vlc_variables.h

/*****************************************************************************
 * vlc_variables.h: variables handling
 *****************************************************************************
 * Copyright (C) 2002-2004 VLC authors and VideoLAN
 * $Id$
 *
 * Authors: Samuel Hocevar <sam@zoy.org>
 *          Gildas Bazin <gbazin@netcourrier.com>
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as published by
 * the Free Software Foundation; either version 2.1 of the License, or
 * (at your option) any later version.
 *
 * This program 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 Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston MA 02110-1301, USA.
 *****************************************************************************/

#ifndef VLC_VARIABLES_H
#define VLC_VARIABLES_H 1

/**
 * \file
 * This file defines functions and structures for dynamic variables in vlc
 */

/**
 * \defgroup variables Variables
 *
 * Functions for using the object variables in vlc.
 *
 * Vlc have a very powerful "object variable" infrastructure useful
 * for many things.
 *
 * @{
 */

#define VLC_VAR_TYPE      0x00ff
#define VLC_VAR_CLASS     0x00f0
#define VLC_VAR_FLAGS     0xff00

/**
 * \defgroup var_type Variable types
 * These are the different types a vlc variable can have.
 * @{
 */
#define VLC_VAR_VOID      0x0010
#define VLC_VAR_BOOL      0x0020
#define VLC_VAR_INTEGER   0x0030
#define VLC_VAR_HOTKEY    0x0031
#define VLC_VAR_STRING    0x0040
#define VLC_VAR_VARIABLE  0x0044
#define VLC_VAR_FLOAT     0x0050
#define VLC_VAR_TIME      0x0060
#define VLC_VAR_ADDRESS   0x0070
#define VLC_VAR_COORDS    0x00A0
/**@}*/

/** \defgroup var_flags Additive flags
 * These flags are added to the type field of the variable. Most as a result of
 * a var_Change() call, but some may be added at creation time
 * @{
 */
#define VLC_VAR_HASCHOICE 0x0100
#define VLC_VAR_HASMIN    0x0200
#define VLC_VAR_HASMAX    0x0400
#define VLC_VAR_HASSTEP   0x0800

#define VLC_VAR_ISCOMMAND 0x2000

/** Creation flag */
/* If the variable is not found on the current module
   search all parents and finally module config until found */
#define VLC_VAR_DOINHERIT 0x8000
/**@}*/

/**
 * \defgroup var_action Variable actions
 * These are the different actions that can be used with var_Change().
 * The parameters given are the meaning of the two last parameters of
 * var_Change() when this action is being used.
 * @{
 */

/**
 * Set the minimum value of this variable
 * \param p_val The new minimum value
 * \param p_val2 Unused
 */
#define VLC_VAR_SETMIN              0x0010
/**
 * Set the maximum value of this variable
 * \param p_val The new maximum value
 * \param p_val2 Unused
 */
#define VLC_VAR_SETMAX              0x0011
#define VLC_VAR_SETSTEP             0x0012

/**
 * Set the value of this variable without triggering any callbacks
 * \param p_val The new value
 * \param p_val2 Unused
 */
#define VLC_VAR_SETVALUE            0x0013

#define VLC_VAR_SETTEXT             0x0014
#define VLC_VAR_GETTEXT             0x0015

#define VLC_VAR_GETMIN              0x0016
#define VLC_VAR_GETMAX              0x0017
#define VLC_VAR_GETSTEP             0x0018

#define VLC_VAR_ADDCHOICE           0x0020
#define VLC_VAR_DELCHOICE           0x0021
#define VLC_VAR_CLEARCHOICES        0x0022
#define VLC_VAR_SETDEFAULT          0x0023
#define VLC_VAR_GETCHOICES          0x0024

#define VLC_VAR_CHOICESCOUNT        0x0026

/**@}*/

/** \defgroup var_GetAndSet Variable actions
 * These are the different actions that can be used with var_GetAndSet()
 * @{
 */
enum {
    VLC_VAR_BOOL_TOGGLE, /**< Invert a boolean value (param ignored) */
    VLC_VAR_INTEGER_ADD, /**< Add parameter to an integer value */
    VLC_VAR_INTEGER_OR,  /**< Binary OR over an integer bits field */
    VLC_VAR_INTEGER_NAND,/**< Binary NAND over an integer bits field */
};
/**@}*/

