lua/lapi.c

/*
** $Id: lapi.c,v 1.77 2000/03/29 20:19:20 roberto Exp roberto $
** Lua API
** See Copyright Notice in lua.h
*/


#include <string.h>

#define LUA_REENTRANT

#include "lapi.h"
#include "lauxlib.h"
#include "ldo.h"
#include "lfunc.h"
#include "lgc.h"
#include "lmem.h"
#include "lobject.h"
#include "lref.h"
#include "lstate.h"
#include "lstring.h"
#include "ltable.h"
#include "ltm.h"
#include "lua.h"
#include "lvm.h"


const char lua_ident[] = "$Lua: " LUA_VERSION " " LUA_COPYRIGHT " $\n"
                               "$Authors: " LUA_AUTHORS " $";



void luaA_checkCargs (lua_State *L, int nargs) {
  if (nargs > L->top-L->Cstack.base)
    luaL_verror(L, "Lua API error - "
                   "expected at least %d arguments in C2lua stack", nargs);
}


lua_Object luaA_putluaObject (lua_State *L, const TObject *o) {
  luaD_openstack(L, L->Cstack.base);
  *L->Cstack.base++ = *o;
  return L->Cstack.base-1;
}


lua_Object luaA_putObjectOnTop (lua_State *L) {
  luaD_openstack(L, L->Cstack.base);
  *L->Cstack.base++ = *(--L->top);
  return L->Cstack.base-1;
}


static void top2LC (lua_State *L, int n) {
  /* Put the `n' elements on the top as the Lua2C contents */
  L->Cstack.base = L->top;  /* new base */
  L->Cstack.lua2C = L->Cstack.base-n;  /* position of the new results */
  L->Cstack.num = n;  /* number of results */
}


lua_Object lua_pop (lua_State *L) {
  luaA_checkCargs(L, 1);
  return luaA_putObjectOnTop(L);
}


/*
** Get a parameter, returning the object handle or LUA_NOOBJECT on error.
** `number' must be 1 to get the first parameter.
*/
lua_Object lua_lua2C (lua_State *L, int number) {
  if (number <= 0 || number > L->Cstack.num) return LUA_NOOBJECT;
  return L->Cstack.lua2C+number-1;
}


int lua_callfunction (lua_State *L, lua_Object function) {
  if (function == LUA_NOOBJECT)
    return 1;
  else {
    luaD_openstack(L, L->Cstack.base);
    *L->Cstack.base = *function;
    return luaD_protectedrun(L);
  }
}


lua_Object lua_gettagmethod (lua_State *L, int tag, const char *event) {
  return luaA_putluaObject(L, luaT_gettagmethod(L, tag, event));
}


lua_Object lua_settagmethod (lua_State *L, int tag, const char *event) {
  TObject *method;
  luaA_checkCargs(L, 1);
  method = L->top-1;
  if ((ttype(method) != TAG_NIL) && (*lua_type(L, method) != 'f'))
    lua_error(L, "Lua API error - tag method must be a function or nil");
  luaT_settagmethod(L, tag, event, method);
  return luaA_putObjectOnTop(L);
}


lua_Object lua_gettable (lua_State *L) {
  luaA_checkCargs(L, 2);
  luaV_gettable(L, L->top--);
  return luaA_putObjectOnTop(L);
}


lua_Object lua_rawgettable (lua_State *L) {
  lua_Object res;
  luaA_checkCargs(L, 2);
  if (ttype(L->top-2) != TAG_TABLE)
    lua_error(L, "indexed expression not a table in rawgettable");
  res = luaA_putluaObject(L, luaH_get(L, avalue(L->top-2), L->top-1));
  L->top -= 2;
  return res;
}


void lua_settable (lua_State *L) {
  StkId top;
  luaA_checkCargs(L, 3);
  top = L->top;
  luaV_settable(L, top-3, top);
  L->top = top-3;  /* pop table, index, and value */
}


void lua_rawsettable (lua_State *L) {
  luaA_checkCargs(L, 3);
  luaV_rawsettable(L, L->top-3);
}


