lbaselib.c

Lua 语言解释器源码

/*
** $Id: lbaselib.c,v 1.130b 2003/04/03 13:35:34 roberto Exp $
** Basic library
** See Copyright Notice in lua.h
*/



#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#define lbaselib_c

#include "lua.h"

#include "lauxlib.h"
#include "lualib.h"




/*
** If your system does not support `stdout', you can just remove this function.
** If you need, you can define your own `print' function, following this
** model but changing `fputs' to put the strings at a proper place
** (a console window or a log file, for instance).
*/
static int luaB_print (lua_State *L) {
  int n = lua_gettop(L);  /* number of arguments */
  int i;
  lua_getglobal(L, "tostring");
  for (i=1; i<=n; i++) {
    const char *s;
    lua_pushvalue(L, -1);  /* function to be called */
    lua_pushvalue(L, i);   /* value to print */
    lua_call(L, 1, 1);
    s = lua_tostring(L, -1);  /* get result */
    if (s == NULL)
      return luaL_error(L, "`tostring' must return a string to `print'");
    if (i>1) fputs("\t", stdout);
    fputs(s, stdout);
    lua_pop(L, 1);  /* pop result */
  }
  fputs("\n", stdout);
  return 0;
}


static int luaB_tonumber (lua_State *L) {
  int base = luaL_optint(L, 2, 10);
  if (base == 10) {  /* standard conversion */
    luaL_checkany(L, 1);
    if (lua_isnumber(L, 1)) {
      lua_pushnumber(L, lua_tonumber(L, 1));
      return 1;
    }
  }
  else {
    const char *s1 = luaL_checkstring(L, 1);
    char *s2;
    unsigned long n;
    luaL_argcheck(L, 2 <= base && base <= 36, 2, "base out of range");
    n = strtoul(s1, &s2, base);
    if (s1 != s2) {  /* at least one valid digit? */
      while (isspace((unsigned char)(*s2))) s2++;  /* skip trailing spaces */
      if (*s2 == '\0') {  /* no invalid trailing characters? */
        lua_pushnumber(L, (lua_Number)n);
        return 1;
      }
    }
  }
  lua_pushnil(L);  /* else not a number */
  return 1;
}


static int luaB_error (lua_State *L) {
  int level = luaL_optint(L, 2, 1);
  luaL_checkany(L, 1);
  if (!lua_isstring(L, 1) || level == 0)
    lua_pushvalue(L, 1);  /* propagate error message without changes */
  else {  /* add extra information */
    luaL_where(L, level);
    lua_pushvalue(L, 1);
    lua_concat(L, 2);
  }
  return lua_error(L);
}


static int luaB_getmetatable (lua_State *L) {
  luaL_checkany(L, 1);
  if (!lua_getmetatable(L, 1)) {
    lua_pushnil(L);
    return 1;  /* no metatable */
  }
  luaL_getmetafield(L, 1, "__metatable");
  return 1;  /* returns either __metatable field (if present) or metatable */
}


static int luaB_setmetatable (lua_State *L) {
  int t = lua_type(L, 2);
  luaL_checktype(L, 1, LUA_TTABLE);
  luaL_argcheck(L, t == LUA_TNIL || t == LUA_TTABLE, 2,
                    "nil or table expected");
  if (luaL_getmetafield(L, 1, "__metatable"))
    luaL_error(L, "cannot change a protected metatable");
  lua_settop(L, 2);
  lua_setmetatable(L, 1);
  return 1;
}


static void getfunc (lua_State *L) {
  if (lua_isfunction(L, 1)) lua_pushvalue(L, 1);
  else {
    lua_Debug ar;
    int level = luaL_optint(L, 1, 1);
    luaL_argcheck(L, level >= 0, 1, "level must be non-negative");
    if (lua_getstack(L, level, &ar) == 0)
      luaL_argerror(L, 1, "invalid level");
    lua_getinfo(L, "f", &ar);
    if (lua_isnil(L, -1))
      luaL_error(L, "no function environment for tail call at level %d",
                    level);
  }
}


static int aux_getfenv (lua_State *L) {
  lua_getfenv(L, -1);
  lua_pushliteral(L, "__fenv");
  lua_rawget(L, -2);
  return !lua_isnil(L, -1);
}


static int luaB_getfenv (lua_State *L) {
  getfunc(L);
  if (!aux_getfenv(L))  /* __fenv not defined? */
    lua_pop(L, 1);  /* remove it, to return real environment */
  return 1;
}


static int luaB_setfenv (lua_State *L) {
  luaL_checktype(L, 2, LUA_TTABLE);
  getfunc(L);
  if (aux_getfenv(L))  /* __fenv defined? */
    luaL_error(L, "`setfenv' cannot change a protected environment");
  else
    lua_pop(L, 2);  /* remove __fenv and real environment table */
  lua_pushvalue(L, 2);
  if (lua_isnumber(L, 1) && lua_tonumber(L, 1) == 0)
    lua_replace(L, LUA_GLOBALSINDEX);
  else if (lua_setfenv(L, -2) == 0)
    luaL_error(L, "`setfenv' cannot change environment of given function");
  return 0;
}


static int luaB_rawequal (lua_State *L) {
  luaL_checkany(L, 1);
  luaL_checkany(L, 2);
  lua_pushboolean(L, lua_rawequal(L, 1, 2));
  return 1;
}


