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#define lstrlib_c
9#define LUA_LIB
10
11#include <sys/lua/lua.h>
12
13#include <sys/lua/lauxlib.h>
14#include <sys/lua/lualib.h>
15
16
17/*
18** maximum number of captures that a pattern can do during
19** pattern-matching. This limit is arbitrary.
20*/
21#if !defined(LUA_MAXCAPTURES)
22#define LUA_MAXCAPTURES		16
23#endif
24
25
26/* macro to `unsign' a character */
27#define uchar(c)	((unsigned char)(c))
28
29/*
30 * The provided version of sprintf returns a char *, but str_format expects
31 * it to return the number of characters printed. This version has the expected
32 * behavior.
33 */
34static size_t str_sprintf(char *buf, const char *fmt, ...) {
35  va_list args;
36  size_t len;
37
38  va_start(args, fmt);
39  len = vsnprintf(buf, INT_MAX, fmt, args);
40  va_end(args);
41
42  return len;
43}
44
45
46static int str_len (lua_State *L) {
47  size_t l;
48  luaL_checklstring(L, 1, &l);
49  lua_pushinteger(L, (lua_Integer)l);
50  return 1;
51}
52
53
54/* translate a relative string position: negative means back from end */
55static size_t posrelat (ptrdiff_t pos, size_t len) {
56  if (pos >= 0) return (size_t)pos;
57  else if (0u - (size_t)pos > len) return 0;
58  else return len - ((size_t)-pos) + 1;
59}
60
61
62static int str_sub (lua_State *L) {
63  size_t l;
64  const char *s = luaL_checklstring(L, 1, &l);
65  size_t start = posrelat(luaL_checkinteger(L, 2), l);
66  size_t end = posrelat(luaL_optinteger(L, 3, -1), l);
67  if (start < 1) start = 1;
68  if (end > l) end = l;
69  if (start <= end)
70    lua_pushlstring(L, s + start - 1, end - start + 1);
71  else lua_pushliteral(L, "");
72  return 1;
73}
74
75
76static int str_reverse (lua_State *L) {
77  size_t l, i;
78  luaL_Buffer b;
79  const char *s = luaL_checklstring(L, 1, &l);
80  char *p = luaL_buffinitsize(L, &b, l);
81  for (i = 0; i < l; i++)
82    p[i] = s[l - i - 1];
83  luaL_pushresultsize(&b, l);
84  return 1;
85}
86
87
88static int str_lower (lua_State *L) {
89  size_t l;
90  size_t i;
91  luaL_Buffer b;
92  const char *s = luaL_checklstring(L, 1, &l);
93  char *p = luaL_buffinitsize(L, &b, l);
94  for (i=0; i<l; i++)
95    p[i] = tolower(uchar(s[i]));
96  luaL_pushresultsize(&b, l);
97  return 1;
98}
99
100
101static int str_upper (lua_State *L) {
102  size_t l;
103  size_t i;
104  luaL_Buffer b;
105  const char *s = luaL_checklstring(L, 1, &l);
106  char *p = luaL_buffinitsize(L, &b, l);
107  for (i=0; i<l; i++)
108    p[i] = toupper(uchar(s[i]));
109  luaL_pushresultsize(&b, l);
110  return 1;
111}
112
113
114/* reasonable limit to avoid arithmetic overflow */
115#define MAXSIZE		((~(size_t)0) >> 1)
116
117static int str_rep (lua_State *L) {
118  size_t l, lsep;
119  const char *s = luaL_checklstring(L, 1, &l);
120  int n = luaL_checkint(L, 2);
121  const char *sep = luaL_optlstring(L, 3, "", &lsep);
122  if (n <= 0) lua_pushliteral(L, "");
123  else if (l + lsep < l || l + lsep >= MAXSIZE / n)  /* may overflow? */
124    return luaL_error(L, "resulting string too large");
125  else {
126    size_t totallen = n * l + (n - 1) * lsep;
127    luaL_Buffer b;
128    char *p = luaL_buffinitsize(L, &b, totallen);
129    while (n-- > 1) {  /* first n-1 copies (followed by separator) */
130      memcpy(p, s, l * sizeof(char)); p += l;
131      if (lsep > 0) {  /* avoid empty 'memcpy' (may be expensive) */
132        memcpy(p, sep, lsep * sizeof(char)); p += lsep;
133      }
134    }
135    memcpy(p, s, l * sizeof(char));  /* last copy (not followed by separator) */
136    luaL_pushresultsize(&b, totallen);
137  }
138  return 1;
139}
140
141
142static int str_byte (lua_State *L) {
143  size_t l;
144  const char *s = luaL_checklstring(L, 1, &l);
145  size_t posi = posrelat(luaL_optinteger(L, 2, 1), l);
146  size_t pose = posrelat(luaL_optinteger(L, 3, posi), l);
147  int n, i;
148  if (posi < 1) posi = 1;
149  if (pose > l) pose = l;
150  if (posi > pose) return 0;  /* empty interval; return no values */
