/*

 * 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 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),

 *     AV_OPT_TYPE_BINARY },

 *   { NULL },

 * };

 *

 * static const AVClass test_class = {

 *     .class_name = "test class",

 *     .item_name  = av_default_item_name,

 *     .option     = options,

 *     .version    = LIBAVUTIL_VERSION_INT,

 * };

 * @endcode

 *

 * Next, when allocating your struct, you must ensure that the AVClass pointer

 * is set to the correct value. Then, av_opt_set_defaults() must be called to

 * initialize defaults. After that the struct is ready to be used with the

 * AVOptions API.

 *

 * When cleaning up, you may use the av_opt_free() function to automatically

 * free all the allocated string and binary options.

 *

 * Continuing with the above example:

 *

 * @code

 * test_struct *alloc_test_struct(void)

 * {

 *     test_struct *ret = av_malloc(sizeof(*ret));

 *     ret->class = &test_class;

 *     av_opt_set_defaults(ret);

 *     return ret;

 * }

 * void free_test_struct(test_struct **foo)

 * {

 *     av_opt_free(*foo);

 *     av_freep(foo);

 * }

 * @endcode

 *

 * @subsection avoptions_implement_nesting Nesting

 *      It may happen that an AVOptions-enabled struct contains another

 *      AVOptions-enabled struct as a member (e.g. AVCodecContext in

 *      libavcodec exports generic options, while its priv_data field exports

 *      codec-specific options). In such a case, it is possible to set up the

 *      parent struct to export a child's options. To do that, simply

 *      implement AVClass.child_next() and AVClass.child_class_next() in the

 *      parent struct's AVClass.

 *      Assuming that the test_struct from above now also contains a

 *      child_struct field:

 *

 *      @code

 *      typedef struct child_struct {

 *          AVClass *class;

 *          int flags_opt;

 *      } child_struct;

 *      static const AVOption child_opts[] = {

 *          { "test_flags", "This is a test option of flags type.",

 *            offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX },

 *          { NULL },

 *      };

 *      static const AVClass child_class = {

 *          .class_name = "child class",

 *          .item_name  = av_default_item_name,

 *          .option     = child_opts,

 *          .version    = LIBAVUTIL_VERSION_INT,

 *      };

 *

 *      void *child_next(void *obj, void *prev)

 *      {

 *          test_struct *t = obj;

 *          if (!prev && t->child_struct)

 *              return t->child_struct;

 *          return NULL

 *      }

 *      const AVClass child_class_next(const AVClass *prev)

 *      {

 *          return prev ? NULL : &child_class;

 *      }

 *      @endcode

 *      Putting child_next() and child_class_next() as defined above into

 *      test_class will now make child_struct's options accessible through

 *      test_struct (again, proper setup as described above needs to be done on

 *      child_struct right after it is created).

 *

 *      From the above example it might not be clear why both child_next()

 *      and child_class_next() are needed. The distinction is that child_next()

 *      iterates over actually existing objects, while child_class_next()

 *      iterates over all possible child classes. E.g. if an AVCodecContext

 *      was initialized to use a codec which has private options, then its

 *      child_next() will return AVCodecContext.priv_data and finish

 *      iterating. OTOH child_class_next() on AVCodecContext.av_class will

 *      iterate over all available codecs with private options.

 *

 * @subsection avoptions_implement_named_constants Named constants

 *      It is possible to create named constants for options. Simply set the unit

 *      field of the option the constants should apply to to a string and

 *      create the constants themselves as options of type AV_OPT_TYPE_CONST

 *      with their unit field set to the same string.

 *      Their default_val field should contain the value of the named

 *      constant.

 *      For example, to add some named constants for the test_flags option

 *      above, put the following into the child_opts array:

 *      @code

 *      { "test_flags", "This is a test option of flags type.",

 *        offsetof(child_struct, flags_opt), AV_OPT_TYPE_FLAGS, { .i64 = 0 }, INT_MIN, INT_MAX, "test_unit" },

 *      { "flag1", "This is a flag with value 16", 0, AV_OPT_TYPE_CONST, { .i64 = 16 }, 0, 0, "test_unit" },

 *      @endcode

 *

 * @section avoptions_use Using AVOptions

 * This section deals with accessing options in an AVOptions-enabled struct.

 * Such structs in Libav are e.g. AVCodecContext in libavcodec or

 * AVFormatContext in libavformat.

 *

 * @subsection avoptions_use_examine Examining AVOptions

 * The basic functions for examining options are av_opt_next(), which iterates

 * over all options defined for one object, and av_opt_find(), which searches

 * for an option with the given name.

