jack2/common/shm.h

#ifndef __jack_shm_h__
#define __jack_shm_h__

#include <limits.h>
#include <sys/types.h>
#include "types.h"
#include "JackCompilerDeps.h"


#define TRUE 1
#define FALSE 0

#ifdef __cplusplus
extern "C"
{
#endif

#define MAX_SERVERS 8			/* maximum concurrent servers */
#define MAX_SHM_ID 256			/* generally about 16 per server */
#define JACK_SERVER_NAME_SIZE 256	/* maximum length of server name */
#define JACK_SHM_MAGIC 0x4a41434b	/* shm magic number: "JACK" */
#define JACK_SHM_NULL_INDEX -1		/* NULL SHM index */
#define JACK_SHM_REGISTRY_INDEX -2	/* pseudo SHM index for registry */


    /* On Mac OS X, SHM_NAME_MAX is the maximum length of a shared memory
     * segment name (instead of NAME_MAX or PATH_MAX as defined by the
     * standard).
     */
#ifdef USE_POSIX_SHM

#ifndef SHM_NAME_MAX
#define SHM_NAME_MAX NAME_MAX
#endif
    typedef char	shm_name_t[SHM_NAME_MAX];
    typedef shm_name_t jack_shm_id_t;

#elif WIN32   // steph TO CHECK
#define NAME_MAX            255
#ifndef SHM_NAME_MAX
#define SHM_NAME_MAX NAME_MAX
#endif
    typedef char	shm_name_t[SHM_NAME_MAX];
    typedef shm_name_t jack_shm_id_t;

#else
    /* System V SHM */
    typedef int	jack_shm_id_t;
#endif /* SHM type */

    /* shared memory type */
    typedef enum {
        shm_POSIX = 1, 			/* POSIX shared memory */
        shm_SYSV = 2, 			/* System V shared memory */
        shm_WIN32 = 3			/* Windows 32 shared memory */
    } jack_shmtype_t;

    typedef int16_t jack_shm_registry_index_t;

    /**
     * A structure holding information about shared memory allocated by
     * JACK. this persists across invocations of JACK, and can be used by
     * multiple JACK servers.  It contains no pointers and is valid across
     * address spaces.
     *
     * The registry consists of two parts: a header including an array of
     * server names, followed by an array of segment registry entries.
     */
    typedef struct _jack_shm_server {
#ifdef WIN32
        int	pid;	/* process ID */
#else

        pid_t pid;	/* process ID */
#endif

        char	name[JACK_SERVER_NAME_SIZE];
    }
    jack_shm_server_t;

    typedef struct _jack_shm_header {
        uint32_t	magic;	/* magic number */
        uint16_t	protocol;	/* JACK protocol version */
        jack_shmtype_t	type;	/* shm type */
        jack_shmsize_t	size;	/* total registry segment size */
        jack_shmsize_t	hdr_len;	/* size of header */
        jack_shmsize_t	entry_len; /* size of registry entry */
        jack_shm_server_t server[MAX_SERVERS]; /* current server array */
    }
    jack_shm_header_t;

    typedef struct _jack_shm_registry {
        jack_shm_registry_index_t index;     /* offset into the registry */

#ifdef WIN32

        int	allocator; /* PID that created shm segment */
#else

        pid_t allocator; /* PID that created shm segment */
#endif

        jack_shmsize_t size;      /* for POSIX unattach */
        jack_shm_id_t id;        /* API specific, see above */
    }
    jack_shm_registry_t;

#define JACK_SHM_REGISTRY_SIZE (sizeof (jack_shm_header_t) \
				+ sizeof (jack_shm_registry_t) * MAX_SHM_ID)

    /**
     * a structure holding information about shared memory
     * allocated by JACK. this version is valid only
     * for a given address space. It contains a pointer
     * indicating where the shared memory has been
     * attached to the address space.
     */
    typedef struct _jack_shm_info {
        jack_shm_registry_index_t index;       /* offset into the registry */
        size_t size;
        void *attached_at; /* address where attached */
    }
    jack_shm_info_t;

    /* utility functions used only within JACK */
      
    void jack_shm_copy_from_registry (jack_shm_info_t*,
                jack_shm_registry_index_t);
    void jack_shm_copy_to_registry (jack_shm_info_t*,
                                               jack_shm_registry_index_t*);
    void jack_release_shm_info (jack_shm_registry_index_t);
    char* jack_shm_addr (jack_shm_info_t* si);  // steph

    // here begin the API 
    int jack_register_server (const char *server_name, int new_registry);
    void jack_unregister_server (const char *server_name);

    int jack_initialize_shm (const char *server_name);
    int jack_initialize_shm_server (void);  // steph
    int jack_initialize_shm_client (void);  // steph
    int jack_cleanup_shm (void);

    int jack_shmalloc (const char *shm_name, jack_shmsize_t size,
                                  jack_shm_info_t* result);
    void jack_release_shm (jack_shm_info_t*);
    void jack_destroy_shm (jack_shm_info_t*);
    int jack_attach_shm (jack_shm_info_t*);
    int jack_attach_shm_read (jack_shm_info_t*); // steph
    int jack_resize_shm (jack_shm_info_t*, jack_shmsize_t size);

#ifdef __cplusplus
}
#endif

#endif /* __jack_shm_h__ */