opt.h

/*
 * AVOptions
 * copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
 *
 * This file is part of Libav.
 *
 * Libav 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.
 *
 * Libav 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 Libav; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#ifndef AVUTIL_OPT_H
#define AVUTIL_OPT_H

/**
 * @file
 * AVOptions
 */

#include "rational.h"
#include "avutil.h"
#include "dict.h"
#include "log.h"

/**
 * @defgroup avoptions AVOptions
 * @ingroup lavu_data
 * @{
 * AVOptions provide a generic system to declare options on arbitrary structs
 * ("objects"). An option can have a help text, a type and a range of possible
 * values. Options may then be enumerated, read and written to.
 *
 * @section avoptions_implement Implementing AVOptions
 * This section describes how to add AVOptions capabilities to a struct.
 *
 * All AVOptions-related information is stored in an AVClass. Therefore
 * the first member of the struct must be a pointer to an AVClass describing it.
 * The option field of the AVClass must be set to a NULL-terminated static array
 * of AVOptions. Each AVOption must have a non-empty name, a type, a default
 * value and for number-type AVOptions also a range of allowed values. It must
 * also declare an offset in bytes from the start of the struct, where the field
 * associated with this AVOption is located. Other fields in the AVOption struct
 * should also be set when applicable, but are not required.
 *
 * The following example illustrates an AVOptions-enabled struct:
 * @code
 * typedef struct test_struct {
 *     AVClass *class;
 *     int      int_opt;
 *     char    *str_opt;
 *     uint8_t *bin_opt;
 *     int      bin_len;
 * } test_struct;
 *
 * static const AVOption test_options[] = {
 *   { "test_int", "This is a test option of int type.", offsetof(test_struct, int_opt),
 *     AV_OPT_TYPE_INT, { .i64 = -1 }, INT_MIN, INT_MAX },
 *   { "test_str", "This is a test option of string type.", offsetof(test_struct, str_opt),
 *     AV_OPT_TYPE_STRING },
 *   { "test_bin", "This is a test option of binary type.", offsetof(test_struct, bin_opt),