/*****************************************************************************
 * Prototypes
 *****************************************************************************/
VLC_API int var_Create( vlc_object_t *, const char *, int );
#define var_Create(a,b,c) var_Create( VLC_OBJECT(a), b, c )

VLC_API int var_Destroy( vlc_object_t *, const char * );
#define var_Destroy(a,b) var_Destroy( VLC_OBJECT(a), b )

VLC_API int var_Change( vlc_object_t *, const char *, int, vlc_value_t *, vlc_value_t * );
#define var_Change(a,b,c,d,e) var_Change( VLC_OBJECT(a), b, c, d, e )

VLC_API int var_Type( vlc_object_t *, const char * ) VLC_USED;
#define var_Type(a,b) var_Type( VLC_OBJECT(a), b )

VLC_API int var_Set( vlc_object_t *, const char *, vlc_value_t );
#define var_Set(a,b,c) var_Set( VLC_OBJECT(a), b, c )

VLC_API int var_Get( vlc_object_t *, const char *, vlc_value_t * );
#define var_Get(a,b,c) var_Get( VLC_OBJECT(a), b, c )

VLC_API int var_SetChecked( vlc_object_t *, const char *, int, vlc_value_t );
#define var_SetChecked(o,n,t,v) var_SetChecked(VLC_OBJECT(o),n,t,v)
VLC_API int var_GetChecked( vlc_object_t *, const char *, int, vlc_value_t * );
#define var_GetChecked(o,n,t,v) var_GetChecked(VLC_OBJECT(o),n,t,v)
VLC_API int var_GetAndSet( vlc_object_t *, const char *, int, vlc_value_t * );

VLC_API int var_Inherit( vlc_object_t *, const char *, int, vlc_value_t * );

VLC_API void var_FreeList( vlc_value_t *, vlc_value_t * );


/*****************************************************************************
 * Variable callbacks
 *****************************************************************************
 * int MyCallback( vlc_object_t *p_this,
 *                 char const *psz_variable,
 *                 vlc_value_t oldvalue,
 *                 vlc_value_t newvalue,
 *                 void *p_data);
 *****************************************************************************/
VLC_API int var_AddCallback( vlc_object_t *, const char *, vlc_callback_t, void * );
VLC_API int var_DelCallback( vlc_object_t *, const char *, vlc_callback_t, void * );
VLC_API int var_TriggerCallback( vlc_object_t *, const char * );

VLC_API int var_AddListCallback( vlc_object_t *, const char *, vlc_list_callback_t, void * );
VLC_API int var_DelListCallback( vlc_object_t *, const char *, vlc_list_callback_t, void * );

#define var_AddCallback(a,b,c,d) var_AddCallback( VLC_OBJECT(a), b, c, d )
#define var_DelCallback(a,b,c,d) var_DelCallback( VLC_OBJECT(a), b, c, d )
#define var_TriggerCallback(a,b) var_TriggerCallback( VLC_OBJECT(a), b )

#define var_AddListCallback(a,b,c,d) var_AddListCallback( VLC_OBJECT(a), b, c, d )
#define var_DelListCallback(a,b,c,d) var_DelListCallback( VLC_OBJECT(a), b, c, d )

/*****************************************************************************
 * helpers functions
 *****************************************************************************/

/**
 * Set the value of an integer variable
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 * \param i The new integer value of this variable
 */
static inline int var_SetInteger( vlc_object_t *p_obj, const char *psz_name,
                                  int64_t i )
{
    vlc_value_t val;
    val.i_int = i;
    return var_SetChecked( p_obj, psz_name, VLC_VAR_INTEGER, val );
}

/**
 * Set the value of an boolean variable
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 * \param b The new boolean value of this variable
 */
static inline int var_SetBool( vlc_object_t *p_obj, const char *psz_name, bool b )
{
    vlc_value_t val;
    val.b_bool = b;
    return var_SetChecked( p_obj, psz_name, VLC_VAR_BOOL, val );
}

/**
 * Set the value of a time variable
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 * \param i The new time value of this variable
 */
static inline int var_SetTime( vlc_object_t *p_obj, const char *psz_name, int64_t i )
{
    vlc_value_t val;
    val.i_time = i;
    return var_SetChecked( p_obj, psz_name, VLC_VAR_TIME, val );
}

static inline int var_SetCoords( vlc_object_t *obj, const char *name,
                                 int32_t x, int32_t y )
{
    vlc_value_t val;
    val.coords.x = x;
    val.coords.y = y;
    return var_SetChecked (obj, name, VLC_VAR_COORDS, val);
}
#define var_SetCoords(o,n,x,y) var_SetCoords(VLC_OBJECT(o),n,x,y)

