1/*	$NetBSD$	*/
2
3/*
4** Id: lstrlib.c,v 1.132.1.4 2008/07/11 17:27:21 roberto Exp
5** Standard library for string operations and pattern-matching
6** See Copyright Notice in lua.h
7*/
8
9
10#include <ctype.h>
11#include <stddef.h>
12#include <stdio.h>
13#include <stdlib.h>
14#include <string.h>
15
16#define lstrlib_c
17#define LUA_LIB
18
19#include "lua.h"
20
21#include "lauxlib.h"
22#include "lualib.h"
23
24
25/* macro to `unsign' a character */
26#define uchar(c)        ((unsigned char)(c))
27
28
29
30static int str_len (lua_State *L) {
31  size_t l;
32  luaL_checklstring(L, 1, &l);
33  lua_pushinteger(L, l);
34  return 1;
35}
36
37
38static ptrdiff_t posrelat (ptrdiff_t pos, size_t len) {
39  /* relative string position: negative means back from end */
40  if (pos < 0) pos += (ptrdiff_t)len + 1;
41  return (pos >= 0) ? pos : 0;
42}
43
44
45static int str_sub (lua_State *L) {
46  size_t l;
47  const char *s = luaL_checklstring(L, 1, &l);
48  ptrdiff_t start = posrelat(luaL_checkinteger(L, 2), l);
49  ptrdiff_t end = posrelat(luaL_optinteger(L, 3, -1), l);
50  if (start < 1) start = 1;
51  if (end > (ptrdiff_t)l) end = (ptrdiff_t)l;
52  if (start <= end)
53    lua_pushlstring(L, s+start-1, end-start+1);
54  else lua_pushliteral(L, "");
55  return 1;
56}
57
58
59static int str_reverse (lua_State *L) {
60  size_t l;
61  luaL_Buffer b;
62  const char *s = luaL_checklstring(L, 1, &l);
63  luaL_buffinit(L, &b);
64  while (l--) luaL_addchar(&b, s[l]);
65  luaL_pushresult(&b);
66  return 1;
67}
68
69
70static int str_lower (lua_State *L) {
71  size_t l;
72  size_t i;
73  luaL_Buffer b;
74  const char *s = luaL_checklstring(L, 1, &l);
75  luaL_buffinit(L, &b);
76  for (i=0; i<l; i++)
77    luaL_addchar(&b, tolower(uchar(s[i])));
78  luaL_pushresult(&b);
79  return 1;
80}
81
82
83static int str_upper (lua_State *L) {
84  size_t l;
85  size_t i;
86  luaL_Buffer b;
87  const char *s = luaL_checklstring(L, 1, &l);
88  luaL_buffinit(L, &b);
89  for (i=0; i<l; i++)
90    luaL_addchar(&b, toupper(uchar(s[i])));
91  luaL_pushresult(&b);
92  return 1;
93}
94
95static int str_rep (lua_State *L) {
96  size_t l;
97  luaL_Buffer b;
98  const char *s = luaL_checklstring(L, 1, &l);
99  int n = luaL_checkint(L, 2);
100  luaL_buffinit(L, &b);
101  while (n-- > 0)
102    luaL_addlstring(&b, s, l);
103  luaL_pushresult(&b);
104  return 1;
105}
106
107
108static int str_byte (lua_State *L) {
109  size_t l;
110  const char *s = luaL_checklstring(L, 1, &l);
111  ptrdiff_t posi = posrelat(luaL_optinteger(L, 2, 1), l);
112  ptrdiff_t pose = posrelat(luaL_optinteger(L, 3, posi), l);
113  int n, i;
114  if (posi <= 0) posi = 1;
115  if ((size_t)pose > l) pose = l;
116  if (posi > pose) return 0;  /* empty interval; return no values */
117  n = (int)(pose -  posi + 1);
118  if (posi + n <= pose)  /* overflow? */
119    luaL_error(L, "string slice too long");
120  luaL_checkstack(L, n, "string slice too long");
121  for (i=0; i<n; i++)
122    lua_pushinteger(L, uchar(s[posi+i-1]));
123  return n;
124}
125
126
127static int str_char (lua_State *L) {
128  int n = lua_gettop(L);  /* number of arguments */
129  int i;
130  luaL_Buffer b;
131  luaL_buffinit(L, &b);
132  for (i=1; i<=n; i++) {
133    int c = luaL_checkint(L, i);
134    luaL_argcheck(L, uchar(c) == c, i, "invalid value");
135    luaL_addchar(&b, uchar(c));
136  }
137  luaL_pushresult(&b);
138  return 1;
139}
140
141
142static int writer (lua_State *L, const void* b, size_t size, void* B) {
143  (void)L;
144  luaL_addlstring((luaL_Buffer*) B, (const char *)b, size);
145  return 0;
146}
147
148
149static int str_dump (lua_State *L) {
150  luaL_Buffer b;
151  luaL_checktype(L, 1, LUA_TFUNCTION);
152  lua_settop(L, 1);
