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/*

** $Id: llex.c,v 2.59 2011/11/30 12:43:51 roberto Exp $

** Lexical Analyzer

** See Copyright Notice in lua.h

*/

#include 

#include 

#define llex_c

#define LUA_CORE

#include "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",

    "..", "...", "==", ">=", "<=", "~=", "::", "",

    "", "", ""

};

#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

    TString *ts = luaS_new(L, luaX_tokens[i]);

    luaS_fix(ts);  /* reserved words are never collected */

    ts->tsv.reserved = cast_byte(i+1);  /* reserved word */

  }

}

const char *luaX_token2str (LexState *ls, int token) {

  if (token < FIRST_RESERVED) {

    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)

      return luaO_pushfstring(ls->L, LUA_QS, s);

    else

      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);

  }

  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)

    luaX_syntaxerror(ls, "chunk has too many lines");

}

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 */

static void read_numeral (LexState *ls, SemInfo *seminfo) {

  lua_assert(lisdigit(ls->current));

  do {

    save_and_next(ls);

    if (check_next(ls, "EePp"))  /* exponent part? */

      check_next(ls, "+-");  /* optional exponent sign */

  } while (lislalnum(ls->current) || ls->current == '.');

  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 hexa 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] - '0';

    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);

      }

      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 */

      }

      case '0': 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 (ts->tsv.reserved > 0)  /* reserved word? */

            return ts->tsv.reserved - 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;

}