1/*
2** $Id: lstrlib.c $
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 <math.h>
18#include <stddef.h>
19#include <stdio.h>
20#include <stdlib.h>
21#include <string.h>
22
23#include "lua.h"
24
25#include "lauxlib.h"
26#include "lualib.h"
27
28
29/*
30** maximum number of captures that a pattern can do during
31** pattern-matching. This limit is arbitrary, but must fit in
32** an unsigned char.
33*/
34#if !defined(LUA_MAXCAPTURES)
35#define LUA_MAXCAPTURES 32
36#endif
37
38
39/* macro to 'unsign' a character */
40#define uchar(c) ((unsigned char)(c))
41
42
43/*
44** Some sizes are better limited to fit in 'int', but must also fit in
45** 'size_t'. (We assume that 'lua_Integer' cannot be smaller than 'int'.)
46*/
47#define MAX_SIZET ((size_t)(~(size_t)0))
48
49#define MAXSIZE \
50 (sizeof(size_t) < sizeof(int) ? MAX_SIZET : (size_t)(INT_MAX))
51
52
53
54
55static int str_len (lua_State *L) {
56 size_t l;
57 luaL_checklstring(L, 1, &l);
58 lua_pushinteger(L, (lua_Integer)l);
59 return 1;
60}
61
62
63/*
64** translate a relative initial string position
65** (negative means back from end): clip result to [1, inf).
66** The length of any string in Lua must fit in a lua_Integer,
67** so there are no overflows in the casts.
68** The inverted comparison avoids a possible overflow
69** computing '-pos'.
70*/
71static size_t posrelatI (lua_Integer pos, size_t len) {
72 if (pos > 0)
73 return (size_t)pos;
74 else if (pos == 0)
75 return 1;
76 else if (pos < -(lua_Integer)len) /* inverted comparison */
77 return 1; /* clip to 1 */
78 else return len + (size_t)pos + 1;
79}
80
81
82/*
83** Gets an optional ending string position from argument 'arg',
84** with default value 'def'.
85** Negative means back from end: clip result to [0, len]
86*/
87static size_t getendpos (lua_State *L, int arg, lua_Integer def,
88 size_t len) {
89 lua_Integer pos = luaL_optinteger(L, arg, def);
90 if (pos > (lua_Integer)len)
91 return len;
92 else if (pos >= 0)
93 return (size_t)pos;
94 else if (pos < -(lua_Integer)len)
95 return 0;
96 else return len + (size_t)pos + 1;
97}
98
99
100static int str_sub (lua_State *L) {
101 size_t l;
102 const char *s = luaL_checklstring(L, 1, &l);
103 size_t start = posrelatI(luaL_checkinteger(L, 2), l);
104 size_t end = getendpos(L, 3, -1, l);
105 if (start <= end)
106 lua_pushlstring(L, s + start - 1, (end - start) + 1);
107 else lua_pushliteral(L, "");
108 return 1;
109}
110
111
112static int str_reverse (lua_State *L) {
113 size_t l, i;
114 luaL_Buffer b;
115 const char *s = luaL_checklstring(L, 1, &l);
116 char *p = luaL_buffinitsize(L, &b, l);
117 for (i = 0; i < l; i++)
118 p[i] = s[l - i - 1];
119 luaL_pushresultsize(&b, l);
120 return 1;
121}
122
123
124static int str_lower (lua_State *L) {
125 size_t l;
126 size_t i;
127 luaL_Buffer b;
128 const char *s = luaL_checklstring(L, 1, &l);
129 char *p = luaL_buffinitsize(L, &b, l);
130 for (i=0; i<l; i++)
131 p[i] = tolower(uchar(s[i]));
132 luaL_pushresultsize(&b, l);
133 return 1;
134}
135
136
137static int str_upper (lua_State *L) {
138 size_t l;
139 size_t i;
140 luaL_Buffer b;
141 const char *s = luaL_checklstring(L, 1, &l);
142 char *p = luaL_buffinitsize(L, &b, l);
143 for (i=0; i<l; i++)
144 p[i] = toupper(uchar(s[i]));
145 luaL_pushresultsize(&b, l);
146 return 1;
147}
148
149
150static int str_rep (lua_State *L) {
151 size_t l, lsep;
152 const char *s = luaL_checklstring(L, 1, &l);
153 lua_Integer n = luaL_checkinteger(L, 2);
154 const char *sep = luaL_optlstring(L, 3, "", &lsep);
155 if (n <= 0)
156 lua_pushliteral(L, "");
157 else if (l_unlikely(l + lsep < l || l + lsep > MAXSIZE / n))
158 return luaL_error(L, "resulting string too large");
159 else {
160 size_t totallen = (size_t)n * l + (size_t)(n - 1) * lsep;
161 luaL_Buffer b;
162 char *p = luaL_buffinitsize(L, &b, totallen);
163 while (n-- > 1) { /* first n-1 copies (followed by separator) */
164 memcpy(p, s, l * sizeof(char)); p += l;
165 if (lsep > 0) { /* empty 'memcpy' is not that cheap */
166 memcpy(p, sep, lsep * sizeof(char));
167 p += lsep;
168 }
169 }
170 memcpy(p, s, l * sizeof(char)); /* last copy (not followed by separator) */
171 luaL_pushresultsize(&b, totallen);
172 }
173 return 1;
174}
175
176
177static int str_byte (lua_State *L) {
178 size_t l;
179 const char *s = luaL_checklstring(L, 1, &l);
180 lua_Integer pi = luaL_optinteger(L, 2, 1);
181 size_t posi = posrelatI(pi, l);
182 size_t pose = getendpos(L, 3, pi, l);
183 int n, i;
184 if (posi > pose) return 0; /* empty interval; return no values */
185 if (l_unlikely(pose - posi >= (size_t)INT_MAX)) /* arithmetic overflow? */
186 return luaL_error(L, "string slice too long");
187 n = (int)(pose - posi) + 1;
188 luaL_checkstack(L, n, "string slice too long");
189 for (i=0; i<n; i++)
190 lua_pushinteger(L, uchar(s[posi+i-1]));
191 return n;
192}
193
194
195static int str_char (lua_State *L) {
196 int n = lua_gettop(L); /* number of arguments */
197 int i;
198 luaL_Buffer b;
199 char *p = luaL_buffinitsize(L, &b, n);
200 for (i=1; i<=n; i++) {
201 lua_Unsigned c = (lua_Unsigned)luaL_checkinteger(L, i);
202 luaL_argcheck(L, c <= (lua_Unsigned)UCHAR_MAX, i, "value out of range");
203 p[i - 1] = uchar(c);
204 }
205 luaL_pushresultsize(&b, n);
206 return 1;
207}
208
209
210/*
211** Buffer to store the result of 'string.dump'. It must be initialized
212** after the call to 'lua_dump', to ensure that the function is on the
213** top of the stack when 'lua_dump' is called. ('luaL_buffinit' might
214** push stuff.)
