text: /*
  ** $Id: lbaselib.c $
  ** Basic library
  ** See Copyright Notice in lua.h
  */
  
  #define lbaselib_c
  #define LUA_LIB
  
  #include "lprefix.h"
  
  
  #include <ctype.h>
  #include <stdio.h>
  #include <stdlib.h>
  #include <string.h>
  
  #include "lua.h"
  
  #include "lauxlib.h"
  #include "lualib.h"
  
  
  static int luaB_print (lua_State *L) {
    int n = lua_gettop(L);  /* number of arguments */
    int i;
    for (i = 1; i <= n; i++) {  /* for each argument */
      size_t l;
      const char *s = luaL_tolstring(L, i, &l);  /* convert it to string */
      if (i > 1)  /* not the first element? */
        lua_writestring("\t", 1);  /* add a tab before it */
      lua_writestring(s, l);  /* print it */
      lua_pop(L, 1);  /* pop result */
    }
    lua_writeline();
    return 0;
  }
  
  
  /*
  ** Creates a warning with all given arguments.
  ** Check first for errors; otherwise an error may interrupt
  ** the composition of a warning, leaving it unfinished.
  */
  static int luaB_warn (lua_State *L) {
    int n = lua_gettop(L);  /* number of arguments */
    int i;
    luaL_checkstring(L, 1);  /* at least one argument */
    for (i = 2; i <= n; i++)
      luaL_checkstring(L, i);  /* make sure all arguments are strings */
    for (i = 1; i < n; i++)  /* compose warning */
      lua_warning(L, lua_tostring(L, i), 1);
    lua_warning(L, lua_tostring(L, n), 0);  /* close warning */
    return 0;
  }
  
  
  #define SPACECHARS	" \f\n\r\t\v"
  
  static const char *b_str2int (const char *s, int base, lua_Integer *pn) {
    lua_Unsigned n = 0;
    int neg = 0;
    s += strspn(s, SPACECHARS);  /* skip initial spaces */
    if (*s == '-') { s++; neg = 1; }  /* handle sign */
    else if (*s == '+') s++;
    if (!isalnum((unsigned char)*s))  /* no digit? */
      return NULL;
    do {
      int digit = (isdigit((unsigned char)*s)) ? *s - '0'
                     : (toupper((unsigned char)*s) - 'A') + 10;
      if (digit >= base) return NULL;  /* invalid numeral */
      n = n * base + digit;
      s++;
    } while (isalnum((unsigned char)*s));
    s += strspn(s, SPACECHARS);  /* skip trailing spaces */
    *pn = (lua_Integer)((neg) ? (0u - n) : n);
    return s;
  }
  
  
  static int luaB_tonumber (lua_State *L) {
    if (lua_isnoneornil(L, 2)) {  /* standard conversion? */
      if (lua_type(L, 1) == LUA_TNUMBER) {  /* already a number? */
        lua_settop(L, 1);  /* yes; return it */
        return 1;
      }
      else {
        size_t l;
        const char *s = lua_tolstring(L, 1, &l);
        if (s != NULL && lua_stringtonumber(L, s) == l + 1)
          return 1;  /* successful conversion to number */
        /* else not a number */
        luaL_checkany(L, 1);  /* (but there must be some parameter) */
      }
    }
    else {
      size_t l;
      const char *s;
      lua_Integer n = 0;  /* to avoid warnings */
      lua_Integer base = luaL_checkinteger(L, 2);
      luaL_checktype(L, 1, LUA_TSTRING);  /* no numbers as strings */
      s = lua_tolstring(L, 1, &l);
      luaL_argcheck(L, 2 <= base && base <= 36, 2, "base out of range");
      if (b_str2int(s, (int)base, &n) == s + l) {
        lua_pushinteger(L, n);
        return 1;
      }  /* else not a number */
    }  /* else not a number */
    luaL_pushfail(L);  /* not a number */
    return 1;
  }
  
  
  static int luaB_error (lua_State *L) {
    int level = (int)luaL_optinteger(L, 2, 1);
    lua_settop(L, 1);
    if (lua_type(L, 1) == LUA_TSTRING && level > 0) {
      luaL_where(L, level);   /* add extra information */
      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_argexpected(L, t == LUA_TNIL || t == LUA_TTABLE, 2, "nil or table");
    if (l_unlikely(luaL_getmetafield(L, 1, "__metatable") != LUA_TNIL))
      return luaL_error(L, "cannot change a protected metatable");
    lua_settop(L, 2);
    lua_setmetatable(L, 1);
    return 1;
  }
  
