/*

** $Id: llex.c,v 2.20.1.1 2007/12/27 13:02:25 roberto Exp $

** Lexical Analyzer

** See Copyright Notice in lua.h

*/

#include <ctype.h>

#include <locale.h>

#include <string.h>

#define llex_c

#define LUA_CORE

#include "lua.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 */

const char *const luaX_tokens [] = {

    "and", "break", "do", "else", "elseif",

    "end", "false", "for", "function", "if",

    "in", "local", "nil", "not", "or", "repeat",

    "return", "then", "true", "until", "while",

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

    "<number>", "<name>", "<string>", "<eof>",

    NULL

};

#define save_and_next(ls) (save(ls, ls->current), next(ls))

static void save (LexState *ls, int c) {

  Mbuffer *b = ls->buff;

  if (b->n + 1 > b->buffsize) {

    size_t newsize;

    if (b->buffsize >= MAX_SIZET/2)

      luaX_lexerror(ls, "lexical element too long", 0);

    newsize = b->buffsize * 2;

    luaZ_resizebuffer(ls->L, b, newsize);

  }

  b->buffer[b->n++] = 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 */

    lua_assert(strlen(luaX_tokens[i])+1 <= TOKEN_LEN);

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

  }

}

#define MAXSRC          80

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

  if (token < FIRST_RESERVED) {

    lua_assert(token == cast(unsigned char, token));

    return (iscntrl(token)) ? luaO_pushfstring(ls->L, "char(%d)", token) :

                              luaO_pushfstring(ls->L, "%c", token);

  }

  else

    return luaX_tokens[token-FIRST_RESERVED];

}

static const char *txtToken (LexState *ls, int token) {

  switch (token) {

    case TK_NAME:

    case TK_STRING:

    case TK_NUMBER:

      save(ls, '\0');

      return luaZ_buffer(ls->buff);

    default:

      return luaX_token2str(ls, token);

  }

}

void luaX_lexerror (LexState *ls, const char *msg, int token) {

  char buff[MAXSRC];

  luaO_chunkid(buff, getstr(ls->source), MAXSRC);

  msg = luaO_pushfstring(ls->L, "%s:%d: %s", buff, ls->linenumber, msg);

  if (token)

    luaO_pushfstring(ls->L, "%s near " LUA_QS, msg, txtToken(ls, token));

  luaD_throw(ls->L, LUA_ERRSYNTAX);

}

void luaX_syntaxerror (LexState *ls, const char *msg) {

  luaX_lexerror(ls, msg, ls->t.token);

}

TString *luaX_newstring (LexState *ls, const char *str, size_t l) {

  lua_State *L = ls->L;

  TString *ts = luaS_newlstr(L, str, l);

  TValue *o = luaH_setstr(L, ls->fs->h, ts);  /* entry for `str' */

  if (ttisnil(o))

    setbvalue(o, 1);  /* make sure `str' will not be collected */

  return ts;

}

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) {

  ls->decpoint = '.';

  ls->L = L;

  ls->lookahead.token = TK_EOS;  /* no look-ahead token */

  ls->z = z;

  ls->fs = NULL;

  ls->linenumber = 1;

  ls->lastline = 1;

  ls->source = source;

  luaZ_resizebuffer(ls->L, ls->buff, LUA_MINBUFFER);  /* initialize buffer */

  next(ls);  /* read first char */

}

/*

** =======================================================

** LEXICAL ANALYZER

** =======================================================

*/

static int check_next (LexState *ls, const char *set) {

  if (!strchr(set, ls->current))

    return 0;

  save_and_next(ls);

  return 1;

}

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;

}

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

  /* format error: try to update decimal point separator */

  struct lconv *cv = localeconv();

  char old = ls->decpoint;

  ls->decpoint = (cv ? cv->decimal_point[0] : '.');

  buffreplace(ls, old, ls->decpoint);  /* try updated decimal separator */

  if (!luaO_str2d(luaZ_buffer(ls->buff), &seminfo->r)) {

    /* format error with correct decimal point: no more options */

    buffreplace(ls, ls->decpoint, '.');  /* undo change (for error message) */

    luaX_lexerror(ls, "malformed number", TK_NUMBER);

  }

}

/* LUA_NUMBER */

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

  lua_assert(isdigit(ls->current));

  do {

    save_and_next(ls);

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

  if (check_next(ls, "Ee"))  /* `E'? */

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

  while (isalnum(ls->current) || ls->current == '_')

    save_and_next(ls);

  save(ls, '\0');

  buffreplace(ls, '.', ls->decpoint);  /* follow locale for decimal point */

  if (!luaO_str2d(luaZ_buffer(ls->buff), &seminfo->r))  /* format error? */

    trydecpoint(ls, seminfo); /* try to update decimal point separator */

}

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) {

  int cont = 0;

  (void)(cont);  /* avoid warnings when `cont' is not used */

  save_and_next(ls);  /* skip 2nd `[' */

  if (currIsNewline(ls))  /* string starts with a newline? */

    inclinenumber(ls);  /* skip it */

  for (;;) {

    switch (ls->current) {

      case EOZ:

        luaX_lexerror(ls, (seminfo) ? "unfinished long string" :

