cvs.zerfleddert.de Git - proxmark3-svn/blob - liblua/llex.c

   1 /*
   2 ** $Id: llex.c,v 2.63 2013/03/16 21:10:18 roberto Exp $
   3 ** Lexical Analyzer
   4 ** See Copyright Notice in lua.h
   5 */
   6
   7
   8 #include <locale.h>
   9 #include <string.h>
  10
  11 #define llex_c
  12 #define LUA_CORE
  13
  14 #include "lua.h"
  15
  16 #include "lctype.h"
  17 #include "ldo.h"
  18 #include "llex.h"
  19 #include "lobject.h"
  20 #include "lparser.h"
  21 #include "lstate.h"
  22 #include "lstring.h"
  23 #include "ltable.h"
  24 #include "lzio.h"
  25
  26
  27
  28 #define next(ls) (ls->current = zgetc(ls->z))
  29
  30
  31
  32 #define currIsNewline(ls)       (ls->current == '\n' || ls->current == '\r')
  33
  34
  35 /* ORDER RESERVED */
  36 static const char *const luaX_tokens [] = {
  37     "and", "break", "do", "else", "elseif",
  38     "end", "false", "for", "function", "goto", "if",
  39     "in", "local", "nil", "not", "or", "repeat",
  40     "return", "then", "true", "until", "while",
  41     "..", "...", "==", ">=", "<=", "~=", "::", "<eof>",
  42     "<number>", "<name>", "<string>"
  43 };
  44
  45
  46 #define save_and_next(ls) (save(ls, ls->current), next(ls))
  47
  48
  49 static l_noret lexerror (LexState *ls, const char *msg, int token);
  50
  51
  52 static void save (LexState *ls, int c) {
  53   Mbuffer *b = ls->buff;
  54   if (luaZ_bufflen(b) + 1 > luaZ_sizebuffer(b)) {
  55     size_t newsize;
  56     if (luaZ_sizebuffer(b) >= MAX_SIZET/2)
  57       lexerror(ls, "lexical element too long", 0);
  58     newsize = luaZ_sizebuffer(b) * 2;
  59     luaZ_resizebuffer(ls->L, b, newsize);
  60   }
  61   b->buffer[luaZ_bufflen(b)++] = cast(char, c);
  62 }
  63
  64
  65 void luaX_init (lua_State *L) {
  66   int i;
  67   for (i=0; i<NUM_RESERVED; i++) {
  68     TString *ts = luaS_new(L, luaX_tokens[i]);
  69     luaS_fix(ts);  /* reserved words are never collected */
  70     ts->tsv.extra = cast_byte(i+1);  /* reserved word */
  71   }
  72 }
  73
  74
  75 const char *luaX_token2str (LexState *ls, int token) {
  76   if (token < FIRST_RESERVED) {  /* single-byte symbols? */
  77     lua_assert(token == cast(unsigned char, token));
  78     return (lisprint(token)) ? luaO_pushfstring(ls->L, LUA_QL("%c"), token) :
  79                               luaO_pushfstring(ls->L, "char(%d)", token);
  80   }
  81   else {
  82     const char *s = luaX_tokens[token - FIRST_RESERVED];
  83     if (token < TK_EOS)  /* fixed format (symbols and reserved words)? */
  84       return luaO_pushfstring(ls->L, LUA_QS, s);
  85     else  /* names, strings, and numerals */
  86       return s;
  87   }
  88 }
  89
  90
  91 static const char *txtToken (LexState *ls, int token) {
  92   switch (token) {
  93     case TK_NAME:
  94     case TK_STRING:
  95     case TK_NUMBER:
  96       save(ls, '\0');
  97       return luaO_pushfstring(ls->L, LUA_QS, luaZ_buffer(ls->buff));
  98     default:
  99       return luaX_token2str(ls, token);
 100   }
 101 }
 102
 103
 104 static l_noret lexerror (LexState *ls, const char *msg, int token) {
 105   char buff[LUA_IDSIZE];
