/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- */

/*  Libnul - Another Utility Library
 *  Copyright (C) 2008  Søren Sandmann
 *
 *  This library is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU Library General Public
 *  License as published by the Free Software Foundation; either
 *  version 2 of the License, or (at your option) any later version.
 *
 *  This library is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 *  Library General Public License for more details.
 *
 *  You should have received a copy of the GNU Library General Public
 *  License along with this library; if not, write to the 
 *  Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 *  Boston, MA  02111-1307, USA.
 */

#include <stdlib.h>
#include <assert.h>
#include <string.h>
#include <stdio.h>
#include "ffi.h"
#include "libnul.h"

struct nul_fun_def_t
{
    int		n_args;
    ffi_type   *ffi_ret_type;
    ffi_type  **ffi_arg_types;
    ffi_cif	ffi_cif;
};

static ffi_type *
ffi_type_from_type (nul_type_t type)
{
    switch (type)
    {
    case NUL_TYPE_UINT32: return &ffi_type_uint32;
    case NUL_TYPE_INT32: return &ffi_type_sint32;
    case NUL_TYPE_UINT16: return &ffi_type_uint16;
    case NUL_TYPE_INT16: return &ffi_type_sint16;
    case NUL_TYPE_UINT8: return &ffi_type_uint8;
    case NUL_TYPE_INT8: return &ffi_type_sint8;
	
    case NUL_TYPE_UINT: return &ffi_type_uint;
    case NUL_TYPE_INT: return &ffi_type_sint;
    case NUL_TYPE_USHORT: return &ffi_type_ushort;
    case NUL_TYPE_SHORT: return &ffi_type_sshort;
	
    case NUL_TYPE_UCHAR: return &ffi_type_uchar;
    case NUL_TYPE_SCHAR: return &ffi_type_schar;
#ifdef __CHAR_UNSIGNED__
    case NUL_TYPE_CHAR: return &ffi_type_uchar;
#else
    case NUL_TYPE_CHAR: return &ffi_type_schar;
#endif
	
    case NUL_TYPE_POINTER: return &ffi_type_pointer;
    case NUL_TYPE_STRING: return &ffi_type_pointer;
	
    case NUL_TYPE_DOUBLE: return &ffi_type_double;
    case NUL_TYPE_FLOAT: return &ffi_type_float;

    case NUL_TYPE_VOID: return &ffi_type_void;
    default:
	return NULL;
    }
}

nul_fun_def_t *
nul_fun_def_new (nul_type_t      ret_type,
		 int             n_args,
		 nul_type_t     *arg_types)
{
    nul_fun_def_t *def = malloc (sizeof (nul_fun_def_t));
    int i;
    
    if (!def)
	return NULL;

    def->ffi_arg_types = malloc (sizeof (ffi_type *) * n_args);
    if (!def->ffi_arg_types)
    {
	free (def);
	return NULL;
    }

    for (i = 0; i < n_args; ++i)
    {
	if (arg_types[i] == NUL_TYPE_VOID)
	    g_error ("Arguments tuments cannot have type void");
	else
	    def->ffi_arg_types[i] = ffi_type_from_type (arg_types[i]);
    }

    def->ffi_ret_type = ffi_type_from_type (ret_type);
    
    def->n_args = n_args;

    ffi_prep_cif (&def->ffi_cif, FFI_DEFAULT_ABI, n_args, def->ffi_ret_type, def->ffi_arg_types);
    
    return def;
}

nul_arg_t
nul_fun_def_invoke (nul_fun_def_t   *fun,
		    nul_function_t  f,
		    nul_arg_t      *args)
{
    void *stack_args[8];
    void **ffi_args;
    nul_arg_t ret;
    int i;

    if (fun->n_args > 8)
	ffi_args = malloc (fun->n_args * sizeof (void *));
    else
	ffi_args = stack_args;
    
    for (i = 0; i < fun->n_args; ++i)
	ffi_args[i] = &(args[i]);

    ffi_call (&(fun->ffi_cif), f, &ret, ffi_args);

    if (ffi_args != stack_args)
	free (ffi_args);
    
    return ret;
}

void
nul_fun_def_free (nul_fun_def_t *fun)
{
    free (fun->ffi_arg_types);
    free (fun);
}