LuaJIT/src/lib_ffi.c

/*
** FFI library.
** Copyright (C) 2005-2010 Mike Pall. See Copyright Notice in luajit.h
*/

#define lib_ffi_c
#define LUA_LIB

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

#include "lj_obj.h"

#if LJ_HASFFI

#include "lj_gc.h"
#include "lj_err.h"
#include "lj_str.h"
#include "lj_ctype.h"
#include "lj_cparse.h"
#include "lj_cdata.h"
#include "lj_cconv.h"
#include "lj_lib.h"

/* -- C type checks ------------------------------------------------------- */

/* Check first argument for a C type and returns its ID. */
static CTypeID ffi_checkctype(lua_State *L, CTState *cts)
{
  TValue *o = L->base;
  if (!(o < L->top)) {
  err_argtype:
    lj_err_argtype(L, 1, "C type");
  }
  if (tvisstr(o)) {  /* Parse an abstract C type declaration. */
    GCstr *s = strV(o);
    CPState cp;
    int errcode;
    cp.L = L;
    cp.cts = cts;
    cp.srcname = strdata(s);
    cp.p = strdata(s);
    cp.mode = CPARSE_MODE_ABSTRACT|CPARSE_MODE_NOIMPLICIT;
    errcode = lj_cparse(&cp);
    if (errcode) lj_err_throw(L, errcode);  /* Propagate errors. */
    return cp.val.id;
  } else {
    GCcdata *cd;
    if (!tviscdata(o)) goto err_argtype;
    cd = cdataV(o);
    return cd->typeid == CTID_CTYPEID ? *(CTypeID *)cdataptr(cd) : cd->typeid;
  }
}

/* Check argument for C data and return it. */
static GCcdata *ffi_checkcdata(lua_State *L, int narg)
{
  TValue *o = L->base + narg-1;
  if (!(o < L->top && tviscdata(o)))
    lj_err_argt(L, narg, LUA_TCDATA);
  return cdataV(o);
}

/* Convert argument to C pointer. */
static void *ffi_checkptr(lua_State *L, int narg, CTypeID id)
{
  CTState *cts = ctype_cts(L);
  TValue *o = L->base + narg-1;
  void *p;
  if (o >= L->top)
    lj_err_arg(L, narg, LJ_ERR_NOVAL);
  lj_cconv_ct_tv(cts, ctype_get(cts, id), (uint8_t *)&p, o, 0);
  return p;
}

/* -- C type metamethods -------------------------------------------------- */

#define LJLIB_MODULE_ffi_meta

LJLIB_CF(ffi_meta___index)	LJLIB_REC(cdata_index 0)
{
  CTState *cts = ctype_cts(L);
  CTInfo qual = 0;
  CType *ct;
  uint8_t *p;
  TValue *o = L->base;
  if (!(o+1 < L->top && tviscdata(o)))  /* Also checks for presence of key. */
    lj_err_argt(L, 1, LUA_TCDATA);
  ct = lj_cdata_index(cts, cdataV(o), o+1, &p, &qual);
  lj_cdata_get(cts, ct, L->top-1, p);
  return 1;
}

LJLIB_CF(ffi_meta___newindex)	LJLIB_REC(cdata_index 1)
{
  CTState *cts = ctype_cts(L);
  CTInfo qual = 0;
  CType *ct;
  uint8_t *p;
  TValue *o = L->base;
  if (!(o+2 < L->top && tviscdata(o)))  /* Also checks for key and value. */
    lj_err_argt(L, 1, LUA_TCDATA);
  ct = lj_cdata_index(cts, cdataV(o), o+1, &p, &qual);
  lj_cdata_set(cts, ct, p, o+2, qual);
  return 0;
}

/* Forward declaration. */
static int lj_cf_ffi_new(lua_State *L);

LJLIB_CF(ffi_meta___call)	LJLIB_REC(cdata_call)
{
  GCcdata *cd = ffi_checkcdata(L, 1);
  if (cd->typeid == CTID_CTYPEID)
    return lj_cf_ffi_new(L);
  lj_err_caller(L, LJ_ERR_FFI_NYICALL);
  return 0;  /* unreachable */
}

LJLIB_CF(ffi_meta___tostring)
{
  GCcdata *cd = ffi_checkcdata(L, 1);
  const char *msg = "cdata<%s>: %p";
  CTypeID id = cd->typeid;
  if (id == CTID_CTYPEID) {
    msg = "ctype<%s>";
    id = *(CTypeID *)cdataptr(cd);
  } else {
    CType *ct = ctype_raw(ctype_cts(L), id);
    if (ctype_iscomplex(ct->info)) {
      setstrV(L, L->top-1, lj_ctype_repr_complex(L, cdataptr(cd), ct->size));
      return 1;
    } else if (ct->size == 8 && ctype_isinteger(ct->info)) {
      setstrV(L, L->top-1, lj_ctype_repr_int64(L, *(uint64_t *)cdataptr(cd),
					       (ct->info & CTF_UNSIGNED)));
      return 1;
    }
  }
  lj_str_pushf(L, msg, strdata(lj_ctype_repr(L, id, NULL)), cdataptr(cd));
  return 1;
}

