kernel/fs/zfs/lua/lstrlib.c

   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 <sys/ctype.h>
   9 #include <sys/zfs_context.h>
  10
  11 #define lstrlib_c
  12 #define LUA_LIB
  13
  14 #include "lua.h"
  15
  16 #include "lauxlib.h"
  17 #include "lualib.h"
  18
  19
  20 /*
  21 ** maximum number of captures that a pattern can do during
  22 ** pattern-matching. This limit is arbitrary.
  23 */
  24 #if !defined(LUA_MAXCAPTURES)
  25 #define LUA_MAXCAPTURES         32
  26 #endif
  27
  28
  29 /* macro to `unsign' a character */
  30 #define uchar(c)        ((unsigned char)(c))
  31
  32 /*
  33  * PATCHED: add missing character macros.
  34  */
  35 #define tolower(C)      (((C) >= 'A' && (C) <= 'Z') ? (C) - 'A' + 'a' : (C))
  36 #define toupper(C)      (((C) >= 'a' && (C) <= 'z') ? (C) - 'a' + 'A': (C))
  37 #define isgraph(C)      ((C) >= 0x21 && (C) <= 0x7E)
  38 #define ispunct(C)      (((C) >= 0x21 && (C) <= 0x2F) || \
  39     ((C) >= 0x3A && (C) <= 0x40) || \
  40     ((C) >= 0x5B && (C) <= 0x60) || \
  41     ((C) >= 0x7B && (C) <= 0x7E))
  42
  43 /*
  44  * The provided version of sprintf returns a char *, but str_format expects
  45  * it to return the number of characters printed. This version has the expected
  46  * behavior.
  47  */
  48 static size_t str_sprintf(char *buf, const char *fmt, ...) {
  49   va_list args;
  50   size_t len;
  51
  52   va_start(args, fmt);
  53   len = vsnprintf(buf, INT_MAX, fmt, args);
  54   va_end(args);
  55
  56   return len;
  57 }
  58
  59
  60 static int str_len (lua_State *L) {
  61   size_t l;
  62   luaL_checklstring(L, 1, &l);
  63   lua_pushinteger(L, (lua_Integer)l);
  64   return 1;
  65 }
  66
  67
  68 /* translate a relative string position: negative means back from end */
  69 static size_t posrelat (ptrdiff_t pos, size_t len) {
  70   if (pos >= 0) return (size_t)pos;
  71   else if (0u - (size_t)pos > len) return 0;
  72   else return len - ((size_t)-pos) + 1;
  73 }
  74
  75
  76 static int str_sub (lua_State *L) {
  77   size_t l;
  78   const char *s = luaL_checklstring(L, 1, &l);
  79   size_t start = posrelat(luaL_checkinteger(L, 2), l);
  80   size_t end = posrelat(luaL_optinteger(L, 3, -1), l);
  81   if (start < 1) start = 1;
  82   if (end > l) end = l;
  83   if (start <= end)
  84     lua_pushlstring(L, s + start - 1, end - start + 1);
  85   else lua_pushliteral(L, "");
  86   return 1;
  87 }
  88
  89
  90 static int str_reverse (lua_State *L) {
  91   size_t l, i;
  92   luaL_Buffer b;
  93   const char *s = luaL_checklstring(L, 1, &l);
  94   char *p = luaL_buffinitsize(L, &b, l);
  95   for (i = 0; i < l; i++)
  96     p[i] = s[l - i - 1];
  97   luaL_pushresultsize(&b, l);
  98   return 1;
  99 }
 100
 101
 102 static int str_lower (lua_State *L) {
 103   size_t l;
 104   size_t i;
 105   luaL_Buffer b;
 106   const char *s = luaL_checklstring(L, 1, &l);
 107   char *p = luaL_buffinitsize(L, &b, l);
 108   for (i=0; i<l; i++)
 109     p[i] = tolower(uchar(s[i]));
 110   luaL_pushresultsize(&b, l);
 111   return 1;
 112 }
 113
 114
 115 static int str_upper (lua_State *L) {
 116   size_t l;
 117   size_t i;
 118   luaL_Buffer b;
 119   const char *s = luaL_checklstring(L, 1, &l);
 120   char *p = luaL_buffinitsize(L, &b, l);
 121   for (i=0; i<l; i++)
 122     p[i] = toupper(uchar(s[i]));
 123   luaL_pushresultsize(&b, l);
 124   return 1;
 125 }
 126
 127
 128 /* reasonable limit to avoid arithmetic overflow */
 129 #define MAXSIZE         ((~(size_t)0) >> 1)
 130
 131 static int str_rep (lua_State *L) {
 132   size_t l, lsep;
 133   const char *s = luaL_checklstring(L, 1, &l);
 134   int n = luaL_checkint(L, 2);
 135   const char *sep = luaL_optlstring(L, 3, "", &lsep);
 136   if (n <= 0) lua_pushliteral(L, "");
 137   else if (l + lsep < l || l + lsep >= MAXSIZE / n)  /* may overflow? */
 138     return luaL_error(L, "resulting string too large");
 139   else {
 140     size_t totallen = n * l + (n - 1) * lsep;
 141     luaL_Buffer b;
 142     char *p = luaL_buffinitsize(L, &b, totallen);
 143     while (n-- > 1) {  /* first n-1 copies (followed by separator) */
 144       memcpy(p, s, l * sizeof(char)); p += l;
 145       if (lsep > 0) {  /* avoid empty 'memcpy' (may be expensive) */
 146         memcpy(p, sep, lsep * sizeof(char)); p += lsep;