215*/
216struct str_Writer {
217 int init; /* true iff buffer has been initialized */
218 luaL_Buffer B;
219};
220
221
222static int writer (lua_State *L, const void *b, size_t size, void *ud) {
223 struct str_Writer *state = (struct str_Writer *)ud;
224 if (!state->init) {
225 state->init = 1;
226 luaL_buffinit(L, &state->B);
227 }
228 luaL_addlstring(&state->B, (const char *)b, size);
229 return 0;
230}
231
232
233static int str_dump (lua_State *L) {
234 struct str_Writer state;
235 int strip = lua_toboolean(L, 2);
236 luaL_checktype(L, 1, LUA_TFUNCTION);
237 lua_settop(L, 1); /* ensure function is on the top of the stack */
238 state.init = 0;
239 if (l_unlikely(lua_dump(L, writer, &state, strip) != 0))
240 return luaL_error(L, "unable to dump given function");
241 luaL_pushresult(&state.B);
242 return 1;
243}
244
245
246
247/*
248** {======================================================
249** METAMETHODS
250** =======================================================
251*/
252
253#if defined(LUA_NOCVTS2N) /* { */
254
255/* no coercion from strings to numbers */
256
257static const luaL_Reg stringmetamethods[] = {
258 {"__index", NULL}, /* placeholder */
259 {NULL, NULL}
260};
261
262#else /* }{ */
263
264static int tonum (lua_State *L, int arg) {
265 if (lua_type(L, arg) == LUA_TNUMBER) { /* already a number? */
266 lua_pushvalue(L, arg);
267 return 1;
268 }
269 else { /* check whether it is a numerical string */
270 size_t len;
271 const char *s = lua_tolstring(L, arg, &len);
272 return (s != NULL && lua_stringtonumber(L, s) == len + 1);
273 }
274}
275
276
277static void trymt (lua_State *L, const char *mtname) {
278 lua_settop(L, 2); /* back to the original arguments */
279 if (l_unlikely(lua_type(L, 2) == LUA_TSTRING ||
280 !luaL_getmetafield(L, 2, mtname)))
281 luaL_error(L, "attempt to %s a '%s' with a '%s'", mtname + 2,
282 luaL_typename(L, -2), luaL_typename(L, -1));
283 lua_insert(L, -3); /* put metamethod before arguments */
284 lua_call(L, 2, 1); /* call metamethod */
285}
286
287
288static int arith (lua_State *L, int op, const char *mtname) {
289 if (tonum(L, 1) && tonum(L, 2))
290 lua_arith(L, op); /* result will be on the top */
291 else
292 trymt(L, mtname);
293 return 1;
294}
295
296
297static int arith_add (lua_State *L) {
298 return arith(L, LUA_OPADD, "__add");
299}
300
301static int arith_sub (lua_State *L) {
302 return arith(L, LUA_OPSUB, "__sub");
303}
304
305static int arith_mul (lua_State *L) {
306 return arith(L, LUA_OPMUL, "__mul");
307}
308
309static int arith_mod (lua_State *L) {
310 return arith(L, LUA_OPMOD, "__mod");
311}
312
313static int arith_pow (lua_State *L) {
314 return arith(L, LUA_OPPOW, "__pow");
315}
316
317static int arith_div (lua_State *L) {
318 return arith(L, LUA_OPDIV, "__div");
319}
320
321static int arith_idiv (lua_State *L) {
322 return arith(L, LUA_OPIDIV, "__idiv");
323}
324
325static int arith_unm (lua_State *L) {
326 return arith(L, LUA_OPUNM, "__unm");
327}
328
329
330static const luaL_Reg stringmetamethods[] = {
331 {"__add", arith_add},
332 {"__sub", arith_sub},
333 {"__mul", arith_mul},
334 {"__mod", arith_mod},
335 {"__pow", arith_pow},
336 {"__div", arith_div},
337 {"__idiv", arith_idiv},
338 {"__unm", arith_unm},
339 {"__index", NULL}, /* placeholder */
340 {NULL, NULL}
341};
342
343#endif /* } */
344
345/* }====================================================== */
346
347/*
348** {======================================================
349** PATTERN MATCHING
350** =======================================================
351*/
352
353
354#define CAP_UNFINISHED (-1)
355#define CAP_POSITION (-2)
356
357
358typedef struct MatchState {
359 const char *src_init; /* init of source string */
360 const char *src_end; /* end ('\0') of source string */
361 const char *p_end; /* end ('\0') of pattern */
362 lua_State *L;
363 int matchdepth; /* control for recursive depth (to avoid C stack overflow) */
364 unsigned char level; /* total number of captures (finished or unfinished) */
365 struct {
366 const char *init;
367 ptrdiff_t len;
368 } capture[LUA_MAXCAPTURES];
369} MatchState;
370
371
372/* recursive function */
373static const char *match (MatchState *ms, const char *s, const char *p);
374
375
376/* maximum recursion depth for 'match' */
377#if !defined(MAXCCALLS)
378#define MAXCCALLS 200
379#endif
380
381
382#define L_ESC '%'
383#define SPECIALS "^$*+?.([%-"
384
385
386static int check_capture (MatchState *ms, int l) {
387 l -= '1';
388 if (l_unlikely(l < 0 || l >= ms->level ||
389 ms->capture[l].len == CAP_UNFINISHED))
390 return luaL_error(ms->L, "invalid capture index %%%d", l + 1);
391 return l;
392}
393
394
395static int capture_to_close (MatchState *ms) {
396 int level = ms->level;
397 for (level--; level>=0; level--)
398 if (ms->capture[level].len == CAP_UNFINISHED) return level;
399 return luaL_error(ms->L, "invalid pattern capture");
400}
401
402
403static const char *classend (MatchState *ms, const char *p) {
404 switch (*p++) {
405 case L_ESC: {
406 if (l_unlikely(p == ms->p_end))
407 luaL_error(ms->L, "malformed pattern (ends with '%%')");
408 return p+1;
409 }
410 case '[': {
411 if (*p == '^') p++;
412 do { /* look for a ']' */
413 if (l_unlikely(p == ms->p_end))
414 luaL_error(ms->L, "malformed pattern (missing ']')");
415 if (*(p++) == L_ESC && p < ms->p_end)
416 p++; /* skip escapes (e.g. '%]') */
417 } while (*p != ']');
418 return p+1;
419 }
420 default: {
421 return p;
422 }
423 }
424}
425
426
427static int match_class (int c, int cl) {
428 int res;
429 switch (tolower(cl)) {
430 case 'a' : res = isalpha(c); break;
431 case 'c' : res = iscntrl(c); break;
432 case 'd' : res = isdigit(c); break;
433 case 'g' : res = isgraph(c); break;
434 case 'l' : res = islower(c); break;
435 case 'p' : res = ispunct(c); break;
436 case 's' : res = isspace(c); break;
437 case 'u' : res = isupper(c); break;
438 case 'w' : res = isalnum(c); break;
439 case 'x' : res = isxdigit(c); break;
440 case 'z' : res = (c == 0); break; /* deprecated option */
441 default: return (cl == c);
442 }
443 return (islower(cl) ? res : !res);
444}
445
446
447static int matchbracketclass (int c, const char *p, const char *ec) {
448 int sig = 1;
449 if (*(p+1) == '^') {
450 sig = 0;
451 p++; /* skip the '^' */
452 }
453 while (++p < ec) {
454 if (*p == L_ESC) {
455 p++;
456 if (match_class(c, uchar(*p)))
457 return sig;
458 }
459 else if ((*(p+1) == '-') && (p+2 < ec)) {
460 p+=2;
461 if (uchar(*(p-2)) <= c && c <= uchar(*p))
462 return sig;
463 }
464 else if (uchar(*p) == c) return sig;
465 }
466 return !sig;
467}
468
469
470static int singlematch (MatchState *ms, const char *s, const char *p,
471 const char *ep) {
472 if (s >= ms->src_end)
473 return 0;
474 else {
475 int c = uchar(*s);
476 switch (*p) {
477 case '.': return 1; /* matches any char */
478 case L_ESC: return match_class(c, uchar(*(p+1)));
479 case '[': return matchbracketclass(c, p, ep-1);
480 default: return (uchar(*p) == c);
481 }
482 }
483}
484
485
486static const char *matchbalance (MatchState *ms, const char *s,
487 const char *p) {
