func (kc *KCDB) Cas(key, oval, nval []byte) (err error) {
ckey := (*C.char)(unsafe.Pointer(&key[0]))
var coval, cnval *C.char
loval, lnval := len(oval), len(nval)
if loval > 0 {
coval = (*C.char)(unsafe.Pointer(&oval[0]))
}
if lnval > 0 {
cnval = (*C.char)(unsafe.Pointer(&nval[0]))
}
if C.kcdbcas(kc.db, ckey, C.size_t(len(key)), coval, C.size_t(loval), cnval, C.size_t(lnval)) == 0 {
err = kc.error()
}
return
}
// CompareAndSwap performs a compare-and-swap operation, receiving three
// parameters: key, old and new.
//
// If the value corresponding to key is equal to old, then it is set to new. If
// the operation fails, this method returns a non-nil error.
func (d *DB) CompareAndSwap(key, old, new string) error {
cKey := C.CString(key)
defer C.free(unsafe.Pointer(cKey))
lKey := C.size_t(len(key))
cOldValue := C.CString(old)
defer C.free(unsafe.Pointer(cOldValue))
lOldValue := C.size_t(len(old))
cNewValue := C.CString(new)
defer C.free(unsafe.Pointer(cNewValue))
lNewValue := C.size_t(len(new))
if C.kcdbcas(d.db, cKey, lKey, cOldValue, lOldValue, cNewValue, lNewValue) == 0 {
return d.LastError()
}
return nil
}