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midimonster.h
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midimonster.h
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#ifndef MIDIMONSTER_HEADER
#define MIDIMONSTER_HEADER
#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#define max(a,b) (((a) > (b)) ? (a) : (b))
#ifdef DEBUG
#define DBGPF(format, ...) fprintf(stderr, (format), __VA_ARGS__)
#define DBG(message) fprintf(stderr, "%s", (message))
#else
#define DBGPF(format, ...)
#define DBG(message)
#endif
#define DEFAULT_CFG "monster.cfg"
struct _channel_value;
struct _backend_channel;
struct _backend_instance;
struct _managed_fd;
/*
* Backend module callback defines
*
* The lifecycle of a backend module is as follows
* * int init()
* The only function that should be exported by the shared object.
* Called when the shared object is attached. Should register
* a backend structure with the core.
* Returning anything other than zero causes midimonster to fail the
* startup checks.
* * mmbackend_configure
* Parse backend-global configuration options from the user-supplied
* configuration file. Returning a non-zero value fails config parsing.
* * mmbackend_instance
* Allocate space for a backend instance. Returning NULL signals an out-of-memory
* condition and terminates the program.
* * mmbackend_configure_instance
* Parse instance configuration from the user-supplied configuration
* file. Returning a non-zero value fails config parsing.
* * mmbackend_channel
* Parse a channel-spec to be mapped to/from. Returning NULL signals an
* out-of-memory condition and terminates the program.
* * mmbackend_start
* Called after all instances have been created and all mappings
* have been set up. May be used to connect to backing hardware
* or to update runtime-specific data in the various data structures.
* Returning a non-zero value signals an error starting the backend
* and stops further progress.
* * Normal processing loop starts here
* * mmbackend_process_fd
* Handle data from signaled fds registered via mm_manage_fd.
* Push generated events to the core with mm_channel_event.
* All registered fds that are ready to read are pushed at once.
* Backends that have not registered any fds are still called with
* nfds set to 0 in order to support polling backends.
* Returning a non-zero value signals an error and gracefully terminates
* the program.
* * mmbackend_handle_event
* An event resulted in a channel for an instance being set.
* Called once per changed instance with all updated channels for that
* specific instance.
* Returning a non-zero value terminates the program.
* * (optional) mmbackend_interval
* Return the maximum sleep interval for this backend in milliseconds.
* If not implemented, a maximum interval of one second is used.
* * mmbackend_shutdown
* Clean up all allocations, finalize all hardware connections.
* Return value is currently ignored.
*/
typedef int (*mmbackend_handle_event)(struct _backend_instance* inst, size_t channels, struct _backend_channel** c, struct _channel_value* v);
typedef struct _backend_instance* (*mmbackend_create_instance)();
typedef struct _backend_channel* (*mmbackend_parse_channel)(struct _backend_instance* instance, char* spec);
typedef void (*mmbackend_free_channel)(struct _backend_channel* c);
typedef int (*mmbackend_configure)(char* option, char* value);
typedef int (*mmbackend_configure_instance)(struct _backend_instance* instance, char* option, char* value);
typedef int (*mmbackend_process_fd)(size_t nfds, struct _managed_fd* fds);
typedef int (*mmbackend_start)();
typedef uint32_t (*mmbackend_interval)();
typedef int (*mmbackend_shutdown)();
typedef struct _channel_value {
union {
double dbl;
uint64_t u64;
} raw;
double normalised;
} channel_value;
typedef struct /*_mm_backend*/ {
char* name;
mmbackend_configure conf;
mmbackend_create_instance create;
mmbackend_configure_instance conf_instance;
mmbackend_parse_channel channel;
mmbackend_handle_event handle;
mmbackend_process_fd process;
mmbackend_start start;
mmbackend_shutdown shutdown;
mmbackend_free_channel channel_free;
mmbackend_interval interval;
} backend;
typedef struct _backend_instance {
backend* backend;
uint64_t ident;
void* impl;
char* name;
} instance;
typedef struct _backend_channel {
instance* instance;
uint64_t ident;
void* impl;
} channel;
//FIXME might be replaced by struct pollfd
//FIXME who frees impl
typedef struct _managed_fd {
int fd;
backend* backend;
void* impl;
} managed_fd;
typedef struct /*_mm_channel_mapping*/ {
channel* from;
size_t destinations;
channel** to;
} channel_mapping;
/*
* Register a new backend.
*/
int mm_backend_register(backend b);
/*
* Provides a pointer to a newly (zero-)allocated instance.
* All instance pointers need to be allocated via this API
* in order to be assignable from the configuration parser.
* This API should be called from the mmbackend_create_instance
* call of your backend.
*
* Instances returned from this call are freed by midimonster.
* The contents of the impl members should be freed in the
* mmbackend_shutdown procedure of the backend, eg. by querying
* all instances for the backend.
*/
instance* mm_instance();
/*
* Finds an instance matching the specified backend and identifier.
* Since setting an identifier for an instance is optional,
* this may not work depending on the backend.
* Instance identifiers may for example be set in the backends
* mmbackend_start call.
*/
instance* mm_instance_find(char* backend, uint64_t ident);
/*
* Provides a pointer to a channel structure, pre-filled with
* the provided instance reference and identifier.
* The `create` parameter is a boolean flag indicating whether
* a channel matching the `ident` parameter should be created if
* none exists. If the instance already registered a channel
* matching `ident`, a pointer to it is returned.
* This API is just a convenience function. The array of channels is
* only used for mapping internally, creating and managing your own
* channel store is possible.
* For each channel with a non-NULL `impl` field registered using
* this function, the backend will receive a call to its channel_free
* function.
*/
channel* mm_channel(instance* i, uint64_t ident, uint8_t create);
//TODO channel* mm_channel_find()
/*
* Register a file descriptor to be selected on. The backend
* will be notified via the mmbackend_process_fd call.
* This function may only be called from within the mmbackend_start
* procedure.
*/
int mm_manage_fd(int fd, char* backend, int manage, void* impl);
/*
* Notifies the core of a channel event. Used by backends to
* inject events gathered from their backing implementation.
*/
int mm_channel_event(channel* c, channel_value v);
/*
* Query all active instances for a given backend.
* *i will need to be freed by the caller.
*/
int mm_backend_instances(char* backend, size_t* n, instance*** i);
int mm_map_channel(channel* from, channel* to);
#endif