lua_Object lua_createtable (lua_State *L) {
  TObject o;
  luaC_checkGC(L);
  avalue(&o) = luaH_new(L, 0);
  ttype(&o) = TAG_TABLE;
  return luaA_putluaObject(L, &o);
}


lua_Object lua_getglobal (lua_State *L, const char *name) {
  luaV_getglobal(L, luaS_assertglobalbyname(L, name), L->top++);
  return luaA_putObjectOnTop(L);
}


lua_Object lua_rawgetglobal (lua_State *L, const char *name) {
  GlobalVar *gv = luaS_assertglobalbyname(L, name);
  return luaA_putluaObject(L, &gv->value);
}


void lua_setglobal (lua_State *L, const char *name) {
  luaA_checkCargs(L, 1);
  luaV_setglobal(L, luaS_assertglobalbyname(L, name), L->top--);
}


void lua_rawsetglobal (lua_State *L, const char *name) {
  GlobalVar *gv = luaS_assertglobalbyname(L, name);
  luaA_checkCargs(L, 1);
  gv->value = *(--L->top);
}


const char *lua_type (lua_State *L, lua_Object o) {
  UNUSED(L);
  return (o == LUA_NOOBJECT) ? "NOOBJECT" : luaO_typename(o);
}

int lua_isnil (lua_State *L, lua_Object o) {
  UNUSED(L);
  return (o != LUA_NOOBJECT) && (ttype(o) == TAG_NIL);
}

int lua_istable (lua_State *L, lua_Object o) {
  UNUSED(L);
  return (o != LUA_NOOBJECT) && (ttype(o) == TAG_TABLE);
}

int lua_isuserdata (lua_State *L, lua_Object o) {
  UNUSED(L);
  return (o != LUA_NOOBJECT) && (ttype(o) == TAG_USERDATA);
}

int lua_iscfunction (lua_State *L, lua_Object o) {
  UNUSED(L);
  return (o != LUA_NOOBJECT) && (ttype(o) == TAG_CCLOSURE);
}

int lua_isnumber (lua_State *L, lua_Object o) {
  UNUSED(L);
  return (o != LUA_NOOBJECT) && (tonumber(o) == 0);
}

int lua_isstring (lua_State *L, lua_Object o) {
  UNUSED(L);
  return (o != LUA_NOOBJECT && (ttype(o) == TAG_STRING ||
                                ttype(o) == TAG_NUMBER));
}

int lua_isfunction (lua_State *L, lua_Object o) {
  return *lua_type(L, o) == 'f';
}

int lua_equal(lua_State *L, lua_Object o1, lua_Object o2) {
  UNUSED(L);
  if (o1 == LUA_NOOBJECT || o2 == LUA_NOOBJECT)
    return (o1 == o2);
  else return luaO_equalObj(o1, o2);
}


double lua_getnumber (lua_State *L, lua_Object obj) {
  UNUSED(L);
  if (obj == LUA_NOOBJECT  || tonumber(obj))
     return 0.0;
  else return (nvalue(obj));
}

const char *lua_getstring (lua_State *L, lua_Object obj) {
  luaC_checkGC(L);  /* `tostring' may create a new string */
  if (obj == LUA_NOOBJECT || tostring(L, obj))
    return NULL;
  else return (svalue(obj));
}

long lua_strlen (lua_State *L, lua_Object obj) {
  if (obj == LUA_NOOBJECT || tostring(L, obj))
    return 0L;
  else return (tsvalue(obj)->u.s.len);
}

void *lua_getuserdata (lua_State *L, lua_Object obj) {
  UNUSED(L);
  if (obj == LUA_NOOBJECT || ttype(obj) != TAG_USERDATA)
    return NULL;
  else return tsvalue(obj)->u.d.value;
}

lua_CFunction lua_getcfunction (lua_State *L, lua_Object obj) {
  if (!lua_iscfunction(L, obj))
    return NULL;
  else return clvalue(obj)->f.c;
}


void lua_pushnil (lua_State *L) {
  ttype(L->top) = TAG_NIL;
  incr_top;
}

void lua_pushnumber (lua_State *L, double n) {
  ttype(L->top) = TAG_NUMBER;
  nvalue(L->top) = n;
  incr_top;
}