 106   luaO_chunkid(buff, getstr(ls->source), LUA_IDSIZE);
 107   msg = luaO_pushfstring(ls->L, "%s:%d: %s", buff, ls->linenumber, msg);
 108   if (token)
 109     luaO_pushfstring(ls->L, "%s near %s", msg, txtToken(ls, token));
 110   luaD_throw(ls->L, LUA_ERRSYNTAX);
 111 }
 112
 113
 114 l_noret luaX_syntaxerror (LexState *ls, const char *msg) {
 115   lexerror(ls, msg, ls->t.token);
 116 }
 117
 118
 119 /*
 120 ** creates a new string and anchors it in function's table so that
 121 ** it will not be collected until the end of the function's compilation
 122 ** (by that time it should be anchored in function's prototype)
 123 */
 124 TString *luaX_newstring (LexState *ls, const char *str, size_t l) {
 125   lua_State *L = ls->L;
 126   TValue *o;  /* entry for `str' */
 127   TString *ts = luaS_newlstr(L, str, l);  /* create new string */
 128   setsvalue2s(L, L->top++, ts);  /* temporarily anchor it in stack */
 129   o = luaH_set(L, ls->fs->h, L->top - 1);
 130   if (ttisnil(o)) {  /* not in use yet? (see 'addK') */
 131     /* boolean value does not need GC barrier;
 132        table has no metatable, so it does not need to invalidate cache */
 133     setbvalue(o, 1);  /* t[string] = true */
 134     luaC_checkGC(L);
 135   }
 136   L->top--;  /* remove string from stack */
 137   return ts;
 138 }
 139
 140
 141 /*
 142 ** increment line number and skips newline sequence (any of
 143 ** \n, \r, \n\r, or \r\n)
 144 */
 145 static void inclinenumber (LexState *ls) {
 146   int old = ls->current;
 147   lua_assert(currIsNewline(ls));
 148   next(ls);  /* skip `\n' or `\r' */
 149   if (currIsNewline(ls) && ls->current != old)
 150     next(ls);  /* skip `\n\r' or `\r\n' */
 151   if (++ls->linenumber >= MAX_INT)
 152     luaX_syntaxerror(ls, "chunk has too many lines");
 153 }
 154
 155
 156 void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source,
 157                     int firstchar) {
 158   ls->decpoint = '.';
 159   ls->L = L;
 160   ls->current = firstchar;
 161   ls->lookahead.token = TK_EOS;  /* no look-ahead token */
 162   ls->z = z;
 163   ls->fs = NULL;
 164   ls->linenumber = 1;
 165   ls->lastline = 1;
 166   ls->source = source;
 167   ls->envn = luaS_new(L, LUA_ENV);  /* create env name */
 168   luaS_fix(ls->envn);  /* never collect this name */
 169   luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER);  /* initialize buffer */
 170 }
 171
 172
 173
 174 /*
 175 ** =======================================================
 176 ** LEXICAL ANALYZER
 177 ** =======================================================
 178 */
 179
 180
 181
 182 static int check_next (LexState *ls, const char *set) {
 183   if (ls->current == '\0' || !strchr(set, ls->current))
 184     return 0;
 185   save_and_next(ls);
 186   return 1;
 187 }
 188
 189
 190 /*
 191 ** change all characters 'from' in buffer to 'to'
 192 */
 193 static void buffreplace (LexState *ls, char from, char to) {
 194   size_t n = luaZ_bufflen(ls->buff);
 195   char *p = luaZ_buffer(ls->buff);
 196   while (n--)
 197     if (p[n] == from) p[n] = to;
 198 }
 199
 200
 201 #if ANDROID
 202 #define getlocaldecpoint() '.'