 *

 * The situation is more complicated with nesting. An AVOptions-enabled struct

 * may have AVOptions-enabled children. Passing the AV_OPT_SEARCH_CHILDREN flag

 * to av_opt_find() will make the function search children recursively.

 *

 * For enumerating there are basically two cases. The first is when you want to

 * get all options that may potentially exist on the struct and its children

 * (e.g.  when constructing documentation). In that case you should call

 * av_opt_child_class_next() recursively on the parent struct's AVClass.  The

 * second case is when you have an already initialized struct with all its

 * children and you want to get all options that can be actually written or read

 * from it. In that case you should call av_opt_child_next() recursively (and

 * av_opt_next() on each result).

 *

 * @subsection avoptions_use_get_set Reading and writing AVOptions

 * When setting options, you often have a string read directly from the

 * user. In such a case, simply passing it to av_opt_set() is enough. For

 * non-string type options, av_opt_set() will parse the string according to the

 * option type.

 *

 * Similarly av_opt_get() will read any option type and convert it to a string

 * which will be returned. Do not forget that the string is allocated, so you

 * have to free it with av_free().

 *

 * In some cases it may be more convenient to put all options into an

 * AVDictionary and call av_opt_set_dict() on it. A specific case of this

 * are the format/codec open functions in lavf/lavc which take a dictionary

 * filled with option as a parameter. This allows to set some options

 * that cannot be set otherwise, since e.g. the input file format is not known

 * before the file is actually opened.

 */

enum AVOptionType{

    AV_OPT_TYPE_FLAGS,

    AV_OPT_TYPE_INT,

    AV_OPT_TYPE_INT64,

    AV_OPT_TYPE_DOUBLE,

    AV_OPT_TYPE_FLOAT,

    AV_OPT_TYPE_STRING,

    AV_OPT_TYPE_RATIONAL,

    AV_OPT_TYPE_BINARY,  ///< offset must point to a pointer immediately followed by an int for the length

    AV_OPT_TYPE_CONST = 128,

#if FF_API_OLD_AVOPTIONS

    FF_OPT_TYPE_FLAGS = 0,

    FF_OPT_TYPE_INT,

    FF_OPT_TYPE_INT64,

    FF_OPT_TYPE_DOUBLE,

    FF_OPT_TYPE_FLOAT,

    FF_OPT_TYPE_STRING,

    FF_OPT_TYPE_RATIONAL,

    FF_OPT_TYPE_BINARY,  ///< offset must point to a pointer immediately followed by an int for the length

    FF_OPT_TYPE_CONST=128,

#endif

};

/**

 * AVOption

 */

typedef struct AVOption {

    const char *name;

    /**

     * short English help text

     * @todo What about other languages?

     */

    const char *help;

    /**

     * The offset relative to the context structure where the option

     * value is stored. It should be 0 for named constants.

     */

    int offset;

    enum AVOptionType type;

    /**

     * the default value for scalar options

     */

    union {

        int64_t i64;

        double dbl;

        const char *str;

        /* TODO those are unused now */

        AVRational q;

    } default_val;

    double min;                 ///< minimum valid value for the option

    double max;                 ///< maximum valid value for the option

    int flags;

#define AV_OPT_FLAG_ENCODING_PARAM  1   ///< a generic parameter which can be set by the user for muxing or encoding

#define AV_OPT_FLAG_DECODING_PARAM  2   ///< a generic parameter which can be set by the user for demuxing or decoding

#define AV_OPT_FLAG_METADATA        4   ///< some data extracted or inserted into the file like title, comment, ...

#define AV_OPT_FLAG_AUDIO_PARAM     8

#define AV_OPT_FLAG_VIDEO_PARAM     16

#define AV_OPT_FLAG_SUBTITLE_PARAM  32

//FIXME think about enc-audio, ... style flags

    /**

     * The logical unit to which the option belongs. Non-constant

     * options and corresponding named constants share the same

     * unit. May be NULL.

     */

    const char *unit;

} AVOption;

#if FF_API_FIND_OPT

/**

 * Look for an option in obj. Look only for the options which

 * have the flags set as specified in mask and flags (that is,

 * for which it is the case that opt->flags & mask == flags).

 *

 * @param[in] obj a pointer to a struct whose first element is a

 * pointer to an AVClass

 * @param[in] name the name of the option to look for

 * @param[in] unit the unit of the option to look for, or any if NULL

 * @return a pointer to the option found, or NULL if no option

 * has been found

 *

 * @deprecated use av_opt_find.

