FreeBSD/Linux Kernel Cross Reference
sys/contrib/openzfs/module/lua/llex.c

     /*
     ** $Id: llex.c,v 2.63.1.3 2015/02/09 17:56:34 roberto Exp $
     ** Lexical Analyzer
     ** See Copyright Notice in lua.h
     */
     
     #define llex_c
     #define LUA_CORE
     
    #include <sys/lua/lua.h>
    
    #include "lctype.h"
    #include "ldo.h"
    #include "llex.h"
    #include "lobject.h"
    #include "lparser.h"
    #include "lstate.h"
    #include "lstring.h"
    #include "ltable.h"
    #include "lzio.h"
    
    
    
    #define next(ls) (ls->current = zgetc(ls->z))
    
    
    
    #define currIsNewline(ls)       (ls->current == '\n' || ls->current == '\r')
    
    
    /* ORDER RESERVED */
    static const char *const luaX_tokens [] = {
        "and", "break", "do", "else", "elseif",
        "end", "false", "for", "function", "goto", "if",
        "in", "local", "nil", "not", "or", "repeat",
        "return", "then", "true", "until", "while",
        "..", "...", "==", ">=", "<=", "~=", "::", "<eof>",
        "<number>", "<name>", "<string>"
    };
    
    
    #define save_and_next(ls) (save(ls, ls->current), next(ls))
    
    
    static l_noret lexerror (LexState *ls, const char *msg, int token);
    
    
    static void save (LexState *ls, int c) {
      Mbuffer *b = ls->buff;
      if (luaZ_bufflen(b) + 1 > luaZ_sizebuffer(b)) {
        size_t newsize;
        if (luaZ_sizebuffer(b) >= MAX_SIZET/2)
          lexerror(ls, "lexical element too long", 0);
        newsize = luaZ_sizebuffer(b) * 2;
        luaZ_resizebuffer(ls->L, b, newsize);
      }
      b->buffer[luaZ_bufflen(b)++] = cast(char, c);
    }
    
    
    void luaX_init (lua_State *L) {
      int i;
      for (i=0; i<NUM_RESERVED; i++) {
        TString *ts = luaS_new(L, luaX_tokens[i]);
        luaS_fix(ts);  /* reserved words are never collected */
        ts->tsv.extra = cast_byte(i+1);  /* reserved word */
      }
    }
    
    
    const char *luaX_token2str (LexState *ls, int token) {
      if (token < FIRST_RESERVED) {  /* single-byte symbols? */
        lua_assert(token == cast(unsigned char, token));
        return (lisprint(token)) ? luaO_pushfstring(ls->L, LUA_QL("%c"), token) :
                                  luaO_pushfstring(ls->L, "char(%d)", token);
      }
      else {
        const char *s = luaX_tokens[token - FIRST_RESERVED];
        if (token < TK_EOS)  /* fixed format (symbols and reserved words)? */
          return luaO_pushfstring(ls->L, LUA_QS, s);
        else  /* names, strings, and numerals */
          return s;
      }
    }
    
    
    static const char *txtToken (LexState *ls, int token) {
      switch (token) {
        case TK_NAME:
        case TK_STRING:
        case TK_NUMBER:
          save(ls, '\0');
          return luaO_pushfstring(ls->L, LUA_QS, luaZ_buffer(ls->buff));
        default:
          return luaX_token2str(ls, token);
      }
    }
    
    
   static l_noret lexerror (LexState *ls, const char *msg, int token) {
     char buff[LUA_IDSIZE];
     luaO_chunkid(buff, getstr(ls->source), LUA_IDSIZE);
     msg = luaO_pushfstring(ls->L, "%s:%d: %s", buff, ls->linenumber, msg);
     if (token)
       luaO_pushfstring(ls->L, "%s near %s", msg, txtToken(ls, token));
     luaD_throw(ls->L, LUA_ERRSYNTAX);
   }
   
   
   l_noret luaX_syntaxerror (LexState *ls, const char *msg) {
     lexerror(ls, msg, ls->t.token);
   }
   
