SCCP: Be able to parse a DT1 message

SCCP.st

@@ -400,6 +400,21 @@ SCCPMessage subclass: SCCPConnectionData [
                 yourself.
     ]
 
+    SCCPConnectionData class >> parseFrom: aByteArray [
+        | more_data var_start addr size data |
+        addr := SCCPAddrReference fromByteArray: (aByteArray copyFrom: 2).
+        more_data := aByteArray at: 5.
+        more_data = 0 ifFalse: [
+            Error signal: 'Fragmented data is not supported.'.
+        ].
+
+        var_start := aByteArray at: 6.
+        size := aByteArray at: 6 + var_start.
+        data := aByteArray copyFrom: (6 + var_start + 1)  to: (6 + var_start + size).
+
+        ^ SCCPConnectionData initWith: addr data: data.
+    ]
+
     dst: aDst [
         <category: 'private'>
         dst := aDst.
@@ -414,6 +429,14 @@ SCCPMessage subclass: SCCPConnectionData [
         ].
     ]
 
+    dst [
+        ^ dst
+    ]
+
+    data [
+        ^ data
+    ]
+
     writeOn: aMsg [
         | dat |
         <category: 'conversion'>

Tests.st

@@ -23,11 +23,17 @@ TestCase subclass: SCCPTests [
     ]
 
     testDT1 [
-        | dt1 msg |
+        | dt1 msg target |
+        target := #(6 1 4 0 0 1 4 49 50 51 52) asByteArray.
         dt1 := SCCPConnectionData initWith: 16r401 data: '1234' asByteArray.
         msg := dt1 toMessage asByteArray.
 
-        self assert: msg = #(6 1 4 0 0 1 4 49 50 51 52) asByteArray.
+        self assert: msg = target.
+
+        dt1 := SCCPMessage decode: target.
+        self assert: dt1 dst = 16r401.
+        self assert: dt1 data = '1234' asByteArray.
+        self assert: dt1 toMessage asByteArray = target.
     ]
 
     testCR [