488 if (l_unlikely(p >= ms->p_end - 1))
489 luaL_error(ms->L, "malformed pattern (missing arguments to '%%b')");
490 if (*s != *p) return NULL;
491 else {
492 int b = *p;
493 int e = *(p+1);
494 int cont = 1;
495 while (++s < ms->src_end) {
496 if (*s == e) {
497 if (--cont == 0) return s+1;
498 }
499 else if (*s == b) cont++;
500 }
501 }
502 return NULL; /* string ends out of balance */
503}
504
505
506static const char *max_expand (MatchState *ms, const char *s,
507 const char *p, const char *ep) {
508 ptrdiff_t i = 0; /* counts maximum expand for item */
509 while (singlematch(ms, s + i, p, ep))
510 i++;
511 /* keeps trying to match with the maximum repetitions */
512 while (i>=0) {
513 const char *res = match(ms, (s+i), ep+1);
514 if (res) return res;
515 i--; /* else didn't match; reduce 1 repetition to try again */
516 }
517 return NULL;
518}
519
520
521static const char *min_expand (MatchState *ms, const char *s,
522 const char *p, const char *ep) {
523 for (;;) {
524 const char *res = match(ms, s, ep+1);
525 if (res != NULL)
526 return res;
527 else if (singlematch(ms, s, p, ep))
528 s++; /* try with one more repetition */
529 else return NULL;
530 }
531}
532
533
534static const char *start_capture (MatchState *ms, const char *s,
535 const char *p, int what) {
536 const char *res;
537 int level = ms->level;
538 if (level >= LUA_MAXCAPTURES) luaL_error(ms->L, "too many captures");
539 ms->capture[level].init = s;
540 ms->capture[level].len = what;
541 ms->level = level+1;
542 if ((res=match(ms, s, p)) == NULL) /* match failed? */
543 ms->level--; /* undo capture */
544 return res;
545}
546
547
548static const char *end_capture (MatchState *ms, const char *s,
549 const char *p) {
550 int l = capture_to_close(ms);
551 const char *res;
552 ms->capture[l].len = s - ms->capture[l].init; /* close capture */
553 if ((res = match(ms, s, p)) == NULL) /* match failed? */
554 ms->capture[l].len = CAP_UNFINISHED; /* undo capture */
555 return res;
556}
557
558
559static const char *match_capture (MatchState *ms, const char *s, int l) {
560 size_t len;
561 l = check_capture(ms, l);
562 len = ms->capture[l].len;
563 if ((size_t)(ms->src_end-s) >= len &&
564 memcmp(ms->capture[l].init, s, len) == 0)
565 return s+len;
566 else return NULL;
567}
568
569
570static const char *match (MatchState *ms, const char *s, const char *p) {
571 if (l_unlikely(ms->matchdepth-- == 0))
572 luaL_error(ms->L, "pattern too complex");
573 init: /* using goto to optimize tail recursion */
574 if (p != ms->p_end) { /* end of pattern? */
575 switch (*p) {
576 case '(': { /* start capture */
577 if (*(p + 1) == ')') /* position capture? */
578 s = start_capture(ms, s, p + 2, CAP_POSITION);
579 else
580 s = start_capture(ms, s, p + 1, CAP_UNFINISHED);
581 break;
582 }
583 case ')': { /* end capture */
584 s = end_capture(ms, s, p + 1);
585 break;
586 }
587 case '$': {
588 if ((p + 1) != ms->p_end) /* is the '$' the last char in pattern? */
589 goto dflt; /* no; go to default */
590 s = (s == ms->src_end) ? s : NULL; /* check end of string */
591 break;
592 }
593 case L_ESC: { /* escaped sequences not in the format class[*+?-]? */
594 switch (*(p + 1)) {
595 case 'b': { /* balanced string? */
596 s = matchbalance(ms, s, p + 2);
597 if (s != NULL) {
598 p += 4; goto init; /* return match(ms, s, p + 4); */
599 } /* else fail (s == NULL) */
600 break;
601 }
602 case 'f': { /* frontier? */
603 const char *ep; char previous;
604 p += 2;
605 if (l_unlikely(*p != '['))
606 luaL_error(ms->L, "missing '[' after '%%f' in pattern");
607 ep = classend(ms, p); /* points to what is next */
608 previous = (s == ms->src_init) ? '\0' : *(s - 1);
609 if (!matchbracketclass(uchar(previous), p, ep - 1) &&
610 matchbracketclass(uchar(*s), p, ep - 1)) {
611 p = ep; goto init; /* return match(ms, s, ep); */
612 }
613 s = NULL; /* match failed */
614 break;
615 }
616 case '0': case '1': case '2': case '3':
617 case '4': case '5': case '6': case '7':
618 case '8': case '9': { /* capture results (%0-%9)? */
619 s = match_capture(ms, s, uchar(*(p + 1)));
620 if (s != NULL) {
621 p += 2; goto init; /* return match(ms, s, p + 2) */
622 }
623 break;
624 }
625 default: goto dflt;
626 }
627 break;
628 }
629 default: dflt: { /* pattern class plus optional suffix */
630 const char *ep = classend(ms, p); /* points to optional suffix */
631 /* does not match at least once? */
632 if (!singlematch(ms, s, p, ep)) {
633 if (*ep == '*' || *ep == '?' || *ep == '-') { /* accept empty? */
634 p = ep + 1; goto init; /* return match(ms, s, ep + 1); */
635 }
636 else /* '+' or no suffix */
637 s = NULL; /* fail */
638 }
639 else { /* matched once */
640 switch (*ep) { /* handle optional suffix */
641 case '?': { /* optional */
642 const char *res;
643 if ((res = match(ms, s + 1, ep + 1)) != NULL)
644 s = res;
645 else {
646 p = ep + 1; goto init; /* else return match(ms, s, ep + 1); */
647 }
648 break;
649 }
650 case '+': /* 1 or more repetitions */
651 s++; /* 1 match already done */
652 /* FALLTHROUGH */
653 case '*': /* 0 or more repetitions */
654 s = max_expand(ms, s, p, ep);
655 break;
656 case '-': /* 0 or more repetitions (minimum) */
657 s = min_expand(ms, s, p, ep);
658 break;
659 default: /* no suffix */
660 s++; p = ep; goto init; /* return match(ms, s + 1, ep); */
661 }
662 }
663 break;
664 }
665 }
666 }
667 ms->matchdepth++;
668 return s;
669}
670
671
672
673static const char *lmemfind (const char *s1, size_t l1,
674 const char *s2, size_t l2) {
675 if (l2 == 0) return s1; /* empty strings are everywhere */
676 else if (l2 > l1) return NULL; /* avoids a negative 'l1' */
677 else {
678 const char *init; /* to search for a '*s2' inside 's1' */
679 l2--; /* 1st char will be checked by 'memchr' */
680 l1 = l1-l2; /* 's2' cannot be found after that */
681 while (l1 > 0 && (init = (const char *)memchr(s1, *s2, l1)) != NULL) {
682 init++; /* 1st char is already checked */
683 if (memcmp(init, s2+1, l2) == 0)
684 return init-1;
685 else { /* correct 'l1' and 's1' to try again */
686 l1 -= init-s1;
687 s1 = init;
688 }
689 }
690 return NULL; /* not found */
691 }
692}
693
694
695/*
696** get information about the i-th capture. If there are no captures
697** and 'i==0', return information about the whole match, which
698** is the range 's'..'e'. If the capture is a string, return
699** its length and put its address in '*cap'. If it is an integer
700** (a position), push it on the stack and return CAP_POSITION.
701*/
702static size_t get_onecapture (MatchState *ms, int i, const char *s,
703 const char *e, const char **cap) {
704 if (i >= ms->level) {
705 if (l_unlikely(i != 0))
706 luaL_error(ms->L, "invalid capture index %%%d", i + 1);
707 *cap = s;
708 return e - s;
709 }
710 else {
711 ptrdiff_t capl = ms->capture[i].len;
712 *cap = ms->capture[i].init;
713 if (l_unlikely(capl == CAP_UNFINISHED))
714 luaL_error(ms->L, "unfinished capture");
715 else if (capl == CAP_POSITION)
716 lua_pushinteger(ms->L, (ms->capture[i].init - ms->src_init) + 1);
717 return capl;
718 }
719}
720
721
722/*
723** Push the i-th capture on the stack.