 147       }
 148     }
 149     memcpy(p, s, l * sizeof(char));  /* last copy (not followed by separator) */
 150     luaL_pushresultsize(&b, totallen);
 151   }
 152   return 1;
 153 }
 154
 155
 156 static int str_byte (lua_State *L) {
 157   size_t l;
 158   const char *s = luaL_checklstring(L, 1, &l);
 159   size_t posi = posrelat(luaL_optinteger(L, 2, 1), l);
 160   size_t pose = posrelat(luaL_optinteger(L, 3, posi), l);
 161   int n, i;
 162   if (posi < 1) posi = 1;
 163   if (pose > l) pose = l;
 164   if (posi > pose) return 0;  /* empty interval; return no values */
 165   n = (int)(pose -  posi + 1);
 166   if (posi + n <= pose)  /* (size_t -> int) overflow? */
 167     return luaL_error(L, "string slice too long");
 168   luaL_checkstack(L, n, "string slice too long");
 169   for (i=0; i<n; i++)
 170     lua_pushinteger(L, uchar(s[posi+i-1]));
 171   return n;
 172 }
 173
 174
 175 static int str_char (lua_State *L) {
 176   int n = lua_gettop(L);  /* number of arguments */
 177   int i;
 178   luaL_Buffer b;
 179   char *p = luaL_buffinitsize(L, &b, n);
 180   for (i=1; i<=n; i++) {
 181     int c = luaL_checkint(L, i);
 182     luaL_argcheck(L, uchar(c) == c, i, "value out of range");
 183     p[i - 1] = uchar(c);
 184   }
 185   luaL_pushresultsize(&b, n);
 186   return 1;
 187 }
 188
 189
 190 static int writer (lua_State *L, const void* b, size_t size, void* B) {
 191   (void)L;
 192   luaL_addlstring((luaL_Buffer*) B, (const char *)b, size);
 193   return 0;
 194 }
 195
 196
 197 static int str_dump (lua_State *L) {
 198   luaL_Buffer b;
 199   luaL_checktype(L, 1, LUA_TFUNCTION);
 200   lua_settop(L, 1);
 201   luaL_buffinit(L,&b);
 202   if (lua_dump(L, writer, &b) != 0)
 203     return luaL_error(L, "unable to dump given function");
 204   luaL_pushresult(&b);
 205   return 1;
 206 }
 207
 208
 209
 210 /*
 211 ** {======================================================
 212 ** PATTERN MATCHING
 213 ** =======================================================
 214 */
 215
 216
 217 #define CAP_UNFINISHED  (-1)
 218 #define CAP_POSITION    (-2)
 219
 220
 221 typedef struct MatchState {
 222   int matchdepth;  /* control for recursive depth (to avoid C stack overflow) */
 223   const char *src_init;  /* init of source string */
 224   const char *src_end;  /* end ('\0') of source string */
 225   const char *p_end;  /* end ('\0') of pattern */
 226   lua_State *L;
 227   int level;  /* total number of captures (finished or unfinished) */
 228   struct {
 229     const char *init;
 230     ptrdiff_t len;
 231   } capture[LUA_MAXCAPTURES];
 232 } MatchState;
 233
 234
 235 /* recursive function */
 236 static const char *match (MatchState *ms, const char *s, const char *p);
 237
 238
 239 /* maximum recursion depth for 'match' */
 240 #if !defined(MAXCCALLS)
 241 #define MAXCCALLS       200
 242 #endif
 243
 244
 245 #define L_ESC           '%'
 246 #define SPECIALS        "^$*+?.([%-"
 247
 248
 249 static int check_capture (MatchState *ms, int l) {
 250   l -= '1';
 251   if (l < 0 || l >= ms->level || ms->capture[l].len == CAP_UNFINISHED)
 252     return luaL_error(ms->L, "invalid capture index %%%d", l + 1);
 253   return l;
 254 }
 255
 256
 257 static int capture_to_close (MatchState *ms) {
 258   int level = ms->level;
 259   for (level--; level>=0; level--)
 260     if (ms->capture[level].len == CAP_UNFINISHED) return level;
 261   return luaL_error(ms->L, "invalid pattern capture");
 262 }
 263
 264
 265 static const char *classend (MatchState *ms, const char *p) {
 266   switch (*p++) {
 267     case L_ESC: {
 268       if (p == ms->p_end)
 269         luaL_error(ms->L, "malformed pattern (ends with " LUA_QL("%%") ")");
 270       return p+1;
 271     }
 272     case '[': {
 273       if (*p == '^') p++;
 274       do {  /* look for a `]' */
 275         if (p == ms->p_end)
 276           luaL_error(ms->L, "malformed pattern (missing " LUA_QL("]") ")");
 277         if (*(p++) == L_ESC && p < ms->p_end)
 278           p++;  /* skip escapes (e.g. `%]') */
 279       } while (*p != ']');
 280       return p+1;
 281     }
 282     default: {
 283       return p;
 284     }
 285   }
 286 }
 287
 288
 289 static int
 290 iscntrl(int c)
 291 {
 292         return ((c < 0x20) || (c == 0x7f));
