#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{
- FF_OPT_TYPE_FLAGS,
- 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,
+ 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,
};
/**
* the default value for scalar options
*/
union {
+ int64_t i64;
double dbl;
const char *str;
/* TODO those are unused now */
- int64_t i64;
AVRational q;
} default_val;
double min; ///< minimum valid value for the option
const char *unit;
} AVOption;
-/**
- * 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
- */
-const AVOption *av_find_opt(void *obj, const char *name, const char *unit, int mask, int flags);
-
-/**
- * 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 when 1 then the old value will be av_freed() and the
- * new av_strduped()
- * when 0 then no av_free() nor av_strdup() will be used
- * @return 0 if the value has been set, or an AVERROR code in case of
- * error:
- * AVERROR(ENOENT) if no matching option exists
- * AVERROR(ERANGE) if the value is out of range
- * AVERROR(EINVAL) if the value is not valid
- */
-int av_set_string3(void *obj, const char *name, const char *val, int alloc, const AVOption **o_out);
-
-const AVOption *av_set_double(void *obj, const char *name, double n);
-const AVOption *av_set_q(void *obj, const char *name, AVRational n);
-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);
-const char *av_get_string(void *obj, const char *name, const AVOption **o_out, char *buf, int buf_len);
-const AVOption *av_next_option(void *obj, const AVOption *last);
-
/**
* Show the obj 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);
-void av_opt_set_defaults2(void *s, int mask, int flags);
/**
* Parse the key/value pairs list in opts. For each key/value pair
*/
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
+ */
+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);
+/**
+ * @}
+ */
+
+/**
+ * @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);
+/**
+ * @}
+ * @}
+ */
+
#endif /* AVUTIL_OPT_H */
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