724*/
725static void push_onecapture (MatchState *ms, int i, const char *s,
726 const char *e) {
727 const char *cap;
728 ptrdiff_t l = get_onecapture(ms, i, s, e, &cap);
729 if (l != CAP_POSITION)
730 lua_pushlstring(ms->L, cap, l);
731 /* else position was already pushed */
732}
733
734
735static int push_captures (MatchState *ms, const char *s, const char *e) {
736 int i;
737 int nlevels = (ms->level == 0 && s) ? 1 : ms->level;
738 luaL_checkstack(ms->L, nlevels, "too many captures");
739 for (i = 0; i < nlevels; i++)
740 push_onecapture(ms, i, s, e);
741 return nlevels; /* number of strings pushed */
742}
743
744
745/* check whether pattern has no special characters */
746static int nospecials (const char *p, size_t l) {
747 size_t upto = 0;
748 do {
749 if (strpbrk(p + upto, SPECIALS))
750 return 0; /* pattern has a special character */
751 upto += strlen(p + upto) + 1; /* may have more after \0 */
752 } while (upto <= l);
753 return 1; /* no special chars found */
754}
755
756
757static void prepstate (MatchState *ms, lua_State *L,
758 const char *s, size_t ls, const char *p, size_t lp) {
759 ms->L = L;
760 ms->matchdepth = MAXCCALLS;
761 ms->src_init = s;
762 ms->src_end = s + ls;
763 ms->p_end = p + lp;
764}
765
766
767static void reprepstate (MatchState *ms) {
768 ms->level = 0;
769 lua_assert(ms->matchdepth == MAXCCALLS);
770}
771
772
773static int str_find_aux (lua_State *L, int find) {
774 size_t ls, lp;
775 const char *s = luaL_checklstring(L, 1, &ls);
776 const char *p = luaL_checklstring(L, 2, &lp);
777 size_t init = posrelatI(luaL_optinteger(L, 3, 1), ls) - 1;
778 if (init > ls) { /* start after string's end? */
779 luaL_pushfail(L); /* cannot find anything */
780 return 1;
781 }
782 /* explicit request or no special characters? */
783 if (find && (lua_toboolean(L, 4) || nospecials(p, lp))) {
784 /* do a plain search */
785 const char *s2 = lmemfind(s + init, ls - init, p, lp);
786 if (s2) {
787 lua_pushinteger(L, (s2 - s) + 1);
788 lua_pushinteger(L, (s2 - s) + lp);
789 return 2;
790 }
791 }
792 else {
793 MatchState ms;
794 const char *s1 = s + init;
795 int anchor = (*p == '^');
796 if (anchor) {
797 p++; lp--; /* skip anchor character */
798 }
799 prepstate(&ms, L, s, ls, p, lp);
800 do {
801 const char *res;
802 reprepstate(&ms);
803 if ((res=match(&ms, s1, p)) != NULL) {
804 if (find) {
805 lua_pushinteger(L, (s1 - s) + 1); /* start */
806 lua_pushinteger(L, res - s); /* end */
807 return push_captures(&ms, NULL, 0) + 2;
808 }
809 else
810 return push_captures(&ms, s1, res);
811 }
812 } while (s1++ < ms.src_end && !anchor);
813 }
814 luaL_pushfail(L); /* not found */
815 return 1;
816}
817
818
819static int str_find (lua_State *L) {
820 return str_find_aux(L, 1);
821}
822
823
824static int str_match (lua_State *L) {
825 return str_find_aux(L, 0);
826}
827
828
829/* state for 'gmatch' */
830typedef struct GMatchState {
831 const char *src; /* current position */
832 const char *p; /* pattern */
833 const char *lastmatch; /* end of last match */
834 MatchState ms; /* match state */
835} GMatchState;
836
837
838static int gmatch_aux (lua_State *L) {
839 GMatchState *gm = (GMatchState *)lua_touserdata(L, lua_upvalueindex(3));
840 const char *src;
841 gm->ms.L = L;
842 for (src = gm->src; src <= gm->ms.src_end; src++) {
843 const char *e;
844 reprepstate(&gm->ms);
845 if ((e = match(&gm->ms, src, gm->p)) != NULL && e != gm->lastmatch) {
846 gm->src = gm->lastmatch = e;
847 return push_captures(&gm->ms, src, e);
848 }
849 }
850 return 0; /* not found */
851}
852
853
854static int gmatch (lua_State *L) {
855 size_t ls, lp;
856 const char *s = luaL_checklstring(L, 1, &ls);
857 const char *p = luaL_checklstring(L, 2, &lp);
858 size_t init = posrelatI(luaL_optinteger(L, 3, 1), ls) - 1;
859 GMatchState *gm;
860 lua_settop(L, 2); /* keep strings on closure to avoid being collected */
861 gm = (GMatchState *)lua_newuserdatauv(L, sizeof(GMatchState), 0);
862 if (init > ls) /* start after string's end? */
863 init = ls + 1; /* avoid overflows in 's + init' */
864 prepstate(&gm->ms, L, s, ls, p, lp);
865 gm->src = s + init; gm->p = p; gm->lastmatch = NULL;
866 lua_pushcclosure(L, gmatch_aux, 3);
867 return 1;
868}
869
870
871static void add_s (MatchState *ms, luaL_Buffer *b, const char *s,
872 const char *e) {
873 size_t l;
874 lua_State *L = ms->L;
875 const char *news = lua_tolstring(L, 3, &l);
876 const char *p;
877 while ((p = (char *)memchr(news, L_ESC, l)) != NULL) {
878 luaL_addlstring(b, news, p - news);
879 p++; /* skip ESC */
880 if (*p == L_ESC) /* '%%' */
881 luaL_addchar(b, *p);
882 else if (*p == '0') /* '%0' */
883 luaL_addlstring(b, s, e - s);
884 else if (isdigit(uchar(*p))) { /* '%n' */
885 const char *cap;
886 ptrdiff_t resl = get_onecapture(ms, *p - '1', s, e, &cap);
887 if (resl == CAP_POSITION)
888 luaL_addvalue(b); /* add position to accumulated result */
889 else
890 luaL_addlstring(b, cap, resl);
891 }
892 else
893 luaL_error(L, "invalid use of '%c' in replacement string", L_ESC);
894 l -= p + 1 - news;
895 news = p + 1;
896 }
897 luaL_addlstring(b, news, l);
898}
899
900
901/*
902** Add the replacement value to the string buffer 'b'.
903** Return true if the original string was changed. (Function calls and
904** table indexing resulting in nil or false do not change the subject.)
905*/
906static int add_value (MatchState *ms, luaL_Buffer *b, const char *s,
907 const char *e, int tr) {
908 lua_State *L = ms->L;
909 switch (tr) {
910 case LUA_TFUNCTION: { /* call the function */
911 int n;
912 lua_pushvalue(L, 3); /* push the function */
913 n = push_captures(ms, s, e); /* all captures as arguments */
914 lua_call(L, n, 1); /* call it */
915 break;
916 }
917 case LUA_TTABLE: { /* index the table */
918 push_onecapture(ms, 0, s, e); /* first capture is the index */
919 lua_gettable(L, 3);
920 break;
921 }
922 default: { /* LUA_TNUMBER or LUA_TSTRING */
923 add_s(ms, b, s, e); /* add value to the buffer */
924 return 1; /* something changed */
925 }
926 }
927 if (!lua_toboolean(L, -1)) { /* nil or false? */
928 lua_pop(L, 1); /* remove value */
929 luaL_addlstring(b, s, e - s); /* keep original text */
930 return 0; /* no changes */
931 }
932 else if (l_unlikely(!lua_isstring(L, -1)))
933 return luaL_error(L, "invalid replacement value (a %s)",
934 luaL_typename(L, -1));
935 else {
936 luaL_addvalue(b); /* add result to accumulator */
937 return 1; /* something changed */
938 }
939}
940
941
942static int str_gsub (lua_State *L) {
943 size_t srcl, lp;
944 const char *src = luaL_checklstring(L, 1, &srcl); /* subject */
945 const char *p = luaL_checklstring(L, 2, &lp); /* pattern */
946 const char *lastmatch = NULL; /* end of last match */
947 int tr = lua_type(L, 3); /* replacement type */
948 lua_Integer max_s = luaL_optinteger(L, 4, srcl + 1); /* max replacements */
949 int anchor = (*p == '^');
950 lua_Integer n = 0; /* replacement count */
951 int changed = 0; /* change flag */
952 MatchState ms;
953 luaL_Buffer b;
954 luaL_argexpected(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||
955 tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3,
956 "string/function/table");
957 luaL_buffinit(L, &b);
958 if (anchor) {
959 p++; lp--; /* skip anchor character */
960 }
961 prepstate(&ms, L, src, srcl, p, lp);
962 while (n < max_s) {
963 const char *e;
964 reprepstate(&ms); /* (re)prepare state for new match */
965 if ((e = match(&ms, src, p)) != NULL && e != lastmatch) { /* match? */
966 n++;
967 changed = add_value(&ms, &b, src, e, tr) | changed;
968 src = lastmatch = e;
969 }
970 else if (src < ms.src_end) /* otherwise, skip one character */
971 luaL_addchar(&b, *src++);
972 else break; /* end of subject */
973 if (anchor) break;
974 }
975 if (!changed) /* no changes? */
976 lua_pushvalue(L, 1); /* return original string */
977 else { /* something changed */
978 luaL_addlstring(&b, src, ms.src_end-src);
979 luaL_pushresult(&b); /* create and return new string */
980 }
981 lua_pushinteger(L, n); /* number of substitutions */
982 return 2;
983}
984
985/* }====================================================== */
986
987
988
989/*
990** {======================================================
991** STRING FORMAT
992** =======================================================
993*/
994
995#if !defined(lua_number2strx) /* { */
996
997/*
998** Hexadecimal floating-point formatter
999*/
1000
1001#define SIZELENMOD (sizeof(LUA_NUMBER_FRMLEN)/sizeof(char))
1002
1003
1004/*
1005** Number of bits that goes into the first digit. It can be any value
1006** between 1 and 4; the following definition tries to align the number
1007** to nibble boundaries by making what is left after that first digit a
1008** multiple of 4.
