/*
- * Copyright (C) 2005-2009 Andre Noll <maan@systemlinux.org>
+ * Copyright (C) 2005 Andre Noll <maan@tuebingen.mpg.de>
*
* Licensed under the GPL v2. For licencing details see COPYING.
*/
/** \file filter.h Filter-related structures and exported symbols from filter_common.c. */
-/** The list of supported filters. */
-enum filter_enum {FILTER_ENUM};
-
/**
* Describes one running instance of a filter.
*/
struct filter_node {
/** The number in the array of available filters. */
unsigned filter_num;
- /** The filter chain this filter node belongs to. */
- struct filter_chain *fc;
/**
* Each filter may store any filter-specific information about the particular
* instance of the filter here.
*/
void *private_data;
- /** The output buffer. */
- char *buf;
- /** The size of the output buffer. */
- size_t bufsize;
- /** The number of bytes currently loaded in \a buf. */
- size_t loaded;
/** The list of registered callbacks. */
struct list_head callbacks;
/** A pointer to the configuration of this instance. */
void *conf;
+ /** The parsed command line, merged with options given in the config file. */
+ struct lls_parse_result *lpr;
+ /** The buffer tree node. */
struct btr_node *btrn;
- struct task task;
+ /** The task corresponding to this filter node. */
+ struct task *task;
+ /** The minimal input queue size, see \ref btr_node_status(). */
size_t min_iqs;
};
-/** Describes one running instance of a chain of filters */
-struct filter_chain {
- /** The length of the filter chain. */
- unsigned int num_filters;
- /**
- * The number of channels of the current stream.
- *
- * Set by the decoding filter.
- */
- unsigned int channels;
- /**
- * Current sample rate in Hz.
- *
- * Set by the decoding filter.
- */
- unsigned int samplerate;
- /** The list containing all filter nodes in this filter chain. */
- struct filter_node *filter_nodes;
- /**
- * The input buffer of the filter chain.
- *
- * This is set to point to the output buffer of the receiving application (the
- * buffer used to read from stdin for para_filter; the output buffer of the
- * current receiver for para_audiod).
- */
- char **inbufp;
- /**
- * The output buffer of the filter chain.
- *
- * Points to the output buffer of the last filter in the filter chain.
- */
- char **outbufp;
- /** Contains the number of bytes loaded in the input buffer. */
- size_t *in_loaded;
- /** Contains the number of bytes loaded in the output buffer. */
- size_t *out_loaded;
- /** Pointer to the error variable of the receiving application. */
- int *input_error;
- /** Pointer to the error variable of the writing application. */
- int *output_error;
- /** The task associated with the filter chain. */
- struct task task;
-};
-
-#define FOR_EACH_FILTER_NODE(fn, fc, i) for (i = 0; i < (fc)->num_filters \
- && (fn = (fc)->filter_nodes + i); i++)
-
-
-/**
- * Used to manage grab clients.
- *
- * An application using paraslash's filter subsystem may register any number of
- * callbacks for each filter_node. It is possible to attach a filter callback
- * while the filter is running. This is used for stream grabbing in
- * para_audiod: Whenever a client sends the 'grab' command, para_audiod adds a
- * filter callback to the list of callbacks for the filter node specified in
- * the grab command.
- */
-struct filter_callback {
- /** All callbacks are organized in a doubly linked list. */
- struct list_head node;
- /**
- * The input callback.
- *
- * If not \p NULL, the filter subsystem calls this function whenever the filter
- * consumed some or all of its input buffer. A pointer to the buffer of consumed
- * data, its length and a pointer to the own \a filter_callback structure are passed
- * to \a input_cb. The input callback is expected to return a negative value on errors.
- */
- int (*input_cb)(char *buf, size_t len, struct filter_callback *fc);
- /**
- * The output callback.
- *
- * If not NULL, this is called whenever the filter produces output. A pointer
- * to the output data, its length and a pointer to the own \a filter_callback
- * structure are passed to \a output_cb. Like the input callback, the output
- * callback is expected to return a negative value on errors.
- */
- int (*output_cb)(char *buf, size_t len, struct filter_callback *fc);
- /**
- * The callback close function.
- *
- * This gets called whenever the input/output callback returned an error, or if
- * the filter chain is going to be destroyed, e.g. because the end of the
- * stream was encountered. It is assumed to succeed.
- */
- void (*close)(struct filter_callback *fc);
-};
-
-
/**
* The structure associated with a paraslash filter.
*
- * Paraslash filters are "modules" which are used to transform an audio stream.
- * struct filter contains pointers to functions that must be supplied by the
- * filter code in order to be used by the driving application (currently
- * para_audiod and para_filter).
+ * Paraslash filters are "modules" which transform an audio stream. struct
+ * filter contains methods which are implemented by each filter.
*
* Note: As several instances of the same filter may be running at the same
* time, all these filter functions must be reentrant; no static non-constant
* variables may be used.
+ *
* \sa mp3dec_filter.c, oggdec_filter.c, wav_filter.c, compress_filter.c, filter_node
*/
struct filter {
- /** The name of the filter. */
- const char *name;
- /**
- * Pointer to the filter init routine.
- *
- * This function is only called once at startup. It must initialize the
- * other non-optional function pointers of this structure.
- */
- void (*init)(struct filter *f);
/**
* Open one instance of this filter.
