mm7: lib/libavutil/opt.h comparison

comparison lib/libavutil/opt.h @ 2134:992d2e6f907d

preparation for libavcodec

author	zipi
date	Tue, 31 Dec 2013 14:52:14 +0000
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-:e378232bfd36
+:992d2e6f907d
+/*
+* AVOptions
+* copyright (c) 2005 Michael Niedermayer <michaelni@gmx.at>
+*
+* This file is part of FFmpeg.
+*
+* FFmpeg 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.
+*
+* FFmpeg 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 FFmpeg; 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"
+#include "pixfmt.h"
+#include "samplefmt.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 should 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() can 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 FFmpeg 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,
+AV_OPT_TYPE_IMAGE_SIZE = MKBETAG('S','I','Z','E'), ///< offset must point to two consecutive integers
+AV_OPT_TYPE_PIXEL_FMT  = MKBETAG('P','F','M','T'),
+AV_OPT_TYPE_SAMPLE_FMT = MKBETAG('S','F','M','T'),
+AV_OPT_TYPE_VIDEO_RATE = MKBETAG('V','R','A','T'), ///< offset must point to AVRational
+AV_OPT_TYPE_DURATION   = MKBETAG('D','U','R',' '),
+AV_OPT_TYPE_COLOR      = MKBETAG('C','O','L','R'),
+#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
+#define AV_OPT_FLAG_FILTERING_PARAM (1<<16) ///< a generic parameter which can be set by the user for filtering
+//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;
+/**
+* A single allowed range of values, or a single allowed value.
+*/
+typedef struct AVOptionRange {
+const char *str;
+double value_min, value_max;             ///< For string ranges this represents the min/max length, for dimensions this represents the min/max pixel count
+double component_min, component_max;     ///< For string this represents the unicode range for chars, 0-127 limits to ASCII
+int is_range;                            ///< if set to 1 the struct encodes a range, if set to 0 a single value
+} AVOptionRange;
+/**
+* List of AVOptionRange structs
+*/
+typedef struct AVOptionRanges {
+AVOptionRange **range;
+int nb_ranges;
+} AVOptionRanges;
+#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);
+double av_get_double(void *obj, const char *name, const AVOption **o_out);
+AVRational av_get_q(void *obj, const char *name, const AVOption **o_out);
+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 opts options string to parse, may be NULL
+* @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);
+/**
+* Parse the key-value pairs list in opts. For each key=value pair found,
+* set the value of the corresponding option in ctx.
+*
+* @param ctx          the AVClass object to set options on
+* @param opts         the options string, key-value pairs separated by a
+*                     delimiter
+* @param shorthand    a NULL-terminated array of options names for shorthand
+*                     notation: if the first field in opts has no key part,
+*                     the key is taken from the first element of shorthand;
+*                     then again for the second, etc., until either opts is
+*                     finished, shorthand is finished or a named option is
+*                     found; after that, all options must be named
+* @param key_val_sep  a 0-terminated list of characters used to separate
+*                     key from value, for example '='
+* @param pairs_sep    a 0-terminated list of characters used to separate
+*                     two pairs from each other, for example ':' or ','
+* @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
+*
+* Options names must use only the following characters: a-z A-Z 0-9 - . / _
+* Separators must use characters distinct from option names and from each
+* other.
+*/
+int av_opt_set_from_string(void *ctx, const char *opts,
+const char *const *shorthand,
+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);
+/**
+* Extract a key-value pair from the beginning of a string.
+*
+* @param ropts        pointer to the options string, will be updated to
+*                     point to the rest of the string (one of the pairs_sep
+*                     or the final NUL)
+* @param key_val_sep  a 0-terminated list of characters used to separate
+*                     key from value, for example '='
+* @param pairs_sep    a 0-terminated list of characters used to separate
+*                     two pairs from each other, for example ':' or ','
+* @param flags        flags; see the AV_OPT_FLAG_* values below
+* @param rkey         parsed key; must be freed using av_free()
+* @param rval         parsed value; must be freed using av_free()
+*
+* @return  >=0 for success, or a negative value corresponding to an
+*          AVERROR code in case of error; in particular:
+*          AVERROR(EINVAL) if no key is present
+*
+*/
+int av_opt_get_key_value(const char **ropts,
+const char *key_val_sep, const char *pairs_sep,
+unsigned flags,
+char **rkey, char **rval);
+enum {
+/**
+* Accept to parse a value without a key; the key will then be returned
+* as NULL.
+*/
+AV_OPT_FLAG_IMPLICIT_KEY = 1,
+};
+/**
+* @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