1009*/
1010#define L_NBFD ((l_floatatt(MANT_DIG) - 1)%4 + 1)
1011
1012
1013/*
1014** Add integer part of 'x' to buffer and return new 'x'
1015*/
1016static lua_Number adddigit (char *buff, int n, lua_Number x) {
1017 lua_Number dd = l_mathop(floor)(x); /* get integer part from 'x' */
1018 int d = (int)dd;
1019 buff[n] = (d < 10 ? d + '0' : d - 10 + 'a'); /* add to buffer */
1020 return x - dd; /* return what is left */
1021}
1022
1023
1024static int num2straux (char *buff, int sz, lua_Number x) {
1025 /* if 'inf' or 'NaN', format it like '%g' */
1026 if (x != x || x == (lua_Number)HUGE_VAL || x == -(lua_Number)HUGE_VAL)
1027 return l_sprintf(buff, sz, LUA_NUMBER_FMT, (LUAI_UACNUMBER)x);
1028 else if (x == 0) { /* can be -0... */
1029 /* create "0" or "-0" followed by exponent */
1030 return l_sprintf(buff, sz, LUA_NUMBER_FMT "x0p+0", (LUAI_UACNUMBER)x);
1031 }
1032 else {
1033 int e;
1034 lua_Number m = l_mathop(frexp)(x, &e); /* 'x' fraction and exponent */
1035 int n = 0; /* character count */
1036 if (m < 0) { /* is number negative? */
1037 buff[n++] = '-'; /* add sign */
1038 m = -m; /* make it positive */
1039 }
1040 buff[n++] = '0'; buff[n++] = 'x'; /* add "0x" */
1041 m = adddigit(buff, n++, m * (1 << L_NBFD)); /* add first digit */
1042 e -= L_NBFD; /* this digit goes before the radix point */
1043 if (m > 0) { /* more digits? */
1044 buff[n++] = lua_getlocaledecpoint(); /* add radix point */
1045 do { /* add as many digits as needed */
1046 m = adddigit(buff, n++, m * 16);
1047 } while (m > 0);
1048 }
1049 n += l_sprintf(buff + n, sz - n, "p%+d", e); /* add exponent */
1050 lua_assert(n < sz);
1051 return n;
1052 }
1053}
1054
1055
1056static int lua_number2strx (lua_State *L, char *buff, int sz,
1057 const char *fmt, lua_Number x) {
1058 int n = num2straux(buff, sz, x);
1059 if (fmt[SIZELENMOD] == 'A') {
1060 int i;
1061 for (i = 0; i < n; i++)
1062 buff[i] = toupper(uchar(buff[i]));
1063 }
1064 else if (l_unlikely(fmt[SIZELENMOD] != 'a'))
1065 return luaL_error(L, "modifiers for format '%%a'/'%%A' not implemented");
1066 return n;
1067}
1068
1069#endif /* } */
1070
1071
1072/*
1073** Maximum size for items formatted with '%f'. This size is produced
1074** by format('%.99f', -maxfloat), and is equal to 99 + 3 ('-', '.',
1075** and '\0') + number of decimal digits to represent maxfloat (which
1076** is maximum exponent + 1). (99+3+1, adding some extra, 110)
1077*/
1078#define MAX_ITEMF (110 + l_floatatt(MAX_10_EXP))
1079
1080
1081/*
1082** All formats except '%f' do not need that large limit. The other
1083** float formats use exponents, so that they fit in the 99 limit for
1084** significant digits; 's' for large strings and 'q' add items directly
1085** to the buffer; all integer formats also fit in the 99 limit. The
1086** worst case are floats: they may need 99 significant digits, plus
1087** '0x', '-', '.', 'e+XXXX', and '\0'. Adding some extra, 120.
1088*/
1089#define MAX_ITEM 120
1090
1091
1092/* valid flags in a format specification */
1093#if !defined(L_FMTFLAGSF)
1094
1095/* valid flags for a, A, e, E, f, F, g, and G conversions */
1096#define L_FMTFLAGSF "-+#0 "
1097
1098/* valid flags for o, x, and X conversions */
1099#define L_FMTFLAGSX "-#0"
1100
1101/* valid flags for d and i conversions */
1102#define L_FMTFLAGSI "-+0 "
1103
1104/* valid flags for u conversions */
1105#define L_FMTFLAGSU "-0"
1106
1107/* valid flags for c, p, and s conversions */
1108#define L_FMTFLAGSC "-"
1109
1110#endif
1111
1112
1113/*
1114** Maximum size of each format specification (such as "%-099.99d"):
1115** Initial '%', flags (up to 5), width (2), period, precision (2),
1116** length modifier (8), conversion specifier, and final '\0', plus some
1117** extra.
1118*/
1119#define MAX_FORMAT 32
1120
1121
1122static void addquoted (luaL_Buffer *b, const char *s, size_t len) {
1123 luaL_addchar(b, '"');
1124 while (len--) {
1125 if (*s == '"' || *s == '\\' || *s == '\n') {
1126 luaL_addchar(b, '\\');
1127 luaL_addchar(b, *s);
1128 }
1129 else if (iscntrl(uchar(*s))) {
1130 char buff[10];
1131 if (!isdigit(uchar(*(s+1))))
1132 l_sprintf(buff, sizeof(buff), "\\%d", (int)uchar(*s));
1133 else
1134 l_sprintf(buff, sizeof(buff), "\\%03d", (int)uchar(*s));
1135 luaL_addstring(b, buff);
1136 }
1137 else
1138 luaL_addchar(b, *s);
1139 s++;
1140 }
1141 luaL_addchar(b, '"');
1142}
1143
1144
1145/*
1146** Serialize a floating-point number in such a way that it can be
1147** scanned back by Lua. Use hexadecimal format for "common" numbers
1148** (to preserve precision); inf, -inf, and NaN are handled separately.
1149** (NaN cannot be expressed as a numeral, so we write '(0/0)' for it.)
1150*/
1151static int quotefloat (lua_State *L, char *buff, lua_Number n) {
1152 const char *s; /* for the fixed representations */
1153 if (n == (lua_Number)HUGE_VAL) /* inf? */
1154 s = "1e9999";
1155 else if (n == -(lua_Number)HUGE_VAL) /* -inf? */
1156 s = "-1e9999";
1157 else if (n != n) /* NaN? */
1158 s = "(0/0)";
1159 else { /* format number as hexadecimal */
1160 int nb = lua_number2strx(L, buff, MAX_ITEM,
1161 "%" LUA_NUMBER_FRMLEN "a", n);
1162 /* ensures that 'buff' string uses a dot as the radix character */
1163 if (memchr(buff, '.', nb) == NULL) { /* no dot? */
1164 char point = lua_getlocaledecpoint(); /* try locale point */
1165 char *ppoint = (char *)memchr(buff, point, nb);
1166 if (ppoint) *ppoint = '.'; /* change it to a dot */
1167 }
1168 return nb;
1169 }
1170 /* for the fixed representations */
1171 return l_sprintf(buff, MAX_ITEM, "%s", s);
1172}
1173
1174
1175static void addliteral (lua_State *L, luaL_Buffer *b, int arg) {
1176 switch (lua_type(L, arg)) {
1177 case LUA_TSTRING: {
1178 size_t len;
1179 const char *s = lua_tolstring(L, arg, &len);
1180 addquoted(b, s, len);
1181 break;
1182 }
1183 case LUA_TNUMBER: {
1184 char *buff = luaL_prepbuffsize(b, MAX_ITEM);
1185 int nb;
1186 if (!lua_isinteger(L, arg)) /* float? */
1187 nb = quotefloat(L, buff, lua_tonumber(L, arg));
1188 else { /* integers */
1189 lua_Integer n = lua_tointeger(L, arg);
1190 const char *format = (n == LUA_MININTEGER) /* corner case? */
1191 ? "0x%" LUA_INTEGER_FRMLEN "x" /* use hex */
1192 : LUA_INTEGER_FMT; /* else use default format */
1193 nb = l_sprintf(buff, MAX_ITEM, format, (LUAI_UACINT)n);
1194 }
1195 luaL_addsize(b, nb);
1196 break;
1197 }
1198 case LUA_TNIL: case LUA_TBOOLEAN: {
1199 luaL_tolstring(L, arg, NULL);
1200 luaL_addvalue(b);
1201 break;
1202 }
1203 default: {
1204 luaL_argerror(L, arg, "value has no literal form");
1205 }
1206 }
1207}
1208
1209
1210static const char *get2digits (const char *s) {
1211 if (isdigit(uchar(*s))) {
1212 s++;
1213 if (isdigit(uchar(*s))) s++; /* (2 digits at most) */
1214 }
1215 return s;
1216}
1217
1218
1219/*
1220** Check whether a conversion specification is valid. When called,
1221** first character in 'form' must be '%' and last character must
1222** be a valid conversion specifier. 'flags' are the accepted flags;
1223** 'precision' signals whether to accept a precision.
1224*/
1225static void checkformat (lua_State *L, const char *form, const char *flags,
1226 int precision) {
1227 const char *spec = form + 1; /* skip '%' */
1228 spec += strspn(spec, flags); /* skip flags */
1229 if (*spec != '0') { /* a width cannot start with '0' */
1230 spec = get2digits(spec); /* skip width */
1231 if (*spec == '.' && precision) {
1232 spec++;
1233 spec = get2digits(spec); /* skip precision */
1234 }
1235 }
1236 if (!isalpha(uchar(*spec))) /* did not go to the end? */
1237 luaL_error(L, "invalid conversion specification: '%s'", form);
1238}
1239
1240
1241/*
1242** Get a conversion specification and copy it to 'form'.
