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Root/lua/lstrlib.cc

1/*
2** $Id: lstrlib.c,v 1.132a 2006/04/26 20:41:19 roberto Exp $
3** Standard library for string operations and pattern-matching
4** See Copyright Notice in lua.h
5*/
6
7
8#include <ctype.h>
9#include <stddef.h>
10#include <stdio.h>
11#include <stdlib.h>
12#include <string.h>
13
14#define lstrlib_c
15#define LUA_LIB
16
17#include "lua.h"
18
19#include "lauxlib.h"
20#include "lualib.h"
21
22
23/* macro to `unsign' a character */
24#define uchar(c) ((unsigned char)(c))
25
26
27
28static int str_len (lua_State *L) {
29 size_t l;
30 luaL_checklstring(L, 1, &l);
31 lua_pushinteger(L, l);
32 return 1;
33}
34
35
36static ptrdiff_t posrelat (ptrdiff_t pos, size_t len) {
37 /* relative string position: negative means back from end */
38 return (pos>=0) ? pos : (ptrdiff_t)len+pos+1;
39}
40
41
42static int str_sub (lua_State *L) {
43 size_t l;
44 const char *s = luaL_checklstring(L, 1, &l);
45 ptrdiff_t start = posrelat(luaL_checkinteger(L, 2), l);
46 ptrdiff_t end = posrelat(luaL_optinteger(L, 3, -1), l);
47 if (start < 1) start = 1;
48 if (end > (ptrdiff_t)l) end = (ptrdiff_t)l;
49 if (start <= end)
50 lua_pushlstring(L, s+start-1, end-start+1);
51 else lua_pushliteral(L, "");
52 return 1;
53}
54
55
56static int str_reverse (lua_State *L) {
57 size_t l;
58 luaL_Buffer b;
59 const char *s = luaL_checklstring(L, 1, &l);
60 luaL_buffinit(L, &b);
61 while (l--) luaL_addchar(&b, s[l]);
62 luaL_pushresult(&b);
63 return 1;
64}
65
66
67static int str_lower (lua_State *L) {
68 size_t l;
69 size_t i;
70 luaL_Buffer b;
71 const char *s = luaL_checklstring(L, 1, &l);
72 luaL_buffinit(L, &b);
73 for (i=0; i<l; i++)
74 luaL_addchar(&b, tolower(uchar(s[i])));
75 luaL_pushresult(&b);
76 return 1;
77}
78
79
80static int str_upper (lua_State *L) {
81 size_t l;
82 size_t i;
83 luaL_Buffer b;
84 const char *s = luaL_checklstring(L, 1, &l);
85 luaL_buffinit(L, &b);
86 for (i=0; i<l; i++)
87 luaL_addchar(&b, toupper(uchar(s[i])));
88 luaL_pushresult(&b);
89 return 1;
90}
91
92static int str_rep (lua_State *L) {
93 size_t l;
94 luaL_Buffer b;
95 const char *s = luaL_checklstring(L, 1, &l);
96 int n = luaL_checkint(L, 2);
97 luaL_buffinit(L, &b);
98 while (n-- > 0)
99 luaL_addlstring(&b, s, l);
100 luaL_pushresult(&b);
101 return 1;
102}
103
104
105static int str_byte (lua_State *L) {
106 size_t l;
107 const char *s = luaL_checklstring(L, 1, &l);
108 ptrdiff_t posi = posrelat(luaL_optinteger(L, 2, 1), l);
109 ptrdiff_t pose = posrelat(luaL_optinteger(L, 3, posi), l);
110 int n, i;
111 if (posi <= 0) posi = 1;
112 if ((size_t)pose > l) pose = l;
113 if (posi > pose) return 0; /* empty interval; return no values */
114 n = (int)(pose - posi + 1);
115 if (posi + n <= pose) /* overflow? */
116 luaL_error(L, "string slice too long");
117 luaL_checkstack(L, n, "string slice too long");
118 for (i=0; i<n; i++)
119 lua_pushinteger(L, uchar(s[posi+i-1]));
120 return n;
121}
122
123
124static int str_char (lua_State *L) {
125 int n = lua_gettop(L); /* number of arguments */
126 int i;
127 luaL_Buffer b;
128 luaL_buffinit(L, &b);
129 for (i=1; i<=n; i++) {
130 int c = luaL_checkint(L, i);
131 luaL_argcheck(L, uchar(c) == c, i, "invalid value");
132 luaL_addchar(&b, uchar(c));
133 }
134 luaL_pushresult(&b);
135 return 1;
136}
137
138