151  n = (int)(pose -  posi + 1);
152  if (posi + n <= pose)  /* (size_t -> int) overflow? */
153    return luaL_error(L, "string slice too long");
154  luaL_checkstack(L, n, "string slice too long");
155  for (i=0; i<n; i++)
156    lua_pushinteger(L, uchar(s[posi+i-1]));
157  return n;
158}
159
160
161static int str_char (lua_State *L) {
162  int n = lua_gettop(L);  /* number of arguments */
163  int i;
164  luaL_Buffer b;
165  char *p = luaL_buffinitsize(L, &b, n);
166  for (i=1; i<=n; i++) {
167    int c = luaL_checkint(L, i);
168    luaL_argcheck(L, uchar(c) == c, i, "value out of range");
169    p[i - 1] = uchar(c);
170  }
171  luaL_pushresultsize(&b, n);
172  return 1;
173}
174
175
176#if defined(LUA_USE_DUMP)
177static int writer (lua_State *L, const void* b, size_t size, void* B) {
178  (void)L;
179  luaL_addlstring((luaL_Buffer*) B, (const char *)b, size);
180  return 0;
181}
182
183
184static int str_dump (lua_State *L) {
185  luaL_Buffer b;
186  luaL_checktype(L, 1, LUA_TFUNCTION);
187  lua_settop(L, 1);
188  luaL_buffinit(L,&b);
189  if (lua_dump(L, writer, &b) != 0)
190    return luaL_error(L, "unable to dump given function");
191  luaL_pushresult(&b);
192  return 1;
193}
194#endif
195
196
197/*
198** {======================================================
199** PATTERN MATCHING
200** =======================================================
201*/
202
203
204#define CAP_UNFINISHED	(-1)
205#define CAP_POSITION	(-2)
206
207
208typedef struct MatchState {
209  int matchdepth;  /* control for recursive depth (to avoid C stack overflow) */
210  const char *src_init;  /* init of source string */
211  const char *src_end;  /* end ('\0') of source string */
212  const char *p_end;  /* end ('\0') of pattern */
213  lua_State *L;
214  int level;  /* total number of captures (finished or unfinished) */
215  struct {
216    const char *init;
217    ptrdiff_t len;
218  } capture[LUA_MAXCAPTURES];
219} MatchState;
220
221
222/* recursive function */
223static const char *match (MatchState *ms, const char *s, const char *p);
224
225
226/* maximum recursion depth for 'match' */
227#if !defined(MAXCCALLS)
228#define MAXCCALLS	200
229#endif
230
231
232#define L_ESC		'%'
233#define SPECIALS	"^$*+?.([%-"
234
235
236static int check_capture (MatchState *ms, int l) {
237  l -= '1';
238  if (l < 0 || l >= ms->level || ms->capture[l].len == CAP_UNFINISHED)
239    return luaL_error(ms->L, "invalid capture index %%%d", l + 1);
240  return l;
241}
242
243
244static int capture_to_close (MatchState *ms) {
245  int level = ms->level;
246  for (level--; level>=0; level--)
247    if (ms->capture[level].len == CAP_UNFINISHED) return level;
248  return luaL_error(ms->L, "invalid pattern capture");
249}
250
251
252static const char *classend (MatchState *ms, const char *p) {
253  switch (*p++) {
254    case L_ESC: {
255      if (p == ms->p_end)
256        luaL_error(ms->L, "malformed pattern (ends with " LUA_QL("%%") ")");
257      return p+1;
258    }
259    case '[': {
260      if (*p == '^') p++;
261      do {  /* look for a `]' */
262        if (p == ms->p_end)
263          luaL_error(ms->L, "malformed pattern (missing " LUA_QL("]") ")");
264        if (*(p++) == L_ESC && p < ms->p_end)
265          p++;  /* skip escapes (e.g. `%]') */
266      } while (*p != ']');
267      return p+1;
268    }
269    default: {
270      return p;
271    }
272  }
273}
274
275
276static int match_class (int c, int cl) {
277  int res;
278  switch (tolower(cl)) {
279    case 'a' : res = isalpha(c); break;
280    case 'c' : res = iscntrl(c); break;
281    case 'd' : res = isdigit(c); break;
282    case 'g' : res = isgraph(c); break;
283    case 'l' : res = islower(c); break;
284    case 'p' : res = ispunct(c); break;
285    case 's' : res = isspace(c); break;
286    case 'u' : res = isupper(c); break;
287    case 'w' : res = isalnum(c); break;
288    case 'x' : res = isxdigit(c); break;
289    case 'z' : res = (c == 0); break;  /* deprecated option */
