-/** 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);
-};
-
-