153  luaL_buffinit(L,&b);
154  if (lua_dump(L, writer, &b) != 0)
155    luaL_error(L, "unable to dump given function");
156  luaL_pushresult(&b);
157  return 1;
158}
159
160
161
162/*
163** {======================================================
164** PATTERN MATCHING
165** =======================================================
166*/
167
168
169#define CAP_UNFINISHED	(-1)
170#define CAP_POSITION	(-2)
171
172typedef struct MatchState {
173  const char *src_init;  /* init of source string */
174  const char *src_end;  /* end (`\0') of source string */
175  lua_State *L;
176  int level;  /* total number of captures (finished or unfinished) */
177  struct {
178    const char *init;
179    ptrdiff_t len;
180  } capture[LUA_MAXCAPTURES];
181} MatchState;
182
183
184#define L_ESC		'%'
185#define SPECIALS	"^$*+?.([%-"
186
187
188static int check_capture (MatchState *ms, int l) {
189  l -= '1';
190  if (l < 0 || l >= ms->level || ms->capture[l].len == CAP_UNFINISHED)
191    return luaL_error(ms->L, "invalid capture index");
192  return l;
193}
194
195
196static int capture_to_close (MatchState *ms) {
197  int level = ms->level;
198  for (level--; level>=0; level--)
199    if (ms->capture[level].len == CAP_UNFINISHED) return level;
200  return luaL_error(ms->L, "invalid pattern capture");
201}
202
203
204static const char *classend (MatchState *ms, const char *p) {
205  switch (*p++) {
206    case L_ESC: {
207      if (*p == '\0')
208        luaL_error(ms->L, "malformed pattern (ends with " LUA_QL("%%") ")");
209      return p+1;
210    }
211    case '[': {
212      if (*p == '^') p++;
213      do {  /* look for a `]' */
214        if (*p == '\0')
215          luaL_error(ms->L, "malformed pattern (missing " LUA_QL("]") ")");
216        if (*(p++) == L_ESC && *p != '\0')
217          p++;  /* skip escapes (e.g. `%]') */
218      } while (*p != ']');
219      return p+1;
220    }
221    default: {
222      return p;
223    }
224  }
225}
226
227
228static int match_class (int c, int cl) {
229  int res;
230  switch (tolower(cl)) {
231    case 'a' : res = isalpha(c); break;
232    case 'c' : res = iscntrl(c); break;
233    case 'd' : res = isdigit(c); break;
234    case 'l' : res = islower(c); break;
235    case 'p' : res = ispunct(c); break;
236    case 's' : res = isspace(c); break;
237    case 'u' : res = isupper(c); break;
238    case 'w' : res = isalnum(c); break;
239    case 'x' : res = isxdigit(c); break;
240    case 'z' : res = (c == 0); break;
241    default: return (cl == c);
242  }
243  return (islower(cl) ? res : !res);
244}
245
246
247static int matchbracketclass (int c, const char *p, const char *ec) {
248  int sig = 1;
249  if (*(p+1) == '^') {
250    sig = 0;
251    p++;  /* skip the `^' */
252  }
253  while (++p < ec) {
254    if (*p == L_ESC) {
255      p++;
256      if (match_class(c, uchar(*p)))
257        return sig;
258    }
259    else if ((*(p+1) == '-') && (p+2 < ec)) {
260      p+=2;
261      if (uchar(*(p-2)) <= c && c <= uchar(*p))
262        return sig;
263    }
264    else if (uchar(*p) == c) return sig;
265  }
266  return !sig;
267}
268
269
270static int singlematch (int c, const char *p, const char *ep) {
271  switch (*p) {
272    case '.': return 1;  /* matches any char */
273    case L_ESC: return match_class(c, uchar(*(p+1)));
274    case '[': return matchbracketclass(c, p, ep-1);
275    default:  return (uchar(*p) == c);
276  }
277}
278
279
280static const char *match (MatchState *ms, const char *s, const char *p);
281
282
283static const char *matchbalance (MatchState *ms, const char *s,
284                                   const char *p) {
285  if (*p == 0 || *(p+1) == 0)
286    luaL_error(ms->L, "unbalanced pattern");