 */

attribute_deprecated

const AVOption *av_find_opt(void *obj, const char *name, const char *unit, int mask, int flags);

#endif

#if FF_API_OLD_AVOPTIONS

/**

 * Set the field of obj with the given name to value.

 *

 * @param[in] obj A struct whose first element is a pointer to an

 * AVClass.

 * @param[in] name the name of the field to set

 * @param[in] val The value to set. If the field is not of a string

 * type, then the given string is parsed.

 * SI postfixes and some named scalars are supported.

 * If the field is of a numeric type, it has to be a numeric or named

 * scalar. Behavior with more than one scalar and +- infix operators

 * is undefined.

 * If the field is of a flags type, it has to be a sequence of numeric

 * scalars or named flags separated by '+' or '-'. Prefixing a flag

 * with '+' causes it to be set without affecting the other flags;

 * similarly, '-' unsets a flag.

 * @param[out] o_out if non-NULL put here a pointer to the AVOption

 * found

 * @param alloc this parameter is currently ignored

 * @return 0 if the value has been set, or an AVERROR code in case of

 * error:

 * AVERROR_OPTION_NOT_FOUND if no matching option exists

 * AVERROR(ERANGE) if the value is out of range

 * AVERROR(EINVAL) if the value is not valid

 * @deprecated use av_opt_set()

 */

attribute_deprecated

int av_set_string3(void *obj, const char *name, const char *val, int alloc, const AVOption **o_out);

attribute_deprecated const AVOption *av_set_double(void *obj, const char *name, double n);

attribute_deprecated const AVOption *av_set_q(void *obj, const char *name, AVRational n);

attribute_deprecated const AVOption *av_set_int(void *obj, const char *name, int64_t n);

attribute_deprecated double av_get_double(void *obj, const char *name, const AVOption **o_out);

attribute_deprecated AVRational av_get_q(void *obj, const char *name, const AVOption **o_out);

attribute_deprecated int64_t av_get_int(void *obj, const char *name, const AVOption **o_out);

attribute_deprecated const char *av_get_string(void *obj, const char *name, const AVOption **o_out, char *buf, int buf_len);

attribute_deprecated const AVOption *av_next_option(void *obj, const AVOption *last);

#endif

/**

 * Show the obj options.

 *

 * @param req_flags requested flags for the options to show. Show only the

 * options for which it is opt->flags & req_flags.

 * @param rej_flags rejected flags for the options to show. Show only the

 * options for which it is !(opt->flags & req_flags).

 * @param av_log_obj log context to use for showing the options

 */

int av_opt_show2(void *obj, void *av_log_obj, int req_flags, int rej_flags);

/**

 * Set the values of all AVOption fields to their default values.

 *

 * @param s an AVOption-enabled struct (its first member must be a pointer to AVClass)

 */

void av_opt_set_defaults(void *s);

#if FF_API_OLD_AVOPTIONS

attribute_deprecated

void av_opt_set_defaults2(void *s, int mask, int flags);

#endif

/**

 * Parse the key/value pairs list in opts. For each key/value pair

 * found, stores the value in the field in ctx that is named like the

 * key. ctx must be an AVClass context, storing is done using

 * AVOptions.

 *

 * @param key_val_sep a 0-terminated list of characters used to

 * separate key from value

 * @param pairs_sep a 0-terminated list of characters used to separate

 * two pairs from each other

 * @return the number of successfully set key/value pairs, or a negative

 * value corresponding to an AVERROR code in case of error:

 * AVERROR(EINVAL) if opts cannot be parsed,

 * the error code issued by av_set_string3() if a key/value pair

 * cannot be set

 */

int av_set_options_string(void *ctx, const char *opts,

                          const char *key_val_sep, const char *pairs_sep);

/**

 * Free all string and binary options in obj.

 */

void av_opt_free(void *obj);

/**

 * Check whether a particular flag is set in a flags field.

 *

 * @param field_name the name of the flag field option

 * @param flag_name the name of the flag to check

 * @return non-zero if the flag is set, zero if the flag isn't set,

 *         isn't of the right type, or the flags field doesn't exist.

 */

int av_opt_flag_is_set(void *obj, const char *field_name, const char *flag_name);

/*

 * Set all the options from a given dictionary on an object.

 *

 * @param obj a struct whose first element is a pointer to AVClass

 * @param options options to process. This dictionary will be freed and replaced

 *                by a new one containing all options not found in obj.

 *                Of course this new dictionary needs to be freed by caller

 *                with av_dict_free().

 *

 * @return 0 on success, a negative AVERROR if some option was found in obj,

 *         but could not be set.