 293 }
 294
 295
 296 static int match_class (int c, int cl) {
 297   int res;
 298   switch (tolower(cl)) {
 299     case 'a' : res = isalpha(c); break;
 300     case 'c' : res = iscntrl(c); break;
 301     case 'd' : res = isdigit(c); break;
 302     case 'g' : res = isgraph(c); break;
 303     case 'l' : res = islower(c); break;
 304     case 'p' : res = ispunct(c); break;
 305     case 's' : res = isspace(c); break;
 306     case 'u' : res = isupper(c); break;
 307     case 'w' : res = isalnum(c); break;
 308     case 'x' : res = isxdigit(c); break;
 309     case 'z' : res = (c == 0); break;  /* deprecated option */
 310     default: return (cl == c);
 311   }
 312   return (islower(cl) ? res : !res);
 313 }
 314
 315
 316 static int matchbracketclass (int c, const char *p, const char *ec) {
 317   int sig = 1;
 318   if (*(p+1) == '^') {
 319     sig = 0;
 320     p++;  /* skip the `^' */
 321   }
 322   while (++p < ec) {
 323     if (*p == L_ESC) {
 324       p++;
 325       if (match_class(c, uchar(*p)))
 326         return sig;
 327     }
 328     else if ((*(p+1) == '-') && (p+2 < ec)) {
 329       p+=2;
 330       if (uchar(*(p-2)) <= c && c <= uchar(*p))
 331         return sig;
 332     }
 333     else if (uchar(*p) == c) return sig;
 334   }
 335   return !sig;
 336 }
 337
 338
 339 static int singlematch (MatchState *ms, const char *s, const char *p,
 340                         const char *ep) {
 341   if (s >= ms->src_end)
 342     return 0;
 343   else {
 344     int c = uchar(*s);
 345     switch (*p) {
 346       case '.': return 1;  /* matches any char */
 347       case L_ESC: return match_class(c, uchar(*(p+1)));
 348       case '[': return matchbracketclass(c, p, ep-1);
 349       default:  return (uchar(*p) == c);
 350     }
 351   }
 352 }
 353
 354
 355 static const char *matchbalance (MatchState *ms, const char *s,
 356                                    const char *p) {
 357   if (p >= ms->p_end - 1)
 358     luaL_error(ms->L, "malformed pattern "
 359                       "(missing arguments to " LUA_QL("%%b") ")");
 360   if (*s != *p) return NULL;
 361   else {
 362     int b = *p;
 363     int e = *(p+1);
 364     int cont = 1;
 365     while (++s < ms->src_end) {
 366       if (*s == e) {
 367         if (--cont == 0) return s+1;
 368       }
 369       else if (*s == b) cont++;
 370     }
 371   }
 372   return NULL;  /* string ends out of balance */
 373 }
 374
 375
 376 static const char *max_expand (MatchState *ms, const char *s,
 377                                  const char *p, const char *ep) {
 378   ptrdiff_t i = 0;  /* counts maximum expand for item */
 379   while (singlematch(ms, s + i, p, ep))
 380     i++;
 381   /* keeps trying to match with the maximum repetitions */
 382   while (i>=0) {
 383     const char *res = match(ms, (s+i), ep+1);
 384     if (res) return res;
 385     i--;  /* else didn't match; reduce 1 repetition to try again */
 386   }
 387   return NULL;
 388 }
 389
 390
 391 static const char *min_expand (MatchState *ms, const char *s,
 392                                  const char *p, const char *ep) {
 393   for (;;) {
 394     const char *res = match(ms, s, ep+1);
 395     if (res != NULL)
 396       return res;
 397     else if (singlematch(ms, s, p, ep))
 398       s++;  /* try with one more repetition */
 399     else return NULL;
 400   }
 401 }
 402
 403
 404 static const char *start_capture (MatchState *ms, const char *s,
 405                                     const char *p, int what) {
 406   const char *res;
 407   int level = ms->level;
 408   if (level >= LUA_MAXCAPTURES) luaL_error(ms->L, "too many captures");
 409   ms->capture[level].init = s;
 410   ms->capture[level].len = what;
 411   ms->level = level+1;
 412   if ((res=match(ms, s, p)) == NULL)  /* match failed? */
 413     ms->level--;  /* undo capture */
 414   return res;
 415 }
 416
 417
 418 static const char *end_capture (MatchState *ms, const char *s,
 419                                   const char *p) {
 420   int l = capture_to_close(ms);
 421   const char *res;
 422   ms->capture[l].len = s - ms->capture[l].init;  /* close capture */
 423   if ((res = match(ms, s, p)) == NULL)  /* match failed? */
 424     ms->capture[l].len = CAP_UNFINISHED;  /* undo capture */