287  if (*s != *p) return NULL;
288  else {
289    int b = *p;
290    int e = *(p+1);
291    int cont = 1;
292    while (++s < ms->src_end) {
293      if (*s == e) {
294        if (--cont == 0) return s+1;
295      }
296      else if (*s == b) cont++;
297    }
298  }
299  return NULL;  /* string ends out of balance */
300}
301
302
303static const char *max_expand (MatchState *ms, const char *s,
304                                 const char *p, const char *ep) {
305  ptrdiff_t i = 0;  /* counts maximum expand for item */
306  while ((s+i)<ms->src_end && singlematch(uchar(*(s+i)), p, ep))
307    i++;
308  /* keeps trying to match with the maximum repetitions */
309  while (i>=0) {
310    const char *res = match(ms, (s+i), ep+1);
311    if (res) return res;
312    i--;  /* else didn't match; reduce 1 repetition to try again */
313  }
314  return NULL;
315}
316
317
318static const char *min_expand (MatchState *ms, const char *s,
319                                 const char *p, const char *ep) {
320  for (;;) {
321    const char *res = match(ms, s, ep+1);
322    if (res != NULL)
323      return res;
324    else if (s<ms->src_end && singlematch(uchar(*s), p, ep))
325      s++;  /* try with one more repetition */
326    else return NULL;
327  }
328}
329
330
331static const char *start_capture (MatchState *ms, const char *s,
332                                    const char *p, int what) {
333  const char *res;
334  int level = ms->level;
335  if (level >= LUA_MAXCAPTURES) luaL_error(ms->L, "too many captures");
336  ms->capture[level].init = s;
337  ms->capture[level].len = what;
338  ms->level = level+1;
339  if ((res=match(ms, s, p)) == NULL)  /* match failed? */
340    ms->level--;  /* undo capture */
341  return res;
342}
343
344
345static const char *end_capture (MatchState *ms, const char *s,
346                                  const char *p) {
347  int l = capture_to_close(ms);
348  const char *res;
349  ms->capture[l].len = s - ms->capture[l].init;  /* close capture */
350  if ((res = match(ms, s, p)) == NULL)  /* match failed? */
351    ms->capture[l].len = CAP_UNFINISHED;  /* undo capture */
352  return res;
353}
354
355
356static const char *match_capture (MatchState *ms, const char *s, int l) {
357  size_t len;
358  l = check_capture(ms, l);
359  len = ms->capture[l].len;
360  if ((size_t)(ms->src_end-s) >= len &&
361      memcmp(ms->capture[l].init, s, len) == 0)
362    return s+len;
363  else return NULL;
364}
365
366
367static const char *match (MatchState *ms, const char *s, const char *p) {
368  init: /* using goto's to optimize tail recursion */
369  switch (*p) {
370    case '(': {  /* start capture */
371      if (*(p+1) == ')')  /* position capture? */
372        return start_capture(ms, s, p+2, CAP_POSITION);
373      else
374        return start_capture(ms, s, p+1, CAP_UNFINISHED);
375    }
376    case ')': {  /* end capture */
377      return end_capture(ms, s, p+1);
378    }
379    case L_ESC: {
380      switch (*(p+1)) {
381        case 'b': {  /* balanced string? */
382          s = matchbalance(ms, s, p+2);
383          if (s == NULL) return NULL;
384          p+=4; goto init;  /* else return match(ms, s, p+4); */
385        }
386        case 'f': {  /* frontier? */
387          const char *ep; char previous;
388          p += 2;
389          if (*p != '[')
390            luaL_error(ms->L, "missing " LUA_QL("[") " after "
391                               LUA_QL("%%f") " in pattern");
392          ep = classend(ms, p);  /* points to what is next */
393          previous = (s == ms->src_init) ? '\0' : *(s-1);
394          if (matchbracketclass(uchar(previous), p, ep-1) ||
