// NewReader create new initialized table reader.
func NewReader(r storage.Reader, size uint64, o opt.OptionsGetter, cache cache.Namespace) (p *Reader, err error) {
mb, ib, err := readFooter(r, size)
if err != nil {
return
}
t := &Reader{r: r, o: o, dataEnd: mb.offset, cache: cache}
// index block
buf, err := ib.readAll(r, true)
if err != nil {
return
}
t.indexBlock, err = block.NewReader(buf, o.GetComparer())
if err != nil {
return
}
// we will ignore any errors at meta/filter block
// since it is not essential for operation
// meta block
buf, err1 := mb.readAll(r, true)
if err1 != nil {
return
}
meta, err1 := block.NewReader(buf, comparer.BytesComparer{})
if err1 != nil {
return
}
// filter block
iter := meta.NewIterator()
for iter.Next() {
key := string(iter.Key())
if !strings.HasPrefix(key, "filter.") {
continue
}
if filter := o.GetAltFilter(key[7:]); filter != nil {
fb := new(bInfo)
_, err1 = fb.decodeFrom(iter.Value())
if err1 != nil {
continue
}
// now the data block end before filter block start offset
// instead of meta block start offset
t.dataEnd = fb.offset
buf, err1 = fb.readAll(r, true)
if err1 != nil {
continue
}
t.filterBlock, err1 = block.NewFilterReader(buf, filter)
if err1 != nil {
continue
}
break
}
}
return t, nil
}
// NewReader create new initialized table reader.
func NewReader(r desc.Reader, size uint64, o opt.OptionsGetter, cache cache.Namespace) (p *Reader, err error) {
mb, ib, err := readFooter(r, size)
if err != nil {
return
}
t := &Reader{r: r, o: o, dataEnd: mb.offset, cache: cache}
// index block
buf, err := ib.readAll(r, true)
if err != nil {
return
}
t.index, err = block.NewReader(buf, o.GetComparer())
if err != nil {
return
}
// filter block
filter := o.GetFilter()
if filter != nil {
// we will ignore any errors at meta/filter block
// since it is not essential for operation
// meta block
buf, err = mb.readAll(r, true)
if err != nil {
goto out
}
var meta *block.Reader
meta, err = block.NewReader(buf, comparer.BytesComparer{})
if err != nil {
goto out
}
// check for filter name
iter := meta.NewIterator()
key := "filter." + filter.Name()
if iter.Seek([]byte(key)) && string(iter.Key()) == key {
fb := new(bInfo)
_, err = fb.decodeFrom(iter.Value())
if err != nil {
return
}
// now the data end before filter block start offset
t.dataEnd = fb.offset
// filter block
buf, err = fb.readAll(r, true)
if err != nil {
goto out
}
t.filter, err = block.NewFilterReader(buf, filter)
if err != nil {
goto out
}
}
}
out:
return t, nil
}