#include "lj_libdef.h"

/* -- FFI library functions ----------------------------------------------- */

#define LJLIB_MODULE_ffi

LJLIB_CF(ffi_cdef)
{
  GCstr *s = lj_lib_checkstr(L, 1);
  CPState cp;
  int errcode;
  cp.L = L;
  cp.cts = ctype_cts(L);
  cp.srcname = strdata(s);
  cp.p = strdata(s);
  cp.mode = CPARSE_MODE_MULTI|CPARSE_MODE_DIRECT;
  errcode = lj_cparse(&cp);
  if (errcode) lj_err_throw(L, errcode);  /* Propagate errors. */
  lj_gc_check(L);
  return 0;
}

LJLIB_CF(ffi_new)	LJLIB_REC(.)
{
  CTState *cts = ctype_cts(L);
  CTypeID id = ffi_checkctype(L, cts);
  CTSize sz;
  CTInfo info = lj_ctype_info(cts, id, &sz);
  TValue *o = L->base+1;
  GCcdata *cd;
  if ((info & CTF_VLA)) {
    o++;
    sz = lj_ctype_vlsize(cts, ctype_raw(cts, id),
			 (CTSize)lj_lib_checkint(L, 2));
  }
  if (sz == CTSIZE_INVALID)
    lj_err_arg(L, 1, LJ_ERR_FFI_INVSIZE);
  if (!(info & CTF_VLA) && ctype_align(info) <= CT_MEMALIGN)
    cd = lj_cdata_new(cts, id, sz);
  else
    cd = lj_cdata_newv(cts, id, sz, ctype_align(info));
  setcdataV(L, o-1, cd);  /* Anchor the uninitialized cdata. */
  lj_cconv_ct_init(cts, ctype_raw(cts, id), sz, cdataptr(cd),
		   o, (MSize)(L->top - o));  /* Initialize cdata. */
  L->top = o;  /* Only return the cdata itself. */
  lj_gc_check(L);
  return 1;
}

LJLIB_CF(ffi_typeof)
{
  CTState *cts = ctype_cts(L);
  CTypeID id = ffi_checkctype(L, cts);
  GCcdata *cd = lj_cdata_new(cts, CTID_CTYPEID, 4);
  *(CTypeID *)cdataptr(cd) = id;
  setcdataV(L, L->top-1, cd);
  return 1;
}

LJLIB_CF(ffi_sizeof)
{
  CTState *cts = ctype_cts(L);
  CTypeID id = ffi_checkctype(L, cts);
  CTSize sz;
  if (LJ_UNLIKELY(tviscdata(L->base) && cdataisv(cdataV(L->base)))) {
    sz = cdatavlen(cdataV(L->base));
  } else {
    CType *ct = lj_ctype_rawref(cts, id);
    if (ctype_isvltype(ct->info))
      sz = lj_ctype_vlsize(cts, ct, (CTSize)lj_lib_checkint(L, 2));
    else
      sz = ctype_hassize(ct->info) ? ct->size : CTSIZE_INVALID;
    if (LJ_UNLIKELY(sz == CTSIZE_INVALID)) {
      setnilV(L->top-1);
      return 1;
    }
  }
  setintV(L->top-1, (int32_t)sz);
  return 1;
}

LJLIB_CF(ffi_alignof)
{
  CTState *cts = ctype_cts(L);
  CTypeID id = ffi_checkctype(L, cts);
  CTSize sz = 0;
  CTInfo info = lj_ctype_info(cts, id, &sz);
  setintV(L->top-1, 1 << ctype_align(info));
  return 1;
}

LJLIB_CF(ffi_offsetof)
{
  CTState *cts = ctype_cts(L);
  CTypeID id = ffi_checkctype(L, cts);
  GCstr *name = lj_lib_checkstr(L, 2);
  CType *ct = lj_ctype_rawref(cts, id);
  CTSize ofs;
  if (ctype_isstruct(ct->info) && ct->size != CTSIZE_INVALID) {
    CType *fct = lj_ctype_getfield(cts, ct, name, &ofs);
    if (fct) {
      setintV(L->top-1, ofs);
      if (ctype_isfield(fct->info)) {
	return 1;
      } else if (ctype_isbitfield(fct->info)) {
	setintV(L->top++, ctype_bitpos(fct->info));
	setintV(L->top++, ctype_bitbsz(fct->info));
	return 3;
      }
    }
  }
  return 0;
}