   
   /*
   ** creates a new string and anchors it in function's table so that
   ** it will not be collected until the end of the function's compilation
   ** (by that time it should be anchored in function's prototype)
   */
   TString *luaX_newstring (LexState *ls, const char *str, size_t l) {
     lua_State *L = ls->L;
     TValue *o;  /* entry for `str' */
     TString *ts = luaS_newlstr(L, str, l);  /* create new string */
     setsvalue2s(L, L->top++, ts);  /* temporarily anchor it in stack */
     o = luaH_set(L, ls->fs->h, L->top - 1);
     if (ttisnil(o)) {  /* not in use yet? (see 'addK') */
       /* boolean value does not need GC barrier;
          table has no metatable, so it does not need to invalidate cache */
       setbvalue(o, 1);  /* t[string] = true */
       luaC_checkGC(L);
     }
     else {  /* string already present */
       ts = rawtsvalue(keyfromval(o));  /* re-use value previously stored */
     }
     L->top--;  /* remove string from stack */
     return ts;
   }
   
   
   /*
   ** increment line number and skips newline sequence (any of
   ** \n, \r, \n\r, or \r\n)
   */
   static void inclinenumber (LexState *ls) {
     int old = ls->current;
     lua_assert(currIsNewline(ls));
     next(ls);  /* skip `\n' or `\r' */
     if (currIsNewline(ls) && ls->current != old)
       next(ls);  /* skip `\n\r' or `\r\n' */
     if (++ls->linenumber >= MAX_INT)
       lexerror(ls, "chunk has too many lines", 0);
   }
   
   
   void luaX_setinput (lua_State *L, LexState *ls, ZIO *z, TString *source,
                       int firstchar) {
     ls->decpoint = '.';
     ls->L = L;
     ls->current = firstchar;
     ls->lookahead.token = TK_EOS;  /* no look-ahead token */
     ls->z = z;
     ls->fs = NULL;
     ls->linenumber = 1;
     ls->lastline = 1;
     ls->source = source;
     ls->envn = luaS_new(L, LUA_ENV);  /* create env name */
     luaS_fix(ls->envn);  /* never collect this name */
     luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER);  /* initialize buffer */
   }
   
   
   
   /*
   ** =======================================================
   ** LEXICAL ANALYZER
   ** =======================================================
   */
   
   
   
   static int check_next (LexState *ls, const char *set) {
     if (ls->current == '\0' || !strchr(set, ls->current))
       return 0;
     save_and_next(ls);
     return 1;
   }
   
   
   /*
   ** change all characters 'from' in buffer to 'to'
   */
   static void buffreplace (LexState *ls, char from, char to) {
     size_t n = luaZ_bufflen(ls->buff);
     char *p = luaZ_buffer(ls->buff);
     while (n--)
       if (p[n] == from) p[n] = to;
   }
   
   
   #if !defined(getlocaledecpoint)
   #define getlocaledecpoint()     (localeconv()->decimal_point[0])
   #endif
   
   
   #define buff2d(b,e)     luaO_str2d(luaZ_buffer(b), luaZ_bufflen(b) - 1, e)
   
   /*
   ** in case of format error, try to change decimal point separator to
   ** the one defined in the current locale and check again
   */
   static void trydecpoint (LexState *ls, SemInfo *seminfo) {
     char old = ls->decpoint;
     ls->decpoint = getlocaledecpoint();
     buffreplace(ls, old, ls->decpoint);  /* try new decimal separator */
     if (!buff2d(ls->buff, &seminfo->r)) {
       /* format error with correct decimal point: no more options */
       buffreplace(ls, ls->decpoint, '.');  /* undo change (for error message) */
       lexerror(ls, "malformed number", TK_NUMBER);
     }
   }
   
   
   /* LUA_NUMBER */
   /*
   ** this function is quite liberal in what it accepts, as 'luaO_str2d'
   ** will reject ill-formed numerals.
   */
   static void read_numeral (LexState *ls, SemInfo *seminfo) {
     const char *expo = "Ee";
     int first = ls->current;
     lua_assert(lisdigit(ls->current));
     save_and_next(ls);
     if (first == '' && check_next(ls, "Xx"))  /* hexadecimal? */
       expo = "Pp";
     for (;;) {
       if (check_next(ls, expo))  /* exponent part? */
         (void) check_next(ls, "+-");  /* optional exponent sign */
       if (lisxdigit(ls->current) || ls->current == '.')
         save_and_next(ls);
       else  break;
     }
     save(ls, '\0');
     buffreplace(ls, '.', ls->decpoint);  /* follow locale for decimal point */
     if (!buff2d(ls->buff, &seminfo->r))  /* format error? */
       trydecpoint(ls, seminfo); /* try to update decimal point separator */
   }
   