290    default: return (cl == c);
291  }
292  return (islower(cl) ? res : !res);
293}
294
295
296static int matchbracketclass (int c, const char *p, const char *ec) {
297  int sig = 1;
298  if (*(p+1) == '^') {
299    sig = 0;
300    p++;  /* skip the `^' */
301  }
302  while (++p < ec) {
303    if (*p == L_ESC) {
304      p++;
305      if (match_class(c, uchar(*p)))
306        return sig;
307    }
308    else if ((*(p+1) == '-') && (p+2 < ec)) {
309      p+=2;
310      if (uchar(*(p-2)) <= c && c <= uchar(*p))
311        return sig;
312    }
313    else if (uchar(*p) == c) return sig;
314  }
315  return !sig;
316}
317
318
319static int singlematch (MatchState *ms, const char *s, const char *p,
320                        const char *ep) {
321  if (s >= ms->src_end)
322    return 0;
323  else {
324    int c = uchar(*s);
325    switch (*p) {
326      case '.': return 1;  /* matches any char */
327      case L_ESC: return match_class(c, uchar(*(p+1)));
328      case '[': return matchbracketclass(c, p, ep-1);
329      default:  return (uchar(*p) == c);
330    }
331  }
332}
333
334
335static const char *matchbalance (MatchState *ms, const char *s,
336                                   const char *p) {
337  if (p >= ms->p_end - 1)
338    luaL_error(ms->L, "malformed pattern "
339                      "(missing arguments to " LUA_QL("%%b") ")");
340  if (*s != *p) return NULL;
341  else {
342    int b = *p;
343    int e = *(p+1);
344    int cont = 1;
345    while (++s < ms->src_end) {
346      if (*s == e) {
347        if (--cont == 0) return s+1;
348      }
349      else if (*s == b) cont++;
350    }
351  }
352  return NULL;  /* string ends out of balance */
353}
354
355
356static const char *max_expand (MatchState *ms, const char *s,
357                                 const char *p, const char *ep) {
358  ptrdiff_t i = 0;  /* counts maximum expand for item */
359  while (singlematch(ms, s + i, p, ep))
360    i++;
361  /* keeps trying to match with the maximum repetitions */
362  while (i>=0) {
363    const char *res = match(ms, (s+i), ep+1);
364    if (res) return res;
365    i--;  /* else didn't match; reduce 1 repetition to try again */
366  }
367  return NULL;
368}
369
370
371static const char *min_expand (MatchState *ms, const char *s,
372                                 const char *p, const char *ep) {
373  for (;;) {
374    const char *res = match(ms, s, ep+1);
375    if (res != NULL)
376      return res;
377    else if (singlematch(ms, s, p, ep))
378      s++;  /* try with one more repetition */
379    else return NULL;
380  }
381}
382
383
384static const char *start_capture (MatchState *ms, const char *s,
385                                    const char *p, int what) {
386  const char *res;
387  int level = ms->level;
388  if (level >= LUA_MAXCAPTURES) luaL_error(ms->L, "too many captures");
389  ms->capture[level].init = s;
390  ms->capture[level].len = what;
391  ms->level = level+1;
392  if ((res=match(ms, s, p)) == NULL)  /* match failed? */
393    ms->level--;  /* undo capture */
394  return res;
395}
396
397
398static const char *end_capture (MatchState *ms, const char *s,
399                                  const char *p) {
400  int l = capture_to_close(ms);
401  const char *res;
402  ms->capture[l].len = s - ms->capture[l].init;  /* close capture */
403  if ((res = match(ms, s, p)) == NULL)  /* match failed? */
404    ms->capture[l].len = CAP_UNFINISHED;  /* undo capture */
405  return res;
406}
407
408
409static const char *match_capture (MatchState *ms, const char *s, int l) {
410  size_t len;
411  l = check_capture(ms, l);
412  len = ms->capture[l].len;
413  if ((size_t)(ms->src_end-s) >= len &&
414      memcmp(ms->capture[l].init, s, len) == 0)
415    return s+len;
416  else return NULL;
417}
418
419
420static const char *match (MatchState *ms, const char *s, const char *p) {
421  if (ms->matchdepth-- == 0)
422    luaL_error(ms->L, "pattern too complex");
423  init: /* using goto's to optimize tail recursion */
