text: /*
  ** $Id: lua.c,v 1.160.1.2 2007/12/28 15:32:23 roberto Exp $
  ** Lua stand-alone interpreter
  ** See Copyright Notice in lua.h
  */
  
  
  #include <signal.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #define lua_c
  
  #include "lua.h"
  
  #include "lauxlib.h"
  #include "lualib.h"
  
  
  
  static lua_State *globalL = NULL;
  
  static const char *progname = LUA_PROGNAME;
  
  
  
  static void lstop (lua_State *L, lua_Debug *ar) {
    (void)ar;  /* unused arg. */
    lua_sethook(L, NULL, 0, 0);
    luaL_error(L, "interrupted!");
  }
  
  
  static void laction (int i) {
    signal(i, SIG_DFL); /* if another SIGINT happens before lstop,
                                terminate process (default action) */
    lua_sethook(globalL, lstop, LUA_MASKCALL | LUA_MASKRET | LUA_MASKCOUNT, 1);
  }
  
  
  static void print_usage (void) {
    fprintf(stderr,
    "usage: %s [options] [script [args]].\n"
    "Available options are:\n"
    "  -e stat  execute string " LUA_QL("stat") "\n"
    "  -l name  require library " LUA_QL("name") "\n"
    "  -i       enter interactive mode after executing " LUA_QL("script") "\n"
    "  -v       show version information\n"
    "  --       stop handling options\n"
    "  -        execute stdin and stop handling options\n"
    ,
    progname);
    fflush(stderr);
  }
  
  
  static void l_message (const char *pname, const char *msg) {
    if (pname) fprintf(stderr, "%s: ", pname);
    fprintf(stderr, "%s\n", msg);
    fflush(stderr);
  }
  
  
  static int report (lua_State *L, int status) {
    if (status && !lua_isnil(L, -1)) {
      const char *msg = lua_tostring(L, -1);
      if (msg == NULL) msg = "(error object is not a string)";
      l_message(progname, msg);
      lua_pop(L, 1);
    }
    return status;
  }
  
  
  static int traceback (lua_State *L) {
    if (!lua_isstring(L, 1))  /* 'message' not a string? */
      return 1;  /* keep it intact */
    lua_getfield(L, LUA_GLOBALSINDEX, "debug");
    if (!lua_istable(L, -1)) {
      lua_pop(L, 1);
      return 1;
    }
    lua_getfield(L, -1, "traceback");
    if (!lua_isfunction(L, -1)) {
      lua_pop(L, 2);
      return 1;
    }
    lua_pushvalue(L, 1);  /* pass error message */
    lua_pushinteger(L, 2);  /* skip this function and traceback */
    lua_call(L, 2, 1);  /* call debug.traceback */
    return 1;
  }
  
  
  static int docall (lua_State *L, int narg, int clear) {
    int status;
    int base = lua_gettop(L) - narg;  /* function index */
    lua_pushcfunction(L, traceback);  /* push traceback function */
    lua_insert(L, base);  /* put it under chunk and args */
    signal(SIGINT, laction);
    status = lua_pcall(L, narg, (clear ? 0 : LUA_MULTRET), base);
    signal(SIGINT, SIG_DFL);
    lua_remove(L, base);  /* remove traceback function */
    /* force a complete garbage collection in case of errors */
    if (status != 0) lua_gc(L, LUA_GCCOLLECT, 0);
    return status;
  }
  
  
  static void print_version (void) {
    l_message(NULL, LUA_RELEASE "  " LUA_COPYRIGHT);
  }
  
  
  static int getargs (lua_State *L, char **argv, int n) {
    int narg;
    int i;
    int argc = 0;
    while (argv[argc]) argc++;  /* count total number of arguments */
    narg = argc - (n + 1);  /* number of arguments to the script */
    luaL_checkstack(L, narg + 3, "too many arguments to script");
    for (i=n+1; i < argc; i++)
      lua_pushstring(L, argv[i]);
    lua_createtable(L, narg, n + 1);
    for (i=0; i < argc; i++) {
      lua_pushstring(L, argv[i]);
      lua_rawseti(L, -2, i - n);
    }
    return narg;
  }
  