1243** Return the address of its last character.
1244*/
1245static const char *getformat (lua_State *L, const char *strfrmt,
1246 char *form) {
1247 /* spans flags, width, and precision ('0' is included as a flag) */
1248 size_t len = strspn(strfrmt, L_FMTFLAGSF "123456789.");
1249 len++; /* adds following character (should be the specifier) */
1250 /* still needs space for '%', '\0', plus a length modifier */
1251 if (len >= MAX_FORMAT - 10)
1252 luaL_error(L, "invalid format (too long)");
1253 *(form++) = '%';
1254 memcpy(form, strfrmt, len * sizeof(char));
1255 *(form + len) = '\0';
1256 return strfrmt + len - 1;
1257}
1258
1259
1260/*
1261** add length modifier into formats
1262*/
1263static void addlenmod (char *form, const char *lenmod) {
1264 size_t l = strlen(form);
1265 size_t lm = strlen(lenmod);
1266 char spec = form[l - 1];
1267 strcpy(form + l - 1, lenmod);
1268 form[l + lm - 1] = spec;
1269 form[l + lm] = '\0';
1270}
1271
1272
1273static int str_format (lua_State *L) {
1274 int top = lua_gettop(L);
1275 int arg = 1;
1276 size_t sfl;
1277 const char *strfrmt = luaL_checklstring(L, arg, &sfl);
1278 const char *strfrmt_end = strfrmt+sfl;
1279 const char *flags;
1280 luaL_Buffer b;
1281 luaL_buffinit(L, &b);
1282 while (strfrmt < strfrmt_end) {
1283 if (*strfrmt != L_ESC)
1284 luaL_addchar(&b, *strfrmt++);
1285 else if (*++strfrmt == L_ESC)
1286 luaL_addchar(&b, *strfrmt++); /* %% */
1287 else { /* format item */
1288 char form[MAX_FORMAT]; /* to store the format ('%...') */
1289 int maxitem = MAX_ITEM; /* maximum length for the result */
1290 char *buff = luaL_prepbuffsize(&b, maxitem); /* to put result */
1291 int nb = 0; /* number of bytes in result */
1292 if (++arg > top)
1293 return luaL_argerror(L, arg, "no value");
1294 strfrmt = getformat(L, strfrmt, form);
1295 switch (*strfrmt++) {
1296 case 'c': {
1297 checkformat(L, form, L_FMTFLAGSC, 0);
1298 nb = l_sprintf(buff, maxitem, form, (int)luaL_checkinteger(L, arg));
1299 break;
1300 }
1301 case 'd': case 'i':
1302 flags = L_FMTFLAGSI;
1303 goto intcase;
1304 case 'u':
1305 flags = L_FMTFLAGSU;
1306 goto intcase;
1307 case 'o': case 'x': case 'X':
1308 flags = L_FMTFLAGSX;
1309 intcase: {
1310 lua_Integer n = luaL_checkinteger(L, arg);
1311 checkformat(L, form, flags, 1);
1312 addlenmod(form, LUA_INTEGER_FRMLEN);
1313 nb = l_sprintf(buff, maxitem, form, (LUAI_UACINT)n);
1314 break;
1315 }
1316 case 'a': case 'A':
1317 checkformat(L, form, L_FMTFLAGSF, 1);
1318 addlenmod(form, LUA_NUMBER_FRMLEN);
1319 nb = lua_number2strx(L, buff, maxitem, form,
1320 luaL_checknumber(L, arg));
1321 break;
1322 case 'f':
1323 maxitem = MAX_ITEMF; /* extra space for '%f' */
1324 buff = luaL_prepbuffsize(&b, maxitem);
1325 /* FALLTHROUGH */
1326 case 'e': case 'E': case 'g': case 'G': {
1327 lua_Number n = luaL_checknumber(L, arg);
1328 checkformat(L, form, L_FMTFLAGSF, 1);
1329 addlenmod(form, LUA_NUMBER_FRMLEN);
1330 nb = l_sprintf(buff, maxitem, form, (LUAI_UACNUMBER)n);
1331 break;
1332 }
1333 case 'p': {
1334 const void *p = lua_topointer(L, arg);
1335 checkformat(L, form, L_FMTFLAGSC, 0);
1336 if (p == NULL) { /* avoid calling 'printf' with argument NULL */
1337 p = "(null)"; /* result */
1338 form[strlen(form) - 1] = 's'; /* format it as a string */
1339 }
1340 nb = l_sprintf(buff, maxitem, form, p);
1341 break;
1342 }
1343 case 'q': {
1344 if (form[2] != '\0') /* modifiers? */
1345 return luaL_error(L, "specifier '%%q' cannot have modifiers");
1346 addliteral(L, &b, arg);
1347 break;
1348 }
1349 case 's': {
1350 size_t l;
1351 const char *s = luaL_tolstring(L, arg, &l);
1352 if (form[2] == '\0') /* no modifiers? */
1353 luaL_addvalue(&b); /* keep entire string */
1354 else {
1355 luaL_argcheck(L, l == strlen(s), arg, "string contains zeros");
1356 checkformat(L, form, L_FMTFLAGSC, 1);
1357 if (strchr(form, '.') == NULL && l >= 100) {
1358 /* no precision and string is too long to be formatted */
1359 luaL_addvalue(&b); /* keep entire string */
1360 }
1361 else { /* format the string into 'buff' */
1362 nb = l_sprintf(buff, maxitem, form, s);
1363 lua_pop(L, 1); /* remove result from 'luaL_tolstring' */
1364 }
1365 }
1366 break;
1367 }
1368 default: { /* also treat cases 'pnLlh' */
1369 return luaL_error(L, "invalid conversion '%s' to 'format'", form);
1370 }
1371 }
1372 lua_assert(nb < maxitem);
1373 luaL_addsize(&b, nb);
1374 }
1375 }
1376 luaL_pushresult(&b);
1377 return 1;
1378}
1379
1380/* }====================================================== */
1381
1382
1383/*
1384** {======================================================
1385** PACK/UNPACK
1386** =======================================================
1387*/
1388
1389
1390/* value used for padding */
1391#if !defined(LUAL_PACKPADBYTE)
1392#define LUAL_PACKPADBYTE 0x00
1393#endif
1394
1395/* maximum size for the binary representation of an integer */
1396#define MAXINTSIZE 16
1397
1398/* number of bits in a character */
1399#define NB CHAR_BIT
1400
1401/* mask for one character (NB 1's) */
1402#define MC ((1 << NB) - 1)
1403
1404/* size of a lua_Integer */
1405#define SZINT ((int)sizeof(lua_Integer))
1406
1407
1408/* dummy union to get native endianness */
1409static const union {
1410 int dummy;
1411 char little; /* true iff machine is little endian */
1412} nativeendian = {1};
1413
1414
1415/*
1416** information to pack/unpack stuff
1417*/
1418typedef struct Header {
1419 lua_State *L;
1420 int islittle;
1421 int maxalign;
1422} Header;
1423
1424
1425/*
1426** options for pack/unpack
1427*/
1428typedef enum KOption {
1429 Kint, /* signed integers */
1430 Kuint, /* unsigned integers */
1431 Kfloat, /* single-precision floating-point numbers */
1432 Knumber, /* Lua "native" floating-point numbers */
1433 Kdouble, /* double-precision floating-point numbers */
1434 Kchar, /* fixed-length strings */
1435 Kstring, /* strings with prefixed length */
1436 Kzstr, /* zero-terminated strings */
1437 Kpadding, /* padding */
1438 Kpaddalign, /* padding for alignment */
1439 Knop /* no-op (configuration or spaces) */
1440} KOption;
1441
1442
1443/*
1444** Read an integer numeral from string 'fmt' or return 'df' if
1445** there is no numeral
1446*/
1447static int digit (int c) { return '0' <= c && c <= '9'; }
1448
1449static int getnum (const char **fmt, int df) {
1450 if (!digit(**fmt)) /* no number? */
1451 return df; /* return default value */
1452 else {
1453 int a = 0;
1454 do {
1455 a = a*10 + (*((*fmt)++) - '0');
1456 } while (digit(**fmt) && a <= ((int)MAXSIZE - 9)/10);
1457 return a;
1458 }
1459}
1460
1461
1462/*
1463** Read an integer numeral and raises an error if it is larger
1464** than the maximum size for integers.
