Backend Interface

Data Structures
struct	rte_context
struct	rte_context_class
struct	rte_backend_class
Defines
#define	RTE_OPTION_BOUNDS_INITIALIZER_(type_, def_, min_, max_, step_) { type_ = def_ }, { type_ = min_ }, { type_ = max_ }, { type_ = step_ }
#define	RTE_OPTION_BOOL_INITIALIZER(key_, label_, def_, tip_)
#define	RTE_OPTION_INT_RANGE_INITIALIZER(key_, label_, def_, min_, max_, step_, tip_)
#define	RTE_OPTION_INT_MENU_INITIALIZER(key_, label_, def_,menu_, entries_, tip_)
#define	RTE_OPTION_REAL_RANGE_INITIALIZER(key_, label_, def_, min_, max_, step_, tip_)
#define	RTE_OPTION_REAL_MENU_INITIALIZER(key_, label_, def_,menu_, entries_, tip_)
#define	RTE_OPTION_STRING_INITIALIZER(key_, label_, def_, tip_)
#define	RTE_OPTION_STRING_MENU_INITIALIZER(key_, label_, def_,menu_, entries_, tip_)
#define	RTE_OPTION_MENU_INITIALIZER(key_, label_, def_, menu_,entries_, tip_)
#define	RTE_OPTION_ARG(type, min, max)
#define	RTE_OPTION_ARG_MENU(menu) RTE_OPTION_ARG(int, 0, sizeof(menu) / sizeof(menu[0]))
#define	RTE_OPTION_ARG_SAT(type, min, max)
#define	RTE_2(x) #x
#define	RTE_1(x) RTE_2(x)
#define	nullcheck(X, whattodo)
Typedefs
typedef struct rte_context_class	rte_context_class
typedef struct rte_backend_class	rte_backend_class
Enumerations
enum	rte_state { RTE_STATE_NEW = 0, RTE_STATE_PARAM, RTE_STATE_READY, RTE_STATE_RUNNING, RTE_STATE_PAUSED }
enum	rte_io_method { RTE_CALLBACK_MASTER = 1, RTE_CALLBACK_SLAVE, RTE_PUSH_MASTER, RTE_PUSH_SLAVE, RTE_FIFO, RTE_FILE, RTE_STDIO, RTE_DISCARD }
Functions
void	rte_unknown_option (rte_context context, rte_codec codec, const char *keyword)
void	rte_invalid_option (rte_context context, rte_codec codec, const char *keyword,...)
void	rte_asprintf (char *errstr, const char templ,...)
char *	rte_strdup (rte_context context, char d, const char s)
unsigned int	rte_closest_int (const int *vec, unsigned int len, int val)
unsigned int	rte_closest_double (const double *vec, unsigned int len, double val)
rte_bool	rte_option_string (rte_context context, rte_codec codec, const char *optstr)
static_inline int	rte_closest_int_val (const int *vec, unsigned int len, int val)
static_inline double	rte_closest_double_val (const double *vec, unsigned int len, double val)
static_inline void	rte_error_reset (rte_context *context)

Detailed Description

These, together with the public RTE structures, are the definitions of the RTE backend interface from rtepriv.h. Only backends use this, not RTE clients.

Define Documentation

#define RTE_OPTION_BOOL_INITIALIZER	(	key_,
		label_,
		def_,
		tip_	)

Value:

{ RTE_OPTION_BOOL, key_, label_, RTE_OPTION_BOUNDS_INITIALIZER_(        \
  .num, def_, 0, 1, 1), { .num = NULL }, tip_ }

Helper macro for backends to build option lists. Use like this:

 rte_option_info myinfo = RTE_OPTION_BOOL_INITIALIZER
   ("mute", N_("Switch sound on/off"), FALSE, N_("I am a tooltip"));

N_() marks the string for i18n, see info gettext for details.

#define RTE_OPTION_INT_RANGE_INITIALIZER	(	key_,
		label_,
		def_,
		min_,
		max_,
		step_,
		tip_	)

Value:

{ RTE_OPTION_INT, key_, label_,                 \
  RTE_OPTION_BOUNDS_INITIALIZER_(.num, def_, min_, max_, step_),        \
  { .num = NULL }, tip_ }

Helper macro for backends to build option lists. Use like this:

 rte_option_info myinfo = RTE_OPTION_INT_RANGE_INITIALIZER
   ("sampling", N_("Sampling rate"), 44100, 8000, 48000, 100, NULL);

Here we have no tooltip (NULL).

