1/*
2** $Id: lstrlib.c,v 1.178.1.1 2013/04/12 18:48:47 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/*
24** maximum number of captures that a pattern can do during
25** pattern-matching. This limit is arbitrary.
26*/
27#if !defined(LUA_MAXCAPTURES)
28#define LUA_MAXCAPTURES   32
29#endif
30
31
32/* macro to `unsign' a character */
33#define uchar(c)  ((unsigned char)(c))
34
35
36
37static int str_len (lua_State *L) {
38  size_t l;
39  luaL_checklstring(L, 1, &l);
40  lua_pushinteger(L, (lua_Integer)l);
41  return 1;
42}
43
44
45/* translate a relative string position: negative means back from end */
46static size_t posrelat (ptrdiff_t pos, size_t len) {
47  if (pos >= 0) return (size_t)pos;
48  else if (0u - (size_t)pos > len) return 0;
49  else return len - ((size_t)-pos) + 1;
50}
51
52
53static int str_sub (lua_State *L) {
54  size_t l;
55  const char *s = luaL_checklstring(L, 1, &l);
56  size_t start = posrelat(luaL_checkinteger(L, 2), l);
57  size_t end = posrelat(luaL_optinteger(L, 3, -1), l);
58  if (start < 1) start = 1;
59  if (end > l) end = l;
60  if (start <= end)
61    lua_pushlstring(L, s + start - 1, end - start + 1);
62  else lua_pushliteral(L, "");
63  return 1;
64}
65
66
67static int str_reverse (lua_State *L) {
68  size_t l, i;
69  luaL_Buffer b;
70  const char *s = luaL_checklstring(L, 1, &l);
71  char *p = luaL_buffinitsize(L, &b, l);
72  for (i = 0; i < l; i++)
73    p[i] = s[l - i - 1];
74  luaL_pushresultsize(&b, l);
75  return 1;
76}
77
78
79static int str_lower (lua_State *L) {
80  size_t l;
81  size_t i;
82  luaL_Buffer b;
83  const char *s = luaL_checklstring(L, 1, &l);
84  char *p = luaL_buffinitsize(L, &b, l);
85  for (i=0; i<l; i++)
86    p[i] = tolower(uchar(s[i]));
87  luaL_pushresultsize(&b, l);
88  return 1;
89}
90
91
92static int str_upper (lua_State *L) {
93  size_t l;
94  size_t i;
95  luaL_Buffer b;
96  const char *s = luaL_checklstring(L, 1, &l);
97  char *p = luaL_buffinitsize(L, &b, l);
98  for (i=0; i<l; i++)
99    p[i] = toupper(uchar(s[i]));
100  luaL_pushresultsize(&b, l);
101  return 1;
102}
103
104
105/* reasonable limit to avoid arithmetic overflow */
106#define MAXSIZE   ((~(size_t)0) >> 1)
107
108static int str_rep (lua_State *L) {
109  size_t l, lsep;
110  const char *s = luaL_checklstring(L, 1, &l);
111  int n = luaL_checkint(L, 2);
112  const char *sep = luaL_optlstring(L, 3, "", &lsep);
113  if (n <= 0) lua_pushliteral(L, "");
114  else if (l + lsep < l || l + lsep >= MAXSIZE / n)  /* may overflow? */
115    return luaL_error(L, "resulting string too large");
116  else {
117    size_t totallen = n * l + (n - 1) * lsep;
118    luaL_Buffer b;
119    char *p = luaL_buffinitsize(L, &b, totallen);
120    while (n-- > 1) {  /* first n-1 copies (followed by separator) */
121      memcpy(p, s, l * sizeof(char)); p += l;
122      if (lsep > 0) {  /* avoid empty 'memcpy' (may be expensive) */
123        memcpy(p, sep, lsep * sizeof(char)); p += lsep;
124      }
125    }
126    memcpy(p, s, l * sizeof(char));  /* last copy (not followed by separator) */
127    luaL_pushresultsize(&b, totallen);
128  }
129  return 1;
130}
131
132
133static int str_byte (lua_State *L) {
134  size_t l;
135  const char *s = luaL_checklstring(L, 1, &l);
136  size_t posi = posrelat(luaL_optinteger(L, 2, 1), l);
137  size_t pose = posrelat(luaL_optinteger(L, 3, posi), l);
138  int n, i;
139  if (posi < 1) posi = 1;
140  if (pose > l) pose = l;
141  if (posi > pose) return 0;  /* empty interval; return no values */
142  n = (int)(pose -  posi + 1);
143  if (posi + n <= pose)  /* (size_t -> int) overflow? */
144    return luaL_error(L, "string slice too long");
145  luaL_checkstack(L, n, "string slice too long");
146  for (i=0; i<n; i++)
147    lua_pushinteger(L, uchar(s[posi+i-1]));
148  return n;
149}
150
151
152static int str_char (lua_State *L) {
153  int n = lua_gettop(L);  /* number of arguments */
