int rb_write_to_buffer(ring_buffer *buffer, int n, ...) {
if (!buffer) return -1;
int write_idx = buffer->write_idx; // No need for sync in writer thread.
int available = rb_available_to_write(buffer);
va_list args;
va_start(args, n);
int i;
for (i = 0; i < n; ++i) {
const char* src = va_arg(args, const char*);
int len = va_arg(args, int);
available -= len;
if (len < 0 || available < 0) return -1;
if (write_idx + len <= buffer->size) {
memcpy(buffer->buf_ptr + write_idx, src, len);
} else {
int d = buffer->size - write_idx;
memcpy(buffer->buf_ptr + write_idx, src, d);
memcpy(buffer->buf_ptr, src + d, len - d);
}
write_idx = (write_idx + len) % buffer->size;
}
va_end(args);
SYNC_COMPARE_AND_SWAP(&(buffer->write_idx), buffer->write_idx,
write_idx); // Includes memory barrier.
return 0;
}
int rb_read_from_buffer(ring_buffer *buffer, char *dest, int len) {
if (len == 0) return 0;
if (!buffer || len < 0 || len > rb_available_to_read(buffer)) return -1;
// Note that rb_available_to_read also serves as a memory barrier, and so any
// writes to buffer->buf_ptr that precede the update of buffer->write_idx are
// visible to us now.
int read_idx = buffer->read_idx; // No need for sync in reader thread.
if (read_idx + len <= buffer->size) {
memcpy(dest, buffer->buf_ptr + read_idx, len);
} else {
int d = buffer->size - read_idx;
memcpy(dest, buffer->buf_ptr + read_idx, d);
memcpy(dest + d, buffer->buf_ptr, len - d);
}
SYNC_COMPARE_AND_SWAP(&(buffer->read_idx), buffer->read_idx,
(read_idx + len) % buffer->size); // Includes memory barrier.
return 0;
}
U_CAPI void U_EXPORT2
umtx_init(UMTX *mutex) {
ICUMutex *m = NULL;
void *originalValue;
if (*mutex != NULL) {
/* Mutex is already initialized.
* Multiple umtx_init()s of a UMTX by other ICU code are explicitly permitted.
*/
return;
}
#if defined(POSIX)
if (mutex == &globalUMTX) {
m = &globalMutex;
}
#endif
m = umtx_ct(m);
originalValue = SYNC_COMPARE_AND_SWAP(mutex, NULL, m);
if (originalValue != NULL) {
umtx_dt(m);
return;
}
m->owner = mutex;
/* Hook the new mutex into the list of all ICU mutexes, so that we can find and
* delete it for u_cleanup().
*/
umtx_lock(NULL);
m->next = mutexListHead;
mutexListHead = m;
umtx_unlock(NULL);
return;
}