139static int writer (lua_State *L, const void* b, size_t size, void* B) {
140 (void)L;
141 luaL_addlstring((luaL_Buffer*) B, (const char *)b, size);
142 return 0;
143}
144
145
146static int str_dump (lua_State *L) {
147 luaL_Buffer b;
148 luaL_checktype(L, 1, LUA_TFUNCTION);
149 lua_settop(L, 1);
150 luaL_buffinit(L,&b);
151 if (lua_dump(L, writer, &b) != 0)
152 luaL_error(L, "unable to dump given function");
153 luaL_pushresult(&b);
154 return 1;
155}
156
157
158
159/*
160** {======================================================
161** PATTERN MATCHING
162** =======================================================
163*/
164
165
166#define CAP_UNFINISHED(-1)
167#define CAP_POSITION(-2)
168
169typedef struct MatchState {
170 const char *src_init; /* init of source string */
171 const char *src_end; /* end (`\0') of source string */
172 lua_State *L;
173 int level; /* total number of captures (finished or unfinished) */
174 struct {
175 const char *init;
176 ptrdiff_t len;
177 } capture[LUA_MAXCAPTURES];
178} MatchState;
179
180
181#define L_ESC'%'
182#define SPECIALS"^$*+?.([%-"
183
184
185static int check_capture (MatchState *ms, int l) {
186 l -= '1';
187 if (l < 0 || l >= ms->level || ms->capture[l].len == CAP_UNFINISHED)
188 return luaL_error(ms->L, "invalid capture index");
189 return l;
190}
191
192
193static int capture_to_close (MatchState *ms) {
194 int level = ms->level;
195 for (level--; level>=0; level--)
196 if (ms->capture[level].len == CAP_UNFINISHED) return level;
197 return luaL_error(ms->L, "invalid pattern capture");
198}
199
200
201static const char *classend (MatchState *ms, const char *p) {
202 switch (*p++) {
203 case L_ESC: {
204 if (*p == '\0')
205 luaL_error(ms->L, "malformed pattern (ends with " LUA_QL("%%") ")");
206 return p+1;
207 }
208 case '[': {
209 if (*p == '^') p++;
210 do { /* look for a `]' */
211 if (*p == '\0')
212 luaL_error(ms->L, "malformed pattern (missing " LUA_QL("]") ")");
213 if (*(p++) == L_ESC && *p != '\0')
214 p++; /* skip escapes (e.g. `%]') */
215 } while (*p != ']');
216 return p+1;
217 }
218 default: {
219 return p;
220 }
221 }
222}
223
224
225static int match_class (int c, int cl) {
226 int res;
227 switch (tolower(cl)) {
228 case 'a' : res = isalpha(c); break;
229 case 'c' : res = iscntrl(c); break;
230 case 'd' : res = isdigit(c); break;
231 case 'l' : res = islower(c); break;
232 case 'p' : res = ispunct(c); break;
233 case 's' : res = isspace(c); break;
234 case 'u' : res = isupper(c); break;
235 case 'w' : res = isalnum(c); break;
236 case 'x' : res = isxdigit(c); break;
237 case 'z' : res = (c == 0); break;
238 default: return (cl == c);
239 }
240 return (islower(cl) ? res : !res);
241}
242
243
244static int matchbracketclass (int c, const char *p, const char *ec) {
245 int sig = 1;
246 if (*(p+1) == '^') {
247 sig = 0;
248 p++; /* skip the `^' */
249 }
250 while (++p < ec) {
251 if (*p == L_ESC) {
252 p++;
253 if (match_class(c, uchar(*p)))
254 return sig;
255 }
256 else if ((*(p+1) == '-') && (p+2 < ec)) {
257 p+=2;
258 if (uchar(*(p-2)) <= c && c <= uchar(*p))
259 return sig;
260 }
261 else if (uchar(*p) == c) return sig;
262 }
263 return !sig;
264}
265
266
267static int singlematch (int c, const char *p, const char *ep) {
268 switch (*p) {
269 case '.': return 1; /* matches any char */