154  int i;
155  luaL_Buffer b;
156  char *p = luaL_buffinitsize(L, &b, n);
157  for (i=1; i<=n; i++) {
158    int c = luaL_checkint(L, i);
159    luaL_argcheck(L, uchar(c) == c, i, "value out of range");
160    p[i - 1] = uchar(c);
161  }
162  luaL_pushresultsize(&b, n);
163  return 1;
164}
165
166
167static int writer (lua_State *L, const void* b, size_t size, void* B) {
168  (void)L;
169  luaL_addlstring((luaL_Buffer*) B, (const char *)b, size);
170  return 0;
171}
172
173
174static int str_dump (lua_State *L) {
175  luaL_Buffer b;
176  luaL_checktype(L, 1, LUA_TFUNCTION);
177  lua_settop(L, 1);
178  luaL_buffinit(L,&b);
179  if (lua_dump(L, writer, &b) != 0)
180    return luaL_error(L, "unable to dump given function");
181  luaL_pushresult(&b);
182  return 1;
183}
184
185
186
187/*
188** {======================================================
189** PATTERN MATCHING
190** =======================================================
191*/
192
193
194#define CAP_UNFINISHED  (-1)
195#define CAP_POSITION  (-2)
196
197
198typedef struct MatchState {
199  int matchdepth;  /* control for recursive depth (to avoid C stack overflow) */
200  const char *src_init;  /* init of source string */
201  const char *src_end;  /* end ('\0') of source string */
202  const char *p_end;  /* end ('\0') of pattern */
203  lua_State *L;
204  int level;  /* total number of captures (finished or unfinished) */
205  struct {
206    const char *init;
207    ptrdiff_t len;
208  } capture[LUA_MAXCAPTURES];
209} MatchState;
210
211
212/* recursive function */
213static const char *match (MatchState *ms, const char *s, const char *p);
214
215
216/* maximum recursion depth for 'match' */
217#if !defined(MAXCCALLS)
218#define MAXCCALLS 200
219#endif
220
221
222#define L_ESC   '%'
223#define SPECIALS  "^$*+?.([%-"
224
225
226static int check_capture (MatchState *ms, int l) {
227  l -= '1';
228  if (l < 0 || l >= ms->level || ms->capture[l].len == CAP_UNFINISHED)
229    return luaL_error(ms->L, "invalid capture index %%%d", l + 1);
230  return l;
231}
232
233
234static int capture_to_close (MatchState *ms) {
235  int level = ms->level;
236  for (level--; level>=0; level--)
237    if (ms->capture[level].len == CAP_UNFINISHED) return level;
238  return luaL_error(ms->L, "invalid pattern capture");
239}
240
241
242static const char *classend (MatchState *ms, const char *p) {
243  switch (*p++) {
244    case L_ESC: {
245      if (p == ms->p_end)
246        luaL_error(ms->L, "malformed pattern (ends with " LUA_QL("%%") ")");
247      return p+1;
248    }
249    case '[': {
250      if (*p == '^') p++;
251      do {  /* look for a `]' */
252        if (p == ms->p_end)
253          luaL_error(ms->L, "malformed pattern (missing " LUA_QL("]") ")");
254        if (*(p++) == L_ESC && p < ms->p_end)
255          p++;  /* skip escapes (e.g. `%]') */
256      } while (*p != ']');
257      return p+1;
258    }
259    default: {
260      return p;
261    }
262  }
263}
264
265
266static int match_class (int c, int cl) {
267  int res;
268  switch (tolower(cl)) {
269    case 'a' : res = isalpha(c); break;
270    case 'c' : res = iscntrl(c); break;
271    case 'd' : res = isdigit(c); break;
272    case 'g' : res = isgraph(c); break;
273    case 'l' : res = islower(c); break;
274    case 'p' : res = ispunct(c); break;
275    case 's' : res = isspace(c); break;
276    case 'u' : res = isupper(c); break;
277    case 'w' : res = isalnum(c); break;
278    case 'x' : res = isxdigit(c); break;
279    case 'z' : res = (c == 0); break;  /* deprecated option */
280    default: return (cl == c);
281  }
282  return (islower(cl) ? res : !res);
283}
284
285
286static int matchbracketclass (int c, const char *p, const char *ec) {
287  int sig = 1;
288  if (*(p+1) == '^') {
289    sig = 0;
290    p++;  /* skip the `^' */
291  }
292  while (++p < ec) {
293    if (*p == L_ESC) {
