* Licensed under the GPL v2. For licencing details see COPYING.
*/
-/** \file filter.h filter-related structures and exported symbols from filter_chain.c */
+/** \file filter.h Filter-related structures and exported symbols from filter_chain.c. */
-/**
- * describes one running instance of a chain of filters
- *
- */
+/** Describes one running instance of a chain of filters */
struct filter_chain {
/**
+ * The number of channels of the current stream.
*
- *
- * the number of channels of the current stream
- *
- * Set by the decoding filter
+ * Set by the decoding filter.
*/
- unsigned int channels;
+ unsigned int channels;
/**
+ * Current sample rate in Hz.
*
- *
- * current samplerate in Hz
- *
- * Set by the decoding filter
+ * Set by the decoding filter.
*/
- unsigned int samplerate;
+ unsigned int samplerate;
+ /** The list containing all filter nodes in this filter chain. */
+ struct list_head filters;
/**
- *
- *
- * the list containing all filter nodes in this filter chain
- */
- struct list_head filters;
- /**
- *
- *
- * the input buffer of the filter chain
+ * 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 *inbuf;
- /**
- *
- *
- * the output buffer of the filter chain
- *
- * Points to the output buffer of the last filter in the filter chain
- **/
- char *outbuf;
- /**
- *
- *
- * pointer to variable containing the number of bytes loaded in the input buffer
+ * current receiver for para_audiod).
*/
- size_t *in_loaded;
+ char *inbuf;
/**
+ * The output buffer of the filter chain.
*
- *
- * pointer to variable containing the number of bytes loaded in the output buffer
+ * Points to the output buffer of the last filter in the filter chain.
*/
- size_t *out_loaded;
+ char *outbuf;
+ /** 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;
/** Non-zero if this filter wont' produce any more output. */
int error;
/** Pointer to the error variable of the receiving application. */
int *input_error;
- /** Pointer to the eof flag of the writing application. */
+ /** Pointer to the error variable of the writing application. */
int *output_error;
- /** the task associated with the filter chain */
+ /** The task associated with the filter chain. */
struct task task;
};
/**
- * describes one running instance of a filter
+ * Describes one running instance of a filter.
*/
struct filter_node {
-/**
- *
- *
- * a pointer to the corresponding filter struct
- */
+ /** A pointer to the corresponding filter struct. */
struct filter *filter;
-/**
- *
- *
- * the filter chain this filter node belongs to
- */
+ /** The filter chain this filter node belongs to. */
struct filter_chain *fc;
-/**
- *
- *
- * the position of the filter in the corresponding filter chain
- *
- * all filters that make up the filter chains are organized in a doubly
- * linked list.
- */
+ /**
+ * The position of the filter in the corresponding filter chain.
+ *
+ * All filters that make up the filter chains are organized in a doubly
+ * linked list.
+ */
struct list_head node;
-/**
- *
- *
- * each filter may store any filter-specific information about the particular
- * instance of the filter here.
- */
+ /**
+ * Each filter may store any filter-specific information about the particular
+ * instance of the filter here.
+ */
void *private_data;
-/**
- *
- *
- * the output buffer
- */
+ /** The output buffer. */
char *buf;
-/**
- * the size of the output buffer
- */
+ /** The size of the output buffer. */
size_t bufsize;
-/**
- *
- *
- * the number of bytes currently loaded in \a buf
- */
+ /** The number of bytes currently loaded in \a buf. */
size_t loaded;
-/**
- *
- *
- * the list of registered callbacks
- */
+ /** The list of registered callbacks. */
struct list_head callbacks;
-/**
- *
- * a pointer to the configuration of this instance
- */
+ /** A pointer to the configuration of this instance. */
void *conf;
};
/**
- * used to manage grab clients
+ * 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
* the grab command.
*/
struct filter_callback {
-/**
- *
- *
- * all callbacks are organized in a doubly linked list
- */
+ /** All callbacks are organized in a doubly linked list. */
struct list_head node;
-/**
- *
- *
- * private data
- *
- * May be initialized by the application before registering the callback. This
- * pointer is not used by the filter subsystem. It is provided for use within
- * the input/ouput/close callback functions.
- */
+ /**
+ * Private data.
+ *
+ * May be initialized by the application before registering the callback. This
+ * pointer is not used by the filter subsystem. It is provided for use within
+ * the input/output/close callback functions.
+ */
void *data;
-/**
- *
- *
- * the input callback
- *
- * In 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.
- */
+ /**
+ * The input callback.
+ *
+ * In 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.
- */
+ /**
+ * 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/ouput callback returned an error, or if
- * the filter chain is going to be destroyed, e.g. because the end of the
- * stream was encounterd. It is assumed to succeed.
- */
+ /**
+ * 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);
};
void filter_pre_select(__a_unused struct sched *s, struct task *t);
/**
- * the structure associated with a paraslash filter
+ * 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
* \sa mp3dec.c, oggdec.c, wav.c, compress.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 \a f.
- */
-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.
- */
-void (*open)(struct filter_node *fn);
-/**
- *
- *
- * convert (filter) the given data
- *
- * Pointer to the converting function of the filter. It should convert the
- * given input buffer \a inbuf which is of length \a len to the previoulsy
- * reserved output buffer of \a fn. On success, it must return the number of
- * bytes it consumed from \a inbuf. On errors, a negative number indicating the
- * kind of the error must be returned.
- *
- * A zero return value just means that nothing was converted (probably because
- * the input buffer was too small). This is not interpreted as an error.
- */
-ssize_t (*convert)(char *inbuf, size_t len, 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.
- */
-void (*close)(struct filter_node *fn);
-/**
- *
- *
- * print the help text for this filter and exit
- *
- * This is optional and it is not necessary to initialize this pointer if
- * the filter does not have a help text.
- */
-void (*print_help)(void);
-/**
- *
- *
- * a pointer to the filter's command line parser
- *
- * If this optional function pointer is not NULL, any filter options are passed
- * from the main propgram 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. On success, it should return a
- * pointer to the filter-specific configuration data determined by \a argc and
- * \a argv.
- */
-void *(*parse_config)(int argc, char **argv);
+ /** 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.
+ */
+ void (*open)(struct filter_node *fn);
+ /**
+ * Convert (filter) the given data.
+ *
+ * Pointer to the converting function of the filter. It should convert the
+ * given input buffer \a inbuf which is of length \a len to the previously
+ * reserved output buffer of \a fn. On success, it must return the number of
+ * bytes it consumed from \a inbuf. On errors, a negative number indicating the
+ * kind of the error must be returned.
+ *
+ * A zero return value just means that nothing was converted (probably because
+ * the input buffer was too small). This is not interpreted as an error.
+ */
+ ssize_t (*convert)(char *inbuf, size_t len, 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.
+ */
+ void (*close)(struct filter_node *fn);
+ /**
+ * Print the help text for this filter and exit.
+ *
+ * This is optional and it is not necessary to initialize this pointer if
+ * the filter does not have a help text.
+ */
+ void (*print_help)(void);
+ /**
+ * A pointer to the filter's command line parser.
+ *
+ * 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. On success, it should return a
+ * pointer to the filter-specific configuration data determined by \a argc and
+ * \a argv.
+ */
+ void *(*parse_config)(int argc, char **argv);
};
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