270 case L_ESC: return match_class(c, uchar(*(p+1)));
271 case '[': return matchbracketclass(c, p, ep-1);
272 default: return (uchar(*p) == c);
273 }
274}
275
276
277static const char *match (MatchState *ms, const char *s, const char *p);
278
279
280static const char *matchbalance (MatchState *ms, const char *s,
281 const char *p) {
282 if (*p == 0 || *(p+1) == 0)
283 luaL_error(ms->L, "unbalanced pattern");
284 if (*s != *p) return NULL;
285 else {
286 int b = *p;
287 int e = *(p+1);
288 int cont = 1;
289 while (++s < ms->src_end) {
290 if (*s == e) {
291 if (--cont == 0) return s+1;
292 }
293 else if (*s == b) cont++;
294 }
295 }
296 return NULL; /* string ends out of balance */
297}
298
299
300static const char *max_expand (MatchState *ms, const char *s,
301 const char *p, const char *ep) {
302 ptrdiff_t i = 0; /* counts maximum expand for item */
303 while ((s+i)<ms->src_end && singlematch(uchar(*(s+i)), p, ep))
304 i++;
305 /* keeps trying to match with the maximum repetitions */
306 while (i>=0) {
307 const char *res = match(ms, (s+i), ep+1);
308 if (res) return res;
309 i--; /* else didn't match; reduce 1 repetition to try again */
310 }
311 return NULL;
312}
313
314
315static const char *min_expand (MatchState *ms, const char *s,
316 const char *p, const char *ep) {
317 for (;;) {
318 const char *res = match(ms, s, ep+1);
319 if (res != NULL)
320 return res;
321 else if (s<ms->src_end && singlematch(uchar(*s), p, ep))
322 s++; /* try with one more repetition */
323 else return NULL;
324 }
325}
326
327
328static const char *start_capture (MatchState *ms, const char *s,
329 const char *p, int what) {
330 const char *res;
331 int level = ms->level;
332 if (level >= LUA_MAXCAPTURES) luaL_error(ms->L, "too many captures");
333 ms->capture[level].init = s;
334 ms->capture[level].len = what;
335 ms->level = level+1;
336 if ((res=match(ms, s, p)) == NULL) /* match failed? */
337 ms->level--; /* undo capture */
338 return res;
339}
340
341
342static const char *end_capture (MatchState *ms, const char *s,
343 const char *p) {
344 int l = capture_to_close(ms);
345 const char *res;
346 ms->capture[l].len = s - ms->capture[l].init; /* close capture */
347 if ((res = match(ms, s, p)) == NULL) /* match failed? */
348 ms->capture[l].len = CAP_UNFINISHED; /* undo capture */
349 return res;
350}
351
352
353static const char *match_capture (MatchState *ms, const char *s, int l) {
354 size_t len;
355 l = check_capture(ms, l);
356 len = ms->capture[l].len;
357 if ((size_t)(ms->src_end-s) >= len &&
358 memcmp(ms->capture[l].init, s, len) == 0)
359 return s+len;
360 else return NULL;
361}
362
363
364static const char *match (MatchState *ms, const char *s, const char *p) {
365 init: /* using goto's to optimize tail recursion */
366 switch (*p) {
367 case '(': { /* start capture */
368 if (*(p+1) == ')') /* position capture? */
369 return start_capture(ms, s, p+2, CAP_POSITION);
370 else
371 return start_capture(ms, s, p+1, CAP_UNFINISHED);
372 }
373 case ')': { /* end capture */
374 return end_capture(ms, s, p+1);
375 }
376 case L_ESC: {
377 switch (*(p+1)) {
378 case 'b': { /* balanced string? */
379 s = matchbalance(ms, s, p+2);
380 if (s == NULL) return NULL;
381 p+=4; goto init; /* else return match(ms, s, p+4); */
382 }
383 case 'f': { /* frontier? */
384 const char *ep; char previous;
385 p += 2;