 425   return res;
 426 }
 427
 428
 429 static const char *match_capture (MatchState *ms, const char *s, int l) {
 430   size_t len;
 431   l = check_capture(ms, l);
 432   len = ms->capture[l].len;
 433   if ((size_t)(ms->src_end-s) >= len &&
 434       memcmp(ms->capture[l].init, s, len) == 0)
 435     return s+len;
 436   else return NULL;
 437 }
 438
 439
 440 static const char *match (MatchState *ms, const char *s, const char *p) {
 441   if (ms->matchdepth-- == 0)
 442     luaL_error(ms->L, "pattern too complex");
 443   init: /* using goto's to optimize tail recursion */
 444   if (p != ms->p_end) {  /* end of pattern? */
 445     switch (*p) {
 446       case '(': {  /* start capture */
 447         if (*(p + 1) == ')')  /* position capture? */
 448           s = start_capture(ms, s, p + 2, CAP_POSITION);
 449         else
 450           s = start_capture(ms, s, p + 1, CAP_UNFINISHED);
 451         break;
 452       }
 453       case ')': {  /* end capture */
 454         s = end_capture(ms, s, p + 1);
 455         break;
 456       }
 457       case '$': {
 458         if ((p + 1) != ms->p_end)  /* is the `$' the last char in pattern? */
 459           goto dflt;  /* no; go to default */
 460         s = (s == ms->src_end) ? s : NULL;  /* check end of string */
 461         break;
 462       }
 463       case L_ESC: {  /* escaped sequences not in the format class[*+?-]? */
 464         switch (*(p + 1)) {
 465           case 'b': {  /* balanced string? */
 466             s = matchbalance(ms, s, p + 2);
 467             if (s != NULL) {
 468               p += 4; goto init;  /* return match(ms, s, p + 4); */
 469             }  /* else fail (s == NULL) */
 470             break;
 471           }
 472           case 'f': {  /* frontier? */
 473             const char *ep; char previous;
 474             p += 2;
 475             if (*p != '[')
 476               luaL_error(ms->L, "missing " LUA_QL("[") " after "
 477                                  LUA_QL("%%f") " in pattern");
 478             ep = classend(ms, p);  /* points to what is next */
 479             previous = (s == ms->src_init) ? '\0' : *(s - 1);
 480             if (!matchbracketclass(uchar(previous), p, ep - 1) &&
 481                matchbracketclass(uchar(*s), p, ep - 1)) {
 482               p = ep; goto init;  /* return match(ms, s, ep); */
 483             }
 484             s = NULL;  /* match failed */
 485             break;
 486           }
 487           case '0': case '1': case '2': case '3':
 488           case '4': case '5': case '6': case '7':
 489           case '8': case '9': {  /* capture results (%0-%9)? */
 490             s = match_capture(ms, s, uchar(*(p + 1)));
 491             if (s != NULL) {
 492               p += 2; goto init;  /* return match(ms, s, p + 2) */
 493             }
 494             break;
 495           }
 496           default: goto dflt;
 497         }
 498         break;
 499       }
 500       default: dflt: {  /* pattern class plus optional suffix */
 501         const char *ep = classend(ms, p);  /* points to optional suffix */
 502         /* does not match at least once? */
 503         if (!singlematch(ms, s, p, ep)) {
 504           if (*ep == '*' || *ep == '?' || *ep == '-') {  /* accept empty? */
 505             p = ep + 1; goto init;  /* return match(ms, s, ep + 1); */
 506           }
 507           else  /* '+' or no suffix */
 508             s = NULL;  /* fail */
 509         }
 510         else {  /* matched once */
 511           switch (*ep) {  /* handle optional suffix */
 512             case '?': {  /* optional */
 513               const char *res;
 514               if ((res = match(ms, s + 1, ep + 1)) != NULL)
 515                 s = res;
 516               else {
 517                 p = ep + 1; goto init;  /* else return match(ms, s, ep + 1); */
 518               }
 519               break;
 520             }
 521             case '+':  /* 1 or more repetitions */
 522               s++;  /* 1 match already done */
 523               /* FALLTHROUGH */
 524             case '*':  /* 0 or more repetitions */
 525               s = max_expand(ms, s, p, ep);
 526               break;
 527             case '-':  /* 0 or more repetitions (minimum) */
