1 files changed, 95 insertions, 0 deletions
diff --git a/index.go b/index.go
new file mode 100644
index 0000000..1ba040e
--- /dev/null
+++ b/index.go
@@ -0,0 +1,95 @@
+package main
+
+import (
+	"crypto/rand"
+	"encoding/binary"
+	"sync"
+)
+
+/* Index=0 is reserved for unset indecies
+ *
+ */
+
+type IndexTableEntry struct {
+	peer      *Peer
+	handshake *Handshake
+	keyPair   *KeyPair
+}
+
+type IndexTable struct {
+	mutex sync.RWMutex
+	table map[uint32]IndexTableEntry
+}
+
+func randUint32() (uint32, error) {
+	var buff [4]byte
+	_, err := rand.Read(buff[:])
+	value := binary.LittleEndian.Uint32(buff[:])
+	return value, err
+}
+
+func (table *IndexTable) Init() {
+	table.mutex.Lock()
+	table.table = make(map[uint32]IndexTableEntry)
+	table.mutex.Unlock()
+}
+
+func (table *IndexTable) Delete(index uint32) {
+	if index == 0 {
+		return
+	}
+	table.mutex.Lock()
+	delete(table.table, index)
+	table.mutex.Unlock()
+}
+
+func (table *IndexTable) Insert(key uint32, value IndexTableEntry) {
+	table.mutex.Lock()
+	table.table[key] = value
+	table.mutex.Unlock()
+}
+
+func (table *IndexTable) NewIndex(peer *Peer) (uint32, error) {
+	for {
+		// generate random index
+
+		index, err := randUint32()
+		if err != nil {
+			return index, err
+		}
+		if index == 0 {
+			continue
+		}
+
+		// check if index used
+
+		table.mutex.RLock()
+		_, ok := table.table[index]
+		table.mutex.RUnlock()
+		if ok {
+			continue
+		}
+
+		// map index to handshake
+
+		table.mutex.Lock()
+		_, found := table.table[index]
+		if found {
+			table.mutex.Unlock()
+			continue
+		}
+		table.table[index] = IndexTableEntry{
+			peer:      peer,
+			handshake: &peer.handshake,
+			keyPair:   nil,
+		}
+		table.mutex.Unlock()
+		return index, nil
+	}
+}
+
+func (table *IndexTable) Lookup(id uint32) IndexTableEntry {
+	table.mutex.RLock()
+	defer table.mutex.RUnlock()
+	return table.table[id]
+}