395             !matchbracketclass(uchar(*s), p, ep-1)) return NULL;
396          p=ep; goto init;  /* else return match(ms, s, ep); */
397        }
398        default: {
399          if (isdigit(uchar(*(p+1)))) {  /* capture results (%0-%9)? */
400            s = match_capture(ms, s, uchar(*(p+1)));
401            if (s == NULL) return NULL;
402            p+=2; goto init;  /* else return match(ms, s, p+2) */
403          }
404          goto dflt;  /* case default */
405        }
406      }
407    }
408    case '\0': {  /* end of pattern */
409      return s;  /* match succeeded */
410    }
411    case '$': {
412      if (*(p+1) == '\0')  /* is the `$' the last char in pattern? */
413        return (s == ms->src_end) ? s : NULL;  /* check end of string */
414      else goto dflt;
415    }
416    default: dflt: {  /* it is a pattern item */
417      const char *ep = classend(ms, p);  /* points to what is next */
418      int m = s<ms->src_end && singlematch(uchar(*s), p, ep);
419      switch (*ep) {
420        case '?': {  /* optional */
421          const char *res;
422          if (m && ((res=match(ms, s+1, ep+1)) != NULL))
423            return res;
424          p=ep+1; goto init;  /* else return match(ms, s, ep+1); */
425        }
426        case '*': {  /* 0 or more repetitions */
427          return max_expand(ms, s, p, ep);
428        }
429        case '+': {  /* 1 or more repetitions */
430          return (m ? max_expand(ms, s+1, p, ep) : NULL);
431        }
432        case '-': {  /* 0 or more repetitions (minimum) */
433          return min_expand(ms, s, p, ep);
434        }
435        default: {
436          if (!m) return NULL;
437          s++; p=ep; goto init;  /* else return match(ms, s+1, ep); */
438        }
439      }
440    }
441  }
442}
443
444
445
446static const char *lmemfind (const char *s1, size_t l1,
447                               const char *s2, size_t l2) {
448  if (l2 == 0) return s1;  /* empty strings are everywhere */
449  else if (l2 > l1) return NULL;  /* avoids a negative `l1' */
450  else {
451    const char *init;  /* to search for a `*s2' inside `s1' */
452    l2--;  /* 1st char will be checked by `memchr' */
453    l1 = l1-l2;  /* `s2' cannot be found after that */
454    while (l1 > 0 && (init = (const char *)memchr(s1, *s2, l1)) != NULL) {
455      init++;   /* 1st char is already checked */
456      if (memcmp(init, s2+1, l2) == 0)
457        return init-1;
458      else {  /* correct `l1' and `s1' to try again */
459        l1 -= init-s1;
460        s1 = init;
461      }
462    }
463    return NULL;  /* not found */
464  }
465}
466
467
468static void push_onecapture (MatchState *ms, int i, const char *s,
469                                                    const char *e) {
470  if (i >= ms->level) {
471    if (i == 0)  /* ms->level == 0, too */
472      lua_pushlstring(ms->L, s, e - s);  /* add whole match */
473    else
474      luaL_error(ms->L, "invalid capture index");
475  }
476  else {
477    ptrdiff_t l = ms->capture[i].len;
478    if (l == CAP_UNFINISHED) luaL_error(ms->L, "unfinished capture");
479    if (l == CAP_POSITION)
480      lua_pushinteger(ms->L, ms->capture[i].init - ms->src_init + 1);
481    else
482      lua_pushlstring(ms->L, ms->capture[i].init, l);
483  }
484}
485
486
487static int push_captures (MatchState *ms, const char *s, const char *e) {
488  int i;
489  int nlevels = (ms->level == 0 && s) ? 1 : ms->level;
490  luaL_checkstack(ms->L, nlevels, "too many captures");
491  for (i = 0; i < nlevels; i++)
492    push_onecapture(ms, i, s, e);
493  return nlevels;  /* number of strings pushed */
494}
495
496
497static int str_find_aux (lua_State *L, int find) {
498  size_t l1, l2;