 528               s = min_expand(ms, s, p, ep);
 529               break;
 530             default:  /* no suffix */
 531               s++; p = ep; goto init;  /* return match(ms, s + 1, ep); */
 532           }
 533         }
 534         break;
 535       }
 536     }
 537   }
 538   ms->matchdepth++;
 539   return s;
 540 }
 541
 542
 543
 544 static const char *lmemfind (const char *s1, size_t l1,
 545                                const char *s2, size_t l2) {
 546   if (l2 == 0) return s1;  /* empty strings are everywhere */
 547   else if (l2 > l1) return NULL;  /* avoids a negative `l1' */
 548   else {
 549     const char *init;  /* to search for a `*s2' inside `s1' */
 550     l2--;  /* 1st char will be checked by `memchr' */
 551     l1 = l1-l2;  /* `s2' cannot be found after that */
 552     while (l1 > 0 && (init = (const char *)memchr(s1, *s2, l1)) != NULL) {
 553       init++;   /* 1st char is already checked */
 554       if (memcmp(init, s2+1, l2) == 0)
 555         return init-1;
 556       else {  /* correct `l1' and `s1' to try again */
 557         l1 -= init-s1;
 558         s1 = init;
 559       }
 560     }
 561     return NULL;  /* not found */
 562   }
 563 }
 564
 565
 566 static void push_onecapture (MatchState *ms, int i, const char *s,
 567                                                     const char *e) {
 568   if (i >= ms->level) {
 569     if (i == 0)  /* ms->level == 0, too */
 570       lua_pushlstring(ms->L, s, e - s);  /* add whole match */
 571     else
 572       luaL_error(ms->L, "invalid capture index");
 573   }
 574   else {
 575     ptrdiff_t l = ms->capture[i].len;
 576     if (l == CAP_UNFINISHED) luaL_error(ms->L, "unfinished capture");
 577     if (l == CAP_POSITION)
 578       lua_pushinteger(ms->L, ms->capture[i].init - ms->src_init + 1);
 579     else
 580       lua_pushlstring(ms->L, ms->capture[i].init, l);
 581   }
 582 }
 583
 584
 585 static int push_captures (MatchState *ms, const char *s, const char *e) {
 586   int i;
 587   int nlevels = (ms->level == 0 && s) ? 1 : ms->level;
 588   luaL_checkstack(ms->L, nlevels, "too many captures");
 589   for (i = 0; i < nlevels; i++)
 590     push_onecapture(ms, i, s, e);
 591   return nlevels;  /* number of strings pushed */
 592 }
 593
 594
 595 /* check whether pattern has no special characters */
 596 static int nospecials (const char *p, size_t l) {
 597   size_t upto = 0;
 598   do {
 599     if (strpbrk(p + upto, SPECIALS))
 600       return 0;  /* pattern has a special character */
 601     upto += strlen(p + upto) + 1;  /* may have more after \0 */
 602   } while (upto <= l);
 603   return 1;  /* no special chars found */
 604 }
 605
 606
 607 static int str_find_aux (lua_State *L, int find) {
 608   size_t ls, lp;
 609   const char *s = luaL_checklstring(L, 1, &ls);
 610   const char *p = luaL_checklstring(L, 2, &lp);
 611   size_t init = posrelat(luaL_optinteger(L, 3, 1), ls);
 612   if (init < 1) init = 1;
 613   else if (init > ls + 1) {  /* start after string's end? */
 614     lua_pushnil(L);  /* cannot find anything */
 615     return 1;
 616   }
 617   /* explicit request or no special characters? */
 618   if (find && (lua_toboolean(L, 4) || nospecials(p, lp))) {
 619     /* do a plain search */
 620     const char *s2 = lmemfind(s + init - 1, ls - init + 1, p, lp);
 621     if (s2) {
 622       lua_pushinteger(L, s2 - s + 1);
 623       lua_pushinteger(L, s2 - s + lp);
 624       return 2;
 625     }
 626   }
 627   else {
 628     MatchState ms;
 629     const char *s1 = s + init - 1;
 630     int anchor = (*p == '^');
 631     if (anchor) {
 632       p++; lp--;  /* skip anchor character */
 633     }
 634     ms.L = L;
 635     ms.matchdepth = MAXCCALLS;
 636     ms.src_init = s;
 637     ms.src_end = s + ls;
 638     ms.p_end = p + lp;
 639     do {
 640       const char *res;
 641       ms.level = 0;
 642       lua_assert(ms.matchdepth == MAXCCALLS);
 643       if ((res=match(&ms, s1, p)) != NULL) {
 644         if (find) {
 645           lua_pushinteger(L, s1 - s + 1);  /* start */
 646           lua_pushinteger(L, res - s);   /* end */
 647           return push_captures(&ms, NULL, 0) + 2;
 648         }
 649         else
 650           return push_captures(&ms, s1, res);
 651       }