294      p++;
295      if (match_class(c, uchar(*p)))
296        return sig;
297    }
298    else if ((*(p+1) == '-') && (p+2 < ec)) {
299      p+=2;
300      if (uchar(*(p-2)) <= c && c <= uchar(*p))
301        return sig;
302    }
303    else if (uchar(*p) == c) return sig;
304  }
305  return !sig;
306}
307
308
309static int singlematch (MatchState *ms, const char *s, const char *p,
310                        const char *ep) {
311  if (s >= ms->src_end)
312    return 0;
313  else {
314    int c = uchar(*s);
315    switch (*p) {
316      case '.': return 1;  /* matches any char */
317      case L_ESC: return match_class(c, uchar(*(p+1)));
318      case '[': return matchbracketclass(c, p, ep-1);
319      default:  return (uchar(*p) == c);
320    }
321  }
322}
323
324
325static const char *matchbalance (MatchState *ms, const char *s,
326                                   const char *p) {
327  if (p >= ms->p_end - 1)
328    luaL_error(ms->L, "malformed pattern "
329                      "(missing arguments to " LUA_QL("%%b") ")");
330  if (*s != *p) return NULL;
331  else {
332    int b = *p;
333    int e = *(p+1);
334    int cont = 1;
335    while (++s < ms->src_end) {
336      if (*s == e) {
337        if (--cont == 0) return s+1;
338      }
339      else if (*s == b) cont++;
340    }
341  }
342  return NULL;  /* string ends out of balance */
343}
344
345
346static const char *max_expand (MatchState *ms, const char *s,
347                                 const char *p, const char *ep) {
348  ptrdiff_t i = 0;  /* counts maximum expand for item */
349  while (singlematch(ms, s + i, p, ep))
350    i++;
351  /* keeps trying to match with the maximum repetitions */
352  while (i>=0) {
353    const char *res = match(ms, (s+i), ep+1);
354    if (res) return res;
355    i--;  /* else didn't match; reduce 1 repetition to try again */
356  }
357  return NULL;
358}
359
360
361static const char *min_expand (MatchState *ms, const char *s,
362                                 const char *p, const char *ep) {
363  for (;;) {
364    const char *res = match(ms, s, ep+1);
365    if (res != NULL)
366      return res;
367    else if (singlematch(ms, s, p, ep))
368      s++;  /* try with one more repetition */
369    else return NULL;
370  }
371}
372
373
374static const char *start_capture (MatchState *ms, const char *s,
375                                    const char *p, int what) {
376  const char *res;
377  int level = ms->level;
378  if (level >= LUA_MAXCAPTURES) luaL_error(ms->L, "too many captures");
379  ms->capture[level].init = s;
380  ms->capture[level].len = what;
381  ms->level = level+1;
382  if ((res=match(ms, s, p)) == NULL)  /* match failed? */
383    ms->level--;  /* undo capture */
384  return res;
385}
386
387
388static const char *end_capture (MatchState *ms, const char *s,
389                                  const char *p) {
390  int l = capture_to_close(ms);
391  const char *res;
392  ms->capture[l].len = s - ms->capture[l].init;  /* close capture */
393  if ((res = match(ms, s, p)) == NULL)  /* match failed? */
394    ms->capture[l].len = CAP_UNFINISHED;  /* undo capture */
395  return res;
396}
397
398
399static const char *match_capture (MatchState *ms, const char *s, int l) {
400  size_t len;
401  l = check_capture(ms, l);
402  len = ms->capture[l].len;
403  if ((size_t)(ms->src_end-s) >= len &&
404      memcmp(ms->capture[l].init, s, len) == 0)
405    return s+len;
406  else return NULL;
407}
408
409
410static const char *match (MatchState *ms, const char *s, const char *p) {
411  if (ms->matchdepth-- == 0)
412    luaL_error(ms->L, "pattern too complex");
413  init: /* using goto's to optimize tail recursion */
414  if (p != ms->p_end) {  /* end of pattern? */
415    switch (*p) {
416      case '(': {  /* start capture */
417        if (*(p + 1) == ')')  /* position capture? */