static int luaB_rawget (lua_State *L) {
  luaL_checktype(L, 1, LUA_TTABLE);
  luaL_checkany(L, 2);
  lua_rawget(L, 1);
  return 1;
}

static int luaB_rawset (lua_State *L) {
  luaL_checktype(L, 1, LUA_TTABLE);
  luaL_checkany(L, 2);
  luaL_checkany(L, 3);
  lua_rawset(L, 1);
  return 1;
}


static int luaB_gcinfo (lua_State *L) {
  lua_pushnumber(L, (lua_Number)lua_getgccount(L));
  lua_pushnumber(L, (lua_Number)lua_getgcthreshold(L));
  return 2;
}


static int luaB_collectgarbage (lua_State *L) {
  lua_setgcthreshold(L, luaL_optint(L, 1, 0));
  return 0;
}


static int luaB_type (lua_State *L) {
  luaL_checkany(L, 1);
  lua_pushstring(L, lua_typename(L, lua_type(L, 1)));
  return 1;
}


static int luaB_next (lua_State *L) {
  luaL_checktype(L, 1, LUA_TTABLE);
  lua_settop(L, 2);  /* create a 2nd argument if there isn't one */
  if (lua_next(L, 1))
    return 2;
  else {
    lua_pushnil(L);
    return 1;
  }
}


static int luaB_pairs (lua_State *L) {
  luaL_checktype(L, 1, LUA_TTABLE);
  lua_pushliteral(L, "next");
  lua_rawget(L, LUA_GLOBALSINDEX);  /* return generator, */
  lua_pushvalue(L, 1);  /* state, */
  lua_pushnil(L);  /* and initial value */
  return 3;
}


static int luaB_ipairs (lua_State *L) {
  lua_Number i = lua_tonumber(L, 2);
  luaL_checktype(L, 1, LUA_TTABLE);
  if (i == 0 && lua_isnone(L, 2)) {  /* `for' start? */
    lua_pushliteral(L, "ipairs");
    lua_rawget(L, LUA_GLOBALSINDEX);  /* return generator, */
    lua_pushvalue(L, 1);  /* state, */
    lua_pushnumber(L, 0);  /* and initial value */
    return 3;
  }
  else {  /* `for' step */
    i++;  /* next value */
    lua_pushnumber(L, i);
    lua_rawgeti(L, 1, (int)i);
    return (lua_isnil(L, -1)) ? 0 : 2;
  }
}


static int load_aux (lua_State *L, int status) {
  if (status == 0)  /* OK? */
    return 1;
  else {
    lua_pushnil(L);
    lua_insert(L, -2);  /* put before error message */
    return 2;  /* return nil plus error message */
  }
}


static int luaB_loadstring (lua_State *L) {
  size_t l;
  const char *s = luaL_checklstring(L, 1, &l);
  const char *chunkname = luaL_optstring(L, 2, s);
  return load_aux(L, luaL_loadbuffer(L, s, l, chunkname));
}


static int luaB_loadfile (lua_State *L) {
  const char *fname = luaL_optstring(L, 1, NULL);
  return load_aux(L, luaL_loadfile(L, fname));
}


static int luaB_dofile (lua_State *L) {
  const char *fname = luaL_optstring(L, 1, NULL);
  int n = lua_gettop(L);
  int status = luaL_loadfile(L, fname);
  if (status != 0) lua_error(L);
  lua_call(L, 0, LUA_MULTRET);
  return lua_gettop(L) - n;
}


static int luaB_assert (lua_State *L) {
  luaL_checkany(L, 1);
  if (!lua_toboolean(L, 1))
    return luaL_error(L, "%s", luaL_optstring(L, 2, "assertion failed!"));
  lua_settop(L, 1);
  return 1;
}


static int luaB_unpack (lua_State *L) {
  int n, i;
  luaL_checktype(L, 1, LUA_TTABLE);
  n = luaL_getn(L, 1);
  luaL_checkstack(L, n, "table too big to unpack");
  for (i=1; i<=n; i++)  /* push arg[1...n] */
    lua_rawgeti(L, 1, i);
  return n;
}


static int luaB_pcall (lua_State *L) {
  int status;
  luaL_checkany(L, 1);
  status = lua_pcall(L, lua_gettop(L) - 1, LUA_MULTRET, 0);
  lua_pushboolean(L, (status == 0));
  lua_insert(L, 1);
  return lua_gettop(L);  /* return status + all results */
}


static int luaB_xpcall (lua_State *L) {
  int status;
  luaL_checkany(L, 2);
  lua_settop(L, 2);
  lua_insert(L, 1);  /* put error function under function to be called */
  status = lua_pcall(L, 0, LUA_MULTRET, 1);
  lua_pushboolean(L, (status == 0));
  lua_replace(L, 1);
  return lua_gettop(L);  /* return status + all results */
}


static int luaB_tostring (lua_State *L) {
  char buff[128];
  luaL_checkany(L, 1);
  if (luaL_callmeta(L, 1, "__tostring"))  /* is there a metafield? */
    return 1;  /* use its value */
  switch (lua_type(L, 1)) {
    case LUA_TNUMBER:
      lua_pushstring(L, lua_tostring(L, 1));
      return 1;
    case LUA_TSTRING:
      lua_pushvalue(L, 1);
      return 1;