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

Change-Id: I6c5e1a167216ad9b51e9da89460e9909465ae1bc
diff --git a/meframe/me_get.go b/meframe/me_get.go
new file mode 100644
index 0000000..f50e554
--- /dev/null
+++ b/meframe/me_get.go
@@ -0,0 +1,133 @@
+/*
+ * 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 GetRequestFrame(m *me.ManagedEntity, opt options) (gopacket.SerializableLayer, error) {
+	// Given mask sent in (could be default of 0xFFFF) get what is allowable.
+	// This will be all allowed if 0xFFFF is passed in, or a subset if a fixed
+	// number of items.
+	maxMask, err := checkAttributeMask(m, opt.attributeMask)
+	if err != nil {
+		return nil, err
+	}
+	// Now scan attributes and reduce mask to only those requested
+	var mask uint16
+	mask, err = calculateAttributeMask(m, maxMask)
+	if err != nil {
+		return nil, err
+	}
+	if mask == 0 {
+		// TODO: Is a Get request with no attributes valid?
+		return nil, errors.New("no attributes requested for GetRequest")
+	}
+	meLayer := &GetRequest{
+		MeBasePacket: MeBasePacket{
+			EntityClass:    m.GetClassID(),
+			EntityInstance: m.GetEntityID(),
+			Extended:       opt.frameFormat == ExtendedIdent,
+		},
+		AttributeMask: mask,
+	}
+	return meLayer, nil
+}
+
+func GetResponseFrame(m *me.ManagedEntity, opt options) (gopacket.SerializableLayer, error) {
+	mask, err := checkAttributeMask(m, opt.attributeMask)
+	if err != nil {
+		return nil, err
+	}
+	mask, err = calculateAttributeMask(m, mask)
+	if err != nil {
+		return nil, err
+	}
+	meLayer := &GetResponse{
+		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.AttributeFailure {
+		meLayer.UnsupportedAttributeMask = opt.unsupportedMask
+		meLayer.FailedAttributeMask = opt.attrExecutionMask
+	}
+	// Encode whatever we can
+	if meLayer.Result == me.Success || meLayer.Result == me.AttributeFailure {
+		// Encode results
+		// Get payload space available
+		maxPayload := maxPacketAvailable(m, opt)
+		payloadAvailable := int(maxPayload) - 2 - 4 // Less attribute mask and attribute error encoding
+		meDefinition := m.GetManagedEntityDefinition()
+		attrDefs := meDefinition.GetAttributeDefinitions()
+		attrMap := m.GetAttributeValueMap()
+
+		if mask != 0 {
+			// 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 {
+						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 if opt.failIfTruncated {
+						// TODO: Should we set truncate?
+						msg := fmt.Sprintf("out-of-space. Cannot fit attribute %v into GetResponse message",
+							attrDef.GetName())
+						return nil, me.NewMessageTruncatedError(msg)
+					} else {
+						// Add to existing 'failed' mask and update result
+						meLayer.FailedAttributeMask |= attrDef.Mask
+						meLayer.Result = me.AttributeFailure
+					}
+				}
+			}
+		}
+	}
+	return meLayer, nil
+}