424  if (p != ms->p_end) {  /* end of pattern? */
425    switch (*p) {
426      case '(': {  /* start capture */
427        if (*(p + 1) == ')')  /* position capture? */
428          s = start_capture(ms, s, p + 2, CAP_POSITION);
429        else
430          s = start_capture(ms, s, p + 1, CAP_UNFINISHED);
431        break;
432      }
433      case ')': {  /* end capture */
434        s = end_capture(ms, s, p + 1);
435        break;
436      }
437      case '$': {
438        if ((p + 1) != ms->p_end)  /* is the `$' the last char in pattern? */
439          goto dflt;  /* no; go to default */
440        s = (s == ms->src_end) ? s : NULL;  /* check end of string */
441        break;
442      }
443      case L_ESC: {  /* escaped sequences not in the format class[*+?-]? */
444        switch (*(p + 1)) {
445          case 'b': {  /* balanced string? */
446            s = matchbalance(ms, s, p + 2);
447            if (s != NULL) {
448              p += 4; goto init;  /* return match(ms, s, p + 4); */
449            }  /* else fail (s == NULL) */
450            break;
451          }
452          case 'f': {  /* frontier? */
453            const char *ep; char previous;
454            p += 2;
455            if (*p != '[')
456              luaL_error(ms->L, "missing " LUA_QL("[") " after "
457                                 LUA_QL("%%f") " in pattern");
458            ep = classend(ms, p);  /* points to what is next */
459            previous = (s == ms->src_init) ? '\0' : *(s - 1);
460            if (!matchbracketclass(uchar(previous), p, ep - 1) &&
461               matchbracketclass(uchar(*s), p, ep - 1)) {
462              p = ep; goto init;  /* return match(ms, s, ep); */
463            }
464            s = NULL;  /* match failed */
465            break;
466          }
467          case '0': case '1': case '2': case '3':
468          case '4': case '5': case '6': case '7':
469          case '8': case '9': {  /* capture results (%0-%9)? */
470            s = match_capture(ms, s, uchar(*(p + 1)));
471            if (s != NULL) {
472              p += 2; goto init;  /* return match(ms, s, p + 2) */
473            }
474            break;
475          }
476          default: goto dflt;
477        }
478        break;
479      }
480      default: dflt: {  /* pattern class plus optional suffix */
481        const char *ep = classend(ms, p);  /* points to optional suffix */
482        /* does not match at least once? */
483        if (!singlematch(ms, s, p, ep)) {
484          if (*ep == '*' || *ep == '?' || *ep == '-') {  /* accept empty? */
485            p = ep + 1; goto init;  /* return match(ms, s, ep + 1); */
486          }
487          else  /* '+' or no suffix */
488            s = NULL;  /* fail */
489        }
490        else {  /* matched once */
491          switch (*ep) {  /* handle optional suffix */
492            case '?': {  /* optional */
493              const char *res;
494              if ((res = match(ms, s + 1, ep + 1)) != NULL)
495                s = res;
496              else {
497                p = ep + 1; goto init;  /* else return match(ms, s, ep + 1); */
498              }
499              break;
500            }
501            case '+':  /* 1 or more repetitions */
502              s++;  /* 1 match already done */
503              zfs_fallthrough;
504            case '*':  /* 0 or more repetitions */
505              s = max_expand(ms, s, p, ep);
506              break;
507            case '-':  /* 0 or more repetitions (minimum) */
508              s = min_expand(ms, s, p, ep);
509              break;
510            default:  /* no suffix */
511              s++; p = ep; goto init;  /* return match(ms, s + 1, ep); */
512          }
513        }
514        break;
515      }
516    }
517  }
518  ms->matchdepth++;
519  return s;
520}
521
522
523
524static const char *lmemfind (const char *s1, size_t l1,
525                               const char *s2, size_t l2) {
