root/src/lua/src/lstrlib.c

Revision 22d1941d0ca5ba7027cdfa51ce34bd1d8fb1931e, 22.9 kB (checked in by Theo Schlossnagle <jesus@omniti.com>, 10 years ago)

take the version out... it is what it is

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1 /*
2 ** $Id: lstrlib.c,v 1.132.1.3 2007/12/28 15:32:23 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
28 static 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
36 static 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
42 static 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
56 static 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
67 static 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
80 static 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
92 static 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
105 static 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
124 static 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
139 static 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
146 static 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
169 typedef 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
185 static 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
193 static 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
201 static 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
225 static 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
244 static 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
267 static 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
277 static const char *match (MatchState *ms, const char *s, const char *p);
278
279
280 static 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
300 static 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
315 static 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
328 static 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
342 static 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
353 static 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
364 static 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
443 static 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
465 static 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
484 static 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
494 static 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
537 static int str_find (lua_State *L) {
538   return str_find_aux(L, 1);
539 }
540
541
542 static int str_match (lua_State *L) {
543   return str_find_aux(L, 0);
544 }
545
546
547 static 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
573 static 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
583 static 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
589 static 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
611 static 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   }
633   if (!lua_toboolean(L, -1)) {  /* nil or false? */
634     lua_pop(L, 1);
635     lua_pushlstring(L, s, e - s);  /* keep original text */
636   }
637   else if (!lua_isstring(L, -1))
638     luaL_error(L, "invalid replacement value (a %s)", luaL_typename(L, -1));
639   luaL_addvalue(b);  /* add result to accumulator */
640 }
641
642
643 static int str_gsub (lua_State *L) {
644   size_t srcl;
645   const char *src = luaL_checklstring(L, 1, &srcl);
646   const char *p = luaL_checkstring(L, 2);
647   int  tr = lua_type(L, 3);
648   int max_s = luaL_optint(L, 4, srcl+1);
649   int anchor = (*p == '^') ? (p++, 1) : 0;
650   int n = 0;
651   MatchState ms;
652   luaL_Buffer b;
653   luaL_argcheck(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||
654                    tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3,
655                       "string/function/table expected");
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_ITEM        512
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
695 static 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
724 static 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
746 static 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
755 static 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
824 static 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
844 static 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 */
859 LUALIB_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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