 652     } while (s1++ < ms.src_end && !anchor);
 653   }
 654   lua_pushnil(L);  /* not found */
 655   return 1;
 656 }
 657
 658
 659 static int str_find (lua_State *L) {
 660   return str_find_aux(L, 1);
 661 }
 662
 663
 664 static int str_match (lua_State *L) {
 665   return str_find_aux(L, 0);
 666 }
 667
 668
 669 static int gmatch_aux (lua_State *L) {
 670   MatchState ms;
 671   size_t ls, lp;
 672   const char *s = lua_tolstring(L, lua_upvalueindex(1), &ls);
 673   const char *p = lua_tolstring(L, lua_upvalueindex(2), &lp);
 674   const char *src;
 675   ms.L = L;
 676   ms.matchdepth = MAXCCALLS;
 677   ms.src_init = s;
 678   ms.src_end = s+ls;
 679   ms.p_end = p + lp;
 680   for (src = s + (size_t)lua_tointeger(L, lua_upvalueindex(3));
 681        src <= ms.src_end;
 682        src++) {
 683     const char *e;
 684     ms.level = 0;
 685     lua_assert(ms.matchdepth == MAXCCALLS);
 686     if ((e = match(&ms, src, p)) != NULL) {
 687       lua_Integer newstart = e-s;
 688       if (e == src) newstart++;  /* empty match? go at least one position */
 689       lua_pushinteger(L, newstart);
 690       lua_replace(L, lua_upvalueindex(3));
 691       return push_captures(&ms, src, e);
 692     }
 693   }
 694   return 0;  /* not found */
 695 }
 696
 697
 698 static int str_gmatch (lua_State *L) {
 699   luaL_checkstring(L, 1);
 700   luaL_checkstring(L, 2);
 701   lua_settop(L, 2);
 702   lua_pushinteger(L, 0);
 703   lua_pushcclosure(L, gmatch_aux, 3);
 704   return 1;
 705 }
 706
 707
 708 static void add_s (MatchState *ms, luaL_Buffer *b, const char *s,
 709                                                    const char *e) {
 710   size_t l, i;
 711   const char *news = lua_tolstring(ms->L, 3, &l);
 712   for (i = 0; i < l; i++) {
 713     if (news[i] != L_ESC)
 714       luaL_addchar(b, news[i]);
 715     else {
 716       i++;  /* skip ESC */
 717       if (!isdigit(uchar(news[i]))) {
 718         if (news[i] != L_ESC)
 719           luaL_error(ms->L, "invalid use of " LUA_QL("%c")
 720                            " in replacement string", L_ESC);
 721         luaL_addchar(b, news[i]);
 722       }
 723       else if (news[i] == '0')
 724           luaL_addlstring(b, s, e - s);
 725       else {
 726         push_onecapture(ms, news[i] - '1', s, e);
 727         luaL_addvalue(b);  /* add capture to accumulated result */
 728       }
 729     }
 730   }
 731 }
 732
 733
 734 static void add_value (MatchState *ms, luaL_Buffer *b, const char *s,
 735                                        const char *e, int tr) {
 736   lua_State *L = ms->L;
 737   switch (tr) {
 738     case LUA_TFUNCTION: {
 739       int n;
 740       lua_pushvalue(L, 3);
 741       n = push_captures(ms, s, e);
 742       lua_call(L, n, 1);
 743       break;
 744     }
 745     case LUA_TTABLE: {
 746       push_onecapture(ms, 0, s, e);
 747       lua_gettable(L, 3);
 748       break;
 749     }
 750     default: {  /* LUA_TNUMBER or LUA_TSTRING */
 751       add_s(ms, b, s, e);
 752       return;
 753     }
 754   }
 755   if (!lua_toboolean(L, -1)) {  /* nil or false? */
 756     lua_pop(L, 1);
 757     lua_pushlstring(L, s, e - s);  /* keep original text */
 758   }
 759   else if (!lua_isstring(L, -1))
 760     luaL_error(L, "invalid replacement value (a %s)", luaL_typename(L, -1));
 761   luaL_addvalue(b);  /* add result to accumulator */
 762 }
 763
 764
 765 static int str_gsub (lua_State *L) {
 766   size_t srcl, lp;
 767   const char *src = luaL_checklstring(L, 1, &srcl);
 768   const char *p = luaL_checklstring(L, 2, &lp);
 769   int tr = lua_type(L, 3);
 770   size_t max_s = luaL_optinteger(L, 4, srcl+1);
 771   int anchor = (*p == '^');
 772   size_t n = 0;
 773   MatchState ms;
 774   luaL_Buffer b;
 775   luaL_argcheck(L, tr == LUA_TNUMBER || tr == LUA_TSTRING ||
 776                    tr == LUA_TFUNCTION || tr == LUA_TTABLE, 3,
 777                       "string/function/table expected");
 778   luaL_buffinit(L, &b);
 779   if (anchor) {
 780     p++; lp--;  /* skip anchor character */
 781   }
 782   ms.L = L;
 783   ms.matchdepth = MAXCCALLS;
 784   ms.src_init = src;
 785   ms.src_end = src+srcl;
 786   ms.p_end = p + lp;
 787   while (n < max_s) {
 788     const char *e;
 789     ms.level = 0;
 790     lua_assert(ms.matchdepth == MAXCCALLS);
