public override void Emit(SourceBuilder sourceCode)
{
// --- move list head from current position to random position ---
if (Type == RandomizeListHeadsTypes.GraphElements)
{
// emit declaration of variable containing random position to move list head to
string variableContainingRandomPosition =
"random_position_" + PatternElementName;
sourceCode.AppendFormat("int {0}", variableContainingRandomPosition);
// emit initialization with ramdom position
string graphMemberContainingElementListCountsByType =
IsNode ? "nodesByTypeCounts" : "edgesByTypeCounts";
string variableContainingTypeIDForCandidate =
NamesOfEntities.TypeIdForCandidateVariable(PatternElementName);
sourceCode.AppendFormat(" = random.Next(graph.{0}[{1}]);\n",
graphMemberContainingElementListCountsByType,
variableContainingTypeIDForCandidate);
// emit declaration of variable containing element at random position
string typeOfVariableContainingElementAtRandomPosition = "GRGEN_LGSP."
+ (IsNode ? "LGSPNode" : "LGSPEdge");
string variableContainingElementAtRandomPosition =
"random_element_" + PatternElementName;
sourceCode.AppendFrontFormat("{0} {1}",
typeOfVariableContainingElementAtRandomPosition,
variableContainingElementAtRandomPosition);
// emit initialization with element list head
string graphMemberContainingElementListHeadByType =
IsNode ? "nodesByTypeHeads" : "edgesByTypeHeads";
sourceCode.AppendFormat(" = graph.{0}[{1}];\n",
graphMemberContainingElementListHeadByType, variableContainingTypeIDForCandidate);
// emit iteration to get element at random position
sourceCode.AppendFrontFormat(
"for(int i = 0; i < {0}; ++i) {1} = {1}.Next;\n",
variableContainingRandomPosition, variableContainingElementAtRandomPosition);
// iteration left, element is the one at the requested random position
// move list head after element at random position,
sourceCode.AppendFrontFormat("graph.MoveHeadAfter({0});\n",
variableContainingElementAtRandomPosition);
// effect is new random starting point for following iteration
}
else //Type == RandomizeListHeadsTypes.IncidentEdges
{
// emit "randomization only if list is not empty"
string variableContainingStartingPointNode =
NamesOfEntities.CandidateVariable(StartingPointNodeName);
string memberOfNodeContainingListHead =
IsIncoming ? "lgspInhead" : "lgspOuthead";
sourceCode.AppendFrontFormat("if({0}.{1}!=null)\n",
variableContainingStartingPointNode, memberOfNodeContainingListHead);
sourceCode.AppendFront("{\n");
sourceCode.Indent();
// emit declaration of variable containing random position to move list head to, initialize it to 0
string variableContainingRandomPosition =
"random_position_" + PatternElementName;
sourceCode.AppendFrontFormat("int {0} = 0;", variableContainingRandomPosition);
// misuse variable to store length of list which is computed within the follwing iteration
string memberOfEdgeContainingNextEdge =
IsIncoming ? "lgspInNext" : "lgspOutNext";
sourceCode.AppendFrontFormat("for(GRGEN_LGSP.LGSPEdge edge = {0}.{1}; edge!={0}.{1}; edge=edge.{2}) ++{3};\n",
variableContainingStartingPointNode, memberOfNodeContainingListHead,
memberOfEdgeContainingNextEdge, variableContainingRandomPosition);
// emit initialization of variable containing ramdom position
// now that the necessary length of the list is known after the iteration
// given in the variable itself
sourceCode.AppendFrontFormat("{0} = random.Next({0});\n",
variableContainingRandomPosition);
// emit declaration of variable containing edge at random position
string variableContainingEdgeAtRandomPosition =
"random_element_" + PatternElementName;
sourceCode.AppendFrontFormat("GRGEN_LGSP.LGSPEdge {0}",
variableContainingEdgeAtRandomPosition);
// emit initialization with edge list head
sourceCode.AppendFormat(" = {0}.{1};\n",
variableContainingStartingPointNode, memberOfNodeContainingListHead);
// emit iteration to get edge at random position
sourceCode.AppendFrontFormat(
"for(int i = 0; i < {0}; ++i) {1} = {1}.{2};\n",
variableContainingRandomPosition,
variableContainingEdgeAtRandomPosition,
memberOfEdgeContainingNextEdge);
// iteration left, edge is the one at the requested random position
// move list head after edge at random position,
if (IsIncoming)
{
sourceCode.AppendFrontFormat("{0}.MoveInHeadAfter({1});\n",
variableContainingStartingPointNode,
variableContainingEdgeAtRandomPosition);
}
else
{
sourceCode.AppendFrontFormat("{0}.MoveOutHeadAfter({1});\n",
variableContainingStartingPointNode,
variableContainingEdgeAtRandomPosition);
}
// close list is not empty check
sourceCode.Unindent();
sourceCode.AppendFront("}\n");
// effect is new random starting point for following iteration
}
}