418          s = start_capture(ms, s, p + 2, CAP_POSITION);
419        else
420          s = start_capture(ms, s, p + 1, CAP_UNFINISHED);
421        break;
422      }
423      case ')': {  /* end capture */
424        s = end_capture(ms, s, p + 1);
425        break;
426      }
427      case '$': {
428        if ((p + 1) != ms->p_end)  /* is the `$' the last char in pattern? */
429          goto dflt;  /* no; go to default */
430        s = (s == ms->src_end) ? s : NULL;  /* check end of string */
431        break;
432      }
433      case L_ESC: {  /* escaped sequences not in the format class[*+?-]? */
434        switch (*(p + 1)) {
435          case 'b': {  /* balanced string? */
436            s = matchbalance(ms, s, p + 2);
437            if (s != NULL) {
438              p += 4; goto init;  /* return match(ms, s, p + 4); */
439            }  /* else fail (s == NULL) */
440            break;
441          }
442          case 'f': {  /* frontier? */
443            const char *ep; char previous;
444            p += 2;
445            if (*p != '[')
446              luaL_error(ms->L, "missing " LUA_QL("[") " after "
447                                 LUA_QL("%%f") " in pattern");
448            ep = classend(ms, p);  /* points to what is next */
449            previous = (s == ms->src_init) ? '\0' : *(s - 1);
450            if (!matchbracketclass(uchar(previous), p, ep - 1) &&
451               matchbracketclass(uchar(*s), p, ep - 1)) {
452              p = ep; goto init;  /* return match(ms, s, ep); */
453            }
454            s = NULL;  /* match failed */
455            break;
456          }
457          case '0': case '1': case '2': case '3':
458          case '4': case '5': case '6': case '7':
459          case '8': case '9': {  /* capture results (%0-%9)? */
460            s = match_capture(ms, s, uchar(*(p + 1)));
461            if (s != NULL) {
462              p += 2; goto init;  /* return match(ms, s, p + 2) */
463            }
464            break;
465          }
466          default: goto dflt;
467        }
468        break;
469      }
470      default: dflt: {  /* pattern class plus optional suffix */
471        const char *ep = classend(ms, p);  /* points to optional suffix */
472        /* does not match at least once? */
473        if (!singlematch(ms, s, p, ep)) {
474          if (*ep == '*' || *ep == '?' || *ep == '-') {  /* accept empty? */
475            p = ep + 1; goto init;  /* return match(ms, s, ep + 1); */
476          }
477          else  /* '+' or no suffix */
478            s = NULL;  /* fail */
479        }
480        else {  /* matched once */
481          switch (*ep) {  /* handle optional suffix */
482            case '?': {  /* optional */
483              const char *res;
484              if ((res = match(ms, s + 1, ep + 1)) != NULL)
485                s = res;
486              else {
487                p = ep + 1; goto init;  /* else return match(ms, s, ep + 1); */
488              }
489              break;
490            }
491            case '+':  /* 1 or more repetitions */
492              s++;  /* 1 match already done */
493              /* go through */
494            case '*':  /* 0 or more repetitions */
495              s = max_expand(ms, s, p, ep);
496              break;
497            case '-':  /* 0 or more repetitions (minimum) */
498              s = min_expand(ms, s, p, ep);
499              break;
500            default:  /* no suffix */
501              s++; p = ep; goto init;  /* return match(ms, s + 1, ep); */
502          }
503        }
504        break;
505      }
506    }
507  }
508  ms->matchdepth++;
509  return s;
510}
511
512
513
514static const char *lmemfind (const char *s1, size_t l1,
515                               const char *s2, size_t l2) {
516  if (l2 == 0) return s1;  /* empty strings are everywhere */
517  else if (l2 > l1) return NULL;  /* avoids a negative `l1' */