499  const char *s = luaL_checklstring(L, 1, &l1);
500  const char *p = luaL_checklstring(L, 2, &l2);
501  ptrdiff_t init = posrelat(luaL_optinteger(L, 3, 1), l1) - 1;
502  if (init < 0) init = 0;
503  else if ((size_t)(init) > l1) init = (ptrdiff_t)l1;
504  if (find && (lua_toboolean(L, 4) ||  /* explicit request? */
505      strpbrk(p, SPECIALS) == NULL)) {  /* or no special characters? */
506    /* do a plain search */
507    const char *s2 = lmemfind(s+init, l1-init, p, l2);
508    if (s2) {
509      lua_pushinteger(L, s2-s+1);
510      lua_pushinteger(L, s2-s+l2);
511      return 2;
512    }
513  }
514  else {
515    MatchState ms;
516    int anchor = (*p == '^') ? (p++, 1) : 0;
517    const char *s1=s+init;
518    ms.L = L;
519    ms.src_init = s;
520    ms.src_end = s+l1;
521    do {
522      const char *res;
523      ms.level = 0;
524      if ((res=match(&ms, s1, p)) != NULL) {
525        if (find) {
526          lua_pushinteger(L, s1-s+1);  /* start */
527          lua_pushinteger(L, res-s);   /* end */
528          return push_captures(&ms, NULL, 0) + 2;
529        }
530        else
531          return push_captures(&ms, s1, res);
532      }
533    } while (s1++ < ms.src_end && !anchor);
534  }
535  lua_pushnil(L);  /* not found */
536  return 1;
537}
538
539
540static int str_find (lua_State *L) {
541  return str_find_aux(L, 1);
542}
543
544
545static int str_match (lua_State *L) {
546  return str_find_aux(L, 0);
547}
548
549
550static int gmatch_aux (lua_State *L) {
551  MatchState ms;
552  size_t ls;
553  const char *s = lua_tolstring(L, lua_upvalueindex(1), &ls);
554  const char *p = lua_tostring(L, lua_upvalueindex(2));
555  const char *src;
556  ms.L = L;
557  ms.src_init = s;
558  ms.src_end = s+ls;
559  for (src = s + (size_t)lua_tointeger(L, lua_upvalueindex(3));
560       src <= ms.src_end;
561       src++) {
562    const char *e;
563    ms.level = 0;
564    if ((e = match(&ms, src, p)) != NULL) {
565      lua_Integer newstart = e-s;
566      if (e == src) newstart++;  /* empty match? go at least one position */
567      lua_pushinteger(L, newstart);
568      lua_replace(L, lua_upvalueindex(3));
569      return push_captures(&ms, src, e);
570    }
571  }
572  return 0;  /* not found */
573}
574
575
576static int gmatch (lua_State *L) {
577  luaL_checkstring(L, 1);
578  luaL_checkstring(L, 2);
579  lua_settop(L, 2);
580  lua_pushinteger(L, 0);
581  lua_pushcclosure(L, gmatch_aux, 3);
582  return 1;
583}
584
585
586static int gfind_nodef (lua_State *L) {
587  return luaL_error(L, LUA_QL("string.gfind") " was renamed to "
588                       LUA_QL("string.gmatch"));
589}
590
591
592static void add_s (MatchState *ms, luaL_Buffer *b, const char *s,
593                                                   const char *e) {
594  size_t l, i;
595  const char *news = lua_tolstring(ms->L, 3, &l);
596  for (i = 0; i < l; i++) {
597    if (news[i] != L_ESC)
598      luaL_addchar(b, news[i]);
599    else {
600      i++;  /* skip ESC */
601      if (!isdigit(uchar(news[i])))
602        luaL_addchar(b, news[i]);
603      else if (news[i] == '0')
604          luaL_addlstring(b, s, e - s);
605      else {
606        push_onecapture(ms, news[i] - '1', s, e);
607        luaL_addvalue(b);  /* add capture to accumulated result */
608      }
609    }
610  }
611}
612
613
614static void add_value (MatchState *ms, luaL_Buffer *b, const char *s,
615                                                       const char *e) {
616  lua_State *L = ms->L;
617  switch (lua_type(L, 3)) {
618    case LUA_TNUMBER:
619    case LUA_TSTRING: {
620      add_s(ms, b, s, e);
621      return;
622    }
623    case LUA_TFUNCTION: {
624      int n;
