GCC Code Coverage Report

Line	Branch	Decision	Exec	Source
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
55			✗	static 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				*/
71			✗	static 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				*/
87			✗	static 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
100			✗	static 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
112			✗	static 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
124			✗	static 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
137			✗	static 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
150			✗	static 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
177			✗	static 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
195			✗	static 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				*/
216				struct str_Writer {
217				int init; /* true iff buffer has been initialized */
218				luaL_Buffer B;
219				};
220
221
222			✗	static 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
233			✗	static 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
257				static const luaL_Reg stringmetamethods[] = {
258				{"__index", NULL}, /* placeholder */
259				{NULL, NULL}
260				};
261
262				#else /* }{ */
263
264			✗	static 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
277			✗	static 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
288			✗	static 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
297			✗	static int arith_add (lua_State *L) {
298			✗	return arith(L, LUA_OPADD, "__add");
299				}
300
301			✗	static int arith_sub (lua_State *L) {
302			✗	return arith(L, LUA_OPSUB, "__sub");
303				}
304
305			✗	static int arith_mul (lua_State *L) {
306			✗	return arith(L, LUA_OPMUL, "__mul");
307				}
308
309			✗	static int arith_mod (lua_State *L) {
310			✗	return arith(L, LUA_OPMOD, "__mod");
311				}
312
313			✗	static int arith_pow (lua_State *L) {
314			✗	return arith(L, LUA_OPPOW, "__pow");
315				}
316
317			✗	static int arith_div (lua_State *L) {
318			✗	return arith(L, LUA_OPDIV, "__div");
319				}
320
321			✗	static int arith_idiv (lua_State *L) {
322			✗	return arith(L, LUA_OPIDIV, "__idiv");
323				}
324
325			✗	static int arith_unm (lua_State *L) {
326			✗	return arith(L, LUA_OPUNM, "__unm");
327				}
328
329
330				static 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
358				typedef 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 */
373				static 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
386			✗	static 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
395			✗	static 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
403			✗	static 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
427			✗	static 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
447			✗	static 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
470			✗	static 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
486			✗	static 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
506			✗	static 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
521			✗	static 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
534			✗	static 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
548			✗	static 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
559			✗	static 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
570			✗	static 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
673			✗	static 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				*/
702			✗	static 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				*/
725			✗	static 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
735			✗	static 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 */
746			✗	static 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
757			✗	static 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
767			✗	static void reprepstate (MatchState *ms) {
768			✗	ms->level = 0;
769				lua_assert(ms->matchdepth == MAXCCALLS);
770			✗	}
771
772
773			✗	static 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
819			✗	static int str_find (lua_State *L) {
820			✗	return str_find_aux(L, 1);
821				}
822
823
824			✗	static int str_match (lua_State *L) {
825			✗	return str_find_aux(L, 0);
826				}
827
828
829				/* state for 'gmatch' */
830				typedef 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
838			✗	static 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
854			✗	static 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
871			✗	static 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				*/
906			✗	static 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
942			✗	static 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				*/
1016				static 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
1024				static 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
1056				static 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
1122			✗	static 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				*/
1151			✗	static 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
1175			✗	static 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
1210			✗	static 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				*/
1225			✗	static 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				*/
1245			✗	static 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				*/
1263			✗	static 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
1273			✗	static 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 */
1409				static 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				*/
1418				typedef struct Header {
1419				lua_State *L;
1420				int islittle;
1421				int maxalign;
1422				} Header;
1423
1424
1425				/*
1426				** options for pack/unpack
1427				*/
1428				typedef 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				*/
1447			✗	static int digit (int c) { return '0' <= c && c <= '9'; }
1448
1449			✗	static 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				*/
1466			✗	static 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				*/
1478			✗	static 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				*/
1488			✗	static 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				*/
1541			✗	static 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				*/
1568			✗	static 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				*/
1589			✗	static 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
1601			✗	static 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
1700			✗	static 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				*/
1728			✗	static 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
1754			✗	static 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
1830				static 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
1852			✗	static 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				*/
1869			✗	LUAMOD_API int luaopen_string (lua_State *L) {
1870			✗	luaL_newlib(L, strlib);
1871			✗	createmetatable(L);
1872			✗	return 1;
1873				}
1874
1875