518  else {
519    const char *init;  /* to search for a `*s2' inside `s1' */
520    l2--;  /* 1st char will be checked by `memchr' */
521    l1 = l1-l2;  /* `s2' cannot be found after that */
522    while (l1 > 0 && (init = (const char *)memchr(s1, *s2, l1)) != NULL) {
523      init++;   /* 1st char is already checked */
524      if (memcmp(init, s2+1, l2) == 0)
525        return init-1;
526      else {  /* correct `l1' and `s1' to try again */
527        l1 -= init-s1;
528        s1 = init;
529      }
530    }
531    return NULL;  /* not found */
532  }
533}
534
535
536static void push_onecapture (MatchState *ms, int i, const char *s,
537                                                    const char *e) {
538  if (i >= ms->level) {
539    if (i == 0)  /* ms->level == 0, too */
540      lua_pushlstring(ms->L, s, e - s);  /* add whole match */
541    else
542      luaL_error(ms->L, "invalid capture index");
543  }
544  else {
545    ptrdiff_t l = ms->capture[i].len;
546    if (l == CAP_UNFINISHED) luaL_error(ms->L, "unfinished capture");
547    if (l == CAP_POSITION)
548      lua_pushinteger(ms->L, ms->capture[i].init - ms->src_init + 1);
549    else
550      lua_pushlstring(ms->L, ms->capture[i].init, l);
551  }
552}
553
554
555static int push_captures (MatchState *ms, const char *s, const char *e) {
556  int i;
557  int nlevels = (ms->level == 0 && s) ? 1 : ms->level;
558  luaL_checkstack(ms->L, nlevels, "too many captures");
559  for (i = 0; i < nlevels; i++)
560    push_onecapture(ms, i, s, e);
561  return nlevels;  /* number of strings pushed */
562}
563
564
565/* check whether pattern has no special characters */
566static int nospecials (const char *p, size_t l) {
567  size_t upto = 0;
568  do {
569    if (strpbrk(p + upto, SPECIALS))
570      return 0;  /* pattern has a special character */
571    upto += strlen(p + upto) + 1;  /* may have more after \0 */
572  } while (upto <= l);
573  return 1;  /* no special chars found */
574}
575
576
577static int str_find_aux (lua_State *L, int find) {
578  size_t ls, lp;
579  const char *s = luaL_checklstring(L, 1, &ls);
580  const char *p = luaL_checklstring(L, 2, &lp);
581  size_t init = posrelat(luaL_optinteger(L, 3, 1), ls);
582  if (init < 1) init = 1;
583  else if (init > ls + 1) {  /* start after string's end? */
584    lua_pushnil(L);  /* cannot find anything */
585    return 1;
586  }
587  /* explicit request or no special characters? */
588  if (find && (lua_toboolean(L, 4) || nospecials(p, lp))) {
589    /* do a plain search */
590    const char *s2 = lmemfind(s + init - 1, ls - init + 1, p, lp);
591    if (s2) {
592      lua_pushinteger(L, s2 - s + 1);
593      lua_pushinteger(L, s2 - s + lp);
594      return 2;
595    }
596  }
597  else {
598    MatchState ms;
599    const char *s1 = s + init - 1;
600    int anchor = (*p == '^');
601    if (anchor) {
602      p++; lp--;  /* skip anchor character */
603    }
604    ms.L = L;
605    ms.matchdepth = MAXCCALLS;
606    ms.src_init = s;
607    ms.src_end = s + ls;
608    ms.p_end = p + lp;
609    do {
610      const char *res;
611      ms.level = 0;
612      lua_assert(ms.matchdepth == MAXCCALLS);
613      if ((res=match(&ms, s1, p)) != NULL) {
614        if (find) {
615          lua_pushinteger(L, s1 - s + 1);  /* start */
616          lua_pushinteger(L, res - s);   /* end */
617          return push_captures(&ms, NULL, 0) + 2;
618        }
619        else
620          return push_captures(&ms, s1, res);
621      }
622    } while (s1++ < ms.src_end && !anchor);
623  }
624  lua_pushnil(L);  /* not found */
625  return 1;
626}
627
628
629static int str_find (lua_State *L) {
630  return str_find_aux(L, 1);
631}
632
633
634static int str_match (lua_State *L) {
635  return str_find_aux(L, 0);
636}
637
638
639static int gmatch_aux (lua_State *L) {
640  MatchState ms;
641  size_t ls, lp;
