1 files changed, 123 insertions, 0 deletions
diff --git a/swarm/storage/feeds/id.go b/swarm/storage/feeds/id.go
new file mode 100644
index 000000000..dd813ae89
--- /dev/null
+++ b/swarm/storage/feeds/id.go
@@ -0,0 +1,123 @@
+// 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 feeds
+
+import (
+	"fmt"
+	"hash"
+	"strconv"
+
+	"github.com/ethereum/go-ethereum/common"
+	"github.com/ethereum/go-ethereum/swarm/storage/feeds/lookup"
+
+	"github.com/ethereum/go-ethereum/swarm/storage"
+)
+
+// ID uniquely identifies an update on the network.
+type ID struct {
+	Feed         `json:"feed"`
+	lookup.Epoch `json:"epoch"`
+}
+
+// ID layout:
+// Feed feedLength bytes
+// Epoch EpochLength
+const idLength = feedLength + lookup.EpochLength
+
+// Addr calculates the feed update chunk address corresponding to this ID
+func (u *ID) Addr() (updateAddr storage.Address) {
+	serializedData := make([]byte, idLength)
+	var cursor int
+	u.Feed.binaryPut(serializedData[cursor : cursor+feedLength])
+	cursor += feedLength
+
+	eid := u.Epoch.ID()
+	copy(serializedData[cursor:cursor+lookup.EpochLength], eid[:])
+
+	hasher := hashPool.Get().(hash.Hash)
+	defer hashPool.Put(hasher)
+	hasher.Reset()
+	hasher.Write(serializedData)
+	return hasher.Sum(nil)
+}
+
+// binaryPut serializes this instance into the provided slice
+func (u *ID) binaryPut(serializedData []byte) error {
+	if len(serializedData) != idLength {
+		return NewErrorf(ErrInvalidValue, "Incorrect slice size to serialize ID. Expected %d, got %d", idLength, len(serializedData))
+	}
+	var cursor int
+	if err := u.Feed.binaryPut(serializedData[cursor : cursor+feedLength]); err != nil {
+		return err
+	}
+	cursor += feedLength
+
+	epochBytes, err := u.Epoch.MarshalBinary()
+	if err != nil {
+		return err
+	}
+	copy(serializedData[cursor:cursor+lookup.EpochLength], epochBytes[:])
+	cursor += lookup.EpochLength
+
+	return nil
+}
+
+// binaryLength returns the expected size of this structure when serialized
+func (u *ID) binaryLength() int {
+	return idLength
+}
+
+// binaryGet restores the current instance from the information contained in the passed slice
+func (u *ID) binaryGet(serializedData []byte) error {
+	if len(serializedData) != idLength {
+		return NewErrorf(ErrInvalidValue, "Incorrect slice size to read ID. Expected %d, got %d", idLength, len(serializedData))
+	}
+
+	var cursor int
+	if err := u.Feed.binaryGet(serializedData[cursor : cursor+feedLength]); err != nil {
+		return err
+	}
+	cursor += feedLength
+
+	if err := u.Epoch.UnmarshalBinary(serializedData[cursor : cursor+lookup.EpochLength]); err != nil {
+		return err
+	}
+	cursor += lookup.EpochLength
+
+	return nil
+}
+
+// FromValues deserializes this instance from a string key-value store
+// useful to parse query strings
+func (u *ID) FromValues(values Values) error {
+	level, _ := strconv.ParseUint(values.Get("level"), 10, 32)
+	u.Epoch.Level = uint8(level)
+	u.Epoch.Time, _ = strconv.ParseUint(values.Get("time"), 10, 64)
+
+	if u.Feed.User == (common.Address{}) {
+		return u.Feed.FromValues(values)
+	}
+	return nil
+}
+
+// AppendValues serializes this structure into the provided string key-value store
+// useful to build query strings
+func (u *ID) AppendValues(values Values) {
+	values.Set("level", fmt.Sprintf("%d", u.Epoch.Level))
+	values.Set("time", fmt.Sprintf("%d", u.Epoch.Time))
+	u.Feed.AppendValues(values)
+}