/** \file write.h writer-related structures */
+/** the list of supported writers */
enum writer_enum {WRITER_ENUM};
+/**
+ * decbribes one running instance of a writer
+ */
struct writer_node {
+ /** points to the writer structure associated with this node */
struct writer *writer;
+ /** writer-specific data */
void *private_data;
+ /** send that many bytes in one go */
int chunk_bytes;
+ struct task task;
+ struct writer_node_group *wng;
+ /** the writer-specific configuration of this node */
+ void *conf;
};
+/** describes one supported writer */
struct writer {
- void (*init)(struct writer *w);
- int (*open)(struct writer_node *);
- int (*write)(char *data, size_t nbytes, struct writer_node *);
- void (*close)(struct writer_node *);
- void (*shutdown)(struct writer_node *);
+/**
+ * the init function of the writer
+ *
+ * It must fill in all other function pointers of the given
+ * writer structure.
+ *
+ */
+void (*init)(struct writer *w);
+/**
+ *
+ *
+ * the command line parser of the writer
+ *
+ * It should check whether the command line options given by \a options are
+ * valid. On success, it should return a pointer to the writer-specific
+ * configuration data determined by \a options. Note that this might be called
+ * more than once with different values of \a options.
+ *
+ */
+ void * (*parse_config)(char *options);
+/**
+ *
+ * open one instance of this writer
+ *
+ * This function should perform any work necessary to write the incoming
+ * stream. If To this aim, it may allocate its private data structure and store
+ * a pointer to that structure via the given writer_node paramenter.
+ */
+int (*open)(struct writer_node *);
+/**
+ *
+ * write a chunk of audio data
+ *
+ * This is called from the driving application whenever a data block of \a
+ * chunk_bytes is available. It must return the number of bytes consumed from
+ * \a data on success, and negative on errors.
+ *
+ */
+int (*write)(char *data, size_t nbytes, struct writer_node *);
+void (*pre_select)(struct sched *s, struct task *t);
+void (*post_select)(struct sched *s, struct task *t);
+/**
+ * close one instance of the writer
+ *
+ * This function is assumed to succeed.
+ */
+void (*close)(struct writer_node *);
+/**
+ * shutdown the writer
+ *
+ * This is a optional function pointer used for cleaning
+ * up.
+ */
+void (*shutdown)(struct writer_node *);
};
+/**
+ * describes a set of writer nodes that all write the same stream.
+ */
struct writer_node_group {
+ /** number of nodes belonging to this group */
unsigned num_writers;
+ /** array of pointers to the corresponding writer nodes */
struct writer_node *writer_nodes;
+ /** keeps track of how many bytes have been written by each node */
int *written;
+ /** the maximum of the chunk_bytes values of the writer nodes in this group */
size_t max_chunk_bytes;
+ /** non-zero if end of file was encountered */
+ int *input_eof;
int eof;
+ char *buf;
+ unsigned int *channels;
+ unsigned int *samplerate;
+ size_t *loaded;
+ struct task task;
};
+/** loop over each writer node in a writer group */
#define FOR_EACH_WRITER_NODE(i, wng) for (i = 0; i < (wng)->num_writers; i++)
+/** loop over each supported writer */
#define FOR_EACH_WRITER(i) for (i = 0; i < NUM_SUPPORTED_WRITERS; i++)
+/** declare the init functions of all supported writers */
DECLARE_WRITER_INITS;
+
+/** array containing the name of each writer */
extern const char *writer_names[];
+
+/** the writer structure for each supported writer */
extern struct writer writers[NUM_SUPPORTED_WRITERS];