+*/
+const AVClass *av_opt_child_class_next(const AVClass *parent, const AVClass *prev);
+/**
+* @defgroup opt_set_funcs Option setting functions
+* @{
+* Those functions 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. In case of av_opt_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 search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
+* is passed here, then the option may be set on a child of obj.
+*
+* @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
+*/
+int av_opt_set       (void *obj, const char *name, const char *val, int search_flags);
+int av_opt_set_int   (void *obj, const char *name, int64_t     val, int search_flags);
+int av_opt_set_double(void *obj, const char *name, double      val, int search_flags);
+int av_opt_set_q     (void *obj, const char *name, AVRational  val, int search_flags);
+int av_opt_set_bin   (void *obj, const char *name, const uint8_t *val, int size, int search_flags);
+int av_opt_set_image_size(void *obj, const char *name, int w, int h, int search_flags);
+int av_opt_set_pixel_fmt (void *obj, const char *name, enum AVPixelFormat fmt, int search_flags);
+int av_opt_set_sample_fmt(void *obj, const char *name, enum AVSampleFormat fmt, int search_flags);
+int av_opt_set_video_rate(void *obj, const char *name, AVRational val, int search_flags);
+/**
+* Set a binary option to an integer list.
+*
+* @param obj    AVClass object to set options on
+* @param name   name of the binary option
+* @param val    pointer to an integer list (must have the correct type with
+*               regard to the contents of the list)
+* @param term   list terminator (usually 0 or -1)
+* @param flags  search flags
+*/
+#define av_opt_set_int_list(obj, name, val, term, flags) \
+(av_int_list_length(val, term) > INT_MAX / sizeof(*(val)) ? \
+AVERROR(EINVAL) : \
+av_opt_set_bin(obj, name, (const uint8_t *)(val), \
+av_int_list_length(val, term) * sizeof(*(val)), flags))
+/**
+* @}
+*/
+/**
+* @defgroup opt_get_funcs Option getting functions
+* @{
+* Those functions get a value of the option with the given name from an object.
+*
+* @param[in] obj a struct whose first element is a pointer to an AVClass.
+* @param[in] name name of the option to get.
+* @param[in] search_flags flags passed to av_opt_find2. I.e. if AV_OPT_SEARCH_CHILDREN
+* is passed here, then the option may be found in a child of obj.
+* @param[out] out_val value of the option will be written here
+* @return 0 on success, a negative error code otherwise
+*/
+/**
+* @note the returned string will av_malloc()ed and must be av_free()ed by the caller
+*/
+int av_opt_get       (void *obj, const char *name, int search_flags, uint8_t   **out_val);
+int av_opt_get_int   (void *obj, const char *name, int search_flags, int64_t    *out_val);
+int av_opt_get_double(void *obj, const char *name, int search_flags, double     *out_val);
+int av_opt_get_q     (void *obj, const char *name, int search_flags, AVRational *out_val);
+int av_opt_get_image_size(void *obj, const char *name, int search_flags, int *w_out, int *h_out);
+int av_opt_get_pixel_fmt (void *obj, const char *name, int search_flags, enum AVPixelFormat *out_fmt);
+int av_opt_get_sample_fmt(void *obj, const char *name, int search_flags, enum AVSampleFormat *out_fmt);
+int av_opt_get_video_rate(void *obj, const char *name, int search_flags, AVRational *out_val);
+/**
+* @}
+*/
+/**
+* Gets a pointer to the requested field in a struct.
+* This function allows accessing a struct even when its fields are moved or
+* renamed since the application making the access has been compiled,
+*
+* @returns a pointer to the field, it can be cast to the correct type and read
+*          or written to.
+*/
+void *av_opt_ptr(const AVClass *avclass, void *obj, const char *name);
+/**
+* Free an AVOptionRanges struct and set it to NULL.
+*/
+void av_opt_freep_ranges(AVOptionRanges **ranges);
+/**
+* Get a list of allowed ranges for the given option.
+*
+* The returned list may depend on other fields in obj like for example profile.
+*
+* @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
+*              AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
+*
+* The result must be freed with av_opt_freep_ranges.
+*
+* @return >= 0 on success, a negative errro code otherwise
+*/
+int av_opt_query_ranges(AVOptionRanges **, void *obj, const char *key, int flags);
+/**
+* Get a default list of allowed ranges for the given option.
+*
+* This list is constructed without using the AVClass.query_ranges() callback
+* and can be used as fallback from within the callback.
+*
+* @param flags is a bitmask of flags, undefined flags should not be set and should be ignored
+*              AV_OPT_SEARCH_FAKE_OBJ indicates that the obj is a double pointer to a AVClass instead of a full instance
+*
+* The result must be freed with av_opt_free_ranges.
+*
+* @return >= 0 on success, a negative errro code otherwise
+*/
+int av_opt_query_ranges_default(AVOptionRanges **, void *obj, const char *key, int flags);
+/**
+* @}
+*/
+#endif /* AVUTIL_OPT_H */

Mercurial > mm7

comparison lib/libavutil/opt.h @ 2134:992d2e6f907d