   
   /*
   ** skip a sequence '[=*[' or ']=*]' and return its number of '='s or
   ** -1 if sequence is malformed
   */
   static int skip_sep (LexState *ls) {
     int count = 0;
     int s = ls->current;
     lua_assert(s == '[' || s == ']');
     save_and_next(ls);
     while (ls->current == '=') {
       save_and_next(ls);
       count++;
     }
     return (ls->current == s) ? count : (-count) - 1;
   }
   
   
   static void read_long_string (LexState *ls, SemInfo *seminfo, int sep) {
     save_and_next(ls);  /* skip 2nd `[' */
     if (currIsNewline(ls))  /* string starts with a newline? */
       inclinenumber(ls);  /* skip it */
     for (;;) {
       switch (ls->current) {
         case EOZ:
           lexerror(ls, (seminfo) ? "unfinished long string" :
                                    "unfinished long comment", TK_EOS);
           break;  /* to avoid warnings */
         case ']': {
           if (skip_sep(ls) == sep) {
             save_and_next(ls);  /* skip 2nd `]' */
             goto endloop;
           }
           break;
         }
         case '\n': case '\r': {
           save(ls, '\n');
           inclinenumber(ls);
           if (!seminfo) luaZ_resetbuffer(ls->buff);  /* avoid wasting space */
           break;
         }
         default: {
           if (seminfo) save_and_next(ls);
           else next(ls);
         }
       }
     } endloop:
     if (seminfo)
       seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + (2 + sep),
                                        luaZ_bufflen(ls->buff) - 2*(2 + sep));
   }
   
   
   static void escerror (LexState *ls, int *c, int n, const char *msg) {
     int i;
     luaZ_resetbuffer(ls->buff);  /* prepare error message */
     save(ls, '\\');
     for (i = 0; i < n && c[i] != EOZ; i++)
       save(ls, c[i]);
     lexerror(ls, msg, TK_STRING);
   }
   
   
   static int readhexaesc (LexState *ls) {
     int c[3], i;  /* keep input for error message */
     int r = 0;  /* result accumulator */
     c[0] = 'x';  /* for error message */
     for (i = 1; i < 3; i++) {  /* read two hexadecimal digits */
       c[i] = next(ls);
       if (!lisxdigit(c[i]))
         escerror(ls, c, i + 1, "hexadecimal digit expected");
       r = (r << 4) + luaO_hexavalue(c[i]);
     }
     return r;
   }
   
   
   static int readdecesc (LexState *ls) {
     int c[3], i;
     int r = 0;  /* result accumulator */
     for (i = 0; i < 3 && lisdigit(ls->current); i++) {  /* read up to 3 digits */
       c[i] = ls->current;
       r = 10*r + c[i] - '';
       next(ls);
     }
     if (r > UCHAR_MAX)
       escerror(ls, c, i, "decimal escape too large");
     return r;
   }
   
   
   static void read_string (LexState *ls, int del, SemInfo *seminfo) {
     save_and_next(ls);  /* keep delimiter (for error messages) */
     while (ls->current != del) {
       switch (ls->current) {
         case EOZ:
           lexerror(ls, "unfinished string", TK_EOS);
           break;  /* to avoid warnings */
         case '\n':
         case '\r':
           lexerror(ls, "unfinished string", TK_STRING);
           break;  /* to avoid warnings */
         case '\\': {  /* escape sequences */
           int c;  /* final character to be saved */
           next(ls);  /* do not save the `\' */
           switch (ls->current) {
             case 'a': c = '\a'; goto read_save;
             case 'b': c = '\b'; goto read_save;
             case 'f': c = '\f'; goto read_save;
             case 'n': c = '\n'; goto read_save;
             case 'r': c = '\r'; goto read_save;
             case 't': c = '\t'; goto read_save;
             case 'v': c = '\v'; goto read_save;
             case 'x': c = readhexaesc(ls); goto read_save;
             case '\n': case '\r':
               inclinenumber(ls); c = '\n'; goto only_save;
             case '\\': case '\"': case '\'':
               c = ls->current; goto read_save;
             case EOZ: goto no_save;  /* will raise an error next loop */
             case 'z': {  /* zap following span of spaces */
               next(ls);  /* skip the 'z' */
               while (lisspace(ls->current)) {
                 if (currIsNewline(ls)) inclinenumber(ls);
                 else next(ls);
               }
               goto no_save;
             }
             default: {
               if (!lisdigit(ls->current))
                 escerror(ls, &ls->current, 1, "invalid escape sequence");
               /* digital escape \ddd */
               c = readdecesc(ls);
               goto only_save;
             }
           }
          read_save: next(ls);  /* read next character */
          only_save: save(ls, c);  /* save 'c' */
          no_save: break;
         }
         default:
           save_and_next(ls);
       }
     }
     save_and_next(ls);  /* skip delimiter */
     seminfo->ts = luaX_newstring(ls, luaZ_buffer(ls->buff) + 1,
                                      luaZ_bufflen(ls->buff) - 2);
   }
   