625      lua_pushvalue(L, 3);
626      n = push_captures(ms, s, e);
627      lua_call(L, n, 1);
628      break;
629    }
630    case LUA_TTABLE: {
631      push_onecapture(ms, 0, s, e);
632      lua_gettable(L, 3);
633      break;
634    }
635  }
636  if (!lua_toboolean(L, -1)) {  /* nil or false? */
637    lua_pop(L, 1);
638    lua_pushlstring(L, s, e - s);  /* keep original text */
639  }
640  else if (!lua_isstring(L, -1))
641    luaL_error(L, "invalid replacement value (a %s)", luaL_typename(L, -1));
642  luaL_addvalue(b);  /* add result to accumulator */
643}
644
645
646static int str_gsub (lua_State *L) {
647  size_t srcl;
648  const char *src = luaL_checklstring(L, 1, &srcl);
649  const char *p = luaL_checkstring(L, 2);
650  int  tr = lua_type(L, 3);
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_argcheck(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||
657                   tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3,
658                      "string/function/table expected");
659  luaL_buffinit(L, &b);
660  ms.L = L;
661  ms.src_init = src;
662  ms.src_end = src+srcl;
663  while (n < max_s) {
664    const char *e;
665    ms.level = 0;
666    e = match(&ms, src, p);
667    if (e) {
668      n++;
669      add_value(&ms, &b, src, e);
670    }
671    if (e && e>src) /* non empty match? */
672      src = e;  /* skip it */
673    else if (src < ms.src_end)
674      luaL_addchar(&b, *src++);
675    else break;
676    if (anchor) break;
677  }
678  luaL_addlstring(&b, src, ms.src_end-src);
679  luaL_pushresult(&b);
680  lua_pushinteger(L, n);  /* number of substitutions */
681  return 2;
682}
683
684/* }====================================================== */
685
686
687/* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */
688#define MAX_ITEM	512
689/* valid flags in a format specification */
690#define FLAGS	"-+ #0"
691/*
692** maximum size of each format specification (such as '%-099.99d')
693** (+10 accounts for %99.99x plus margin of error)
694*/
695#define MAX_FORMAT	(sizeof(FLAGS) + sizeof(LUA_INTFRMLEN) + 10)
696
697
698static void addquoted (lua_State *L, luaL_Buffer *b, int arg) {
699  size_t l;
700  const char *s = luaL_checklstring(L, arg, &l);
701  luaL_addchar(b, '"');
702  while (l--) {
703    switch (*s) {
704      case '"': case '\\': case '\n': {
705        luaL_addchar(b, '\\');
706        luaL_addchar(b, *s);
707        break;
708      }
709      case '\r': {
710        luaL_addlstring(b, "\\r", 2);
711        break;
712      }
713      case '\0': {
714        luaL_addlstring(b, "\\000", 4);
715        break;
716      }
717      default: {
718        luaL_addchar(b, *s);
719        break;
720      }
721    }
722    s++;
723  }
724  luaL_addchar(b, '"');
725}
726
727static const char *scanformat (lua_State *L, const char *strfrmt, char *form) {
728  const char *p = strfrmt;
729  while (*p != '\0' && strchr(FLAGS, *p) != NULL) p++;  /* skip flags */
730  if ((size_t)(p - strfrmt) >= sizeof(FLAGS))
731    luaL_error(L, "invalid format (repeated flags)");
732  if (isdigit(uchar(*p))) p++;  /* skip width */
733  if (isdigit(uchar(*p))) p++;  /* (2 digits at most) */
734  if (*p == '.') {
735    p++;
736    if (isdigit(uchar(*p))) p++;  /* skip precision */
737    if (isdigit(uchar(*p))) p++;  /* (2 digits at most) */
738  }
739  if (isdigit(uchar(*p)))
740    luaL_error(L, "invalid format (width or precision too long)");
741  *(form++) = '%';
742  strncpy(form, strfrmt, p - strfrmt + 1);
743  form += p - strfrmt + 1;
744  *form = '\0';
745  return p;
746}
747
748
749static void addintlen (char *form) {
750  size_t l = strlen(form);
751  char spec = form[l - 1];
752  strcpy(form + l - 1, LUA_INTFRMLEN);