642  const char *s = lua_tolstring(L, lua_upvalueindex(1), &ls);
643  const char *p = lua_tolstring(L, lua_upvalueindex(2), &lp);
644  const char *src;
645  ms.L = L;
646  ms.matchdepth = MAXCCALLS;
647  ms.src_init = s;
648  ms.src_end = s+ls;
649  ms.p_end = p + lp;
650  for (src = s + (size_t)lua_tointeger(L, lua_upvalueindex(3));
651       src <= ms.src_end;
652       src++) {
653    const char *e;
654    ms.level = 0;
655    lua_assert(ms.matchdepth == MAXCCALLS);
656    if ((e = match(&ms, src, p)) != NULL) {
657      lua_Integer newstart = e-s;
658      if (e == src) newstart++;  /* empty match? go at least one position */
659      lua_pushinteger(L, newstart);
660      lua_replace(L, lua_upvalueindex(3));
661      return push_captures(&ms, src, e);
662    }
663  }
664  return 0;  /* not found */
665}
666
667
668static int gmatch (lua_State *L) {
669  luaL_checkstring(L, 1);
670  luaL_checkstring(L, 2);
671  lua_settop(L, 2);
672  lua_pushinteger(L, 0);
673  lua_pushcclosure(L, gmatch_aux, 3);
674  return 1;
675}
676
677
678static void add_s (MatchState *ms, luaL_Buffer *b, const char *s,
679                                                   const char *e) {
680  size_t l, i;
681  const char *news = lua_tolstring(ms->L, 3, &l);
682  for (i = 0; i < l; i++) {
683    if (news[i] != L_ESC)
684      luaL_addchar(b, news[i]);
685    else {
686      i++;  /* skip ESC */
687      if (!isdigit(uchar(news[i]))) {
688        if (news[i] != L_ESC)
689          luaL_error(ms->L, "invalid use of " LUA_QL("%c")
690                           " in replacement string", L_ESC);
691        luaL_addchar(b, news[i]);
692      }
693      else if (news[i] == '0')
694          luaL_addlstring(b, s, e - s);
695      else {
696        push_onecapture(ms, news[i] - '1', s, e);
697        luaL_addvalue(b);  /* add capture to accumulated result */
698      }
699    }
700  }
701}
702
703
704static void add_value (MatchState *ms, luaL_Buffer *b, const char *s,
705                                       const char *e, int tr) {
706  lua_State *L = ms->L;
707  switch (tr) {
708    case LUA_TFUNCTION: {
709      int n;
710      lua_pushvalue(L, 3);
711      n = push_captures(ms, s, e);
712      lua_call(L, n, 1);
713      break;
714    }
715    case LUA_TTABLE: {
716      push_onecapture(ms, 0, s, e);
717      lua_gettable(L, 3);
718      break;
719    }
720    default: {  /* LUA_TNUMBER or LUA_TSTRING */
721      add_s(ms, b, s, e);
722      return;
723    }
724  }
725  if (!lua_toboolean(L, -1)) {  /* nil or false? */
726    lua_pop(L, 1);
727    lua_pushlstring(L, s, e - s);  /* keep original text */
728  }
729  else if (!lua_isstring(L, -1))
730    luaL_error(L, "invalid replacement value (a %s)", luaL_typename(L, -1));
731  luaL_addvalue(b);  /* add result to accumulator */
732}
733
734
735static int str_gsub (lua_State *L) {
736  size_t srcl, lp;
737  const char *src = luaL_checklstring(L, 1, &srcl);
738  const char *p = luaL_checklstring(L, 2, &lp);
739  int tr = lua_type(L, 3);
740  size_t max_s = luaL_optinteger(L, 4, srcl+1);
741  int anchor = (*p == '^');
742  size_t n = 0;
743  MatchState ms;
744  luaL_Buffer b;
745  luaL_argcheck(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||
746                   tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3,
747                      "string/function/table expected");
748  luaL_buffinit(L, &b);
749  if (anchor) {
750    p++; lp--;  /* skip anchor character */
751  }
752  ms.L = L;
753  ms.matchdepth = MAXCCALLS;
754  ms.src_init = src;
755  ms.src_end = src+srcl;
756  ms.p_end = p + lp;
757  while (n < max_s) {
758    const char *e;
759    ms.level = 0;
760    lua_assert(ms.matchdepth == MAXCCALLS);
761    e = match(&ms, src, p);
762    if (e) {
763      n++;
764      add_value(&ms, &b, src, e, tr);
765    }
766    if (e && e>src) /* non empty match? */
767      src = e;  /* skip it */