void lua_pushlstring (lua_State *L, const char *s, long len) {
  tsvalue(L->top) = luaS_newlstr(L, s, len);
  ttype(L->top) = TAG_STRING;
  incr_top;
  luaC_checkGC(L);
}

void lua_pushstring (lua_State *L, const char *s) {
  if (s == NULL)
    lua_pushnil(L);
  else
    lua_pushlstring(L, s, strlen(s));
}

void lua_pushcclosure (lua_State *L, lua_CFunction fn, int n) {
  if (fn == NULL)
    lua_error(L, "Lua API error - attempt to push a NULL Cfunction");
  luaA_checkCargs(L, n);
  luaV_Cclosure(L, fn, n);
  luaC_checkGC(L);
}

void lua_pushusertag (lua_State *L, void *u, int tag) {  /* ORDER LUA_T */
  if (tag != LUA_ANYTAG && tag != TAG_USERDATA && tag < NUM_TAGS)
    luaL_verror(L, "invalid tag for a userdata (%d)", tag);
  tsvalue(L->top) = luaS_createudata(L, u, tag);
  ttype(L->top) = TAG_USERDATA;
  incr_top;
  luaC_checkGC(L);
}

void luaA_pushobject (lua_State *L, const TObject *o) {
  *L->top = *o;
  incr_top;
}

void lua_pushobject (lua_State *L, lua_Object o) {
  if (o == LUA_NOOBJECT)
    lua_error(L, "Lua API error - attempt to push a NOOBJECT");
  *L->top = *o;
  incr_top;
}


int lua_tag (lua_State *L, lua_Object o) {
  if (o == LUA_NOOBJECT)
    return TAG_NIL;
  else if (ttype(o) == TAG_USERDATA)  /* to allow `old' tags (deprecated) */
    return o->value.ts->u.d.tag;
  else
    return luaT_effectivetag(L, o);
}


void lua_settag (lua_State *L, int tag) {
  luaA_checkCargs(L, 1);
  luaT_realtag(L, tag);
  switch (ttype(L->top-1)) {
    case TAG_TABLE:
      (L->top-1)->value.a->htag = tag;
      break;
    case TAG_USERDATA:
      (L->top-1)->value.ts->u.d.tag = tag;
      break;
    default:
      luaL_verror(L, "cannot change the tag of a %.20s",
                  luaO_typename(L->top-1));
  }
  L->top--;
}


GlobalVar *luaA_nextvar (lua_State *L, TString *ts) {
  GlobalVar *gv;
  if (ts == NULL)
    gv = L->rootglobal;  /* first variable */
  else {
    /* check whether name is in global var list */
    luaL_arg_check(L, ts->u.s.gv, 1, "variable name expected");
    gv = ts->u.s.gv->next;  /* get next */
  }
  while (gv && gv->value.ttype == TAG_NIL)  /* skip globals with nil */
    gv = gv->next;
  if (gv) {
    ttype(L->top) = TAG_STRING; tsvalue(L->top) = gv->name;
    incr_top;
    luaA_pushobject(L, &gv->value);
  }
  return gv;
}


const char *lua_nextvar (lua_State *L, const char *varname) {
  TString *ts = (varname == NULL) ? NULL : luaS_new(L, varname);
  GlobalVar *gv = luaA_nextvar(L, ts);
  if (gv) {
    top2LC(L, 2);
    return gv->name->str;
  }
  else {
    top2LC(L, 0);
    return NULL;
  }
}


int luaA_next (lua_State *L, const Hash *t, int i) {
  int tsize = t->size;
  for (; i<tsize; i++) {
    Node *n = node(t, i);
    if (ttype(val(n)) != TAG_NIL) {
      luaA_pushobject(L, key(n));
      luaA_pushobject(L, val(n));
      return i+1;  /* index to be used next time */
    }
  }
  return 0;  /* no more elements */
}


int lua_next (lua_State *L, lua_Object t, int i) {
  if (ttype(t) != TAG_TABLE)
    lua_error(L, "Lua API error - object is not a table in `lua_next'"); 
  i = luaA_next(L, avalue(t), i);
  top2LC(L, (i==0) ? 0 : 2);
  return i;
}