/**
 * Set the value of a float variable
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 * \param f The new float value of this variable
 */
static inline int var_SetFloat( vlc_object_t *p_obj, const char *psz_name, float f )
{
    vlc_value_t val;
    val.f_float = f;
    return var_SetChecked( p_obj, psz_name, VLC_VAR_FLOAT, val );
}

/**
 * Set the value of a string variable
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 * \param psz_string The new string value of this variable
 */
static inline int var_SetString( vlc_object_t *p_obj, const char *psz_name, const char *psz_string )
{
    vlc_value_t val;
    val.psz_string = (char *)psz_string;
    return var_SetChecked( p_obj, psz_name, VLC_VAR_STRING, val );
}

/**
 * Set the value of a pointer variable
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 * \param ptr The new pointer value of this variable
 */
static inline
int var_SetAddress( vlc_object_t *p_obj, const char *psz_name, void *ptr )
{
    vlc_value_t val;
    val.p_address = ptr;
    return var_SetChecked( p_obj, psz_name, VLC_VAR_ADDRESS, val );
}

#define var_SetInteger(a,b,c)   var_SetInteger( VLC_OBJECT(a),b,c)
#define var_SetBool(a,b,c)      var_SetBool( VLC_OBJECT(a),b,c)
#define var_SetTime(a,b,c)      var_SetTime( VLC_OBJECT(a),b,c)
#define var_SetFloat(a,b,c)     var_SetFloat( VLC_OBJECT(a),b,c)
#define var_SetString(a,b,c)    var_SetString( VLC_OBJECT(a),b,c)
#define var_SetAddress(o, n, p) var_SetAddress(VLC_OBJECT(o), n, p)


/**
 * Get an integer value
*
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 */
VLC_USED
static inline int64_t var_GetInteger( vlc_object_t *p_obj, const char *psz_name )
{
    vlc_value_t val;
    if( !var_GetChecked( p_obj, psz_name, VLC_VAR_INTEGER, &val ) )
        return val.i_int;
    else
        return 0;
}

/**
 * Get a boolean value
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 */
VLC_USED
static inline bool var_GetBool( vlc_object_t *p_obj, const char *psz_name )
{
    vlc_value_t val; val.b_bool = false;

    if( !var_GetChecked( p_obj, psz_name, VLC_VAR_BOOL, &val ) )
        return val.b_bool;
    else
        return false;
}

/**
 * Get a time value
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 */
VLC_USED
static inline int64_t var_GetTime( vlc_object_t *p_obj, const char *psz_name )
{
    vlc_value_t val; val.i_time = 0L;
    if( !var_GetChecked( p_obj, psz_name, VLC_VAR_TIME, &val ) )
        return val.i_time;
    else
        return 0;
}

static inline void var_GetCoords( vlc_object_t *obj, const char *name,
                                  int32_t *px, int32_t *py )
{
    vlc_value_t val;

    if (likely(!var_GetChecked (obj, name, VLC_VAR_COORDS, &val)))
    {
        *px = val.coords.x;
        *py = val.coords.y;
    }
    else
        *px = *py = 0;
}
#define var_GetCoords(o,n,x,y) var_GetCoords(VLC_OBJECT(o),n,x,y)

/**
 * Get a float value
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 */
VLC_USED
static inline float var_GetFloat( vlc_object_t *p_obj, const char *psz_name )
{
    vlc_value_t val; val.f_float = 0.0;
    if( !var_GetChecked( p_obj, psz_name, VLC_VAR_FLOAT, &val ) )
        return val.f_float;
    else
        return 0.0;
}

/**
 * Get a string value
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 */
VLC_USED VLC_MALLOC
static inline char *var_GetString( vlc_object_t *p_obj, const char *psz_name )
{
    vlc_value_t val; val.psz_string = NULL;
    if( var_GetChecked( p_obj, psz_name, VLC_VAR_STRING, &val ) )
        return NULL;
    else
        return val.psz_string;
}

VLC_USED VLC_MALLOC
static inline char *var_GetNonEmptyString( vlc_object_t *p_obj, const char *psz_name )
{
    vlc_value_t val;
    if( var_GetChecked( p_obj, psz_name, VLC_VAR_STRING, &val ) )
        return NULL;
    if( val.psz_string && *val.psz_string )
        return val.psz_string;
    free( val.psz_string );
    return NULL;
}