1465*/
1466static int getnumlimit (Header *h, const char **fmt, int df) {
1467 int sz = getnum(fmt, df);
1468 if (l_unlikely(sz > MAXINTSIZE || sz <= 0))
1469 return luaL_error(h->L, "integral size (%d) out of limits [1,%d]",
1470 sz, MAXINTSIZE);
1471 return sz;
1472}
1473
1474
1475/*
1476** Initialize Header
1477*/
1478static void initheader (lua_State *L, Header *h) {
1479 h->L = L;
1480 h->islittle = nativeendian.little;
1481 h->maxalign = 1;
1482}
1483
1484
1485/*
1486** Read and classify next option. 'size' is filled with option's size.
1487*/
1488static KOption getoption (Header *h, const char **fmt, int *size) {
1489 /* dummy structure to get native alignment requirements */
1490 struct cD { char c; union { LUAI_MAXALIGN; } u; };
1491 int opt = *((*fmt)++);
1492 *size = 0; /* default */
1493 switch (opt) {
1494 case 'b': *size = sizeof(char); return Kint;
1495 case 'B': *size = sizeof(char); return Kuint;
1496 case 'h': *size = sizeof(short); return Kint;
1497 case 'H': *size = sizeof(short); return Kuint;
1498 case 'l': *size = sizeof(long); return Kint;
1499 case 'L': *size = sizeof(long); return Kuint;
1500 case 'j': *size = sizeof(lua_Integer); return Kint;
1501 case 'J': *size = sizeof(lua_Integer); return Kuint;
1502 case 'T': *size = sizeof(size_t); return Kuint;
1503 case 'f': *size = sizeof(float); return Kfloat;
1504 case 'n': *size = sizeof(lua_Number); return Knumber;
1505 case 'd': *size = sizeof(double); return Kdouble;
1506 case 'i': *size = getnumlimit(h, fmt, sizeof(int)); return Kint;
1507 case 'I': *size = getnumlimit(h, fmt, sizeof(int)); return Kuint;
1508 case 's': *size = getnumlimit(h, fmt, sizeof(size_t)); return Kstring;
1509 case 'c':
1510 *size = getnum(fmt, -1);
1511 if (l_unlikely(*size == -1))
1512 luaL_error(h->L, "missing size for format option 'c'");
1513 return Kchar;
1514 case 'z': return Kzstr;
1515 case 'x': *size = 1; return Kpadding;
1516 case 'X': return Kpaddalign;
1517 case ' ': break;
1518 case '<': h->islittle = 1; break;
1519 case '>': h->islittle = 0; break;
1520 case '=': h->islittle = nativeendian.little; break;
1521 case '!': {
1522 const int maxalign = offsetof(struct cD, u);
1523 h->maxalign = getnumlimit(h, fmt, maxalign);
1524 break;
1525 }
1526 default: luaL_error(h->L, "invalid format option '%c'", opt);
1527 }
1528 return Knop;
1529}
1530
1531
1532/*
1533** Read, classify, and fill other details about the next option.
1534** 'psize' is filled with option's size, 'notoalign' with its
1535** alignment requirements.
1536** Local variable 'size' gets the size to be aligned. (Kpadal option
1537** always gets its full alignment, other options are limited by
1538** the maximum alignment ('maxalign'). Kchar option needs no alignment
1539** despite its size.
1540*/
1541static KOption getdetails (Header *h, size_t totalsize,
1542 const char **fmt, int *psize, int *ntoalign) {
1543 KOption opt = getoption(h, fmt, psize);
1544 int align = *psize; /* usually, alignment follows size */
1545 if (opt == Kpaddalign) { /* 'X' gets alignment from following option */
1546 if (**fmt == '\0' || getoption(h, fmt, &align) == Kchar || align == 0)
1547 luaL_argerror(h->L, 1, "invalid next option for option 'X'");
1548 }
1549 if (align <= 1 || opt == Kchar) /* need no alignment? */
1550 *ntoalign = 0;
1551 else {
1552 if (align > h->maxalign) /* enforce maximum alignment */
1553 align = h->maxalign;
1554 if (l_unlikely((align & (align - 1)) != 0)) /* not a power of 2? */
1555 luaL_argerror(h->L, 1, "format asks for alignment not power of 2");
1556 *ntoalign = (align - (int)(totalsize & (align - 1))) & (align - 1);
1557 }
1558 return opt;
1559}
1560
1561
1562/*
1563** Pack integer 'n' with 'size' bytes and 'islittle' endianness.
1564** The final 'if' handles the case when 'size' is larger than
1565** the size of a Lua integer, correcting the extra sign-extension
1566** bytes if necessary (by default they would be zeros).
1567*/
1568static void packint (luaL_Buffer *b, lua_Unsigned n,
1569 int islittle, int size, int neg) {
1570 char *buff = luaL_prepbuffsize(b, size);
1571 int i;
1572 buff[islittle ? 0 : size - 1] = (char)(n & MC); /* first byte */
1573 for (i = 1; i < size; i++) {
1574 n >>= NB;
1575 buff[islittle ? i : size - 1 - i] = (char)(n & MC);
1576 }
1577 if (neg && size > SZINT) { /* negative number need sign extension? */
1578 for (i = SZINT; i < size; i++) /* correct extra bytes */
1579 buff[islittle ? i : size - 1 - i] = (char)MC;
1580 }
1581 luaL_addsize(b, size); /* add result to buffer */
1582}
1583
1584
1585/*
1586** Copy 'size' bytes from 'src' to 'dest', correcting endianness if
1587** given 'islittle' is different from native endianness.
1588*/
1589static void copywithendian (char *dest, const char *src,
1590 int size, int islittle) {
1591 if (islittle == nativeendian.little)
1592 memcpy(dest, src, size);
1593 else {
1594 dest += size - 1;
1595 while (size-- != 0)
1596 *(dest--) = *(src++);
1597 }
1598}
1599
1600
1601static int str_pack (lua_State *L) {
1602 luaL_Buffer b;
1603 Header h;
1604 const char *fmt = luaL_checkstring(L, 1); /* format string */
1605 int arg = 1; /* current argument to pack */
1606 size_t totalsize = 0; /* accumulate total size of result */
1607 initheader(L, &h);
1608 lua_pushnil(L); /* mark to separate arguments from string buffer */
1609 luaL_buffinit(L, &b);
1610 while (*fmt != '\0') {
1611 int size, ntoalign;
1612 KOption opt = getdetails(&h, totalsize, &fmt, &size, &ntoalign);
1613 totalsize += ntoalign + size;
1614 while (ntoalign-- > 0)
1615 luaL_addchar(&b, LUAL_PACKPADBYTE); /* fill alignment */
1616 arg++;
1617 switch (opt) {
1618 case Kint: { /* signed integers */
1619 lua_Integer n = luaL_checkinteger(L, arg);
1620 if (size < SZINT) { /* need overflow check? */
1621 lua_Integer lim = (lua_Integer)1 << ((size * NB) - 1);
1622 luaL_argcheck(L, -lim <= n && n < lim, arg, "integer overflow");
1623 }
1624 packint(&b, (lua_Unsigned)n, h.islittle, size, (n < 0));
1625 break;
1626 }
1627 case Kuint: { /* unsigned integers */
1628 lua_Integer n = luaL_checkinteger(L, arg);
1629 if (size < SZINT) /* need overflow check? */
1630 luaL_argcheck(L, (lua_Unsigned)n < ((lua_Unsigned)1 << (size * NB)),
1631 arg, "unsigned overflow");
1632 packint(&b, (lua_Unsigned)n, h.islittle, size, 0);
1633 break;
1634 }
1635 case Kfloat: { /* C float */
1636 float f = (float)luaL_checknumber(L, arg); /* get argument */
1637 char *buff = luaL_prepbuffsize(&b, sizeof(f));
1638 /* move 'f' to final result, correcting endianness if needed */
1639 copywithendian(buff, (char *)&f, sizeof(f), h.islittle);
1640 luaL_addsize(&b, size);
1641 break;
1642 }
1643 case Knumber: { /* Lua float */
1644 lua_Number f = luaL_checknumber(L, arg); /* get argument */
1645 char *buff = luaL_prepbuffsize(&b, sizeof(f));
1646 /* move 'f' to final result, correcting endianness if needed */
1647 copywithendian(buff, (char *)&f, sizeof(f), h.islittle);
1648 luaL_addsize(&b, size);
1649 break;
1650 }
1651 case Kdouble: { /* C double */
1652 double f = (double)luaL_checknumber(L, arg); /* get argument */
1653 char *buff = luaL_prepbuffsize(&b, sizeof(f));
