar: {
1513 lua_pushlstring(L, data + pos, size);
1514 break;
1515 }
1516 case Kstring: {
1517 size_t len = (size_t)unpackint(L, data + pos, h.islittle, size, 0);
1518 luaL_argcheck(L, pos + len + size <= ld, 2, "data string too short");
1519 lua_pushlstring(L, data + pos + size, len);
1520 pos += len; /* skip string */
1521 break;
1522 }
1523 case Kzstr: {
1524 size_t len = (int)strlen(data + pos);
1525 lua_pushlstring(L, data + pos, len);
1526 pos += len + 1; /* skip string plus final '\0' */
1527 break;
1528 }
1529 case Kpaddalign: case Kpadding: case Knop:
1530 n--; /* undo increment */
1531 break;
1532 }
1533 pos += size;
1534 }
1535 lua_pushinteger(L, pos + 1); /* next position */
1536 return n + 1;
1537}
1538
1539/* }====================================================== */
1540
1541
1542static const luaL_Reg strlib[] = {
1543 {"byte", str_byte},
1544 {"char", str_char},
1545 {"dump", str_dump},
1546 {"find", str_find},
1547 {"format", str_format},
1548 {"gmatch", gmatch},
1549 {"gsub", str_gsub},
1550 {"len", str_len},
1551 {"lower", str_lower},
1552 {"match", str_match},
1553 {"rep", str_rep},
1554 {"reverse", str_reverse},
1555 {"sub", str_sub},
1556 {"upper", str_upper},
1557 {"pack", str_pack},
1558 {"packsize", str_packsize},
1559 {"unpack", str_unpack},
1560 {NULL, NULL}
1561};
1562
1563
1564static void createmetatable (lua_State *L) {
1565 lua_createtable(L, 0, 1); /* table to be metatable for strings */
1566 lua_pushliteral(L, ""); /* dummy string */
1567 lua_pushvalue(L, -2); /* copy table */
1568 lua_setmetatable(L, -2); /* set table as metatable for strings */
1569 lua_pop(L, 1); /* pop dummy string */
1570 lua_pushvalue(L, -2); /* get string library */
1571 lua_setfield(L, -2, "__index"); /* metatable.__index = string */
1572 lua_pop(L, 1); /* pop metatable */
1573}
1574
1575
1576/*
1577** Open string library
1578*/
1579LUAMOD_API int luaopen_string (lua_State *L) {
1580 luaL_newlib(L, strlib);
1581 createmetatable(L);
1582 return 1;
1583}
1584
1585