VLC_USED
static inline void *var_GetAddress( vlc_object_t *p_obj, const char *psz_name )
{
    vlc_value_t val;
    if( var_GetChecked( p_obj, psz_name, VLC_VAR_ADDRESS, &val ) )
        return NULL;
    else
        return val.p_address;
}

/**
 * Increment an integer variable
 * \param p_obj the object that holds the variable
 * \param psz_name the name of the variable
 */
static inline int64_t var_IncInteger( vlc_object_t *p_obj, const char *psz_name )
{
    vlc_value_t val;
    val.i_int = 1;
    if( var_GetAndSet( p_obj, psz_name, VLC_VAR_INTEGER_ADD, &val ) )
        return 0;
    return val.i_int;
}
#define var_IncInteger(a,b) var_IncInteger( VLC_OBJECT(a), b )

/**
 * Decrement an integer variable
 * \param p_obj the object that holds the variable
 * \param psz_name the name of the variable
 */
static inline int64_t var_DecInteger( vlc_object_t *p_obj, const char *psz_name )
{
    vlc_value_t val;
    val.i_int = -1;
    if( var_GetAndSet( p_obj, psz_name, VLC_VAR_INTEGER_ADD, &val ) )
        return 0;
    return val.i_int;
}
#define var_DecInteger(a,b) var_DecInteger( VLC_OBJECT(a), b )

static inline uint64_t var_OrInteger( vlc_object_t *obj, const char *name,
                                      unsigned v )
{
    vlc_value_t val;
    val.i_int = v;
    if( var_GetAndSet( obj, name, VLC_VAR_INTEGER_OR, &val ) )
        return 0;
    return val.i_int;
}
#define var_OrInteger(a,b,c) var_OrInteger(VLC_OBJECT(a),b,c)

static inline uint64_t var_NAndInteger( vlc_object_t *obj, const char *name,
                                        unsigned v )
{
    vlc_value_t val;
    val.i_int = v;
    if( var_GetAndSet( obj, name, VLC_VAR_INTEGER_NAND, &val ) )
        return 0;
    return val.i_int;
}
#define var_NAndInteger(a,b,c) var_NAndInteger(VLC_OBJECT(a),b,c)

/**
 * Create a integer variable with inherit and get its value.
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 */
VLC_USED
static inline int64_t var_CreateGetInteger( vlc_object_t *p_obj, const char *psz_name )
{
    var_Create( p_obj, psz_name, VLC_VAR_INTEGER | VLC_VAR_DOINHERIT );
    return var_GetInteger( p_obj, psz_name );
}

/**
 * Create a boolean variable with inherit and get its value.
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 */
VLC_USED
static inline bool var_CreateGetBool( vlc_object_t *p_obj, const char *psz_name )
{
    var_Create( p_obj, psz_name, VLC_VAR_BOOL | VLC_VAR_DOINHERIT );
    return var_GetBool( p_obj, psz_name );
}

/**
 * Create a time variable with inherit and get its value.
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 */
VLC_USED
static inline int64_t var_CreateGetTime( vlc_object_t *p_obj, const char *psz_name )
{
    var_Create( p_obj, psz_name, VLC_VAR_TIME | VLC_VAR_DOINHERIT );
    return var_GetTime( p_obj, psz_name );
}

/**
 * Create a float variable with inherit and get its value.
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 */
VLC_USED
static inline float var_CreateGetFloat( vlc_object_t *p_obj, const char *psz_name )
{
    var_Create( p_obj, psz_name, VLC_VAR_FLOAT | VLC_VAR_DOINHERIT );
    return var_GetFloat( p_obj, psz_name );
}

/**
 * Create a string variable with inherit and get its value.
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 */
VLC_USED VLC_MALLOC
static inline char *var_CreateGetString( vlc_object_t *p_obj,
                                           const char *psz_name )
{
    var_Create( p_obj, psz_name, VLC_VAR_STRING | VLC_VAR_DOINHERIT );
    return var_GetString( p_obj, psz_name );
}

VLC_USED VLC_MALLOC
static inline char *var_CreateGetNonEmptyString( vlc_object_t *p_obj,
                                                   const char *psz_name )
{
    var_Create( p_obj, psz_name, VLC_VAR_STRING | VLC_VAR_DOINHERIT );
    return var_GetNonEmptyString( p_obj, psz_name );
}