 791     e = match(&ms, src, p);
 792     if (e) {
 793       n++;
 794       add_value(&ms, &b, src, e, tr);
 795     }
 796     if (e && e>src) /* non empty match? */
 797       src = e;  /* skip it */
 798     else if (src < ms.src_end)
 799       luaL_addchar(&b, *src++);
 800     else break;
 801     if (anchor) break;
 802   }
 803   luaL_addlstring(&b, src, ms.src_end-src);
 804   luaL_pushresult(&b);
 805   lua_pushinteger(L, n);  /* number of substitutions */
 806   return 2;
 807 }
 808
 809 /* }====================================================== */
 810
 811
 812
 813 /*
 814 ** {======================================================
 815 ** STRING FORMAT
 816 ** =======================================================
 817 */
 818
 819 /*
 820 ** LUA_INTFRMLEN is the length modifier for integer conversions in
 821 ** 'string.format'; LUA_INTFRM_T is the integer type corresponding to
 822 ** the previous length
 823 */
 824 #if !defined(LUA_INTFRMLEN)     /* { */
 825 #if defined(LUA_USE_LONGLONG)
 826
 827 #define LUA_INTFRMLEN           "ll"
 828 #define LUA_INTFRM_T            long long
 829
 830 #else
 831
 832 #define LUA_INTFRMLEN           "l"
 833 #define LUA_INTFRM_T            long
 834
 835 #endif
 836 #endif                          /* } */
 837
 838
 839 /*
 840 ** LUA_FLTFRMLEN is the length modifier for float conversions in
 841 ** 'string.format'; LUA_FLTFRM_T is the float type corresponding to
 842 ** the previous length
 843 */
 844 #if !defined(LUA_FLTFRMLEN)
 845
 846 #define LUA_FLTFRMLEN           ""
 847 #define LUA_FLTFRM_T            double
 848
 849 #endif
 850
 851
 852 /* maximum size of each formatted item (> len(format('%99.99f', -1e308))) */
 853 #define MAX_ITEM        512
 854 /* valid flags in a format specification */
 855 #define FLAGS   "-+ #0"
 856 /*
 857 ** maximum size of each format specification (such as '%-099.99d')
 858 ** (+10 accounts for %99.99x plus margin of error)
 859 */
 860 #define MAX_FORMAT      (sizeof(FLAGS) + sizeof(LUA_INTFRMLEN) + 10)
 861
 862
 863 static void addquoted (lua_State *L, luaL_Buffer *b, int arg) {
 864   size_t l;
 865   const char *s = luaL_checklstring(L, arg, &l);
 866   luaL_addchar(b, '"');
 867   while (l--) {
 868     if (*s == '"' || *s == '\\' || *s == '\n') {
 869       luaL_addchar(b, '\\');
 870       luaL_addchar(b, *s);
 871     }
 872     else if (*s == '\0' || iscntrl(uchar(*s))) {
 873       char buff[10];
 874       if (!isdigit(uchar(*(s+1))))
 875         sprintf(buff, "\\%d", (int)uchar(*s));
 876       else
 877         sprintf(buff, "\\%03d", (int)uchar(*s));
 878       luaL_addstring(b, buff);
 879     }
 880     else
 881       luaL_addchar(b, *s);
 882     s++;
 883   }
 884   luaL_addchar(b, '"');
 885 }
 886
 887 static const char *scanformat (lua_State *L, const char *strfrmt, char *form) {
 888   const char *p = strfrmt;
 889   while (*p != '\0' && strchr(FLAGS, *p) != NULL) p++;  /* skip flags */
 890   if ((size_t)(p - strfrmt) >= sizeof(FLAGS)/sizeof(char))
 891     luaL_error(L, "invalid format (repeated flags)");
 892   if (isdigit(uchar(*p))) p++;  /* skip width */
 893   if (isdigit(uchar(*p))) p++;  /* (2 digits at most) */
 894   if (*p == '.') {
 895     p++;
 896     if (isdigit(uchar(*p))) p++;  /* skip precision */
 897     if (isdigit(uchar(*p))) p++;  /* (2 digits at most) */
 898   }
 899   if (isdigit(uchar(*p)))
 900     luaL_error(L, "invalid format (width or precision too long)");
 901   *(form++) = '%';
 902   memcpy(form, strfrmt, (p - strfrmt + 1) * sizeof(char));
 903   form += p - strfrmt + 1;
 904   *form = '\0';
 905   return p;
 906 }
 907
 908
 909 /*
 910 ** add length modifier into formats
 911 */
 912 static void addlenmod (char *form, const char *lenmod) {
 913   size_t l = strlen(form);
 914   size_t lm = strlen(lenmod);
 915   char spec = form[l - 1];
 916   strcpy(form + l - 1, lenmod);
 917   form[l + lm - 1] = spec;
 918   form[l + lm] = '\0';
 919 }
 920
 921
 922 static int str_format (lua_State *L) {
 923   int top = lua_gettop(L);
 924   int arg = 1;
 925   size_t sfl;
 926   const char *strfrmt = luaL_checklstring(L, arg, &sfl);
 927   const char *strfrmt_end = strfrmt+sfl;
 928   luaL_Buffer b;
 929   luaL_buffinit(L, &b);
 930   while (strfrmt < strfrmt_end) {
