object/store: Rename back from storer; rename Store to ReadingStore v0.1.118

1 files changed, 78 insertions, 0 deletions

diff --git a/object/store/packed/idx_parse.go b/object/store/packed/idx_parse.go
new file mode 100644
index 00000000..4da3bf42
--- /dev/null
+++ b/object/store/packed/idx_parse.go
@@ -0,0 +1,78 @@
+package packed
+
+import (
+	"encoding/binary"
+	"fmt"
+)
+
+const (
+	idxMagicV2   = 0xff744f63
+	idxVersionV2 = 2
+)
+
+// parse validates mapped idx v2 structure and stores table boundaries.
+func (index *idxFile) parse() error {
+	hashSize := index.algo.Size()
+	if hashSize <= 0 {
+		return fmt.Errorf("objectstore/packed: idx %q has invalid hash algorithm", index.idxName)
+	}
+
+	minLen := 8 + 256*4 + 2*hashSize
+	if len(index.data) < minLen {
+		return fmt.Errorf("objectstore/packed: idx %q too short", index.idxName)
+	}
+
+	if binary.BigEndian.Uint32(index.data[:4]) != idxMagicV2 {
+		return fmt.Errorf("objectstore/packed: idx %q invalid magic", index.idxName)
+	}
+
+	if binary.BigEndian.Uint32(index.data[4:8]) != idxVersionV2 {
+		return fmt.Errorf("objectstore/packed: idx %q unsupported version", index.idxName)
+	}
+
+	prev := uint32(0)
+
+	for i := range 256 {
+		base := 8 + i*4
+
+		cur := binary.BigEndian.Uint32(index.data[base : base+4])
+		if cur < prev {
+			return fmt.Errorf("objectstore/packed: idx %q has non-monotonic fanout table", index.idxName)
+		}
+
+		index.fanout[i] = cur
+		prev = cur
+	}
+
+	index.numObjects = int(index.fanout[255])
+	if index.numObjects < 0 {
+		return fmt.Errorf("objectstore/packed: idx %q has invalid object count", index.idxName)
+	}
+
+	namesBytes := index.numObjects * hashSize
+	crcBytes := index.numObjects * 4
+	offset32Bytes := index.numObjects * 4
+
+	minSize := 8 + 256*4 + namesBytes + crcBytes + offset32Bytes + 2*hashSize
+	if minSize < 0 || len(index.data) < minSize {
+		return fmt.Errorf("objectstore/packed: idx %q has truncated tables", index.idxName)
+	}
+
+	index.namesOffset = 8 + 256*4
+	index.offset32Offset = index.namesOffset + namesBytes + crcBytes
+	index.offset64Offset = index.offset32Offset + offset32Bytes
+
+	offset64Bytes := len(index.data) - index.offset64Offset - 2*hashSize
+	if offset64Bytes < 0 || offset64Bytes%8 != 0 {
+		return fmt.Errorf("objectstore/packed: idx %q has malformed 64-bit offset table", index.idxName)
+	}
+
+	index.offset64Count = offset64Bytes / 8
+
+	maxOffset64Count := max(index.numObjects-1, 0)
+	if index.offset64Count > maxOffset64Count {
+		return fmt.Errorf("objectstore/packed: idx %q has oversized 64-bit offset table", index.idxName)
+	}
+
+	return nil
+}