/**
 * Create an address variable with inherit and get its value.
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 */
VLC_USED
static inline void *var_CreateGetAddress( vlc_object_t *p_obj,
                                           const char *psz_name )
{
    var_Create( p_obj, psz_name, VLC_VAR_ADDRESS | VLC_VAR_DOINHERIT );
    return var_GetAddress( p_obj, psz_name );
}

#define var_CreateGetInteger(a,b)   var_CreateGetInteger( VLC_OBJECT(a),b)
#define var_CreateGetBool(a,b)   var_CreateGetBool( VLC_OBJECT(a),b)
#define var_CreateGetTime(a,b)   var_CreateGetTime( VLC_OBJECT(a),b)
#define var_CreateGetFloat(a,b)   var_CreateGetFloat( VLC_OBJECT(a),b)
#define var_CreateGetString(a,b)   var_CreateGetString( VLC_OBJECT(a),b)
#define var_CreateGetNonEmptyString(a,b)   var_CreateGetNonEmptyString( VLC_OBJECT(a),b)
#define var_CreateGetAddress(a,b)  var_CreateGetAddress( VLC_OBJECT(a),b)

/**
 * Create a integer command variable with inherit and get its value.
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 */
VLC_USED
static inline int64_t var_CreateGetIntegerCommand( vlc_object_t *p_obj, const char *psz_name )
{
    var_Create( p_obj, psz_name, VLC_VAR_INTEGER | VLC_VAR_DOINHERIT
                                   | VLC_VAR_ISCOMMAND );
    return var_GetInteger( p_obj, psz_name );
}

/**
 * Create a boolean command variable with inherit and get its value.
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 */
VLC_USED
static inline bool var_CreateGetBoolCommand( vlc_object_t *p_obj, const char *psz_name )
{
    var_Create( p_obj, psz_name, VLC_VAR_BOOL | VLC_VAR_DOINHERIT
                                   | VLC_VAR_ISCOMMAND );
    return var_GetBool( p_obj, psz_name );
}

/**
 * Create a time command variable with inherit and get its value.
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 */
VLC_USED
static inline int64_t var_CreateGetTimeCommand( vlc_object_t *p_obj, const char *psz_name )
{
    var_Create( p_obj, psz_name, VLC_VAR_TIME | VLC_VAR_DOINHERIT
                                   | VLC_VAR_ISCOMMAND );
    return var_GetTime( p_obj, psz_name );
}

/**
 * Create a float command variable with inherit and get its value.
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 */
VLC_USED
static inline float var_CreateGetFloatCommand( vlc_object_t *p_obj, const char *psz_name )
{
    var_Create( p_obj, psz_name, VLC_VAR_FLOAT | VLC_VAR_DOINHERIT
                                   | VLC_VAR_ISCOMMAND );
    return var_GetFloat( p_obj, psz_name );
}

/**
 * Create a string command variable with inherit and get its value.
 *
 * \param p_obj The object that holds the variable
 * \param psz_name The name of the variable
 */
VLC_USED VLC_MALLOC
static inline char *var_CreateGetStringCommand( vlc_object_t *p_obj,
                                           const char *psz_name )
{
    var_Create( p_obj, psz_name, VLC_VAR_STRING | VLC_VAR_DOINHERIT
                                   | VLC_VAR_ISCOMMAND );
    return var_GetString( p_obj, psz_name );
}

VLC_USED VLC_MALLOC
static inline char *var_CreateGetNonEmptyStringCommand( vlc_object_t *p_obj,
                                                   const char *psz_name )
{
    var_Create( p_obj, psz_name, VLC_VAR_STRING | VLC_VAR_DOINHERIT
                                   | VLC_VAR_ISCOMMAND );
    return var_GetNonEmptyString( p_obj, psz_name );
}

#define var_CreateGetIntegerCommand(a,b)   var_CreateGetIntegerCommand( VLC_OBJECT(a),b)
#define var_CreateGetBoolCommand(a,b)   var_CreateGetBoolCommand( VLC_OBJECT(a),b)
#define var_CreateGetTimeCommand(a,b)   var_CreateGetTimeCommand( VLC_OBJECT(a),b)
#define var_CreateGetFloatCommand(a,b)   var_CreateGetFloatCommand( VLC_OBJECT(a),b)
#define var_CreateGetStringCommand(a,b)   var_CreateGetStringCommand( VLC_OBJECT(a),b)
#define var_CreateGetNonEmptyStringCommand(a,b)   var_CreateGetNonEmptyStringCommand( VLC_OBJECT(a),b)