768    else if (src < ms.src_end)
769      luaL_addchar(&b, *src++);
770    else break;
771    if (anchor) break;
772  }
773  luaL_addlstring(&b, src, ms.src_end-src);
774  luaL_pushresult(&b);
775  lua_pushinteger(L, n);  /* number of substitutions */
776  return 2;
777}
778
779/* }====================================================== */
780
781
782
783/*
784** {======================================================
785** STRING FORMAT
786** =======================================================
787*/
788
789/*
790** LUA_INTFRMLEN is the length modifier for integer conversions in
791** 'string.format'; LUA_INTFRM_T is the integer type corresponding to
792** the previous length
793*/
794#if !defined(LUA_INTFRMLEN) /* { */
795#if defined(LUA_USE_LONGLONG)
796
797#define LUA_INTFRMLEN   "ll"
798#define LUA_INTFRM_T    long long
799
800#else
801
802#define LUA_INTFRMLEN   "l"
803#define LUA_INTFRM_T    long
804
805#endif
806#endif        /* } */
807
808
809/*
810** LUA_FLTFRMLEN is the length modifier for float conversions in
811** 'string.format'; LUA_FLTFRM_T is the float type corresponding to
812** the previous length
813*/
814#if !defined(LUA_FLTFRMLEN)
815
816#define LUA_FLTFRMLEN   ""
817#define LUA_FLTFRM_T    double
818
819#endif
820
821
822/* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */
823#define MAX_ITEM  512
824/* valid flags in a format specification */
825#define FLAGS "-+ #0"
826/*
827** maximum size of each format specification (such as '%-099.99d')
828** (+10 accounts for %99.99x plus margin of error)
829*/
830#define MAX_FORMAT  (sizeof(FLAGS) + sizeof(LUA_INTFRMLEN) + 10)
831
832
833static void addquoted (lua_State *L, luaL_Buffer *b, int arg) {
834  size_t l;
835  const char *s = luaL_checklstring(L, arg, &l);
836  luaL_addchar(b, '"');
837  while (l--) {
838    if (*s == '"' || *s == '\\' || *s == '\n') {
839      luaL_addchar(b, '\\');
840      luaL_addchar(b, *s);
841    }
842    else if (*s == '\0' || iscntrl(uchar(*s))) {
843      char buff[10];
844      if (!isdigit(uchar(*(s+1))))
845        sprintf(buff, "\\%d", (int)uchar(*s));
846      else
847        sprintf(buff, "\\%03d", (int)uchar(*s));
848      luaL_addstring(b, buff);
849    }
850    else
851      luaL_addchar(b, *s);
852    s++;
853  }
854  luaL_addchar(b, '"');
855}
856
857static const char *scanformat (lua_State *L, const char *strfrmt, char *form) {
858  const char *p = strfrmt;
859  while (*p != '\0' && strchr(FLAGS, *p) != NULL) p++;  /* skip flags */
860  if ((size_t)(p - strfrmt) >= sizeof(FLAGS)/sizeof(char))
861    luaL_error(L, "invalid format (repeated flags)");
862  if (isdigit(uchar(*p))) p++;  /* skip width */
863  if (isdigit(uchar(*p))) p++;  /* (2 digits at most) */
864  if (*p == '.') {
865    p++;
866    if (isdigit(uchar(*p))) p++;  /* skip precision */
867    if (isdigit(uchar(*p))) p++;  /* (2 digits at most) */
868  }
869  if (isdigit(uchar(*p)))
870    luaL_error(L, "invalid format (width or precision too long)");
871  *(form++) = '%';
872  memcpy(form, strfrmt, (p - strfrmt + 1) * sizeof(char));
873  form += p - strfrmt + 1;
874  *form = '\0';
875  return p;
876}
877
878
879/*
880** add length modifier into formats
881*/
882static void addlenmod (char *form, const char *lenmod) {
883  size_t l = strlen(form);
884  size_t lm = strlen(lenmod);
885  char spec = form[l - 1];
886  strcpy(form + l - 1, lenmod);
887  form[l + lm - 1] = spec;
888  form[l + lm] = '\0';
889}
890
891
892static int str_format (lua_State *L) {
893  int top = lua_gettop(L);
894  int arg = 1;
895  size_t sfl;
896  const char *strfrmt = luaL_checklstring(L, arg, &sfl);
897  const char *strfrmt_end = strfrmt+sfl;
898  luaL_Buffer b;
899  luaL_buffinit(L, &b);
900  while (strfrmt < strfrmt_end) {
901    if (*strfrmt != L_ESC)
902      luaL_addchar(&b, *strfrmt++);
903    else if (*++strfrmt == L_ESC)