                                   "unfinished long comment", TK_EOS);

        break;  /* to avoid warnings */

#if defined(LUA_COMPAT_LSTR)

      case '[': {

        if (skip_sep(ls) == sep) {

          save_and_next(ls);  /* skip 2nd `[' */

          cont++;

#if LUA_COMPAT_LSTR == 1

          if (sep == 0)

            luaX_lexerror(ls, "nesting of [[...]] is deprecated", '[');

#endif

        }

        break;

      }

#endif

      case ']': {

        if (skip_sep(ls) == sep) {

          save_and_next(ls);  /* skip 2nd `]' */

#if defined(LUA_COMPAT_LSTR) && LUA_COMPAT_LSTR == 2

          cont--;

          if (sep == 0 && cont >= 0) break;

#endif

          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 read_string (LexState *ls, int del, SemInfo *seminfo) {

  save_and_next(ls);

  while (ls->current != del) {

    switch (ls->current) {

      case EOZ:

        luaX_lexerror(ls, "unfinished string", TK_EOS);

        continue;  /* to avoid warnings */

      case '\n':

      case '\r':

        luaX_lexerror(ls, "unfinished string", TK_STRING);

        continue;  /* to avoid warnings */

      case '\\': {

        int c;

        next(ls);  /* do not save the `\' */

        switch (ls->current) {

          case 'a': c = '\a'; break;

          case 'b': c = '\b'; break;

          case 'f': c = '\f'; break;

          case 'n': c = '\n'; break;

          case 'r': c = '\r'; break;

          case 't': c = '\t'; break;

          case 'v': c = '\v'; break;

          case '\n':  /* go through */

          case '\r': save(ls, '\n'); inclinenumber(ls); continue;

          case EOZ: continue;  /* will raise an error next loop */

          default: {

            if (!isdigit(ls->current))

              save_and_next(ls);  /* handles \\, \", \', and \? */

            else {  /* \xxx */

              int i = 0;

              c = 0;

              do {

                c = 10*c + (ls->current-'0');

                next(ls);

              } while (++i<3 && isdigit(ls->current));

              if (c > UCHAR_MAX)

                luaX_lexerror(ls, "escape sequence too large", TK_STRING);

              save(ls, c);

            }

            continue;

          }

        }

        save(ls, c);

        next(ls);

        continue;

      }

      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': {

        inclinenumber(ls);

        continue;

      }

      case '-': {

        next(ls);

        if (ls->current != '-') return '-';

        /* else is a comment */

        next(ls);

        if (ls->current == '[') {

          int sep = skip_sep(ls);

          luaZ_resetbuffer(ls->buff);  /* `skip_sep' may dirty the buffer */

          if (sep >= 0) {

            read_long_string(ls, NULL, sep);  /* long comment */

            luaZ_resetbuffer(ls->buff);

            continue;

          }

        }

        /* else short comment */

        while (!currIsNewline(ls) && ls->current != EOZ)

          next(ls);

        continue;

      }

      case '[': {

        int sep = skip_sep(ls);

        if (sep >= 0) {

          read_long_string(ls, seminfo, sep);

          return TK_STRING;

        }

        else if (sep == -1) return '[';

        else luaX_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 '"':

      case '\'': {

        read_string(ls, ls->current, seminfo);

        return TK_STRING;

      }

      case '.': {

        save_and_next(ls);

        if (check_next(ls, ".")) {

          if (check_next(ls, "."))

            return TK_DOTS;   /* ... */

          else return TK_CONCAT;   /* .. */

        }

        else if (!isdigit(ls->current)) return '.';

        else {

          read_numeral(ls, seminfo);

          return TK_NUMBER;

        }

      }

      case EOZ: {

        return TK_EOS;

      }

      default: {

        if (isspace(ls->current)) {

          lua_assert(!currIsNewline(ls));

          next(ls);

          continue;

        }

        else if (isdigit(ls->current)) {

          read_numeral(ls, seminfo);

          return TK_NUMBER;

        }

        else if (isalpha(ls->current) || ls->current == '_') {

          /* identifier or reserved word */

          TString *ts;

          do {

            save_and_next(ls);

          } while (isalnum(ls->current) || ls->current == '_');

          ts = luaX_newstring(ls, luaZ_buffer(ls->buff),

                                  luaZ_bufflen(ls->buff));

          if (ts->tsv.reserved > 0)  /* reserved word? */

            return ts->tsv.reserved - 1 + FIRST_RESERVED;

          else {

            seminfo->ts = ts;

            return TK_NAME;

          }

        }

        else {

          int c = ls->current;

          next(ls);

          return c;  /* single-char tokens (+ - / ...) */

        }

      }

    }

  }

}

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 */

}

void luaX_lookahead (LexState *ls) {

  lua_assert(ls->lookahead.token == TK_EOS);

  ls->lookahead.token = llex(ls, &ls->lookahead.seminfo);

}