526  if (l2 == 0) return s1;  /* empty strings are everywhere */
527  else if (l2 > l1) return NULL;  /* avoids a negative `l1' */
528  else {
529    const char *init;  /* to search for a `*s2' inside `s1' */
530    l2--;  /* 1st char will be checked by `memchr' */
531    l1 = l1-l2;  /* `s2' cannot be found after that */
532    while (l1 > 0 && (init = (const char *)memchr(s1, *s2, l1)) != NULL) {
533      init++;   /* 1st char is already checked */
534      if (memcmp(init, s2+1, l2) == 0)
535        return init-1;
536      else {  /* correct `l1' and `s1' to try again */
537        l1 -= init-s1;
538        s1 = init;
539      }
540    }
541    return NULL;  /* not found */
542  }
543}
544
545
546static void push_onecapture (MatchState *ms, int i, const char *s,
547                                                    const char *e) {
548  if (i >= ms->level) {
549    if (i == 0)  /* ms->level == 0, too */
550      lua_pushlstring(ms->L, s, e - s);  /* add whole match */
551    else
552      luaL_error(ms->L, "invalid capture index");
553  }
554  else {
555    ptrdiff_t l = ms->capture[i].len;
556    if (l == CAP_UNFINISHED) luaL_error(ms->L, "unfinished capture");
557    if (l == CAP_POSITION)
558      lua_pushinteger(ms->L, ms->capture[i].init - ms->src_init + 1);
559    else
560      lua_pushlstring(ms->L, ms->capture[i].init, l);
561  }
562}
563
564
565static int push_captures (MatchState *ms, const char *s, const char *e) {
566  int i;
567  int nlevels = (ms->level == 0 && s) ? 1 : ms->level;
568  luaL_checkstack(ms->L, nlevels, "too many captures");
569  for (i = 0; i < nlevels; i++)
570    push_onecapture(ms, i, s, e);
571  return nlevels;  /* number of strings pushed */
572}
573
574
575/* check whether pattern has no special characters */
576static int nospecials (const char *p, size_t l) {
577  size_t upto = 0;
578  do {
579    if (strpbrk(p + upto, SPECIALS))
580      return 0;  /* pattern has a special character */
581    upto += strlen(p + upto) + 1;  /* may have more after \0 */
582  } while (upto <= l);
583  return 1;  /* no special chars found */
584}
585
586
587static int str_find_aux (lua_State *L, int find) {
588  size_t ls, lp;
589  const char *s = luaL_checklstring(L, 1, &ls);
590  const char *p = luaL_checklstring(L, 2, &lp);
591  size_t init = posrelat(luaL_optinteger(L, 3, 1), ls);
592  if (init < 1) init = 1;
593  else if (init > ls + 1) {  /* start after string's end? */
594    lua_pushnil(L);  /* cannot find anything */
595    return 1;
596  }
597  /* explicit request or no special characters? */
598  if (find && (lua_toboolean(L, 4) || nospecials(p, lp))) {
599    /* do a plain search */
600    const char *s2 = lmemfind(s + init - 1, ls - init + 1, p, lp);
601    if (s2) {
602      lua_pushinteger(L, s2 - s + 1);
603      lua_pushinteger(L, s2 - s + lp);
604      return 2;
605    }
606  }
607  else {
608    MatchState ms;
609    const char *s1 = s + init - 1;
610    int anchor = (*p == '^');
611    if (anchor) {
612      p++; lp--;  /* skip anchor character */
613    }
614    ms.L = L;
615    ms.matchdepth = MAXCCALLS;
616    ms.src_init = s;
617    ms.src_end = s + ls;
618    ms.p_end = p + lp;
619    do {
620      const char *res;
621      ms.level = 0;
622      lua_assert(ms.matchdepth == MAXCCALLS);
623      if ((res=match(&ms, s1, p)) != NULL) {
624        if (find) {
625          lua_pushinteger(L, s1 - s + 1);  /* start */
626          lua_pushinteger(L, res - s);   /* end */
627          return push_captures(&ms, NULL, 0) + 2;
628        }
629        else
630          return push_captures(&ms, s1, res);
631      }
632    } while (s1++ < ms.src_end && !anchor);
633  }
634  lua_pushnil(L);  /* not found */
635  return 1;
636}
637
638
639static int str_find (lua_State *L) {
640  return str_find_aux(L, 1);
641}
642
643
644static int str_match (lua_State *L) {
645  return str_find_aux(L, 0);
646}
647
648
649static int gmatch_aux (lua_State *L) {
650  MatchState ms;
651  size_t ls, lp;