386 if (*p != '[')
387 luaL_error(ms->L, "missing " LUA_QL("[") " after "
388 LUA_QL("%%f") " in pattern");
389 ep = classend(ms, p); /* points to what is next */
390 previous = (s == ms->src_init) ? '\0' : *(s-1);
391 if (matchbracketclass(uchar(previous), p, ep-1) ||
392 !matchbracketclass(uchar(*s), p, ep-1)) return NULL;
393 p=ep; goto init; /* else return match(ms, s, ep); */
394 }
395 default: {
396 if (isdigit(uchar(*(p+1)))) { /* capture results (%0-%9)? */
397 s = match_capture(ms, s, uchar(*(p+1)));
398 if (s == NULL) return NULL;
399 p+=2; goto init; /* else return match(ms, s, p+2) */
400 }
401 goto dflt; /* case default */
402 }
403 }
404 }
405 case '\0': { /* end of pattern */
406 return s; /* match succeeded */
407 }
408 case '$': {
409 if (*(p+1) == '\0') /* is the `$' the last char in pattern? */
410 return (s == ms->src_end) ? s : NULL; /* check end of string */
411 else goto dflt;
412 }
413 default: dflt: { /* it is a pattern item */
414 const char *ep = classend(ms, p); /* points to what is next */
415 int m = s<ms->src_end && singlematch(uchar(*s), p, ep);
416 switch (*ep) {
417 case '?': { /* optional */
418 const char *res;
419 if (m && ((res=match(ms, s+1, ep+1)) != NULL))
420 return res;
421 p=ep+1; goto init; /* else return match(ms, s, ep+1); */
422 }
423 case '*': { /* 0 or more repetitions */
424 return max_expand(ms, s, p, ep);
425 }
426 case '+': { /* 1 or more repetitions */
427 return (m ? max_expand(ms, s+1, p, ep) : NULL);
428 }
429 case '-': { /* 0 or more repetitions (minimum) */
430 return min_expand(ms, s, p, ep);
431 }
432 default: {
433 if (!m) return NULL;
434 s++; p=ep; goto init; /* else return match(ms, s+1, ep); */
435 }
436 }
437 }
438 }
439}
440
441
442
443static const char *lmemfind (const char *s1, size_t l1,
444 const char *s2, size_t l2) {
445 if (l2 == 0) return s1; /* empty strings are everywhere */
446 else if (l2 > l1) return NULL; /* avoids a negative `l1' */
447 else {
448 const char *init; /* to search for a `*s2' inside `s1' */
449 l2--; /* 1st char will be checked by `memchr' */
450 l1 = l1-l2; /* `s2' cannot be found after that */
451 while (l1 > 0 && (init = (const char *)memchr(s1, *s2, l1)) != NULL) {
452 init++; /* 1st char is already checked */
453 if (memcmp(init, s2+1, l2) == 0)
454 return init-1;
455 else { /* correct `l1' and `s1' to try again */
456 l1 -= init-s1;
457 s1 = init;
458 }
459 }
460 return NULL; /* not found */
461 }
462}
463
464
465static void push_onecapture (MatchState *ms, int i, const char *s,
466 const char *e) {
467 if (i >= ms->level) {
468 if (i == 0) /* ms->level == 0, too */
469 lua_pushlstring(ms->L, s, e - s); /* add whole match */
470 else
471 luaL_error(ms->L, "invalid capture index");
472 }
473 else {
474 ptrdiff_t l = ms->capture[i].len;
475 if (l == CAP_UNFINISHED) luaL_error(ms->L, "unfinished capture");
476 if (l == CAP_POSITION)
477 lua_pushinteger(ms->L, ms->capture[i].init - ms->src_init + 1);
478 else
479 lua_pushlstring(ms->L, ms->capture[i].init, l);
480 }
481}
482
483
484static int push_captures (MatchState *ms, const char *s, const char *e) {
485 int i;
486 int nlevels = (ms->level == 0 && s) ? 1 : ms->level;
487 luaL_checkstack(ms->L, nlevels, "too many captures");
488 for (i = 0; i < nlevels; i++)
489 push_onecapture(ms, i, s, e);
