示例#1
0
func ReadAt(fd int, off int64, size int) ([]byte, error) {
	idx := <-idle_event
	retch := aio_result_map[idx]
	defer func() { idle_event <- idx }()

	var cb *C.struct_iocb = &cbs[idx]

	var read_buf unsafe.Pointer
	C.posix_memalign(&read_buf, pagesize, C.size_t(size))
	defer C.free(read_buf)

	C.io_prep_pread(cb, C.int(fd), read_buf, C.size_t(size), C.longlong(off))
	cbs[idx].data = unsafe.Pointer(&idx)

	aio_lock.Lock()
	rt := C.io_submit(ctx, 1, &cb)
	if int(rt) < 0 {
		aio_lock.Unlock()
		return nil, errors.New("io submit failed")
	}
	aiocount++
	aio_lock.Unlock()

	select {
	case have_aio_event <- 0:
	default:
	}

	ret := <-retch

	return ret.buf, ret.err
}
示例#2
0
// The function allocates size bytes. The address of the allocated memory will
// be a multiple of alignment, which must be a power of two and a multiple of
// sizeof(void *). Alignment or size must not be 0 or the method will
// intentionally panic.
func NewAlignedBuffer(alignment int64, size int) (AlignedBuffer, error) {
	if alignment == 0 || size == 0 {
		panic(error(syscall.EINVAL))
	}

	// Allocate memory
	var ptr unsafe.Pointer
	pbuff := &ptr
	rv := C.posix_memalign(pbuff, (C.size_t)(alignment), (C.size_t)(size))
	if rv < 0 {
		err := (syscall.Errno)(rv)
		return nil, err
	}

	// Create a slice on top of allocated memory
	return &_AlignedBuffer{uintptr(ptr), size}, nil
}
示例#3
0
func WriteAt(fd int, off int64, buf []byte) (int, error) {
	size := len(buf)
	if size == 0 {
		return 0, nil
	}

	idx := <-idle_event
	retch := aio_result_map[idx]
	defer func() { idle_event <- idx }()

	var cb *C.struct_iocb = &cbs[idx]

	var write_buf unsafe.Pointer
	C.posix_memalign(&write_buf, pagesize, C.size_t(size))
	defer C.free(write_buf)
	for i := 0; i < size; i++ {
		*(*byte)(unsafe.Pointer(uintptr(write_buf) + uintptr(i))) = buf[i]
	}

	C.io_prep_pwrite(cb, C.int(fd), write_buf, C.size_t(size), C.longlong(off))
	cbs[idx].data = unsafe.Pointer(&idx)

	aio_lock.Lock()
	rt := C.io_submit(ctx, 1, &cb)

	if int(rt) < 0 {
		aio_lock.Unlock()
		return 0, errors.New("io submit failed")
	}
	aiocount++
	aio_lock.Unlock()

	select {
	case have_aio_event <- 0:
	default:
	}

	ret := <-retch
	return ret.size, ret.err
}
func posixMemalign(alignment uint64, size uint64) []byte {
	var ptr C.void
	ptr2 := unsafe.Pointer(&ptr)
	writesize := C.posix_memalign(&ptr2, C.size_t(uintptr(alignment)), C.size_t(uintptr(size)))
	return []byte(C.GoBytes(unsafe.Pointer(&ptr), writesize))
}