VOL-4337: Code upgrade for 3/2020 G.988 support and remaining Extended Message Set support

Change-Id: I6c5e1a167216ad9b51e9da89460e9909465ae1bc
diff --git a/meframe/me_getnext.go b/meframe/me_getnext.go
new file mode 100644
index 0000000..090b333
--- /dev/null
+++ b/meframe/me_getnext.go
@@ -0,0 +1,132 @@
+/*
+ * Copyright (c) 2018 - present.  Boling Consulting Solutions (bcsw.net)
+ * Copyright 2020-present Open Networking Foundation
+
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+
+ * http://www.apache.org/licenses/LICENSE-2.0
+
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package meframe
+
+import (
+	"errors"
+	"fmt"
+	"github.com/google/gopacket"
+	. "github.com/opencord/omci-lib-go"
+	me "github.com/opencord/omci-lib-go/generated"
+)
+
+func GetNextRequestFrame(m *me.ManagedEntity, opt options) (gopacket.SerializableLayer, error) {
+	if opt.frameFormat == ExtendedIdent {
+		return nil, errors.New("extended message set for this message type is not supported")
+	}
+	// Validate attribute mask
+	mask, err := checkAttributeMask(m, opt.attributeMask)
+	if err != nil {
+		return nil, err
+	}
+	// Now scan attributes and reduce mask to only those requested
+	mask, err = calculateAttributeMask(m, mask)
+	if err != nil {
+		return nil, err
+	}
+	if mask == 0 {
+		return nil, errors.New("no attributes requested for GetNextRequest")
+	}
+	// TODO: If more than one attribute or the attribute requested is not a table attribute, return an error
+	// Common for all MEs
+	meLayer := &GetNextRequest{
+		MeBasePacket: MeBasePacket{
+			EntityClass:    m.GetClassID(),
+			EntityInstance: m.GetEntityID(),
+			Extended:       opt.frameFormat == ExtendedIdent,
+		},
+		AttributeMask:  mask,
+		SequenceNumber: opt.sequenceNumberCountOrSize,
+	}
+	return meLayer, nil
+}
+
+func GetNextResponseFrame(m *me.ManagedEntity, opt options) (gopacket.SerializableLayer, error) {
+	if opt.frameFormat == ExtendedIdent {
+		return nil, errors.New("extended message set for this message type is not supported")
+	}
+	// Validate attribute mask
+	mask, err := checkAttributeMask(m, opt.attributeMask)
+	if err != nil {
+		return nil, err
+	}
+	mask, err = calculateAttributeMask(m, mask)
+	if err != nil {
+		return nil, err
+	}
+	//
+	// Common for all MEs
+	meLayer := &GetNextResponse{
+		MeBasePacket: MeBasePacket{
+			EntityClass:    m.GetClassID(),
+			EntityInstance: m.GetEntityID(),
+			Extended:       opt.frameFormat == ExtendedIdent,
+		},
+		Result:        opt.result,
+		AttributeMask: 0,
+		Attributes:    make(me.AttributeValueMap),
+	}
+	if meLayer.Result == me.Success {
+		// Get payload space available
+		maxPayload := maxPacketAvailable(m, opt)
+		payloadAvailable := int(maxPayload) - 3 // Less results and attribute mask
+		meDefinition := m.GetManagedEntityDefinition()
+		attrDefs := meDefinition.GetAttributeDefinitions()
+		attrMap := m.GetAttributeValueMap()
+
+		if mask == 0 {
+			return nil, errors.New("no attributes requested for GetNextResponse")
+		}
+		// TODO: If more than one attribute or the attribute requested is not a table attribute, return an error
+		// Iterate down the attributes (Attribute 0 is the ManagedEntity ID)
+		var attrIndex uint
+		for attrIndex = 1; attrIndex <= 16; attrIndex++ {
+			// Is this attribute requested
+			if mask&(1<<(16-attrIndex)) != 0 {
+				// Get definitions since we need the name
+				attrDef, ok := attrDefs[attrIndex]
+				if !ok {
+					msg := fmt.Sprintf("Unexpected error, index %v not valued for ME %v",
+						attrIndex, meDefinition.GetName())
+					return nil, errors.New(msg)
+				}
+				var attrValue interface{}
+				attrValue, ok = attrMap[attrDef.Name]
+				if !ok || attrValue == nil {
+					msg := fmt.Sprintf("Unexpected error, attribute %v not provided in ME %v: %v",
+						attrDef.GetName(), meDefinition.GetName(), m)
+					return nil, errors.New(msg)
+				}
+				// Is space available?
+				if attrDef.Size <= payloadAvailable {
+					// Mark bit handled
+					mask &= ^attrDef.Mask
+					meLayer.AttributeMask |= attrDef.Mask
+					meLayer.Attributes[attrDef.Name] = attrValue
+					payloadAvailable -= attrDef.Size
+				} else {
+					// TODO: Should we set truncate?
+					msg := fmt.Sprintf("out-of-space. Cannot fit attribute %v into GetNextResponse message",
+						attrDef.GetName())
+					return nil, me.NewMessageTruncatedError(msg)
+				}
+			}
+		}
+	}
+	return meLayer, nil
+}