  
  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_rawlen (lua_State *L) {
    int t = lua_type(L, 1);
    luaL_argexpected(L, t == LUA_TTABLE || t == LUA_TSTRING, 1,
                        "table or string");
    lua_pushinteger(L, lua_rawlen(L, 1));
    return 1;
  }
  
  
  static int luaB_rawget (lua_State *L) {
    luaL_checktype(L, 1, LUA_TTABLE);
    luaL_checkany(L, 2);
    lua_settop(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_settop(L, 3);
    lua_rawset(L, 1);
    return 1;
  }
  
  
  static int pushmode (lua_State *L, int oldmode) {
    lua_pushstring(L, (oldmode == LUA_GCINC) ? "incremental"
                                             : "generational");
    return 1;
  }
  
  
  static int luaB_collectgarbage (lua_State *L) {
    static const char *const opts[] = {"stop", "restart", "collect",
      "count", "step", "setpause", "setstepmul",
      "isrunning", "generational", "incremental", NULL};
    static const int optsnum[] = {LUA_GCSTOP, LUA_GCRESTART, LUA_GCCOLLECT,
      LUA_GCCOUNT, LUA_GCSTEP, LUA_GCSETPAUSE, LUA_GCSETSTEPMUL,
      LUA_GCISRUNNING, LUA_GCGEN, LUA_GCINC};
    int o = optsnum[luaL_checkoption(L, 1, "collect", opts)];
    switch (o) {
      case LUA_GCCOUNT: {
        int k = lua_gc(L, o);
        int b = lua_gc(L, LUA_GCCOUNTB);
        lua_pushnumber(L, (lua_Number)k + ((lua_Number)b/1024));
        return 1;
      }
      case LUA_GCSTEP: {
        int step = (int)luaL_optinteger(L, 2, 0);
        int res = lua_gc(L, o, step);
        lua_pushboolean(L, res);
        return 1;
      }
      case LUA_GCSETPAUSE:
      case LUA_GCSETSTEPMUL: {
        int p = (int)luaL_optinteger(L, 2, 0);
        int previous = lua_gc(L, o, p);
        lua_pushinteger(L, previous);
        return 1;
      }
      case LUA_GCISRUNNING: {
        int res = lua_gc(L, o);
        lua_pushboolean(L, res);
        return 1;
      }
      case LUA_GCGEN: {
        int minormul = (int)luaL_optinteger(L, 2, 0);
        int majormul = (int)luaL_optinteger(L, 3, 0);
        return pushmode(L, lua_gc(L, o, minormul, majormul));
      }
      case LUA_GCINC: {
        int pause = (int)luaL_optinteger(L, 2, 0);
        int stepmul = (int)luaL_optinteger(L, 3, 0);
        int stepsize = (int)luaL_optinteger(L, 4, 0);
        return pushmode(L, lua_gc(L, o, pause, stepmul, stepsize));
      }
      default: {
        int res = lua_gc(L, o);
        lua_pushinteger(L, res);
        return 1;
      }
    }
  }
  
  
  static int luaB_type (lua_State *L) {
    int t = lua_type(L, 1);
    luaL_argcheck(L, t != LUA_TNONE, 1, "value expected");
    lua_pushstring(L, lua_typename(L, t));
    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_checkany(L, 1);
    if (luaL_getmetafield(L, 1, "__pairs") == LUA_TNIL) {  /* no metamethod? */
      lua_pushcfunction(L, luaB_next);  /* will return generator, */
      lua_pushvalue(L, 1);  /* state, */
      lua_pushnil(L);  /* and initial value */
    }
    else {
      lua_pushvalue(L, 1);  /* argument 'self' to metamethod */
      lua_call(L, 1, 3);  /* get 3 values from metamethod */
    }
    return 3;
  }
  
  
  /*
  ** Traversal function for 'ipairs'
  */
  static int ipairsaux (lua_State *L) {
    lua_Integer i = luaL_checkinteger(L, 2) + 1;
    lua_pushinteger(L, i);
    return (lua_geti(L, 1, i) == LUA_TNIL) ? 1 : 2;
  }
  
