/// <summary>
/// Loop over all branches, trying to locate one that is equal to the given opcode
/// If the branch is a branch itself, perform the locate recursively.
/// </summary>
/// <param name="opcode"></param>
/// <returns></returns>
internal override Opcode Locate(Opcode opcode)
{
Fx.Assert(!opcode.TestFlag(OpcodeFlags.Branch), "");
for (int i = 0, count = this.branches.Count; i < count; ++i)
{
Opcode branch = this.branches[i];
if (branch.TestFlag(OpcodeFlags.Branch))
{
// The branch is itself a branch. Since branch opcodes serve as branches in the exection
// path for a query, but don't comprise one of the opcodes used to actually perform it, we
// recursively try to locate an equivalent opcode inside the branch
Opcode subBranch = branch.Locate(opcode);
if (null != subBranch)
{
return(subBranch);
}
}
else if (branch.Equals(opcode))
{
return(branch);
}
}
return(null);
}
internal SubExprOpcode Add(Opcode opseq, SubExprEliminator elim)
{
Opcode start = this.FirstOp;
Opcode ops = opseq;
while (start != null && ops != null && start.Equals(ops))
{
start = start.Next;
ops = ops.Next;
}
if (ops == null)
{
if (start == null)
{
return(new SubExprOpcode(this));
}
else
{
SubExpr e = this.BranchAt(start, elim);
return(new SubExprOpcode(e));
}
}
else
{
if (start == null)
{
ops.DetachFromParent();
for (int i = 0; i < this.children.Count; ++i)
{
if (this.children[i].FirstOp.Equals(ops))
{
return(this.children[i].Add(ops, elim));
}
}
SubExpr e = new SubExpr(this, ops, elim.NewVarID());
this.AddChild(e);
return(new SubExprOpcode(e));
}
else
{
SubExpr e = this.BranchAt(start, elim);
ops.DetachFromParent();
SubExpr ee = new SubExpr(e, ops, elim.NewVarID());
e.AddChild(ee);
return(new SubExprOpcode(ee));
}
}
}
internal SubExprOpcode Add(Opcode opseq, SubExprEliminator elim)
{
Opcode firstOp = this.FirstOp;
Opcode op = opseq;
while (((firstOp != null) && (op != null)) && firstOp.Equals(op))
{
firstOp = firstOp.Next;
op = op.Next;
}
if (op == null)
{
if (firstOp == null)
{
return(new SubExprOpcode(this));
}
return(new SubExprOpcode(this.BranchAt(firstOp, elim)));
}
if (firstOp == null)
{
op.DetachFromParent();
for (int i = 0; i < this.children.Count; i++)
{
if (this.children[i].FirstOp.Equals(op))
{
return(this.children[i].Add(op, elim));
}
}
SubExpr expr2 = new SubExpr(this, op, elim.NewVarID());
this.AddChild(expr2);
return(new SubExprOpcode(expr2));
}
SubExpr parent = this.BranchAt(firstOp, elim);
op.DetachFromParent();
SubExpr expr = new SubExpr(parent, op, elim.NewVarID());
parent.AddChild(expr);
return(new SubExprOpcode(expr));
}
internal override Opcode Locate(Opcode opcode)
{
int num = 0;
int count = this.branches.Count;
while (num < count)
{
Opcode opcode2 = this.branches[num];
if (opcode2.TestFlag(OpcodeFlags.Branch))
{
Opcode opcode3 = opcode2.Locate(opcode);
if (opcode3 != null)
{
return(opcode3);
}
}
else if (opcode2.Equals(opcode))
{
return(opcode2);
}
num++;
}
return(null);
}