#define RTE_OPTION_INT_MENU_INITIALIZER	(	key_,
		label_,
		def_,
		menu_,
		entries_,
		tip_	)

Value:

{ RTE_OPTION_INT, key_, label_,         \
  RTE_OPTION_BOUNDS_INITIALIZER_(.num, def_, 0, (entries_) - 1, 1),     \
  { .num = menu_ }, tip_ }

Helper macro for backends to build option lists. Use like this:

 int mymenu[] = { 29, 30, 31 };

 rte_option_info myinfo = RTE_OPTION_INT_MENU_INITIALIZER
   ("days", NULL, 1, mymenu, 3, NULL);

No label and tooltip (NULL), i. e. this option is not to be listed in the user interface. Default is entry 1 ("30") of 3 entries.

#define RTE_OPTION_REAL_RANGE_INITIALIZER	(	key_,
		label_,
		def_,
		min_,
		max_,
		step_,
		tip_	)

Value:

{ RTE_OPTION_REAL, key_, label_,                        \
  RTE_OPTION_BOUNDS_INITIALIZER_(.dbl, def_, min_, max_, step_),        \
  { .dbl = NULL }, tip_ }

Helper macro for backends to build option lists. Use like RTE_OPTION_INT_RANGE_INITIALIZER(), just with doubles but ints.

#define RTE_OPTION_REAL_MENU_INITIALIZER	(	key_,
		label_,
		def_,
		menu_,
		entries_,
		tip_	)

Value:

{ RTE_OPTION_REAL, key_, label_,                \
  RTE_OPTION_BOUNDS_INITIALIZER_(.num, def_, 0, (entries_) - 1, 1),     \
  { .dbl = menu_ }, tip_ }

Helper macro for backends to build option lists. Use like RTE_OPTION_INT_MENU_INITIALIZER(), just with an array of doubles but ints.

#define RTE_OPTION_STRING_INITIALIZER	(	key_,
		label_,
		def_,
		tip_	)

Value:

{ RTE_OPTION_STRING, key_, label_, RTE_OPTION_BOUNDS_INITIALIZER_(      \
  .str, def_, NULL, NULL, NULL), { .str = NULL }, tip_ }

Helper macro for backends to build option lists. Use like this:

 rte_option_info myinfo = RTE_OPTION_STRING_INITIALIZER
   ("comment", N_("Comment"), "bububaba", "Please enter a string");

#define RTE_OPTION_STRING_MENU_INITIALIZER	(	key_,
		label_,
		def_,
		menu_,
		entries_,
		tip_	)

Value:

{ RTE_OPTION_STRING, key_, label_,              \
  RTE_OPTION_BOUNDS_INITIALIZER_(.str, def_, 0, (entries_) - 1, 1),     \
  { .str = menu_ }, tip_ }

Helper macro for backends to build option lists. Use like this:

 char *mymenu[] = { "txt", "html" };

 rte_option_info myinfo = RTE_OPTION_STRING_MENU_INITIALIZER
   ("extension", "Ext", 0, mymenu, 2, N_("Select an extension"));

Remember this is like RTE_OPTION_STRING_INITIALIZER() in the sense that the rte client can pass any string as option value, not just those proposed in the menu. In contrast a plain menu option as with RTE_OPTION_MENU_INITIALIZER() expects menu indices as input.

#define RTE_OPTION_MENU_INITIALIZER	(	key_,
		label_,
		def_,
		menu_,
		entries_,
		tip_	)

Value:

{ RTE_OPTION_MENU, key_, label_,                        \
  RTE_OPTION_BOUNDS_INITIALIZER_(.num, def_, 0, (entries_) - 1, 1),     \
  { .str = menu_ }, tip_ }

Helper macro for backends to build option lists. Use like this:

 char *mymenu[] = { N_("Monday"), N_("Tuesday") };

 rte_option_info myinfo = RTE_OPTION_MENU_INITIALIZER
   ("weekday", "Weekday, 0, mymenu, 2, N_("Select a weekday"));

#define RTE_OPTION_ARG	(	type,
		min,
		max	)

Value:

({                                                                      \
        type val = va_arg(args, type);                                  \
                                                                        \
        if (val < (min) || val > (max)) {                               \
                rte_invalid_option(context, codec, keyword, val);       \
                goto failed;                                            \
        }                                                               \
                val;                                                    \
})

Helper macro for backends to parse options. Use like this:

 myfunc (va_list args)
 {
   int myval = RTE_OPTION_ARG (int, -100, +200);

   :

   failed:
     return FALSE;
 }

#define RTE_OPTION_ARG_MENU ( menu ) RTE_OPTION_ARG(int, 0, sizeof(menu) / sizeof(menu[0]))

Helper macro for backends to parse options. Use like this:

 char *mymenu[] = { N_("Monday"), N_("Tuesday") };

 myfunc (va_list args)
 {
   int myval = RTE_OPTION_ARG_MENU (mymenu); // fails if not 0 ... 1

   :

   failed:
     return FALSE;
 }

#define RTE_OPTION_ARG_SAT	(	type,
		min,
		max	)

Value:

({                                                                      \
        type val = va_arg(args, type);                                  \
                                                                        \
        if (val < (min)) val = min;                                     \
        else if (val > (max)) val = max;                                \
        val;                                                            \
})

Helper macro for backends to parse options. Same as RTE_OPTION_ARG(), but saturates argument to min...max instead of failing.