1654 /* move 'f' to final result, correcting endianness if needed */
1655 copywithendian(buff, (char *)&f, sizeof(f), h.islittle);
1656 luaL_addsize(&b, size);
1657 break;
1658 }
1659 case Kchar: { /* fixed-size string */
1660 size_t len;
1661 const char *s = luaL_checklstring(L, arg, &len);
1662 luaL_argcheck(L, len <= (size_t)size, arg,
1663 "string longer than given size");
1664 luaL_addlstring(&b, s, len); /* add string */
1665 while (len++ < (size_t)size) /* pad extra space */
1666 luaL_addchar(&b, LUAL_PACKPADBYTE);
1667 break;
1668 }
1669 case Kstring: { /* strings with length count */
1670 size_t len;
1671 const char *s = luaL_checklstring(L, arg, &len);
1672 luaL_argcheck(L, size >= (int)sizeof(size_t) ||
1673 len < ((size_t)1 << (size * NB)),
1674 arg, "string length does not fit in given size");
1675 packint(&b, (lua_Unsigned)len, h.islittle, size, 0); /* pack length */
1676 luaL_addlstring(&b, s, len);
1677 totalsize += len;
1678 break;
1679 }
1680 case Kzstr: { /* zero-terminated string */
1681 size_t len;
1682 const char *s = luaL_checklstring(L, arg, &len);
1683 luaL_argcheck(L, strlen(s) == len, arg, "string contains zeros");
1684 luaL_addlstring(&b, s, len);
1685 luaL_addchar(&b, '\0'); /* add zero at the end */
1686 totalsize += len + 1;
1687 break;
1688 }
1689 case Kpadding: luaL_addchar(&b, LUAL_PACKPADBYTE); /* FALLTHROUGH */
1690 case Kpaddalign: case Knop:
1691 arg--; /* undo increment */
1692 break;
1693 }
1694 }
1695 luaL_pushresult(&b);
1696 return 1;
1697}
1698
1699
1700static int str_packsize (lua_State *L) {
1701 Header h;
1702 const char *fmt = luaL_checkstring(L, 1); /* format string */
1703 size_t totalsize = 0; /* accumulate total size of result */
1704 initheader(L, &h);
1705 while (*fmt != '\0') {
1706 int size, ntoalign;
1707 KOption opt = getdetails(&h, totalsize, &fmt, &size, &ntoalign);
1708 luaL_argcheck(L, opt != Kstring && opt != Kzstr, 1,
1709 "variable-length format");
1710 size += ntoalign; /* total space used by option */
1711 luaL_argcheck(L, totalsize <= MAXSIZE - size, 1,
1712 "format result too large");
1713 totalsize += size;
1714 }
1715 lua_pushinteger(L, (lua_Integer)totalsize);
1716 return 1;
1717}
1718
1719
1720/*
1721** Unpack an integer with 'size' bytes and 'islittle' endianness.
1722** If size is smaller than the size of a Lua integer and integer
1723** is signed, must do sign extension (propagating the sign to the
1724** higher bits); if size is larger than the size of a Lua integer,
1725** it must check the unread bytes to see whether they do not cause an
1726** overflow.
1727*/
1728static lua_Integer unpackint (lua_State *L, const char *str,
1729 int islittle, int size, int issigned) {
1730 lua_Unsigned res = 0;
1731 int i;
1732 int limit = (size <= SZINT) ? size : SZINT;
1733 for (i = limit - 1; i >= 0; i--) {
1734 res <<= NB;
1735 res |= (lua_Unsigned)(unsigned char)str[islittle ? i : size - 1 - i];
1736 }
1737 if (size < SZINT) { /* real size smaller than lua_Integer? */
1738 if (issigned) { /* needs sign extension? */
1739 lua_Unsigned mask = (lua_Unsigned)1 << (size*NB - 1);
1740 res = ((res ^ mask) - mask); /* do sign extension */
1741 }
1742 }
1743 else if (size > SZINT) { /* must check unread bytes */
1744 int mask = (!issigned || (lua_Integer)res >= 0) ? 0 : MC;
1745 for (i = limit; i < size; i++) {
1746 if (l_unlikely((unsigned char)str[islittle ? i : size - 1 - i] != mask))
1747 luaL_error(L, "%d-byte integer does not fit into Lua Integer", size);
1748 }
1749 }
1750 return (lua_Integer)res;
1751}
1752
1753
1754static int str_unpack (lua_State *L) {
1755 Header h;
1756 const char *fmt = luaL_checkstring(L, 1);
1757 size_t ld;
1758 const char *data = luaL_checklstring(L, 2, &ld);
1759 size_t pos = posrelatI(luaL_optinteger(L, 3, 1), ld) - 1;
1760 int n = 0; /* number of results */
1761 luaL_argcheck(L, pos <= ld, 3, "initial position out of string");
1762 initheader(L, &h);
1763 while (*fmt != '\0') {
1764 int size, ntoalign;
1765 KOption opt = getdetails(&h, pos, &fmt, &size, &ntoalign);
1766 luaL_argcheck(L, (size_t)ntoalign + size <= ld - pos, 2,
1767 "data string too short");
1768 pos += ntoalign; /* skip alignment */
1769 /* stack space for item + next position */
1770 luaL_checkstack(L, 2, "too many results");
1771 n++;
1772 switch (opt) {
1773 case Kint:
1774 case Kuint: {
1775 lua_Integer res = unpackint(L, data + pos, h.islittle, size,
1776 (opt == Kint));
1777 lua_pushinteger(L, res);
1778 break;
1779 }
1780 case Kfloat: {
1781 float f;
1782 copywithendian((char *)&f, data + pos, sizeof(f), h.islittle);
1783 lua_pushnumber(L, (lua_Number)f);
1784 break;
1785 }
1786 case Knumber: {
1787 lua_Number f;
1788 copywithendian((char *)&f, data + pos, sizeof(f), h.islittle);
1789 lua_pushnumber(L, f);
1790 break;
1791 }
1792 case Kdouble: {
1793 double f;
1794 copywithendian((char *)&f, data + pos, sizeof(f), h.islittle);
1795 lua_pushnumber(L, (lua_Number)f);
1796 break;
1797 }
1798 case Kchar: {
1799 lua_pushlstring(L, data + pos, size);
1800 break;
1801 }
1802 case Kstring: {
1803 size_t len = (size_t)unpackint(L, data + pos, h.islittle, size, 0);
1804 luaL_argcheck(L, len <= ld - pos - size, 2, "data string too short");
1805 lua_pushlstring(L, data + pos + size, len);
1806 pos += len; /* skip string */
1807 break;
1808 }
1809 case Kzstr: {
1810 size_t len = strlen(data + pos);
1811 luaL_argcheck(L, pos + len < ld, 2,
1812 "unfinished string for format 'z'");
1813 lua_pushlstring(L, data + pos, len);
1814 pos += len + 1; /* skip string plus final '\0' */
1815 break;
1816 }
1817 case Kpaddalign: case Kpadding: case Knop:
1818 n--; /* undo increment */
1819 break;
1820 }
1821 pos += size;
1822 }
1823 lua_pushinteger(L, pos + 1); /* next position */
1824 return n + 1;
1825}
1826
1827/* }====================================================== */
1828
1829
1830static const luaL_Reg strlib[] = {
1831 {"byte", str_byte},
1832 {"char", str_char},
1833 {"dump", str_dump},
1834 {"find", str_find},
1835 {"format", str_format},
1836 {"gmatch", gmatch},
1837 {"gsub", str_gsub},
1838 {"len", str_len},
1839 {"lower", str_lower},
1840 {"match", str_match},
1841 {"rep", str_rep},
1842 {"reverse", str_reverse},
1843 {"sub", str_sub},
1844 {"upper", str_upper},
1845 {"pack", str_pack},
1846 {"packsize", str_packsize},
1847 {"unpack", str_unpack},
1848 {NULL, NULL}
1849};
1850
1851
1852static void createmetatable (lua_State *L) {
1853 /* table to be metatable for strings */
1854 luaL_newlibtable(L, stringmetamethods);
1855 luaL_setfuncs(L, stringmetamethods, 0);
1856 lua_pushliteral(L, ""); /* dummy string */
1857 lua_pushvalue(L, -2); /* copy table */
1858 lua_setmetatable(L, -2); /* set table as metatable for strings */
1859 lua_pop(L, 1); /* pop dummy string */
1860 lua_pushvalue(L, -2); /* get string library */
1861 lua_setfield(L, -2, "__index"); /* metatable.__index = string */
1862 lua_pop(L, 1); /* pop metatable */
1863}
1864
1865
1866/*
1867** Open string library
1868*/
1869LUAMOD_API int luaopen_string (lua_State *L) {
1870 luaL_newlib(L, strlib);
1871 createmetatable(L);
1872 return 1;
1873}
1874