  
  /*
  ** 'ipairs' function. Returns 'ipairsaux', given "table", 0.
  ** (The given "table" may not be a table.)
  */
  static int luaB_ipairs (lua_State *L) {
    luaL_checkany(L, 1);
    lua_pushcfunction(L, ipairsaux);  /* iteration function */
    lua_pushvalue(L, 1);  /* state */
    lua_pushinteger(L, 0);  /* initial value */
    return 3;
  }
  
  
  static int load_aux (lua_State *L, int status, int envidx) {
    if (l_likely(status == LUA_OK)) {
      if (envidx != 0) {  /* 'env' parameter? */
        lua_pushvalue(L, envidx);  /* environment for loaded function */
        if (!lua_setupvalue(L, -2, 1))  /* set it as 1st upvalue */
          lua_pop(L, 1);  /* remove 'env' if not used by previous call */
      }
      return 1;
    }
    else {  /* error (message is on top of the stack) */
      luaL_pushfail(L);
      lua_insert(L, -2);  /* put before error message */
      return 2;  /* return fail plus error message */
    }
  }
  
  
  static int luaB_loadfile (lua_State *L) {
    const char *fname = luaL_optstring(L, 1, NULL);
    const char *mode = luaL_optstring(L, 2, NULL);
    int env = (!lua_isnone(L, 3) ? 3 : 0);  /* 'env' index or 0 if no 'env' */
    int status = luaL_loadfilex(L, fname, mode);
    return load_aux(L, status, env);
  }
  
  
  /*
  ** {======================================================
  ** Generic Read function
  ** =======================================================
  */
  
  
  /*
  ** reserved slot, above all arguments, to hold a copy of the returned
  ** string to avoid it being collected while parsed. 'load' has four
  ** optional arguments (chunk, source name, mode, and environment).
  */
  #define RESERVEDSLOT	5
  
  
  /*
  ** Reader for generic 'load' function: 'lua_load' uses the
  ** stack for internal stuff, so the reader cannot change the
  ** stack top. Instead, it keeps its resulting string in a
  ** reserved slot inside the stack.
  */
  static const char *generic_reader (lua_State *L, void *ud, size_t *size) {
    (void)(ud);  /* not used */
    luaL_checkstack(L, 2, "too many nested functions");
    lua_pushvalue(L, 1);  /* get function */
    lua_call(L, 0, 1);  /* call it */
    if (lua_isnil(L, -1)) {
      lua_pop(L, 1);  /* pop result */
      *size = 0;
      return NULL;
    }
    else if (l_unlikely(!lua_isstring(L, -1)))
      luaL_error(L, "reader function must return a string");
    lua_replace(L, RESERVEDSLOT);  /* save string in reserved slot */
    return lua_tolstring(L, RESERVEDSLOT, size);
  }
  
  
  static int luaB_load (lua_State *L) {
    int status;
    size_t l;
    const char *s = lua_tolstring(L, 1, &l);
    const char *mode = luaL_optstring(L, 3, "bt");
    int env = (!lua_isnone(L, 4) ? 4 : 0);  /* 'env' index or 0 if no 'env' */
    if (s != NULL) {  /* loading a string? */
      const char *chunkname = luaL_optstring(L, 2, s);
      status = luaL_loadbufferx(L, s, l, chunkname, mode);
    }
    else {  /* loading from a reader function */
      const char *chunkname = luaL_optstring(L, 2, "=(load)");
      luaL_checktype(L, 1, LUA_TFUNCTION);
      lua_settop(L, RESERVEDSLOT);  /* create reserved slot */
      status = lua_load(L, generic_reader, NULL, chunkname, mode);
    }
    return load_aux(L, status, env);
  }
  
  /* }====================================================== */
  
  
  static int dofilecont (lua_State *L, int d1, lua_KContext d2) {
    (void)d1;  (void)d2;  /* only to match 'lua_Kfunction' prototype */
    return lua_gettop(L) - 1;
  }
  
  
  static int luaB_dofile (lua_State *L) {
    const char *fname = luaL_optstring(L, 1, NULL);
    lua_settop(L, 1);
    if (l_unlikely(luaL_loadfile(L, fname) != LUA_OK))
      return lua_error(L);
    lua_callk(L, 0, LUA_MULTRET, 0, dofilecont);
    return dofilecont(L, 0, 0);
  }
  