 203 #elif !defined(getlocaledecpoint)
 204 #define getlocaledecpoint()     (localeconv()->decimal_point[0])
 205 #endif
 206
 207
 208 #define buff2d(b,e)     luaO_str2d(luaZ_buffer(b), luaZ_bufflen(b) - 1, e)
 209
 210 /*
 211 ** in case of format error, try to change decimal point separator to
 212 ** the one defined in the current locale and check again
 213 */
 214 static void trydecpoint (LexState *ls, SemInfo *seminfo) {
 215   char old = ls->decpoint;
 216   ls->decpoint = getlocaledecpoint();
 217   buffreplace(ls, old, ls->decpoint);  /* try new decimal separator */
 218   if (!buff2d(ls->buff, &seminfo->r)) {
 219     /* format error with correct decimal point: no more options */
 220     buffreplace(ls, ls->decpoint, '.');  /* undo change (for error message) */
 221     lexerror(ls, "malformed number", TK_NUMBER);
 222   }
 223 }
 224
 225
 226 /* LUA_NUMBER */
 227 /*
 228 ** this function is quite liberal in what it accepts, as 'luaO_str2d'
 229 ** will reject ill-formed numerals.
 230 */
 231 static void read_numeral (LexState *ls, SemInfo *seminfo) {
 232   const char *expo = "Ee";
 233   int first = ls->current;
 234   lua_assert(lisdigit(ls->current));
 235   save_and_next(ls);
 236   if (first == '0' && check_next(ls, "Xx"))  /* hexadecimal? */
 237     expo = "Pp";
 238   for (;;) {
 239     if (check_next(ls, expo))  /* exponent part? */
 240       check_next(ls, "+-");  /* optional exponent sign */
 241     if (lisxdigit(ls->current) || ls->current == '.')
 242       save_and_next(ls);
 243     else  break;
 244   }
 245   save(ls, '\0');
 246   buffreplace(ls, '.', ls->decpoint);  /* follow locale for decimal point */
 247   if (!buff2d(ls->buff, &seminfo->r))  /* format error? */
 248     trydecpoint(ls, seminfo); /* try to update decimal point separator */
 249 }
 250
 251
 252 /*
 253 ** skip a sequence '[=*[' or ']=*]' and return its number of '='s or
 254 ** -1 if sequence is malformed
 255 */
 256 static int skip_sep (LexState *ls) {
 257   int count = 0;
 258   int s = ls->current;
 259   lua_assert(s == '[' || s == ']');
 260   save_and_next(ls);
 261   while (ls->current == '=') {
 262     save_and_next(ls);
 263     count++;
 264   }
 265   return (ls->current == s) ? count : (-count) - 1;
 266 }
 267
 268
 269 static void read_long_string (LexState *ls, SemInfo *seminfo, int sep) {
 270   save_and_next(ls);  /* skip 2nd `[' */
 271   if (currIsNewline(ls))  /* string starts with a newline? */
 272     inclinenumber(ls);  /* skip it */
 273   for (;;) {
 274     switch (ls->current) {
 275       case EOZ:
 276         lexerror(ls, (seminfo) ? "unfinished long string" :
 277                                  "unfinished long comment", TK_EOS);
 278         break;  /* to avoid warnings */
 279       case ']': {
 280         if (skip_sep(ls) == sep) {
 281           save_and_next(ls);  /* skip 2nd `]' */
 282           goto endloop;
 283         }
 284         break;
 285       }
 286       case '\n': case '\r': {
 287         save(ls, '\n');
 288         inclinenumber(ls);
 289         if (!seminfo) luaZ_resetbuffer(ls->buff);  /* avoid wasting space */
 290         break;
 291       }
 292       default: {
 293         if (seminfo) save_and_next(ls);
 294         else next(ls);
 295       }
 296     }
 297   } endloop:
 298   if (seminfo)
 299     seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + (2 + sep),
 300                                      luaZ_bufflen(ls->buff) - 2*(2 + sep));
 301 }
 302
 303
 304 static void escerror (LexState *ls, int *c, int n, const char *msg) {
 305   int i;
 306   luaZ_resetbuffer(ls->buff);  /* prepare error message */
 307   save(ls, '\\');
 308   for (i = 0; i < n && c[i] != EOZ; i++)
 309     save(ls, c[i]);
 310   lexerror(ls, msg, TK_STRING);
 311 }
 312
 313
 314 static int readhexaesc (LexState *ls) {