VLC_USED
static inline int var_CountChoices( vlc_object_t *p_obj, const char *psz_name )
{
    vlc_value_t count;
    if( var_Change( p_obj, psz_name, VLC_VAR_CHOICESCOUNT, &count, NULL ) )
        return 0;
    return count.i_int;
}
#define var_CountChoices(a,b) var_CountChoices( VLC_OBJECT(a),b)


static inline bool var_ToggleBool( vlc_object_t *p_obj, const char *psz_name )
{
    vlc_value_t val;
    if( var_GetAndSet( p_obj, psz_name, VLC_VAR_BOOL_TOGGLE, &val ) )
        return false;
    return val.b_bool;
}
#define var_ToggleBool(a,b) var_ToggleBool( VLC_OBJECT(a),b )


VLC_USED
static inline bool var_InheritBool( vlc_object_t *obj, const char *name )
{
    vlc_value_t val;

    if( var_Inherit( obj, name, VLC_VAR_BOOL, &val ) )
        val.b_bool = false;
    return val.b_bool;
}
#define var_InheritBool(o, n) var_InheritBool(VLC_OBJECT(o), n)

VLC_USED
static inline int64_t var_InheritInteger( vlc_object_t *obj, const char *name )
{
    vlc_value_t val;

    if( var_Inherit( obj, name, VLC_VAR_INTEGER, &val ) )
        val.i_int = 0;
    return val.i_int;
}
#define var_InheritInteger(o, n) var_InheritInteger(VLC_OBJECT(o), n)

VLC_USED
static inline float var_InheritFloat( vlc_object_t *obj, const char *name )
{
    vlc_value_t val;

    if( var_Inherit( obj, name, VLC_VAR_FLOAT, &val ) )
        val.f_float = 0.;
    return val.f_float;
}
#define var_InheritFloat(o, n) var_InheritFloat(VLC_OBJECT(o), n)

VLC_USED VLC_MALLOC
static inline char *var_InheritString( vlc_object_t *obj, const char *name )
{
    vlc_value_t val;

    if( var_Inherit( obj, name, VLC_VAR_STRING, &val ) )
        val.psz_string = NULL;
    else if( val.psz_string && !*val.psz_string )
    {
        free( val.psz_string );
        val.psz_string = NULL;
    }
    return val.psz_string;
}
#define var_InheritString(o, n) var_InheritString(VLC_OBJECT(o), n)

VLC_USED
static inline mtime_t var_InheritTime( vlc_object_t *obj, const char *name )
{
    vlc_value_t val;

    if( var_Inherit( obj, name, VLC_VAR_TIME, &val ) )
        val.i_time = 0;
    return val.i_time;
}
#define var_InheritTime(o, n) var_InheritTime(VLC_OBJECT(o), n)

VLC_USED
static inline void *var_InheritAddress( vlc_object_t *obj, const char *name )
{
    vlc_value_t val;

    if( var_Inherit( obj, name, VLC_VAR_ADDRESS, &val ) )
        val.p_address = NULL;
    return val.p_address;
}
#define var_InheritAddress(o, n) var_InheritAddress(VLC_OBJECT(o), n)

VLC_API int var_InheritURational( vlc_object_t *, unsigned *num, unsigned *den, const char *var );
#define var_InheritURational(a,b,c,d) var_InheritURational(VLC_OBJECT(a), b, c, d)

#define var_GetInteger(a,b)   var_GetInteger( VLC_OBJECT(a),b)
#define var_GetBool(a,b)   var_GetBool( VLC_OBJECT(a),b)
#define var_GetTime(a,b)   var_GetTime( VLC_OBJECT(a),b)
#define var_GetFloat(a,b)   var_GetFloat( VLC_OBJECT(a),b)
#define var_GetString(a,b)   var_GetString( VLC_OBJECT(a),b)
#define var_GetNonEmptyString(a,b)   var_GetNonEmptyString( VLC_OBJECT(a),b)
#define var_GetAddress(a,b)  var_GetAddress( VLC_OBJECT(a),b)

VLC_API int var_LocationParse(vlc_object_t *, const char *mrl, const char *prefix);
#define var_LocationParse(o, m, p) var_LocationParse(VLC_OBJECT(o), m, p)

/**
 * @}
 */
#endif /*  _VLC_VARIABLES_H */