  
  static int dofile (lua_State *L, const char *name) {
    int status = luaL_loadfile(L, name) || docall(L, 0, 1);
    return report(L, status);
  }
  
  
  static int dostring (lua_State *L, const char *s, const char *name) {
    int status = luaL_loadbuffer(L, s, strlen(s), name) || docall(L, 0, 1);
    return report(L, status);
  }
  
  
  static int dolibrary (lua_State *L, const char *name) {
    lua_getglobal(L, "require");
    lua_pushstring(L, name);
    return report(L, docall(L, 1, 1));
  }
  
  
  static const char *get_prompt (lua_State *L, int firstline) {
    const char *p;
    lua_getfield(L, LUA_GLOBALSINDEX, firstline ? "_PROMPT" : "_PROMPT2");
    p = lua_tostring(L, -1);
    if (p == NULL) p = (firstline ? LUA_PROMPT : LUA_PROMPT2);
    lua_pop(L, 1);  /* remove global */
    return p;
  }
  
  
  static int incomplete (lua_State *L, int status) {
    if (status == LUA_ERRSYNTAX) {
      size_t lmsg;
      const char *msg = lua_tolstring(L, -1, &lmsg);
      const char *tp = msg + lmsg - (sizeof(LUA_QL("<eof>")) - 1);
      if (strstr(msg, LUA_QL("<eof>")) == tp) {
        lua_pop(L, 1);
        return 1;
      }
    }
    return 0;  /* else... */
  }
  
  
  static int pushline (lua_State *L, int firstline) {
    char buffer[LUA_MAXINPUT];
    char *b = buffer;
    size_t l;
    const char *prmt = get_prompt(L, firstline);
    if (lua_readline(L, b, prmt) == 0)
      return 0;  /* no input */
    l = strlen(b);
    if (l > 0 && b[l-1] == '\n')  /* line ends with newline? */
      b[l-1] = '\0';  /* remove it */
    if (firstline && b[0] == '=')  /* first line starts with `=' ? */
      lua_pushfstring(L, "return %s", b+1);  /* change it to `return' */
    else
      lua_pushstring(L, b);
    lua_freeline(L, b);
    return 1;
  }
  
  
  static int loadline (lua_State *L) {
    int status;
    lua_settop(L, 0);
    if (!pushline(L, 1))
      return -1;  /* no input */
    for (;;) {  /* repeat until gets a complete line */
      status = luaL_loadbuffer(L, lua_tostring(L, 1), lua_strlen(L, 1), "=stdin");
      if (!incomplete(L, status)) break;  /* cannot try to add lines? */
      if (!pushline(L, 0))  /* no more input? */
        return -1;
      lua_pushliteral(L, "\n");  /* add a new line... */
      lua_insert(L, -2);  /* ...between the two lines */
      lua_concat(L, 3);  /* join them */
    }
    lua_saveline(L, 1);
    lua_remove(L, 1);  /* remove line */
    return status;
  }
  
  
  static void dotty (lua_State *L) {
    int status;
    const char *oldprogname = progname;
    progname = NULL;
    while ((status = loadline(L)) != -1) {
      if (status == 0) status = docall(L, 0, 0);
      report(L, status);
      if (status == 0 && lua_gettop(L) > 0) {  /* any result to print? */
        lua_getglobal(L, "print");
        lua_insert(L, 1);
        if (lua_pcall(L, lua_gettop(L)-1, 0, 0) != 0)
          l_message(progname, lua_pushfstring(L,
                                 "error calling " LUA_QL("print") " (%s)",
                                 lua_tostring(L, -1)));
      }
    }
    lua_settop(L, 0);  /* clear stack */
    fputs("\n", stdout);
    fflush(stdout);
    progname = oldprogname;
  }
  
  
  static int handle_script (lua_State *L, char **argv, int n) {
    int status;
    const char *fname;
    int narg = getargs(L, argv, n);  /* collect arguments */
    lua_setglobal(L, "arg");
    fname = argv[n];
    if (strcmp(fname, "-") == 0 && strcmp(argv[n-1], "--") != 0) 
      fname = NULL;  /* stdin */
    status = luaL_loadfile(L, fname);
    lua_insert(L, -(narg+1));
    if (status == 0)
      status = docall(L, narg, 0);
    else
      lua_pop(L, narg);      
    return report(L, status);
  }
  
