// Create a new varchar structure. This takes a blockfile and an offset
// of an allocated block. The block becomes the control block for the
// varchar file (storing the free list for the allocator). It is
// important for the parent structure to track the location of this
// control block.
func NewVarchar(bf *fmap.BlockFile, a uint64) (v *Varchar, err error) {
ptOff, err := bf.Allocate()
if err != nil {
return nil, err
}
posTree, err := NewAt(bf, ptOff, 8, 0)
if err != nil {
return nil, err
}
szOff, err := bf.Allocate()
if err != nil {
return nil, err
}
sizeTree, err := NewAt(bf, szOff, 4, 8)
if err != nil {
return nil, err
}
v = &Varchar{
bf: bf,
posTree: posTree,
sizeTree: sizeTree,
a: a,
blkSize: bf.BlockSize(),
}
err = v.bf.Do(v.a, 1, func(bytes []byte) error {
ctrl := asCtrl(bytes)
ctrl.Init(ptOff, szOff)
return nil
})
if err != nil {
return nil, err
}
return v, nil
}
func NewAt(bf *fmap.BlockFile, ctrl_a uint64) (*List, error) {
vc_a, err := bf.Allocate()
if err != nil {
return nil, err
}
it_a, err := bf.Allocate()
if err != nil {
return nil, err
}
v, err := bptree.NewVarchar(bf, vc_a)
if err != nil {
return nil, err
}
it, err := bptree.NewAt(bf, it_a, 8, 8)
if err != nil {
return nil, err
}
l := &List{
bf: bf,
varchar: v,
idxTree: it,
a: ctrl_a,
count: 0,
}
err = l.bf.Do(ctrl_a, 1, func(bytes []byte) error {
c := l.asCtrl(bytes)
c.Init(vc_a, it_a)
return nil
})
if err != nil {
return nil, err
}
return l, nil
}
func New(bf *fmap.BlockFile) (*List, error) {
ctrl_a, err := bf.Allocate()
if err != nil {
return nil, err
}
data := make([]byte, 8)
moff := slice.AsUint64(&data)
*moff = ctrl_a
err = bf.SetControlData(data)
if err != nil {
return nil, err
}
return NewAt(bf, ctrl_a)
}
func (t *T) assert_alc(bf *fmap.BlockFile) uint64 {
a, err := bf.Allocate()
t.assert_nil(err)
return a
}