652  const char *s = lua_tolstring(L, lua_upvalueindex(1), &ls);
653  const char *p = lua_tolstring(L, lua_upvalueindex(2), &lp);
654  const char *src;
655  ms.L = L;
656  ms.matchdepth = MAXCCALLS;
657  ms.src_init = s;
658  ms.src_end = s+ls;
659  ms.p_end = p + lp;
660  for (src = s + (size_t)lua_tointeger(L, lua_upvalueindex(3));
661       src <= ms.src_end;
662       src++) {
663    const char *e;
664    ms.level = 0;
665    lua_assert(ms.matchdepth == MAXCCALLS);
666    if ((e = match(&ms, src, p)) != NULL) {
667      lua_Integer newstart = e-s;
668      if (e == src) newstart++;  /* empty match? go at least one position */
669      lua_pushinteger(L, newstart);
670      lua_replace(L, lua_upvalueindex(3));
671      return push_captures(&ms, src, e);
672    }
673  }
674  return 0;  /* not found */
675}
676
677
678static int str_gmatch (lua_State *L) {
679  luaL_checkstring(L, 1);
680  luaL_checkstring(L, 2);
681  lua_settop(L, 2);
682  lua_pushinteger(L, 0);
683  lua_pushcclosure(L, gmatch_aux, 3);
684  return 1;
685}
686
687
688static void add_s (MatchState *ms, luaL_Buffer *b, const char *s,
689                                                   const char *e) {
690  size_t l, i;
691  const char *news = lua_tolstring(ms->L, 3, &l);
692  for (i = 0; i < l; i++) {
693    if (news[i] != L_ESC)
694      luaL_addchar(b, news[i]);
695    else {
696      i++;  /* skip ESC */
697      if (!isdigit(uchar(news[i]))) {
698        if (news[i] != L_ESC)
699          luaL_error(ms->L, "invalid use of " LUA_QL("%c")
700                           " in replacement string", L_ESC);
701        luaL_addchar(b, news[i]);
702      }
703      else if (news[i] == '0')
704          luaL_addlstring(b, s, e - s);
705      else {
706        push_onecapture(ms, news[i] - '1', s, e);
707        luaL_addvalue(b);  /* add capture to accumulated result */
708      }
709    }
710  }
711}
712
713
714static void add_value (MatchState *ms, luaL_Buffer *b, const char *s,
715                                       const char *e, int tr) {
716  lua_State *L = ms->L;
717  switch (tr) {
718    case LUA_TFUNCTION: {
719      int n;
720      lua_pushvalue(L, 3);
721      n = push_captures(ms, s, e);
722      lua_call(L, n, 1);
723      break;
724    }
725    case LUA_TTABLE: {
726      push_onecapture(ms, 0, s, e);
727      lua_gettable(L, 3);
728      break;
729    }
730    default: {  /* LUA_TNUMBER or LUA_TSTRING */
731      add_s(ms, b, s, e);
732      return;
733    }
734  }
735  if (!lua_toboolean(L, -1)) {  /* nil or false? */
736    lua_pop(L, 1);
737    lua_pushlstring(L, s, e - s);  /* keep original text */
738  }
739  else if (!lua_isstring(L, -1))
740    luaL_error(L, "invalid replacement value (a %s)", luaL_typename(L, -1));
741  luaL_addvalue(b);  /* add result to accumulator */
742}
743
744
745static int str_gsub (lua_State *L) {
746  size_t srcl, lp;
747  const char *src = luaL_checklstring(L, 1, &srcl);
748  const char *p = luaL_checklstring(L, 2, &lp);
749  int tr = lua_type(L, 3);
750  size_t max_s = luaL_optinteger(L, 4, srcl+1);
751  int anchor = (*p == '^');
752  size_t n = 0;
753  MatchState ms;
754  luaL_Buffer b;
755  luaL_argcheck(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||
756                   tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3,
757                      "string/function/table expected");
758  luaL_buffinit(L, &b);
759  if (anchor) {
760    p++; lp--;  /* skip anchor character */
761  }
762  ms.L = L;
763  ms.matchdepth = MAXCCALLS;
764  ms.src_init = src;
765  ms.src_end = src+srcl;
766  ms.p_end = p + lp;
767  while (n < max_s) {
768    const char *e;
769    ms.level = 0;
770    lua_assert(ms.matchdepth == MAXCCALLS);
771    e = match(&ms, src, p);
772    if (e) {
773      n++;
774      add_value(&ms, &b, src, e, tr);
775    }
776    if (e && e>src) /* non empty match? */
777      src = e;  /* skip it */
778    else if (src < ms.src_end)
779      luaL_addchar(&b, *src++);
780    else break;