  
  /* check that argument has no extra characters at the end */
  #define notail(x)	{if ((x)[2] != '\0') return -1;}
  
  
  static int collectargs (char **argv, int *pi, int *pv, int *pe) {
    int i;
    for (i = 1; argv[i] != NULL; i++) {
      if (argv[i][0] != '-')  /* not an option? */
          return i;
      switch (argv[i][1]) {  /* option */
        case '-':
          notail(argv[i]);
          return (argv[i+1] != NULL ? i+1 : 0);
        case '\0':
          return i;
        case 'i':
          notail(argv[i]);
          *pi = 1;  /* go through */
        case 'v':
          notail(argv[i]);
          *pv = 1;
          break;
        case 'e':
          *pe = 1;  /* go through */
        case 'l':
          if (argv[i][2] == '\0') {
            i++;
            if (argv[i] == NULL) return -1;
          }
          break;
        default: return -1;  /* invalid option */
      }
    }
    return 0;
  }
  
  
  static int runargs (lua_State *L, char **argv, int n) {
    int i;
    for (i = 1; i < n; i++) {
      if (argv[i] == NULL) continue;
      lua_assert(argv[i][0] == '-');
      switch (argv[i][1]) {  /* option */
        case 'e': {
          const char *chunk = argv[i] + 2;
          if (*chunk == '\0') chunk = argv[++i];
          lua_assert(chunk != NULL);
          if (dostring(L, chunk, "=(command line)") != 0)
            return 1;
          break;
        }
        case 'l': {
          const char *filename = argv[i] + 2;
          if (*filename == '\0') filename = argv[++i];
          lua_assert(filename != NULL);
          if (dolibrary(L, filename))
            return 1;  /* stop if file fails */
          break;
        }
        default: break;
      }
    }
    return 0;
  }
  
  
  static int handle_luainit (lua_State *L) {
    const char *init = getenv(LUA_INIT);
    if (init == NULL) return 0;  /* status OK */
    else if (init[0] == '@')
      return dofile(L, init+1);
    else
      return dostring(L, init, "=" LUA_INIT);
  }
  
  
  struct Smain {
    int argc;
    char **argv;
    int status;
  };
  
  
  static int pmain (lua_State *L) {
    struct Smain *s = (struct Smain *)lua_touserdata(L, 1);
    char **argv = s->argv;
    int script;
    int has_i = 0, has_v = 0, has_e = 0;
    globalL = L;
    if (argv[0] && argv[0][0]) progname = argv[0];
    lua_gc(L, LUA_GCSTOP, 0);  /* stop collector during initialization */
    luaL_openlibs(L);  /* open libraries */
    lua_gc(L, LUA_GCRESTART, 0);
    s->status = handle_luainit(L);
    if (s->status != 0) return 0;
    script = collectargs(argv, &has_i, &has_v, &has_e);
    if (script < 0) {  /* invalid args? */
      print_usage();
      s->status = 1;
      return 0;
    }
    if (has_v) print_version();
    s->status = runargs(L, argv, (script > 0) ? script : s->argc);
    if (s->status != 0) return 0;
    if (script)
      s->status = handle_script(L, argv, script);
    if (s->status != 0) return 0;
    if (has_i)
      dotty(L);
    else if (script == 0 && !has_e && !has_v) {
      if (lua_stdin_is_tty()) {
        print_version();
        dotty(L);
      }
      else dofile(L, NULL);  /* executes stdin as a file */
    }
    return 0;
  }
  
  
  #ifdef __ANDROID__
      int dummy_main (int argc, char **argv) {
  #else
      int main (int argc, char **argv) {
  #endif
    int status;
    struct Smain s;
    lua_State *L = lua_open();  /* create state */
    if (L == NULL) {
      l_message(argv[0], "cannot create state: not enough memory");
      return EXIT_FAILURE;
    }
    s.argc = argc;
    s.argv = argv;
    status = lua_cpcall(L, &pmain, &s);
    report(L, status);
    lua_close(L);
    #ifdef __ANDROID__
      return EXIT_SUCCESS;
    #else
      return (status || s.status) ? EXIT_FAILURE : EXIT_SUCCESS;
    #endif
  }
  
  