 *

 * @see av_dict_copy()

 */

int av_opt_set_dict(void *obj, struct AVDictionary **options);

/**

 * @defgroup opt_eval_funcs Evaluating option strings

 * @{

 * This group of functions can be used to evaluate option strings

 * and get numbers out of them. They do the same thing as av_opt_set(),

 * except the result is written into the caller-supplied pointer.

 *

 * @param obj a struct whose first element is a pointer to AVClass.

 * @param o an option for which the string is to be evaluated.

 * @param val string to be evaluated.

 * @param *_out value of the string will be written here.

 *

 * @return 0 on success, a negative number on failure.

 */

int av_opt_eval_flags (void *obj, const AVOption *o, const char *val, int        *flags_out);

int av_opt_eval_int   (void *obj, const AVOption *o, const char *val, int        *int_out);

int av_opt_eval_int64 (void *obj, const AVOption *o, const char *val, int64_t    *int64_out);

int av_opt_eval_float (void *obj, const AVOption *o, const char *val, float      *float_out);

int av_opt_eval_double(void *obj, const AVOption *o, const char *val, double     *double_out);

int av_opt_eval_q     (void *obj, const AVOption *o, const char *val, AVRational *q_out);

/**

 * @}

 */

#define AV_OPT_SEARCH_CHILDREN   0x0001 /**< Search in possible children of the

                                             given object first. */

/**

 *  The obj passed to av_opt_find() is fake -- only a double pointer to AVClass

 *  instead of a required pointer to a struct containing AVClass. This is

 *  useful for searching for options without needing to allocate the corresponding

 *  object.

 */

#define AV_OPT_SEARCH_FAKE_OBJ   0x0002

/**

 * Look for an option in an object. Consider only options which

 * have all the specified flags set.

 *

 * @param[in] obj A pointer to a struct whose first element is a

 *                pointer to an AVClass.

 *                Alternatively a double pointer to an AVClass, if

 *                AV_OPT_SEARCH_FAKE_OBJ search flag is set.

 * @param[in] name The name of the option to look for.

 * @param[in] unit When searching for named constants, name of the unit

 *                 it belongs to.

 * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).

 * @param search_flags A combination of AV_OPT_SEARCH_*.

 *

 * @return A pointer to the option found, or NULL if no option

 *         was found.

 *

 * @note Options found with AV_OPT_SEARCH_CHILDREN flag may not be settable

 * directly with av_set_string3(). Use special calls which take an options

 * AVDictionary (e.g. avformat_open_input()) to set options found with this

 * flag.

 */

const AVOption *av_opt_find(void *obj, const char *name, const char *unit,

                            int opt_flags, int search_flags);

/**

 * Look for an option in an object. Consider only options which

 * have all the specified flags set.

 *

 * @param[in] obj A pointer to a struct whose first element is a

 *                pointer to an AVClass.

 *                Alternatively a double pointer to an AVClass, if

 *                AV_OPT_SEARCH_FAKE_OBJ search flag is set.

 * @param[in] name The name of the option to look for.

 * @param[in] unit When searching for named constants, name of the unit

 *                 it belongs to.

 * @param opt_flags Find only options with all the specified flags set (AV_OPT_FLAG).

 * @param search_flags A combination of AV_OPT_SEARCH_*.

 * @param[out] target_obj if non-NULL, an object to which the option belongs will be

 * written here. It may be different from obj if AV_OPT_SEARCH_CHILDREN is present

 * in search_flags. This parameter is ignored if search_flags contain

 * AV_OPT_SEARCH_FAKE_OBJ.

 *

 * @return A pointer to the option found, or NULL if no option

 *         was found.

 */

const AVOption *av_opt_find2(void *obj, const char *name, const char *unit,

                             int opt_flags, int search_flags, void **target_obj);

/**

 * Iterate over all AVOptions belonging to obj.

 *

 * @param obj an AVOptions-enabled struct or a double pointer to an

 *            AVClass describing it.

 * @param prev result of the previous call to av_opt_next() on this object

 *             or NULL

 * @return next AVOption or NULL

 */

const AVOption *av_opt_next(void *obj, const AVOption *prev);

/**

 * Iterate over AVOptions-enabled children of obj.

 *

 * @param prev result of a previous call to this function or NULL

 * @return next AVOptions-enabled child or NULL

 */

void *av_opt_child_next(void *obj, void *prev);

/**

 * Iterate over potential AVOptions-enabled children of parent.

 *

 * @param prev result of a previous call to this function or NULL

 * @return AVClass corresponding to next potential child or NULL