#define nullcheck	(	X,
		whattodo		)

Value:

do {                                                                    \
        if ((X) == NULL) {                                              \
                const char *s = "rte:" __FILE__ ":" RTE_1(__LINE__)     \
                                ":%s: " #X " == NULL.\n";               \
                if (context)                                            \
                        rte_error_printf(context, s,                    \
                                         __PRETTY_FUNCTION__);          \
                else                                                    \
                        fprintf(stderr, s, __PRETTY_FUNCTION__);        \
                whattodo;                                               \
        }                                                               \
} while (0)

Typedef Documentation

typedef struct rte_context_class rte_context_class

Part of the backend interface.

Enumeration Type Documentation

enum rte_state

Context or codec state. The state field in rte_context and rte_codec must be set by the context and codec functions as documented below.

Enumerator:

RTE_STATE_NEW	Set on success of: codec_class->_new() codec_class->option_set() context_class->_new() context_class->option_set() context_class->stop()
RTE_STATE_PARAM	On success of: codec_class->parameters_set()
RTE_STATE_READY	On success of: codec_class->set_input() context_class->set_output()
RTE_STATE_RUNNING	On success of: context_class->start() (-> stop, -> pause)
RTE_STATE_PAUSED	On success of: context_class->pause() (-> start, -> stop)

enum rte_io_method

I/O mode.

Enumerator:

RTE_CALLBACK_MASTER	rte_set_input_callback_master()
RTE_CALLBACK_SLAVE	rte_set_input_callback_slave()
RTE_PUSH_MASTER	rte_set_input_push_master()
RTE_PUSH_SLAVE	rte_set_input_push_slave()
RTE_FIFO	To be defined
RTE_FILE	Used by frontend only
RTE_STDIO	Used by frontend only
RTE_DISCARD	Used by frontend only

Function Documentation

void rte_unknown_option	(	rte_context *	context,
		rte_codec *	codec,
		const char *	keyword
	)

Parameters:

	context	Initialized rte_context as returned by rte_context_new().
	codec	Pointer to rte_codec if this refers to a codec option, `NULL` if context option.
	keyword	Keyword of the option, can be `NULL` or "".

RTE internal helper function for backends.

Sets the context error string.

void rte_invalid_option	(	rte_context *	context,
		rte_codec *	codec,
		const char *	keyword,
			...
	)

Parameters:

	context	Initialized rte_context as returned by rte_context_new().
	codec	Pointer to rte_codec if this refers to a codec option, `NULL` if context option.
	keyword	Keyword of the option, can be `NULL` or "".
	...	If the option is known, the invalid data (int, double, char *).

RTE internal helper function for backends.

Sets the context error string.

void rte_asprintf	(	char **	errstr,
		const char *	templ,
			...
	)

Parameters:

	errstr	Place to store the allocated string or `NULL`.
	templ	See printf().
	...	See printf().

RTE internal helper function for backends.

Identical to GNU or BSD libc asprintf().

char* rte_strdup	(	rte_context *	context,
		char **	d,
		const char *	s
	)

Parameters:

	context	Initialized rte_context as returned by rte_context_new().
	d	If non-zero, store pointer to allocated string here. When d is non-zero, free(d) the old string first.
	s	String to be duplicated.

RTE internal helper function for backends.

Same as the libc strdup(), except for d argument and setting the context error string on failure.

Returns:: NULL on failure, pointer to malloc()ed string otherwise.

unsigned int rte_closest_int	(	const int *	vec,
		unsigned int	len,
		int	val
	)

Parameters:

	vec	Vector of int values.
	len	Length of the vector.
	val	Value to be compared.

RTE internal helper function for backends.

Find in a vector of int values the entry closest to val and return its index, 0 ... n.

Returns:: Index. Never fails.

unsigned int rte_closest_double	(	const double *	vec,
		unsigned int	len,
		double	val
	)

Parameters:

	vec	Vector of double values.
	len	Length of the vector.
	val	Value to be compared.

RTE internal helper function for backends.

Find in a vector of double values the entry closest to val and return its index, 0 ... n.

Returns:: Index. Never fails.

Backend Interface

Data Structures

Defines

Typedefs

Enumerations

Functions

Detailed Description

Define Documentation

Typedef Documentation

Enumeration Type Documentation

Function Documentation