490 return nlevels; /* number of strings pushed */
491}
492
493
494static int str_find_aux (lua_State *L, int find) {
495 size_t l1, l2;
496 const char *s = luaL_checklstring(L, 1, &l1);
497 const char *p = luaL_checklstring(L, 2, &l2);
498 ptrdiff_t init = posrelat(luaL_optinteger(L, 3, 1), l1) - 1;
499 if (init < 0) init = 0;
500 else if ((size_t)(init) > l1) init = (ptrdiff_t)l1;
501 if (find && (lua_toboolean(L, 4) || /* explicit request? */
502 strpbrk(p, SPECIALS) == NULL)) { /* or no special characters? */
503 /* do a plain search */
504 const char *s2 = lmemfind(s+init, l1-init, p, l2);
505 if (s2) {
506 lua_pushinteger(L, s2-s+1);
507 lua_pushinteger(L, s2-s+l2);
508 return 2;
509 }
510 }
511 else {
512 MatchState ms;
513 int anchor = (*p == '^') ? (p++, 1) : 0;
514 const char *s1=s+init;
515 ms.L = L;
516 ms.src_init = s;
517 ms.src_end = s+l1;
518 do {
519 const char *res;
520 ms.level = 0;
521 if ((res=match(&ms, s1, p)) != NULL) {
522 if (find) {
523 lua_pushinteger(L, s1-s+1); /* start */
524 lua_pushinteger(L, res-s); /* end */
525 return push_captures(&ms, NULL, 0) + 2;
526 }
527 else
528 return push_captures(&ms, s1, res);
529 }
530 } while (s1++ < ms.src_end && !anchor);
531 }
532 lua_pushnil(L); /* not found */
533 return 1;
534}
535
536
537static int str_find (lua_State *L) {
538 return str_find_aux(L, 1);
539}
540
541
542static int str_match (lua_State *L) {
543 return str_find_aux(L, 0);
544}
545
546
547static int gmatch_aux (lua_State *L) {
548 MatchState ms;
549 size_t ls;
550 const char *s = lua_tolstring(L, lua_upvalueindex(1), &ls);
551 const char *p = lua_tostring(L, lua_upvalueindex(2));
552 const char *src;
553 ms.L = L;
554 ms.src_init = s;
555 ms.src_end = s+ls;
556 for (src = s + (size_t)lua_tointeger(L, lua_upvalueindex(3));
557 src <= ms.src_end;
558 src++) {
559 const char *e;
560 ms.level = 0;
561 if ((e = match(&ms, src, p)) != NULL) {
562 lua_Integer newstart = e-s;
563 if (e == src) newstart++; /* empty match? go at least one position */
564 lua_pushinteger(L, newstart);
565 lua_replace(L, lua_upvalueindex(3));
566 return push_captures(&ms, src, e);
567 }
568 }
569 return 0; /* not found */
570}
571
572
573static int gmatch (lua_State *L) {
574 luaL_checkstring(L, 1);
575 luaL_checkstring(L, 2);
576 lua_settop(L, 2);
577 lua_pushinteger(L, 0);
578 lua_pushcclosure(L, gmatch_aux, 3);
579 return 1;
580}
581
582
583static int gfind_nodef (lua_State *L) {
584 return luaL_error(L, LUA_QL("string.gfind") " was renamed to "
585 LUA_QL("string.gmatch"));
586}
587
588
589static void add_s (MatchState *ms, luaL_Buffer *b, const char *s,
590 const char *e) {
591 size_t l, i;
592 const char *news = lua_tolstring(ms->L, 3, &l);
593 for (i = 0; i < l; i++) {
594 if (news[i] != L_ESC)
595 luaL_addchar(b, news[i]);
596 else {
597 i++; /* skip ESC */
598 if (!isdigit(uchar(news[i])))
599 luaL_addchar(b, news[i]);
600 else if (news[i] == '0')
601 luaL_addlstring(b, s, e - s);
602 else {
603 push_onecapture(ms, news[i] - '1', s, e);
604 luaL_addvalue(b); /* add capture to accumulated result */
605 }
606 }
607 }
608}
609
610
611static void add_value (MatchState *ms, luaL_Buffer *b, const char *s,
612 const char *e) {
613 lua_State *L = ms->L;
614 switch (lua_type(L, 3)) {
615 case LUA_TNUMBER:
616 case LUA_TSTRING: {
617 add_s(ms, b, s, e);
618 return;
619 }