LJLIB_CF(ffi_cast)
{
  CTState *cts = ctype_cts(L);
  CTypeID id = ffi_checkctype(L, cts);
  TValue *o = lj_lib_checkany(L, 2);
  L->top = o+1;  /* Make sure this is the last item on the stack. */
  if (!(tviscdata(o) && cdataV(o)->typeid == id)) {
    CTSize sz = lj_ctype_size(cts, id);
    GCcdata *cd;
    if (sz == CTSIZE_INVALID)
      lj_err_caller(L, LJ_ERR_FFI_INVSIZE);
    cd = lj_cdata_new(cts, id, sz);  /* Create destination cdata. */
    lj_cconv_ct_tv(cts, ctype_raw(cts, id), cdataptr(cd), o, CCF_CAST);
    setcdataV(L, o, cd);
    lj_gc_check(L);
  }
  return 1;
}

LJLIB_CF(ffi_string)
{
  CTState *cts = ctype_cts(L);
  TValue *o = lj_lib_checkany(L, 1);
  size_t sz = (size_t)(CTSize)lj_lib_optint(L, 2, (int32_t)CTSIZE_INVALID);
  CType *ct = ctype_get(cts, sz==CTSIZE_INVALID ? CTID_P_CVOID : CTID_P_CCHAR);
  const char *p;
  L->top = o+1;  /* Make sure this is the last item on the stack. */
  lj_cconv_ct_tv(cts, ct, (uint8_t *)&p, o, 0);
  if (sz == CTSIZE_INVALID) sz = strlen(p);
  setstrV(L, o, lj_str_new(L, p, sz));
  lj_gc_check(L);
  return 1;
}

LJLIB_CF(ffi_copy)
{
  void *dp = ffi_checkptr(L, 1, CTID_P_VOID);
  void *sp = ffi_checkptr(L, 2, CTID_P_CVOID);
  TValue *o = L->base+1;
  CTSize sz;
  if (tvisstr(o) && o+1 >= L->top) {
    sz = strV(o)->len+1;  /* Copy Lua string including trailing '\0'. */
  } else {
    sz = (CTSize)lj_lib_checkint(L, 3);
    if (tvisstr(o) && sz > strV(o)->len+1)
      sz = strV(o)->len+1;  /* Max. copy length is string length. */
  }
  memcpy(dp, sp, sz);
  return 0;
}

LJLIB_CF(ffi_fill)
{
  void *dp = ffi_checkptr(L, 1, CTID_P_VOID);
  CTSize sz = (CTSize)lj_lib_checkint(L, 2);
  int32_t fill = lj_lib_optint(L, 3, 0);
  memset(dp, fill, sz);
  return 0;
}

#define H_(le, be)	LJ_ENDIAN_SELECT(0x##le, 0x##be)

/* Test ABI string. */
LJLIB_CF(ffi_abi)
{
  GCstr *s = lj_lib_checkstr(L, 1);
  int b = 0;
  switch (s->hash) {
#if LJ_64
  case H_(849858eb,ad35fd06): b = 1; break;  /* 64bit */
#else
  case H_(662d3c79,d0e22477): b = 1; break;  /* 32bit */
#endif
#if LJ_ARCH_HASFPU
  case H_(e33ee463,e33ee463): b = 1; break;  /* fpu */
#endif
#if LJ_ABI_SOFTFP
  case H_(61211a23,c2e8c81c): b = 1; break;  /* softfp */
#else
  case H_(539417a8,8ce0812f): b = 1; break;  /* hardfp */
#endif
#if LJ_ABI_EABI
  case H_(2182df8f,f2ed1152): b = 1; break;  /* eabi */
#endif
#if LJ_ABI_WIN
  case H_(4ab624a8,4ab624a8): b = 1; break;  /* win */
#endif
  case H_(3af93066,1f001464): b = 1; break;  /* le/be */
  default:
    break;
  }
  setboolV(L->top-1, b);
  return 1;
}

#undef H_

LJLIB_PUSH(top-3) LJLIB_SET(os)
LJLIB_PUSH(top-2) LJLIB_SET(arch)

#include "lj_libdef.h"

/* ------------------------------------------------------------------------ */

LUALIB_API int luaopen_ffi(lua_State *L)
{
  lj_ctype_init(L);
  LJ_LIB_REG_(L, NULL, ffi_meta);
  /* NOBARRIER: basemt is a GC root. */
  setgcref(basemt_it(G(L), LJ_TCDATA), obj2gco(tabV(L->top-1)));
  lua_pushliteral(L, LJ_OS_NAME);
  lua_pushliteral(L, LJ_ARCH_NAME);
  LJ_LIB_REG_(L, NULL, ffi);  /* Note: no global "ffi" created! */
  return 1;
}

#endif