*
- * This should allocate the output buffer of the given filter node and do any
- * other filter-specific preparations like initializing the private_data member
- * of \a fn suitably. The open function is assumed to succeed.
+ * This should allocate the output buffer of the given filter node and
+ * do any other filter-specific preparations like initializing the
+ * private_data member of \a fn suitably. The open function is
+ * optional, If it is provided, it is assumed to succeed.
*/
void (*open)(struct filter_node *fn);
/**
* Close one instance of this filter.
*
- * Free all resources of associated with \a fn that were previously allocated
- * by the open() function.
+ * Free all resources associated with \a fn that were previously
+ * allocated by the open() function. It's OK to set this to NULL if the
+ * filter does not need to perform any cleanup operation.
*/
void (*close)(struct filter_node *fn);
/**
- * A pointer to the filter's command line parser.
+ * Prepare the filter according to command line options.
*
- * If this optional function pointer is not NULL, any filter options
- * are passed from the main program to this command line parser once at
- * application startup. The command line parser should check its
- * command line options given by \a argc and \a argv and abort on
- * errors. Success must be indicated by a non-negative return value. In
- * this case the function should return a pointer to the
- * filter-specific configuration data determined by \a argc and \a
- * argv. On failure, a negative paraslash error code must be returned.
+ * In addition to the syntactic checks which are automatically performed
+ * by the lopsub functions, some filters like to also check the command
+ * line arguments semantically. Moreover, since applications may open
+ * the filter many times with the same options, filters need a method
+ * which allows them to precompute once those parts of the setup which
+ * depend only on the command line options.
+ *
+ * If this function pointer is not NULL, the function is called once at
+ * startup. The returned pointer value is made available to the ->open
+ * method via the ->conf pointer of struct filter_node.
+ *
+ * Filters are supposed to abort if the setup fails. If the function
+ * returns, it is assumed to have succeeded.
*/
- int (*parse_config)(int argc, char **argv, void **config);
- void (*free_config)(void *conf);
-
- /** The help texts for this filter. */
- struct ggo_help help;
- void (*pre_select)(struct sched *s, struct task *t);
+ void *(*setup)(const struct lls_parse_result *lpr);
+ /**
+ * Deallocate precomputed resources.
+ *
+ * This should free whatever ->setup() has allocated.
+ */
+ void (*teardown)(const struct lls_parse_result *lpr, void *conf);
+ /**
+ * Set scheduler timeout and add file descriptors to fd sets.
+ *
+ * This function controls the timeout value for the next call to
+ * select(2). It may decrease the current timeout but shall never
+ * increase it. The second purpose of this function is to add file
+ * descriptors to the two fd sets of the sched structure. The
+ * descriptors in these sets will be watched by the subsequent
+ * select(2) call.
+ */
+ void (*pre_select)(struct sched *s, void *context);
/**
* Convert (filter) the given data.
*
- * Pointer to the converting function of the filter. It should convert as
- * input data as possible. On errors, the post_select function is supposed
- * to set t->error to a (negative) error code.
+ * Pointer to the converting function of the filter. On errors, the
+ * post_select function is supposed to return a negative error code.
+ */
+ int (*post_select)(struct sched *s, void *context);
+ /**
+ * Answer a buffer tree query.
+ *
+ * This optional function pointer is used for inter node communications
+ * of the buffer tree nodes. See \ref btr_command_handler for details.
*/
- void (*post_select)(struct sched *s, struct task *t);
btr_command_handler execute;
};
-void close_filters(struct filter_chain *fc);
-void filter_init(void);
-int check_filter_arg(char *filter_arg, void **conf);
-void print_filter_helps(int detailed);
-void generic_filter_pre_select(struct sched *s, struct task *t);
+void print_filter_helps(bool detailed);
+int filter_setup(const char *fa, void **conf, struct lls_parse_result **lprp);
+#define FILTER_CMD(_num) (lls_cmd(_num, filter_cmd_suite))
+#define FILTER_CMD_OPT_RESULT(_cmd, _opt, _lpr) \
+ (lls_opt_result(LSG_FILTER_CMD_ ## _cmd ## _OPT_ ## _opt, _lpr))
+#define FILTER_CMD_OPT_GIVEN(_cmd, _opt, _lpr) \
+ (lls_opt_given(FILTER_CMD_OPT_RESULT(_cmd, _opt, _lpr)))
+#define FILTER_CMD_OPT_UINT32_VAL(_cmd, _opt, _lpr) \
+ (lls_uint32_val(0, FILTER_CMD_OPT_RESULT(_cmd, _opt, _lpr)))
+#define FILTER_CMD_OPT_STRING_VAL(_cmd, _opt, _lpr) \
+ (lls_string_val(0, FILTER_CMD_OPT_RESULT(_cmd, _opt, _lpr)))
+
+void generic_filter_pre_select(struct sched *s, void *context);
+int decoder_execute(const char *cmd, unsigned sample_rate, unsigned channels,
+ char **result);
static inline void write_int16_host_endian(char *buf, int val)
{
#endif
}
-DECLARE_FILTER_INITS
-
-#define FOR_EACH_SUPPORTED_FILTER(j) for (j = 0; j < NUM_SUPPORTED_FILTERS; j++)
-
-/** The filter array, one structure for each supported filter. */
-extern struct filter filters[NUM_SUPPORTED_FILTERS];
+/** Make a filter pointer from the filter number. */
+const struct filter *filter_get(int filter_num);
+const char *filter_name(int filter_num);
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