753  form[l + sizeof(LUA_INTFRMLEN) - 2] = spec;
754  form[l + sizeof(LUA_INTFRMLEN) - 1] = '\0';
755}
756
757
758static int str_format (lua_State *L) {
759  int arg = 1;
760  size_t sfl;
761  const char *strfrmt = luaL_checklstring(L, arg, &sfl);
762  const char *strfrmt_end = strfrmt+sfl;
763  luaL_Buffer b;
764  luaL_buffinit(L, &b);
765  while (strfrmt < strfrmt_end) {
766    if (*strfrmt != L_ESC)
767      luaL_addchar(&b, *strfrmt++);
768    else if (*++strfrmt == L_ESC)
769      luaL_addchar(&b, *strfrmt++);  /* %% */
770    else { /* format item */
771      char form[MAX_FORMAT];  /* to store the format (`%...') */
772      char buff[MAX_ITEM];  /* to store the formatted item */
773      arg++;
774      strfrmt = scanformat(L, strfrmt, form);
775      switch (*strfrmt++) {
776        case 'c': {
777          sprintf(buff, form, (int)luaL_checknumber(L, arg));
778          break;
779        }
780        case 'd':  case 'i': {
781          addintlen(form);
782          sprintf(buff, form, (LUA_INTFRM_T)luaL_checknumber(L, arg));
783          break;
784        }
785        case 'o':  case 'u':  case 'x':  case 'X': {
786          addintlen(form);
787          sprintf(buff, form, (unsigned LUA_INTFRM_T)luaL_checknumber(L, arg));
788          break;
789        }
790        case 'e':  case 'E': case 'f':
791        case 'g': case 'G': {
792          sprintf(buff, form, (double)luaL_checknumber(L, arg));
793          break;
794        }
795        case 'q': {
796          addquoted(L, &b, arg);
797          continue;  /* skip the 'addsize' at the end */
798        }
799        case 's': {
800          size_t l;
801          const char *s = luaL_checklstring(L, arg, &l);
802          if (!strchr(form, '.') && l >= 100) {
803            /* no precision and string is too long to be formatted;
804               keep original string */
805            lua_pushvalue(L, arg);
806            luaL_addvalue(&b);
807            continue;  /* skip the `addsize' at the end */
808          }
809          else {
810            sprintf(buff, form, s);
811            break;
812          }
813        }
814        default: {  /* also treat cases `pnLlh' */
815          return luaL_error(L, "invalid option " LUA_QL("%%%c") " to "
816                               LUA_QL("format"), *(strfrmt - 1));
817        }
818      }
819      luaL_addlstring(&b, buff, strlen(buff));
820    }
821  }
822  luaL_pushresult(&b);
823  return 1;
824}
825
826
827static const luaL_Reg strlib[] = {
828  {"byte", str_byte},
829  {"char", str_char},
830  {"dump", str_dump},
831  {"find", str_find},
832  {"format", str_format},
833  {"gfind", gfind_nodef},
834  {"gmatch", gmatch},
835  {"gsub", str_gsub},
836  {"len", str_len},
837  {"lower", str_lower},
838  {"match", str_match},
839  {"rep", str_rep},
840  {"reverse", str_reverse},
841  {"sub", str_sub},
842  {"upper", str_upper},
843  {NULL, NULL}
844};
845
846
847static void createmetatable (lua_State *L) {
848  lua_createtable(L, 0, 1);  /* create metatable for strings */
849  lua_pushliteral(L, "");  /* dummy string */
850  lua_pushvalue(L, -2);
851  lua_setmetatable(L, -2);  /* set string metatable */
852  lua_pop(L, 1);  /* pop dummy string */
853  lua_pushvalue(L, -2);  /* string library... */
854  lua_setfield(L, -2, "__index");  /* ...is the __index metamethod */
855  lua_pop(L, 1);  /* pop metatable */
856}
857
858
859/*
860** Open string library
861*/
862LUALIB_API int luaopen_string (lua_State *L) {
863  luaL_register(L, LUA_STRLIBNAME, strlib);
864#if defined(LUA_COMPAT_GFIND)
865  lua_getfield(L, -1, "gmatch");
866  lua_setfield(L, -2, "gfind");
867#endif
868  createmetatable(L);
869  return 1;
870}
871
872