  
  static int luaB_assert (lua_State *L) {
    if (l_likely(lua_toboolean(L, 1)))  /* condition is true? */
      return lua_gettop(L);  /* return all arguments */
    else {  /* error */
      luaL_checkany(L, 1);  /* there must be a condition */
      lua_remove(L, 1);  /* remove it */
      lua_pushliteral(L, "assertion failed!");  /* default message */
      lua_settop(L, 1);  /* leave only message (default if no other one) */
      return luaB_error(L);  /* call 'error' */
    }
  }
  
  
  static int luaB_select (lua_State *L) {
    int n = lua_gettop(L);
    if (lua_type(L, 1) == LUA_TSTRING && *lua_tostring(L, 1) == '#') {
      lua_pushinteger(L, n-1);
      return 1;
    }
    else {
      lua_Integer i = luaL_checkinteger(L, 1);
      if (i < 0) i = n + i;
      else if (i > n) i = n;
      luaL_argcheck(L, 1 <= i, 1, "index out of range");
      return n - (int)i;
    }
  }
  
  
  /*
  ** Continuation function for 'pcall' and 'xpcall'. Both functions
  ** already pushed a 'true' before doing the call, so in case of success
  ** 'finishpcall' only has to return everything in the stack minus
  ** 'extra' values (where 'extra' is exactly the number of items to be
  ** ignored).
  */
  static int finishpcall (lua_State *L, int status, lua_KContext extra) {
    if (l_unlikely(status != LUA_OK && status != LUA_YIELD)) {  /* error? */
      lua_pushboolean(L, 0);  /* first result (false) */
      lua_pushvalue(L, -2);  /* error message */
      return 2;  /* return false, msg */
    }
    else
      return lua_gettop(L) - (int)extra;  /* return all results */
  }
  
  
  static int luaB_pcall (lua_State *L) {
    int status;
    luaL_checkany(L, 1);
    lua_pushboolean(L, 1);  /* first result if no errors */
    lua_insert(L, 1);  /* put it in place */
    status = lua_pcallk(L, lua_gettop(L) - 2, LUA_MULTRET, 0, 0, finishpcall);
    return finishpcall(L, status, 0);
  }
  
  
  /*
  ** Do a protected call with error handling. After 'lua_rotate', the
  ** stack will have <f, err, true, f, [args...]>; so, the function passes
  ** 2 to 'finishpcall' to skip the 2 first values when returning results.
  */
  static int luaB_xpcall (lua_State *L) {
    int status;
    int n = lua_gettop(L);
    luaL_checktype(L, 2, LUA_TFUNCTION);  /* check error function */
    lua_pushboolean(L, 1);  /* first result */
    lua_pushvalue(L, 1);  /* function */
    lua_rotate(L, 3, 2);  /* move them below function's arguments */
    status = lua_pcallk(L, n - 2, LUA_MULTRET, 2, 2, finishpcall);
    return finishpcall(L, status, 2);
  }
  
  
  static int luaB_tostring (lua_State *L) {
    luaL_checkany(L, 1);
    luaL_tolstring(L, 1, NULL);
    return 1;
  }
  
  
  static const luaL_Reg base_funcs[] = {
    {"assert", luaB_assert},
    {"error", luaB_error},
    {"getmetatable", luaB_getmetatable},
    {"ipairs", luaB_ipairs},
    {"load", luaB_load},
    {"next", luaB_next},
    {"pairs", luaB_pairs},
    {"pcall", luaB_pcall},
    {"warn", luaB_warn},
    {"rawequal", luaB_rawequal},
    {"rawlen", luaB_rawlen},
    {"rawget", luaB_rawget},
    {"rawset", luaB_rawset},
    {"select", luaB_select},
    {"setmetatable", luaB_setmetatable},
    {"tonumber", luaB_tonumber},
    {"tostring", luaB_tostring},
    {"type", luaB_type},
    {"xpcall", luaB_xpcall},
    /* placeholders */
    {LUA_GNAME, NULL},
    {"_VERSION", NULL},
    {NULL, NULL}
  };
  
  
  LUAMOD_API int luaopen_base (lua_State *L) {
    /* open lib into global table */
    lua_pushglobaltable(L);
    luaL_setfuncs(L, base_funcs, 0);
    /* set global _G */
    lua_pushvalue(L, -1);
    lua_setfield(L, -2, LUA_GNAME);
    /* set global _VERSION */
    lua_pushliteral(L, LUA_VERSION);
    lua_setfield(L, -2, "_VERSION");
    return 1;
  }
  
  