1 files changed, 117 insertions, 0 deletions
diff --git a/swarm/storage/mru/lookup.go b/swarm/storage/mru/lookup.go
new file mode 100644
index 000000000..eb28336e1
--- /dev/null
+++ b/swarm/storage/mru/lookup.go
@@ -0,0 +1,117 @@
+// Copyright 2018 The go-ethereum Authors
+// This file is part of the go-ethereum library.
+//
+// The go-ethereum library is free software: you can redistribute it and/or modify
+// it under the terms of the GNU Lesser General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// The go-ethereum library is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+// GNU Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
+
+package mru
+
+import (
+	"encoding/binary"
+	"hash"
+
+	"github.com/ethereum/go-ethereum/swarm/storage"
+)
+
+// LookupParams is used to specify constraints when performing an update lookup
+// Limit defines whether or not the lookup should be limited
+// If Limit is set to true then Max defines the amount of hops that can be performed
+type LookupParams struct {
+	UpdateLookup
+	Limit uint32
+}
+
+// RootAddr returns the metadata chunk address
+func (r *LookupParams) RootAddr() storage.Address {
+	return r.rootAddr
+}
+
+func NewLookupParams(rootAddr storage.Address, period, version uint32, limit uint32) *LookupParams {
+	return &LookupParams{
+		UpdateLookup: UpdateLookup{
+			period:   period,
+			version:  version,
+			rootAddr: rootAddr,
+		},
+		Limit: limit,
+	}
+}
+
+// LookupLatest generates lookup parameters that look for the latest version of a resource
+func LookupLatest(rootAddr storage.Address) *LookupParams {
+	return NewLookupParams(rootAddr, 0, 0, 0)
+}
+
+// LookupLatestVersionInPeriod generates lookup parameters that look for the latest version of a resource in a given period
+func LookupLatestVersionInPeriod(rootAddr storage.Address, period uint32) *LookupParams {
+	return NewLookupParams(rootAddr, period, 0, 0)
+}
+
+// LookupVersion generates lookup parameters that look for a specific version of a resource
+func LookupVersion(rootAddr storage.Address, period, version uint32) *LookupParams {
+	return NewLookupParams(rootAddr, period, version, 0)
+}
+
+// UpdateLookup represents the components of a resource update search key
+type UpdateLookup struct {
+	period   uint32
+	version  uint32
+	rootAddr storage.Address
+}
+
+// 4 bytes period
+// 4 bytes version
+// storage.Keylength for rootAddr
+const updateLookupLength = 4 + 4 + storage.KeyLength
+
+// UpdateAddr calculates the resource update chunk address corresponding to this lookup key
+func (u *UpdateLookup) UpdateAddr() (updateAddr storage.Address) {
+	serializedData := make([]byte, updateLookupLength)
+	u.binaryPut(serializedData)
+	hasher := hashPool.Get().(hash.Hash)
+	defer hashPool.Put(hasher)
+	hasher.Reset()
+	hasher.Write(serializedData)
+	return hasher.Sum(nil)
+}
+
+// binaryPut serializes this UpdateLookup instance into the provided slice
+func (u *UpdateLookup) binaryPut(serializedData []byte) error {
+	if len(serializedData) != updateLookupLength {
+		return NewErrorf(ErrInvalidValue, "Incorrect slice size to serialize UpdateLookup. Expected %d, got %d", updateLookupLength, len(serializedData))
+	}
+	if len(u.rootAddr) != storage.KeyLength {
+		return NewError(ErrInvalidValue, "UpdateLookup.binaryPut called without rootAddr set")
+	}
+	binary.LittleEndian.PutUint32(serializedData[:4], u.period)
+	binary.LittleEndian.PutUint32(serializedData[4:8], u.version)
+	copy(serializedData[8:], u.rootAddr[:])
+	return nil
+}
+
+// binaryLength returns the expected size of this structure when serialized
+func (u *UpdateLookup) binaryLength() int {
+	return updateLookupLength
+}
+
+// binaryGet restores the current instance from the information contained in the passed slice
+func (u *UpdateLookup) binaryGet(serializedData []byte) error {
+	if len(serializedData) != updateLookupLength {
+		return NewErrorf(ErrInvalidValue, "Incorrect slice size to read UpdateLookup. Expected %d, got %d", updateLookupLength, len(serializedData))
+	}
+	u.period = binary.LittleEndian.Uint32(serializedData[:4])
+	u.version = binary.LittleEndian.Uint32(serializedData[4:8])
+	u.rootAddr = storage.Address(make([]byte, storage.KeyLength))
+	copy(u.rootAddr[:], serializedData[8:])
+	return nil
+}