 931     if (*strfrmt != L_ESC)
 932       luaL_addchar(&b, *strfrmt++);
 933     else if (*++strfrmt == L_ESC)
 934       luaL_addchar(&b, *strfrmt++);  /* %% */
 935     else { /* format item */
 936       char form[MAX_FORMAT];  /* to store the format (`%...') */
 937       char *buff = luaL_prepbuffsize(&b, MAX_ITEM);  /* to put formatted item */
 938       int nb = 0;  /* number of bytes in added item */
 939       if (++arg > top)
 940         luaL_argerror(L, arg, "no value");
 941       strfrmt = scanformat(L, strfrmt, form);
 942       switch (*strfrmt++) {
 943         case 'c': {
 944           nb = str_sprintf(buff, form, luaL_checkint(L, arg));
 945           break;
 946         }
 947         case 'd': case 'i': {
 948           lua_Number n = luaL_checknumber(L, arg);
 949           LUA_INTFRM_T ni = (LUA_INTFRM_T)n;
 950           lua_Number diff = n - (lua_Number)ni;
 951           luaL_argcheck(L, -1 < diff && diff < 1, arg,
 952                         "not a number in proper range");
 953           addlenmod(form, LUA_INTFRMLEN);
 954           nb = str_sprintf(buff, form, ni);
 955           break;
 956         }
 957         case 'o': case 'u': case 'x': case 'X': {
 958           lua_Number n = luaL_checknumber(L, arg);
 959           unsigned LUA_INTFRM_T ni = (unsigned LUA_INTFRM_T)n;
 960           lua_Number diff = n - (lua_Number)ni;
 961           luaL_argcheck(L, -1 < diff && diff < 1, arg,
 962                         "not a non-negative number in proper range");
 963           addlenmod(form, LUA_INTFRMLEN);
 964           nb = str_sprintf(buff, form, ni);
 965           break;
 966         }
 967 #if defined(LUA_USE_FLOAT_FORMATS)
 968         case 'e': case 'E': case 'f':
 969 #if defined(LUA_USE_AFORMAT)
 970         case 'a': case 'A':
 971 #endif
 972         case 'g': case 'G': {
 973           addlenmod(form, LUA_FLTFRMLEN);
 974           nb = str_sprintf(buff, form, (LUA_FLTFRM_T)luaL_checknumber(L, arg));
 975           break;
 976         }
 977 #endif
 978         case 'q': {
 979           addquoted(L, &b, arg);
 980           break;
 981         }
 982         case 's': {
 983           size_t l;
 984           const char *s = luaL_tolstring(L, arg, &l);
 985           if (!strchr(form, '.') && l >= 100) {
 986             /* no precision and string is too long to be formatted;
 987                keep original string */
 988             luaL_addvalue(&b);
 989             break;
 990           }
 991           else {
 992             nb = str_sprintf(buff, form, s);
 993             lua_pop(L, 1);  /* remove result from 'luaL_tolstring' */
 994             break;
 995           }
 996         }
 997         default: {  /* also treat cases `pnLlh' */
 998           return luaL_error(L, "invalid option " LUA_QL("%%%c") " to "
 999                                LUA_QL("format"), *(strfrmt - 1));
1000         }
1001       }
1002       luaL_addsize(&b, nb);
1003     }
1004   }
1005   luaL_pushresult(&b);
1006   return 1;
1007 }
1008
1009 /* }====================================================== */
1010
1011
1012 static const luaL_Reg strlib[] = {
1013   {"byte", str_byte},
1014   {"char", str_char},
1015   {"dump", str_dump},
1016   {"find", str_find},
1017   {"format", str_format},
1018   {"gmatch", str_gmatch},
1019   {"gsub", str_gsub},
1020   {"len", str_len},
1021   {"lower", str_lower},
1022   {"match", str_match},
1023   {"rep", str_rep},
1024   {"reverse", str_reverse},
1025   {"sub", str_sub},
1026   {"upper", str_upper},
1027   {NULL, NULL}
1028 };
1029
1030
1031 static void createmetatable (lua_State *L) {
1032   lua_createtable(L, 0, 1);  /* table to be metatable for strings */
1033   lua_pushliteral(L, "");  /* dummy string */
1034   lua_pushvalue(L, -2);  /* copy table */
1035   lua_setmetatable(L, -2);  /* set table as metatable for strings */
1036   lua_pop(L, 1);  /* pop dummy string */
1037   lua_pushvalue(L, -2);  /* get string library */
1038   lua_setfield(L, -2, "__index");  /* metatable.__index = string */
1039   lua_pop(L, 1);  /* pop metatable */
1040 }
1041
1042
1043 /*
1044 ** Open string library
1045 */
1046 LUAMOD_API int luaopen_string (lua_State *L) {
1047   luaL_newlib(L, strlib);
1048   createmetatable(L);
1049   return 1;
1050 }
1051