620 case LUA_TFUNCTION: {
621 int n;
622 lua_pushvalue(L, 3);
623 n = push_captures(ms, s, e);
624 lua_call(L, n, 1);
625 break;
626 }
627 case LUA_TTABLE: {
628 push_onecapture(ms, 0, s, e);
629 lua_gettable(L, 3);
630 break;
631 }
632 default: {
633 luaL_argerror(L, 3, "string/function/table expected");
634 return;
635 }
636 }
637 if (!lua_toboolean(L, -1)) { /* nil or false? */
638 lua_pop(L, 1);
639 lua_pushlstring(L, s, e - s); /* keep original text */
640 }
641 else if (!lua_isstring(L, -1))
642 luaL_error(L, "invalid replacement value (a %s)", luaL_typename(L, -1));
643 luaL_addvalue(b); /* add result to accumulator */
644}
645
646
647static int str_gsub (lua_State *L) {
648 size_t srcl;
649 const char *src = luaL_checklstring(L, 1, &srcl);
650 const char *p = luaL_checkstring(L, 2);
651 int max_s = luaL_optint(L, 4, srcl+1);
652 int anchor = (*p == '^') ? (p++, 1) : 0;
653 int n = 0;
654 MatchState ms;
655 luaL_Buffer b;
656 luaL_buffinit(L, &b);
657 ms.L = L;
658 ms.src_init = src;
659 ms.src_end = src+srcl;
660 while (n < max_s) {
661 const char *e;
662 ms.level = 0;
663 e = match(&ms, src, p);
664 if (e) {
665 n++;
666 add_value(&ms, &b, src, e);
667 }
668 if (e && e>src) /* non empty match? */
669 src = e; /* skip it */
670 else if (src < ms.src_end)
671 luaL_addchar(&b, *src++);
672 else break;
673 if (anchor) break;
674 }
675 luaL_addlstring(&b, src, ms.src_end-src);
676 luaL_pushresult(&b);
677 lua_pushinteger(L, n); /* number of substitutions */
678 return 2;
679}
680
681/* }====================================================== */
682
683
684/* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */
685#define MAX_ITEM512
686/* valid flags in a format specification */
687#define FLAGS"-+ #0"
688/*
689** maximum size of each format specification (such as '%-099.99d')
690** (+10 accounts for %99.99x plus margin of error)
691*/
692#define MAX_FORMAT(sizeof(FLAGS) + sizeof(LUA_INTFRMLEN) + 10)
693
694
695static void addquoted (lua_State *L, luaL_Buffer *b, int arg) {
696 size_t l;
697 const char *s = luaL_checklstring(L, arg, &l);
698 luaL_addchar(b, '"');
699 while (l--) {
700 switch (*s) {
701 case '"': case '\\': case '\n': {
702 luaL_addchar(b, '\\');
703 luaL_addchar(b, *s);
704 break;
705 }
706 case '\r': {
707 luaL_addlstring(b, "\\r", 2);
708 break;
709 }
710 case '\0': {
711 luaL_addlstring(b, "\\000", 4);
712 break;
713 }
714 default: {
715 luaL_addchar(b, *s);
716 break;
717 }
718 }
719 s++;
720 }
721 luaL_addchar(b, '"');
722}
723
724static const char *scanformat (lua_State *L, const char *strfrmt, char *form) {
725 const char *p = strfrmt;
726 while (*p != '\0' && strchr(FLAGS, *p) != NULL) p++; /* skip flags */
727 if ((size_t)(p - strfrmt) >= sizeof(FLAGS))
728 luaL_error(L, "invalid format (repeated flags)");
729 if (isdigit(uchar(*p))) p++; /* skip width */
730 if (isdigit(uchar(*p))) p++; /* (2 digits at most) */
731 if (*p == '.') {
732 p++;
733 if (isdigit(uchar(*p))) p++; /* skip precision */
734 if (isdigit(uchar(*p))) p++; /* (2 digits at most) */
735 }
736 if (isdigit(uchar(*p)))
737 luaL_error(L, "invalid format (width or precision too long)");
738 *(form++) = '%';
739 strncpy(form, strfrmt, p - strfrmt + 1);
740 form += p - strfrmt + 1;
741 *form = '\0';
742 return p;
743}
744
745
746static void addintlen (char *form) {
747 size_t l = strlen(form);