781    if (anchor) break;
782  }
783  luaL_addlstring(&b, src, ms.src_end-src);
784  luaL_pushresult(&b);
785  lua_pushinteger(L, n);  /* number of substitutions */
786  return 2;
787}
788
789/* }====================================================== */
790
791
792
793/*
794** {======================================================
795** STRING FORMAT
796** =======================================================
797*/
798
799/*
800** LUA_INTFRMLEN is the length modifier for integer conversions in
801** 'string.format'; LUA_INTFRM_T is the integer type corresponding to
802** the previous length
803*/
804#if !defined(LUA_INTFRMLEN)	/* { */
805#if defined(LUA_USE_LONGLONG)
806
807#define LUA_INTFRMLEN		"ll"
808#define LUA_INTFRM_T		long long
809
810#else
811
812#define LUA_INTFRMLEN		"l"
813#define LUA_INTFRM_T		long
814
815#endif
816#endif				/* } */
817
818
819/*
820** LUA_FLTFRMLEN is the length modifier for float conversions in
821** 'string.format'; LUA_FLTFRM_T is the float type corresponding to
822** the previous length
823*/
824#if !defined(LUA_FLTFRMLEN)
825
826#define LUA_FLTFRMLEN		""
827#define LUA_FLTFRM_T		double
828
829#endif
830
831
832/* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */
833#define MAX_ITEM	512
834/* valid flags in a format specification */
835#define FLAGS	"-+ #0"
836/*
837** maximum size of each format specification (such as '%-099.99d')
838** (+10 accounts for %99.99x plus margin of error)
839*/
840#define MAX_FORMAT	(sizeof(FLAGS) + sizeof(LUA_INTFRMLEN) + 10)
841
842
843static void addquoted (lua_State *L, luaL_Buffer *b, int arg) {
844  size_t l;
845  const char *s = luaL_checklstring(L, arg, &l);
846  luaL_addchar(b, '"');
847  while (l--) {
848    if (*s == '"' || *s == '\\' || *s == '\n') {
849      luaL_addchar(b, '\\');
850      luaL_addchar(b, *s);
851    }
852    else if (*s == '\0' || iscntrl(uchar(*s))) {
853      char buff[10];
854      if (!isdigit(uchar(*(s+1))))
855        snprintf(buff, sizeof(buff), "\\%d", (int)uchar(*s));
856      else
857        snprintf(buff, sizeof(buff), "\\%03d", (int)uchar(*s));
858      luaL_addstring(b, buff);
859    }
860    else
861      luaL_addchar(b, *s);
862    s++;
863  }
864  luaL_addchar(b, '"');
865}
866
867static const char *scanformat (lua_State *L, const char *strfrmt, char *form) {
868  const char *p = strfrmt;
869  while (*p != '\0' && strchr(FLAGS, *p) != NULL) p++;  /* skip flags */
870  if ((size_t)(p - strfrmt) >= sizeof(FLAGS)/sizeof(char))
871    luaL_error(L, "invalid format (repeated flags)");
872  if (isdigit(uchar(*p))) p++;  /* skip width */
873  if (isdigit(uchar(*p))) p++;  /* (2 digits at most) */
874  if (*p == '.') {
875    p++;
876    if (isdigit(uchar(*p))) p++;  /* skip precision */
877    if (isdigit(uchar(*p))) p++;  /* (2 digits at most) */
878  }
879  if (isdigit(uchar(*p)))
880    luaL_error(L, "invalid format (width or precision too long)");
881  *(form++) = '%';
882  memcpy(form, strfrmt, (p - strfrmt + 1) * sizeof(char));
883  form += p - strfrmt + 1;
884  *form = '\0';
885  return p;
886}
887
888
889/*
890** add length modifier into formats
891*/
892static void addlenmod (char *form, const char *lenmod, size_t size) {
893  size_t l = strlen(form);
894  size_t lm = strlen(lenmod);
895  char spec = form[l - 1];
896  strlcpy(form + l - 1, lenmod, size - (l - 1));
897  form[l + lm - 1] = spec;
898  form[l + lm] = '\0';
899}
900
901
902static int str_format (lua_State *L) {
903  int top = lua_gettop(L);
904  int arg = 1;
905  size_t sfl;
906  const char *strfrmt = luaL_checklstring(L, arg, &sfl);
907  const char *strfrmt_end = strfrmt+sfl;
908  luaL_Buffer b;
909  luaL_buffinit(L, &b);
910  while (strfrmt < strfrmt_end) {
911    if (*strfrmt != L_ESC)
912      luaL_addchar(&b, *strfrmt++);
913    else if (*++strfrmt == L_ESC)
914      luaL_addchar(&b, *strfrmt++);  /* %% */
915    else { /* format item */
916      char form[MAX_FORMAT];  /* to store the format (`%...') */
