mailbox.h

#ifndef BIO_MAILBOX_H
#define BIO_MAILBOX_H
 
#include <bio/bio.h>
 
#ifndef DOXYGEN
 
#if __STDC_VERSION__ >= 202311L
#   define BIO__TYPEOF(EXP) typeof(EXP)
#elif defined(__clang__) || defined(__GNUC__) || defined(_MSC_VER)
#   define BIO__TYPEOF(EXP) __typeof__(EXP)
#endif
 
#ifdef BIO__TYPEOF
// _Static_assert is actually quite hard to use in an expression.
// Jamming it into a struct: `sizeof(struct{_Static_assert(...);})` doesn't work
// quite well.
// Clang requires the RHS of BIO__TYPECHECK_EXP to be a constant expression
// which is not always the case in typical user code.
// The good old negative size array works in all compilers but the error message
// is somewhat cryptic.
#   define BIO__TYPECHECK_EXP(LHS, RHS) \
    (void)sizeof(char[_Generic(RHS, BIO__TYPEOF(LHS): 1, default: -1)]) /* If you get an error here, you have the wrong type */
#else
// Check both size and assignability as integer types of different sizes are
// assignable (with warnings).
// We can't count on user having warnings enabled.
#   define BIO__TYPECHECK_EXP(LHS, RHS) \
    ((void)sizeof(LHS = RHS), (void)sizeof(char[sizeof(LHS) == sizeof(RHS) ? 1 : -1]))  /* If you get an error here, you have the wrong type */
#endif
 
#endif
 
#define BIO_MAILBOX(T) union { bio_handle_t bio__handle; T* bio__message; }
 
#define bio_open_mailbox(ptr, capacity) \
    bio__mailbox_open(&(ptr)->bio__handle, sizeof(*(ptr)->bio__message), capacity)
 
#define bio_close_mailbox(mailbox) \
    bio__mailbox_close((mailbox).bio__handle)
 
#define bio_is_mailbox_open(mailbox) \
    bio__mailbox_is_open((mailbox).bio__handle)
 
#define bio_send_message(mailbox, message) \
    ( \
        BIO__TYPECHECK_EXP(message, *mailbox.bio__message), \
        bio__mailbox_send(mailbox.bio__handle, &message, sizeof(message)) \
    )
 
#define bio_wait_and_send_message(condition, mailbox, message) \
    do { \
        while ((bio_is_mailbox_open(mailbox)) && (condition)) { \
            if (bio_send_message((mailbox), (message))) { break; } \
            bio_yield(); \
        } \
    } while (0)
 
#define bio_recv_message(mailbox, message) \
    ( \
        BIO__TYPECHECK_EXP(*(message), *(mailbox.bio__message)), \
        bio__mailbox_recv(mailbox.bio__handle, (message), sizeof(*(message))) \
    )
 
#define bio_can_recv_message(mailbox) \
    bio__mailbox_can_recv((mailbox).bio__handle)
 
#define bio_can_send_message(mailbox) \
    bio__mailbox_can_send((mailbox).bio__handle)
 
#define bio_foreach_message(msg, mailbox) \
    for ( \
        BIO__TYPEOF(*(mailbox).bio__message) msg; \
        bio_recv_message(mailbox, &msg); \
    )
 
#ifndef DOXYGEN
 
void
bio__mailbox_open(bio_handle_t* handle, size_t item_size, uint32_t capacity);
 
void
bio__mailbox_close(bio_handle_t handle);
 
bool
bio__mailbox_is_open(bio_handle_t handle);
 
bool
bio__mailbox_send(bio_handle_t handle, const void* data, size_t message_size);
 
bool
bio__mailbox_recv(bio_handle_t handle, void* data, size_t message_size);
 
bool
bio__mailbox_can_recv(bio_handle_t handle);
 
bool
bio__mailbox_can_send(bio_handle_t handle);
 
#endif
 
#endif