lstrlib.c

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