917      char *buff = luaL_prepbuffsize(&b, MAX_ITEM);  /* to put formatted item */
918      int nb = 0;  /* number of bytes in added item */
919      if (++arg > top)
920        luaL_argerror(L, arg, "no value");
921      strfrmt = scanformat(L, strfrmt, form);
922      switch (*strfrmt++) {
923        case 'c': {
924          nb = str_sprintf(buff, form, luaL_checkint(L, arg));
925          break;
926        }
927        case 'd': case 'i': {
928          lua_Number n = luaL_checknumber(L, arg);
929          LUA_INTFRM_T ni = (LUA_INTFRM_T)n;
930          lua_Number diff = n - (lua_Number)ni;
931          luaL_argcheck(L, -1 < diff && diff < 1, arg,
932                        "not a number in proper range");
933          addlenmod(form, LUA_INTFRMLEN, MAX_FORMAT);
934          nb = str_sprintf(buff, form, ni);
935          break;
936        }
937        case 'o': case 'u': case 'x': case 'X': {
938          lua_Number n = luaL_checknumber(L, arg);
939          unsigned LUA_INTFRM_T ni = (unsigned LUA_INTFRM_T)n;
940          lua_Number diff = n - (lua_Number)ni;
941          luaL_argcheck(L, -1 < diff && diff < 1, arg,
942                        "not a non-negative number in proper range");
943          addlenmod(form, LUA_INTFRMLEN, MAX_FORMAT);
944          nb = str_sprintf(buff, form, ni);
945          break;
946        }
947#if defined(LUA_USE_FLOAT_FORMATS)
948        case 'e': case 'E': case 'f':
949#if defined(LUA_USE_AFORMAT)
950        case 'a': case 'A':
951#endif
952        case 'g': case 'G': {
953          addlenmod(form, LUA_FLTFRMLEN, MAX_FORMAT);
954          nb = str_sprintf(buff, form, (LUA_FLTFRM_T)luaL_checknumber(L, arg));
955          break;
956        }
957#endif
958        case 'q': {
959          addquoted(L, &b, arg);
960          break;
961        }
962        case 's': {
963          size_t l;
964          const char *s = luaL_tolstring(L, arg, &l);
965          if (!strchr(form, '.') && l >= 100) {
966            /* no precision and string is too long to be formatted;
967               keep original string */
968            luaL_addvalue(&b);
969            break;
970          }
971          else {
972            nb = str_sprintf(buff, form, s);
973            lua_pop(L, 1);  /* remove result from 'luaL_tolstring' */
974            break;
975          }
976        }
977        default: {  /* also treat cases `pnLlh' */
978          return luaL_error(L, "invalid option " LUA_QL("%%%c") " to "
979                               LUA_QL("format"), *(strfrmt - 1));
980        }
981      }
982      luaL_addsize(&b, nb);
983    }
984  }
985  luaL_pushresult(&b);
986  return 1;
987}
988
989/* }====================================================== */
990
991
992static const luaL_Reg strlib[] = {
993  {"byte", str_byte},
994  {"char", str_char},
995#if defined(LUA_USE_DUMP)
996  {"dump", str_dump},
997#endif
998  {"find", str_find},
999  {"format", str_format},
1000  {"gmatch", str_gmatch},
1001  {"gsub", str_gsub},
1002  {"len", str_len},
1003  {"lower", str_lower},
1004  {"match", str_match},
1005  {"rep", str_rep},
1006  {"reverse", str_reverse},
1007  {"sub", str_sub},
1008  {"upper", str_upper},
1009  {NULL, NULL}
1010};
1011
1012
1013static void createmetatable (lua_State *L) {
1014  lua_createtable(L, 0, 1);  /* table to be metatable for strings */
1015  lua_pushliteral(L, "");  /* dummy string */
1016  lua_pushvalue(L, -2);  /* copy table */
1017  lua_setmetatable(L, -2);  /* set table as metatable for strings */
1018  lua_pop(L, 1);  /* pop dummy string */
1019  lua_pushvalue(L, -2);  /* get string library */
1020  lua_setfield(L, -2, "__index");  /* metatable.__index = string */
1021  lua_pop(L, 1);  /* pop metatable */
1022}
1023
1024
1025/*
1026** Open string library
1027*/
1028LUAMOD_API int luaopen_string (lua_State *L) {
1029  luaL_newlib(L, strlib);
1030  createmetatable(L);
1031  return 1;
1032}
1033
1034#if defined(_KERNEL)
1035
1036EXPORT_SYMBOL(luaopen_string);
1037
1038#endif
1039