 315   int c[3], i;  /* keep input for error message */
 316   int r = 0;  /* result accumulator */
 317   c[0] = 'x';  /* for error message */
 318   for (i = 1; i < 3; i++) {  /* read two hexadecimal digits */
 319     c[i] = next(ls);
 320     if (!lisxdigit(c[i]))
 321       escerror(ls, c, i + 1, "hexadecimal digit expected");
 322     r = (r << 4) + luaO_hexavalue(c[i]);
 323   }
 324   return r;
 325 }
 326
 327
 328 static int readdecesc (LexState *ls) {
 329   int c[3], i;
 330   int r = 0;  /* result accumulator */
 331   for (i = 0; i < 3 && lisdigit(ls->current); i++) {  /* read up to 3 digits */
 332     c[i] = ls->current;
 333     r = 10*r + c[i] - '0';
 334     next(ls);
 335   }
 336   if (r > UCHAR_MAX)
 337     escerror(ls, c, i, "decimal escape too large");
 338   return r;
 339 }
 340
 341
 342 static void read_string (LexState *ls, int del, SemInfo *seminfo) {
 343   save_and_next(ls);  /* keep delimiter (for error messages) */
 344   while (ls->current != del) {
 345     switch (ls->current) {
 346       case EOZ:
 347         lexerror(ls, "unfinished string", TK_EOS);
 348         break;  /* to avoid warnings */
 349       case '\n':
 350       case '\r':
 351         lexerror(ls, "unfinished string", TK_STRING);
 352         break;  /* to avoid warnings */
 353       case '\\': {  /* escape sequences */
 354         int c;  /* final character to be saved */
 355         next(ls);  /* do not save the `\' */
 356         switch (ls->current) {
 357           case 'a': c = '\a'; goto read_save;
 358           case 'b': c = '\b'; goto read_save;
 359           case 'f': c = '\f'; goto read_save;
 360           case 'n': c = '\n'; goto read_save;
 361           case 'r': c = '\r'; goto read_save;
 362           case 't': c = '\t'; goto read_save;
 363           case 'v': c = '\v'; goto read_save;
 364           case 'x': c = readhexaesc(ls); goto read_save;
 365           case '\n': case '\r':
 366             inclinenumber(ls); c = '\n'; goto only_save;
 367           case '\\': case '\"': case '\'':
 368             c = ls->current; goto read_save;
 369           case EOZ: goto no_save;  /* will raise an error next loop */
 370           case 'z': {  /* zap following span of spaces */
 371             next(ls);  /* skip the 'z' */
 372             while (lisspace(ls->current)) {
 373               if (currIsNewline(ls)) inclinenumber(ls);
 374               else next(ls);
 375             }
 376             goto no_save;
 377           }
 378           default: {
 379             if (!lisdigit(ls->current))
 380               escerror(ls, &ls->current, 1, "invalid escape sequence");
 381             /* digital escape \ddd */
 382             c = readdecesc(ls);
 383             goto only_save;
 384           }
 385         }
 386        read_save: next(ls);  /* read next character */
 387        only_save: save(ls, c);  /* save 'c' */
 388        no_save: break;
 389       }
 390       default:
 391         save_and_next(ls);
 392     }
 393   }
 394   save_and_next(ls);  /* skip delimiter */
 395   seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + 1,
 396                                    luaZ_bufflen(ls->buff) - 2);
 397 }
 398
 399
 400 static int llex (LexState *ls, SemInfo *seminfo) {
 401   luaZ_resetbuffer(ls->buff);
 402   for (;;) {
 403     switch (ls->current) {
 404       case '\n': case '\r': {  /* line breaks */
 405         inclinenumber(ls);
 406         break;
 407       }
 408       case ' ': case '\f': case '\t': case '\v': {  /* spaces */
 409         next(ls);
 410         break;
 411       }
 412       case '-': {  /* '-' or '--' (comment) */
 413         next(ls);
 414         if (ls->current != '-') return '-';
 415         /* else is a comment */
 416         next(ls);
 417         if (ls->current == '[') {  /* long comment? */
 418           int sep = skip_sep(ls);