904      luaL_addchar(&b, *strfrmt++);  /* %% */
905    else { /* format item */
906      char form[MAX_FORMAT];  /* to store the format (`%...') */
907      char *buff = luaL_prepbuffsize(&b, MAX_ITEM);  /* to put formatted item */
908      int nb = 0;  /* number of bytes in added item */
909      if (++arg > top)
910        luaL_argerror(L, arg, "no value");
911      strfrmt = scanformat(L, strfrmt, form);
912      switch (*strfrmt++) {
913        case 'c': {
914          nb = sprintf(buff, form, luaL_checkint(L, arg));
915          break;
916        }
917        case 'd': case 'i': {
918          lua_Number n = luaL_checknumber(L, arg);
919          LUA_INTFRM_T ni = (LUA_INTFRM_T)n;
920          lua_Number diff = n - (lua_Number)ni;
921          luaL_argcheck(L, -1 < diff && diff < 1, arg,
922                        "not a number in proper range");
923          addlenmod(form, LUA_INTFRMLEN);
924          nb = sprintf(buff, form, ni);
925          break;
926        }
927        case 'o': case 'u': case 'x': case 'X': {
928          lua_Number n = luaL_checknumber(L, arg);
929          unsigned LUA_INTFRM_T ni = (unsigned LUA_INTFRM_T)n;
930          lua_Number diff = n - (lua_Number)ni;
931          luaL_argcheck(L, -1 < diff && diff < 1, arg,
932                        "not a non-negative number in proper range");
933          addlenmod(form, LUA_INTFRMLEN);
934          nb = sprintf(buff, form, ni);
935          break;
936        }
937        case 'e': case 'E': case 'f':
938#if defined(LUA_USE_AFORMAT)
939        case 'a': case 'A':
940#endif
941        case 'g': case 'G': {
942          addlenmod(form, LUA_FLTFRMLEN);
943          nb = sprintf(buff, form, (LUA_FLTFRM_T)luaL_checknumber(L, arg));
944          break;
945        }
946        case 'q': {
947          addquoted(L, &b, arg);
948          break;
949        }
950        case 's': {
951          size_t l;
952          const char *s = luaL_tolstring(L, arg, &l);
953          if (!strchr(form, '.') && l >= 100) {
954            /* no precision and string is too long to be formatted;
955               keep original string */
956            luaL_addvalue(&b);
957            break;
958          }
959          else {
960            nb = sprintf(buff, form, s);
961            lua_pop(L, 1);  /* remove result from 'luaL_tolstring' */
962            break;
963          }
964        }
965        default: {  /* also treat cases `pnLlh' */
966          return luaL_error(L, "invalid option " LUA_QL("%%%c") " to "
967                               LUA_QL("format"), *(strfrmt - 1));
968        }
969      }
970      luaL_addsize(&b, nb);
971    }
972  }
973  luaL_pushresult(&b);
974  return 1;
975}
976
977/* }====================================================== */
978
979
980static const luaL_Reg strlib[] = {
981  {"byte", str_byte},
982  {"char", str_char},
983  {"dump", str_dump},
984  {"find", str_find},
985  {"format", str_format},
986  {"gmatch", gmatch},
987  {"gsub", str_gsub},
988  {"len", str_len},
989  {"lower", str_lower},
990  {"match", str_match},
991  {"rep", str_rep},
992  {"reverse", str_reverse},
993  {"sub", str_sub},
994  {"upper", str_upper},
995  {NULL, NULL}
996};
997
998
999static void createmetatable (lua_State *L) {
1000  lua_createtable(L, 0, 1);  /* table to be metatable for strings */
1001  lua_pushliteral(L, "");  /* dummy string */
1002  lua_pushvalue(L, -2);  /* copy table */
1003  lua_setmetatable(L, -2);  /* set table as metatable for strings */
1004  lua_pop(L, 1);  /* pop dummy string */
1005  lua_pushvalue(L, -2);  /* get string library */
1006  lua_setfield(L, -2, "__index");  /* metatable.__index = string */
1007  lua_pop(L, 1);  /* pop metatable */
1008}
1009
1010
1011/*
1012** Open string library
1013*/
1014LUAMOD_API int luaopen_string (lua_State *L) {
1015  luaL_newlib(L, strlib);
1016  createmetatable(L);
1017  return 1;
1018}
1019
1020