   
   static int llex (LexState *ls, SemInfo *seminfo) {
     luaZ_resetbuffer(ls->buff);
     for (;;) {
       switch (ls->current) {
         case '\n': case '\r': {  /* line breaks */
           inclinenumber(ls);
           break;
         }
         case ' ': case '\f': case '\t': case '\v': {  /* spaces */
           next(ls);
           break;
         }
         case '-': {  /* '-' or '--' (comment) */
           next(ls);
           if (ls->current != '-') return '-';
           /* else is a comment */
           next(ls);
           if (ls->current == '[') {  /* long comment? */
             int sep = skip_sep(ls);
             luaZ_resetbuffer(ls->buff);  /* `skip_sep' may dirty the buffer */
             if (sep >= 0) {
               read_long_string(ls, NULL, sep);  /* skip long comment */
               luaZ_resetbuffer(ls->buff);  /* previous call may dirty the buff. */
               break;
             }
           }
           /* else short comment */
           while (!currIsNewline(ls) && ls->current != EOZ)
             next(ls);  /* skip until end of line (or end of file) */
           break;
         }
         case '[': {  /* long string or simply '[' */
           int sep = skip_sep(ls);
           if (sep >= 0) {
             read_long_string(ls, seminfo, sep);
             return TK_STRING;
           } else if (sep == -1) {
                   return '[';
           } else {
                   lexerror(ls, "invalid long string delimiter", TK_STRING);
                   break;
           }
         }
         case '=': {
           next(ls);
           if (ls->current != '=') return '=';
           else { next(ls); return TK_EQ; }
         }
         case '<': {
           next(ls);
           if (ls->current != '=') return '<';
           else { next(ls); return TK_LE; }
         }
         case '>': {
           next(ls);
           if (ls->current != '=') return '>';
           else { next(ls); return TK_GE; }
         }
         case '~': {
           next(ls);
           if (ls->current != '=') return '~';
           else { next(ls); return TK_NE; }
         }
         case ':': {
           next(ls);
           if (ls->current != ':') return ':';
           else { next(ls); return TK_DBCOLON; }
         }
         case '"': case '\'': {  /* short literal strings */
           read_string(ls, ls->current, seminfo);
           return TK_STRING;
         }
         case '.': {  /* '.', '..', '...', or number */
           save_and_next(ls);
           if (check_next(ls, ".")) {
             if (check_next(ls, "."))
               return TK_DOTS;   /* '...' */
             else return TK_CONCAT;   /* '..' */
           }
           else if (!lisdigit(ls->current)) return '.';
           /* else go through */
         }
           zfs_fallthrough;
         case '': case '1': case '2': case '3': case '4':
         case '5': case '6': case '7': case '8': case '9': {
           read_numeral(ls, seminfo);
           return TK_NUMBER;
         }
         case EOZ: {
           return TK_EOS;
         }
         default: {
           if (lislalpha(ls->current)) {  /* identifier or reserved word? */
             TString *ts;
             do {
               save_and_next(ls);
             } while (lislalnum(ls->current));
             ts = luaX_newstring(ls, luaZ_buffer(ls->buff),
                                     luaZ_bufflen(ls->buff));
             seminfo->ts = ts;
             if (isreserved(ts))  /* reserved word? */
               return ts->tsv.extra - 1 + FIRST_RESERVED;
             else {
               return TK_NAME;
             }
           }
           else {  /* single-char tokens (+ - / ...) */
             int c = ls->current;
             next(ls);
             return c;
           }
         }
       }
     }
   }
   
   
   void luaX_next (LexState *ls) {
     ls->lastline = ls->linenumber;
     if (ls->lookahead.token != TK_EOS) {  /* is there a look-ahead token? */
       ls->t = ls->lookahead;  /* use this one */
       ls->lookahead.token = TK_EOS;  /* and discharge it */
     }
     else
       ls->t.token = llex(ls, &ls->t.seminfo);  /* read next token */
   }
   
   
   int luaX_lookahead (LexState *ls) {
     lua_assert(ls->lookahead.token == TK_EOS);
     ls->lookahead.token = llex(ls, &ls->lookahead.seminfo);
     return ls->lookahead.token;
   }

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