 419           luaZ_resetbuffer(ls->buff);  /* `skip_sep' may dirty the buffer */
 420           if (sep >= 0) {
 421             read_long_string(ls, NULL, sep);  /* skip long comment */
 422             luaZ_resetbuffer(ls->buff);  /* previous call may dirty the buff. */
 423             break;
 424           }
 425         }
 426         /* else short comment */
 427         while (!currIsNewline(ls) && ls->current != EOZ)
 428           next(ls);  /* skip until end of line (or end of file) */
 429         break;
 430       }
 431       case '[': {  /* long string or simply '[' */
 432         int sep = skip_sep(ls);
 433         if (sep >= 0) {
 434           read_long_string(ls, seminfo, sep);
 435           return TK_STRING;
 436         }
 437         else if (sep == -1) return '[';
 438         else lexerror(ls, "invalid long string delimiter", TK_STRING);
 439       }
 440       case '=': {
 441         next(ls);
 442         if (ls->current != '=') return '=';
 443         else { next(ls); return TK_EQ; }
 444       }
 445       case '<': {
 446         next(ls);
 447         if (ls->current != '=') return '<';
 448         else { next(ls); return TK_LE; }
 449       }
 450       case '>': {
 451         next(ls);
 452         if (ls->current != '=') return '>';
 453         else { next(ls); return TK_GE; }
 454       }
 455       case '~': {
 456         next(ls);
 457         if (ls->current != '=') return '~';
 458         else { next(ls); return TK_NE; }
 459       }
 460       case ':': {
 461         next(ls);
 462         if (ls->current != ':') return ':';
 463         else { next(ls); return TK_DBCOLON; }
 464       }
 465       case '"': case '\'': {  /* short literal strings */
 466         read_string(ls, ls->current, seminfo);
 467         return TK_STRING;
 468       }
 469       case '.': {  /* '.', '..', '...', or number */
 470         save_and_next(ls);
 471         if (check_next(ls, ".")) {
 472           if (check_next(ls, "."))
 473             return TK_DOTS;   /* '...' */
 474           else return TK_CONCAT;   /* '..' */
 475         }
 476         else if (!lisdigit(ls->current)) return '.';
 477         /* else go through */
 478       }
 479       case '0': case '1': case '2': case '3': case '4':
 480       case '5': case '6': case '7': case '8': case '9': {
 481         read_numeral(ls, seminfo);
 482         return TK_NUMBER;
 483       }
 484       case EOZ: {
 485         return TK_EOS;
 486       }
 487       default: {
 488         if (lislalpha(ls->current)) {  /* identifier or reserved word? */
 489           TString *ts;
 490           do {
 491             save_and_next(ls);
 492           } while (lislalnum(ls->current));
 493           ts = luaX_newstring(ls, luaZ_buffer(ls->buff),
 494                                   luaZ_bufflen(ls->buff));
 495           seminfo->ts = ts;
 496           if (isreserved(ts))  /* reserved word? */
 497             return ts->tsv.extra - 1 + FIRST_RESERVED;
 498           else {
 499             return TK_NAME;
 500           }
 501         }
 502         else {  /* single-char tokens (+ - / ...) */
 503           int c = ls->current;
 504           next(ls);
 505           return c;
 506         }
 507       }
 508     }
 509   }
 510 }
 511
 512
 513 void luaX_next (LexState *ls) {
 514   ls->lastline = ls->linenumber;
 515   if (ls->lookahead.token != TK_EOS) {  /* is there a look-ahead token? */
 516     ls->t = ls->lookahead;  /* use this one */
 517     ls->lookahead.token = TK_EOS;  /* and discharge it */
 518   }
 519   else
 520     ls->t.token = llex(ls, &ls->t.seminfo);  /* read next token */
 521 }
 522
 523
 524 int luaX_lookahead (LexState *ls) {
 525   lua_assert(ls->lookahead.token == TK_EOS);
 526   ls->lookahead.token = llex(ls, &ls->lookahead.seminfo);
 527   return ls->lookahead.token;
 528 }
 529