748 char spec = form[l - 1];
749 strcpy(form + l - 1, LUA_INTFRMLEN);
750 form[l + sizeof(LUA_INTFRMLEN) - 2] = spec;
751 form[l + sizeof(LUA_INTFRMLEN) - 1] = '\0';
752}
753
754
755static int str_format (lua_State *L) {
756 int arg = 1;
757 size_t sfl;
758 const char *strfrmt = luaL_checklstring(L, arg, &sfl);
759 const char *strfrmt_end = strfrmt+sfl;
760 luaL_Buffer b;
761 luaL_buffinit(L, &b);
762 while (strfrmt < strfrmt_end) {
763 if (*strfrmt != L_ESC)
764 luaL_addchar(&b, *strfrmt++);
765 else if (*++strfrmt == L_ESC)
766 luaL_addchar(&b, *strfrmt++); /* %% */
767 else { /* format item */
768 char form[MAX_FORMAT]; /* to store the format (`%...') */
769 char buff[MAX_ITEM]; /* to store the formatted item */
770 arg++;
771 strfrmt = scanformat(L, strfrmt, form);
772 switch (*strfrmt++) {
773 case 'c': {
774 sprintf(buff, form, (int)luaL_checknumber(L, arg));
775 break;
776 }
777 case 'd': case 'i': {
778 addintlen(form);
779 sprintf(buff, form, (LUA_INTFRM_T)luaL_checknumber(L, arg));
780 break;
781 }
782 case 'o': case 'u': case 'x': case 'X': {
783 addintlen(form);
784 sprintf(buff, form, (unsigned LUA_INTFRM_T)luaL_checknumber(L, arg));
785 break;
786 }
787 case 'e': case 'E': case 'f':
788 case 'g': case 'G': {
789 sprintf(buff, form, (double)luaL_checknumber(L, arg));
790 break;
791 }
792 case 'q': {
793 addquoted(L, &b, arg);
794 continue; /* skip the 'addsize' at the end */
795 }
796 case 's': {
797 size_t l;
798 const char *s = luaL_checklstring(L, arg, &l);
799 if (!strchr(form, '.') && l >= 100) {
800 /* no precision and string is too long to be formatted;
801 keep original string */
802 lua_pushvalue(L, arg);
803 luaL_addvalue(&b);
804 continue; /* skip the `addsize' at the end */
805 }
806 else {
807 sprintf(buff, form, s);
808 break;
809 }
810 }
811 default: { /* also treat cases `pnLlh' */
812 return luaL_error(L, "invalid option " LUA_QL("%%%c") " to "
813 LUA_QL("format"), *(strfrmt - 1));
814 }
815 }
816 luaL_addlstring(&b, buff, strlen(buff));
817 }
818 }
819 luaL_pushresult(&b);
820 return 1;
821}
822
823
824static const luaL_Reg strlib[] = {
825 {"byte", str_byte},
826 {"char", str_char},
827 {"dump", str_dump},
828 {"find", str_find},
829 {"format", str_format},
830 {"gfind", gfind_nodef},
831 {"gmatch", gmatch},
832 {"gsub", str_gsub},
833 {"len", str_len},
834 {"lower", str_lower},
835 {"match", str_match},
836 {"rep", str_rep},
837 {"reverse", str_reverse},
838 {"sub", str_sub},
839 {"upper", str_upper},
840 {NULL, NULL}
841};
842
843
844static void createmetatable (lua_State *L) {
845 lua_createtable(L, 0, 1); /* create metatable for strings */
846 lua_pushliteral(L, ""); /* dummy string */
847 lua_pushvalue(L, -2);
848 lua_setmetatable(L, -2); /* set string metatable */
849 lua_pop(L, 1); /* pop dummy string */
850 lua_pushvalue(L, -2); /* string library... */
851 lua_setfield(L, -2, "__index"); /* ...is the __index metamethod */
852 lua_pop(L, 1); /* pop metatable */
853}
854
855
856/*
857** Open string library
858*/
859LUALIB_API int luaopen_string (lua_State *L) {
860 luaL_register(L, LUA_STRLIBNAME, strlib);
861#if defined(LUA_COMPAT_GFIND)
862 lua_getfield(L, -1, "gmatch");
863 lua_setfield(L, -2, "gfind");
864#endif
865 createmetatable(L);
866 return 1;
867}
868

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